JP5533178B2 - Silicon wafer cleaning agent - Google Patents

Description

  The present invention relates to a technique for cleaning a silicon substrate (wafer) for the purpose of improving the manufacturing yield of a device having a circuit pattern that is fine and has a high aspect ratio, particularly in the manufacture of semiconductor devices.

  In semiconductor devices for networks and digital home appliances, higher performance, higher functionality, and lower power consumption are required. For this reason, circuit patterns are being miniaturized, and accordingly, the particle size that causes a reduction in manufacturing yield is also miniaturized. As a result, a cleaning process for removing fine particles is frequently used, and as a result, the cleaning process accounts for 30 to 40% of the entire semiconductor manufacturing process.

  On the other hand, in the conventional cleaning with the mixed ammonia cleaning agent, the damage to the wafer due to the basicity becomes a problem as the circuit pattern is miniaturized. For this reason, replacement with, for example, a dilute hydrofluoric acid-based cleaning agent with less damage is in progress.

  Thus, although the problem of damage to the wafer due to cleaning has been improved, the problem due to the increase in the aspect ratio of the pattern accompanying the miniaturization of the semiconductor device has become apparent. That is, after cleaning or rinsing, a phenomenon that the pattern collapses when the gas-liquid interface passes through the pattern causes a significant decrease in yield.

  This pattern collapse occurs when the wafer is pulled up from the cleaning liquid or the rinse liquid. This is said to be caused by a difference in residual liquid height between a portion where the aspect ratio of the pattern is high and a portion where the aspect ratio is low, thereby causing a difference in capillary force acting on the pattern.

  For this reason, if the capillary force is reduced, it can be expected that the difference in capillary force due to the difference in the residual liquid height will be reduced and the pattern collapse will be eliminated. The magnitude of the capillary force is the absolute value of P obtained by the following formula. From this formula, it is expected that the capillary force can be reduced by reducing γ or cos θ.

P = 2 × γ × cos θ / S (γ: surface tension, θ: contact angle, S: pattern dimension)
Patent Document 1 discloses a technique for substituting the cleaning liquid from water to 2-propanol before passing through the gas-liquid interface as a technique for reducing γ and suppressing pattern collapse. However, while this method is effective for preventing pattern collapse, a solvent such as 2-propanol having a small γ tends to have a small normal contact angle and, as a result, tends to increase cos θ. Therefore, it is said that there is a limit, for example, the aspect ratio of the pattern that can be handled is 5 or less.

  Patent Document 2 discloses a technique for resist patterns as a technique for reducing cos θ to suppress pattern collapse. This method is a method of suppressing pattern collapse by setting cos θ close to 0 and reducing the capillary force to the limit by setting the contact angle near 90 °.

  However, since the disclosed technique is intended for a resist pattern, it modifies the resist itself, and can be finally removed together with the resist. Therefore, it is necessary to assume a method for removing the treatment agent after drying. Is not applicable to this purpose.

In addition, as a technique for preventing pattern collapse of a semiconductor device, use of a critical fluid, use of liquid nitrogen, or the like has been proposed. However, all have certain effects, but unlike conventional cleaning processes, processing in a closed system or batch is necessary, and thus there is a cost problem such as throughput.
JP 2008-198958 A Japanese Patent Laid-Open No. 5-299336

  At the time of manufacturing a semiconductor device, the surface of the silicon wafer is a surface having a fine uneven pattern. An object of the present invention is to provide a silicon wafer cleaning agent for improving a cleaning process that easily induces pattern collapse in a method for manufacturing a silicon wafer having a fine uneven pattern on the surface.

  The cleaning agent for silicon wafers of the present invention is a cleaning agent for silicon wafers having a fine uneven pattern on the surface, and the cleaning agent for silicon wafers repels at least an aqueous cleaning solution and at least the recesses of the uneven pattern during the cleaning process. The water-repellent cleaning liquid comprises a water-repellent compound containing a reactive group capable of chemically bonding to Si of the silicon wafer and a hydrophobic group, and an organic solvent containing at least an alcohol solvent. It is mixed and contained.

  In the cleaning agent of the present invention, each cleaning solution is used independently, and at least two types of cleaning solutions are used.

  In the present invention, the water repellency means reducing the surface energy of the article surface, and interacting between water or other liquid and the article surface (interface), for example, hydrogen bonding, intermolecular force, etc. It means to reduce. In particular, the effect of reducing the interaction with water is great, but it has the effect of reducing the interaction with a mixed liquid of water and a liquid other than water or a liquid other than water. By reducing the interaction, the contact angle of the liquid with the article surface can be increased.

  The aqueous cleaning liquid contained in the silicon wafer cleaning agent of the present invention is supplied to the concave portions of the surface after the surface of the silicon wafer has a fine uneven pattern when cleaning the silicon wafer on which the uneven pattern is formed. Further, the water repellent cleaning liquid may be supplied to the silicon wafer after being supplied to the silicon wafer. Furthermore, the water-repellent cleaning liquid and the water-based cleaning liquid may be supplied to the silicon wafer surface while replacing the different cleaning liquid in a state where a cleaning liquid different from the cleaning liquid is held in the concave portion of the silicon wafer surface.

  The cleaning agent for silicon wafers of the present invention is composed of a plurality of cleaning liquids, and is used while replacing the cleaning liquid holding the recesses with other cleaning liquids. Removed.

  While the silicon wafer surface is being cleaned with the silicon wafer cleaning agent of the present invention, the recesses on the silicon wafer surface temporarily hold the water-repellent cleaning liquid. By this holding, the concave portion becomes a surface state that has been made water-repellent by the water-repellent compound. The water-repellent surface state of the present invention does not necessarily have to be formed continuously, and does not necessarily have to be formed uniformly, but it can provide more excellent water repellency, In addition, it is more preferable that they are formed uniformly.

In the present invention, since the water repellent compound includes a reactive site capable of chemically bonding with Si of the silicon wafer, the water repellent surface state is maintained until the cleaning agent is removed from the recess. It can be held on the surface. Therefore, when the cleaning liquid is removed, that is, when it is dried, the surface of the recess is in a water-repellent surface state, so that the capillary force on the surface of the recess is reduced and pattern collapse is less likely to occur. . When it is assumed that water is held in the concave portion on the surface of the water-repellent silicon wafer, the capillary force on the concave surface is 2.1 MN / m ² or less, so that the capillary force is small and pattern collapse hardly occurs. Therefore, it is preferable. The water-repellent surface state can be removed by at least one treatment selected from light irradiation, heating a silicon wafer, and exposing the silicon wafer to ozone.

  In addition, the water-repellent cleaning liquid is mixed with a water-repellent compound containing a reactive site that can be chemically bonded to Si of the silicon wafer and a hydrophobic group, and an alcohol solvent, so that the surface of the recess can be formed in a short time. It becomes easy to obtain a sufficiently water-repellent surface state.

  In the water-repellent cleaning liquid, when the water-repellent compound is less than 0.1% by mass with respect to 100% by mass of the total amount of the water-repellent cleaning liquid, it is difficult to make the surface of the recess sufficiently surface repellent. On the other hand, if it exceeds 99.9% by mass, the effect of alcohol (which can sufficiently repel the surface of the recess in a short time) becomes small.

  Since the cleaning agent for silicon wafers of the present invention exhibits excellent pattern collapse prevention properties, the use of the cleaning agent reduces the throughput of the cleaning process in the method for manufacturing a silicon wafer having a fine uneven pattern on the surface. Will be improved. Therefore, the method for producing a silicon wafer having a fine concavo-convex pattern on the surface, which is performed using the silicon wafer cleaning agent of the present invention, has high productivity.

  The cleaning agent of the present invention can cope with a concavo-convex pattern having an aspect ratio of, for example, 7 or more, which is expected to become higher in the future, and can reduce the cost of production of higher-density semiconductor devices. In addition, the conventional apparatus can be applied without significant change, and as a result, can be applied to the manufacture of various semiconductor devices.

It is a figure which shows the schematic diagram when the silicon wafer 1 made into the surface which has the fine uneven | corrugated pattern 2 on the surface is perspective. FIG. 2 shows a part of the a-a ′ cross section in FIG. 1. The schematic diagram of the state in which the recessed part 4 hold | maintained the washing | cleaning liquid 8 in the washing | cleaning process is shown. It is a figure which shows the schematic diagram of the state by which the aqueous cleaning liquid was hold | maintained at the recessed part 4 of the surface state made water-repellent.

A suitable cleaning method for a silicon wafer having a fine concavo-convex pattern on the surface using the silicon wafer cleaning agent of the present invention,
After making the surface of the silicon wafer into a surface having a fine concavo-convex pattern, the aqueous cleaning liquid is applied to the surface, and the aqueous cleaning liquid held in the recess is replaced with a cleaning liquid A different from the aqueous cleaning liquid. It has the process of removing the process cleaning agent which hold | maintains the water-repellent cleaning liquid for making the recessed surface of a process uneven | corrugated pattern water-repellent in this recessed part.

  Further, after the step of holding the water-repellent cleaning liquid in the recess, the water-repellent cleaning liquid held in the recess may be replaced with a cleaning liquid B different from the water-repellent cleaning liquid. Further, it is more preferable to perform a step of holding an aqueous cleaning liquid composed of an aqueous solution in the concave portion through the replacement with the different cleaning liquid B.

In addition, the step of removing the cleaning agent,
Removing the cleaning liquid retained in the recess from the recess by drying;
The method includes performing at least one treatment selected from irradiating the surface of the silicon wafer with light, heating the silicon wafer, and exposing the silicon wafer to ozone.

  Further, in the step of removing the cleaning agent, the step of removing the cleaning liquid held in the concave portion from the concave portion by drying, irradiating the silicon wafer surface with light, heating the silicon wafer, and exposing the silicon wafer to ozone During the step of performing at least one treatment selected from the above, the cleaning liquid B may be provided in the recess, and the cleaning liquid B may be removed by drying, or the aqueous solution may be provided in the recess after the cleaning liquid B is provided. A step of holding an aqueous cleaning solution consisting of and removing the aqueous cleaning solution by drying may be performed.

  The water-repellent cleaning liquid is 0.1 to 99.9% by weight, preferably 0.2 to 75% by weight, more preferably 0.3 to 50% by weight with respect to 100% by weight of the total amount of the water-repellent cleaning liquid. A water repellent compound and an organic solvent containing at least an alcohol solvent are mixed and contained. By containing 0.1 to 99.9% by mass of the water-repellent compound, the surface of the concave portion can be easily converted into a water-repellent surface state in a short time.

  The water repellent cleaning liquid contains at least an alcohol solvent. When the alcohol solvent is present, the reaction between the water-repellent compound and Si of the silicon wafer is accelerated, and the surface of the concave portion of the silicon wafer is easily brought into a sufficiently water-repellent surface state in a short time.

  Examples of the alcohol solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, iso-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1 -Alcohol consisting of an alkyl group such as octanol and one hydroxyl group, ethylene glycol, glycerin, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, diethylene glycol monoethyl Polyhydric alcohols such as ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether And derivatives thereof.

  The alcohol solvent is preferably an alcohol composed of an alkyl group and one hydroxyl group. In this case, it becomes easy to make the surface of the concave portion of the silicon wafer into a sufficiently water-repellent surface state in a short time. Further, among alcohols composed of an alkyl group and one hydroxyl group, primary alcohol or secondary alcohol is particularly preferable because it easily makes the surface of a concave portion of a silicon wafer sufficiently water-repellent in a short time. .

  The alcohol solvent preferably has 10 or less carbon atoms, and particularly preferably 6 or less carbon atoms. Furthermore, the alcohol solvent may be a single one or a mixture of a plurality of alcohol solvents.

  When the alcohol solvent is 0.1 to 10000 parts by mass, particularly 0.5 to 5000 parts by mass with respect to 100 parts by mass of the total amount of the water-repellent compound, the concave surface of the silicon wafer is sufficiently water-repellent in a short time. This is preferable because it is easy to obtain a surface state.

  The water-repellent cleaning liquid may contain an organic solvent other than the alcohol solvent. Since the water-repellent compound easily reacts with a protic solvent, it is particularly preferable to use an aprotic solvent as the organic solvent other than the alcohol solvent because the water-repellent property is easily developed in a short time. The aprotic solvent is both an aprotic polar solvent and an aprotic apolar solvent. Examples of such aprotic solvents include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, polyhydric alcohol derivatives having no hydroxyl group, and nitrogen-containing compounds having no N—H bond. A compound solvent etc. are mentioned. Examples of the hydrocarbons include toluene, benzene, xylene, hexane, heptane, and octane. Examples of the esters include ethyl acetate, propyl acetate, butyl acetate, and ethyl acetoacetate, and the ether. Examples of such classes include diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, dioxane and the like, and examples of the ketones include acetone, acetylacetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, cyclohexanone, isophorone, and the like. Examples of the halogen-containing solvent include perfluorocarbons such as perfluorooctane, perfluorononane, perfluorocyclopentane, perfluorocyclohexane, hexafluorobenzene, 1, 1, 1, Hydrofluorocarbons such as 3-pentafluorobutane, octafluorocyclopentane, 2,3-dihydrodecafluoropentane, Zeolora H (manufactured by Nippon Zeon), methyl perfluoroisobutyl ether, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, Hydrofluoroethers such as ethyl perfluoroisobutyl ether, Asahiklin AE-3000 (manufactured by Asahi Glass), Novec HFE-7100, Novec HFE-7200, Novec 7300, and Novec 7600 (all from 3M), chlorocarbons such as tetrachloromethane, chloroform Hydrochlorocarbons such as chlorofluorocarbons such as dichlorodifluoromethane, 1,1-dichloro-2,2,3,3,3-pe Tafluoropropane, 1,3-dichloro-1,1,2,2,3-pentafluoropropane, 1-chloro-3,3,3-trifluoropropene, 1,2-dichloro-3,3,3- Examples include hydrochlorofluorocarbons such as trifluoropropene, perfluoroethers, perfluoropolyethers, etc. Examples of the sulfoxide solvents include dimethyl sulfoxide, and examples of polyhydric alcohol derivatives having no hydroxyl group include Diethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol di Examples of nitrogen-containing compound solvents having no N—H bond include N, N-dimethylformamide, N, N-dimethylacetamide, N, and the like. -Methyl-2-pyrrolidone, triethylamine, pyridine and the like.

  In addition, it is preferable to use a nonflammable organic solvent other than the alcohol solvent because the water-repellent cleaning liquid becomes nonflammable or has a high flash point, which reduces the risk of the water-repellent cleaning liquid. Many halogen-containing solvents are nonflammable, and the nonflammable halogen-containing solvent can be suitably used as a nonflammable organic solvent.

  In this case, the organic solvent other than the alcohol solvent is preferably 2 to 95000 times, more preferably 4 to 50000 times in mass ratio with respect to the alcohol solvent.

  Further, when the water-repellent cleaning liquid is supplied to the wafer while rotating the wafer, when the boiling point of the organic solvent is low, the cleaning liquid is easily dried before the water-repellent cleaning liquid wets and spreads over the entire surface of the wafer. Further, when the boiling point is high, the viscosity tends to increase. For this reason, it is preferable to use the organic solvent having a boiling point of 70 to 220 ° C. As such a solvent, alcohol is particularly preferable, and considering the cost and solubility with other cleaning liquids (ease of substitution), the alcohol includes 1-propanol, 2-propanol, and organic solvents other than the alcohol. In diethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, ethylene glycol diethyl ether, ethylene glycol dimethyl ether, and cyclohexanone are preferable.

  In the pattern formation process in which the surface of the silicon wafer has a fine concavo-convex pattern, first, after applying a resist to the wafer surface, the resist is exposed through a resist mask, and the exposed resist is not exposed. The resist having a desired concavo-convex pattern is produced by etching away the resist. Moreover, the resist which has an uneven | corrugated pattern can be obtained also by pressing the mold which has a pattern to a resist. Next, the wafer is etched. At this time, the concave portion of the resist pattern is selectively etched. Finally, when the resist is removed, a silicon wafer having a fine uneven pattern is obtained.

  In addition, as a silicon wafer, a silicon oxide film such as a natural oxide film, a thermal oxide film, or a gas phase synthetic film (such as a CVD film) is formed on the surface, or when the above uneven pattern is formed, the uneven pattern Also included are those in which at least a part of the silicon oxide is silicon oxide. Further, silicon or silicon nitride can be used because its outermost surface is naturally oxidized by contact with water or air to form a silicon oxide film on the surface.

  Further, the surface of the silicon and / or silicon oxide can be water-repellent even for a wafer composed of a plurality of components including silicon and / or silicon oxide. As a wafer composed of the plurality of components, silicon and / or a silicon oxide film such as a natural oxide film, a thermal oxide film, a vapor-phase synthesis film (such as a CVD film) formed on the surface, or an uneven pattern is used. When formed, at least a part of the concave / convex pattern includes silicon and / or silicon oxide.

  After the surface of the silicon wafer has a fine uneven pattern, the surface is cleaned with an aqueous cleaning solution, and the aqueous cleaning solution is removed by drying or the like. If the width of the concave portion is small and the aspect ratio of the convex portion is large, the pattern collapses. Is likely to occur. The concavo-convex pattern is defined as shown in FIGS. FIG. 1 shows a schematic view when a silicon wafer 1 whose surface is a surface having a fine uneven pattern 2 is viewed, and FIG. 2 shows a part of aa ′ cross section in FIG. is there. As shown in FIG. 2, the width 5 of the concave portion is indicated by the interval between the convex portion 3 and the convex portion 3, and the aspect ratio of the convex portion is expressed by dividing the height 6 of the convex portion by the width 7 of the convex portion. Is done. Pattern collapse in the cleaning process tends to occur when the width of the recess is 70 nm or less, particularly 45 nm or less, and the aspect ratio is 4 or more, particularly 6 or more.

  In a preferred embodiment of the present invention, after the surface of the silicon wafer is made a surface having a fine uneven pattern, an aqueous cleaning liquid is applied to the surface, and the aqueous cleaning liquid is held in the recesses. Then, the aqueous cleaning liquid held in the recess is replaced with a cleaning liquid A different from the aqueous cleaning liquid. As a preferable example of the different cleaning liquid A, the water-repellent cleaning liquid specified in the present invention, water, an organic solvent, or a mixture thereof, or at least one of acid, alkali, and surfactant is mixed. And the like. In particular, in consideration of pattern damage and cleanliness, the water-repellent cleaning liquid specified in the present invention, water, an organic solvent, or a mixture thereof is particularly preferable. Further, when other than the water-repellent cleaning liquid is used as the different cleaning liquid A, it is preferable to replace the different cleaning liquid A with the water-repellent cleaning liquid while the different cleaning liquid A is held in the recess 4.

  Examples of the organic solvent which is one of preferred examples of the different cleaning liquid A include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, alcohols, and derivatives of polyhydric alcohols. And nitrogen-containing compound solvents.

  Examples of the hydrocarbons include toluene, benzene, xylene, hexane, heptane, and octane. Examples of the esters include ethyl acetate, propyl acetate, butyl acetate, and ethyl acetoacetate, and the ether. Examples of such classes include diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, dioxane and the like, and examples of the ketones include acetone, acetylacetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, cyclohexanone, isophorone, and the like. Examples of the halogen-containing solvent include perfluorocarbons such as perfluorooctane, perfluorononane, perfluorocyclopentane, perfluorocyclohexane, hexafluorobenzene, 1, 1, 1, Hydrofluorocarbons such as 3-pentafluorobutane, octafluorocyclopentane, 2,3-dihydrodecafluoropentane, Zeolora H (manufactured by Nippon Zeon), methyl perfluoroisobutyl ether, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, Hydrofluoroethers such as ethyl perfluoroisobutyl ether, Asahiklin AE-3000 (manufactured by Asahi Glass), Novec HFE-7100, Novec HFE-7200, Novec 7300, and Novec 7600 (all from 3M), chlorocarbons such as tetrachloromethane, chloroform Hydrochlorocarbons such as chlorofluorocarbons such as dichlorodifluoromethane, 1,1-dichloro-2,2,3,3,3-pe Tafluoropropane, 1,3-dichloro-1,1,2,2,3-pentafluoropropane, 1-chloro-3,3,3-trifluoropropene, 1,2-dichloro-3,3,3- There are hydrochlorofluorocarbons such as trifluoropropene, perfluoroethers, perfluoropolyethers, etc. Examples of the sulfoxide solvents include dimethyl sulfoxide, and examples of alcohols include methanol, ethanol, propanol, butanol. Ethylene glycol, 1,3-propanediol, etc. Examples of the derivative of the polyhydric alcohol include diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether. , Propylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, ethylene glycol diethyl Examples of nitrogen-containing compound solvents include formamide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, diethylamine, triethylamine, and pyridine. .

  FIG. 3 is a schematic view showing a state in which the recess 4 holds the cleaning liquid 8 in the cleaning process. The silicon wafer in the schematic diagram of FIG. 3 shows a part of the a-a ′ cross section of FIG. 1. In the cleaning process, a water-repellent cleaning liquid is supplied to the silicon wafer 1 on which the uneven pattern 2 is formed. At this time, as shown in FIG. 3, the water-repellent cleaning liquid is held in at least the concave portion 4, and the concave portion 4 is made water-repellent.

  When the water-repellent cleaning liquid is supplied from the state where the water-repellent cleaning liquid is once held in the recess 4 to a cleaning liquid different from the cleaning liquid, the water-repellent cleaning liquid held in the recess 4 is used as a cleaning liquid different from the water-repellent cleaning liquid. Replace with B. Examples of the different cleaning liquid B include an aqueous cleaning liquid composed of an aqueous solution, an organic solvent, a mixture of the aqueous cleaning liquid and an organic solvent, or a mixture of at least one of acid, alkali, and surfactant. In view of pattern damage and cleanliness, an aqueous cleaning liquid, an organic solvent, or a mixture of the aqueous cleaning liquid and an organic solvent is preferable. Further, when other than the aqueous cleaning liquid is used as the different cleaning liquid B, it is preferable to replace the cleaning liquid with the aqueous cleaning liquid in a state where the cleaning liquid other than the aqueous cleaning liquid is held in the recess 4.

  Examples of the organic solvent which is one of the preferable examples of the different cleaning liquid B include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, alcohols, and derivatives of polyhydric alcohols. And nitrogen-containing compound solvents.

  Examples of the hydrocarbons include toluene, benzene, xylene, hexane, heptane, and octane. Examples of the esters include ethyl acetate, propyl acetate, butyl acetate, and ethyl acetoacetate, and the ether. Examples of such classes include diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, dioxane and the like, and examples of the ketones include acetone, acetylacetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, cyclohexanone, isophorone, and the like. Examples of the halogen-containing solvent include perfluorocarbons such as perfluorooctane, perfluorononane, perfluorocyclopentane, perfluorocyclohexane, hexafluorobenzene, 1, 1, 1, Hydrofluorocarbons such as 3-pentafluorobutane, octafluorocyclopentane, 2,3-dihydrodecafluoropentane, Zeolora H (manufactured by Nippon Zeon), methyl perfluoroisobutyl ether, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, Hydrofluoroethers such as ethyl perfluoroisobutyl ether, Asahiklin AE-3000 (manufactured by Asahi Glass), Novec HFE-7100, Novec HFE-7200, Novec 7300, and Novec 7600 (all from 3M), chlorocarbons such as tetrachloromethane, chloroform Hydrochlorocarbons such as chlorofluorocarbons such as dichlorodifluoromethane, 1,1-dichloro-2,2,3,3,3-pe Tafluoropropane, 1,3-dichloro-1,1,2,2,3-pentafluoropropane, 1-chloro-3,3,3-trifluoropropene, 1,2-dichloro-3,3,3- There are hydrochlorofluorocarbons such as trifluoropropene, perfluoroethers, perfluoropolyethers, etc. Examples of the sulfoxide solvents include dimethyl sulfoxide, and examples of alcohols include methanol, ethanol, propanol, butanol. Ethylene glycol, 1,3-propanediol, etc. Examples of the derivative of the polyhydric alcohol include diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether. , Propylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, ethylene glycol diethyl Examples of nitrogen-containing compound solvents include formamide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, diethylamine, triethylamine, and pyridine. .

  Examples of the aqueous cleaning liquid include water or water mainly containing water mixed with at least one organic solvent, acid or alkali in water (for example, the water content is 50% by mass or more). It is done. In particular, in consideration of cleanliness, it is preferable to use water for the aqueous cleaning liquid.

  FIG. 4 shows a schematic diagram in the case where the aqueous cleaning liquid is held in the recess 4 made water repellent by the water repellent compound. The silicon wafer in the schematic diagram of FIG. 4 shows a part of the a-a ′ cross section of FIG. 1. The surface of the recess 4 has a surface state 10 that is water-repellent with a water-repellent compound. The surface state 10 that has been made water-repellent by the unit that can be chemically bonded to Si is held on the surface of the silicon wafer even when the aqueous cleaning liquid 9 is removed from the recess 4.

When the surface of the silicon wafer surface that has been made water-repellent by the water-repellent cleaning solution, that is, the surface of the recess 4 as shown in FIG. When it is assumed that the capillary force on the surface of the recess is 2.1 MN / m ² or less. It is preferable that the capillary force is 2.1 MN / m ² or less because pattern collapse hardly occurs. Also, when the capillary force is small, the collapse is further difficult to occur pattern, capillary force is particularly preferably 1.5Mn / ^{m 2} or less, more preferably 1.0 MN / ^{m 2} or less. Furthermore, it is ideal to adjust the contact angle with the cleaning liquid to around 90 ° so that the capillary force is as close to 0.0 MN / m ² as possible.

Moreover, in the water-repellent compound containing a reactive site capable of chemically bonding to Si of the water-repellent cleaning liquid and a hydrophobic group, the reactive site may react with a silanol group (Si-OH group). Examples thereof include halogen groups such as chloro group and bromo group, isocyanate group, amino group, dialkylamino group, isothiocyanate group, azide group, acetamide group, silazane, —N (CH ₃ ) COCH ₃ , —N. (CH ₃ ) COCF ₃ , Si—N bond such as imidazole ring, oxazolidinone ring, morpholine ring, alkoxy group, acetoxy group, trifluoroacetoxy group, —OC (CH ₃ ) ═CHCOCH ₃ , —OC (CH ₃ ) = _{N-Si (CH 3) 3} , -OC (CF 3) = N-Si (CH 3) 3, -CO-NH-Si (CH 3 Si-O-C bond such as _3, alkyl sulfonate group, Si-O-S bond such as perfluoroalkyl sulfonate group, or the like nitrile group. Examples of the hydrophobic group include a monovalent organic group containing a hydrocarbon group and a monovalent organic group containing a C—F bond. In such a water repellent compound, the reactive site reacts quickly with the silanol group of the silicon oxide layer of the concave-convex pattern of the silicon wafer, and the water repellent compound chemically bonds with Si of the silicon wafer through a siloxane bond. As a result, since the wafer surface can be covered with the hydrophobic group, the capillary force on the concave surface of the wafer can be reduced in a short time.

  Furthermore, in the water-repellent cleaning liquid, the water-repellent compound containing a reactive site capable of chemically bonding to Si of the silicon wafer and a hydrophobic group is at least one selected from the group consisting of the following general formulas [1] and [2]. Preferably it consists of one.

(R ¹ ) _a Si (CH ₃ ) _b H _c X _4-abc [1]
_{^{[R 2 Si (CH 3) 2}} -d H d ] _e NH _3-e [2]
Here, R ^{1 s} are each independently a monovalent organic group containing a hydrocarbon group having 1 to 18 carbon atoms or a monovalent organic group containing a fluoroalkyl chain having 1 to 8 carbon atoms. It is. R ² is each independently a monovalent organic group containing a hydrocarbon group having 1 to 18 carbon atoms or a monovalent organic group containing a fluoroalkyl chain having 1 to 8 carbon atoms. Further, X are each independently of one another, a halogen group, an alkoxy group, an acetoxy group, trifluoroacetoxy _{group, -OC (CH 3) = CHCOCH} 3, -OC (CH 3) = N-Si (CH 3) 3 _{, -OC (CF 3) = N} -Si (CH 3) 3, -CO-NH-Si (CH 3) 3, alkyl sulfonate group, perfluoroalkyl sulfonate group, a nitrile group, and, an element that binds to Si At least one group selected from the group consisting of monovalent organic groups of nitrogen is shown. a is an integer of 1 to 3, b and c are each an integer of 0 to 2, and the sum of a, b and c is 1 to 3. Furthermore, d is an integer of 0-2, and e is an integer of 1-3.

Also, ^{R 2} in ^{R 1,} and the general formula [2] of the general formula [1], _{respectively, C m H 2m + 1 (} m = 1~18), _{or, C n F 2n + 1 CH} 2 CH 2 ( It is particularly preferable that n = 1 to 8).

Examples of the water repellent compound represented by the general formula [1] include C ₁₈ H ₃₇ SiCl ₃ , C ₁₀ H ₂₁ SiCl ₃ , C ₆ H ₁₃ SiCl ₃ , C ₃ H ₇ SiCl ₃ , CH ₃ SiCl ₃ , C ₁₈ H ₃₇ Si (CH ₃ ) Cl ₂ , C ₁₀ H ₂₁ Si (CH ₃ ) Cl ₂ , C ₆ H ₁₃ Si (CH ₃ ) Cl ₂ , C ₃ H ₇ Si (CH ₃ ) Cl ₂ , (CH ₃ ) ₂ SiCl ₂ , C ₁₈ H ₃₇ Si (CH ₃ ) ₂ Cl, C ₁₀ H ₂₁ Si (CH ₃ ) ₂ Cl, C ₆ H ₁₃ Si (CH ₃ ) ₂ Cl, C ₃ H ₇ Si (CH _{3 ) 2 Cl, (CH 3)} 3 SiCl, (CH 3) alkyl chlorosilane such as 2 SiHCl, _{or,, C 8 F 17 CH 2} CH 2 SiCl 3, C 6 F 13 CH 2 CH _{SiCl 3, C 4 F 9 CH} 2 CH 2 SiCl 3, CF 3 CH 2 CH 2 SiCl 3, C 8 F 17 CH 2 CH 2 Si (CH 3) Cl 2, C 6 F 13 CH 2 CH 2 Si (CH _{3) Cl 2, C 4 F} 9 CH 2 CH 2 Si (CH 3) Cl 2, CF 3 CH 2 CH 2 Si (CH 3) Cl 2, C 8 F 17 CH 2 CH 2 Si (CH 3) 2 Cl _{, C 6 F 13 CH 2 CH} 2 Si (CH 3) 2 Cl, C 4 F 9 CH 2 CH 2 Si (CH 3) 2 Cl, CF 3 CH 2 CH 2 Si (CH 3) 2 Cl, CF 3 CH _{2 CH 2 Si (CH 3)} HCl fluoroalkyl chlorosilane or a chloro group of the chlorosilane, a halogen group other than a chloro group, such as bromo group, isocyanate group, a Kokishi group, acetoxy group, trifluoroacetoxy _{group, -OC (CH 3) = CHCOCH} 3, -OC (CH 3) = N-Si (CH 3) 3, -OC (CF 3) = N-Si (CH 3 ) ₃ , —CO—NH—Si (CH ₃ ) ₃ , alkyl sulfonate group, perfluoroalkyl sulfonate group, nitrile group, —NH ₂ , —N (CH ₃ ) ₂ , —N (C ₂ H ₅ ) ₂ , _{-NHCOCH 3, -N 3, -N =} C = S, -N (CH 3) COCH 3, -N (CH 3) COCF 3, -N = C (CH 3) OSi (CH 3) 3, -N _{= C (CF 3) OSi (} CH 3) 3, -NHCO-OSi (CH 3) 3, -NHCO-NH-Si (CH 3) 3, an imidazole ring, an oxazolidinone ring, a water-repellent compound by replacing the morpholine ring It can be used.

  Further, when there are a plurality of reactive sites of the water repellent compound, the water repellent compound is likely to aggregate, and it becomes difficult to obtain a homogeneous water-repellent surface state. As a result, in the step of irradiating the surface of the silicon wafer with light or heating the silicon wafer, additional light irradiation time or heating time for removing the site formed due to aggregation of the water repellent compound is required. Become. For this reason, it is more preferable that 4-abc indicating the number of reactive sites is 1.

Examples of the water repellent compound represented by the general formula [2] include (CH ₃ ) ₃ SiNHSi (CH ₃ ) ₃ , C ₂ H ₅ Si (CH ₃ ) ₂ NHSi (CH ₃ ) ₂ C ₂ H ₅ , _{C 3 H 7 Si (CH 3} ) 2 NHSi (CH 3) 2 C 3 H 7, C 6 H 13 Si (CH 3) 2 NHSi (CH 3) 2 C 6 H 13, C 6 H 5 Si (CH 3 ) ₂ NHSi (CH ₃ ) ₂ C ₆ H ₅ , {(CH ₃ ) ₃ Si} ₃ N, {C ₂ H ₅ Si (CH ₃ ) ₂ } ₃ N, (CH ₃ ) ₂ HSiNHSi (CH ₃ ) _{2 H, CF 3 CH 2 CH 2} Si (CH 3) 2 NHSi (CH 3) 2 CH 2 CH 2 CF 3, C 4 F 9 CH 2 CH 2 Si (CH 3) 2 NHSi (CH 3) 2 CH 2 CH ₂ C ₄ F ₉ , C _{6 F 13 CH 2 CH 2 Si (} CH 3) 2 NHSi (CH 3) 2 CH 2 CH 2 C 6 F 13, C 8 F 17 CH 2 CH 2 Si (CH 3) 2 NHSi (CH 3) 2 CH 2 CH ₂ C ₈ F ₁₇ , {CF ₃ CH ₂ CH ₂ Si (CH ₃ ) ₂ } ₃ N, or the like can be used. In particular, disilazane in which e in the general formula [2] is 2 is preferable.

  Among the water-repellent compounds exemplified above, chlorosilane, in which X is a chloro group in the general formula [1], is particularly preferable because the surface of the concave portion is easily made into a sufficiently water-repellent surface state in a short time.

  If water is present in the water-repellent cleaning solution, the reactive site of the water-repellent compound is hydrolyzed to become a silanol group (Si—OH). The reactive site also reacts with the silanol group, and as a result, the water-repellent compounds are bonded to form a dimer. Since this dimer has low reactivity with the silanol group of the silicon oxide layer of the silicon wafer, it takes a long time to make the surface of the silicon wafer water repellent. For this reason, as the solvent of the water-repellent cleaning liquid, an organic solvent other than water, that is, an organic solvent containing at least the alcohol solvent is used.

  Note that a trace amount of water may be present in the solvent of the water-repellent cleaning liquid. However, if this water is contained in a large amount in the solvent, the water repellent compound may be hydrolyzed by the water and the reactivity may be lowered. For this reason, the amount of water in the solvent is preferably low, and the amount of water is preferably less than 3 moles in terms of a molar ratio with respect to the water-repellent compound when mixed with the water-repellent compound. More preferably, the molar ratio is more preferably 1 mol times, and even more preferably less than 0.5 mol times.

  Further, a catalyst may be added to the water repellent cleaning liquid in order to promote the reaction between the water repellent compound and the wafer surface. Examples of such catalysts include trifluoroacetic acid, trifluoroacetic anhydride, pentafluoropropionic acid, pentafluoropropionic anhydride, trifluoromethanesulfonic acid, trifluoromethanesulfonic anhydride, sulfuric acid, hydrogen chloride-free acid, ammonia, and the like. , Bases such as alkylamine and dialkylamine, salts such as ammonium sulfide, potassium acetate and methylhydroxyamine hydrochloride, and metal complexes and metal salts such as tin, aluminum and titanium, and chlorosilane, trimethylsilyl trifluoroacetonate, Trimethylsilyl trifluoromethanesulfonate and the like are preferably used. In particular, considering catalytic effect and cleanliness, water-free acids such as trifluoroacetic acid, trifluoroacetic anhydride, trifluoromethanesulfonic acid, trifluoromethanesulfonic anhydride, sulfuric acid, hydrogen chloride, and chlorosilane, trimethylsilyl Trifluoroacetonate, trimethylsilyl trifluoromethanesulfonate and the like are preferable.

  The addition amount of the catalyst is preferably 0.001 to 5% by mass with respect to 100% by mass of the total amount of the water repellent compound. If the amount added is small, the catalytic effect is lowered, which is not preferable. Further, even if the amount is excessively increased, the catalytic effect is not improved, and conversely, there is a concern that the wafer surface may be eroded or remain as impurities on the wafer. For this reason, the catalyst addition amount is particularly preferably 0.005 to 3% by mass.

  Furthermore, when the temperature of the water-repellent cleaning liquid is increased, the surface of the recess is easily made water-repellent in a shorter time. It is preferable that the temperature at which the surface state easily becomes water-repellent is easily maintained at 0 to 160 ° C, particularly 10 to 120 ° C. The temperature of the water-repellent cleaning liquid is preferably maintained at the temperature even when held in the recess 4.

Next, a process of removing the cleaning liquid held in the recesses 4 made water-repellent by the water-repellent compound and further removing the cleaning agent is performed. The process
The step of removing the cleaning liquid held in the concave portion from the concave portion by drying The step of performing at least one treatment selected from irradiating the surface of the silicon wafer with light, heating the silicon wafer, and exposing the silicon wafer to ozone. It is preferable to have.

  When the cleaning liquid is removed from the recess, the cleaning liquid held in the recess is preferably an aqueous cleaning liquid. In this case, after the step of holding the water-repellent cleaning liquid in the recess, the water-based cleaning liquid made of an aqueous solution is placed in the recess through replacement of the water-repellent cleaning liquid held in the recess and the cleaning liquid B different from the water-repellent cleaning liquid. It is preferable to perform the holding step. When the cleaning liquid is removed from the recess, the cleaning liquid held in the recess may be a water-repellent cleaning liquid or the different cleaning liquid B.

  In the step of removing the cleaning liquid from the recess, the cleaning liquid is removed by drying. The drying is preferably performed by a known drying method such as spin drying, IPA (2-propanol) vapor drying, Marangoni drying, heat drying, hot air drying, or vacuum drying.

  In the process of performing at least one treatment selected from irradiating the silicon wafer surface with light, heating the silicon wafer, and exposing the silicon wafer to ozone, the water-repellent surface state 10 of the silicon wafer surface is Removed.

When removing the water-repellent surface state 10 by light irradiation, the Si—C bond, C—C bond, and C—F bond in the surface state 10 water-repellent by the water-repellent compound may be broken. For this purpose, ultraviolet rays including wavelengths shorter than 350 to 450 nm, 340 nm, and 240 nm, which are energies corresponding to their binding energies of 58 to 80 kcal / mol, 83 kcal / mol, and 116 kcal / mol, are irradiated. It is preferable to do. As this light source, a metal halide lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an excimer lamp, a carbon arc, or the like is used. The ultraviolet irradiation intensity is, for example, 100 mW / cm ² or more as measured by an illuminometer (irradiance intensity meter UM-10 manufactured by Konica Minolta Sensing, light receiving unit UM-360 [peak sensitivity wavelength: 365 nm, measurement wavelength range: 310 to 400 nm]). 200 mW / cm ² or more is particularly preferable, and if the irradiation intensity is less than 100 mW / cm ² , it takes a long time to remove the water-repellent surface state 10. If so, ultraviolet rays having a shorter wavelength are irradiated, so that even if the irradiation intensity is low, the water-repellent surface state 10 can be removed in a short time, which is preferable.

  Further, when removing the water-repellent surface state 10 by light irradiation, ozone is generated at the same time as the constituents of the water-repellent surface state 10 are decomposed by ultraviolet rays, and the water-repellent surface state 10 is generated by the ozone. Further, it is particularly preferable to oxidize and volatilize the constituent component of the surface state 10 because the processing time is shortened. As this light source, a low-pressure mercury lamp or an excimer lamp is used. Further, the silicon wafer may be heated while irradiating light.

  When the silicon wafer is heated, the silicon wafer is heated at 400 to 700 ° C, preferably 500 to 700 ° C. The heating time is preferably 1 to 60 minutes, preferably 10 to 30 minutes. In this step, ozone exposure, plasma irradiation, corona discharge, or the like may be used in combination. Further, light irradiation may be performed while heating the silicon wafer.

  When the silicon wafer is exposed to ozone, it is preferable that ozone generated by ultraviolet irradiation with a low-pressure mercury lamp or the like or low-temperature discharge with a high voltage is provided on the silicon wafer surface. The silicon wafer may be irradiated with light while being exposed to ozone, or may be heated.

  In the step of removing the water-repellent surface state 10 on the silicon wafer surface, the surface state 10 can be efficiently removed by combining the light irradiation treatment, the heat treatment, and the ozone exposure treatment. it can. In this step, plasma irradiation, corona discharge, or the like may be used in combination.

Making the surface of the silicon wafer a surface having a fine uneven pattern and replacing the cleaning liquid held in the recesses with other cleaning liquids are already established techniques as described in publicly known documents and the like. Therefore, in the present invention, the evaluation was mainly on the water-repellent cleaning liquid. In addition, the formula P = 2 × γ × cos θ / S (γ: surface tension, θ: contact angle, S: pattern dimension) described in the background art, etc.
As can be seen from the above, the pattern collapse greatly depends on the contact angle of the cleaning liquid to the silicon wafer surface, that is, the contact angle of the droplets and the surface tension of the cleaning liquid. In the case of the cleaning liquid held in the concave portion 4 of the concave / convex pattern 2, the contact angle of the liquid droplet and the capillary force on the concave portion surface, which can be considered as equivalent to the pattern collapse, are correlated. Capillary force may be derived from the evaluation of the contact angle of the surface state 10 droplet. In the examples, water, which is a typical aqueous cleaning solution, was used as the cleaning solution.

  However, in the case of a silicon wafer having a fine concavo-convex pattern on the surface, since the pattern is very fine, the water repellency of the water-repellent surface state 10 itself cannot be accurately evaluated.

  For the evaluation of the contact angle of water droplets for water repellency evaluation, as described in JIS R 3257 “Test method for wettability of substrate glass surface”, several μl of water droplets are dropped on the surface of the sample (base material). This is done by measuring the angle formed by the substrate surface. However, in the case of a silicon wafer having a pattern, the contact angle becomes very large. This is because a Wenzel effect and a Cassie effect occur, and the contact angle is affected by the surface shape (roughness) of the substrate, and the apparent contact angle of water droplets increases.

  Therefore, in the present invention, the water-repellent cleaning solution is applied to a silicon wafer having a smooth surface, and the water-repellent surface state is converted into a water-repellent surface state. The surface state 10 was regarded as being evaluated.

  Details are described below. In the following, the evaluation method of a silicon wafer provided with a water-repellent cleaning liquid, the preparation of the water-repellent cleaning liquid, and the evaluation results after supplying the water-repellent cleaning liquid to the silicon wafer will be described.

[Method for evaluating silicon wafer provided with water-repellent cleaning liquid]
The following evaluations (1) to (4) were performed as evaluation methods for a silicon wafer provided with a water-repellent cleaning liquid.

(1) Contact angle evaluation of the surface state made water-repellent with a water-repellent cleaning solution Place approximately 2 μl of pure water on the water-repellent wafer surface, and measure the angle (contact angle) between the water droplet and the wafer surface. (Measured by Kyowa Interface Science: CA-X type). Here, the contact angle of the water-repellent surface state in the range of 50 to 120 ° was regarded as acceptable (denoted as “◯” in the table).

(2) Evaluation of capillary force P was calculated using the following equation, and the capillary force (absolute value of P) was determined.

P = 2 × γ × cos θ / S
Here, γ is the surface tension, θ is the contact angle, and S is the pattern dimension. In the pattern with a line width of 45 nm and an aspect ratio of 6, the pattern tends to collapse when the cleaning liquid is water when the wafer passes through the gas-liquid interface, and the pattern does not easily collapse when 2-propanol. When the pattern size is 45 nm and the wafer surface is silicon oxide, the capillary force is 0.98 MN / m ² when the cleaning liquid is 2-propanol (surface tension: 22 mN / m, contact angle with silicon oxide: 1 °). On the other hand, the capillary force is 3.2 MN / m ^{2 in} water (surface tension: 72 mN / m, contact angle with silicon oxide: 2.5 °) having the largest surface tension among liquids excluding mercury. Therefore, the intermediate 2.1MN / ^{m 2} as the target, the capillary force when the water was retained was evaluated as acceptable if the following 2.1MN / ^{m 2} (expressed as ○ in Table).

(3) Removability of surface state made water repellent by water-repellent cleaning liquid The sample was irradiated with UV light from a metal halide lamp for 2 hours under the following conditions. A sample having a water droplet contact angle of 30 ° or less after irradiation was regarded as acceptable (denoted as “◯” in the table).

-Lamp: M0155-L312 (strength: 1.5 kW) manufactured by Eye Graphics
Illuminance: The measured value under the following conditions is 128 mW / cm ²
Measuring device: UV intensity meter (Konica Minolta Sensing, UM-10)
-Light receiving part: UM-360
(Receiving wavelength: 310 to 400 nm, peak wavelength: 365 nm)
・ Measurement mode: Irradiance measurement

(4) Evaluation of surface smoothness of silicon wafer after removal of water-repellent surface state The surface was observed with an atomic force electron microscope (Seiko-Electronics: SPI3700, 2.5 μm square scan), and the centerline average surface roughness was Sa: Ra (nm) was determined. Ra is a three-dimensional extension of the centerline average roughness defined in JIS B 0601 to the measurement surface. “The absolute value of the deviation from the reference surface to the specified surface is averaged. The value was calculated by the following formula. If the Ra value of the wafer after removing the water-repellent surface state is 1 nm or less, the wafer surface is not eroded by cleaning, and the residue of the water-repellent cleaning liquid is not present on the wafer surface. (Indicated by ○).

ここで、Ｘ_Ｌ、Ｘ_Ｒ、Ｙ_Ｂ、Ｙ_Ｔは、それぞれ、Ｘ座標、Ｙ座標の測定範囲を示す。Ｓ_０は、測定面が理想的にフラットであるとした時の面積であり、（Ｘ_Ｒ−Ｘ_Ｌ）×（Ｙ_Ｂ−Ｙ_Ｔ）の値とした。また、Ｆ（Ｘ，Ｙ）は、測定点（Ｘ，Ｙ）における高さ、Ｚ_０は、測定面内の平均高さを表す。

Here, X _L , X _R , Y _B , and Y _T indicate measurement ranges of the X coordinate and the Y coordinate, respectively. S ₀ is an area when the measurement surface is ideally flat, and is a value of (X _R −X _L ) × (Y _B −Y _T ). Moreover, F (X, Y) is, the measurement point (X, Y) in height, _{Z 0} represents the average height within the measurement surface.

[Example 1]
(1) Preparation of water-repellent cleaning solution Trimethylchlorosilane [(CH ₃ ) ₃ SiCl] as water-repellent compound; 3 g, 2-propanol (iPA) as alcohol solvent; 5 g and toluene as an organic solvent other than alcohol solvent; 92 g The solvent was mixed and stirred for about 5 minutes. The concentration of the water-repellent compound relative to the total amount of the water-repellent cleaning liquid (hereinafter referred to as “water-repellent compound concentration”) was 3% by mass, and the concentration of the alcohol solvent relative to the total amount of the water-repellent cleaning liquid ( Hereinafter, a water-repellent cleaning liquid having an alcohol concentration of 5% by mass was obtained.

(2) Cleaning of silicon wafer A silicon wafer with a smooth thermal oxide film (Si wafer having a thermal oxide film layer with a thickness of 1 μm on the surface) is immersed in a 1% by mass hydrofluoric acid aqueous solution for 2 min, and then 1 min in pure water. It was immersed in acetone for 1 min.

(3) Surface treatment with water-repellent cleaning liquid on silicon wafer surface The silicon wafer was immersed in the water-repellent cleaning liquid prepared in “(1) Preparation of water-repellent cleaning liquid” at 20 ° C. for 10 minutes. Thereafter, the silicon wafer was immersed in iPA for 1 min, and then immersed in pure water as an aqueous cleaning solution for 1 min. Finally, the silicon wafer was taken out from the pure water and air was blown to remove the pure water on the surface.

When the obtained wafer was evaluated in the manner described in the above-mentioned “Method for evaluating silicon wafer provided with water-repellent cleaning solution”, as shown in Table 1, the initial contact angle before the surface treatment was less than 10 °. However, the contact angle after the surface treatment was 70 °, which showed the effect of imparting water repellency. Further, when the capillary force when water was held was calculated using the formula described in the above “Evaluation of Capillary Force”, the capillary force was 1.1 MN / m ² and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 2]
All were the same as Example 1 except that the water repellent compound concentration was 1% by mass. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 66 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.3 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 3]
All were the same as in Example 1 except that the alcohol concentration was 10% by mass. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 68 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.2 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 4]
All were the same as in Example 1 except that 1-propanol (nPA) was used as the alcohol solvent. As shown in Table 1, the evaluation results showed that the contact angle after the surface treatment was 70 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.1 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 5]
All were the same as Example 1 except that ethanol was used as the alcohol solvent. As shown in Table 1, the evaluation results showed that the contact angle after the surface treatment was 70 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.1 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 6]
All were the same as Example 1 except that 1-butanol was used as the alcohol solvent. As shown in Table 1, the evaluation results showed that the contact angle after the surface treatment was 70 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.1 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 7]
All were the same as Example 1 except that 1-hexanol was used as the alcohol solvent. As shown in Table 1, the evaluation results showed that the contact angle after the surface treatment was 70 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.1 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 8]
The same procedure as in Example 1 was conducted except that a fluorine-based solvent (Asahiclin AE3000: Hydrofluoroether manufactured by Asahi Glass) was used as the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 9]
The organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was the same as Example 1 except that a fluorinated solvent (Novec HFE-7100 manufactured by Sumitomo 3M) was used. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 76 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.8 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 10]
All were the same as in Example 1 except that 1-chloro-3,3,3-trifluoropropene (CTFP) was used as the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 11]
The same procedure as in Example 1 was performed except that 1,2-dichloro-3,3,3-trifluoropropene (DCTFP) was used as the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 12]
The same procedure as in Example 1 was conducted except that trifluoropropyldimethylchlorosilane [CF ₃ CH ₂ CH ₂ Si (CH ₃ ) ₂ Cl] was used as the water repellent compound. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 66 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.3 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 13]
The same procedure as in Example 1 was conducted except that nonafluorohexyldimethylchlorosilane [CF ₃ (CF ₂ ) ₃ CH ₂ CH ₂ Si (CH ₃ ) ₂ Cl] was used as the water repellent compound. As shown in Table 1, the evaluation results showed that the contact angle after the surface treatment was 70 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.1 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 14]
The same procedure as in Example 1 was performed except that the silicon wafer was immersed in a hydrofluoric acid aqueous solution for 2 minutes in the above “(2) Cleaning of silicon wafer”, then immersed in pure water for 1 min and iPA for 1 min. As shown in Table 1, the evaluation results showed that the contact angle after the surface treatment was 70 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.1 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 15]
All were the same as Example 14 except that the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was changed to HFE-7100. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 74 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.9 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 16]
All were the same as Example 14 except that the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was CTFP. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 17]
All were the same as Example 15 except that 1-propanol (nPA) was used as the alcohol solvent. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 80 °, which showed the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.6 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 18]
All were the same as Example 17 except that the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was CTFP. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 78 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.7 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 19]
All were the same as Example 17 except that the water-repellent compound concentration was 5 mass%. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 82 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.4 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 20]
All were the same as Example 17 except that the water-repellent compound concentration was 10 mass%. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 82 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.4 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 21]
All were the same as Example 17 except that the water-repellent compound concentration was 50 mass%. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 84 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.3 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 22]
All were the same as Example 19 except that the organic solvent in the water-repellent cleaning liquid was 1-propanol (nPA). As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 74 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.9 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 23]
All were the same as Example 22 except that the water-repellent compound concentration was 10 mass%. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 78 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.7 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 24]
All were the same as Example 22 except that the water-repellent compound concentration was 50 mass%. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 80 °, which showed the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.6 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 25]
After immersing the silicon wafer in the water-repellent cleaning liquid in “(3) Surface treatment with water-repellent cleaning liquid on the surface of the silicon wafer” described above, the silicon wafer is immersed in pure water for 1 minute, and finally the silicon wafer is taken out from the pure water and blown with air. All were the same as Example 15 except that a water-repellent surface state wafer was obtained. As shown in Table 1, the evaluation result showed that the contact angle after the surface treatment was 74 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.9 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 26]
All were the same as in Example 25 except that the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was CTFP. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 27]
All were the same as Example 25 except that the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was changed to DCTFP. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 28]
After immersing the silicon wafer in the water-repellent cleaning liquid in “(3) Surface treatment of the silicon wafer surface with the water-repellent cleaning liquid”, air was blown to remove the water-repellent cleaning liquid on the surface. Next, the wafer is dipped in iPA for 1 min, dipped in pure water for 1 min. Finally, the silicon wafer is taken out from the pure water, and air is blown to remove the pure water on the surface, whereby a water-repellent surface state wafer is obtained. All were the same as Example 15 except that they were obtained. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 74 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.9 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 29]
After immersing the silicon wafer in the water-repellent cleaning liquid in “(3) Surface treatment of the silicon wafer surface with the water-repellent cleaning liquid”, air was blown to remove the water-repellent cleaning liquid on the surface. Next, all of the examples except for obtaining a water-repellent surface state wafer by immersing in iPA for 1 min and finally removing the silicon wafer from iPA and blowing air to remove the surface iPA. Same as above. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 30]
All were the same as in Example 29 except that CTFP was used as the organic solvent other than the alcohol solvent in the water-repellent cleaning solution. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 31]
After immersing the silicon wafer in the water-repellent cleaning liquid in “(3) Surface treatment of the silicon wafer surface with the water-repellent cleaning liquid”, air was blown to remove the water-repellent cleaning liquid on the surface. Next, all steps were carried out except that the wafer was dipped in pure water for 1 min, and finally the silicon wafer was taken out from the pure water and air was blown to remove the pure water on the surface to obtain a water-repellent surface state wafer. Same as Example 15. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 74 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.9 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 32]
All were the same as Example 31 except that the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was CTFP. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 33]
All the steps were performed except that after removing the silicon wafer from the water-repellent cleaning solution in “(3) Surface treatment with water-repellent cleaning solution on the surface of the silicon wafer”, air was blown to obtain a wafer having a water-repellent surface state. Same as Example 15. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 74 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.9 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 34]
All were the same as Example 33 except that the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was CTFP. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 35]
The same procedure as in Example 33 was performed except that DCTFP was used as the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 36]
After immersing the silicon wafer in the water-repellent cleaning liquid in “(3) Surface treatment with water-repellent cleaning liquid on the surface of the silicon wafer” described above, the silicon wafer is immersed in iPA for 1 min. Finally, the silicon wafer is taken out from the iPA and blown with air. The same procedure as in Example 15 was performed except that a wafer having a water-repellent surface state was obtained by removing iPA. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 74 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.9 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 37]
All were the same as Example 36 except that the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was CTFP. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 38]
All were the same as Example 36 except that the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was changed to DCTFP. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 39]
The same as Example 1 except that the silicon wafer was immersed in a hydrofluoric acid aqueous solution for 2 min in the above “(2) Cleaning of silicon wafer”, then immersed in pure water for 1 min, immersed in iPA for 1 min, and immersed in toluene for 1 min. did. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 70 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.1 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 40]
Example 15 is the same as Example 15 except that the silicon wafer was immersed in a hydrofluoric acid aqueous solution for 2 min in the “(2) Cleaning of silicon wafer”, then immersed in pure water for 1 min, immersed in iPA for 1 min, and immersed in HFE-7100 for 1 min. Same as above. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 74 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.9 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 41]
The same procedure as in Example 15 was performed except that the silicon wafer was immersed in an aqueous hydrofluoric acid solution for 2 minutes and then immersed in pure water for 1 minute in “(2) Cleaning of silicon wafer”. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 74 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.9 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 42]
All were the same as Example 41 except that the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid was CTFP. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 43]
The same procedure as in Example 41 was performed except that DCTFP was used as the organic solvent other than the alcohol solvent in the water-repellent cleaning liquid. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 72 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 1.0 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 44]
All were the same as Example 15 except that ethyldimethylchlorosilane [C ₂ H ₅ Si (CH ₃ ) ₂ Cl] was used as the water repellent compound. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 78 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.7 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Example 45]
All were the same as Example 15 except that propyldimethylchlorosilane [C ₃ H ₇ Si (CH ₃ ) ₂ Cl] was used as the water repellent compound. As shown in Table 2, the evaluation result showed that the contact angle after the surface treatment was 82 °, indicating the effect of imparting water repellency. Moreover, the capillary force when water was held was 0.5 MN / m ² , and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the water-repellent surface state could be removed. Furthermore, the Ra value of the wafer after UV irradiation was less than 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no residue of the water-repellent cleaning liquid remained after UV irradiation.

[Comparative Example 1]
Example 1 was the same as Example 1 except that the water-repellent cleaning solution was not applied to the silicon wafer. That is, in this comparative example, a wafer having a surface state that is not water-repellent was evaluated. As shown in Table 2, the contact angle of the wafer was as low as 3 °, and the capillary force when water was retained was as large as 3.2 MN / m ² .

[Comparative Example 2]
3.0 g, iPA; 94.6 g were mixed, and then 0.1N nitric acid aqueous solution (pH 1); 2.4 g was added and stirred at room temperature for about 24 hours to obtain a water-repellent cleaning solution. The same as Example 1 except for the above. That is, in this comparative example, a water-repellent cleaning liquid containing a water-repellent compound whose reactive site was hydrolyzed was used. As shown in Table 2, the contact angle after the surface treatment was as low as 14 °, and the capillary force when water was retained was as large as 3.1 MN / m ² as shown in Table 2.

DESCRIPTION OF SYMBOLS 1 Silicon wafer 2 Fine uneven | corrugated pattern on the surface of a silicon wafer 3 Pattern convex part 4 Pattern concave part 5 Concave width 6 Convex part height 7 Convex part width 8 Cleaning liquid 9 held in the concave part 4 Aqueous cleaning solution 10 Surface condition made water repellent by water repellent compound

Claims (8)

A silicon wafer cleaning agent having a fine concavo-convex pattern on the surface, the silicon wafer cleaning agent comprising at least an aqueous cleaning liquid and a water-repellent cleaning liquid for repelling at least concave portions of the concavo-convex pattern during the cleaning process. The water-repellent cleaning liquid is characterized by containing a mixture of a water-repellent compound containing a reactive site capable of chemically bonding to Si of a silicon wafer and a hydrophobic group, and an organic solvent containing at least an alcohol solvent. Cleaning agent for silicon wafers. 2. The cleaning agent for a silicon wafer according to claim 1, wherein the alcohol solvent is at least one selected from the group consisting of alcohols having 10 or less carbon atoms. The said water-repellent compound consists of at least one chosen from the group which consists of following General formula [1] and [2], The cleaning agent for silicon wafers of Claim 1 or Claim 2 characterized by the above-mentioned.
(R ¹ ) _a Si (CH ₃ ) _b H _c X _4-abc [1]
_{^{[R 2 Si (CH 3) 2}} -d H d ] _e NH _3-e [2]
Here, R ^{1 s} are each independently a monovalent organic group containing a hydrocarbon group having 1 to 18 carbon atoms or a monovalent organic group containing a fluoroalkyl chain having 1 to 8 carbon atoms. Represents. R ^{2 s} each independently represent a monovalent organic group containing a hydrocarbon group having 1 to 18 carbon atoms or a monovalent organic group containing a fluoroalkyl chain having 1 to 8 carbon atoms. Further, X are each independently of one another, a halogen group, an alkoxy group, an acetoxy group, trifluoroacetoxy _{group, -OC (CH 3) = CHCOCH} 3, -OC (CH 3) = N-Si (CH 3) 3 _{, -OC (CF 3) = N} -Si (CH 3) 3, -CO-NH-Si (CH 3) 3, alkyl sulfonate group, perfluoroalkyl sulfonate group, a nitrile group, and, an element that binds to Si It represents at least one group selected from the group consisting of monovalent organic groups of nitrogen. a is an integer of 1 to 3, b and c are each an integer of 0 to 2, and the sum of a, b and c is 1 to 3. Furthermore, d is an integer of 0 to 2, and e is an integer of 1 to 3. The said organic solvent is the said alcohol solvent and an aprotic solvent, The cleaning agent for silicon wafers in any one of the Claims 1 thru | or 3 characterized by the above-mentioned. The said organic solvent is the said alcohol solvent and a nonflammable halogen-containing solvent, The cleaning agent for silicon wafers in any one of the Claims 1 thru | or 4 characterized by the above-mentioned. The capillary force on the surface of the recess is assumed to be 2.1 MN / m ² or less when it is assumed that water is held in the recess on the surface of the silicon wafer that has been made water-repellent by the water-repellent cleaning liquid. The cleaning agent for silicon wafers according to any one of claims 1 to 5. This is a water-repellent cleaning liquid for repelling at least the recesses of the concavo-convex pattern during the cleaning process of the silicon wafer having a fine concavo-convex pattern on the surface, and the water-repellent cleaning liquid can be chemically bonded to Si of the silicon wafer. A water-repellent cleaning liquid used during a silicon wafer cleaning process, comprising a mixture of a water-repellent compound containing a reactive site and a hydrophobic group and an organic solvent containing at least an alcohol solvent. A silicon wafer surface cleaning method using the silicon wafer cleaning agent according to any one of claims 1 to 6, wherein the method includes irradiating the silicon wafer surface with light after removing the cleaning liquid from the silicon wafer surface. A method for cleaning the surface of a silicon wafer, comprising the steps of performing at least one treatment selected from heating a silicon wafer and exposing the silicon wafer to ozone.

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