JP2012178432A - Water-repellent protective film forming solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-repellent protective film forming solution that contains a water-repellent protective film forming agent for forming a water-repellent protective film on at least one recessed surface of a wafer to clean the metal wafer.SOLUTION: A wafer has surfaces with an uneven pattern formed thereon, and at least one portion of recessed surfaces of the uneven pattern include at least one kind of substance selected from a group consisting of titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium. A water-repellent protective film forming solution contains a water-repellent protective film forming agent for forming a water-repellent protective film on the recessed surfaces of the wafer (metal wafer). Also provided is a method for cleaning the wafer for forming the protective film on the recessed surface using the solution to reduce interaction between liquid retained in the recess and the recessed surface, thereby improving cleaning process that tends to induce a pattern collapse.

Description

  The present invention relates to a substrate (wafer) cleaning technique in manufacturing a semiconductor device or the like.

  In the production of semiconductor chips, a fine uneven pattern is formed on the silicon wafer surface through film formation, lithography, etching, etc., and then water (pure water) or an organic solvent is used to clean the wafer surface. Is washed. Since elements are in the direction of miniaturization in order to increase the degree of integration, the interval between the concave and convex patterns is becoming increasingly narrow. For this reason, when washing with water (pure water) and drying the water from the wafer surface, the problem that the concave-convex pattern collapses due to capillary action when the gas-liquid interface passes through the pattern is becoming more likely to occur. . This problem becomes more prominent in semiconductor chips having a line width (recessed portion width) of the order of 20 nm or 10 nm, particularly in the case of a wafer with a pattern of line and space, for example, in which the pattern spacing of the unevenness becomes narrower. ing.

  Patent Document 1 discloses a technique for replacing a cleaning liquid from water to 2-propanol before passing through a gas-liquid interface as a technique for suppressing pattern collapse. However, it is said that there is a limit such that the aspect ratio of the pattern that can be handled is 5 or less.

  Further, Patent Document 2 discloses a technique for a resist pattern as a technique for suppressing pattern collapse. This technique is a technique for suppressing pattern collapse by reducing the capillary force to the limit. However, the disclosed technique is intended for a resist pattern, and modifies the resist itself, and is not applicable to this application. Furthermore, since it can be finally removed together with the resist, it is not necessary to assume a method for removing the treatment agent after drying, and it cannot be applied to this purpose.

  In Patent Document 3, a water-repellent protective film is formed on a wafer surface on which a concavo-convex pattern of a silicon-based material is formed using a water-soluble surfactant or a silane coupling agent to reduce capillary force, A cleaning method for preventing the collapse of the battery is disclosed.

  Patent Documents 4 and 5 disclose techniques for preventing pattern collapse by performing a hydrophobic treatment using a treatment liquid containing a silylating agent such as N, N-dimethylaminotrimethylsilane and a solvent. ing.

JP 2008-198958 A Japanese Patent Laid-Open No. 5-299336 Patent No. 4403202 JP2010-129932A International Publication No. 10/47196 Pamphlet

  The present invention relates to a technique for cleaning a substrate (wafer) for the purpose of improving the manufacturing yield of a device having a circuit pattern that is fine and having a high aspect ratio, particularly in the manufacture of semiconductor devices. The present invention relates to a water-repellent chemical solution and the like intended to improve a cleaning process that easily induces a collapse of a concavo-convex pattern of a wafer having a surface. Until now, a wafer having a silicon element on the surface has been generally used as the wafer. However, with the diversification of patterns, titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium are used. Wafers having at least one substance selected from the group on the surface have begun to be used. In order to prevent pattern collapse by making the surface of the concavo-convex pattern water repellent, in order to form a water-repellent protective film on the surface of the concavo-convex pattern, reaction activity such as hydroxyl groups present on the surface of the concavo-convex pattern or the wafer surface It is necessary to bond the point and the compound forming the protective film. The concavo-convex pattern differs in the amount of hydroxyl groups per unit area because the amount of the original hydroxyl groups differs depending on the type of material, and the ease of formation of hydroxyl groups varies depending on the surface treatment conditions such as water. There is. Furthermore, the reactivity of the hydroxyl group varies depending on the atom to which the hydroxyl group, which is the reactive site, binds. In the case of a wafer including a substance that hardly forms a hydroxyl group on the surface or a substance that has a low reactivity of a hydroxyl group existing on the surface, such as the substance, in at least a part of the concave surface of the concave / convex pattern, Patent Documents 3 to 5 describe. Any of these treatment liquids and treatment methods cannot be used to form a water repellent protective film that prevents the pattern from collapsing.

  The present invention provides a wafer having a concavo-convex pattern formed on the surface, wherein at least a part of the concavo-convex pattern is selected from the group consisting of titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium. In some cases, a water-repellent protective film (hereinafter simply referred to as “protective film”) is formed on the concave surface of a wafer (hereinafter, sometimes referred to as “metal wafer” or simply “wafer”) containing at least one kind of substance. A water-repellent protective film forming agent (hereinafter simply referred to as “protective film-forming agent”) that forms a water-repellent protective film-forming chemical solution (hereinafter referred to as “protective film-forming chemical solution”) or simply “chemical solution”. And a protective film is formed on the surface of the recess using the chemical solution, and the liquid held in the recess and the surface of the recess By capable of reducing the interaction, and to provide a method of cleaning the wafer to improve the induced easy cleaning step pattern collapse.

  Pattern collapse occurs when the gas-liquid interface passes through the pattern when the wafer is dried. 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
(Wherein γ is the surface tension of the liquid held in the recess, θ is the contact angle between the recess surface and the liquid held in the recess, and S is the width of the recess.)

  In the present invention, in order to overcome the above-described problems, attention was paid to the material of the water-repellent protective film formed on the surface of the concavo-convex pattern. That is, the present invention relates to a material having a concavo-convex pattern formed of a substance that hardly forms a hydroxyl group on the surface, such as titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, or ruthenium, or a substance that has a low hydroxyl reactivity on the surface. Even a wafer included in at least a part of the concave surface effectively imparts water repellency to the concave surface.

  The present inventors have intensively studied, and by using a water-repellent protective film forming chemical containing a silicon compound having a hydrophobic group having a strong hydrophobicity as a protective film forming agent, it is difficult to depend on the material of the uneven pattern surface of the wafer. It has been found that a protective film capable of producing good water repellency can be formed and cleaning can be performed efficiently.

  The hydrophobic group in the present invention refers to an unsubstituted hydrocarbon group or a hydrocarbon group in which a part of the hydrogen element in the hydrocarbon group is substituted with a halogen element. The hydrophobicity of the hydrophobic group increases as the number of carbon atoms in the hydrocarbon group increases. Furthermore, in the case of a hydrocarbon group in which a part of the hydrogen element in the hydrocarbon group is substituted with a halogen element, the hydrophobicity of the hydrophobic group may increase. In particular, if the halogen element to be substituted is a fluorine element, the hydrophobicity of the hydrophobic group becomes stronger. The greater the number of fluorine elements to be substituted, the stronger the hydrophobicity of the hydrophobic group.

The present invention provides a wafer having a concavo-convex pattern formed on the surface, wherein at least a part of the concave surface of the concavo-convex pattern is selected from the group consisting of titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium. A water-repellent protective film-forming chemical solution containing a water-repellent protective film-forming agent for forming a water-repellent protective film on at least the concave surface of the wafer in the cleaning of a wafer containing one kind of substance, A water repellent protective film forming chemical, wherein the forming agent is a silicon compound represented by the following general formula [1].
R ¹ _a R ² _b SiX _4-a-b [1]
[In the formula [1], R ¹ are each independently a hydrocarbon group in which at least one hydrogen element having 1 to 18 carbon atoms is substituted with a fluorine element, and R ² are each independently , A hydrogen group, or a hydrocarbon group having 1 to 18 carbon atoms, the total number of carbon atoms contained in R ¹ and R ² in the formula [1] is 6 or more, and X is independently of each other. And at least one group selected from the group consisting of a monovalent functional group in which the element bonded to the silicon element is nitrogen, a monovalent functional group in which the element bonded to the silicon element is oxygen, and a halogen group. . Moreover, a is an integer of 1-3, b is an integer of 0-2, and the sum total of a and b is 1-3. ]

The water repellent protective film forming agent is preferably a silicon compound represented by the following general formula [2].
R ¹ _a R ² _b SiX [2]
[In the formula [2], R ¹ are each independently a hydrocarbon group in which at least one hydrogen element having 1 to 18 carbon atoms is substituted with a fluorine element, and R ² are each independently , A hydrogen group, or a hydrocarbon group having 1 to 18 carbon atoms, the total number of carbon atoms contained in R ¹ and R ² in the formula [2] is 6 or more, and X is bonded to a silicon element. A monovalent functional group in which the element to be bonded is nitrogen, a monovalent functional group in which the element bonded to the silicon element is oxygen, or a halogen group. A is an integer of 1 to 3, b is an integer of 0 to 2, and the sum of a and b is 3. ]

In addition, the water repellent protective film forming agent is preferably a silicon compound represented by the following general formula [3].
R ³ (CH ₃ ) ₂ SiX [3]
[In the formula [3], R ³ is a hydrocarbon group in which at least one hydrogen element having 4 to 18 carbon atoms is substituted with a fluorine element, and X is a monovalent element in which the element bonded to the silicon element is nitrogen. A monovalent functional group in which the element bonded to the silicon element is oxygen, or a halogen group. ]

Moreover, it is preferable that R < ¹ > or R < ³ > in the said silicon compound contains a 5 or more fluorine atom. Since the hydrocarbon group in which five or more hydrogen elements are substituted with a fluorine element as described above is a group having particularly excellent hydrophobicity, as a result, excellent water repellency can be imparted to the resulting protective film.

  Moreover, it is preferable that the said water repellent protective film forming chemical | medical solution contains a solvent.

  Moreover, it is preferable that the said water repellent protective film forming chemical | medical solution contains an acid.

  Moreover, it is preferable that the said water-repellent protective film forming agent is mixed so that it may become 0.1-50 mass% with respect to 100 mass% of total amounts of the said water-repellent protective film forming chemical | medical solution.

Further, in the present invention, at least a part of the concave surface of the concavo-convex pattern is selected from the group consisting of titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium. Cleaning a wafer containing one substance,
A water-based cleaning liquid cleaning step for cleaning the wafer surface with a water-based cleaning liquid. A water-repellent protective film-forming chemical solution containing a water-repellent protective film-forming agent for forming a water-repellent protective film on the wafer surface is formed in at least a recess of the wafer. Holding and forming a water-repellent protective film on the surface of the recess, forming a water-repellent protective film, removing the liquid on the wafer surface, removing the water-repellent protective film, removing the water-repellent protective film from the surface of the recess And a method for cleaning a wafer, wherein the water repellent protective film forming chemical solution is used in the water repellent protective film forming step.

  In the water repellent protective film removing step, the water repellent protective film is selected from the group consisting of irradiating the wafer surface with light, heating the wafer, exposing the wafer to ozone, and irradiating the wafer with plasma. The cleaning method is preferably performed by at least one treatment method.

  In the present invention, the water-repellent protective film is a film that is formed on the wafer surface to lower the wettability of the wafer surface, that is, a film that imparts water repellency. In the present invention, the water repellency means that the surface energy of the article surface is reduced and the interaction (for example, hydrogen bond, intermolecular force) between water or other liquid and the article surface is reduced. It is. 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.

  By using the chemical solution of the present invention, at least a part of the concave surface of the concavo-convex pattern is made of titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium in the wafer having the concavo-convex pattern formed on the surface. In the process of cleaning a wafer containing at least one substance selected from the group, the capillary force acting on the concavo-convex pattern is reduced, and the pattern collapse preventing effect is exhibited. When this cleaning method is used, the cleaning step in the method for manufacturing a wafer having a concavo-convex pattern on the surface can be improved without lowering the throughput. Therefore, the cleaning method of the present invention and the method of manufacturing a wafer having a concavo-convex pattern on the surface performed using a chemical solution are highly productive. In addition, since it is possible to cope with the cleaning of various types of wafers having different surface materials, it is possible to reduce the change of the cleaning condition according to the type of the wafer.

It is a figure which shows a schematic diagram when the wafer 1 by which the surface was made into the surface which has the uneven | corrugated pattern 2 is seen. FIG. 2 shows a part of the a-a ′ cross section in FIG. 1. The recessed part 4 has shown the schematic diagram of the state holding the protective film formation chemical | medical solution 8. FIG. It is a figure which shows the schematic diagram of the state by which the liquid was hold | maintained at the recessed part 4 in which the protective film was formed.

Hereinafter, the present invention will be described in more detail. The water-repellent protective film-forming chemical solution of the present invention comprises a wafer having a concavo-convex pattern formed on a surface thereof, wherein at least a part of the concavo-convex pattern has titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium In cleaning a wafer containing at least one substance selected from the group consisting of: a water repellent protective film forming chemical solution containing a water repellent protective film forming agent for forming a water repellent protective film on at least the concave surface of the wafer. And the water repellent protective film forming agent is a silicon compound represented by the following general formula [1].
R ¹ _a R ² _b SiX _4-a-b [1]
[In the formula [1], R ¹ are each independently a hydrocarbon group in which at least one hydrogen element having 1 to 18 carbon atoms is substituted with a fluorine element, and R ² are each independently , A hydrogen group, or a hydrocarbon group having 1 to 18 carbon atoms, the total number of carbon atoms contained in R ¹ and R ² in the formula [1] is 6 or more, and X is independently of each other. And at least one group selected from the group consisting of a monovalent functional group in which the element bonded to the silicon element is nitrogen, a monovalent functional group in which the element bonded to the silicon element is oxygen, and a halogen group. . Moreover, a is an integer of 1-3, b is an integer of 0-2, and the sum total of a and b is 1-3. ]

For example, a silicon surface or a silicon oxide surface is rich in hydroxyl groups (silanol groups) that are reactive sites, but in general, titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium. Hydroxyl groups are difficult to form on the surface, and the reactivity of existing hydroxyl groups is low. It is difficult to impart sufficient water repellency to the surface even if a conventional silane coupling agent is reacted with such a small amount or low reactivity of a hydroxyl group. However, if the hydrophobic group is a group having strong hydrophobicity, excellent water repellency can be imparted. The hydrocarbon group represented by R ¹ and R ² is a hydrophobic group, and as the total number of carbon atoms contained in R ¹ and R ² increases, the hydrogen element of R ¹ is replaced with a fluorine element. In the case of a hydrocarbon group, the larger the number of substituted fluorine elements, the stronger the hydrophobic group. With such a water-repellent protective film-forming agent having a hydrophobic group, a protective film exhibiting excellent water-repellent performance can be formed even when the hydroxyl group present on the wafer surface is low or the reactivity is low. Can do. The total number of carbon atoms contained in R ¹ and R ² in the formula [1] is 6 or more because the hydrophobic group contained in the formula [1] as 1 to 3 R ¹ and R ² It shows that the total number of all carbons is 6 or more.

In addition, the monovalent functional group represented by X in the general formula [1] whose element bonded to the silicon element is nitrogen is carbon, hydrogen, boron, nitrogen, phosphorus, oxygen, sulfur, silicon, germanium, fluorine , Chlorine, bromine, iodine, etc., any functional group may be used, for example, —NSi (CH ₃ ) ₃ group, —NSi (CH ₃ ) ₂ C ₄ H ₉ group, —NSi (CH ₃ ) ₂ C ₈ H ₁₇ group, —N (CH ₃ ) ₂ group, —N (C ₂ H ₅ ) ₂ group, —N (C ₃ H ₇ ) ₂ group, —N (CH ₃ ) (C ₂ H ₅ ) group , —NH (C ₂ H ₅ ) group, —NCO group, imidazole group, acetamide group and the like.

Furthermore, the monovalent functional group represented by X in the general formula [1] whose element bonded to the silicon element is oxygen is carbon, hydrogen, boron, nitrogen, phosphorus, oxygen, sulfur, silicon, germanium, fluorine , Chlorine, bromine, iodine, etc., as long as it is a functional group composed of, for example, —OCH ₃ group, —OC ₂ H ₅ group, —OC ₃ H ₇ group, —OCOCH ₃ group, —OCOCF ₃ group, etc. Is mentioned.

  Examples of the halogen group represented by X in the general formula [1] include -F group, -Cl group, -Br group, and -I group.

  The group represented by X in the general formula [1] reacts with a hydroxyl group on the wafer surface to form a bond between the silicon element in the silicon compound and the wafer surface, thereby forming a protective film. Can be formed.

In particular, the hydroxyl groups present on the surface of the materials such as titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium have low reactivity with the silicon compound, so that the hydroxyl groups are completely reacted. May not be possible. Even in such a case, if the hydrophobic groups represented by R ¹ and R ² are bulky, and R ¹ is a group having excellent hydrophobicity, excellent water repellency protection results. It is possible to obtain a membrane.

Further, when the substance such as titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium is a simple metal or a nitride, the amount of hydroxyl groups present on the surface of the substance is smaller than that of an oxide. There are few. Even in such a case, if the hydrophobic groups represented by R ¹ and R ² are bulky, and R ¹ is a group having excellent hydrophobicity, excellent water repellency protection results. It is possible to obtain a membrane.

Examples of the silicon compound represented by the general formula [1] include C ₄ F ₉ (CH ₃ ) ₂ SiCl, C ₅ F ₁₁ (CH ₃ ) ₂ SiCl, C ₆ F ₁₃ (CH ₃ ) ₂ SiCl, and C _{7. F 15 (CH 3) 2 SiCl} , C 8 F 17 (CH 3) 2 SiCl, C 5 F 11 (CH 3) HSiCl, C 6 F 13 (CH 3) HSiCl, C 7 F 15 (CH 3) HSiCl, _{C 8 F 17 (CH 3)} HSiCl, C 2 F 5 C 2 H 4 (CH 3) 2 SiCl, C 3 F 7 C 2 H 4 (CH 3) 2 SiCl, C 4 F 9 C 2 H 4 (CH ₃ ) ₂ SiCl, C ₅ F ₁₁ C ₂ H ₄ (CH ₃ ) ₂ SiCl, C ₆ F ₁₃ C ₂ H ₄ (CH ₃ ) ₂ SiCl, C ₇ F ₁₅ C ₂ H ₄ (CH ₃ ) ₂ SiCl, C _{F 17 C 2 H 4 (CH} 3) 2 SiCl, CF 3 C 2 H 4 (C 2 H 5) 2 SiCl, C 2 F 5 C 2 H 4 (C 2 H 5) 2 SiCl, C 3 F 7 C _{2 H 4 (C 2 H 5} ) 2 SiCl, C 4 F 9 C 2 H 4 (C 2 H 5) 2 SiCl, C 5 F 11 C 2 H 4 (C 2 H 5) 2 SiCl, C 6 F 13 _{C 2 H 4 (C 2 H} 5) 2 SiCl, C 7 F 15 C 2 H 4 (C 2 H 5) 2 SiCl, C 8 F 17 C 2 H 4 (C 2 H 5) 2 SiCl, CF 3 C _{2 H 4 (C 4 H 9} ) 2 SiCl, C 2 F 5 C 2 H 4 (C 4 H 9) 2 SiCl, C 3 F 7 C 2 H 4 (C 4 H 9) 2 SiCl, C 4 F 9 _{C 2 H 4 (C 4 H} 9) 2 SiCl, C 5 F 11 C 2 H 4 (C _{H 9) 2 SiCl, C 6} F 13 C 2 H 4 (C 4 H 9) 2 SiCl, C 7 F 15 C 2 H 4 (C 4 H 9) 2 SiCl, C 8 F 17 C 2 H 4 (C _{4 H 9) 2 SiCl, [} CF 3 C 2 H 4] 3 SiCl, [C 2 F 5 C 2 H 4] 3 SiCl, [C 3 F 7 C 2 H 4] 3 SiCl, [C 4 F 9 C _{2 H 4] 3 SiCl, [} C 5 F 11 C 2 H 4] 3 SiCl, [C 6 F 13 C 2 H 4] 3 SiCl, [C 7 F 15 C 2 H 4] 3 SiCl, [C 8 F ₁₇ C ₂ H ₄ ] ₃ SiCl, C ₃ F ₇ C ₂ H ₄ (CH ₃ ) SiCl ₂ , C ₄ F ₉ C ₂ H ₄ (CH ₃ ) SiCl ₂ , C ₅ F ₁₁ C ₂ H ₄ (CH ₃ ) SiCl ₂ , C ₆ F ₁₃ C ₂ H ₄ (CH ₃ ) S _{iCl 2, C 7 F 15 C} 2 H 4 (CH 3) SiCl 2, C 8 F 17 C 2 H 4 (CH 3) SiCl 2, C 4 F 9 C 2 H 4 SiCl 3, C 5 F 11 C 2 Examples thereof include chlorosilane compounds such as H ₄ SiCl ₃ , C ₆ F ₁₃ C ₂ H ₄ SiCl ₃ , C ₇ F ₁₅ C ₂ H ₄ SiCl ₃ , and C ₈ F ₁₇ C ₂ H ₄ SiCl ₃ .

Also, for example, C ₄ F ₉ (CH ₃ ) ₂ SiOCH ₃ , C ₅ F ₁₁ (CH ₃ ) ₂ SiOCH ₃ , C ₆ F ₁₃ (CH ₃ ) ₂ SiOCH ₃ , C ₇ F ₁₅ (CH ₃ ) ₂ SiOCH ₃ , C ₈ F ₁₇ (CH ₃ ) ₂ SiOCH ₃ , C ₉ F ₁₉ (CH ₃ ) ₂ SiOCH ₃ , C ₁₀ F ₂₁ (CH ₃ ) ₂ SiOCH ₃ , C ₁₁ F ₂₃ (CH ₃ ) ₂ SiOCH ₃ , _{C 12 F 25 (CH 3)} 2 SiOCH 3, C 13 F 27 (CH 3) 2 SiOCH 3, C 14 F 29 (CH 3) 2 SiOCH 3, C 15 F 31 (CH 3) 2 SiOCH 3, C 16 _{F 33 (CH 3) 2 SiOCH} 3, C 17 F 35 (CH 3) 2 SiOCH 3, C 18 F 37 (CH 3) 2 SiOCH _{, C 3 F 7 C 2 H} 4 (CH 3) HSiOCH 3, C 4 F 9 C 2 H 4 (CH 3) HSiOCH 3, C 5 F 11 C 2 H 4 (CH 3) HSiOCH 3, C 6 F 13 _{C 2 H 4 (CH 3)} HSiOCH 3, C 7 F 15 C 2 H 4 (CH 3) HSiOCH 3, C 8 F 17 C 2 H 4 (CH 3) HSiOCH 3, C 2 F 5 C 2 H 4 ( CH ₃ ) ₂ SiOCH ₃ , C ₃ F ₇ C ₂ H ₄ (CH ₃ ) ₂ SiOCH ₃ , C ₄ F ₉ C ₂ H ₄ (CH ₃ ) ₂ SiOCH ₃ , C ₅ F ₁₁ C ₂ H ₄ (CH ₃ ) ₂ SiOCH ₃ , C ₆ F ₁₃ C ₂ H ₄ (CH ₃ ) ₂ SiOCH ₃ , C ₇ F ₁₅ C ₂ H ₄ (CH ₃ ) ₂ SiOCH ₃ , C ₈ F ₁₇ C ₂ H ₄ (CH ₃ ) ₂ S _{OCH 3, CF 3 C 2 H} 4 (C 2 H 5) 2 SiOCH 3, C 2 F 5 C 2 H 4 (C 2 H 5) 2 SiOCH 3, C 3 F 7 C 2 H 4 (C 2 H 5 ) ₂ SiOCH ₃ , C ₄ F ₉ C ₂ H ₄ (C ₂ H ₅ ) ₂ SiOCH ₃ , C ₅ F ₁₁ C ₂ H ₄ (C ₂ H ₅ ) ₂ SiOCH ₃ , C ₆ F ₁₃ C ₂ H ₄ ( _{C 2 H 5) 2 SiOCH 3} , C 7 F 15 C 2 H 4 (C 2 H 5) 2 SiOCH 3, C 8 F 17 C 2 H 4 (C 2 H 5) 2 SiOCH 3, [CF 3 C 2 _{H 4] 3 SiOCH 3, [} C 2 F 5 C 2 H 4] 3 SiOCH 3, [C 3 F 7 C 2 H 4] 3 SiOCH 3, [C 4 F 9 C 2 H 4] 3 SiOCH 3, [ _{C 5 F 11 C 2 H 4} ] 3 SiOC _{3, [C 6 F 13 C} 2 H 4] 3 SiOCH 3, [C 7 F 15 C 2 H 4] 3 SiOCH 3, [C 8 F 17 C 2 H 4] 3 SiOCH 3, C 3 F 7 C 2 _{H 4 (CH 3) Si (} OCH 3) 2, C 4 F 9 C 2 H 4 (CH 3) Si (OCH 3) 2, C 5 F 11 C 2 H 4 (CH 3) Si (OCH 3) 2 _{, C 6 F 13 C 2 H} 4 (CH 3) Si (OCH 3) 2, C 7 F 15 C 2 H 4 (CH 3) Si (OCH 3) 2, C 8 F 17 C 2 H 4 (CH 3 _{) Si (OCH 3) 2,} C 4 F 9 C 2 H 4 Si (OCH 3) 3, C 5 F 11 C 2 H 4 Si (OCH 3) 3, C 6 F 13 C 2 H 4 Si (OCH 3 _{) 3, C 7 F 15 C} 2 H 4 Si (OCH 3) 3, _{8 F 17 C 2 H 4 Si} (OCH 3) 3, C 2 F 5 C 2 H 4 (CH 3) 2 SiOC 2 H 5, C 3 F 7 C 2 H 4 (CH 3) 2 SiOC 2 H 5, _{C 4 F 9 C 2 H 4} (CH 3) 2 SiOC 2 H 5, C 5 F 11 C 2 H 4 (CH 3) 2 SiOC 2 H 5, C 6 F 13 C 2 H 4 (CH 3) 2 SiOC _{2 H 5, C 7 F 15} C 2 H 4 (CH 3) 2 SiOC 2 H 5, C 8 F 17 C 2 H 4 (CH 3) 2 SiOC 2 H 5, C 3 F 7 C 2 H 4 (CH _{3) Si (OC 2 H 5} ) 2, C 4 F 9 C 2 H 4 (CH 3) Si (OC 2 H 5) 2, C 5 F 11 C 2 H 4 (CH 3) Si (OC 2 H 5 ) ₂ , C ₆ F ₁₃ C ₂ H ₄ (CH ₃ ) Si (OC ₂ H ₅ ) ₂ , C ₇ F ₁₅ C ₂ H ₄ (CH ₃ ) Si (OC ₂ H ₅ ) ₂ , C ₈ F ₁₇ C ₂ H ₄ (CH ₃ ) Si (OC ₂ H ₅ ) ₂ , C ₄ F ₉ C _{2 H 4 Si (OC 2 H} 5) 3, C 5 F 11 C 2 H 4 Si (OC 2 H 5) 3, C 6 F 13 C 2 H 4 Si (OC 2 H 5) 3, C 7 F 15 Examples thereof include alkoxysilane compounds such as C ₂ H ₄ Si (OC ₂ H ₅ ) ₃ and C ₈ F ₁₇ C ₂ H ₄ Si (OC ₂ H ₅ ) ₃ .

Also, for example, C ₂ F ₅ C ₂ H ₄ (CH ₃ ) ₂ SiNCO, C ₃ F ₇ C ₂ H ₄ (CH ₃ ) ₂ SiNCO, C ₄ F ₉ C ₂ H ₄ (CH ₃ ) ₂ SiNCO, C _{5 F 11 C 2 H 4 (} CH 3) 2 SiNCO, C 6 F 13 C 2 H 4 (CH 3) 2 SiNCO, C 7 F 15 C 2 H 4 (CH 3) 2 SiNCO, C 8 F 17 C 2 _{H 4 (CH 3) 2 SiNCO} , C 3 F 7 C 2 H 4 (CH 3) Si (NCO) 2, C 4 F 9 C 2 H 4 (CH 3) Si (NCO) 2, C 5 F 11 C _{2 H 4 (CH 3) Si} (NCO) 2, C 6 F 13 C 2 H 4 (CH 3) Si (NCO) 2, C 7 F 15 C 2 H 4 (CH 3) Si (NCO) 2, C ₈ F ₁₇ C ₂ H ₄ (CH ₃ ) Si (N _{CO) 2, C 4 F 9} C 2 H 4 Si (NCO) 3, C 5 F 11 C 2 H 4 Si (NCO) 3, C 6 F 13 C 2 H 4 Si (NCO) 3, C 7 F 15 Examples thereof include isocyanate silane compounds such as C ₂ H ₄ Si (NCO) ₃ and C ₈ F ₁₇ C ₂ H ₄ Si (NCO) ₃ .

Also, for example, C ₂ F ₅ C ₂ H ₄ (CH ₃ ) ₂ SiNH ₂ , C ₃ F ₇ C ₂ H ₄ (CH ₃ ) ₂ SiNH ₂ , C ₄ F ₉ C ₂ H ₄ (CH ₃ ) ₂ SiNH ₂ , C ₅ F ₁₁ C ₂ H ₄ (CH ₃ ) ₂ SiNH ₂ , C ₆ F ₁₃ C ₂ H ₄ (CH ₃ ) ₂ SiNH ₂ , C ₇ F ₁₅ C ₂ H ₄ (CH ₃ ) ₂ SiNH ₂ , _{C 8 F 17 C 2 H 4} (CH 3) 2 SiNH 2, [C 2 F 5 C 2 H 4 (CH 3) 2 Si] 2 NH, [C 3 F 7 C 2 H 4 (CH 3) 2 Si _{] 2 NH, [C 4 F} 9 C 2 H 4 (CH 3) 2 Si] 2 NH, [C 5 F 11 C 2 H 4 (CH 3) 2 Si] 2 NH, [C 6 F 13 C 2 H _{4 (CH 3) 2 Si]} 2 NH, [C 7 F 15 C 2 H 4 ( _{H 3) 2 Si] 2 NH} , [C 8 F 17 C 2 H 4 (CH 3) 2 Si] 2 NH, [CF 3 C 2 H 2 (C 2 H 5) 2 Si] 2 NH, [C 2 _{F 5 C 2 H 4 (C} 2 H 5) 2 Si] 2 NH, [C 3 F 7 C 2 H 4 (C 2 H 5) 2 Si] 2 NH, [C 4 F 9 C 2 H 4 (C _{2 H 5) 2 Si] 2} NH, [C 5 F 11 C 2 H 4 (C 2 H 5) 2 Si] 2 NH, [C 6 F 13 C 2 H 4 (C 2 H 5) 2 Si] 2 _{NH, [C 7 F 15 C} 2 H 4 (C 2 H 5) 2 Si] 2 NH, [C 8 F 17 C 2 H 4 (C 2 H 5) 2 Si] 2 NH, {[CF 3 C 2 _{H 4] 3 Si} 2 NH} , {[C 2 F 5 C 2 H 4] 3 Si} 2 NH, {[C 3 F 7 C 2 H 4] 3 Si} _{NH, {[C 4 F 9} C 2 H 4] 3 Si} 2 NH, {[C 5 F 11 C 2 H 4] 3 Si} 2 NH, {[C 6 F 13 C 2 H 4] 3 Si} ₂ NH, {[C ₇ F ₁₅ C ₂ H ₄ ] ₃ Si} ₂ NH, {[C ₈ F ₁₇ C ₂ H ₄ ] ₃ Si} ₂ NH, [C ₂ F ₅ C ₂ H ₄ (CH ₃ ) ₂ Si] ₃ N, [C ₃ F ₇ C ₂ H ₄ (CH ₃ ) ₂ Si] ₃ N, [C ₄ F ₉ C ₂ H ₄ (CH ₃ ) ₂ Si] ₃ N, [C ₅ F ₁₁ C ₂ H ₄ (CH ₃ ) ₂ Si] ₃ N, [C ₆ F ₁₃ C ₂ H ₄ (CH ₃ ) ₂ Si] ₃ N, [C ₇ F ₁₅ C ₂ H ₄ (CH ₃ ) ₂ Si] ₃ N , [C ₈ F ₁₇ C ₂ H ₄ (CH ₃ ) ₂ Si] ₃ N, C ₄ F ₉ (CH ₃ ) ₂ SiN (CH ₃ ) ₂ , C _{5 F 11 (CH 3) 2 SiN} (CH 3) 2, C 6 F 13 (CH 3) 2 SiN (CH 3) 2, C 7 F 15 (CH 3) 2 SiN (CH 3) 2, C 8 F 17 (CH ₃ ) ₂ SiN (CH ₃ ) ₂ , C ₉ F ₁₉ (CH ₃ ) ₂ SiN (CH ₃ ) ₂ , C ₁₀ F ₂₁ (CH ₃ ) ₂ SiN (CH ₃ ) ₂ , C ₅ F ₁₁ (CH _{3) HSiN (CH 3) 2} , C 6 F 13 (CH 3) HSiN (CH 3) 2, C 7 F 15 (CH 3) HSiN (CH 3) 2, C 8 F 17 (CH 3) HSiN (CH _{3) 2, C 9 F 19} (CH 3) HSiN (CH 3) 2, C 10 F 21 (CH 3) HSiN (CH 3) 2, C 2 F 5 C 2 H 4 (CH 3) 2 SiN (CH _{3) 2, C 3 F 7} C 2 _{4 (CH 3) 2 SiN (} CH 3) 2, C 4 F 9 C 2 H 4 (CH 3) 2 SiN (CH 3) 2, C 5 F 11 C 2 H 4 (CH 3) 2 SiN (CH 3 ) ₂ , C ₆ F ₁₃ C ₂ H ₄ (CH ₃ ) ₂ SiN (CH ₃ ) ₂ , C ₇ F ₁₅ C ₂ H ₄ (CH ₃ ) ₂ SiN (CH ₃ ) ₂ , C ₈ F ₁₇ C ₂ H ₄ (CH ₃ ) ₂ SiN (CH ₃ ) ₂ , CF ₃ C ₂ H ₄ (C ₂ H ₅ ) ₂ SiN (CH ₃ ) ₂ , C ₂ F ₅ C ₂ H ₄ (C ₂ H ₅ ) ₂ SiN ( _{CH 3) 2, C 3 F} 7 C 2 H 4 (C 2 H 5) 2 SiN (CH 3) 2, C 4 F 9 C 2 H 4 (C 2 H 5) 2 SiN (CH 3) 2, C ₅ F ₁₁ C ₂ H ₄ (C ₂ H ₅ ) ₂ SiN (CH ₃ ) ₂ , C ₆ F ₁₃ C ₂ H ₄ (C ₂ H ₅ ) ₂ SiN (CH ₃ ) ₂ , C ₇ F ₁₅ C ₂ H ₄ (C ₂ H ₅ ) ₂ SiN (CH ₃ ) ₂ , C ₈ F ₁₇ C ₂ H ₄ (C _{2 H 5) 2 SiN (CH 3} ) 2, [CF 3 C 2 H 4] 3 SiN (CH 3) 2, [C 2 F 5 C 2 H 4] 3 SiN (CH 3) 2, [C 3 F 7 _{C 2 H 4] 3 SiN (} CH 3) 2, [C 4 F 9 C 2 H 4] 3 SiN (CH 3) 2, [C 5 F 11 C 2 H 4] 3 SiN (CH 3) 2, [ _{C 6 F 13 C 2 H 4} ] 3 SiN (CH 3) 2, [C 7 F 15 C 2 H 4] 3 SiN (CH 3) 2, [C 8 F 17 C 2 H 4] 3 SiN (CH 3 _{) 2, C 3 F 7 C} 2 H 4 (CH 3) Si [N (CH 3) 2] 2, C 4 F 9 _{2 H 4 (CH 3) Si} [N (CH 3) 2] 2, C 5 F 11 C 2 H 4 (CH 3) Si [N (CH 3) 2] 2, C 6 F 13 C 2 H 4 ( _{CH 3) Si [N (CH} 3) 2] 2, C 7 F 15 C 2 H 4 (CH 3) Si [N (CH 3) 2] 2, C 8 F 17 C 2 H 4 (CH 3) Si [N (CH ₃ ) ₂ ] ₂ , C ₄ F ₉ C ₂ H ₄ Si [N (CH ₃ ) ₂ ] ₃ , C ₅ F ₁₁ C ₂ H ₄ Si [N (CH ₃ ) ₂ ] ₃ , C _{6 F 13 C 2 H 4 Si [} N (CH 3) 2] 3, C 7 F 15 C 2 H 4 Si [N (CH 3) 2] 3, C 8 F 17 C 2
H ₄ Si [N (CH ₃ ) ₂ ] ₃ , C ₄ F ₉ (CH ₃ ) ₂ SiN (C ₂ H ₅ ) ₂ , C ₅ F ₁₁ (CH ₃ ) ₂ SiN (C ₂ H ₅ ) ₂ , C ₆ F ₁₃ (CH ₃ ) ₂ SiN (C ₂ H ₅ ) ₂ , C ₇ F ₁₅ (CH ₃ ) ₂ SiN (C ₂ H ₅ ) ₂ , C ₈ F ₁₇ (CH ₃ ) ₂ SiN (C ₂ H _{5 ) 2, C 9 F 19 (} CH 3) 2 SiN (C 2 H 5) 2, C 10 F 21 (CH 3) 2 SiN (C 2 H 5) 2, C 2 F 5 C 2 H 4 (CH 3 ) ₂ SiN (C ₂ H ₅ ) ₂ , C ₃ F ₇ C ₂ H ₄ (CH ₃ ) ₂ SiN (C ₂ H ₅ ) ₂ , C ₄ F ₉ C ₂ H ₄ (CH ₃ ) ₂ SiN (C ₂ ) H ₅ ) ₂ , C ₅ F ₁₁ C ₂ H ₄ (CH ₃ ) ₂ SiN (C ₂ H ₅ ) ₂ , C ₆ F ₁₃ C ₂ H ₄ (CH ₃ ) ₂ SiN (C ₂ H ₅ ) ₂ , C ₇ F ₁₅ C ₂ H ₄ (CH ₃ ) ₂ SiN (C ₂ H ₅ ) ₂ , C ₈ F ₁₇ C ₂ H ₄ ( _{CH 3) 2 SiN (C 2} H 5) 2, CF 3 C 2 H 4 (C 2 H 5) 2 SiN (C 2 H 5) 2, C 2 F 5 C 2 H 4 (C 2 H 5) 2 _{SiN (C 2 H 5) 2} , C 3 F 7 C 2 H 4 (C 2 H 5) 2 SiN (C 2 H 5) 2, C 4 F 9 C 2 H 4 (C 2 H 5) 2 SiN ( _{C 2 H 5) 2, C} 5 F 11 C 2 H 4 (C 2 H 5) 2 SiN (C 2 H 5) 2, C 6 F 13 C 2 H 4 (C 2 H 5) 2 SiN (C 2 _{H 5) 2, C 7 F} 15 C 2 H 4 (C 2 H 5) 2 SiN (C 2 H 5) 2, C 8 F 17 C 2 H 4 _{(C 2 H 5) 2 SiN} (C 2 H 5) 2, [CF 3 C 2 H 4] 3 SiN (C 2 H 5) 2, [C 2 F 5 C 2 H 4] 3 SiN (C 2 H _{5) 2, [C 3 F} 7 C 2 H 4] 3 SiN (C 2 H 5) 2, [C 4 F 9 C 2 H 4] 3 SiN (C 2 H 5) 2, [C 5 F 11 C _{2 H 4] 3 SiN (C} 2 H 5) 2, [C 6 F 13 C 2 H 4] 3 SiN (C 2 H 5) 2, [C 7 F 15 C 2 H 4] 3 SiN (C 2 H ₅ ) ₂ , and aminosilane compounds such as [C ₈ F ₁₇ C ₂ H ₄ ] ₃ SiN (C ₂ H ₅ ) ₂ .

In addition, the sum of a and b in the general formula [1] may be an integer of 1 to 3, but when the sum of a and b is 1 or 2, if the chemical solution is stored for a long time, it may be mixed with moisture. The polymerization reaction between the silicon compounds tends to occur, and it tends to be difficult to stably form a water repellent protective film on the wafer surface. Considering this, a compound in which the sum of a and b in the general formula [1] is 3, that is, a silicon compound represented by the following general formula [2] is preferable.
R ¹ _a R ² _b SiX [2]
[In the formula [2], R ¹ are each independently a hydrocarbon group in which at least one hydrogen element having 1 to 18 carbon atoms is substituted with a fluorine element, and R ² are each independently , A hydrogen group, or a hydrocarbon group having 1 to 18 carbon atoms, the total number of carbon atoms contained in R ¹ and R ² in the formula [2] is 6 or more, and X is bonded to a silicon element. A monovalent functional group in which the element to be bonded is nitrogen, a monovalent functional group in which the element bonded to the silicon element is oxygen, or a halogen group. A is an integer of 1 to 3, b is an integer of 0 to 2, and the sum of a and b is 3. ]

Further, among the silicon compounds in which the sum of a and b in the general formula [1] is 3, b is 2, and both R ² are methyl groups, that is, the following general formula [3] The silicon compound to be used is preferable because of its high reactivity with the hydroxyl group on the wafer surface. This is because the steric hindrance by the hydrophobic group greatly affects the reactivity in the reaction between the hydroxyl group on the wafer surface and the group represented by X of the silicon compound, and the alkyl chain bonded to the silicon element is the most. This is because the remaining two except the long one are preferably shorter.
R ³ (CH ₃ ) ₂ SiX [3]
[In the formula [3], R ³ is a hydrocarbon group in which at least one hydrogen element having 4 to 18 carbon atoms is substituted with a fluorine element, and X is a monovalent element in which the element bonded to the silicon element is nitrogen. A monovalent functional group in which the element bonded to the silicon element is oxygen, or a halogen group. ]

  The water-repellent protective film forming agent may be contained at least in the water-repellent protective film-forming chemical solution, and can be diluted using various organic solvents. The organic solvent only needs to dissolve the water-repellent protective film forming agent. For example, hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, alcohols, polyhydric alcohols. And derivatives thereof, nitrogen-containing compound solvents and the like are preferably used. When water is used as the solvent to be diluted, the group represented by X of the silicon compound is hydrolyzed with water to form a silanol group (Si—OH), and the generated silanol groups undergo a condensation reaction to form the silicon. The compounds combine to form a dimer. Since this dimer has low reactivity with the hydroxyl group on the wafer surface, the wafer surface cannot be made sufficiently water-repellent or the time required for water-repelling becomes longer, so it is preferable to use water as a solvent. Absent.

  Furthermore, since the silicon compound easily reacts with a protic solvent, it is particularly preferable to use an aprotic solvent as the organic solvent because water repellency is easily developed on the wafer surface 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. Compound solvents 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, and dioxane.Examples of the ketones include acetone, acetylacetone, methyl ethyl ketone, methyl propyl ketone, and methyl butyl ketone. Examples of halogen solvents include perfluorocarbons such as perfluorooctane, perfluorononane, perfluorocyclopentane, perfluorocyclohexane, hexafluorobenzene, 1, 1, 1, 3, 3-pentafluorobutane, Hydrofluorocarbons such as Kutafluorocyclopentane, 2,3-dihydrodecafluoropentane, Zeolora H (manufactured by Nippon Zeon), methyl perfluoroisobutyl ether, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, ethyl perfluoroisobutyl ether, Asahi Hydrofluoroethers such as Clin AE-3000 (manufactured by Asahi Glass), Novec HFE-7100, Novec HFE-7200, Novec7300, and Novec7600 (all manufactured by 3M), chlorocarbons such as tetrachloromethane, hydrochlorocarbons such as chloroform, dichloro Chlorofluorocarbons such as difluoromethane, 1,1-dichloro-2,2,3,3,3-pentafluoropropane, 1,3- Hydrochlorofluorocarbons such as chloro-1,1,2,2,3-pentafluoropropane, 1-chloro-3,3,3-trifluoropropene, 1,2-dichloro-3,3,3-trifluoropropene Examples of the sulfoxide solvent include dimethyl sulfoxide, and examples of the polyhydric alcohol derivative having no hydroxyl group include diethylene glycol monoethyl ether acetate, ethylene glycol, and the like. Examples of nitrogen-containing compound solvents having no N—H bond include monomethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and the like. Te is, N, N- dimethylformamide, N, N- dimethylacetamide, N- methyl-2-pyrrolidone, triethylamine, pyridine and the like.

  Furthermore, it is preferable to use a nonflammable organic solvent because the water repellent protective film-forming chemical solution becomes nonflammable or has a high flash point. Many halogen-containing solvents are nonflammable, and the nonflammable halogen-containing solvent can be suitably used as a nonflammable organic solvent.

  Further, it is preferable to use a polar solvent as the organic solvent because the reaction between the silicon compound as the protective film forming agent and the hydroxyl group on the wafer surface is likely to proceed.

  The organic solvent may be present as long as it is a trace amount of water. However, when this moisture is contained in a large amount in the solvent, the silicon compound may be hydrolyzed by the moisture to reduce the reactivity. For this reason, it is preferable to reduce the amount of water in the solvent, and the amount of water is preferably less than 1 mole in terms of molar ratio to the silicon compound when mixed with the silicon compound. It is particularly preferable to make it less than 5 mole times.

  The water-repellent protective film forming chemical is preferably contained in an amount of 0.1 to 50% by mass of the water-repellent protective film-forming agent in a total amount of 100% by mass of the chemical. Is 0.3 to 20% by mass with respect to 100% by mass of the total amount of the chemical solution. If the water-repellent protective film forming agent is less than 0.1% by mass, the effect of imparting water repellency tends to be insufficient, and if it exceeds 50% by mass, components derived from the water-repellent protective film forming agent are impurities on the wafer surface after cleaning. As such, there is a concern that it remains as such. Moreover, since the usage-amount of a water repellent protective film formation agent increases, it is unpreferable also from a cost viewpoint.

  Further, a catalyst may be added to the chemical solution in order to promote the reaction between the silicon compound and the hydroxyl group on 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 alkylamines, aprotic nitrogen-containing solvents such as pyridine and dimethylformamide, salts such as ammonium sulfide, potassium acetate and methylhydroxyamine hydrochloride, and metal complexes and metal salts such as tin, aluminum and titanium Preferably used. In particular, considering the catalytic effect, acids such as trifluoroacetic acid, trifluoroacetic anhydride, trifluoromethanesulfonic acid, trifluoromethanesulfonic anhydride, sulfuric acid, and hydrogen chloride are preferable, and the acid does not contain moisture. Is preferred. The catalyst may form a part of the water-repellent protective film by reaction.

In particular, when the number of carbon atoms of the hydrophobic group R ¹ or R ² of the silicon compound represented by the general formula [1] increases, the reactivity of the silicon compound with respect to the hydroxyl group on the wafer surface may decrease due to steric hindrance. . In this case, by adding an acid not containing water as a catalyst, the reaction between the hydroxyl group on the wafer surface and the silicon compound is promoted to compensate for the decrease in reactivity due to the steric hindrance of the hydrophobic group as described above. There is a case.

  The addition amount of the catalyst is preferably 0.01 to 100% by mass with respect to 100% by mass of the total amount of the silicon compound. If the amount added is small, the catalytic effect is lowered, which is not preferable. Moreover, even if it adds excessively, a catalyst effect will not improve, but when it increases more than a silicon compound, a catalyst effect may fall conversely. Furthermore, there is a concern that the impurities may remain on the wafer surface as impurities. For this reason, 0.01-100 mass% of the said catalyst addition amount is preferable, More preferably, it is 0.1-50 mass%, More preferably, it is 0.2-20 mass%.

  Next, the wafer cleaning method of the present invention will be described.

  In general, a wafer that is cleaned using the chemical solution of the present invention is generally one that has undergone a pretreatment step in which the wafer surface is a surface having a fine uneven pattern.

  In the pretreatment step, the method is not limited as long as a fine pattern can be formed on the wafer surface. As a general method, after applying a resist to the wafer surface, the resist is exposed through a resist mask. Then, a resist having a desired concavo-convex pattern is produced by etching away the exposed resist or the resist that has not been exposed. 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 wafer having a fine uneven pattern is obtained.

In addition, as the wafer, the surface of a silicon wafer, a wafer composed of a plurality of components including silicon and / or silica (SiO ₂ ), a silicon carbide wafer, a sapphire wafer, various compound semiconductor wafers, a plastic wafer, etc. is made of titanium, A multilayer film is formed on a wafer coated with a metal material layer of titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium, and at least one of the layers is formed of the metal material. The above-mentioned concavo-convex pattern forming step is performed in a layer including a layer of the metal-based substance. Moreover, when the said uneven | corrugated pattern is formed, the thing in which at least one part of this uneven | corrugated pattern becomes this metal-type substance is also contained. Furthermore, the thing which formed the uneven | corrugated pattern on the wafer and formed the layer of the said metal-type substance on the surface of the uneven | corrugated pattern is also included.

  In addition, the protective film can be formed on the surface of the metal-based material even on a wafer composed of a plurality of components including the metal-based material. As a wafer composed of the plurality of components, the metal-based material is formed on the wafer surface, or when a concavo-convex pattern is formed, at least a part of the concavo-convex pattern becomes the metal-based material. Also included. In addition, it is at least the surface of the said metal-type substance part in the said uneven | corrugated pattern that can form a protective film with the chemical | medical solution of this invention.

The present invention provides a wafer having a concavo-convex pattern formed on the surface, wherein at least a part of the concave surface of the concavo-convex pattern is selected from the group consisting of titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium. Cleaning a wafer containing one substance,
A water-based cleaning liquid cleaning step for cleaning the wafer surface with a water-based cleaning liquid. A water-repellent protective film-forming chemical solution containing a water-repellent protective film-forming agent for forming a water-repellent protective film on the wafer surface is formed in at least a recess of the wafer. Holding and forming a water-repellent protective film on the surface of the recess, forming a water-repellent protective film, removing the liquid on the wafer surface, removing the water-repellent protective film, removing the water-repellent protective film from the surface of the recess Have

  Examples of the aqueous cleaning liquid include water or water in which at least one of organic solvents, acids, and alkalis is mixed in water as a main component (for example, the water content is 50% by mass or more). Is mentioned.

  In the aqueous cleaning, after removing the resist, removing particles on the wafer surface, etc., when removing the aqueous cleaning liquid by drying or the like, if the width of the concave portion is small and the aspect ratio of the convex portion is large, pattern collapse occurs. It becomes easy. The concavo-convex pattern is defined as shown in FIGS. FIG. 1 is a schematic view of a wafer 1 whose surface has a concavo-convex pattern 2 as viewed from the perspective, and FIG. 2 shows a part of the a-a ′ cross section in FIG. 1. 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.

  Further, in the aqueous cleaning liquid cleaning step, in the portion made of at least one substance selected from the group consisting of titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium, in which the aqueous cleaning liquid is held and is in contact By contact with the aqueous cleaning solution, a part of the surface is oxidized to form a hydroxyl group. Although this oxidation is slight, the water-repellent protective film forming agent provided in the present invention has strong hydrophobicity, and thus reacts with a part of hydroxyl groups formed by oxidation to form an excellent water-repellent protective film. It is possible.

  This oxidation of the wafer surface proceeds even if the aqueous cleaning liquid is pure water, but it tends to proceed more easily if the aqueous cleaning liquid is strongly acidic or the temperature of the aqueous cleaning liquid is high. An acid may be added to the cleaning liquid, or the temperature of the aqueous cleaning liquid may be increased. Furthermore, hydrogen peroxide or ozone may be added for the purpose of promoting oxidation.

  In the wafer cleaning method of the present invention, in order to perform efficient cleaning without causing pattern collapse, the water-repellent protective film forming step from the water-based cleaning solution cleaning step is always held in at least the concave portion of the wafer. It is preferable to carry out in the state. In addition, when the water-repellent protective film forming chemical liquid held in the concave portion of the wafer is replaced with another liquid after the water-repellent protective film forming step, the liquid is always held in at least the concave portion of the wafer as described above. It is preferable to carry out in the state. In the present invention, the cleaning method of the wafer is not particularly limited as long as the aqueous cleaning liquid, the chemical liquid, and other liquids can be held in at least the concave portions of the concave / convex pattern of the wafer. As a wafer cleaning method, a wafer cleaning method represented by spin cleaning in which a wafer is cleaned one by one by supplying liquid to the vicinity of the rotation center while rotating the wafer while holding the wafer substantially horizontal, or a plurality of cleaning methods in the cleaning tank. One example is a batch system in which a single wafer is immersed and washed. The form of the chemical liquid or cleaning liquid when supplying the aqueous cleaning liquid, the chemical liquid or other liquid to at least the concave portion of the concave / convex pattern of the wafer is particularly limited as long as it becomes a liquid when held in the concave portion. For example, there are liquid, vapor and the like.

  Next, the water repellent protective film forming step will be described. The transition from the water-based cleaning step to the water-repellent protective film forming step is performed by replacing the water-based cleaning solution held in at least the concave portion of the concave-convex pattern of the wafer in the water-based cleaning step with a water-repellent protective film-forming chemical solution. . In the replacement of the water-based cleaning liquid with the water-repellent protective film-forming chemical liquid, it may be replaced directly or after being replaced one or more times with a different cleaning liquid A (hereinafter simply referred to as “cleaning liquid A”). It may be replaced with a water repellent protective film forming chemical. Preferable examples of the cleaning liquid A include water, an organic solvent, a mixture of water and an organic solvent, or a mixture of at least one of acid, alkali, and surfactant. Examples of the organic solvent that is one of the preferred examples of the cleaning liquid A include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, alcohols, polyhydric alcohol derivatives, And nitrogen-containing compound solvents.

  The formation of the water-repellent protective film in the water-repellent protective film forming step is performed by holding a water-repellent protective film-forming chemical at least in the concave portions of the concave / convex pattern of the wafer. FIG. 3 is a schematic view showing a state in which the concave portion 4 holds the water repellent protective film forming chemical 8. The wafer in the schematic diagram of FIG. 3 shows a part of the a-a ′ cross section of FIG. 1. In the water repellent protective film forming step, the water repellent protective film forming chemical is supplied to the wafer 1 on which the concave / convex pattern 2 is formed. At this time, the water-repellent protective film forming chemical solution is held at least in the concave portion 4 as shown in FIG. 3, and the surface of the concave portion 4 is water-repellent. Note that the protective film of the present invention does not necessarily have to be formed continuously, and does not necessarily have to be formed uniformly, but because it can impart better water repellency, More preferably, it is uniformly formed.

  In the protective film forming step, when the temperature of the chemical solution is increased, the protective film is easily formed in a shorter time, but the stability of the chemical solution may be impaired due to boiling or evaporation of the water repellent protective film forming chemical solution. Therefore, the chemical solution is preferably maintained at 10 to 160 ° C., particularly preferably 15 to 120 ° C.

  FIG. 4 shows a schematic diagram in the case where the liquid 9 is held in the recess 4 that has been made water-repellent by the water-repellent protective film forming agent. The wafer in the schematic diagram of FIG. 4 shows a part of the a-a ′ cross section of FIG. 1. A water repellent protective film 10 is formed on the surface of the recess 4 by a water repellent protective film forming agent. At this time, the liquid 9 held in the recess 4 may be the above-described chemical liquid or a liquid (cleaning liquid B) after the chemical liquid is replaced with a different cleaning liquid B (hereinafter sometimes simply referred to as “cleaning liquid B”). , A liquid in the middle of substitution (a mixed solution of a chemical solution and a cleaning solution) may be used. The water repellent protective film 10 is held on the wafer surface even when the liquid 9 is removed from the recess 4.

  Preferable examples of the cleaning liquid B include water, an organic solvent, a mixture of water and an organic solvent, or a mixture of at least one of acid, alkali, and surfactant. Examples of the organic solvent that is one of the preferred examples of the cleaning liquid B include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, alcohols, polyhydric alcohols, many And derivatives of polyhydric alcohols, nitrogen-containing compound solvents, and the like.

When the liquid is held in the concave portion of the wafer having the concave / convex pattern, a capillary force acts on the concave portion. The magnitude of this capillary force is the absolute value of P obtained by the following formula as described above.
P = 2 × γ × cos θ / S
(Wherein γ is the surface tension of the liquid held in the recess, θ is the contact angle between the recess surface and the liquid held in the recess, and S is the width of the recess.)
When a water-repellent protective film exists on the surface of the recess as in the recess 4 of FIG. 4, θ is increased and the absolute value of P is decreased. From the viewpoint of suppressing pattern collapse, the smaller the absolute value of P, the better. It is ideal to adjust the contact angle with the liquid to be removed to around 90 ° to bring the capillary force as close as possible to 0.0 MN / m ^2. It is.

As shown in FIG. 4, when the protective film 10 is formed on the surface of the recess, the contact angle when assuming that water is held on the surface is preferably 50 to 130 ° because pattern collapse hardly occurs. The closer the contact angle is to 90 °, the smaller the capillary force acting on the recess and the more difficult the pattern collapse occurs, so 70 to 110 ° is particularly preferable. For example, in the case of a line-and-space pattern wafer with a line width (width of recess) of 45 nm, the capillary force is preferably 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. Further, when the capillary force becomes small, pattern collapse hardly occurs. Therefore, the capillary force is particularly preferably 1.1 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.

Next, the liquid removal process will be described. The liquid held in the recess is the chemical liquid, the cleaning liquid B, or a mixed liquid of the chemical liquid and the cleaning liquid. As a method for removing the liquid, known drying methods such as natural drying, air drying, N ₂ gas drying, spin drying method, IPA (2-propanol) vapor drying, Marangoni drying, heat drying, hot air drying, vacuum drying, etc. It is preferable to carry out by. In order to efficiently remove the liquid, the retained liquid may be drained and removed, and then the remaining liquid may be dried.

  Finally, the water repellent protective film removing step will be described. When removing the water-repellent protective film, it is effective to cut the C—C bond and C—F bond in the protective film. The method is not particularly limited as long as it can cut the bond, for example, irradiating the wafer surface with light, heating the wafer, exposing the wafer to ozone, irradiating the wafer surface with plasma, For example, corona discharge on the wafer surface may be mentioned.

  When the protective film is removed by light irradiation, wavelengths shorter than 340 nm and 240 nm, which are energy equivalent to 83 kcal / mol and 116 kcal / mol, which are binding energies of C—C bonds and C—F bonds in the protective film. It is preferable to irradiate ultraviolet rays containing. 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.

  Further, when the protective film is removed by light irradiation, if the constituent components of the protective film are decomposed by ultraviolet rays and ozone is generated at the same time and the constituent components of the protective film are oxidized and volatilized by the ozone, the processing time is shortened. Therefore, it is particularly preferable. As this light source, a low-pressure mercury lamp, an excimer lamp, or the like may be used. Further, the wafer may be heated while irradiating light.

  When the wafer is heated, the 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 process, ozone exposure, plasma irradiation, corona discharge, etc. may be used in combination. Further, light irradiation may be performed while heating the wafer.

  Methods for removing the protective film by heating include a method of bringing a wafer into contact with a heat source and a method of placing the wafer in a heated atmosphere such as a heat treatment furnace. The method of placing the wafer in a heated atmosphere is easy to operate because it is easy to uniformly apply energy for removing the protective film to the wafer surface even when processing a plurality of wafers. This is an industrially advantageous method that requires a short processing time and a high processing capacity.

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

  By combining the light irradiation, heating, ozone exposure, plasma irradiation, and corona discharge, the protective film on the wafer surface can be efficiently removed.

Forming a concavo-convex pattern on the surface of a wafer and replacing the cleaning liquid held in at least the concave part of the concavo-convex pattern with other cleaning liquids are techniques already established through various studies in other literature. Therefore, in the present invention, the evaluation was mainly performed on the protective film forming chemical solution. Also, the following formula
P = 2 × γ × cos θ / S
(Wherein γ is the surface tension of the liquid held in the recess, θ is the contact angle between the recess surface and the liquid held in the recess, and S is the width of the recess.)
As can be seen from the above, the pattern collapse greatly depends on the contact angle of the cleaning liquid to the 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 of the concave / convex pattern, the contact angle of the droplet and the capillary force acting on the concave portion, which may be considered equivalent to the pattern collapse, have a correlation. Capillary force may be derived from the evaluation of the contact angle of the drop. In the examples, water was used as the cleaning liquid.

  However, in the case of a wafer having a fine uneven pattern on the surface, the contact angle of the protective film 10 itself formed on the surface of the uneven pattern cannot be accurately evaluated.

  As described in JIS R 3257 “Test method for wettability of substrate glass surface”, water droplet contact angle is evaluated by dropping several μl of water droplets on the surface of the sample (substrate) and measuring the angle between the water droplet and the substrate surface. Made by measurement. However, in the case of a 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 this embodiment, the chemical solution is applied to a wafer having a smooth surface, a protective film is formed on the wafer surface, and the protective film is formed on the surface of the wafer 1 on which the uneven pattern 2 is formed. The film 10 was considered and various evaluations were performed. In this example, a wafer with a titanium nitride film having a titanium nitride layer on a silicon wafer with a smooth surface (hereinafter sometimes referred to as “TiN wafer”) was used as the wafer with a smooth surface.

  Details are described below. In the following, a method for evaluating a wafer cleaned using the water-repellent protective film-forming chemical solution of the present invention, preparation of the protective film-forming chemical solution, and evaluation of a wafer cleaned using the water-repellent protective film-forming chemical solution of the present invention Results are stated.

[Evaluation Method for Wafer Washed Using Water Repellent Protective Film Forming Chemical Solution of the Present Invention]
The following evaluations (1) to (4) were performed as evaluation methods for wafers cleaned using the water-repellent protective film-forming chemical solution of the present invention.

(1) Contact angle evaluation of the protective film formed on the wafer surface About 2 μl of pure water is placed on the surface of the wafer on which the protective film is formed, and the angle (contact angle) formed between the water droplet and the wafer surface is measured by a contact angle meter (Kyowa). It was measured by Interface Science: CA-X type). Here, the protective film having a contact angle in the range of 50 to 130 ° was regarded as acceptable.

(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
(Wherein γ is the surface tension of the liquid held in the recess, θ is the contact angle between the recess surface and the liquid held in the recess, and S is the width of the recess.)
In the present embodiment, as an example of the pattern shape, a line-and-space pattern wafer having a line width (recessed portion width) of 45 nm is assumed. In the pattern with a line width of 45 nm, when the gas-liquid interface passes through the pattern on the wafer surface, the pattern tends to collapse when the liquid is water, and the pattern does not easily collapse when the liquid is 2-propanol. When the wafer surface is, for example, titanium nitride, the contact angle of 2-propanol with the surface is 0.5 °, and the contact angle of water is 2 °. The same applies to other metal substances (titanium, tungsten, aluminum, copper, tin, tantalum nitride, ruthenium, etc.). In the case of the above conditions, when the cleaning liquid is 2-propanol (surface tension: 22 mN / m), the capillary force is 0.98 MN / m ² . On the other hand, the capillary force is 3.2 MN / m ^{2 in} water (surface tension: 72 mN / m) having the largest surface tension among liquids excluding mercury. Therefore, the target was 2.1 MN / m ^{2 in the} middle, and the test was accepted if the capillary force when water was retained was 2.1 MN / m ² or less.

(3) Removability of protective film The sample was irradiated with UV light from a low-pressure mercury lamp for 1 minute under the following conditions. When the contact angle of water droplets was 10 ° or less after irradiation, it was judged that the protective film was removed, and the result was accepted.
・ Lamp: Sen Special Light Source PL2003N-10
Illuminance: 15 mW / cm ² (distance from light source to sample is 10 mm)

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。 (4) Evaluation of surface smoothness of wafer after removal of protective film Surface observation with an atomic force electron microscope (Seiko-Electronics: SPI3700, 2.5 μm square scan) and surface centerline average surface roughness before and after wafer cleaning: The difference ΔRa (nm) of 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.

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.

  The Ra value of the wafer surface before forming the protective film and the Ra value of the wafer surface after removing the protective film are measured. If the difference (ΔRa) is within ± 1 nm, the wafer surface is eroded by cleaning. It was determined that there was no residue of the chemical solution on the wafer surface, and the test was accepted.

[Example 1]
(1) Preparation of water repellent protective film-forming chemical solution Nonafluorohexyldimethylchlorosilane [C ₄ F ₉ (CH ₂ ) ₂ (CH ₃ ) ₂ SiCl] as a water repellent protective film forming agent; 10 g, hydrofluoroether ( 3M HFE-7100); 90 g was mixed and stirred for about 5 minutes, and the concentration of the protective film forming agent relative to the total amount of the protective film forming chemical (hereinafter referred to as “protective film forming agent concentration”) was 10% by mass. A protective film forming chemical was obtained.

(2) Cleaning of TiN wafer A smooth TiN wafer (a silicon wafer having a titanium nitride layer with a thickness of 50 nm on the surface) is immersed in a 1% by mass hydrofluoric acid aqueous solution for 1 minute, and then washed with pure water as an aqueous cleaning solution cleaning step. Immerse for a minute. Thereafter, the wafer was immersed in 2-propanol (hereinafter sometimes referred to as “iPA”) for 1 minute, and then immersed in propylene glycol monomethyl ether acetate (hereinafter sometimes referred to as “PGMEA”) for 1 minute. did.

(3) Surface treatment of wafer surface with water-repellent cleaning solution The TiN wafer after “(2) Cleaning of TiN wafer” is applied to the protective film forming chemical solution prepared in the above “(1) Preparation of protective film forming chemical solution” at 20 ° C. Soaked for 1 minute. Thereafter, the TiN wafer was immersed in iPA for 10 seconds. Finally, the TiN wafer was taken out from the iPA and air was blown to remove the surface iPA.

When the obtained TiN wafer was evaluated in the manner described in the above-mentioned “Evaluation Method of Wafer Washed Using Water-Repellent Protective Film Forming Chemical Solution of the Present Invention”, as shown in Table 1, before forming the water-repellent protective film. Although the initial contact angle was less than 10 °, the contact angle after forming the protective film was 91 °, indicating an excellent water repellency imparting effect. Further, when the capillary force when water was retained was calculated using the formula described in the above “Evaluation of Capillary Force”, the capillary force was 0.06 MN / m ² and the capillary force was small. Moreover, the contact angle after UV irradiation was less than 10 °, and the protective film could be removed. Further, the ΔRa value of the wafer by UV irradiation was within ± 0.5 nm, and it was confirmed that the wafer was not eroded during cleaning, and that no protective film residue remained after UV irradiation.

[Examples 2 to 4]
The protective film forming agent, the organic solvent, the protective film forming agent concentration, the catalyst, and the protective film forming process time used in Example 1 were appropriately changed to perform surface treatment of the wafer, and further evaluated. The results are shown in Table 1. The catalyst concentration is a concentration by mass relative to 100% by mass of the total amount of the protective film forming agent.

[Comparative Example 1]
The same as Example 1 except that the protective film forming chemical solution was a mixture of N, N-dimethylaminotrimethylsilane [(CH ₃ ) ₃ SiN (CH ₃ ) ₂ ]; 10 g, PGMEA; 90 g. . As a result, as shown in Table 1, the contact angle of the TiN wafer was 18 °, and the effect of imparting water repellency was not obtained. Further, when the capillary force when water was retained was calculated using the formula described in the above “Evaluation of Capillary Force”, the capillary force was 3.0 MN / m ² and the capillary force was large.

DESCRIPTION OF SYMBOLS 1 Wafer 2 Convex / concave pattern on wafer surface 3 Convex part 4 Pattern concave part 5 Concave width 6 Convex height 7 Convex width 8 Water repellent protective film forming chemical 9 held in concave part 4 Retained in concave part 4 Liquid 10 water repellent protective film

Claims (9)

At least one substance selected from the group consisting of titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium, in which at least a part of the concave surface of the concave / convex pattern is a wafer having a concave / convex pattern formed on the surface Is a water-repellent protective film-forming chemical solution containing a water-repellent protective film-forming agent for forming a water-repellent protective film on at least the concave surface of the wafer, and the water-repellent protective film-forming agent is A water repellent protective film-forming chemical, which is a silicon compound represented by the general formula [1].
R ¹ _a R ² _b SiX _4-a-b [1]
[In the formula [1], R ^{1 s} are each independently a hydrocarbon group in which one or more hydrogen elements having 1 to 18 carbon atoms are substituted with fluorine elements, and R ² are each independently A hydrogen group or a hydrocarbon group having 1 to 18 carbon atoms, the total number of carbon atoms contained in R ¹ and R ² in the formula [1] is 6 or more, and X is independently of each other. And at least one group selected from the group consisting of a monovalent functional group in which the element bonded to the silicon element is nitrogen, a monovalent functional group in which the element bonded to the silicon element is oxygen, and a halogen group. Moreover, a is an integer of 1-3, b is an integer of 0-2, and the sum total of a and b is 1-3. ] The water-repellent protective film-forming chemical solution according to claim 1, wherein the water-repellent protective film-forming agent is a silicon compound represented by the following general formula [2].
R ¹ _a R ² _b SiX [2]
[In the formula [2], R ¹ are each independently a hydrocarbon group in which at least one hydrogen element having 1 to 18 carbon atoms is substituted with a fluorine element, and R ² are each independently , A hydrogen group, or a hydrocarbon group having 1 to 18 carbon atoms, the total number of carbon atoms contained in R ¹ and R ² in the formula [2] is 6 or more, and X is bonded to a silicon element. A monovalent functional group in which the element to be bonded is nitrogen, a monovalent functional group in which the element bonded to the silicon element is oxygen, or a halogen group. A is an integer of 1 to 3, b is an integer of 0 to 2, and the sum of a and b is 3. ] The water-repellent protective film-forming chemical solution according to claim 1 or 2, wherein the water-repellent protective film-forming agent is a silicon compound represented by the following general formula [3].
R ³ (CH ₃ ) ₂ SiX [3]
[In the formula [3], R ³ is a hydrocarbon group in which one or more hydrogen elements having 4 to 18 carbon atoms are substituted with fluorine elements, and X is a monovalent element in which the element bonded to the silicon element is nitrogen. A functional group, a monovalent functional group in which the element bonded to the silicon element is oxygen, or a halogen group. ] The water repellent protective film-forming chemical solution according to any one of claims 1 to 3, wherein R ¹ or R ³ in the silicon compound contains 5 or more fluorine atoms. 5. The water-repellent protective film-forming chemical solution according to claim 1, further comprising a solvent. 6. The water-repellent protective film-forming chemical solution according to any one of claims 1 to 5, comprising an acid. The water-repellent protective film forming agent is mixed so as to be 0.1 to 50% by mass with respect to 100% by mass of the total amount of the water-repellent protective film-forming chemical solution. Item 7. The water-repellent protective film-forming chemical solution according to any one of Items 6. At least one substance selected from the group consisting of titanium, titanium nitride, tungsten, aluminum, copper, tin, tantalum nitride, and ruthenium, in which at least a part of the concave surface of the concave / convex pattern is a wafer having a concave / convex pattern formed on the surface A method for cleaning a wafer including
A water-based cleaning liquid cleaning step for cleaning the wafer surface with a water-based cleaning liquid. A water-repellent protective film-forming chemical solution containing a water-repellent protective film-forming agent for forming a water-repellent protective film on the wafer surface is formed in at least the recesses of the wafer. Holding and forming a water repellent protective film on the surface of the recess, removing the liquid on the wafer surface, removing the liquid on the wafer surface, removing the water repellent protective film from the surface of the recess, and removing the water repellent protective film A method for cleaning a wafer, comprising using the chemical solution for forming a water-repellent protective film according to claim 1 in the step of forming a water-repellent protective film. In the water repellent protective film removing step, the water repellent protective film is at least selected from the group consisting of irradiating the wafer surface with light, heating the wafer, exposing the wafer to ozone, and irradiating the wafer with plasma. The cleaning method according to claim 8, wherein the cleaning method is performed by one processing method.

Images