KR20220157319A - Coating method and coating device - Google Patents

Abstract

A central portion of a lower surface of a substrate is held in a horizontal position by a rotation holding unit. The held substrate rotates around a vertical axis. A coating liquid is supplied to an upper surface of the rotating substrate. In a state in which the substrate rotates, during a liquid supply period before a second time point in a liquid flow period from a first time point at which supply of the coating liquid is finished to the second time point at which fluidity of the coating liquid on the substrate is lost, a volatile rinsing liquid is supplied to at least a part of a lower surface annular portion of the lower surface of the rotating substrate surrounding the central portion of the lower surface.

Description

Coating treatment method and coating treatment device {COATING METHOD AND COATING DEVICE}

The present invention relates to a coating treatment method and a coating treatment apparatus for forming a coating film on a substrate.

A semiconductor substrate, a substrate for FPD (Flat Panel Display) such as a liquid crystal display device or an organic EL (Electro Luminescence) display device, a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, or a solar substrate. In order to perform various treatments on substrates such as battery substrates, a substrate processing apparatus is used.

As an example of a substrate processing device, there is a coating processing device that forms a coating film such as a resist film or an antireflection film on the upper surface of a substrate. In the application processing apparatus, for example, one substrate is held in a horizontal position by a spin chuck. Also, the substrate held by the spin chuck rotates. A coating liquid according to the type of coating film to be formed is supplied to the upper surface of the rotating substrate. The coating liquid supplied onto the substrate is spread over the entire upper surface of the substrate by centrifugal force. A coating film is formed by drying the coating liquid on the substrate.

In the application processing apparatus, the thickness of the coating film formed on the substrate is preferably uniform over the entire substrate. In the process of forming a coating film on a substrate, if there is a large non-uniformity in the temperature distribution of the coating liquid spread on the substrate, it is difficult to make the film thickness distribution uniform. Therefore, a coating treatment method has been proposed in which the temperature of the substrate and the coating liquid on the substrate is adjusted by supplying a liquid for temperature adjustment (temperature control liquid) to the lower surface of the substrate during or after supply of the coating liquid to the upper surface of the substrate ( See, for example, Japanese Patent Laid-Open No. 2000-114152). Japanese Unexamined Patent Publication No. 2000-114152 describes using a solvent such as thinner as a liquid for temperature adjustment.

In recent years, with the high density and high integration of devices, it is required to increase the thickness of a coating film formed on a substrate. In order to form a coating film having a large thickness, a high-viscosity coating liquid is used. Such a high-viscosity coating liquid is less likely to spread on a substrate than a low-viscosity coating liquid. In addition, when forming a coating film having a large thickness, the time required for drying is longer compared to when forming a coating film having a small thickness.

Therefore, in the coating process for forming a coating film having a large thickness using a high-viscosity coating liquid, it is necessary to adjust the temperature of the substrate and the coating liquid on the substrate over a long period of time. However, if the liquid for temperature adjustment is continuously supplied to the lower surface of the substrate over a long period of time, the cost of the coating process increases.

An object of the present invention is to provide a coating method and a coating apparatus capable of uniformizing the film thickness distribution at low cost regardless of the thickness of the coating film.

(1) The coating treatment method according to one aspect of the present invention includes the steps of rotating the substrate to which the central portion of the lower surface of the substrate is adsorbed by the rotating holding unit around a vertical axis while maintaining it in a horizontal position, and rotating the substrate by the rotating holding unit. supplying the coating liquid to the upper surface of the substrate, and in a state in which the substrate held by the rotation holding unit rotates, after the first point in time when the supply of the coating liquid is finished, until the second point in time when the fluidity of the coating liquid on the substrate disappears and supplying a volatile rinsing liquid to at least a part of an annular portion of the lower surface of the lower surface of the substrate rotated by the rotating holding unit during the liquid supply period prior to the second time point during the liquid flow period of .

In the coating treatment method, a coating liquid is supplied to the upper surface of a rotating substrate. The coating liquid supplied to the upper surface of the substrate flows through the upper surface of the substrate due to centrifugal force. During the liquid supply period, the rinsing liquid is supplied to the lower annular portion of the substrate. During the liquid supply period, at least a part of the rinsing liquid supplied to the substrate is vaporized after the liquid supply period until the second time point elapses. In this case, the temperature of the annular portion of the lower surface of the substrate is adjusted with high efficiency by the heat of vaporization generated along with the vaporization of the rinse liquid.

By appropriately adjusting the temperature of the annular portion of the lower surface of the substrate, it is possible to suppress occurrence of local change in the movement state of the coating liquid flowing in the radial direction of the substrate. Thereby, the thickness of the coating film formed on the substrate can be made uniform. Therefore, it is not necessary to continuously supply the liquid for temperature adjustment to the substrate during the liquid flow period in order to uniformize the thickness of the coating film. As a result, it becomes possible to uniformize the film thickness distribution at low cost regardless of the thickness of the coating film.

(2) The second point in time may be a point in time when interference fringes generated on the surface of the coating liquid supplied to the upper surface of the substrate disappear after the lapse of the first point in time. In this case, the liquid supply period can be easily and appropriately set by confirming the generation and disappearance of the interference fringes in advance.

(3) The length of the liquid supply period may be 10 seconds or less. Thereby, consumption of the rinse liquid can be further reduced. In addition, the temperature of the substrate can be more appropriately adjusted.

(4) The rotating step includes rotating the substrate so that the coating liquid supplied to the upper surface of the substrate covers the entire upper surface of the substrate at a third time point before the second time point after the first time point has elapsed, and the liquid supply The start time of the period may be determined within the time from the third time point until 5 seconds pass. In this way, the temperature of the substrate can be more appropriately adjusted.

(5) The lower annular portion may be located between the lower surface periphery of the annular lower surface including the outer circumferential end of the substrate and the lower surface central portion of the lower surface of the substrate rotated by the rotation holding unit. Thereby, the temperature of the part located around the central part of the lower surface of the substrate can be more appropriately adjusted.

(6) A coating treatment apparatus according to another aspect of the present invention includes a rotation holding unit that rotates around a vertical axis while holding the substrate in a horizontal position by adsorbing the center portion of the lower surface of the substrate, and the upper surface of the substrate rotated by the rotation holding unit. A coating liquid supply unit for supplying a coating liquid, a rinse liquid supply unit for supplying a volatile rinse liquid to at least a part of the annular portion of the lower surface surrounding the center of the lower surface of the lower surface of the substrate rotated by the rotation holding unit, and holding by the rotation holding unit In a state where the substrate is rotated, the coating liquid is supplied to the upper surface of the substrate, and the liquid flow period from the first point in time when the supply of the coating liquid is finished to the second point in time when the fluidity of the coating liquid on the substrate is lost is second during the liquid flow period. A control unit for controlling the rotation holding unit, the coating liquid supply unit, and the rinse liquid supply unit so that the rinse liquid is supplied to the annular lower surface of the substrate during the liquid supply period prior to the starting point.

In the application processing device, the coating liquid is supplied to the upper surface of the rotating substrate. The coating liquid supplied to the upper surface of the substrate flows through the upper surface of the substrate due to centrifugal force. Then, during the liquid supply period, the rinse liquid is supplied to the annular portion of the lower surface of the substrate. During the liquid supply period, at least a part of the rinsing liquid supplied to the substrate is vaporized after the liquid supply period until the second time point elapses. In this case, the temperature of the annular portion of the lower surface of the substrate is adjusted with high efficiency by the heat of vaporization generated along with the vaporization of the rinse liquid.

By appropriately adjusting the temperature of the annular portion of the lower surface of the substrate, it is possible to suppress occurrence of local change in the movement state of the coating liquid flowing in the radial direction of the substrate. Thereby, the thickness of the coating film formed on the substrate can be made uniform. Therefore, it is not necessary to continuously supply the liquid for temperature adjustment to the substrate during the liquid flow period in order to uniformize the thickness of the coating film. As a result, it becomes possible to uniformize the film thickness distribution at low cost regardless of the thickness of the coating film.

(7) The second point in time may be a point in time when interference fringes generated on the surface of the coating liquid supplied to the upper surface of the substrate disappear after the lapse of the first point in time. In this case, the liquid supply period can be easily and appropriately set by confirming the generation and disappearance of the interference fringes in advance.

(8) The length of the liquid supply period may be 10 seconds or less. Thereby, consumption of the rinse liquid can be further reduced. In addition, the temperature of the substrate can be more appropriately adjusted.

(9) The control unit controls the rotation holding unit so that the coating liquid supplied to the upper surface of the substrate covers the entire upper surface of the substrate at a third time point before the second time point after the first point in time, and at the start of the liquid supply period. may be determined within the time from the third point in time to the elapse of 5 seconds. In this way, the temperature of the substrate can be more appropriately adjusted.

(10) The lower annular portion may be located between the periphery of the annular lower surface including the outer circumferential end of the lower surface of the substrate rotated by the rotation holding unit and the lower surface central portion. Thereby, the temperature of the part located around the central part of the lower surface of the substrate can be more appropriately adjusted.

1 is a schematic cross-sectional view of a coating treatment device according to an embodiment of the present invention.
FIG. 2 is a schematic plan view of the application processing apparatus of FIG. 1 .
Fig. 3 is a plan view showing an example of a resist film in which non-uniformity has occurred in the film thickness distribution.
FIG. 4 is a cross-sectional view for explaining a mechanism estimated for occurrence of unevenness in film thickness distribution in FIG. 3 .
5 is a diagram for explaining a specific example of an application process according to an embodiment of the present invention.
Fig. 6 is a diagram showing the film thickness distribution of the resist films of the three substrates subjected to the coating process for confirming the preferred rinsing starting point.
Fig. 7 is a diagram showing the film thickness distribution of the resist films of the six substrates on which the coating process for confirming the desired length of the liquid supply period has been performed.
Fig. 8 is a diagram showing the uniformity of the film thickness distribution of the resist films of the six substrates on which the coating process was performed in order to confirm the desired length of the liquid supply period.
Fig. 9 is a diagram showing the film thickness distribution of resist films of eight substrates subjected to a coating process for confirming whether it is possible to adjust the film thickness of resist films by supplying a rinse liquid to the outer annular portion of the substrates.
10 is a schematic cross-sectional view showing an example of a configuration of a coating treatment device according to another embodiment.
Fig. 11 is a schematic cross-sectional view showing another configuration example of a coating device according to another embodiment.

Hereinafter, a coating treatment method and a coating treatment apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the substrate refers to a substrate for a flat panel display (FPD) used for a liquid crystal display device or an organic EL (electro luminescence) display device, a semiconductor substrate, a substrate for an optical disk, a substrate for a magnetic disk, and a substrate for a magneto-optical disk. , a substrate for a photomask, a ceramic substrate, or a substrate for a solar cell. In this embodiment, the upper surface of the substrate is the circuit formation surface (surface), and the lower surface of the substrate is the surface (back surface) opposite to the circuit formation surface. Further, in the present embodiment, the substrate has a circular shape except for the formation portion of the notch in plan view.

[1] Overall configuration of the coating treatment device

FIG. 1 is a schematic cross-sectional view of an application processing device according to an embodiment of the present invention, and FIG. 2 is a schematic plan view of the application processing device 1 of FIG. 1 . In FIG. 2 , illustration of some components among a plurality of components of the coating apparatus 1 of FIG. 1 is omitted. In Fig. 2, the substrate W of Fig. 1 is indicated by a dotted chain line.

As shown in FIG. 1 , the coating device 1 according to the present embodiment mainly includes a rotation holding device 10, a liquid supply device 20, and a control unit 30. The rotating holding device 10 is configured to be capable of rotating the lower surface of the substrate W while adsorbing and holding the center portion thereof.

The liquid supply device 20 includes a resist nozzle 21 and a coating liquid supply system 22 . The coating liquid supply system 22 supplies a resist liquid as a coating liquid to the resist nozzle 21 . The resist nozzle 21 is provided so as to be movable between a position on the side of the substrate W held by the holding device 10 and a position above the substrate W. The resist nozzle 21, while being adsorbed and held by the holding device 10 and positioned above the rotating substrate W, supplies the resist liquid supplied from the coating liquid supply system 22 to the substrate W. Discharge on the upper surface of The control unit 30 includes a CPU (central processing unit) and a memory or a microcomputer, and controls operations of the rotation holding device 10 and the liquid supply device 20 .

The specific structure of the rotation holding device 10 is demonstrated. The rotating holding device 10 includes a suction holding unit 11, a rotating shaft 12, a rotation drive unit 13, a suction unit 14, a cup 15, a drainage guide tube 16, and a plurality of lower surface nozzles 17. ) and a rinse liquid supply system 18.

The adsorption holding portion 11 has a circular upper surface 11u for adsorbing and holding the central portion of the lower surface of the substrate W, and is attached to the upper end of the rotating shaft 12 extending in the vertical direction. A large number of suction holes h (FIG. 2) are formed in the upper surface 11u of the suction holder 11. The rotary drive unit 13 rotates the rotary shaft 12 around its shaft center.

As shown by the thick dotted line in FIG. 1 , an intake path vp is formed inside the suction holding unit 11 and the rotating shaft 12 . The intake path vp is connected to the suction device 14 . The suction device 14 includes, for example, a suction mechanism such as an aspirator, and through an intake passage vp and a plurality of suction holes h, the space on the upper surface 11u of the suction holding part 11 The atmosphere is sucked in and discharged to the outside of the coating treatment device 1 .

As shown in FIG. 2 , the cup 15 is installed so as to surround the suction holder 11 in plan view, and can be moved to a plurality of positions in the vertical direction by a lifting mechanism (not shown). It consists of As shown in FIG. 1 , the cup 15 includes a bottom portion 15x and an outer peripheral wall portion 15y. The bottom portion 15x has a substantially annular shape. The inner peripheral end of the bottom portion 15x is bent upward by a predetermined height. The outer circumferential wall portion 15y extends upward by a predetermined height from the outer circumferential end of the bottom portion 15x, is bent, and is formed so as to extend obliquely upward toward the suction holding portion 11.

A drain 15d is formed on the bottom 15x of the cup 15 . A drainage guide pipe 16 is attached to the portion where the drain 15d is formed in the bottom portion 15x. The lower end of the drainage guide tube 16 is connected to a drainage system (not shown).

As shown in FIG. 2 , a plurality of lower surface nozzles 17 are provided between the inner circumferential end of the outer circumferential wall portion 15y of the cup 15 and the outer circumferential end of the suction holder 11 in plan view. In this example, four lower surface nozzles 17 are provided. A plurality of lower surface nozzles 17 are arranged at equal angular intervals with the center of the suction holder 11 as a standard so as to surround the suction holder 11 in plan view. At the upper end of each lower surface nozzle 17, a liquid discharge port 17b facing upward is provided.

As shown in FIG. 1 , the liquid discharge port 17b of each lower surface nozzle 17 is positioned near the outer circumferential end of the suction holder 11, and the substrate W adsorbed and held by the suction holder 11 opposes the lower side of More specifically, each lower surface nozzle 17 is provided at a position separated from the outer peripheral end of the suction holder 11 by about 5 mm to 80 mm in the radial direction of the suction holder 11 in a plan view. In addition, the coating processing device 1 has a configuration in which the rotation holding device 10 and the liquid supply device 20 are housed in a housing (not shown). The lower surface nozzle 17 is fixed to the housing of the coating apparatus 1, for example. The lower surface nozzle 17 discharges the rinse liquid supplied from the rinse liquid supply system 18 to the lower surface of the substrate W from the liquid discharge port 17b. In this embodiment, as the rinsing liquid, a volatile solvent (such as thinner) capable of dissolving a resist film described later is used.

An overview of the operation of the application processing device 1 having the above configuration will be described. When the application process of the substrate W is started, first, the substrate W is held in a horizontal posture by the suction holding unit 11 . Also, the substrate W is rotated. At this time, the temperature of the adsorption holding part 11 and the substrate W is room temperature (for example, 23 degreeC).

Further, in the horizontal direction, the cup 15 is positioned in the vertical direction so that the inner circumferential surface of the outer circumferential wall portion 15y opposes the outer circumferential end of the substrate W. In this state, the resist nozzle 21 is moved upward of the substrate W by a nozzle moving device (not shown). In addition, a predetermined amount of resist liquid is discharged from the resist nozzle 21 onto the upper surface of the substrate W. As a result, the resist liquid is applied to the upper surface of the rotating substrate W. At this time, the temperature of the resist liquid supplied from the resist nozzle 21 to the substrate W is room temperature (for example, 23°C). In addition, the viscosity of the resist liquid applied on the substrate W is 1 cP or more and 20000 cP or less at room temperature (for example, 23°C).

The resist liquid splashing outward from the rotating substrate W is received by the inner circumferential surface of the outer circumferential wall portion 15y of the cup 15 . The received resist liquid is collected in the bottom 15x of the cup 15, and is led from the drain 15d through the drainage guide tube 16 to a drainage system (not shown). As described above, the process of applying the resist liquid to the entire upper surface of the substrate W during the coating process of the substrate W, that is, the process of forming a liquid film of the resist liquid on the entire upper surface of the substrate W is called a liquid film forming process. .

Next, in a state where the discharge of the resist liquid from the resist nozzle 21 to the substrate W is stopped, rotation of the substrate W continues, so that excess resist among the resist liquid applied to the upper surface of the substrate W The liquid is drained. Further, the liquid film of the resist liquid remaining on the substrate W is dried. As a result, a resist film is formed on the upper surface of the substrate W. In this embodiment, the thickness of the resist film formed on the substrate W is 20 nm or more and 20000 nm or less. As described above, the process of drying the liquid film of the resist liquid applied to the upper surface of the substrate W during the coating process of the substrate W is called a liquid film drying process. In the liquid film drying process, a rinse liquid is discharged from a plurality of lower surface nozzles 17 to the lower surface of the substrate W during a specific period. The reason for this will be described later.

After the resist film is formed on the upper surface of the substrate W, in order to remove the resist liquid or the resist film adhering to the lower surface of the substrate W, a rinse liquid is discharged from a plurality of lower surface nozzles 17 toward the lower surface of the substrate W do. The temperature of the rinsing liquid supplied to the substrate W from each lower surface nozzle 17 is equal to or higher than the temperature of the suction holder 11 (room temperature in this example).

After that, the discharge of the rinsing liquid from the nozzles 17 on each lower surface to the substrate W is stopped. In this state, rotation of the substrate W continues, so that the rinsing liquid applied to the lower surface of the substrate W is dried. As a result, the resist liquid or resist solids adhering to the lower surface of the substrate W are removed. The substrate W on which the resist film is formed by the above series of operations of the coating apparatus 1 is taken out of the coating apparatus 1 and subjected to exposure treatment by an exposure apparatus not shown.

[2] Non-uniformity in the film thickness distribution of the resist film that occurs during the coating process

In the liquid film drying step during the coating process, non-uniformity occurs in the drying state of the resist liquid on the substrate W due to the temperature distribution of the substrate W and the strength of airflow generated in the space surrounding the substrate W. As a result, non-uniformity occurs in the film thickness distribution of the resist film formed on the substrate W. Fig. 3 is a plan view showing an example of a resist film in which non-uniformity has occurred in the film thickness distribution. In FIG. 3 , the outer edge of a portion of the substrate W adsorbed and held by the adsorption holding portion 11 (hereinafter referred to as a contact portion) is indicated by a thick dotted line. In the plan view of FIG. 3 , the resist film R2 formed on the substrate W is represented by a dot pattern having a density corresponding to the thickness of the resist film R2. A portion with a high concentration of the dot pattern indicates a large thickness of the resist film R2, and a portion with a low concentration of the dot pattern indicates a small thickness of the resist film R2.

FIG. 4 is a cross-sectional view for explaining a mechanism estimated for occurrence of unevenness in film thickness distribution in FIG. 3 . In Fig. 4, two cross-sectional views are shown above and below. In these cross-sectional views, similar to the example of the resist film R2 in FIG. 3 , the liquid film of the resist liquid R1 formed on the substrate W and the resist film R2 form a dot pattern with a density corresponding to their thickness. is represented by

The application processing device 1 is basically housed in a clean room. In the space surrounding the coating treatment device 1, a downdraft (downflow) of clean air maintained at a predetermined temperature (for example, 23°C) is formed. As a result, air is continuously blown from above to the substrate W during the coating process, as indicated by the white arrows at the top of FIG. 4 .

In the liquid film drying step, a part of the resist liquid R1 applied on the substrate W (a portion of the upper layer of the liquid film of the resist liquid R1) spreads from the center of the substrate W toward the outer circumferential end, and the substrate ( It scatters outward of W). Here, the resist liquid of this example contains a volatile solvent. Therefore, as indicated by the thick solid arrow at the top of FIG. 4 , the solvent of the resist liquid RL spread on the substrate W vaporizes. At this time, the descending airflow toward the substrate W from the upper position promotes vaporization of the solvent in the resist liquid R1, that is, drying of the liquid film of the resist liquid R1.

The heat capacity of the portion of the substrate W that does not contact the suction holding portion 11 (hereinafter referred to as a non-contact portion) is smaller than the heat capacity of the contact portion. Therefore, when vaporization of the solvent of the resist liquid R1 on the substrate W is accelerated, the temperature of the non-contacting portion is lowered than that of the contacting portion due to the effect of the heat of vaporization.

The lower the temperature of the resist liquid, the longer the time required for drying (hardening). Therefore, the resist liquid R1 spread on the non-contact portion is in a relatively easy state to flow when the substrate W rotates. However, in reality, even at the non-contact portion, vaporization of the solvent in the resist liquid R1 is promoted by generating a strong air current in the surrounding space at the outer peripheral end of the substrate W and at the portion near it, and the resist liquid R1 It is easy to harden.

Therefore, finally, as shown in the lower part of FIG. 4 , the thickness of the resist film R2 formed near the contact portion among the non-contact portions of the substrate W is smaller than the thickness of the liquid film formed on the contact portion. . Further, the thickness of the resist film formed near the outer peripheral end of the substrate W among the non-contact portions of the substrate W is equal to or greater than the thickness of the resist film formed on the contact portion of the substrate W.

In order to suppress the occurrence of non-uniformity in film thickness distribution in FIGS. 3 and 4 , in the present embodiment, a plurality of lower surface nozzles 17 are applied to the lower surface of the non-contact portion of the substrate W during a specific period in the liquid film drying step. A volatile rinse liquid is continuously supplied. The rinsing liquid has a temperature equal to or higher than the temperature of the suction holding unit 11 (room temperature in this example) at the time of contacting the substrate W. In the following description, this specific period is referred to as a liquid supply period. The liquid supply period is set within the period from the start of the liquid film drying step to the point at which the liquidity of the resist liquid on the substrate W is lost.

[3] A specific example of the coating treatment by the coating treatment device 1

5 is a diagram for explaining a specific example of an application process according to an embodiment of the present invention. In FIG. 5, the change in the rotational speed of the substrate W during the coating process by the coating apparatus 1 of FIG. 1 is represented by a graph. In the graph of FIG. 5 , the vertical axis represents the rotational speed of the substrate W, and the horizontal axis represents time.

Further, the rotational speed of the substrate W is adjusted by the control unit 30 controlling the rotation driving unit 13 of FIG. 1 . In addition, supply and stop of the resist liquid R1 to the upper surface S1 of the substrate W are performed by the controller 30 controlling the coating liquid supply system 22 of FIG. 1 . In addition, supply and stop of the rinsing liquid to the lower surface of the substrate W are performed by the controller 30 controlling the rinsing liquid supply system 18 of FIG. 1 .

In the initial state of the coating process by the coating apparatus 1, the unprocessed substrate W is suction-held in a horizontal posture by the suction holding unit 11 of FIG. 1 . At this time, the rotational speed of the substrate W is maintained at zero. Further, the cup 15 is positioned in the vertical direction so that the inner circumferential surface of the outer circumferential wall portion 15y of the cup 15 faces the outer circumferential end of the substrate W.

As shown in FIG. 5 , when the application process starts, the rotational speed of the substrate W first rises from 0 to s1. Also, the rotational speed of the substrate W is maintained at s1. Rotation speed s1 is set within the range of 0 rpm or more and 2000 rpm or less, for example. After that, the liquid film forming process is started from the time point t1. In addition, in the period from the start of the coating process to the time t1, a solvent may be supplied on the upper surface of the substrate W in order to modify the upper surface of the substrate W. This treatment is what is called pre-wetting.

In the liquid film forming step, a predetermined amount of resist liquid is supplied to the upper surface of the rotating substrate W during a period p1 from time point t1 to time point t4. At this time, the rotational speed of the substrate W rises from the time point t1 to the time point t3 and the time point t2 before t4 to s2 higher than s1. Rotation speed s2 is set within the range of 1000 rpm or more and 4500 rpm or less, for example. As a result, a core (chunk) of the resist liquid R1 having a constant spread is formed in the central portion of the upper surface of the substrate W. After a certain period of time has elapsed from the time point t2, the rotational speed of the substrate W returns to s1, and the rotational speed of the substrate W is maintained at s1 from the time point t3 to the time point t4. As a result, the core of the resist liquid R1 is shaped from the time point t3 to the time point t4.

Next, in a state where the supply of the resist liquid R1 to the substrate W is stopped, the rotational speed of the substrate W increases from time t4 to time t5 from s1 to s2. In addition, after a certain period of time has elapsed from the time point t5, the rotational speed of the substrate W is lowered from the time point t6 to s3, which is higher than s1 and lower than s2. Rotation speed s3 is set within the range of 400 rpm or more and 2500 rpm or less, for example.

From the above time t4 to the time t6, the resist liquid R1 spreads from the center of the substrate W toward the outer peripheral end. Thus, at the time point t6, a liquid film of the resist liquid R1 is formed on the entire upper surface of the substrate W, and the liquid film forming process is completed.

Next, the liquid film drying process is started. In the liquid film drying process, the rotational speed of the substrate W is maintained at s3 from the time point t6 to the time point t9. Here, at the time point t9, it is assumed that the entire resist liquid R1 on the substrate W is dried, and thus the liquid film drying step is completed.

In the initial stage of the liquid film drying process, a part of the resist liquid R1 supplied on the substrate W (a portion of the upper layer of the liquid film of the resist liquid R1) spreads from the center of the substrate W toward the outer circumferential end. , scattering to the outside of the substrate W. Thereafter, when a part of the solvent component of the resist liquid R1 on the substrate W evaporates and the fluidity of the resist liquid R1 is lost, the thickness of the liquid film of the resist liquid R1 on the substrate W becomes the resist film R2 ) is almost determined as the thickness of Therefore, in order to uniformize the film thickness distribution of the resist film R2 on the substrate W, the resist formed on the substrate W before the point at which the flowability of the resist liquid R1 on the substrate W is lost It is necessary to perform processing for adjusting the thickness of the film R2.

Therefore, in the example of FIG. 5 , after the time point t6 is defined as the time point at which the flowability of the resist liquid R1 on the substrate W is lost is defined as the time point t8, the period p2 from the time point t6 to the time point t7 before the time point t8 , the rinsing liquid is continuously supplied to the non-contact portion of the lower surface of the substrate W. This period p2 corresponds to the liquid supply period described above. In the following description, the time point t8 at which the flowability of the resist liquid R1 is lost is appropriately referred to as the time point at which the film thickness profile is determined.

As described above, the rinsing liquid has a temperature equal to or higher than the temperature of the suction holding unit 11 (room temperature in this example). Therefore, in the liquid supply period (period p2), the temperature of the non-contact portion of the substrate W rises temporarily. In areas where the temperature of the substrate W rises, the temperature of the resist liquid R1 rises and the fluidity of the resist liquid R1 decreases, so that the resist film R2 tends to become thick. This suppresses the thickness of the resist film R2 formed near the contact portion among the non-contact portions of the substrate W from being smaller than that of the resist film R2 formed on the contact portion.

Further, in the liquid film drying process, the rinsing liquid supplied to the lower surface of the substrate W vaporizes after the liquid supply period (period p2) and before the film thickness profile determining point (time point t8). As a result, the temperature of the non-contact portion of the substrate W, which has temporarily risen, is adjusted by the vaporization heat of the rinse liquid. In this way, the temperature of the non-contact portion of the substrate W is locally adjusted from the time point t6 to the time point t8. As a result, the film thickness distribution of the resist liquid R1 on the substrate W is uniform until the film thickness profile determining point in time at which the resist liquid R1 on the substrate W stops flowing (time point t8) has elapsed. can do

Further, consider a case in which a resist film R2 having a thickness of about 4.5 μm is formed on a substrate W using a resist liquid R1 having a viscosity of about 60 cP at room temperature (eg, 23° C.) . In this case, the length of the period of the liquid film drying step from the time point t6 to the time point t9 is set to, for example, 30 seconds or more and 90 seconds or less. Further, the length of the liquid supply period (period p2) from the time point t6 to the time point t7 is set to, for example, 1 second or more and 5 seconds or less.

During the period from time t8 to time t9 during the liquid film drying step, vaporization of the solvent component of the resist liquid R1 not flowing on the substrate W is continuously promoted. As a result, the resist liquid R1 on the substrate W is dried at the end of the liquid film forming process. That is, a resist film R2 is formed on the substrate W.

Next, from the time point t9 to the time point t11, the rinse liquid is supplied again to the non-contact portion of the lower surface of the substrate W. At this time, from the time point t9 to the time point t10 before the time point t11, the rotational speed of the substrate W decreases to s4 lower than s3, and is maintained for a certain period of time. Further, after that, the supply of the solvent to the substrate W is stopped, and the rotational speed of the substrate W is changed to s5, which is higher than s4 and lower than s3, and maintained for a certain period of time.

The processing from the time point t9 to the time point t11 described above is so-called back rinse. According to the back rinse, the resist liquid R1 or the solid material of the resist adhering to the lower surface of the substrate W is removed with a solvent.

Finally, from the time point t11 to the time point t12, the rotational speed of the substrate W is adjusted step by step in a state where no processing liquid (rinsing liquid, resist liquid, etc.) is supplied to the substrate W. As a result, the entire substrate W is dried, and the coating process is finished.

[4] End of liquid supply period (period p2)

As described above, the end point (time point t7) of the liquid supply period (period p2) is determined before the film thickness profile determination point (time point t8). Here, for example, in the example of FIG. 5 , in the case where the rotational speed of the substrate W is kept constant at s3 during the liquid film drying process, the overall fluidity of the resist liquid R1 on the substrate W is Before disappearing, interference fringes are generated by the resist liquid R1 flowing in the upper portion of the liquid film. This interference fringe can be visually recognized according to the rotational speed of the substrate W and the type of the resist liquid R1.

Therefore, the point at which the interference fringe generated on the substrate W disappears can be regarded as the point at which the film thickness profile is determined. Therefore, when it is possible to confirm the above interference fringes, the liquid supply period (period p2) ends after the liquid film drying process starts and before the interference fringes generated on the substrate W disappear. It is desirable to determine

[5] Start point of supply of rinsing liquid in liquid film drying process

The inventors of the present invention, in order to confirm whether or not there is a preferable time point as the starting point of supply of the rinse liquid in the liquid film drying process, resist films R2 were applied to three substrates W1, W2, and W3 by three coating methods. ) was formed. The three coating treatment methods are basically the same as the coating treatment method of FIG. In the following description, the starting point of supplying the rinsing liquid to the substrate W in the liquid film drying process is referred to as the rinsing start point.

Specifically, the present inventors performed the coating treatment on the substrate W1 by setting the time point 3 seconds after the start point of the liquid film drying step (time point t6 in FIG. 5 ) as the start point of rinsing. In addition, the present inventors performed the coating treatment on the substrate W2 by setting the time point 6 seconds after the start of the liquid film drying step as the start point of rinsing. In addition, the present inventors performed the coating treatment on the substrate W3 by setting the time point 9 seconds after the start of the liquid film drying step as the start point of rinsing. Substrates W1 to W3 have a common external shape. In addition, in the coating treatment of these substrates W1 to W3, the length of the liquid supply period was set to 6 seconds.

After that, the present inventors measured the film thickness distribution of the resist film R2 on a straight line passing through the center of each substrate with respect to the substrates W1 to W3 after the coating treatment. Fig. 6 is a diagram showing the film thickness distribution of the resist films R2 of the three substrates W1 to W3 subjected to the coating process for confirming the preferred rinsing starting point.

In FIG. 6, the film thickness distribution of the resist film R2 of the substrates W1 to W3 is represented by a graph. In the graph of Fig. 6, the vertical axis represents the film thickness of the resist film R2, and the horizontal axis represents the position on a straight line passing through the center of each of the substrates W1 to W3. In addition, on the horizontal axis, "0" represents the center of the substrates W1 to W3. Further, "150" represents one end of a straight line passing through the center of the substrates W1 to W3 on the surface of the substrates W1 to W3, and "-150" represents a straight line passing through the center of the substrates W1 to W3 on the surface of the substrates W1 to W3. represents the other end of

In the graph of FIG. 6 , a solid line indicates a film thickness distribution corresponding to the substrate W1, a dotted line indicates a film thickness distribution corresponding to the substrate W2, and a dotted line indicates a film thickness distribution corresponding to the substrate W3. In addition, in the graph of FIG. 6, the numerical value of "60" and "-60" is attached|subjected to the horizontal axis. A range CA from "60" to "-60" on the abscissa axis in FIG. 6 represents the portion (contact portion) of the substrates W1 to W3 held by the suction holding portion 11 .

As shown in FIG. 6 , the thickness of the resist film R2 of the substrates W1 to W3 locally increases in the vicinity of both ends of the contact portion in the non-contact portion. Here, comparing the thicknesses of the resist films R2 in the vicinity of both ends of the contact portions of the substrates W1 to W3, the thickness of the resist films R2 of the substrate W1 is equal to the thickness of the resist films R2 of the substrates W2 and W3. In comparison, it is close to the thickness of the central portion of the substrate. On the other hand, the thicknesses of the resist films R2 of the substrates W2 and W3 are substantially equal to each other.

According to these results, it can be seen that when the rinsing start point is set to 6 seconds or more after the start point of the liquid film drying process, it is difficult to uniformize the film thickness distribution of the resist film R2 formed on the substrate W. have. Therefore, the rinse start time is preferably set within the time from the start of the liquid film drying process until 5 seconds have elapsed, and more preferably set within the time from the start of the liquid film drying process until 3 seconds have elapsed. it was confirmed Accordingly, the thickness of the resist film R2 formed on the substrate W can be made more uniform.

[6] Length of liquid supply period

The inventors of the present invention applied resist films R2 to six substrates W11, W12, W13, W14, W15, and W16 by six coating methods in order to confirm whether there is a desirable time as the length of the liquid supply period. has formed The six coating methods are basically the same as those of FIG. 5 except for the fact that the liquid supply period in the liquid film drying step is different from each other.

Specifically, the inventors performed the coating process on the substrate W11 by setting the length of the liquid supply period (period p2 in FIG. 5) to 3 seconds, and by setting the length of the liquid supply period to 4 seconds on the substrate W12 by performing the coating process. did Further, the present inventors performed the coating process on the substrate W13 by setting the length of the liquid supply period to 5 seconds, and performed the coating process by setting the length of the liquid supply period by 6 seconds on the substrate W14. Further, the present inventors performed the coating process on the substrate W15 by setting the length of the liquid supply period to 9 seconds, and performed the coating process by setting the length of the liquid supply period by 12 seconds on the substrate W16. In addition, in the coating treatment of these substrates W11 to W16, the rinse start time was set to 3 seconds after the start time of the liquid film drying process (time t6 in FIG. 5).

After that, the present inventors measured the film thickness distribution of the resist film R2 on a straight line passing through the center of each substrate with respect to the substrates W11 to W16 after the coating treatment. Fig. 7 is a diagram showing the film thickness distribution of the resist films R2 of the six substrates W11 to W16 subjected to the coating process for confirming the desired length of the liquid supply period.

In FIG. 7, the film thickness distribution of the resist film R2 of the substrates W11 to W16 is represented by a graph. In the graph of FIG. 7, as in the example of FIG. 6, the vertical axis represents the film thickness of the resist film R2, and the horizontal axis represents the position on a straight line passing through the center of each of the substrates W11 to W16. In Fig. 7, the dotted line represents the film thickness distribution corresponding to the substrate W11, the dotted-dashed line represents the film thickness distribution corresponding to the substrate W12, and the thick solid line represents the film thickness distribution corresponding to the W13. Further, a thick one-dotted chain line represents a film thickness distribution corresponding to the substrate W14, a one-dot chain line represents a film thickness distribution corresponding to the substrate W15, and a solid line represents a film thickness distribution corresponding to the substrate W16. In the graph of FIG. 7 , as in the example of FIG. 6 , the range CA on the horizontal axis from “60” to “-60” is the substrate W11 held by the suction holding unit 11. ~ indicates the part (contact part) of W16.

As shown in Fig. 7, the thickness of the resist film R2 of the substrates W11 to W16 is substantially the same in the central portion of the substrate, and differs greatly in the vicinity of both ends of the contact portion in the non-contact portion. According to the example of FIG. 7 , the thickness of the resist film R2 in the vicinity of both ends of the contact portion is smaller as the substrate subjected to the coating process has a shorter liquid supply period. On the other hand, the thickness of the resist film R2 in the vicinity of both ends of the contact portion is greater in the case of a substrate subjected to a coating process having a longer liquid supply period. As a result, large nonuniformity was confirmed in the film thickness distribution of the resist film R2 between the substrates W11 to W16.

Fig. 8 is a diagram showing the uniformity of the film thickness distribution of the resist films R2 of the six substrates W11 to W16 on which the coating process was performed in order to confirm the desired length of the liquid supply period. In Fig. 8, the uniformity of the film thickness distribution of the resist films R2 of the substrates W11 to W16 is represented by a graph.

In the graph of FIG. 8 , the vertical axis represents uniformity, and the abscissa axis represents the types of substrates (substrates W11 to W16). In addition, in the graph of FIG. 8 , the range and 3σ calculated as uniformity based on the thicknesses of a plurality of portions of the resist film R2 measured for each of the substrates W11 to W16 are the bands of the hatching and dot patterns ( bar), respectively. The range and 3σ shown in FIG. 8 indicate that the film thickness distribution of the resist film R2 is more uniform as the value is smaller, and that the film thickness distribution of the resist film R2 is larger as the value is larger.

7 and 8, the film thickness distribution of the resist film R2 of the substrate W14 has the highest uniformity among the film thickness distributions of the plurality of substrates W11 to W16. less) was confirmed. That is, it was confirmed that it was possible to make the film thickness distribution of the resist film R2 most uniform by performing the coating process by setting the length of the liquid supply period to 6 seconds. On the other hand, it was confirmed that the film thickness distribution of the resist film R2 of the substrate W11 had the lowest uniformity (largest unevenness) among the film thickness distributions of the plurality of resist films R2 of the plurality of substrates W11 to W16.

As described above, it is understood that the film thickness distribution of the resist film R2 formed on the substrate differs greatly depending on the length of the liquid supply period set during the coating process. Therefore, the length of the liquid supply period is preferably determined more appropriately based on simulation or experiment so that the film thickness distribution of the resist film R2 becomes more uniform.

[7] Rinse solution supply position

In the coating apparatus 1 of FIG. 1 , each of the plurality of lower surface nozzles 17 is disposed near the outer circumferential end of the suction holder 11 in a plan view. Therefore, the rinsing liquid discharged from each lower surface nozzle 17 is supplied to a portion of the non-contact portion of the substrate W that is close to the outer circumferential end of the suction holder 11 and far from the outer circumferential end of the substrate W.

In the following description, among the non-contacting portions of the substrate W, a portion far from the outer circumferential end of the suction holding portion 11 and close to the outer circumferential end of the substrate W is referred to as an outer annular portion. Further, the outer annular portion is positioned inward, for example, by about 50 mm from the outer circumferential end of the substrate W when the substrate W has a diameter of 300 mm.

The inventors of the present invention, in order to check whether it is possible to adjust the film thickness of the resist film R2 when the rinse liquid is supplied to the outer annular portion, a plurality of lower surface nozzles ( 17) has been changed. Specifically, the present inventors arranged each lower surface nozzle 17 so that the rinse liquid discharged from the plurality of lower surface nozzles 17 is supplied to the outer annular portion of the substrate W, in a planar view, the suction holding portion 11 ) was placed at a position closer to the inner peripheral end of the cup 15 than the outer peripheral end. In addition, the present inventors use the coating treatment apparatus 1 in which the positions of the plurality of lower surface nozzles 17 are changed, and eight substrates (W21, W22, W23, W24, W25, W26, A resist film R2 was formed on W27 and W28. The eight coating treatment methods are basically the same as the coating treatment method of FIG. 5 except that the liquid supply period in the liquid film drying step is different from each other.

Specifically, the inventors performed the coating process on the substrate W21 by setting the length of the liquid supply period (period p2 in FIG. 5) to 1 second, and by setting the length of the liquid supply period by 2 seconds on the substrate W22 to perform the coating process. did Further, the present inventors performed the coating process on the substrate W23 by setting the length of the liquid supply period to 3 seconds, and performed the coating process by setting the length of the liquid supply period by 4 seconds on the substrate W24. Further, the present inventors performed the coating process on the substrate W25 by setting the length of the liquid supply period to 5 seconds, and performed the coating process by setting the length of the liquid supply period by 6 seconds on the substrate W26. Further, the present inventors performed the coating process on the substrate W27 by setting the length of the liquid supply period to 9 seconds, and performed the coating process on the substrate W28 by setting the length of the liquid supply period by 12 seconds. In addition, in the coating treatment of these substrates W21 to W28, the rinse start time was set to 3 seconds after the start time of the liquid film drying process (time t6 in FIG. 5).

After that, the present inventors measured the film thickness distribution of the resist film R2 on a straight line passing through the center of each substrate with respect to the substrates W21 to W28 after the coating treatment. Fig. 9 shows eight substrates W21 to W28 subjected to a coating process for checking whether or not the film thickness of the resist film R2 can be adjusted by supplying the rinse liquid to the outer annular portion of the substrate W. It is a figure which shows the film thickness distribution of the resist film R2.

In FIG. 9, the film thickness distribution of the resist film R2 of the substrates W21 to W28 is represented by a graph. In the graph of FIG. 9, as in the example of FIG. 6, the vertical axis represents the film thickness of the resist film R2, and the horizontal axis represents the position on a straight line passing through the center of each of the substrates W21 to W28. In Fig. 9, the dotted line represents the film thickness distribution corresponding to the substrate W21, the dotted line represents the film thickness distribution corresponding to the substrate W22, the dotted line represents the film thickness distribution corresponding to the substrate W23, and the solid line represents the substrate W23. The film thickness distribution corresponding to W24 is shown. Further, the thick dotted line represents the film thickness distribution corresponding to the substrate W25, the thick two-dot chain line represents the film thickness distribution corresponding to the substrate W26, the thick dotted line represents the film thickness distribution corresponding to the substrate W27, and the thick solid line represents the substrate W26. The film thickness distribution corresponding to W28 is shown. In the graph of FIG. 9 , as in the example of FIG. 6 , the range CA of “60” to “-60” on the abscissa axis is held by the adsorption holder 11 of the substrate W21 Indicates the part (contact part) of ~W28.

As shown in Fig. 9, the thicknesses of the resist films R2 formed on the non-contact portions of the substrates W21 to W28 are different from each other. Specifically, according to the graph of FIG. 9 , the thickness of the resist film R2 in the non-contact portion is smaller for the substrate subjected to the coating process with a shorter liquid supply period, and the coating process with a longer liquid supply period is performed. The larger the substrate, the larger it is. Further, the difference between these thicknesses increases as the outer circumferential end of the substrate W is approached. Thus, even when the rinse liquid is supplied to the outer annular portion of the substrate W, the film thickness of the resist film R2 formed on the non-contact portion of the substrate W is adjusted by appropriately adjusting the length of the liquid supply period. It has been confirmed that this is possible.

[8] Effect

(1) In the coating apparatus 1 according to the present embodiment, a resist liquid is supplied to the upper surface of the rotating substrate W during coating processing. The resist liquid R1 supplied to the upper surface of the substrate W flows over the upper surface of the substrate W due to centrifugal force. During the liquid supply period, the rinsing liquid is supplied to the non-contact portion of the substrate W. During the liquid supply period, at least a part of the rinsing liquid supplied to the substrate W is vaporized until the film thickness profile determining point elapses. In this case, the temperature of the non-contact portion of the substrate W is adjusted with high efficiency by the heat of vaporization generated along with the vaporization of the rinse liquid.

By appropriately adjusting the temperature of the non-contact portion of the substrate W, it is possible to suppress local changes in the movement state of the resist liquid flowing in the radial direction of the substrate W. Accordingly, the thickness of the resist film R2 formed on the substrate W can be made uniform. The liquid supply period is shorter than the period between when the supply of the resist liquid R1 to the substrate W is stopped and until the film thickness profile is determined. Therefore, in order to uniformize the thickness of the resist film R2, it is not necessary to continuously supply the rinse liquid to the substrate W during the period in which the resist liquid R1 flows on the substrate W. As a result, it becomes possible to uniformize the film thickness distribution at low cost regardless of the thickness of the resist film R2.

(2) As described above, the point at which the interference fringe generated on the substrate W disappears can be regarded as the point at which the film thickness profile is determined. Therefore, the liquid supply period can be easily and appropriately set by confirming in advance the occurrence and disappearance of the interference fringes.

(3) In the coating process by the coating apparatus 1 according to the present embodiment, the length of the liquid supply period is preferably 10 seconds or less. Thereby, consumption of the rinse liquid can be further reduced. Therefore, it becomes possible to uniformize the film thickness distribution of the resist film R2 at a lower cost.

(4) As described above, it is preferable that the rinse start time is determined so as to be within 5 seconds from the start time of the liquid film forming step. In this case, it becomes possible to more appropriately adjust the temperature of the substrate W. Accordingly, the film thickness distribution of the resist film R2 formed on the substrate W can be more uniform.

(5) In the coating apparatus 1 of FIG. 1, the rinse liquid discharged from each of the plurality of lower surface nozzles 17 is close to the outer peripheral end of the suction holding portion 11 among the non-contact parts of the substrate W, Further, it is supplied to a position far from the outer circumferential end of the substrate W. That is, the rinsing liquid is supplied to a region between the contact portion of the substrate W and the outer periphery of the lower surface of the substrate W. Accordingly, the temperature of the non-contact portion of the substrate W located in the vicinity of the contact portion can be more appropriately adjusted.

[9] Other embodiments

(1) In the coating apparatus 1 according to the above embodiment, the plurality of lower surface nozzles 17 are fixed to the housing of the coating apparatus 1, but the present invention is not limited to this. 10 is a schematic cross-sectional view showing an example of a configuration of a coating device 1 according to another embodiment. The coating apparatus 1 of FIG. 10 has the same configuration as the coating apparatus 1 of FIG. 1 except that the lower surface of the coating apparatus 1 includes a nozzle driving unit 81 .

As shown by thick arrows in FIG. 10 , the lower surface nozzle drive unit 81 is configured to be capable of moving each of the plurality of lower surface nozzles 17 in the radial direction of the substrate W, and by the control unit 30 controlled According to this configuration, the supply position of the rinse liquid on the lower surface of the substrate W can be adjusted according to various conditions such as the type of substrate W and the type of resist liquid. In addition, the supply position of the rinse liquid may be moved during the liquid supply period. Accordingly, the degree of freedom in adjusting the temperature of the substrate W is improved.

(2) In the coating apparatus 1 according to the above embodiment, the temperature of the rinse liquid supplied to the substrate W from the plurality of lower surface nozzles 17 is equal to or higher than the temperature of the suction holding unit 11, but the present invention is not limited to this. The temperature of the rinsing liquid supplied to the substrate W may be lower than the temperature of the suction holding unit 11 .

Further, the coating apparatus 1 may be configured such that the temperature of the rinsing liquid supplied to the substrate W can be adjusted. 11 is a schematic cross-sectional view showing another example of the configuration of a coating device 1 according to another embodiment. The coating apparatus 1 of FIG. 11 has the same configuration as the coating apparatus 1 of FIG. 1 except that the coating apparatus 1 includes a temperature controller 82 .

As shown in FIG. 11 , the temperature adjusting unit 82 is configured to adjust the temperature of the rinsing liquid supplied from the rinsing liquid supply system 18 to the lower surface nozzle 17 to a preset temperature, and the control unit 30 is controlled by According to this configuration, the temperature of the rinse liquid supplied to the lower surface of the substrate W can be appropriately adjusted according to various conditions such as the type of substrate W and the type of resist liquid.

(3) In the coating process according to the above embodiment, the rinse liquid is continuously supplied to the lower surface of the substrate W during the liquid supply period, but the present invention is not limited to this. The supply of the rinsing liquid to the lower surface of the substrate W may be intermittently performed during the liquid supply period.

(4) In the coating treatment according to the above embodiment, a solvent is used as a rinse liquid to adjust the temperature of the non-contact portion of the substrate W, but the present invention is not limited to this. As the rinsing liquid for adjusting the temperature of the non-contact portion of the substrate W, pure water incapable of dissolving the resist film R2 may be used instead of a solvent.

(5) In the coating apparatus 1 according to the above embodiment, four lower surface nozzles 17 are provided to supply a rinse liquid to the lower surface of the substrate W, but the present invention is not limited thereto. The number of lower surface nozzles 17 supplying the rinse liquid to the lower surface of the substrate W may be one, two or three. Alternatively, the number of lower surface nozzles 17 may be five or more.

(6) In the coating apparatus 1 according to the above embodiment, the resist liquid R1 is supplied to the substrate W as the coating liquid, but the present invention is not limited to this. In the coating apparatus 1, the coating liquid for the antireflection film may be supplied to the substrate W. Alternatively, in the coating apparatus 1, a coating liquid for a SOC (Spin On Carbon) film, a SOG (Spin On Glass) film, or a SiARC (Si-rich Anti Reflective Coating) film may be supplied to the substrate W.

(7) In the coating apparatus 1 according to the above embodiment, a plurality of lower surface nozzles 17 are used as a rinse liquid supply device for back rinse, but the present invention is not limited to this. In addition to the plurality of lower surface nozzles 17 described above, the coating processing apparatus 1 may have one or a plurality of nozzles exclusively for back rinse. In this case, the plurality of lower surface nozzles 17 can be installed at more suitable positions for adjusting the temperature of the substrate W. In addition, one or more nozzles dedicated to the back rinse can be provided at more suitable positions for removing the resist liquid R1 or the resist film R2 adhering to the lower surface of the substrate W. As a result, the uniformity of the film thickness of the resist film R2 formed on the substrate W can be improved, and the lower surface of the substrate W can be kept cleaner.

[10] Correspondence between each element of the claim and each element of the embodiment

Hereinafter, examples of correspondence between each constituent element of the claims and each element of the embodiment will be described. In the above embodiment, the contact portion of the substrate W is an example of the lower surface central portion of the substrate, the rotation holding device 10 is an example of the rotation holding portion, the liquid supply device 20 is an example of the coating liquid supply portion, and the substrate ( The non-contact portion of W) is an example of the bottom annular portion of the substrate, and the plurality of bottom surface nozzles 17 and the rinse liquid supply system 18 are examples of the rinse liquid supply unit.

In the liquid film forming process, the time point at which the supply of the resist liquid R1 is stopped (time point t4 in FIG. 5 ) is an example of the first time point, and the time point at which the film thickness profile is determined (time point t8 in FIG. 5 ) is an example of the second time point. If yes, the control unit 30 is an example of the control unit, the application processing device 1 is an example of the application processing device, the time point at which the liquid film forming process ends and the liquid film drying process starts (time t6 in FIG. 5 ) This is an example of the third viewpoint. As each component of the claim, various other elements having the configuration or function described in the claim may be used.

Claims (10)

Rotating the substrate to which the central portion of the lower surface of the substrate is sucked around a vertical axis while maintaining it in a horizontal position by a rotation holding unit;
supplying a coating liquid to the upper surface of the substrate rotated by the rotation holding unit;
In the state in which the substrate held by the rotation holding unit rotates, after the first time point at which the supply of the coating solution is finished, the second time point during the liquid flow period until the second time point at which the fluidity of the coating solution on the substrate is lost. and supplying a volatile rinsing liquid to at least a part of an annular portion of the lower surface surrounding a central portion of the lower surface of the lower surface of the substrate rotated by the rotation holding unit during the previous liquid supply period. The method of claim 1,
The second point in time is a point in time when interference fringes generated on the surface of the coating liquid supplied to the upper surface of the substrate disappear after the first point in time. According to claim 1 or claim 2,
The length of the liquid supply period is 10 seconds or less, the coating treatment method. According to claim 1 or claim 2,
The rotating step includes rotating the substrate so that the coating liquid supplied to the upper surface of the substrate covers the entire upper surface of the substrate over a third time point before the second time point after the lapse of the first time point,
The start time of the liquid supply period is determined within a time period from the third time point until 5 seconds elapse. According to claim 1 or claim 2,
The lower surface annular portion is located between the lower surface peripheral portion and the lower surface central portion of the annular lower surface including the outer circumferential end of the substrate among the lower surface of the substrate rotated by the rotation holding unit. A rotation holding unit that rotates the substrate around a vertical axis while holding the substrate in a horizontal position by adsorbing a central portion of the lower surface of the substrate;
A coating liquid supply unit for supplying a coating liquid to the upper surface of the substrate rotated by the rotation holding unit;
a rinse liquid supply unit for supplying a volatile rinse liquid to at least a part of an annular portion of a lower surface of the lower surface of the substrate rotated by the rotation holding unit and surrounding a central portion of the lower surface;
In a state in which the substrate held by the rotation holding unit rotates, the coating liquid is supplied to the upper surface of the substrate, and the second timing when the fluidity of the coating liquid on the substrate is lost after the first timing when the supply of the coating liquid is finished A controller for controlling the rotation holding unit, the coating liquid supply unit, and the rinse liquid supply unit so that the rinse liquid is supplied to the lower annular portion of the lower surface of the substrate during a liquid supply period before the second point in time during the liquid flow period to application processing device. The method of claim 6,
The second point in time is a point in time when interference fringes generated on the surface of the coating liquid supplied to the upper surface of the substrate disappear after the first point in time. According to claim 6 or claim 7,
The coating treatment device, wherein the length of the liquid supply period is 10 seconds or less. According to claim 6 or claim 7,
The control unit controls the rotation holding unit so that the coating liquid supplied to the upper surface of the substrate covers the entire upper surface of the substrate over a third time point before the second time point after the first time point has elapsed,
The application processing apparatus, wherein the start time of the liquid supply period is determined within a time period from the third time point until 5 seconds elapse. According to claim 6 or claim 7,
The lower surface annular portion is located between the lower surface periphery of the annular lower surface including the outer peripheral end of the substrate among the lower surface of the substrate rotated by the rotation holding unit and the lower surface central portion.

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