JP2023076662A - Substrate processing method - Google Patents

Abstract

To provide a substrate processing method capable of reducing pattern collapse occurring when a substrate is dried by sublimation drying.SOLUTION: A dry pretreatment liquid which is a solution containing a sublimable substance that changes to a gas without passing through a liquid and a solvent that dissolves with the sublimable substance is supplied to the surface of a substrate on which a pattern is formed. After that, by evaporating the solution from the dry pretreatment liquid on the surface of the substrate, a solid containing a sublimable substance is formed on the surface of the substrate. After that, the solid is removed from the surface of the substrate by sublimation. The ratio of the solid thickness to the pattern height multiplied by 100 is greater than 76 and less than 219.SELECTED DRAWING: Figure 11

Description

The present disclosure relates to a substrate processing method and substrate processing apparatus for processing a substrate, and a pre-drying treatment liquid supplied to the surface of the substrate before drying the surface of the substrate. Substrates to be processed include, for example, semiconductor wafers, liquid crystal display device substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, ceramic substrates, solar cell substrates, organic EL (electroluminescence) substrates. ) FPD (Flat Panel Display) substrates such as display devices are included.

2. Description of the Related Art In the manufacturing process of semiconductor devices, liquid crystal display devices, and the like, substrates such as semiconductor wafers and glass substrates for liquid crystal display devices are processed as necessary. Such processing includes supplying a processing liquid such as a chemical liquid or a rinse liquid to the substrate. After the processing liquid is supplied, the processing liquid is removed from the substrate and the substrate is dried. 2. Description of the Related Art In a single-wafer type substrate processing apparatus that processes substrates one by one, spin drying is performed to dry the substrates by removing liquid adhering to the substrates by rotating the substrates at high speed.

When a pattern is formed on the surface of the substrate, the pattern may collapse when the substrate is dried due to the force caused by the surface tension of the processing liquid adhering to the substrate. As countermeasures, a method of supplying a liquid having a low surface tension such as IPA (isopropyl alcohol) to the substrate, or supplying a hydrophobizing agent to the substrate to bring the contact angle of the liquid to the pattern close to 90 degrees is adopted. However, even if IPA or a hydrophobizing agent is used, the collapsing force for collapsing the pattern cannot be reduced to zero. There is

In recent years, sublimation drying has attracted attention as a technique for preventing pattern collapse. For example, Patent Literature 1 discloses a substrate processing method and a substrate processing apparatus that perform sublimation drying. In the sublimation drying described in Patent Document 1, a sublimation substance solution is supplied to the upper surface of the substrate, and DIW on the substrate is replaced with the sublimation substance solution. After that, the solvent for the sublimable substance is dried to deposit the sublimable substance. Thereby, a film made of a solid sublimable substance is formed on the upper surface of the substrate. In paragraph 0028 of Patent Document 1, it is preferable that the film thickness 't' of the film made of a sublimable substance be as thin as possible as long as it sufficiently covers the convex portion 101 of the pattern. ” is stated. After the film of solid sublimable substance is formed, the substrate is heated. Thereby, the sublimable substance on the substrate is sublimated and removed from the substrate.

JP 2012-243869 A

In general, sublimation drying has a lower pattern collapse rate than conventional drying methods such as spin drying that removes liquid by rotating the substrate at high speed and IPA drying that uses IPA. However, if the strength of the pattern is extremely low, even if sublimation drying is carried out, it may not be possible to sufficiently prevent the pattern from collapsing. According to the studies of the present inventors, one of the causes is the thickness of the solidified body containing the sublimable substance. In Patent Document 1, "The film thickness 't' of the film made of a sublimable substance is preferably as thin as possible as long as it sufficiently covers the convex portions 101 of the pattern. , and the thickness of the film made of the sublimable substance is not sufficiently considered.

Accordingly, one object of the present disclosure is to provide a substrate processing method, a substrate processing apparatus, and a pre-drying treatment liquid that can reduce pattern collapse that occurs when a substrate is dried by sublimation drying. .

In one embodiment of the present disclosure for achieving the above object, a pattern is formed using a drying pretreatment liquid that is a solution containing a sublimable substance that changes to gas without passing through a liquid and a solvent that dissolves with the sublimable substance. a pre-drying treatment liquid supply step of supplying the pre-drying treatment liquid onto the surface of the substrate; and evaporating the solvent from the pre-drying treatment liquid on the surface of the substrate to form a solidified body containing the sublimable substance on the surface of the substrate. and a sublimation step of removing the solidified body from the surface of the substrate by sublimating the solidified body. greater than and less than 219.

According to this method, a dry pretreatment liquid containing a sublimable substance corresponding to a solute and a solvent is supplied to the surface of the patterned substrate. After that, the solvent is evaporated from the drying pretreatment liquid. Thereby, a solidified body containing a sublimable substance is formed on the surface of the substrate. After that, the solidified body on the substrate is changed into gas without passing through liquid. This removes the solidified material from the surface of the substrate. Therefore, compared with conventional drying methods such as spin drying, the pattern collapse rate can be reduced.

When the solvent is evaporated from the dry pretreatment liquid, a solidified body containing a sublimable substance is formed on the surface of the substrate. Assuming that the ratio of the thickness of the solid to the height of the pattern is multiplied by 100 to define the embedding rate, the embedding rate at the point when the solid is formed is more than 76 and less than 219. When the embedding rate is out of this range, the number of pattern collapses increases depending on the strength of the pattern. Conversely, if the embedding rate is within this range, the number of pattern collapses can be reduced even if the pattern strength is low. Therefore, even if the strength of the pattern is low, the collapse rate of the pattern can be reduced.

In the above embodiments, at least one of the following features may be added to the substrate processing method.
The sublimable substance includes at least one of camphor and naphthalene.
The solvent includes at least one of IPA (isopropyl alcohol), acetone, and PGEE (propylene glycol monoethyl ether).

The solvent is IPA, and the mass percent concentration of the sublimable substance in the drying pretreatment liquid is more than 0.62 and less than 2.06.
The solvent is acetone, and the mass percent concentration of the sublimable substance in the pre-drying treatment liquid is more than 0.62 and less than or equal to 0.96.

The solvent is PGEE, and the mass percent concentration of the sublimable substance in the drying pretreatment liquid is more than 3.55 and less than or equal to 6.86.
The pre-drying treatment liquid supplied to the surface of the substrate in the pre-drying treatment liquid supply step contains the sublimable substance containing a hydrophobic group, the solvent, a hydrophobic group and a hydrophilic group, and the sublimable substance and an adsorbent that is more hydrophilic than the solution.

According to this method, a dry pretreatment liquid containing an adsorptive substance in addition to a sublimable substance and a solvent is supplied to the surface of the patterned substrate. After that, the solvent is evaporated from the drying pretreatment liquid. Thereby, a solidified body containing a sublimable substance is formed on the surface of the substrate. After that, the solidified body on the substrate is changed into gas without passing through liquid. This removes the solidified material from the surface of the substrate. Therefore, compared with conventional drying methods such as spin drying, the pattern collapse rate can be reduced.

A sublimable substance is a substance containing a hydrophobic group in its molecule. An adsorbent is a substance containing a hydrophobic group and a hydrophilic group in its molecule. The hydrophilicity of the adsorptive material is higher than that of the sublimable material. Regardless of whether the surface of the pattern is hydrophilic or hydrophobic, or whether the surface of the pattern includes a hydrophilic portion and a hydrophobic portion, the adsorbent in the pre-drying treatment liquid adsorbs to the surface of

Specifically, when the pattern surface is hydrophilic, the hydrophilic group of the adsorbent in the pre-drying treatment liquid adheres to the pattern surface, and the hydrophobic group of the sublimable substance in the pre-drying treatment liquid adheres to the adsorbent. It attaches to hydrophobic groups. Thereby, the sublimable substance is held on the surface of the pattern via the adsorbing substance. When the surface of the pattern is hydrophobic, at least the hydrophobic group of the sublimable substance adheres to the surface of the pattern. Therefore, regardless of whether the surface of the pattern is hydrophilic or hydrophobic, or whether the surface of the pattern contains both hydrophilic and hydrophobic portions, the sublimable substance is deposited before evaporation of the solvent. It is held on or near the surface of the pattern.

When the sublimable substance is hydrophilic and the surface of the pattern is hydrophilic, the sublimable substance is attracted to the surface of the pattern by electrical attraction. On the other hand, when the sublimating substance is hydrophobic and the surface of the pattern is hydrophilic, such attractive force is weak or does not occur, so the sublimating substance is less likely to adhere to the surface of the pattern. Furthermore, in addition to the fact that the sublimable substance is hydrophobic and the surface of the pattern is hydrophilic, if the space between the patterns is extremely narrow, it is conceivable that a sufficient amount of the sublimable substance will not enter between the patterns. . These phenomena also occur when the sublimation substance is hydrophilic and the surface of the pattern is hydrophobic.

If the solvent is evaporated without the sublimable substance on or near the surface of the pattern, the solvent in contact with the surface of the pattern may exert a collapsing force on the pattern, causing the pattern to collapse. If the solvent is evaporated without a sufficient amount of the sublimable substance between the patterns, the gaps between the patterns may not be filled with the solidified material, and the patterns may collapse. Placing a sublimable substance on or near the surface of the pattern before evaporating the solvent can reduce such collapse. Thereby, the collapse rate of the pattern can be reduced.

The hydrophilic group may be a hydroxyl group (hydroxy group, hydroxyl group), a carboxy group (COOH), an amino group (NH ₂ ), or a carbonyl group (CO), or may be other groups. The hydrophobic group may be a hydrocarbon group, an alkyl group (C _n H _2n+1 ), a cycloalkyl group (C _n H _2n+1 ), a phenyl group (C ₆ H ₅ ), or other groups. good too.

The adsorptive substance is a sublimable substance.
According to this method, not only the sublimable substance but also the adsorptive substance have sublimability. Adsorbents change from solid to gas at normal temperature or pressure without passing through liquid. When at least part of the surface of the pattern is hydrophilic, the solvent evaporates while the adsorbent in the pre-drying treatment liquid is adsorbed on the surface of the pattern. The adsorbed material changes from liquid to solid on the surface of the pattern. This forms a solidified body containing the adsorbent and the sublimable material. After that, the solid of the adsorbent changes to gas without going through liquid on the surface of the pattern. Therefore, the collapsing force can be reduced compared to the case where the liquid is vaporized on the surface of the pattern.

The concentration of the adsorbent in the pre-drying treatment liquid is lower than the concentration of the solvent in the pre-drying treatment liquid.
According to this method, a pre-drying treatment liquid having a low adsorbent concentration is supplied to the surface of the substrate. When at least part of the surface of the pattern is hydrophilic, hydrophilic groups of the adsorbent adhere to the surface of the pattern, forming a monomolecular film of the adsorbent along the surface of the pattern. When the concentration of the adsorbent is high, multiple monomolecular films are stacked to form a laminated film of the adsorbent along the surface of the pattern. In this case, the sublimable substance is retained on the surface of the pattern through the layered film of the adsorbent. If the layered film of the adsorbing substance is thick, the sublimable substance entering between the patterns is reduced. Therefore, by lowering the concentration of the adsorbed substance, more sublimable substance can enter between the patterns.

When at least part of the surface of the pattern is hydrophilic, the concentration of the adsorbent in the pre-drying treatment liquid may be a value at which a monomolecular film of the adsorbate is formed on the surface of the pattern. and may exceed this value. In the former case, the sublimable substance is retained on the surface of the pattern via the monomolecular film of the adsorbent. Therefore, even if at least part of the surface of the pattern is hydrophilic, the sublimable substance can be arranged near the surface of the pattern. Furthermore, since only the thinnest monomolecular film of the adsorbent is interposed between the sublimable substance and the pattern, a sufficient amount of the sublimable substance can enter between the patterns.

The sublimable substance is more hydrophobic than the adsorptive substance. The solubility of the sublimable material in oil is higher than the solubility of the adsorbent material in oil. In other words, the solubility of the sublimable material in water is lower than the solubility of the adsorbent material in water.
According to this method, a pre-drying treatment liquid containing a sublimable substance having higher hydrophobicity than an adsorbent is supplied to the surface of the substrate. Since both the sublimable substance and the adsorptive substance contain hydrophobic groups, both the sublimable substance and the adsorptive substance can adhere to the surface of the pattern when at least part of the surface of the pattern is hydrophobic. However, since the affinity between the sublimable substance and the pattern is higher than the affinity between the adsorbent and the pattern, more sublimable substance adheres to the surface of the pattern than the adsorbate. This allows more sublimable substance to adhere to the surface of the pattern.

Another embodiment of the present disclosure supplies a dry pretreatment liquid, which is a solution containing a sublimable substance that changes to gas without passing through a liquid and a solvent that dissolves with the sublimable substance, to the surface of the substrate on which the pattern is formed. and a solidified body forming means for forming a solidified body containing the sublimable substance on the surface of the substrate by evaporating the solvent from the predrying treatment liquid on the surface of the substrate. and sublimation means for removing the solidified body from the surface of the substrate by sublimating the solidified body, wherein a ratio of the thickness of the solidified body to the height of the pattern multiplied by 100 is more than 76 and less than 219. provides a substrate processing apparatus. According to this configuration, the same effects as those of the substrate processing method described above can be obtained.

Yet another embodiment of the present disclosure is a pre-drying treatment liquid supplied to the surface of a patterned substrate before drying the surface of the substrate, the liquid sublimating into a gas without passing through a liquid. A solidified body containing a substance and a solvent that dissolves with the sublimable substance is formed on the surface of the substrate by evaporating the solvent from the pretreatment liquid for drying on the surface of the substrate. As a result, the concentration of the sublimable substance is adjusted so that the ratio of the thickness of the solidified body to the height of the pattern multiplied by 100 is greater than 76 and less than 219 to provide a pre-drying treatment liquid. . According to this configuration, the same effects as those of the substrate processing method described above can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic diagram which looked at the substrate processing apparatus which concerns on 1st Embodiment of this invention from the top. It is the schematic diagram which looked at the substrate processing apparatus from the side. FIG. 2 is a schematic diagram of the interior of a processing unit provided in the substrate processing apparatus as seen horizontally. FIG. 3 is a schematic diagram showing a pre-drying treatment liquid supply unit provided in the substrate processing apparatus; It is a block diagram which shows the hardware of a control device. FIG. 4 is a process chart for explaining an example of substrate processing according to the first embodiment; FIG. 6 is a schematic diagram showing the state of the substrate when the substrate shown in FIG. 5 is being processed; FIG. 6 is a schematic diagram showing the state of the substrate when the substrate shown in FIG. 5 is being processed; FIG. 6 is a schematic diagram showing the state of the substrate when the substrate shown in FIG. 5 is being processed; 4 is a graph showing an image of how the thickness of the liquid film of the pre-drying treatment liquid on the substrate decreases due to the evaporation of the solvent. 4 is a graph showing an example of the relationship between the initial concentration of a sublimable substance and the thickness of a solidified body; FIG. 10 is a table showing an example of the embedding rate and the pattern collapse rate obtained when a plurality of samples in which patterns of similar shape and intensity were formed were processed while varying the initial concentration of camphor. FIG. FIG. 10 is a line graph showing the relationship between the concentration of camphor and the pattern collapse rate in FIG. 9; FIG. FIG. 10 is a line graph showing the relationship between the embedding rate and the pattern collapse rate in FIG. 9; FIG. FIG. 10 is a schematic diagram for explaining the mechanism assumed for the phenomenon that the pattern collapse rate increases when the solidified body is too thick. FIG. 10 is a schematic diagram for explaining the mechanism assumed for the phenomenon that the pattern collapse rate increases when the solidified body is too thin. FIG. 10 is a table showing an example of pattern collapse rates obtained when a plurality of samples in which patterns having similar shapes and intensities were formed were treated while varying the initial concentration of camphor. FIG. FIG. 10 is a table showing an example of pattern collapse rates obtained when a plurality of samples in which patterns having similar shapes and intensities were formed were treated while varying the initial concentration of camphor. FIG. FIG. 10 is a table showing an example of pattern collapse rates obtained when a plurality of samples in which patterns having similar shapes and intensities were formed were treated while varying the initial concentration of camphor. FIG. FIG. 15 is a line graph showing the relationship between the concentration of camphor and the pattern collapse rate in FIG. 14; FIG. 16 is a line graph showing the relationship between the concentration of camphor and the pattern collapse rate in FIG. 15; FIG. 17 is a line graph showing the relationship between the concentration of camphor and the pattern collapse rate in FIG. 16; FIG. 20 is a graph in which the polygonal lines of FIGS. 17 to 19 are superimposed; FIG. FIG. 7 is a schematic diagram of the inside of a processing unit provided in the substrate processing apparatus according to the second embodiment, viewed horizontally. It is process drawing for demonstrating an example of a process of the board|substrate which concerns on 2nd Embodiment. FIG. 10 is a cross-sectional view of a substrate for explaining a phenomenon assumed to occur on the pattern surface to which the pre-drying treatment liquid is supplied; FIG. 3 is a cross-sectional view of a substrate for explaining the same phenomenon; FIG. 3 is a cross-sectional view of a substrate for explaining the same phenomenon; FIG. 3 is a cross-sectional view of a substrate for explaining the same phenomenon; FIG. 3 is a cross-sectional view of a substrate for explaining the same phenomenon; FIG. 3 is a cross-sectional view of a substrate for explaining the same phenomenon;

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
In the following description, unless otherwise specified, the atmospheric pressure in the substrate processing apparatus 1 is assumed to be maintained at the atmospheric pressure in the clean room in which the substrate processing apparatus 1 is installed (for example, 1 atmospheric pressure or a value in the vicinity thereof). .
FIG. 1A is a schematic top view of a substrate processing apparatus 1 according to a first embodiment of the present invention. FIG. 1B is a schematic diagram of the substrate processing apparatus 1 viewed from the side.

As shown in FIG. 1A, the substrate processing apparatus 1 is a single-wafer type apparatus that processes disc-shaped substrates W such as semiconductor wafers one by one. The substrate processing apparatus 1 includes a load port LP that holds a carrier C that accommodates substrates W, and a plurality of processes for processing the substrates W transported from the carrier C on the load port LP with a processing fluid such as a processing liquid or a processing gas. It includes a unit 2 , a transport robot that transports substrates W between the carrier C on the load port LP and the processing unit 2 , and a controller 3 that controls the substrate processing apparatus 1 .

The transport robots include an indexer robot IR that loads and unloads substrates W into and out of carriers C on load port LP, and a center robot CR that loads and unloads substrates W into and out of a plurality of processing units 2 . The indexer robot IR transports substrates W between the load port LP and the center robot CR, and the center robot CR transports the substrates W between the indexer robot IR and the processing units 2 . The center robot CR includes a hand H1 that supports the substrate W, and the indexer robot IR includes a hand H2 that supports the substrate W. As shown in FIG.

The plurality of processing units 2 form a plurality of towers TW arranged around the center robot CR in plan view. FIG. 1A shows an example in which four towers TW are formed. The center robot CR can access any tower TW. As shown in FIG. 1B, each tower TW includes a plurality (for example, three) of processing units 2 stacked one above the other.

FIG. 2 is a schematic horizontal view of the inside of the processing unit 2 provided in the substrate processing apparatus 1. As shown in FIG.
The processing unit 2 is a wet processing unit 2w that supplies the substrate W with processing liquid. The processing unit 2 includes a box-shaped chamber 4 having an internal space, and a spin chuck 10 that horizontally holds one substrate W in the chamber 4 and rotates it around a vertical rotation axis A1 that passes through the center of the substrate W. and a cylindrical processing cup 21 surrounding the spin chuck 10 around the rotation axis A1.

The chamber 4 includes a box-shaped partition wall 5 provided with a loading/unloading port 5b through which the substrate W passes, and a shutter 7 for opening and closing the loading/unloading port 5b. The FFU 6 (fan filter unit) is arranged above the blower port 5 a provided on the upper part of the partition wall 5 . The FFU 6 constantly supplies clean air (filtered air) into the chamber 4 from the blower port 5a. Gas in the chamber 4 is exhausted from the chamber 4 through an exhaust duct 8 connected to the bottom of the processing cup 21 . Thereby, a clean air downflow is always formed in the chamber 4 . The flow rate of the exhaust discharged to the exhaust duct 8 is changed according to the opening of the exhaust valve 9 arranged inside the exhaust duct 8 .

The spin chuck 10 includes a disc-shaped spin base 12 held in a horizontal posture, a plurality of chuck pins 11 holding the substrate W in a horizontal posture above the spin base 12 , and It includes a spin shaft 13 extending downward, and a spin motor 14 that rotates the spin base 12 and the plurality of chuck pins 11 by rotating the spin shaft 13 . The spin chuck 10 is not limited to a clamping type chuck in which a plurality of chuck pins 11 are brought into contact with the outer peripheral surface of the substrate W, and the back surface (lower surface) of the substrate W, which is a non-device forming surface, is attracted to the upper surface 12u of the spin base 12. Therefore, it may be a vacuum type chuck that holds the substrate W horizontally.

The processing cup 21 includes a plurality of guards 24 for receiving the processing liquid discharged outward from the substrate W, a plurality of cups 23 for receiving the processing liquid guided downward by the plurality of guards 24, a plurality of guards 24 and a plurality of cups 23 for receiving the processing liquid. and a cylindrical outer wall member 22 surrounding a cup 23 of the. FIG. 2 shows an example in which four guards 24 and three cups 23 are provided, and the outermost cup 23 is integrated with the third guard 24 from the top.

The guard 24 includes a cylindrical portion 25 surrounding the spin chuck 10 and an annular ceiling portion 26 extending obliquely upward from the upper end of the cylindrical portion 25 toward the rotation axis A1. The plurality of ceiling portions 26 overlap vertically, and the plurality of cylindrical portions 25 are arranged concentrically. An annular upper end of the ceiling portion 26 corresponds to an upper end 24u of the guard 24 surrounding the substrate W and the spin base 12 in plan view. The plurality of cups 23 are arranged below the plurality of cylindrical portions 25, respectively. The cup 23 forms an annular liquid receiving groove that receives the processing liquid guided downward by the guard 24 .

The processing unit 2 includes a guard lifting unit 27 that lifts and lowers the plurality of guards 24 individually. The guard lifting unit 27 positions the guard 24 at any position from the upper position to the lower position. FIG. 2 shows two guards 24 in the upper position and the remaining two guards 24 in the lower position. The upper position is a position where the upper end 24u of the guard 24 is arranged above the holding position where the substrate W held by the spin chuck 10 is arranged. The lower position is a position where the upper end 24u of the guard 24 is arranged below the holding position.

At least one guard 24 is placed in the upper position when supplying the processing liquid to the rotating substrate W. As shown in FIG. When the processing liquid is supplied to the substrate W in this state, the processing liquid supplied to the substrate W is shaken off around the substrate W. As shown in FIG. The shaken-off processing liquid collides with the inner surface of the guard 24 horizontally facing the substrate W and is guided to the cup 23 corresponding to the guard 24 . Thereby, the processing liquid discharged from the substrate W is collected in the processing cup 21 .

The processing unit 2 includes a plurality of nozzles that eject processing liquid toward the substrate W held by the spin chuck 10 . The plurality of nozzles includes a chemical liquid nozzle 31 that discharges a chemical liquid toward the upper surface of the substrate W, a rinse liquid nozzle 35 that discharges a rinse liquid toward the upper surface of the substrate W, and a pre-drying treatment liquid toward the upper surface of the substrate W. and a replacement liquid nozzle 43 for ejecting a replacement liquid toward the upper surface of the substrate W. As shown in FIG.

The chemical liquid nozzle 31 may be a scan nozzle horizontally movable within the chamber 4 or a fixed nozzle fixed to the partition wall 5 of the chamber 4 . The same applies to the rinse liquid nozzle 35 , the pre-drying treatment liquid nozzle 39 , and the replacement liquid nozzle 43 . In FIG. 2, the chemical liquid nozzle 31, the rinse liquid nozzle 35, the pre-drying treatment liquid nozzle 39, and the replacement liquid nozzle 43 are scan nozzles, and four nozzle moving units corresponding to these four nozzles are provided. shows an example.

The chemical nozzle 31 is connected to a chemical pipe 32 that guides the chemical to the chemical nozzle 31 . When the chemical liquid valve 33 interposed in the chemical liquid pipe 32 is opened, the chemical liquid is continuously discharged downward from the discharge port of the chemical liquid nozzle 31 . The chemical liquid discharged from the chemical liquid nozzle 31 includes sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid, ammonia water, hydrogen peroxide water, organic acids (eg, citric acid, oxalic acid, etc.), organic alkalis (eg, TMAH: tetramethylammonium hydroxide, etc.), a surfactant, and a corrosion inhibitor, or other liquids.

Although not shown, the chemical valve 33 includes a valve body provided with an internal channel through which the chemical flows and an annular valve seat surrounding the internal channel, a valve body movable with respect to the valve seat, and a valve body. An actuator is included to move the valve disc between a closed position in contact with the valve seat and an open position in which the valve disc is spaced from the valve seat. The same applies to other valves. The actuator may be a pneumatic actuator, an electric actuator, or an actuator other than these. The control device 3 opens and closes the chemical valve 33 by controlling the actuator.

The chemical liquid nozzle 31 is connected to a nozzle moving unit 34 that moves the chemical liquid nozzle 31 in at least one of the vertical direction and the horizontal direction. The nozzle moving unit 34 moves the chemical solution between a processing position where the chemical solution discharged from the chemical solution nozzle 31 is supplied to the upper surface of the substrate W and a standby position where the chemical solution nozzle 31 is positioned around the processing cup 21 in plan view. Move the nozzle 31 horizontally.

The rinse liquid nozzle 35 is connected to a rinse liquid pipe 36 that guides the rinse liquid to the rinse liquid nozzle 35 . When the rinse liquid valve 37 interposed in the rinse liquid pipe 36 is opened, the rinse liquid is continuously discharged downward from the discharge port of the rinse liquid nozzle 35 . The rinse liquid discharged from the rinse liquid nozzle 35 is, for example, pure water (deionized water: DIW). The rinse liquid may be any one of carbonated water, electrolytic ion water, hydrogen water, ozone water, and diluted hydrochloric acid water (for example, about 10 to 100 ppm).

The rinse liquid nozzle 35 is connected to a nozzle moving unit 38 that moves the rinse liquid nozzle 35 in at least one of the vertical direction and the horizontal direction. The nozzle moving unit 38 has a processing position where the rinse liquid discharged from the rinse liquid nozzle 35 is supplied to the upper surface of the substrate W, and a standby position where the rinse liquid nozzle 35 is positioned around the processing cup 21 in plan view. The rinse liquid nozzle 35 is horizontally moved between them.

The pre-drying treatment liquid nozzle 39 is connected to a pre-drying treatment liquid pipe 40 that guides the treatment liquid to the pre-drying treatment liquid nozzle 39 . When the pre-drying treatment liquid valve 41 interposed in the pre-drying treatment liquid pipe 40 is opened, the pre-drying treatment liquid is continuously discharged downward from the outlet of the pre-drying treatment liquid nozzle 39 . Similarly, the substituting liquid nozzle 43 is connected to a substituting liquid pipe 44 that guides the substituting liquid to the substituting liquid nozzle 43 . When the substitution liquid valve 45 interposed in the substitution liquid pipe 44 is opened, the substitution liquid is continuously discharged downward from the discharge port of the substitution liquid nozzle 43 .

The drying pretreatment liquid is a solution containing a sublimable substance corresponding to a solute and a solvent that dissolves with the sublimable substance. The sublimable substance may be a substance that changes from a solid to a gas at normal temperature (synonymous with room temperature) or normal pressure (the pressure in the substrate processing apparatus 1, for example, 1 atmosphere or a value in the vicinity thereof) without going through a liquid state. . The solvent may be such a substance, or may be a substance other than this. In other words, the pre-drying treatment liquid may contain two or more substances that change from solid to gas at room temperature or pressure without going through a liquid state.

Examples of sublimable substances include alcohols such as 2-methyl-2-propanol (also known as tert-butyl alcohol, t-butyl alcohol, tertiary butyl alcohol) and cyclohexanol, fluorocarbon compounds, 1,3, Any one of 5-trioxane (alias: metaformaldehyde), camphor (alias: camphor, camphor), naphthalene, iodine, and cyclohexane, or other substances may be used.

Solvents include, for example, pure water, IPA, HFE (hydrofluoroether), acetone, PGMEA (propylene glycol monomethyl ether acetate), PGEE (propylene glycol monoethyl ether, 1-ethoxy-2-propanol), ethylene glycol, and hydro At least one selected from the group consisting of fluorocarbons (hydrofluorocarbons) may be used.

An example in which the sublimable substance is camphor and the solvent is one of IPA, acetone, and PGEE will be described below. The vapor pressure of IPA is higher than that of camphor. Similarly, the vapor pressure of acetone and PGEE is higher than that of camphor. The vapor pressure of acetone is higher than that of IPA, which is higher than that of PGEE. The freezing point of camphor (the freezing point at 1 atmosphere; the same shall apply hereinafter) is 175 to 177°C. Whether the solvent is IPA, acetone, or PGEE, the freezing point of camphor is higher than the boiling point of the solvent. The freezing point of camphor is higher than that of the dry pretreatment liquid. The freezing point of the pre-drying treatment liquid is lower than room temperature (23° C. or a value in the vicinity thereof). The substrate processing apparatus 1 is arranged in a clean room maintained at room temperature. Therefore, the pre-drying treatment liquid can be kept liquid without heating the pre-drying treatment liquid. The freezing point of the pre-drying treatment liquid may be room temperature or higher.

As will be described later, the replacement liquid is supplied to the upper surface of the substrate W covered with the liquid film of the rinse liquid, and the pre-drying treatment liquid is supplied to the upper surface of the substrate W covered with the liquid film of the replacement liquid. The replacement liquid is a liquid that dissolves with both the rinse liquid and the pre-drying liquid. Substitution liquids are, for example, IPA or HFE. The substitution liquid may be a mixed liquid of IPA and HFE, or may contain at least one of IPA and HFE and other components. IPA and HFE are liquids that are soluble with both water and fluorocarbon compounds.

When the replacement liquid is supplied to the upper surface of the substrate W covered with the liquid film of the rinse liquid, most of the rinse liquid on the substrate W is washed away by the replacement liquid and discharged from the substrate W. FIG. A small amount of the remaining rinsing liquid dissolves in the replacement liquid and diffuses into the replacement liquid. The diffused rinse liquid is discharged from the substrate W together with the replacement liquid. Therefore, the rinse liquid on the substrate W can be efficiently replaced with the replacement liquid. For the same reason, the replacement liquid on the substrate W can be efficiently replaced with the pre-drying treatment liquid. Thereby, the rinse liquid contained in the pre-drying treatment liquid on the substrate W can be reduced.

The pre-drying treatment liquid nozzle 39 is connected to a nozzle moving unit 42 that moves the pre-drying treatment liquid nozzle 39 in at least one of the vertical direction and the horizontal direction. The nozzle moving unit 42 has a processing position where the pre-drying treatment liquid discharged from the pre-drying treatment liquid nozzle 39 is supplied to the upper surface of the substrate W, and a position where the pre-drying treatment liquid nozzle 39 is positioned around the processing cup 21 in plan view. The pre-drying treatment liquid nozzle 39 is moved horizontally between the standby position where the

Similarly, the replacement liquid nozzle 43 is connected to a nozzle moving unit 46 that moves the replacement liquid nozzle 43 in at least one of vertical and horizontal directions. The nozzle moving unit 46 has a processing position where the replacement liquid discharged from the replacement liquid nozzle 43 is supplied to the upper surface of the substrate W, and a standby position where the replacement liquid nozzle 43 is positioned around the processing cup 21 in plan view. The replacement liquid nozzle 43 is horizontally moved between them.

The processing unit 2 includes a blocking member 51 arranged above the spin chuck 10 . FIG. 2 shows an example in which the blocking member 51 is a disk-shaped blocking plate. The blocking member 51 includes a disk portion 52 horizontally arranged above the spin chuck 10 . The blocking member 51 is horizontally supported by a cylindrical support shaft 53 extending upward from the central portion of the disk portion 52 . The centerline of the disk portion 52 is arranged on the rotation axis A1 of the substrate W. As shown in FIG. The lower surface of the disc portion 52 corresponds to the lower surface 51L of the blocking member 51 . A lower surface 51L of the blocking member 51 is a surface facing the upper surface of the substrate W. As shown in FIG. The lower surface 51L of the blocking member 51 is parallel to the upper surface of the substrate W and has an outer diameter equal to or larger than the diameter of the substrate W. As shown in FIG.

The blocking member 51 is connected to a blocking member elevating unit 54 that vertically moves the blocking member 51 up and down. The blocking member elevating unit 54 positions the blocking member 51 at any position from the upper position (the position shown in FIG. 2) to the lower position. The lower position is a close position where the lower surface 51L of the shielding member 51 approaches the upper surface of the substrate W to a height at which the scanning nozzle such as the chemical nozzle 31 cannot enter between the substrate W and the shielding member 51 . The upper position is a separated position where the blocking member 51 is retracted to a height at which the scan nozzle can enter between the blocking member 51 and the substrate W. FIG.

The plurality of nozzles includes a central nozzle 55 that downwardly discharges a processing fluid such as a processing liquid or a processing gas through an upper central opening 61 opened at the center of the lower surface 51L of the blocking member 51 . The central nozzle 55 extends vertically along the rotation axis A1. The central nozzle 55 is arranged in a through-hole vertically penetrating the central portion of the blocking member 51 . The inner peripheral surface of the blocking member 51 surrounds the outer peripheral surface of the central nozzle 55 with a gap in the radial direction (direction orthogonal to the rotation axis A1). The center nozzle 55 moves up and down together with the blocking member 51 . A discharge port of the central nozzle 55 for discharging the processing liquid is arranged above the upper central opening 61 of the blocking member 51 .

The center nozzle 55 is connected to an upper gas pipe 56 that guides inert gas to the center nozzle 55 . The substrate processing apparatus 1 may include an upper temperature controller 59 that heats or cools the inert gas discharged from the center nozzle 55 . When the upper gas valve 57 interposed in the upper gas pipe 56 is opened, the inert gas flows through the outlet of the central nozzle 55 at a flow rate corresponding to the degree of opening of the flow control valve 58 that changes the flow rate of the inert gas. is discharged continuously downward from the The inert gas discharged from the central nozzle 55 is nitrogen gas. The inert gas may be gas other than nitrogen gas, such as helium gas or argon gas.

The inner peripheral surface of the blocking member 51 and the outer peripheral surface of the center nozzle 55 form a cylindrical upper gas flow path 62 extending vertically. The upper gas flow path 62 is connected to an upper gas pipe 63 that guides the inert gas to the upper central opening 61 of the blocking member 51 . The substrate processing apparatus 1 may include an upper temperature controller 66 that heats or cools the inert gas discharged from the upper central opening 61 of the blocking member 51 . When the upper gas valve 64 interposed in the upper gas pipe 63 is opened, the inert gas flows at the upper center of the blocking member 51 at a flow rate corresponding to the opening degree of the flow control valve 65 that changes the flow rate of the inert gas. It is continuously discharged downward from the opening 61 . The inert gas discharged from the upper central opening 61 of the blocking member 51 is nitrogen gas. The inert gas may be gas other than nitrogen gas, such as helium gas or argon gas.

The plurality of nozzles includes a lower surface nozzle 71 that discharges the processing liquid toward the central portion of the lower surface of the substrate W. As shown in FIG. The lower surface nozzle 71 includes a nozzle disk portion arranged between the upper surface 12u of the spin base 12 and the lower surface of the substrate W, and a nozzle cylindrical portion extending downward from the nozzle disk portion. The discharge port of the lower surface nozzle 71 is open at the center of the upper surface of the nozzle disk portion. When the substrate W is held by the spin chuck 10, the ejection port of the lower surface nozzle 71 faces the central portion of the lower surface of the substrate W vertically.

The bottom nozzle 71 is connected to a heating fluid pipe 72 that guides hot water (pure water having a temperature higher than room temperature), which is an example of a heating fluid, to the bottom nozzle 71 . Pure water supplied to the lower surface nozzle 71 is heated by a lower heater 75 interposed in the heating fluid pipe 72 . When the heating fluid valve 73 interposed in the heating fluid pipe 72 is opened, the hot water flows continuously upward from the discharge port of the lower surface nozzle 71 at a flow rate corresponding to the degree of opening of the flow control valve 74 that changes the flow rate of the hot water. is ejected. As a result, hot water is supplied to the lower surface of the substrate W. As shown in FIG.

The lower surface nozzle 71 is further connected to a cooling fluid pipe 76 that guides cold water (pure water having a temperature lower than room temperature), which is an example of a cooling fluid, to the lower surface nozzle 71 . Pure water supplied to the lower surface nozzle 71 is cooled by a cooler 79 interposed in the cooling fluid pipe 76 . When the cooling fluid valve 77 interposed in the cooling fluid pipe 76 is opened, the cold water flows continuously upward from the discharge port of the lower surface nozzle 71 at a flow rate corresponding to the opening degree of the flow control valve 78 that changes the flow rate of the cold water. is ejected. Cold water is thereby supplied to the lower surface of the substrate W. As shown in FIG.

The outer peripheral surface of the lower surface nozzle 71 and the inner peripheral surface of the spin base 12 form a tubular lower gas flow path 82 extending vertically. The lower gas channel 82 includes a lower central opening 81 that opens at the central portion of the upper surface 12 u of the spin base 12 . The lower gas flow path 82 is connected to a lower gas pipe 83 that guides the inert gas to the lower central opening 81 of the spin base 12 . The substrate processing apparatus 1 may include a lower temperature controller 86 that heats or cools the inert gas discharged from the lower central opening 81 of the spin base 12 . When the lower gas valve 84 interposed in the lower gas pipe 83 is opened, the inert gas is supplied to the lower center of the spin base 12 at a flow rate corresponding to the opening of the flow control valve 85 that changes the flow rate of the inert gas. It is continuously discharged upward from the opening 81 .

The inert gas discharged from the lower central opening 81 of the spin base 12 is nitrogen gas. The inert gas may be gas other than nitrogen gas, such as helium gas or argon gas. When the lower central opening 81 of the spin base 12 discharges nitrogen gas while the substrate W is held on the spin chuck 10, the nitrogen gas flows between the lower surface of the substrate W and the upper surface 12u of the spin base 12 in all directions. flow radially into Thereby, the space between the substrate W and the spin base 12 is filled with nitrogen gas.

Next, the pre-drying treatment liquid supply unit will be described.
FIG. 3 is a schematic diagram showing a pre-drying treatment liquid supply unit provided in the substrate processing apparatus 1. As shown in FIG.
The substrate processing apparatus 1 includes a pre-drying treatment liquid supply unit that supplies the pre-drying treatment liquid to the pre-drying treatment liquid nozzles 39 through the pre-drying treatment liquid pipe 40 .
The pre-drying treatment liquid supply unit includes a first tank 87A that stores the pre-drying treatment liquid, a first circulation pipe 88A that circulates the pre-drying treatment liquid in the first tank 87A, and a pre-drying treatment liquid in the first tank 87A. A first pump 89A for sending the liquid to the first circulation pipe 88A and a first individual pipe 90A for guiding the pre-drying treatment liquid in the first circulation pipe 88A to the pre-drying treatment liquid pipe 40 are included. The pre-drying treatment liquid supply unit further includes a first on-off valve 91A for opening and closing the inside of the first individual pipe 90A, and a flow rate of the pre-drying treatment liquid supplied from the first individual pipe 90A to the pre-drying treatment liquid pipe 40. and the first flow control valve 92A to be changed.

The pre-drying treatment liquid supply unit includes a second tank 87B that stores the pre-drying treatment liquid, a second circulation pipe 88B that circulates the pre-drying treatment liquid in the second tank 87B, and a pre-drying treatment liquid in the second tank 87B. A second pump 89B for sending the liquid to the second circulation pipe 88B and a second individual pipe 90B for guiding the pre-drying treatment liquid in the second circulation pipe 88B to the pre-drying treatment liquid pipe 40 are included. The pre-drying treatment liquid supply unit further includes a second on-off valve 91B for opening and closing the inside of the second individual pipe 90B, and a flow rate of the pre-drying treatment liquid supplied from the second individual pipe 90B to the pre-drying treatment liquid pipe 40. and a variable second flow control valve 92B.

The concentration of the pre-drying treatment liquid in the first tank 87A (concentration of the sublimable substance contained in the pre-drying treatment liquid) is different from the concentration of the pre-drying treatment liquid in the second tank 87B. Therefore, when the first opening/closing valve 91A and the second opening/closing valve 91B are opened, the pre-drying treatment liquids having different densities are mixed in the pre-drying treatment liquid pipe 40, and the uniformly mixed pre-drying treatment liquids are mixed before drying. It is discharged from the processing liquid nozzle 39 . Further, when the degree of opening of at least one of the first flow control valve 92A and the second flow control valve 92B is changed, the concentration of the pre-drying treatment liquid discharged from the pre-drying treatment liquid nozzle 39 is changed.

The control device 3 opens the first opening/closing valve 91A, the second opening/closing valve 91B, the first flow rate adjustment valve 92A, and the second flow rate adjustment valve 92B based on the concentration of the pre-drying treatment liquid specified in a recipe to be described later. set the degree. For example, when the concentration of the pre-drying treatment liquid specified in the recipe matches the concentration of the pre-drying treatment liquid in the first tank 87A, the first on-off valve 91A is opened and the second on-off valve 91B is closed. Closed. If the concentration of the pre-drying treatment liquid specified in the recipe is between the concentration of the pre-drying treatment liquid in the first tank 87A and the concentration of the pre-drying treatment liquid in the second tank 87B, the first Both the opening/closing valve 91A and the second opening/closing valve 91B are opened, and the opening degrees of the first flow control valve 92A and the second flow control valve 92B are adjusted. As a result, the concentration of the pre-drying treatment liquid ejected from the pre-drying treatment liquid nozzle 39 approaches the concentration of the pre-drying treatment liquid specified by the recipe.

FIG. 4 is a block diagram showing the hardware of the control device 3. As shown in FIG.
The control device 3 is a computer including a computer main body 3a and a peripheral device 3b connected to the computer main body 3a. The computer main body 3a includes a CPU 93 (central processing unit) that executes various commands, and a main storage device 94 that stores information. The peripheral device 3b includes an auxiliary storage device 95 that stores information such as the program P, a reading device 96 that reads information from the removable medium M, and a communication device 97 that communicates with other devices such as a host computer.

The control device 3 is connected to the input device 98 and the display device 99 . The input device 98 is operated when an operator such as a user or a person in charge of maintenance inputs information to the substrate processing apparatus 1 . Information is displayed on the screen of the display device 99 . The input device 98 may be one of a keyboard, pointing device, and touch panel, or may be a device other than these. A touch panel display that serves as both the input device 98 and the display device 99 may be provided in the substrate processing apparatus 1 .

The CPU 93 executes the program P stored in the auxiliary storage device 95 . The program P in the auxiliary storage device 95 may be pre-installed in the control device 3, or may be sent from the removable medium M to the auxiliary storage device 95 through the reading device 96, It may be sent from an external device such as a host computer to the auxiliary storage device 95 through the communication device 97 .

The auxiliary storage device 95 and removable media M are nonvolatile memories that retain data even when power is not supplied. Auxiliary storage device 95 is, for example, a magnetic storage device such as a hard disk drive. The removable medium M is, for example, an optical disk such as a compact disk or a semiconductor memory such as a memory card. The removable medium M is an example of a computer-readable recording medium on which the program P is recorded. The removable medium M is a tangible recording medium that is not temporary.

Auxiliary storage device 95 stores a plurality of recipes. The recipe is information that defines the processing content, processing conditions, and processing procedure of the substrate W. FIG. The plurality of recipes differ from each other in at least one of the processing content of the substrate W, the processing conditions, and the processing procedure. The control device 3 controls the substrate processing apparatus 1 so that the substrate W is processed according to the recipe specified by the host computer. Each of the following steps is executed by controlling the substrate processing apparatus 1 by the controller 3 . In other words, the controller 3 is programmed to carry out the following steps.

Next, an example of processing of the substrate W according to the first embodiment will be described.
The substrate W to be processed is, for example, a semiconductor wafer such as a silicon wafer. The surface of the substrate W corresponds to a device forming surface on which devices such as transistors and capacitors are formed. The substrate W may be the substrate W having the pattern P1 (see FIG. 6A) formed on the surface of the substrate W, which is the pattern forming surface, or the substrate W having no pattern P1 formed on the surface of the substrate W. may In the latter case, the pattern P1 may be formed in the chemical solution supply step, which will be described later.

FIG. 5 is a process chart for explaining an example of processing of the substrate W according to the first embodiment. 6A to 6C are schematic diagrams showing the state of the substrate W when the substrate W shown in FIG. 5 is being processed.
In the following, reference is made to FIGS. 2 and 5. FIG. 6A to 6C will be referred to as appropriate.
When the substrate processing apparatus 1 processes the substrate W, a loading step (step S1 in FIG. 5) of loading the substrate W into the chamber 4 is performed.

Specifically, the center robot CR (Fig. 1) moves the hand H1 into the chamber 4 while supporting the substrate W with the hand H1. Then, the center robot CR places the substrate W on the hand H1 on the plurality of chuck pins 11 with the surface of the substrate W facing upward. After that, a plurality of chuck pins 11 are pressed against the outer peripheral surface of the substrate W, and the substrate W is gripped. After placing the substrate W on the spin chuck 10 , the center robot CR withdraws the hand H<b>1 from the interior of the chamber 4 .

Next, the upper gas valve 64 and the lower gas valve 84 are opened, and the upper central opening 61 of the blocking member 51 and the lower central opening 81 of the spin base 12 start discharging nitrogen gas. Thereby, the space between the substrate W and the blocking member 51 is filled with nitrogen gas. Similarly, the space between the substrate W and the spin base 12 is filled with nitrogen gas. Meanwhile, the guard lifting unit 27 lifts at least one guard 24 from the lower position to the upper position. Thereafter, the spin motor 14 is driven to start rotating the substrate W (step S2 in FIG. 5). This causes the substrate W to rotate at the liquid supply speed.

Next, a chemical liquid supply step (step S3 in FIG. 5) is performed for supplying the chemical liquid to the upper surface of the substrate W to form a liquid film of the chemical liquid covering the entire upper surface of the substrate W. FIG.
Specifically, the nozzle moving unit 34 moves the chemical liquid nozzle 31 from the standby position to the processing position in a state where the blocking member 51 is positioned at the upper position and at least one guard 24 is positioned at the upper position. . After that, the chemical valve 33 is opened and the chemical nozzle 31 starts discharging the chemical. After a predetermined period of time has passed since the chemical valve 33 was opened, the chemical valve 33 is closed and the discharge of the chemical is stopped. After that, the nozzle moving unit 34 moves the liquid medicine nozzle 31 to the standby position.

The chemical liquid discharged from the chemical liquid nozzle 31 collides with the upper surface of the substrate W rotating at the liquid supply speed, and then flows outward along the upper surface of the substrate W due to centrifugal force. Therefore, the chemical solution is supplied to the entire upper surface of the substrate W, and a liquid film of the chemical solution covering the entire upper surface of the substrate W is formed. When the chemical liquid nozzle 31 is discharging the chemical liquid, the nozzle moving unit 34 may move the liquid landing position of the chemical liquid on the upper surface of the substrate W so that the liquid landing position passes through the central portion and the outer peripheral portion, The liquid landing position may be stationary at the central portion.

Next, a rinse liquid supply step (step S4 in FIG. 5) is performed in which pure water, which is an example of a rinse liquid, is supplied to the upper surface of the substrate W to wash away the chemical liquid on the substrate W. FIG.
Specifically, the nozzle moving unit 38 moves the rinse liquid nozzle 35 from the standby position to the processing position in a state where the blocking member 51 is positioned at the upper position and at least one guard 24 is positioned at the upper position. Let After that, the rinse liquid valve 37 is opened, and the rinse liquid nozzle 35 starts discharging the rinse liquid. The guard elevating unit 27 may vertically move at least one guard 24 to switch the guard 24 that receives the liquid discharged from the substrate W before the pure water discharge is started. After a predetermined period of time has passed since the rinse liquid valve 37 was opened, the rinse liquid valve 37 is closed and the discharge of the rinse liquid is stopped. After that, the nozzle moving unit 38 moves the rinse liquid nozzle 35 to the standby position.

The pure water discharged from the rinse liquid nozzle 35 collides with the upper surface of the substrate W rotating at the liquid supply speed, and then flows outward along the upper surface of the substrate W due to centrifugal force. The chemical liquid on the substrate W is replaced with pure water discharged from the rinse liquid nozzle 35 . As a result, a pure water liquid film covering the entire upper surface of the substrate W is formed. When the rinse liquid nozzle 35 is discharging pure water, the nozzle moving unit 38 moves the pure water landing position on the upper surface of the substrate W so that the pure water landing position passes through the central portion and the outer peripheral portion. Alternatively, the liquid landing position may be stationary at the central portion.

Next, a substitution liquid supply step (step S5 in FIG. 5) is performed to supply a substitution liquid that dissolves with both the rinse liquid and the pre-drying treatment liquid to the upper surface of the substrate W to substitute the pure water on the substrate W with the substitution liquid. will be
Specifically, the nozzle moving unit 46 moves the replacement liquid nozzle 43 from the waiting position to the processing position while the blocking member 51 is positioned at the upper position and at least one guard 24 is positioned at the upper position. Let After that, the substitution liquid valve 45 is opened, and the substitution liquid nozzle 43 starts discharging the substitution liquid. The guard elevating unit 27 may vertically move at least one guard 24 in order to switch the guard 24 that receives the liquid discharged from the substrate W before the discharge of the replacement liquid is started. After a predetermined period of time has passed since the substitution liquid valve 45 was opened, the substitution liquid valve 45 is closed and the discharge of the substitution liquid is stopped. After that, the nozzle moving unit 46 moves the replacement liquid nozzle 43 to the standby position.

The replacement liquid discharged from the replacement liquid nozzle 43 collides with the upper surface of the substrate W rotating at the liquid supply speed, and then flows outward along the upper surface of the substrate W due to centrifugal force. The pure water on the substrate W is replaced with the replacement liquid discharged from the replacement liquid nozzle 43 . As a result, a liquid film of the replacement liquid covering the entire upper surface of the substrate W is formed. When the substituting liquid nozzle 43 is discharging the substituting liquid, the nozzle moving unit 46 may move the substituting liquid landing position on the upper surface of the substrate W so that the substituting liquid landing position passes through the central portion and the outer peripheral portion. Alternatively, the liquid landing position may be stationary at the central portion. Further, after the liquid film of the replacement liquid covering the entire upper surface of the substrate W is formed, the substrate W is moved at a paddle speed (for example, a speed of 20 rpm or less exceeding 0) while stopping the ejection of the replacement liquid from the replacement liquid nozzle 43 . You can also rotate with .

Next, a pre-drying treatment liquid supply step (step S6 in FIG. 5) is performed to supply the pre-drying treatment liquid to the upper surface of the substrate W to form a liquid film of the pre-drying treatment liquid on the substrate W. FIG.
Specifically, the blocking member 51 is positioned at the upper position and at least one guard 24 is positioned at the upper position, and the nozzle moving unit 42 moves the pre-drying treatment liquid nozzle 39 from the waiting position to the processing position. move to After that, the pre-drying treatment liquid valve 41 is opened, and the pre-drying treatment liquid nozzle 39 starts discharging the pre-drying treatment liquid. The guard elevating unit 27 may vertically move at least one guard 24 in order to switch the guard 24 that receives the liquid discharged from the substrate W before the discharge of the pre-drying treatment liquid is started. When a predetermined time has passed since the pre-drying treatment liquid valve 41 was opened, the pre-drying treatment liquid valve 41 is closed, and the discharge of the pre-drying treatment liquid is stopped. After that, the nozzle moving unit 42 moves the pre-drying treatment liquid nozzle 39 to the standby position.

The pre-drying treatment liquid discharged from the pre-drying treatment liquid nozzle 39 collides with the upper surface of the substrate W rotating at the liquid supply speed, and then flows outward along the upper surface of the substrate W due to centrifugal force. The replacement liquid on the substrate W is replaced with the pre-drying treatment liquid discharged from the pre-drying treatment liquid nozzle 39 . As a result, a liquid film of the pre-drying treatment liquid covering the entire upper surface of the substrate W is formed. When the pre-drying treatment liquid nozzle 39 is discharging the pre-drying treatment liquid, the nozzle moving unit 42 lands the pre-drying treatment liquid on the upper surface of the substrate W so that the position where the pre-drying treatment liquid lands passes through the central portion and the outer peripheral portion. The position may be moved, or the liquid landing position may be stationary at the central portion.

Next, part of the pre-drying treatment liquid on the substrate W is removed, and the pre-drying treatment liquid on the substrate W is maintained while the entire upper surface of the substrate W is covered with the liquid film of the pre-drying treatment liquid. A film thickness reduction step (step S7 in FIG. 5) is performed to reduce the film thickness (thickness of the liquid film).
Specifically, the spin motor 14 maintains the rotation speed of the substrate W at the film thickness reduction speed while the blocking member 51 is positioned at the lower position. The film thickness reduction rate may be equal to or different from the liquid supply rate. The pre-drying treatment liquid on the substrate W is discharged outward from the substrate W by centrifugal force even after the ejection of the pre-drying treatment liquid is stopped. Therefore, the thickness of the liquid film of the pre-drying treatment liquid on the substrate W is reduced. When the pre-drying treatment liquid on the substrate W is discharged to some extent, the amount of the pre-drying treatment liquid discharged from the substrate W per unit time is reduced to zero or substantially zero. As a result, the thickness of the liquid film of the pre-drying treatment liquid on the substrate W is stabilized at a value corresponding to the substrate W rotation speed.

Next, a solidified body forming step (step S8 in FIG. 5) is performed to solidify the pre-drying treatment liquid on the substrate W to form a solidified body 101 (see FIG. 6B) containing a sublimable substance on the substrate W. .
Specifically, the spin motor 14 maintains the rotation speed of the substrate W at the solidified body formation speed while the blocking member 51 is positioned at the lower position. The coagulum formation rate may be equal to or different from the liquid feed rate. Furthermore, the upper gas valve 57 is opened to cause the central nozzle 55 to start discharging nitrogen gas. In addition to or instead of opening the upper gas valve 57 , the degree of opening of the flow control valve 65 may be changed to increase the flow rate of nitrogen gas discharged from the upper central opening 61 of the blocking member 51 .

When the substrate W starts to rotate at the solidified body forming speed, the pre-drying treatment liquid evaporates, and part of the pre-drying treatment liquid on the substrate W evaporates. Since the vapor pressure of the solvent is higher than the vapor pressure of the sublimable substance corresponding to the solute, the solvent evaporates at an evaporation rate greater than that of the sublimable substance. Therefore, the film thickness of the pre-drying treatment liquid gradually decreases while the concentration of the sublimable substance gradually increases. The freezing point of the pre-drying treatment liquid increases as the concentration of the sublimable substance increases. As can be seen by comparing FIGS. 6A and 6B, when the freezing point of the pre-drying treatment liquid reaches the temperature of the pre-drying treatment liquid, the pre-drying treatment liquid begins to solidify, and corresponds to a solidified film covering the entire upper surface of the substrate W. A solid 101 is formed.

Next, a sublimation step (step S9 in FIG. 5) is performed in which the solidified body 101 on the substrate W is sublimated and removed from the upper surface of the substrate W. FIG.
Specifically, the spin motor 14 maintains the rotation speed of the substrate W at the sublimation speed while the blocking member 51 is positioned at the lower position. The sublimation rate may be equal to or different from the liquid feed rate. Furthermore, when the upper gas valve 57 is closed, the upper gas valve 57 is opened to cause the center nozzle 55 to start discharging nitrogen gas. In addition to or instead of opening the upper gas valve 57 , the degree of opening of the flow control valve 65 may be changed to increase the flow rate of nitrogen gas discharged from the upper central opening 61 of the blocking member 51 . When a predetermined time has elapsed since the substrate W started rotating at the sublimation speed, the spin motor 14 stops and the substrate W stops rotating (step S10 in FIG. 5).

When the rotation of the substrate W at the sublimation speed or the like is started, sublimation of the solidified material 101 on the substrate W starts, and gas containing a sublimable substance is generated from the solidified material 101 on the substrate W. FIG. The gas (gas containing a sublimable substance) generated from the solidified body 101 radially flows through the space between the substrate W and the blocking member 51 and is discharged from above the substrate W. FIG. Then, after a certain amount of time has passed since the sublimation started, all the solidified bodies 101 are removed from the substrate W, as shown in FIG. 6C.

Next, an unloading step (step S11 in FIG. 5) of unloading the substrate W from the chamber 4 is performed.
Specifically, the blocking member lifting unit 54 lifts the blocking member 51 to the upper position, and the guard lifting unit 27 lowers all the guards 24 to the lower position. Furthermore, the upper gas valve 64 and the lower gas valve 84 are closed, and the upper central opening 61 of the blocking member 51 and the lower central opening 81 of the spin base 12 stop discharging nitrogen gas. After that, the center robot CR makes the hand H1 enter the chamber 4 . After the plurality of chuck pins 11 release the grip of the substrate W, the center robot CR supports the substrate W on the spin chuck 10 with the hand H1. After that, the center robot CR withdraws the hand H1 from the inside of the chamber 4 while supporting the substrate W with the hand H1. Thereby, the processed substrate W is unloaded from the chamber 4 .

FIG. 7 is a graph showing an example of an image of how the thickness of the liquid film of the pre-drying treatment liquid on the substrate W decreases due to evaporation of the solvent.
In FIG. 7, the solid line indicates the thickness of the liquid film when the initial concentration of the sublimable substance is the reference concentration, and the dashed-dotted line indicates the thickness of the liquid film when the initial concentration of the sublimable substance is low. , the thickness of the liquid film when the initial concentration of the sublimable substance is high is indicated by a chain double-dashed line. A reference concentration is a concentration that is higher than the low concentration and lower than the high concentration. The initial concentration of the sublimable substance means the concentration of the sublimable substance in the pre-drying treatment liquid before the substrate W is supplied.

If the concentration of the sublimable substance in the pre-drying treatment liquid is the same, the thickness T1 (see FIG. 6B) of the solidified body 101 formed on the substrate W is the film thickness of the pre-drying treatment liquid before forming the solidified body 101. It depends on the thickness (thickness of the liquid film). That is, when the film thickness of the pre-drying treatment liquid is large, a thick solidified body 101 is formed, and when the film thickness of the pre-drying treatment liquid is small, a thin solidified body 101 is formed. Therefore, by changing the film thickness of the pre-drying treatment liquid, the thickness T1 of the solidified body 101 can be changed.

When the rotation speed of the substrate W is increased, the pre-drying treatment liquid is discharged from the substrate W by centrifugal force, and the film thickness of the pre-drying treatment liquid on the substrate W is reduced. At this time, if the gas is discharged toward the upper surface of the substrate W, the pressure of the gas is applied to the pre-drying treatment liquid, and the film thickness of the pre-drying treatment liquid on the substrate W is further reduced. However, when the film thickness is reduced to a certain extent, the flow velocity in the liquid film is extremely reduced, so even if the rotation speed or gas flow rate is increased, the film thickness does not change significantly. Conversely, if the rotation speed or gas flow rate is too high, the upper surface of the substrate W will be partially exposed from the liquid film.

Therefore, even if the rotation speed of the substrate W or the flow rate of the gas is changed, the film thickness of the pre-drying treatment liquid before forming the solidified body 101 cannot be extremely thinned, and an extremely thin solidified body 101 is formed. I can't. Therefore, an extremely thin solidified body 101 (for example, a solidified body 101 having a thickness exceeding 0 and 1 μm or less) covering the entire upper surface of the substrate W is formed, or a solidified body is formed within an extremely thin range (for example, a thickness exceeding 0 and 1 μm or less). When changing the thickness T1 of 101, the initial concentration of the sublimable substance must be changed.

In FIG. 7, the film thickness of the dry pretreatment liquid before evaporating the solvent is constant regardless of the initial concentration of the sublimable substance. Further, as shown in FIG. 7, if the temperature of the pretreatment liquid for drying is constant, the concentration of the sublimable substance when precipitation of the solidified body 101 starts is constant regardless of the initial concentration of the sublimable substance. When the solvent is evaporated to form the solidified body 101, the film thickness of the pre-drying treatment liquid gradually decreases while the concentration of the sublimable substance gradually increases. The freezing point of the pre-drying treatment liquid increases as the concentration of the sublimable substance increases. When the freezing point of the pre-drying treatment liquid reaches the temperature of the pre-drying treatment liquid, the pre-drying treatment liquid starts to solidify, and a solidified body 101 is formed on the substrate W. FIG.

As shown in FIG. 7, when the initial concentration of the sublimable substance is the reference concentration, a solidified body 101 having a reference thickness Tr is formed. When the initial concentration of the sublimable substance is low, the amount of the sublimable substance contained in the pre-drying treatment liquid is small, so that the solidified body 101 thinner than the reference thickness Tr is formed. When the initial concentration of the sublimable substance is high, the amount of the sublimable substance contained in the pre-drying treatment liquid is large, so that the solidified body 101 having a thickness greater than the reference thickness Tr is formed. Therefore, by controlling the initial concentration of the sublimable substance, the thickness T1 of the solidified body 101 can be varied within the extremely thin range.

FIG. 8 is a graph showing an example of the relationship between the initial concentration of the sublimable substance and the thickness T1 of the solidified body 101. In FIG. vol % in FIG. 8 indicates volume percent concentration. When the pre-drying treatment liquid changes into the solidified body 101, the color of the substance on the substrate W changes from transparent to opaque. When the film thickness of the transparent dry pretreatment liquid is measured by the spectroscopic interferometry, the measured value changes when the non-transparent solidified body 101 is formed. The value immediately before this change is shown in FIG. 8 as the thickness T1 of the solidified body 101 .

In FIG. 8, when the initial concentration of the sublimable substance is 0.5 vol%, the thickness T1 of the solidified body 101 is about 100 μm, and when the initial concentration of the sublimable substance is 1.23 vol%, the thickness of the solidified body 101 is The thickness T1 was about 200 μm. The initial concentration of the sublimable substance and the thickness T1 of the solidified body 101 are generally in a directly proportional relationship, and as the initial concentration of the sublimable substance increases, the thickness T1 of the solidified body 101 increases at a constant rate. Therefore, by changing the initial concentration of the sublimable substance, the thickness T1 of the solidified body 101 can be changed within a very thin range.

FIG. 9 is a table showing an example of the embedding rate and the collapse rate of the pattern P1 obtained when a plurality of samples in which the pattern P1 having the same shape and intensity was formed was processed while changing the initial concentration of camphor. FIG. 10 is a line graph showing the relationship between the concentration of camphor and the collapse rate of the pattern P1 in FIG.
9 and 10 show the collapse rate of pattern P1 when the sublimable substance is camphor and the solvent is IPA. Measurement conditions 1-1 to 1-13 shown in FIGS. 9 and 10 are the same except for the initial concentration of camphor. wt % in FIG. 9 indicates mass percent concentration. This also applies to other figures such as FIG.

The collapse rate of the pattern P1 is a value obtained by multiplying the ratio of the number of collapsed patterns P1 to the total number of patterns P1 by 100. The embedding rate is a value obtained by multiplying the ratio of the thickness T1 (see FIG. 6B) of the solidified body 101 to the height Hp (see FIG. 6B) of the pattern P1 by 100 times. That is, the embedding rate is obtained by the formula ((thickness T1 of solidified body 101/height Hp of pattern P1)×100).

As shown in measurement condition 1-1 in FIG. 9, when the initial concentration of camphor was 0.52 wt %, the collapse rate of pattern P1 was 83.5%.
As shown in measurement conditions 1-2 in FIG. 9, when the initial concentration of camphor was 0.62 wt %, the collapse rate of pattern P1 was 83.1%.
As shown in measurement conditions 1-3 in FIG. 9, when the initial concentration of camphor was 0.69 wt %, the collapse rate of pattern P1 was 76.2%.

As shown in measurement conditions 1-4 in FIG. 9, when the initial concentration of camphor was 0.78 wt %, the collapse rate of pattern P1 was 36.1%.
As shown in measurement conditions 1-13 in FIG. 9, the collapse rate of pattern P1 was 91.0% when the initial concentration of camphor was 7.76 wt %.
As shown in measurement conditions 1-12 in FIG. 9, the collapse rate of pattern P1 was 91.7% when the initial concentration of camphor was 4.03 wt %.

As shown in measurement conditions 1-11 in FIG. 9, when the initial concentration of camphor was 2.06 wt %, the collapse rate of pattern P1 was 87.0%.
As shown in measurement conditions 1-10 in FIG. 9, when the initial concentration of camphor was 1.55 wt %, the collapse rate of pattern P1 was 46.8%.
As can be seen from FIGS. 9 and 10, when the initial concentration of camphor increases from 0.62 wt % to 0.69 wt %, the collapse rate of pattern P1 decreases (measurement condition 1-2 → measurement condition 1 -3). In addition, when the initial concentration of camphor increased from 0.69 wt % to 0.78 wt %, the collapse rate of pattern P1 decreased sharply (measurement condition 1-3→measurement condition 1-4).

On the other hand, when the initial concentration of camphor decreased from 2.06 wt % to 1.55 wt %, the collapse rate of pattern P1 decreased sharply (measurement condition 1-11→measurement condition 1-10).
Therefore, the initial concentration of camphor is preferably greater than 0.62 wt% and less than 2.06 wt%, more preferably greater than or equal to 0.78 wt% and less than 2.06 wt%.
In the range of initial concentration of camphor above 0.62 wt% and below 2.06 wt%, the collapse rate of pattern P1 is less than 87.0%.

When the initial concentration of camphor is in the range of 0.78 wt % or more and 1.55 wt % or less, the pattern P1 collapse rate is 46.8% or less.
When the initial concentration of camphor is in the range of 0.89 wt% or more and 1.24 wt% or less, the pattern P1 collapse rate is 17.6% or less. The collapse rate for pattern P1 was lowest at 8.32% when the initial concentration of camphor was 0.89 wt%.

Therefore, the initial concentration of camphor may be 0.78 wt% or more and 1.55 wt% or less, or 0.89 wt% or more and 1.24 wt% or less.
FIG. 11 is a line graph showing the relationship between the embedding rate and the collapse rate of the pattern P1 in FIG.
As shown in measurement condition 1-1 in FIG. 9, when the embedding rate was 65%, the collapse rate of pattern P1 was 83.5%.

As shown in measurement conditions 1-2 in FIG. 9, the collapse rate of pattern P1 was 83.1% when the filling rate was 76%.
As shown in measurement conditions 1-3 of FIG. 9, the collapse rate of pattern P1 was 76.2% when the filling rate was 83%.
As shown in measurement conditions 1-4 in FIG. 9, when the embedding rate was 91%, the collapse rate of pattern P1 was 36.1%.

As shown in measurement conditions 1-13 in FIG. 9, the collapse rate of pattern P1 was 91.0% when the filling rate was 797%.
As shown in measurement conditions 1-12 in FIG. 9, the collapse rate of pattern P1 was 91.7% when the filling rate was 418%.
As shown in measurement conditions 1-11 in FIG. 9, the collapse rate of pattern P1 was 87.0% when the filling rate was 219%.

As shown in measurement conditions 1-10 in FIG. 9, the collapse rate of pattern P1 was 46.8% when the filling rate was 168%.
As can be seen from FIGS. 9 and 11, when the embedding rate increases from 76% to 83%, the collapse rate of pattern P1 decreases (measurement condition 1-2→measurement condition 1-3). In addition, when the embedding rate increases from 83% to 91%, the collapse rate of the pattern P1 sharply decreases (measurement condition 1-3→measurement condition 1-4).

On the other hand, when the filling rate decreased from 219% to 168%, the collapse rate of the pattern P1 sharply decreased (measurement condition 1-11→measurement condition 1-10).
Therefore, the embedding rate is preferably more than 76% and less than 219%, more preferably 83% or more and less than 219%.
In the range where the embedding rate exceeds 76% and is less than 219%, the collapse rate of the pattern P1 is less than 87.0%.

When the embedding rate is in the range of 91% or more and 168% or less, the collapse rate of the pattern P1 is 46.8% or less.
When the embedding rate is in the range of 102% or more and 138% or less, the collapse rate of the pattern P1 is 17.6% or less. The collapse rate of pattern P1 was the lowest when the filling rate was 102%, which was 8.32%.

Therefore, the embedding rate may be 91% or more and 168% or less, or may be 102% or more and 138% or less.
As mentioned above, the initial concentration of camphor is preferably greater than 0.62 wt% and less than 2.06 wt%. As shown in FIG. 9, when the initial concentration of camphor is 0.62 wt %, the embedding rate is 76%. When the initial concentration of camphor is 2.06 wt%, the embedding rate is 219%. Thus, in this example, setting the initial concentration of camphor to a value within the preferred range automatically sets the embedding rate to a value within the preferred range.

FIG. 12 is a schematic diagram for explaining the mechanism assumed for the phenomenon that the collapse rate of the pattern P1 increases when the solidified body 101 is too thick. FIG. 13 is a schematic diagram for explaining the mechanism assumed for the phenomenon that the collapse rate of the pattern P1 increases when the solidified body 101 is too thin.
As shown in FIG. 11, if the solidified body 101 is too thick (if the embedding rate is too high), the collapse rate of the pattern P1 increases. Even if the thickness T1 of the solidified body 101 is smaller than the height Hp of the pattern P1, the collapse rate of the pattern P1 may be low. Higher crash rate. Below, the assumed mechanism for these phenomena will be described.

First, a mechanism assumed for the phenomenon that the collapse rate of the pattern P1 increases when the solidified body 101 is too thick will be described.
As the evaporation of IPA contained in the pre-drying treatment liquid progresses, the concentration of camphor in the pre-drying treatment liquid gradually increases, and the freezing point of the pre-drying treatment liquid gradually rises. When the freezing point of the pre-drying treatment liquid reaches the temperature of the pre-drying treatment liquid, the pre-drying treatment liquid starts to solidify, and a solid 101 containing camphor is formed on the substrate W. FIG.

When the embedding rate is 100% or more, that is, when the thickness T1 (see FIG. 6B) of the solidified body 101 is equal to or greater than the height Hp (see FIG. 6B) of the pattern P1, before the solidified body 101 is formed, the pattern The pre-drying treatment liquid exists not only between P1 but also above the pattern P1. On the substrate W such as a semiconductor wafer, since the distance between two adjacent convex patterns P1 is narrow, the freezing point of the pre-drying treatment liquid positioned between the patterns P1 is lowered. Therefore, the freezing point of the drying pretreatment liquid positioned between the patterns P1 is lower than the freezing point of the drying pretreatment liquid positioned above the pattern P1.

If the freezing point of the drying pretreatment liquid positioned above the pattern P1 is higher than the freezing point of the drying pretreatment liquid positioned between the patterns P1, the drying pretreatment liquid will start to solidify at locations other than between the patterns P1. . Specifically, as shown in FIG. 12A, camphor crystal nuclei are located on the surface layer of the pre-drying treatment liquid, that is, in the range from the upper surface (liquid surface) of the pre-drying treatment liquid to the upper surface of the pattern P1. This crystal nucleus gradually grows larger. Then, after a certain amount of time has passed, the entire surface layer of the pre-drying treatment liquid hardens to form a solid 101 .

Here, if the freezing point of the pre-drying treatment liquid positioned between the patterns P1 is lower than the freezing point of the pre-drying treatment liquid positioned above the pattern P1, as shown in FIG. The pre-drying treatment liquid located at the position may not solidify and remain liquid. In this case, the interface between the solid (coagulated body 101) and the liquid (pre-drying treatment liquid) is formed near the pattern P1. FIG. 12(b) shows the situation where an unclear interface of solid and liquid is located between the patterns P1.

Solids and liquids differ from each other in surface free energy. When an unclear interface between the solid (coagulated body 101) and the liquid (drying pretreatment liquid) is positioned between the patterns P1, a force due to the Laplace pressure is applied to the patterns P1. At this time, the force applied to the pattern P1 increases as the solidified body 101 becomes thicker. Therefore, when the solidified body 101 is too thick, the collapse force for collapsing the pattern P1 exceeds the strength of the pattern P1, and the collapse rate of the pattern P1 increases. It is considered that such a mechanism increases the collapse rate of the pattern P1.

Next, a mechanism assumed for the phenomenon that the collapse rate of the pattern P1 is low even when the embedding rate is less than 100% will be described.
When the solidified body 101 is formed, the upper surface (liquid surface) of the pre-drying treatment liquid gradually approaches the lower end of the pattern P1 as the IPA evaporates. When the thickness T1 of the solidified body 101 is significantly smaller than the height Hp of the pattern P1, as shown in FIG. It moves between two adjacent convex patterns P1. That is, the interface between the gas and the liquid (pre-drying treatment liquid) moves between the patterns P1. Therefore, it is considered that a force caused by the surface tension of the pre-drying treatment liquid is applied to the pattern P1, causing the pattern P1 to collapse. Then, as shown in FIG. 13(b), it is considered that the solidified body 101 is formed with the pattern P1 collapsed.

Even if the thickness T1 of the solidified body 101 is slightly smaller than the height Hp of the pattern P1, it is considered that the gas-liquid interface can move between the patterns P1. However, in this case, camphor crystal nuclei have already been formed between the patterns P1, and it is considered that these crystal nuclei have grown to some extent. In this case, the inclination of the pattern P1 is regulated by large crystal nuclei, and the collapse of the pattern P1 is less likely to occur. Due to such a mechanism, even if the thickness T1 of the solidified body 101 is slightly smaller than the height Hp of the pattern P1, the collapse rate of the pattern P1 is considered to decrease.

As described above, if the solidified body 101 is too thick or too thin, the collapse rate of the pattern P1 decreases. In other words, the thickness of the solidified body 101 has an appropriate range for reducing the collapse rate of the pattern P1 on the substrate W after drying. For example, by setting the solidified body 101 to a value within the range described with reference to FIG. 9, the collapse rate of the pattern P1 of the substrate W after drying can be reduced. Thereby, the substrate W can be dried while suppressing the collapse rate of the pattern P1.

Next, measurement results obtained when another sample is used will be described.
14 to 16 are tables showing an example of the collapse rate of patterns P1 obtained when a plurality of samples in which patterns P1 having similar shapes and intensities were formed were processed while changing the initial concentration of camphor.
FIG. 14 shows the collapse rate of pattern P1 when the sublimable substance is camphor and the solvent is IPA, and FIG. 15 shows the collapse rate of pattern P1 when the sublimable substance is camphor and the solvent is acetone. FIG. 16 shows the collapse rate of pattern P1 when the sublimable substance is camphor and the solvent is PGEE.

Measurement conditions 2-1 to 2-5 shown in FIG. 14 are the same except for the initial concentration of camphor. Similarly, in measurement conditions 3-1 to 3-13 shown in FIG. 15, conditions other than the initial concentration of camphor are the same, and in measurement conditions 4-1 to 4-8 shown in FIG. The conditions other than the initial concentration of are the same.
Similar samples were used in the measurements of FIGS. The intensity of the sample pattern P1 used for the measurements of FIGS. 14 to 16 is different from the intensity of the sample pattern P1 used for the measurement of FIG. Therefore, both FIGS. 9 and 14 show the collapse rate of the pattern P1 when the sublimable substance is camphor and the solvent is IPA. , 9 and 14 cannot be simply compared.

FIG. 17 is a line graph showing the relationship between the concentration of camphor and the collapse rate of the pattern P1 in FIG. FIG. 18 is a line graph showing the relationship between the concentration of camphor and the collapse rate of the pattern P1 in FIG. FIG. 19 is a line graph showing the relationship between the concentration of camphor and the collapse rate of the pattern P1 in FIG.
First, with reference to FIGS. 14 and 17, an example of the relationship between the initial concentration of camphor and the collapse rate of the pattern P1 when the solvent is IPA will be described.

As shown in measurement condition 2-1 in FIG. 14, the collapse rate of pattern P1 was 91.7% when the initial concentration of camphor was 0.89 wt %.
As shown in measurement condition 2-2 in FIG. 14, when the initial concentration of camphor was 0.96 wt %, the collapse rate of pattern P1 was 58.4%.
As shown in measurement conditions 2-3 in FIG. 14, when the initial concentration of camphor was 1.13 wt %, the collapse rate of pattern P1 was 37.3.

As shown in measurement conditions 2-4 in FIG. 14, when the initial concentration of camphor was 1.38 wt %, the collapse rate of pattern P1 was 50.6%.
As shown in measurement conditions 2-5 in FIG. 14, the collapse rate of pattern P1 was 95.3% when the initial concentration of camphor was 1.55 wt %.
As can be seen from FIGS. 14 and 17, when the initial concentration of camphor increased from 0.89 wt % to 0.96 wt %, the collapse rate of pattern P1 decreased sharply (measurement condition 2-1 → measurement Condition 2-2). When the initial concentration of camphor decreased from 1.55 wt % to 1.38 wt %, the collapse rate of pattern P1 also decreased sharply (measurement condition 2-5→measurement condition 2-4).

When the initial concentration of camphor is in the range of 0.96 wt % or more and 1.38 wt % or less, the collapse rate of the pattern P1 is 58.4% or less. Therefore, when the solvent is IPA, the initial concentration of camphor is preferably greater than 0.89 wt% and less than 1.55 wt%, more preferably 0.96 wt% or more and 1.38 wt% or less. .
Next, an example of the relationship between the initial concentration of camphor and the collapse rate of the pattern P1 when the solvent is acetone will be described with reference to FIGS. 15 and 18. FIG.

As shown in measurement conditions 3-3 of FIG. 15, when the initial concentration of camphor was 0.62 wt %, the collapse rate of pattern P1 was 86.6%.
As shown in measurement conditions 3-4 in FIG. 15, the collapse rate of pattern P1 was 60.2% when the initial concentration of camphor was 0.69 wt %.
As shown in measurement conditions 3-9 in FIG. 15, when the initial concentration of camphor was 1.04 wt %, the collapse rate of pattern P1 was 99.7%.

As shown in measurement conditions 3-8 in FIG. 15, the collapse rate of pattern P1 was 82.2% when the initial concentration of camphor was 0.96 wt %.
As shown in measurement conditions 3-7 in FIG. 15, when the initial concentration of camphor was 0.89 wt %, the collapse rate of pattern P1 was 76.4%.
As can be seen from FIGS. 15 and 18, when the initial concentration of camphor increases from 0.62 wt % to 0.69 wt %, the collapse rate of pattern P1 decreases sharply (measurement condition 3-3 → measurement Conditions 3-4). When the initial concentration of camphor decreased from 1.04 wt % to 0.96 wt %, the collapse rate of pattern P1 also decreased sharply (measurement condition 3-9→measurement condition 3-8).

However, when the initial concentration of camphor is in the range of 0.96 wt % or more and 1.04 wt % or less, the collapse rate of the pattern P1 is not so low. When the initial concentration of camphor decreased from 0.96 wt% to 0.89 wt% (measurement condition 3-8 → measurement condition 3-7), the collapse rate of pattern P1 decreased sharply, and pattern P1 relatively low collapse rate. Therefore, when the solvent is acetone, the initial concentration of camphor is preferably greater than 0.62 wt% and less than or equal to 0.96 wt%.

Next, with reference to FIGS. 16 and 19, an example of the relationship between the initial concentration of camphor and the collapse rate of the pattern P1 when the solvent is PGEE will be described.
As shown in measurement condition 4-3 of FIG. 16, the collapse rate of pattern P1 was 98.9% when the initial concentration of camphor was 3.06 wt %.
As shown in measurement conditions 4-4 in FIG. 16, when the initial concentration of camphor was 3.55 wt %, the collapse rate of pattern P1 was 88.3%.

As shown in measurement conditions 4-5 in FIG. 16, when the initial concentration of camphor was 4.23 wt %, the collapse rate of pattern P1 was 79.4%.
As shown in measurement conditions 4-8 in FIG. 16, the collapse rate of pattern P1 was 99.5% when the initial concentration of camphor was 9.95 wt %.
As shown in measurement conditions 4-7 in FIG. 16, when the initial concentration of camphor was 6.86 wt %, the collapse rate of pattern P1 was 62.1%.

As shown in measurement conditions 4-6 in FIG. 16, when the initial concentration of camphor was 5.23 wt %, the collapse rate of pattern P1 was 57.5%.
As can be seen from FIGS. 15 and 18, when the initial concentration of camphor increases from 3.06 wt % to 3.55 wt % (measurement condition 4-3→measurement condition 4-4), the collapse rate of pattern P1 sharply increases. However, the collapse rate of the pattern P1 is not very low in this range. When the initial concentration of camphor increased from 3.55 wt% to 4.23 wt% (measurement condition 4-4 → measurement condition 4-5), the collapse rate of pattern P1 decreased sharply, and pattern P1 collapsed. relatively low rate.

In addition, when the initial concentration of camphor decreased from 9.95 wt% to 6.86 wt% (measurement condition 4-8 → measurement condition 4-7), the collapse rate of pattern P1 decreased sharply, but in this range , the case where the collapse rate of the pattern P1 is not so low. That is, when the initial concentration of camphor is around 6.86 wt %, the collapse rate of the pattern P1 is low, but when the initial concentration of camphor is around 9.95 wt %, the collapse rate of the pattern P1 is high.

When the initial concentration of camphor decreased from 6.86 wt % to 5.23 wt % (measurement condition 4-7→measurement condition 4-6), the collapse rate of pattern P1 gradually decreased. Therefore, when the solvent is PGEE, the initial concentration of camphor is preferably greater than 3.55 wt% and less than or equal to 6.86 wt%.
FIG. 20 is a graph in which the polygonal lines in FIGS. 17 to 19 are superimposed. 20, the polygonal line (IPA) in FIG. 17 is indicated by a solid line, the polygonal line (acetone) in FIG. 18 is indicated by a broken line, and the polygonal line (PGEE) in FIG. 19 is indicated by a dashed line.

When the solvent was IPA, pattern P1 had the lowest collapse rate of 37.3% when the initial concentration of camphor was 1.13 wt % (measurement condition 2-3).
When the solvent was acetone, pattern P1 had the lowest collapse rate of 57.6% when the initial concentration of camphor was 0.78 wt % (measurement condition 3-5).
When the solvent was PGEE, pattern P1 had the lowest collapse rate of 57.5% when the initial concentration of camphor was 5.23 wt % (measurement conditions 4-6).

In other words, the initial concentration of camphor at the lowest collapse rate for pattern P1 is 0.78 wt% when the solvent is acetone, 1.13 wt% when the solvent is IPA, and PGEE as the solvent. was 5.23 wt%. Focusing on these solvents and comparing them, the initial concentration of camphor when the collapse rate of pattern P1 is the lowest increases as the vapor pressure of the solvent decreases. That is, if the solvent evaporates easily, the concentration of the sublimable substance contained in the pre-drying treatment liquid does not necessarily have to be high. Conversely, if the solvent is difficult to evaporate, it is necessary to increase the concentration of the sublimable substance contained in the pre-drying treatment liquid.

In the present invention, it is necessary to form the solidified body 101 containing the sublimable substance on the surface of the substrate W by evaporating the solvent from the pre-drying treatment liquid. You may perform the process to carry out.
As described above, according to the measurement results of FIG. 9, when the initial concentration of camphor is set to a value within the preferred range, the embedding rate is automatically set to a value within the preferred range. Therefore, in the measurements of FIGS. 14 to 16 as well, if the initial concentration of camphor is set to a value within the preferred range, the embedding rate is also automatically set to a value within the preferred range. It is believed that this reduced the collapse rate of the pattern P1.

However, depending on the shape and strength of the pattern P1, even if the initial concentration of camphor is set to a value within the preferred range, the embedding rate is not necessarily set to a value within the preferred range. Similarly, depending on the shape and intensity of the pattern P1, even if the embedding rate is set to a value within the preferred range, it is not necessarily the case that the initial concentration of camphor is set to a value within the preferred range. .

As described above, in the first embodiment, the pre-drying treatment liquid containing the sublimable substance corresponding to the solute and the solvent is supplied to the surface of the substrate W on which the pattern P1 is formed. After that, the solvent is evaporated from the drying pretreatment liquid. As a result, a solidified body 101 containing a sublimable substance is formed on the surface of the substrate W. As shown in FIG. Thereafter, the solidified body 101 on the substrate W is changed into gas without passing through liquid. Thereby, the solidified body 101 is removed from the surface of the substrate W. FIG. Therefore, compared with conventional drying methods such as spin drying, the collapse rate of the pattern P1 can be reduced.

A solid 101 containing a sublimable substance is formed on the surface of the substrate W by evaporating the solvent from the pre-drying treatment liquid. The embedding ratio is greater than 76 and less than 219 when the solid 101 is formed. As described above, when the embedding rate is outside this range, the number of collapses of the pattern P1 increases depending on the strength of the pattern P1. Conversely, if the embedding rate is within this range, even if the strength of the pattern P1 is low, the number of collapses of the pattern P1 can be reduced. Therefore, even if the strength of the pattern P1 is low, the collapse rate of the pattern P1 can be reduced.

Next, a second embodiment will be described.
The main difference of the second embodiment with respect to the first embodiment is that the pre-drying treatment liquid contains an adsorptive substance in addition to the sublimable substance and the solvent.
21 to 23F, the same reference numerals as those in FIG. 1 etc. are attached to the same configurations as those shown in FIGS. 1 to 20, and the description thereof will be omitted.

FIG. 21 is a schematic horizontal view of the inside of the processing unit 2 provided in the substrate processing apparatus 1 according to the second embodiment.
The plurality of nozzles of the processing unit 2 further includes a second chemical liquid nozzle 31B that ejects toward the upper surface of the substrate W a chemical liquid that is different in type from the chemical liquid that is ejected from the chemical liquid nozzle 31 corresponding to the first chemical liquid nozzle. . The second chemical liquid nozzle 31B may be a horizontally movable scan nozzle within the chamber 4 or may be a fixed nozzle fixed to the partition wall 5 of the chamber 4 . FIG. 21 shows an example in which the second chemical liquid nozzle 31B is a scan nozzle.

The second chemical liquid nozzle 31B is connected to a second chemical liquid pipe 32B that guides the chemical liquid to the second chemical liquid nozzle 31B. When the second chemical liquid valve 33B interposed in the second chemical liquid pipe 32B is opened, the chemical liquid is continuously discharged downward from the outlet of the second chemical liquid nozzle 31B. As long as the chemical liquid is different in type from the chemical liquid discharged from the chemical liquid nozzle 31, the chemical liquid discharged from the second chemical liquid nozzle 31B may be sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid, aqueous ammonia, or aqueous hydrogen peroxide. , an organic acid (eg, citric acid, oxalic acid, etc.), an organic alkali (eg, TMAH: tetramethylammonium hydroxide, etc.), a surfactant, and a corrosion inhibitor. Other liquids may be used.

The second chemical liquid nozzle 31B is connected to a nozzle moving unit 34B that moves the second chemical liquid nozzle 31B in at least one of the vertical direction and the horizontal direction. The nozzle moving unit 34B has a processing position where the chemical liquid discharged from the second chemical liquid nozzle 31B is supplied to the upper surface of the substrate W, a standby position where the second chemical liquid nozzle 31B is positioned around the processing cup 21 in plan view, , the second chemical liquid nozzle 31B is moved horizontally.

As described above, the pre-drying treatment liquid contains an adsorptive substance in addition to the sublimable substance and solvent. The pre-drying treatment liquid is a solution containing a sublimable substance corresponding to a solute, a solvent that dissolves with the sublimable substance, and an adsorbent that adsorbs to the surface of the pattern P1 (see FIG. 23A). Sublimable substances, solvents, and adsorbents are substances of different types. The adsorptive substance is a substance that dissolves with at least one of the sublimable substance and the solvent.

A solvent is a dissolved substance liquid that dissolves with the sublimable substance. The concentration of the dissolved substance in the pre-drying treatment liquid is higher than the concentration of the sublimable substance in the pre-drying treatment liquid, and higher than the concentration of the adsorbed substance in the pre-drying treatment liquid. The concentration of the adsorptive substance in the pre-drying treatment liquid may be the same as the concentration of the sublimable substance in the pre-drying treatment liquid, or may be different from the concentration of the sublimable substance in the pre-drying treatment liquid.

Adsorbents are amphipathic molecules containing both hydrophilic and hydrophobic groups. The adsorbent may be a surfactant. If the sublimable substance and the solvent are different in type, the adsorbent may be a substance that changes from a solid to a gas at normal temperature or normal pressure without going through a liquid state (sublimable substance). It may be a different substance. A sublimable substance may be a hydrophobic substance, a hydrophilic substance, or an amphipathic molecule. Likewise, the solvent may be a hydrophobic or hydrophilic substance, or an amphiphilic molecule.

If the sublimable substance is a hydrophilic substance or an amphipathic molecule, the adsorptive substance may be more hydrophilic than the sublimable substance. In other words, the solubility of the adsorbent material in water may be higher than the solubility of the sublimable material in water. When the sublimable substance is a hydrophobic substance or an amphipathic molecule, the sublimable substance may be more hydrophobic than the adsorbent substance. In other words, the solubility of the sublimable material in oil may be higher than the solubility of the adsorbent material in oil. These also apply to solvents.

When the surface of the pattern P1 is hydrophilic and the adsorbing substance is more hydrophilic than the sublimating substance, the adsorbing substance is more likely to be adsorbed to the surface of the pattern P1 than the sublimating substance. The hydrophilic group of the adsorbent adheres to the surface of the pattern P1, and the sublimable substance adheres to the hydrophobic group of the adsorbent adhered to the surface of the pattern P1. When the surface of the pattern P1 is hydrophobic and the sublimation substance is more hydrophobic than the adsorption substance, the sublimation substance is more easily adsorbed to the surface of the pattern P1 than the adsorption substance. Therefore, regardless of whether the surface of pattern P1 is hydrophilic or hydrophobic, the sublimable substance can be positioned on or near the surface of pattern P1.

The freezing point of sublimable substances is above room temperature. The freezing point of the sublimable substance may be higher than the boiling point of the solvent. The freezing point of the solvent is below room temperature. The freezing point of the adsorbent may be room temperature or may be different from room temperature. When the freezing point of the adsorbent is higher than room temperature, the freezing point of the adsorbent may be equal to or different from the freezing point of the sublimable material. The freezing point of the pre-drying treatment liquid is lower than room temperature (23° C. or a value in the vicinity thereof). The freezing point of the pre-drying treatment liquid may be room temperature or higher.

The vapor pressure of the solvent is higher than the vapor pressure of the sublimable substance and higher than the vapor pressure of the adsorbent. The vapor pressure of the adsorbent may be equal to the vapor pressure of the sublimable material or may be different from the vapor pressure of the sublimable material. The solvent evaporates from the drying pretreatment liquid at an evaporation rate higher than that of the sublimable substance and the adsorbent substance. The freezing point of the drying pretreatment liquid decreases as the solvent evaporates. When the freezing point of the pre-drying treatment liquid drops to room temperature, the pre-drying treatment liquid changes from liquid to solid. Thereby, a solidified body 101 containing a sublimable substance is formed.

An example in which the sublimable substance is camphor, the solvent is IPA, and the adsorbent is tertiary butyl alcohol will be described below. In the following description, the dry pretreatment liquid is a solution of camphor, IPA, and tertiary butyl alcohol. Instead of camphor, naphthalene may be included in the dry pretreatment liquid. Instead of IPA, acetone or PGEE may be included in the dry pretreatment liquid. Cyclohexanol may be contained in the dry pretreatment liquid instead of tertiary butyl alcohol.

The molecule of camphor contains a hydrocarbon group, which is a hydrophobic group, and a carbonyl group, which is a hydrophilic group. The molecule of IPA contains an alkyl group, which is a hydrophobic group, and a hydroxyl group, which is a hydrophilic group. A molecule of tertiary butyl alcohol also contains an alkyl group, which is a hydrophobic group, and a hydroxyl group, which is a hydrophilic group. IPA and tertiary butyl alcohol are amphipathic molecules. Camphor, although technically an amphipathic molecule, is considered a hydrophobic substance due to its much lower water solubility compared to tertiary butyl alcohol. Camphor is more hydrophobic than tertiary butyl alcohol.

The first tank 87A and the second tank 87B shown in FIG. 3 store pre-drying liquids having the same adsorption substance concentration and different sublimation substance concentrations. Therefore, even if the pre-drying treatment liquid supplied from the first tank 87A is mixed with the pre-drying treatment liquid supplied from the second tank 87B, the concentration of the adsorbent in the mixed pre-drying treatment liquid is 87A and the concentration of the adsorbent in the pre-drying liquid in the second tank 87B. The initial concentration of the sublimable substance in the pretreatment liquid for drying in the first tank 87A and the second tank 87B may be set to the same value as in the first embodiment, or may be set to a different value from the first embodiment. may be set.

Next, an example of processing of the substrate W according to the second embodiment will be described.
FIG. 22 is a process chart for explaining an example of processing of the substrate W according to the second embodiment. In the following, reference is made to FIGS. 21 and 22. FIG.
In an example of the processing of the substrate W according to the second embodiment, steps S3-1 to S4-2 shown in FIG. 22 are performed instead of steps S3 to S4 shown in FIG. Steps other than these are the same as steps S1 to S2 and steps S5 to S11 shown in FIG. Therefore, steps S3-1 to S4-2 will be described below.

An example in which hydrofluoric acid and SC1 (a mixture of ammonia, hydrogen peroxide, and water) are sequentially supplied to a silicon wafer corresponding to the substrate W will be described below. A natural oxide film formed on a silicon wafer is removed from the silicon wafer by supplying hydrofluoric acid. Thereby, silicon is exposed on the surface of the pattern P1. SC1 is then applied to the silicon wafer. The silicon exposed on the surface of the pattern P1 changes to silicon oxide upon contact with SC1. This changes the surface of the pattern P1 from hydrophobic to hydrophilic. Therefore, the pre-drying treatment liquid is supplied to the silicon wafer when the surface of the pattern P1 is hydrophilic.

As shown in FIG. 22, after the substrate W starts rotating (step S2 in FIG. 22), hydrofluoric acid, which is an example of a chemical solution, is supplied to the upper surface of the substrate W to cover the entire upper surface of the substrate W. 22) is performed to form a liquid film.
Specifically, the nozzle moving unit 34 moves the chemical liquid nozzle 31 from the standby position to the processing position in a state where the blocking member 51 is positioned at the upper position and at least one guard 24 is positioned at the upper position. . After that, the chemical valve 33 is opened, and the chemical nozzle 31 starts discharging hydrofluoric acid. After a predetermined period of time has passed since the chemical valve 33 was opened, the chemical valve 33 is closed and the discharge of hydrofluoric acid is stopped. After that, the nozzle moving unit 34 moves the liquid medicine nozzle 31 to the standby position.

The hydrofluoric acid discharged from the chemical liquid nozzle 31 collides with the upper surface of the substrate W rotating at the liquid supply speed, and then flows outward along the upper surface of the substrate W due to centrifugal force. Therefore, hydrofluoric acid is supplied to the entire upper surface of the substrate W, and a liquid film of hydrofluoric acid covering the entire upper surface of the substrate W is formed. When the chemical nozzle 31 is discharging hydrofluoric acid, the nozzle moving unit 34 may move the position where the hydrofluoric acid lands on the upper surface of the substrate W so that it passes through the central portion and the outer peripheral portion. However, the liquid landing position may be stationary at the central portion.

Next, a first rinse solution supply step (step S4-1 in FIG. 22) is performed in which pure water, which is an example of a rinse solution, is supplied to the upper surface of the substrate W to wash away the hydrofluoric acid on the substrate W. FIG.
Specifically, the nozzle moving unit 38 moves the rinse liquid nozzle 35 from the standby position to the processing position in a state where the blocking member 51 is positioned at the upper position and at least one guard 24 is positioned at the upper position. Let After that, the rinse liquid valve 37 is opened, and the rinse liquid nozzle 35 starts discharging the rinse liquid. The guard elevating unit 27 may vertically move at least one guard 24 to switch the guard 24 that receives the liquid discharged from the substrate W before the pure water discharge is started. After a predetermined period of time has passed since the rinse liquid valve 37 was opened, the rinse liquid valve 37 is closed and the discharge of the rinse liquid is stopped. After that, the nozzle moving unit 38 moves the rinse liquid nozzle 35 to the standby position.

The pure water discharged from the rinse liquid nozzle 35 collides with the upper surface of the substrate W rotating at the liquid supply speed, and then flows outward along the upper surface of the substrate W due to centrifugal force. Hydrofluoric acid on the substrate W is replaced with pure water discharged from the rinse liquid nozzle 35 . As a result, a pure water liquid film covering the entire upper surface of the substrate W is formed. When the rinse liquid nozzle 35 is discharging pure water, the nozzle moving unit 38 moves the pure water landing position on the upper surface of the substrate W so that the pure water landing position passes through the central portion and the outer peripheral portion. Alternatively, the liquid landing position may be stationary at the central portion.

Next, a second chemical solution supply step (step S3-2 in FIG. 22) is performed to supply SC1, which is an example of a chemical solution, to the upper surface of the substrate W to form a liquid film of SC1 covering the entire upper surface of the substrate W. FIG.
Specifically, in a state where the blocking member 51 is positioned at the upper position and at least one guard 24 is positioned at the upper position, the nozzle moving unit 34B moves the second chemical liquid nozzle 31B from the waiting position to the processing position. move. After that, the second chemical liquid valve 33B is opened, and the second chemical liquid nozzle 31B starts discharging SC1. When a predetermined time has passed since the second chemical valve 33B was opened, the second chemical valve 33B is closed and the discharge of SC1 is stopped. After that, the nozzle moving unit 34B moves the second chemical liquid nozzle 31B to the standby position.

SC1 discharged from the second chemical liquid nozzle 31B collides with the upper surface of the substrate W rotating at the liquid supply speed, and then flows outward along the upper surface of the substrate W due to centrifugal force. The pure water on the substrate W is replaced with SC1 discharged from the second chemical nozzle 31B. As a result, a liquid film of SC1 covering the entire upper surface of the substrate W is formed. When the second chemical liquid nozzle 31B is discharging SC1, the nozzle moving unit 34B may move the liquid landing position of SC1 on the upper surface of the substrate W so that the liquid landing position passes through the central portion and the outer peripheral portion. However, the liquid landing position may be stationary at the central portion.

Next, a second rinse solution supply step (step S4-2 in FIG. 22) is performed in which pure water, which is an example of a rinse solution, is supplied to the upper surface of the substrate W to wash away the SC1 on the substrate W. FIG.
Specifically, the nozzle moving unit 38 moves the rinse liquid nozzle 35 from the standby position to the processing position in a state where the blocking member 51 is positioned at the upper position and at least one guard 24 is positioned at the upper position. Let After that, the rinse liquid valve 37 is opened, and the rinse liquid nozzle 35 starts discharging the rinse liquid. The guard elevating unit 27 may vertically move at least one guard 24 to switch the guard 24 that receives the liquid discharged from the substrate W before the pure water discharge is started. After a predetermined period of time has passed since the rinse liquid valve 37 was opened, the rinse liquid valve 37 is closed and the discharge of the rinse liquid is stopped. After that, the nozzle moving unit 38 moves the rinse liquid nozzle 35 to the standby position.

The pure water discharged from the rinse liquid nozzle 35 collides with the upper surface of the substrate W rotating at the liquid supply speed, and then flows outward along the upper surface of the substrate W due to centrifugal force. SC1 on the substrate W is replaced with pure water discharged from the rinsing liquid nozzle 35 . As a result, a pure water liquid film covering the entire upper surface of the substrate W is formed. When the rinse liquid nozzle 35 is discharging pure water, the nozzle moving unit 38 moves the pure water landing position on the upper surface of the substrate W so that the pure water landing position passes through the central portion and the outer peripheral portion. Alternatively, the liquid landing position may be stationary at the central portion.

After the second rinse liquid supplying step (step S4-2 in FIG. 22) is performed, the replacement liquid and the pre-drying treatment liquid are supplied in the same manner as in the example of the substrate W processing according to the first embodiment shown in FIG. The solidified material 101 (see FIG. 23E) on the surface of the substrate W is sublimated (steps S7 to S9 in FIG. 22). After that, the substrate W is unloaded from the chamber 4 (steps S10 to S11 in FIG. 22). Thereby, the processed substrate W is unloaded from the chamber 4 .

Next, a phenomenon assumed to occur on the surface of the pattern P1 to which the pre-drying treatment liquid is supplied will be described.
23A to 23F are cross-sectional views of the substrate W for explaining the same phenomenon. Tertiary butyl alcohol is represented as TBA in FIGS. 23A-23E. In FIGS. 23A to 23C, thick straight lines represent the hydrophilic groups of the tertiary butyl alcohol molecules, and black circles represent the hydrophobic groups of the tertiary butyl alcohol molecules.

As described above, in one example of the processing of the substrate W according to the second embodiment, hydrofluoric acid and SC1 are sequentially supplied to the silicon wafer corresponding to the substrate W. FIG. The surface of the pattern P1 becomes hydrophobic by supplying hydrofluoric acid. After that, the surface of the pattern P1 becomes hydrophilic due to the supply of SC1. Therefore, a dry pretreatment liquid containing camphor, IPA, and tertiary butyl alcohol is supplied to the silicon wafer when the surface of the pattern P1 is hydrophilic.

Camphor is a substance that can be considered hydrophobic, and tert-butyl alcohol is an amphipathic molecule containing hydrophilic and hydrophobic groups. As shown in FIG. 23A, since the surface of the pattern P1 is hydrophilic, the hydrophilic groups of the tertiary-butyl alcohol molecules are attracted to the surface of the pattern P1. Thereby, as shown in FIG. 23B, the hydrophilic groups of the tertiary butyl alcohol molecules are adsorbed to the surface of the pattern P1, and a thin film of tertiary butyl alcohol is formed on the side surface Ps and the upper surface Pu of the pattern P1.

FIG. 23B shows an example in which a monomolecular film of tertiary butyl alcohol is formed along the surface of the pattern P1. As shown in FIG. 23C, in this example, the hydrophobic groups of the camphor molecules are attached to the hydrophobic groups of the tertiary butyl alcohol molecules adsorbed on the surface of the pattern P1. When the laminated film of tertiary butyl alcohol is formed along the surface of the pattern P1, the hydrophobic group of the camphor molecule is attached to the hydrophobic group of the tertiary butyl alcohol molecule exposed on the surface layer of the laminated film. As a result, camphor is held on the surface of the pattern P1 through the thin film of tertiary butyl alcohol.

As shown in FIG. 23C, the camphor molecules in the dry pretreatment liquid adhere to the camphor molecules retained on the thin film of tertiary butyl alcohol. Due to this phenomenon, many camphor molecules are held on the side surface Ps of the pattern P1 via the molecular layer of tertiary butyl alcohol. Therefore, a sufficient amount of camphor molecules enter between patterns P1, as shown in FIG. 23D. FIG. 23D shows an example in which a thin film of tertiary butyl alcohol is formed not only on the side surface Ps and upper surface Pu of the pattern P1, but also on the bottom surface Pb of the recess formed between two adjacent patterns P1. there is

IPA corresponding to the solvent is a state in which a thin film of tertiary butyl alcohol is formed along the surface of the pattern P1, and a plurality of camphor molecules are held on the surface of the pattern P1 via the thin film of tertiary butyl alcohol. evaporate from the drying pretreatment liquid at . As the IPA evaporates, the freezing point of the dry pretreatment liquid decreases and the concentrations of camphor and tert-butyl alcohol increase. As a result, a solidified body 101 containing camphor and tertiary butyl alcohol is formed on the surface of the substrate W, as shown in FIG. 23E. Thereafter, the solidified body 101 is vaporized and removed from the surface of the substrate W, as shown in FIG. 23F.

According to the research of the present inventors, when the substrate W according to the second embodiment is processed using a silicon plate-shaped sample on which the pattern P1 is formed, camphor, IPA, and It was confirmed that when the tertiary butyl alcohol solution was used as the pre-drying treatment liquid, the collapse rate of the pattern P1 was lower than when the camphor and IPA solutions were used as the pre-drying treatment liquid. When the concentration of tertiary butyl alcohol (volume percent concentration) was changed in the range of 0.1 vol % to 10 vol %, no significant difference was observed in the collapse rate of pattern P1. Therefore, if tertiary butyl alcohol is added even in a small amount, the collapse rate of the pattern P1 is lowered. The concentration of tertiary butyl alcohol may be a value within the above range, or may be a value outside the above range.

In the second embodiment, the following effects can be obtained in addition to the effects of the first embodiment. Specifically, in the second embodiment, a pre-drying treatment liquid containing an adsorptive substance in addition to a sublimable substance and a solvent is supplied to the surface of the substrate W on which the pattern P1 is formed. After that, the solvent is evaporated from the drying pretreatment liquid. As a result, a solidified body 101 containing a sublimable substance is formed on the surface of the substrate W. As shown in FIG. Thereafter, the solidified body 101 on the substrate W is changed into gas without passing through liquid. Thereby, the solidified body 101 is removed from the surface of the substrate W. FIG. Therefore, compared with conventional drying methods such as spin drying, the collapse rate of the pattern P1 can be reduced.

A sublimable substance is a substance containing a hydrophobic group in its molecule. An adsorbent is a substance containing a hydrophobic group and a hydrophilic group in its molecule. The hydrophilicity of the adsorptive material is higher than that of the sublimable material. Regardless of whether the surface of the pattern P1 is hydrophilic or hydrophobic, or whether the surface of the pattern P1 includes a hydrophilic portion and a hydrophobic portion, the adsorbent in the pre-drying treatment liquid is , adsorbs to the surface of the pattern P1.

Specifically, when the surface of the pattern P1 is hydrophilic, the hydrophilic group of the adsorbent in the pre-drying treatment liquid adheres to the surface of the pattern P1, and the hydrophobic group of the sublimable substance in the pre-drying treatment liquid adheres to the surface of the pattern P1. It adheres to the hydrophobic groups of substances. Thereby, the sublimable substance is held on the surface of the pattern P1 via the adsorbing substance. When the surface of the pattern P1 is hydrophobic, at least the hydrophobic group of the sublimable substance adheres to the surface of the pattern P1. Therefore, regardless of whether the surface of the pattern P1 is hydrophilic or hydrophobic, or even if the surface of the pattern P1 contains both hydrophilic and hydrophobic portions, the sublimation property before evaporation of the solvent. Material is retained on or near the surface of pattern P1.

When the sublimable substance is hydrophilic and the surface of the pattern P1 is hydrophilic, the sublimable substance is attracted to the surface of the pattern P1 by electrical attraction. On the other hand, when the sublimating substance is hydrophobic and the surface of the pattern P1 is hydrophilic, such attractive force is weak or does not occur, so the sublimating substance is less likely to adhere to the surface of the pattern P1. Furthermore, in addition to the fact that the sublimation substance is hydrophobic and the surface of the pattern P1 is hydrophilic, if the space between the patterns P1 is extremely narrow, a sufficient amount of the sublimation substance does not enter between the patterns P1. can be considered. These phenomena also occur when the sublimation substance is hydrophilic and the surface of the pattern P1 is hydrophobic.

If the solvent is evaporated without the sublimable substance on or near the surface of the pattern P1, the solvent in contact with the surface of the pattern P1 may apply a collapsing force to the pattern P1, causing the pattern P1 to collapse. If the solvent is evaporated without a sufficient amount of the sublimable substance between the patterns P1, the gaps between the patterns P1 may not be filled with the solidified material 101 and the patterns P1 may collapse. Placing a sublimable substance on or near the surface of the pattern P1 before evaporating the solvent can reduce such collapse. Thereby, the collapse rate of the pattern P1 can be reduced.

In the second embodiment, not only the sublimable substance but also the adsorptive substance have sublimability. Adsorbents change from solid to gas at normal temperature or pressure without passing through liquid. When at least part of the surface of the pattern P1 is hydrophilic, the solvent evaporates while the adsorbent in the pre-drying treatment liquid is adsorbed on the surface of the pattern P1. The adsorbed substance changes from liquid to solid on the surface of the pattern P1. As a result, a solidified body 101 containing the adsorptive substance and the sublimable substance is formed. After that, the solid of the adsorbent changes to gas without passing through liquid on the surface of the pattern P1. Therefore, the collapsing force can be reduced compared to the case where the liquid is vaporized on the surface of the pattern P1.

In the second embodiment, the surface of the substrate W is supplied with a pre-drying treatment liquid having a low adsorbent concentration. When at least part of the surface of the pattern P1 is hydrophilic, hydrophilic groups of the adsorbent adhere to the surface of the pattern P1, and a monomolecular film of the adsorbent is formed along the surface of the pattern P1. When the concentration of the adsorbent is high, a plurality of monomolecular films are stacked to form a laminated film of the adsorbent along the surface of the pattern P1. In this case, the sublimable substance is held on the surface of the pattern P1 via the layered film of the adsorbing substance. If the layered film of the adsorbing substance is thick, the amount of the sublimating substance entering between the patterns P1 is reduced. Therefore, by lowering the concentration of the adsorbed substance, more sublimable substance can enter between the patterns P1.

In the second embodiment, the surface of the substrate W is supplied with a pre-drying treatment liquid containing a sublimable substance that is more hydrophobic than the adsorbent. Since both the sublimable substance and the adsorptive substance contain hydrophobic groups, both the sublimable substance and the adsorptive substance adhere to the surface of the pattern P1 when at least a part of the surface of the pattern P1 is hydrophobic. obtain. However, since the affinity between the sublimating substance and the pattern P1 is higher than the affinity between the adsorbing substance and the pattern P1, the sublimating substance adheres to the surface of the pattern P1 more than the adsorbing substance. This allows more sublimable substance to adhere to the surface of the pattern P1.

Other Embodiments The present invention is not limited to the contents of the above-described embodiments, and various modifications are possible.
For example, in order to change the thickness T1 of the solidified body 101, conditions other than the concentration of the pre-drying treatment liquid may be changed. For example, in addition to or instead of the concentration of the pre-drying treatment liquid, the temperature of the pre-drying treatment liquid may be changed.

The pattern P1 is not limited to a single-layer structure, and may have a laminated structure. At least part of the pattern P1 may be made of a material other than silicon. For example, at least part of the pattern P1 may be made of metal.
In one example of the processing of the substrate W according to the first and second embodiments, in order to maintain the pre-drying treatment liquid on the substrate W in a liquid state, the temperature is higher than the freezing point of the pre-drying treatment liquid and higher than the boiling point of the pre-drying treatment liquid. A temperature holding step may be performed to maintain the pre-drying treatment liquid on the substrate W at a lower liquid maintenance temperature.

If the rinsing liquid such as pure water on the substrate W can be replaced with the pre-drying treatment liquid, the pre-drying treatment liquid supplying step is performed without performing the replacement liquid supplying step of replacing the rinsing liquid on the substrate W with the replacement liquid. may
In one example of the processing of the substrate W according to the second embodiment, the surface of the pattern P1 may be hydrophilic from the beginning, that is, before it is loaded into the substrate processing apparatus 1 . In this case, the second chemical solution supply step (step S3-2 in FIG. 22) and the second rinse solution supply step (step S4-2 in FIG. 22) may be omitted. Furthermore, the chemical liquid supplied to the substrate W in the first chemical liquid supply step (step S3-1 in FIG. 22) may be a chemical liquid other than hydrofluoric acid.

In one example of the processing of the substrate W according to the second embodiment, when the pre-drying treatment liquid is supplied to the surface of the substrate W, the surface of the pattern P1 may be hydrophobic. In this case, the surface of the pattern P1 may be initially hydrophobic, or may be changed to be hydrophobic while the substrate W is being processed.
In the second embodiment, if the initial concentration of the sublimable substance (concentration of the sublimable substance in the pre-drying treatment liquid before being supplied to the substrate W) is not changed, the first tank 87A and the second tank 87A shown in FIG. One of the tanks 87B may be omitted.

In the second embodiment, the adsorptive substance may be mixed with the solution of the sublimable substance and the solvent outside the first tank 87A and the second tank 87B. In this case, the adsorptive substance may be mixed before the solution of the sublimable substance and the solvent is discharged from the pre-drying treatment liquid nozzle 39 , or the solution of the sublimable substance and the solvent is discharged from the pre-drying treatment liquid nozzle 39 . may be mixed after being mixed. In the latter case, the adsorbent may be mixed with the solution of the sublimable substance and the solvent in the space between the pre-drying treatment liquid nozzle 39 and the substrate W, or may be mixed with the solution of the sublimable substance and the solvent on the upper surface of the substrate W. may be mixed into

The blocking member 51 may include, in addition to the disc portion 52 , a cylindrical portion extending downward from the outer peripheral portion of the disc portion 52 . In this case, when the blocking member 51 is arranged at the lower position, the substrate W held by the spin chuck 10 is surrounded by the cylindrical portion.
The blocking member 51 may rotate around the rotation axis A<b>1 together with the spin chuck 10 . For example, the blocking member 51 may be placed on the spin base 12 so as not to contact the substrate W. FIG. In this case, since the blocking member 51 is connected to the spin base 12 , the blocking member 51 rotates in the same direction and at the same speed as the spin base 12 .

The blocking member 51 may be omitted. However, when supplying a liquid such as pure water to the lower surface of the substrate W, it is preferable that the blocking member 51 is provided. The blocking member 51 can block droplets that have flowed along the outer peripheral surface of the substrate W from the lower surface of the substrate W to the upper surface of the substrate W, and droplets that have rebounded inward from the processing cup 21, so that pre-drying processing on the substrate W can be performed. This is because the liquid mixed in the liquid can be reduced.

The substrate processing apparatus 1 is not limited to an apparatus for processing disk-shaped substrates W, and may be an apparatus for processing polygonal substrates W. FIG.
The substrate processing apparatus 1 is not limited to a single substrate type apparatus, and may be a batch type apparatus that processes a plurality of substrates W collectively.
In addition, various design changes can be made within the scope of the matters described in the claims.

The pre-drying treatment liquid nozzle 39 is an example of a pre-drying treatment liquid supplying means. The center nozzle 55 and the spin motor 14 are examples of solidified body forming means. The center nozzle 55 and spin motor 14 are also an example of sublimation means.

Reference Signs List 1: Substrate processing apparatus 3: Control device 10: Spin chuck 14: Spin motor 39: Pre-drying treatment liquid nozzle 55: Center nozzle 101: Solidified body Hp: Pattern height P1: Pattern T1: Solidified body thickness W: Substrate

Claims (4)

a dry pretreatment liquid supply step of supplying a dry pretreatment liquid, which is a solution containing a sublimable substance that changes to gas without passing through a liquid and a solvent that dissolves with the sublimable substance, to the surface of the substrate on which the pattern is formed;
removing a part of the pre-drying treatment liquid on the surface of the substrate while maintaining the entire surface of the substrate covered with the liquid film of the pre-drying treatment liquid, and removing the pre-drying treatment liquid on the substrate; A film thickness reduction step of reducing the film thickness of
By evaporating the solvent from the pre-drying treatment liquid on the surface of the substrate, the film thickness of the pre-drying treatment liquid is reduced while increasing the concentration of the sublimable substance in the pre-drying treatment liquid. a solidified body forming step of forming a solidified body containing the sublimable substance on the surface of the substrate;
a sublimation step of removing the solidified body from the surface of the substrate by sublimating it,
By adjusting the initial concentration of the sublimable substance in the pre-drying treatment liquid before being supplied to the substrate, the ratio of the thickness of the solidified body at the time of solidification to the height of the pattern multiplied by 100 is 76. and less than 219. further comprising the step of maintaining a state in which the solidified body is in contact with gas for the entire period from when the solidified body is formed on the surface of the substrate until the solidified body is removed from the surface of the substrate. Item 1. The substrate processing method according to item 1. 3. The substrate processing method according to claim 1, wherein the vapor pressure of said solvent is higher than the vapor pressure of said sublimable substance. The adjusting the initial concentration of the sublimable substance includes changing the initial concentration so that the value is greater than 76 and less than 219. Substrate processing method.

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