Chemical solution for forming water-repellent protective film, method for preparing the same, and method for producing surface-treated body

Abstract

The present invention provides a novel chemical solution for forming a water-repellent protective film, which contains a novel catalytic component having various basicities, a method for preparing the same, and a method for manufacturing a surface-treated body using the chemical solution. The chemical solution for forming a water-repellent protective film of the present invention is a chemical solution for forming a water-repellent protective film for forming a water-repellent protective film on a surface of a wafer, wherein the surface of the wafer contains silicon, and the chemical solution for forming a water-repellent protective film contains: (I) a silylating agent, (II) at least one nitrogen-containing compound among the compounds represented by the following general formulas [1] and [2], and (III) an organic solvent.

Description

Technical Field

[0001] The present invention relates to a chemical solution for forming a water-repellent protective film for forming a water-repellent protective film on a wafer surface, a method for preparing the chemical solution, and a method for producing a surface-treated body using the chemical solution. Background Art

[0002] For semiconductor devices used in networks and digital home appliances, further high performance / high functionality and low power consumption are required. Therefore, the miniaturization of circuit patterns is advancing, and with the advancement of miniaturization, the pattern collapse of circuit patterns has become a problem. In the manufacture of semiconductor devices, a cleaning process is often used to remove particles and metal impurities. As a result, the cleaning process accounts for as much as 30% to 40% of the entire semiconductor manufacturing process. In this cleaning process, if the aspect ratio of the pattern accompanying the miniaturization of the semiconductor device becomes higher, the phenomenon of pattern collapse when the gas-liquid interface passes through the pattern after cleaning or rinsing is called pattern collapse. In order to prevent the occurrence of pattern collapse, the design of the pattern has to be changed, or the yield rate during production is reduced. Therefore, a method for preventing pattern collapse in the cleaning process is desired.

[0003] As a method for preventing pattern collapse, it is known that forming a water-repellent protective film on the pattern surface is effective. The water repellency needs to be carried out without drying the pattern surface, so the water-repellent protective film is formed by replacing the cleaning liquid with a water-repellent protective film forming chemical solution that can make the pattern surface water-repellent.

[0004] For example, in Patent Document 1, as a surface treatment agent that can effectively prevent the pattern collapse of an inorganic pattern or a resin pattern set on a substrate, a surface treatment agent for surface treatment of a treated body is disclosed, which comprises: a silylating agent; and a nitrogen-containing heterocyclic compound that does not contain silicon atoms and serves as a catalyst for promoting the reaction of the silylating agent.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-063179 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] The patterns of semiconductor wafers are composed of various raw materials (films), and the types of such films have tended to increase in recent years. Based on this situation, depending on the acidity / alkalinity of the catalytic component contained in the processing liquid for preventing the pattern collapse of the wafer, there may be a compatibility problem that the surface treatment cannot be applied to the wafer having a specific film type.

[0010] In the surface treatment agent described in Patent Document 1, a nitrogen-containing heterocyclic compound that does not contain a silicon atom is used as a catalyst of various acidities / alkalinities for promoting the reaction of a silylating agent. However, as mentioned above, in order to be applied to a combination of film types that is expected to increase significantly in the future, it is desired to ensure the selection of a wider variety of chemical solutions, and a treatment solution containing a new catalytic component having various acidities / alkalinities is sought.

[0011] Therefore, the object of the present invention is to provide a novel chemical solution for forming a water-repellent protective film (hereinafter sometimes abbreviated as "chemical solution for forming a protective film", "chemical solution") containing a new catalytic component having various basicities, a preparation method thereof, and a method for manufacturing a surface-treated body using the chemical solution.

[0012] Solutions for solving problems

[0013] The present invention is a chemical solution for forming a water-repellent protective film, which is used to form a water-repellent protective film on the surface of a wafer, wherein the surface of the wafer contains silicon element, and the chemical solution for forming a water-repellent protective film contains:

[0014] (I) a silylating agent,

[0015] (II) at least one nitrogen-containing compound among the compounds represented by the following general formulas [1] and [2], and

[0016] (III) Organic solvents.

[0017]

[0018]

[0019] [In formulas [1] and [2], R 1 Each of them is independently selected from a hydrogen atom, a -C≡N group, a -NO2 group, and a hydrocarbon group in which a part or all of the hydrogen elements are optionally replaced by fluorine elements, wherein the hydrocarbon group optionally contains oxygen atoms and / or nitrogen atoms, and when containing nitrogen atoms, it presents a non-cyclic structure. 2 Selected from hydrogen atoms, -C≡N groups, -NO2 groups, alkylsilyl groups, and hydrocarbon groups in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, wherein the hydrocarbon groups optionally have oxygen atoms and / or nitrogen atoms, and when nitrogen atoms are included, the hydrocarbon groups present a non-cyclic structure.]

[0020] From the viewpoint of cleanliness of the chemical solution, it is preferred that the above-mentioned (II) is a liquid at 25° C. and 1.0 atm.

[0021] From the viewpoint of the effect of imparting water repellency, it is preferred that the silylating agent is at least one selected from the group consisting of compounds represented by the following general formulas [3] to [6].

[0022] (R 3 ) a (H) b Si〔OC(=O)R 4 〕 4-a-b [3]

[0023] In formula [3], R 3 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally substituted with fluorine elements, R 4 Each is independently selected from an alkyl group having 1 to 6 carbon atoms in which a part or all of the hydrogen elements are optionally substituted with fluorine elements. a is an integer of 1 to 3, b is an integer of 0 to 2, and the total of a and b is 3 or less.]

[0024] (R 5 ) c (H) d Si〔N(R 6 )C(=O)R 7 〕 4-c-b [4]

[0025] In formula [4], R 5 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally substituted with fluorine elements, R 6 are each independently a group selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 6 carbon atoms in which a part or all of the hydrogen atoms are optionally substituted with fluorine atoms, and R 7 They are independently selected from an alkyl group having 1 to 6 carbon atoms in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, c is an integer of 1 to 3, d is an integer of 0 to 2, and the total of c and d is 3 or less.]

[0026] (R 8 ) e (H) f SiN=C(R 9 )OSi(H) g (R 10 ) h [5]

[0027] In formula [5], R 8 and R 10 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally substituted with fluorine elements, R 9It is a group selected from the group consisting of hydrogen atoms and alkyl groups having 1 to 6 carbon atoms in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, e and h are integers of 1 to 3, f and g are integers of 0 to 2, and the total of e and f and the total of g and h are both 3.]

[0028] (R 11 ) i (H) j Si-Y [6]

[0029] In formula [6], R 11 Each is independently selected from a monovalent hydrocarbon group having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally substituted with fluorine elements. i is an integer of 1 to 3, j is an integer of 0 to 2, and the sum of i and j is 3. Y represents a monovalent nitrogen-containing heterocyclic group optionally having a substituent.]

[0030] From the viewpoint of the effect of imparting water repellency, it is preferred that the silylating agent further contains at least one selected from the group consisting of compounds represented by the following general formula [7].

[0031] 〔(R 12 ) k (H) l Si〕2NH [7]

[0032] In formula [7], R 12 Each of them is independently selected from a monovalent hydrocarbon group having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally replaced by fluorine elements. k is an integer of 1 to 3, l is an integer of 0 to 2, and the total of k and l is 3.]

[0033] When the concentration of (II) is 0.01 to 30% by mass relative to 100% by mass of the total amount of (I) to (III), it is preferable because a protective film can be easily formed uniformly on the surface of a wafer containing silicon element.

[0034] From the viewpoint of imparting water repellency, it is preferred that R in the general formulas [1] and [2] 1 are each independently a group selected from a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms, and R 2 It is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkylsilyl group represented by the following general formula [8].

[0035] -〔Si(R 13 ) m (H) n 〕 [8]

[0036] [R 13They are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms, m and n are integers of 0 to 3, and the total of m and n is 3.]

[0037] From the viewpoint of the effect of imparting water repellency, it is preferred that the above-mentioned (II) is at least one nitrogen-containing compound among the compounds represented by the above-mentioned general formula [1].

[0038] In addition, when a of the general formula [3], c of the general formula [4], e and h of the general formula [5], and i of the general formula [6] are 3, water repellency can be easily maintained during cleaning after forming a protective film as described below. In addition, when the general formula [7] is further included, when k is 3, water repellency can be easily maintained during cleaning after forming a protective film as described below.

[0039] In addition, if R in the above general formula [3] 3 At least two of them are methyl groups, and R 5 At least two of them are methyl groups, and R 8 At least two of them are methyl groups, R 10 At least two of them are methyl groups, and R 11 At least two of them are methyl groups, because the protective film can be formed homogeneously, which is more preferred. In addition, when the above general formula [7] is further included, if R 12 It is more preferred that at least two of them are methyl groups because the protective film can be formed homogeneously.

[0040] In addition, when the concentration of (I) is 1 to 50% by mass relative to 100% by mass of the total amount of (I) to (III), it is preferable because a protective film can be easily formed uniformly on the surface of a wafer containing silicon element.

[0041] Furthermore, from the viewpoint of chemical solution stability, it is preferred that the organic solvent (III) is an aprotic solvent.

[0042] In addition, the present invention is a method for preparing a chemical solution for forming a water-repellent protective film, wherein the chemical solution for forming a water-repellent protective film is used to form a water-repellent protective film on a surface of a wafer, wherein the surface of the wafer contains silicon.

[0043] In the method, at least (I) a silylating agent, (II) at least one nitrogen-containing compound represented by the following general formulas [1] and [2], and (III) an organic solvent are mixed under the conditions of 15 to 35° C. and 0.5 to 1.5 atmospheres to prepare a chemical solution for forming a water-repellent protective film containing the above (I) to (III) in a solution state.

[0044]

[0045] [In formulas [1] and [2], R 1 Each of them is independently selected from a hydrogen atom, a -C≡N group, a -NO2 group, and a hydrocarbon group in which a part or all of the hydrogen elements are optionally replaced by fluorine elements, wherein the hydrocarbon group optionally contains oxygen atoms and / or nitrogen atoms, and when containing nitrogen atoms, it presents a non-cyclic structure. 2 Selected from hydrogen atoms, -C≡N groups, -NO2 groups, alkylsilyl groups, and hydrocarbon groups in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, wherein the hydrocarbon groups optionally have oxygen atoms and / or nitrogen atoms, and when nitrogen atoms are included, the hydrocarbon groups present a non-cyclic structure.]

[0046] It should be noted that, from the viewpoint of preventing the chemical solution from deteriorating, the preparation of the chemical solution for forming a water-repellent protective film is preferably carried out in an inert gas atmosphere such as nitrogen or argon. At this time, the gas pressure is preferably 0.5 to 1.5 atmospheres, and more preferably 1.0 to 1.5 atmospheres.

[0047] The present invention is also a method for producing a surface-treated body, comprising treating the surface of a body to be treated by bringing any of the above-mentioned chemical solutions for forming a water-repellent protective film into contact with the surface of the body to be treated.

[0048] Effects of the Invention

[0049] The chemical solution for forming a water-repellent protective film of the present invention can exert excellent water repellency imparting effect and excellent solubility of raw materials in a good balance. By using the chemical solution for forming a water-repellent protective film of the present invention, new options for chemical solutions for forming a water-repellent protective film can be ensured to cope with the various combinations of semiconductor wafer structures that will continue to increase in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a schematic perspective view of a wafer 1 having a surface having a fine concavo-convex pattern 2 on its surface.

[0051] Figure 2 It is shown Figure 1 A diagram of a portion of the a-a' section.

[0052] Figure 3 This is a schematic diagram showing a state in which the protective film forming chemical solution 8 is retained in the concave portion 4 during the cleaning step.

[0053] Figure 4 This is a schematic diagram showing a state in which the recessed portion 4 formed with the protective film holds a liquid. DETAILED DESCRIPTION

[0054] 1. Chemical solutions for forming water-repellent protective films

[0055] The water-repellent protective film-forming liquid chemical of the present invention is a solution containing (I) a silylating agent, (II) at least one nitrogen-containing compound among the compounds represented by the general formulas [1] and [2], and (III) an organic solvent.

[0056] About (I) Silylating Agent

[0057] The silylating agent of the chemical solution for forming the water-repellent protective film of the present invention is not particularly limited, and a known silylating agent can be used. The above-mentioned silylating agent reacts with the surface of the wafer containing the silicon element to form a water-repellent protective film on the surface. It should be noted that the water-repellent protective film can be formed by the above-mentioned silylating agent, and can also contain a reactant with the silylating agent as the main component.

[0058] From the viewpoint of imparting water repellency, it is preferred that the silylating agent is at least one selected from the group consisting of compounds represented by the general formulas [3] to [6].

[0059] Specific examples of the silylating agent represented by the general formula [3] include CH3Si〔OC(=O)CF3〕3, C2H5Si〔OC(=O)CF3〕3, C3H7Si〔OC(=O)CF3〕3, C4H9Si〔OC(=O)CF3〕3, C5H 11 Si〔OC(=O)CF3〕3、C6H 13 Si〔OC(=O)CF3〕3、C7H 15 Si〔OC(=O)CF3〕3、C8H 17 Si〔OC(=O)CF3〕3、C9H 19 Si〔OC(=O)CF3〕3、C 10 H 21 Si〔OC(=O)CF3〕3、C 11 H 23 Si〔OC(=O)CF3〕3、C 12 H 25 Si〔OC(=O)CF3〕3、C 13 H 27 Si〔OC(=O)CF3〕3、C 14 H 29 Si〔OC(=O)CF3〕3、C 15 H 31 Si〔OC(=O)CF3〕3、C 16 H 33 Si〔OC(=O)CF3〕3、C 17H 35 If〔OC(=O)CF3〕3、C 18 H 37 Si〔OC(=O)CF3〕3、(CH3)2Si〔OC(=O)CF3〕2、C2H5Si(CH3)〔OC(=O)CF3〕2、(C2H5)2Si〔OC(=O)CF3〕2、C3H7Si (CH3)〔OC(=O)CF3〕2、(C3H7)2Si〔OC(=O)CF3〕2、C4H9Si(CH3)〔OC(=O)CF3〕2、(C4H9)2Si〔OC(=O)CF3〕2、C5H 11 Si(CH3)〔OC(=O)CF3〕2、C6H 13 Si(CH3)〔OC(=O)CF3〕2、C7H 15 Si(CH3)〔OC(=O)CF3〕2、C8H 17 Si(CH3)〔OC(=O)CF3〕2、C9H 19 Si(CH3)〔OC(=O)CF3〕2、C 10 H 21 Si(CH3)〔OC(=O)CF3〕2、C 11 H 23 Si(CH3)〔OC(=O)CF3〕2、C 12 H 25 Si(CH3)〔OC(=O)CF3〕2、C 13 H 27 Si(CH3)〔OC(=O)CF3〕2、C 14 H 29 Si(CH3)〔OC(=O)CF3〕2、C 15 H 31 Si(CH3)〔OC(=O)CF3〕2、C 16 H 33 Si(CH3)〔OC(=O)CF3〕2、C 17 H 35 Si(CH3)〔OC(=O)CF3〕2、C 18 H 37Si(CH3)〔OC(=O)CF3〕2、(CH3)3SiOC(=O)CF3、C2H5Si(CH3)2OC(=O)CF3、(C2H5)2Si(CH3)OC(=O)CF3、(C2H5)3SiOC(=O)CF3、C3H5 7Si(CH3)2OC(=O)CF3、(C3H7)2Si(CH3)OC(=O)CF3、(C3H7)3SiOC(=O)CF3、C4H9Si(CH3)2OC(=O)CF3、(C4H9)3SiOC(=O)CF3、C5H9 11 Si(CH3)2OC(=O)CF3、C6H 13 Si(CH3)2OC(=O)CF3、C7H 15 Si(CH3)2OC(=O)CF3、C8H 17 Si(CH3)2OC(=O)CF3、C9H 19 Si(CH3)2OC(=O)CF3、C 10 H 21 Si(CH3)2OC(=O)CF3、C 11 H 23 Si(CH3)2OC(=O)CF3、C 12 H 25 Si(CH3)2OC(=O)CF3、C 13 H 27 Si(CH3)2OC(=O)CF3、C 14 H 29 Si(CH3)2OC(=O)CF3、C 15 H 31 Si(CH3)2OC(=O)CF3、C 16 H 33 Si(CH3)2OC(=O)CF3、C 17 H 35 Si(CH3)2OC(=O)CF3、C 18 H 37<h2 style=";text-align:left;direction:ltr">Si(CH3)2OC(=O)CF3、(CH3)2Si(H)OC(=O)CF3、CH3Si(H)2OC(=O)CF3、(C2H5)2Si(H)OC(=O)CF3、C2H5Si(H)2OC(=O)CF3、C2H5Si(CH3)(H)OC(=O)CF3、(C3H7)2Si( H)OC(=O)CF3、C3H7Si(H)2OC(=O)CF3、CF3CH2CH2Si〔OC(=O)CF3〕3、C2F5CH2CH2S i〔OC(=O)CF3〕3、C3F7CH2CH2Si〔OC(=O)CF3〕3、C4F9CH2CH2Si〔OC(=O)CF3〕3、C5F<h2 style=";text-align:left;direction:ltr"> 11 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si〔OC(=O)CF3〕3、C6F<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si〔OC(=O)CF3〕3、C7F<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si〔OC(=O)CF3〕3、C8F<h2 style=";text-align:left;direction:ltr"> 17 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si〔OC(=O)CF3〕3、CF3CH2CH2Si(CH3)〔OC(=O)CF3〕2、C2F5CH2CH2Si(CH3)〔OC(=O)CF3〕2、C3F7CH2CH2Si(CH3)〔OC(=O)CF3〕2、C4F9CH2CH2Si(CH3)〔OC(=O)CF3〕2、C5F<h2 style=";text-align:left;direction:ltr"> 11 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)〔OC(=O)CF3〕2、C6F<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)〔OC(=O)CF3〕2、C7F<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)〔OC(=O)CF3〕2、C8F<h2 style=";text-align:left;direction:ltr"> 17 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)OC(=O)CF3〕2, CF3CH2CH2Si(CH3)2OC(=O)CF3, C2F5CH2CH2Si(CH3)2OC(=O)CF3, C3F7CH2CH2Si(CH3)2OC(=O)CF3, C4F9CH2CH2Si(CH3)2OC(=O)CF3, C5F<h2 style=";text-align:left;direction:ltr"> 11 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)2OC(=O)CF3、C6F<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)2OC(=O)CF3,C7F<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)2OC(=O)CF3、C8F<h2 style=";text-align:left;direction:ltr"> 17trifluoroacetoxysilanes such as CH2CH2Si(CH3)2OC(=O)CF3, CF3CH2CH2Si(CH3)(H)OC(=O)CF3; or the -OC(=O)CF3 group of the above trifluoroacetoxysilane is replaced by -OC(=O)R 4 (R 4 A group obtained by using an alkyl group having 1 to 6 carbon atoms in which a part or all of the hydrogen elements are optionally substituted by fluorine elements.

[0060] From the viewpoint of imparting water repellency, the above-mentioned -OCOR 4 Base R 4 An alkyl group in which all hydrogen elements are substituted with fluorine elements is preferred, and the number of carbon atoms in the alkyl group is more preferably 1 to 4, and the number of carbon atoms is particularly preferably 1.

[0061] In addition, if -OC(=O)R represented by 4-ab in the general formula [3] 4 The number of the groups is preferably 1, because the protective film can be formed homogeneously.

[0062] In addition, when b in the general formula [3] is 0, water repellency can be easily maintained in the cleaning after the formation of the protective film described later, which is preferred.

[0063] Furthermore, if the above R 3 A combination of two -CH 3 groups and one linear alkyl group is more preferred because the protective film can be formed homogeneously.

[0064] Specific examples of the silylating agent represented by the general formula [4] include CH3Si〔N(CH3)C(=O)CF3〕3, C2H5Si〔N(CH3)C(=O)CF3〕3, C3H7Si〔N(CH3)C(=O)CF3〕3, C4H9Si〔N(CH3)C(=O)CF3〕3, C5H 11 Si[N(CH3)C(=O)CF3]3, C6H 13 Si[N(CH3)C(=O)CF3]3, C7H 15 Si[N(CH3)C(=O)CF3]3, C8H 17 Si[N(CH3)C(=O)CF3]3, C9H 19 Si〔N(CH3)C(=O)CF3〕3、C 10 H 21 Si〔N(CH3)C(=O)CF3〕3、C 11 H 23 Si〔N(CH3)C(=O)CF3〕3、C 12 H25 If〔N(CH3)C(=O)CF3〕3、C 13 H 27 If〔N(CH3)C(=O)CF3〕3、C 14 H 29 If〔N(CH3)C(=O)CF3〕3、C 15 H 31 If〔N(CH3)C(=O)CF3〕3、C 16 H 33 If〔N(CH3)C(=O)CF3〕3、C 17 H 35 If〔N(CH3)C(=O)CF3〕3、C 18 H 37 Si〔N(CH3)C(=O)CF3〕3、(CH3)2Si〔N(CH3)C(=O)CF3〕2、C2H5Si(CH3)〔N(CH3)C(=O)CF3〕2、(C2H5)2Si〔N(CH3)C(=O)CF3〕2、C3H7Si(CH3)〔N(CH3)C(=O)CF3〕2、(C3H7)2Si〔N(CH3)C(=O)CF3〕2、C4H9Si(CH3)〔N(CH3)C(=O)CF3〕2、(C4H9)2Si〔N(CH3)C(=O)CF3〕2、C5H 11 Si(CH3)〔N(CH3)C(=O)CF3〕2、C6H 13 Si(CH3)〔N(CH3)C(=O)CF3〕2、C7H 15 Si(CH3)〔N(CH3)C(=O)CF3〕2、C8H 17 Si(CH3)〔N(CH3)C(=O)CF3〕2、C9H 19 Si(CH3)〔N(CH3)C(=O)CF3〕2、C 10 H 21 Si(CH3)〔N(CH3)C(=O)CF3〕2、C 11 H 23 Si(CH3)〔N(CH3)C(=O)CF3〕2、C 12 H 25 Si(CH3)〔N(CH3)C(=O)CF3〕2、C 13 H 27 Si(CH3)〔N(CH3)C(=O)CF3〕2、C 14 H 29 Si(CH3)〔N(CH3)C(=O)CF3〕2、C 15 H<h2 style=";text-align:left;direction:ltr"> 31 <h2 style=";text-align:left;direction:ltr"> Si(CH3)〔N(CH3)C(=O)CF3〕2、C<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 33 <h2 style=";text-align:left;direction:ltr"> Si(CH3)〔N(CH3)C(=O)CF3〕2、C<h2 style=";text-align:left;direction:ltr"> 17 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 35 <h2 style=";text-align:left;direction:ltr"> Si(CH3)〔N(CH3)C(=O)CF3〕2、C<h2 style=";text-align:left;direction:ltr"> 18 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 37 <h2 style=";text-align:left;direction:ltr"> Si(CH3)N(CH3)C(=O)CF3〕2、(CH3)3SiN(CH3)C(=O)CF3、C2H5Si(CH3)2N(CH3)C(=O)CF3、(C2H5)2Si(CH3)N(CH3)C(=O)CF3、(C2H5)3SiN(CH3)C(=O)CF3、C3H 7Si(CH3)2N(CH3)C(=O)CF3, (C3H7)2Si(CH3)N(CH3)C(=O)CF3, (C3H7)3SiN(CH3)C(=O)CF3, C4H9Si(CH3)2N(CH3)C(=O)CF3, (C4H9)3SiN(CH3)C(=O)CF3, C5H<h2 style=";text-align:left;direction:ltr"> 11 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(O)CF3,C6H<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3,C7H<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3,C8H<h2 style=";text-align:left;direction:ltr"> 17 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3,C9H<h2 style=";text-align:left;direction:ltr"> 19 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3、C<h2 style=";text-align:left;direction:ltr"> 10 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 21 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3、C<h2 style=";text-align:left;direction:ltr"> 11 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 23 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3、C<h2 style=";text-align:left;direction:ltr"> 12 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 25 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3、C<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 27 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3、C<h2 style=";text-align:left;direction:ltr"> 14 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 29 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3、C<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 31 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3、C<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 33 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3、C<h2 style=";text-align:left;direction:ltr"> 17 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 35 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3、C<h2 style=";text-align:left;direction:ltr"> 18 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 37 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N(CH3)C(=O)CF3、(CH3)2Si(H)N(CH3)C(=O)CF3、CH3Si(H)2N(CH3)C(=O)CF3、(C2H5)2Si(H)N(CH3)C(=O)CF3、C2H5Si(H)2N(CH3)C(=O)CF3、C2H5Si(CH3)(H)N(CH3)C(=O)CF3、(C3H7)2Si( H)N(CH3)C(=O)CF3, C3H7Si(H)2N(CH3)C(=O)CF3, CF3CH2CH2Si, N(CH3)C(=O)CF3, 3, C2F5CH2CH2Si, N(CH3)C(=O)CF3, 3, C3F7CH2CH2Si, N(CH3)C(=O)CF3, 3, C4F9CH2CH2Si, N(CH3)C(=O)CF3, 3, C5F<h2 style=";text-align:left;direction:ltr"> 11 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si〔N(CH3)C(=O)CF3〕3、C6F<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si〔N(CH3)C(=O)CF3〕3、C7F<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si〔N(CH3)C(=O)CF3〕3、C8F<h2 style=";text-align:left;direction:ltr"> 17 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si〔N(CH3)C(=O)CF3〕3、CF3CH2CH2Si(CH3)〔N(CH3)C(=O)CF3〕2、C2F5CH2CH2Si(CH3)〔N(CH3) C(=O)CF3〕2、C3F7CH2CH2Si(CH3)〔N(CH3)C(=O)CF3〕2、C4F9CH2CH2Si(CH3)〔N(CH3)C(=O)CF3〕2、C5F<h2 style=";text-align:left;direction:ltr"> 11 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)〔N(CH3)C(=O)CF3〕2、C6F<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)〔N(CH3)C(=O)CF3〕2、C7F<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)〔N(CH3)C(=O)CF3〕2、C8F<h2 style=";text-align:left;direction:ltr"> 17 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)〔N(CH3)C(=O)CF3〕2、CF3CH2CH2Si(CH3)2N(CH3)C(=O)CF3、C2F5CH2CH2Si(CH3)2N(CH3)C(=O)CF3、C3F7CH2CH2Si(C<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr">

[0065] H3)2N(CH3)C(=O)CF3、C4F9CH2CH2Si(CH3)2N(CH3)C(=O)CF3、C5F 11 CH2CH2Si(CH3)2N(CH3)C(=O)CF3, C6F 13 CH2CH2Si(CH3)2N(CH3)C(=O)CF3、C7F 15 CH2CH2Si(CH3)2N(CH3)C(=O)CF3、C8F 17 N-methyl-N-alkylsilyl trifluoroacetamides such as CH2CH2Si(CH3)2N(CH3)C(=O)CF3, CF3CH2CH2Si(CH3)(H)N(CH3)C(=O)CF3; or the -N(CH3)C(=O)CF3 group of the above-mentioned N-methyl-N-alkylsilyl trifluoroacetamide is replaced by -N(CH3)C(=O)R 7 (R 7 In the example of the above compounds, -N(CH3)C(=O)R 7 A compound obtained by replacing the methyl group with a hydrogen atom, an ethyl group, a propyl group, a butyl group, a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group or the like.

[0066] From the viewpoint of imparting water repellency, the above- 6 )C(=O)R 7 〕Based on R 7 An alkyl group in which all hydrogen elements are substituted with fluorine elements is preferred, and the number of carbon atoms in the alkyl group is more preferably 1 to 4, and the number of carbon atoms is particularly preferably 1.

[0067] In addition, if -[N(R 6 )C(=O)R 7 〕 group is 1, since the protective film can be formed homogeneously, which is more preferred.

[0068] In addition, when d in the general formula [4] is 0, water repellency can be easily maintained in the cleaning after the formation of the protective film described later, which is preferred.

[0069] Furthermore, if the above R 5 A combination of two -CH 3 groups and one linear alkyl group is more preferred because the protective film can be formed homogeneously.

[0070] As specific examples of the silylating agent represented by the above general formula [5], (CH3)3SiN=C(CH3)OSi(CH3)3, C2H5Si(CH3)2N=C(CH3)O(CH3)2SiC2H5, (C2H5)2Si(CH3)N=C(CH3)O(CH3)Si(C2H5)2, (C2H5)3SiN=C(CH3)OSi(C2H5)3, C3H7Si(CH3)2N=C(CH3)O(CH3)2SiC3H7, (C3H7)2Si(CH3)N=C(CH3)O(CH3)Si(C3H7)2, (C3H7)3SiN=C(CH3)OSi(C3H7)3, C4H9Si(CH3)2N=C(CH3)O(CH3)2SiC4H9, (C4H9)3SiN=C(CH3)OSi(C4H9)3, C5H 11 Si(CH3)2N=C(CH3)O(CH3)2SiC5H 11 、C6H 13 Si(CH3)2N=C(CH3)O(CH3)2SiC6H 13 、C7H 15 Si(CH3)2N=C(CH3)O(CH3)2SiC7H 15 、C8H 17 Si(CH3)2N=C(CH3)O(CH3)2SiC8H 17 、C9H 19 Si(CH3)2N=C(CH3)O(CH3)2SiC9H 19 、C 10 H 21 Si(CH3)2N=C(CH3)O(CH3)2SiC 10 H 21 、C 11 H 23 Si(CH3)2N=C(CH3)O(CH3)2SiC 11 H 23 、C 12 H 25 Si(CH3)2N=C(CH3)O(CH3)2SiC 12 H 25 、C 13 H 27 Si(CH3)2N=C(CH3)O(CH3)2SiC 13 H 27 、C 14 H 29 Si(CH3)2N=C(CH3)O(CH3)2SiC 14 H<h2 style=";text-align:left;direction:ltr"> 29 <h2 style=";text-align:left;direction:ltr"> C<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 31 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N = C(CH3)O(CH3)2SiC<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 31 <h2 style=";text-align:left;direction:ltr"> C<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 33 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N = C(CH3)O(CH3)2SiC<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 33 <h2 style=";text-align:left;direction:ltr"> C<h2 style=";text-align:left;direction:ltr"> 17 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 35 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N = C(CH3)O(CH3)2SiC<h2 style=";text-align:left;direction:ltr"> 17 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 35 <h2 style=";text-align:left;direction:ltr"> C<h2 style=";text-align:left;direction:ltr"> 18 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 37 <h2 style=";text-align:left;direction:ltr"> Si(CH3)2N = C(CH3)O(CH3)2SiC<h2 style=";text-align:left;direction:ltr"> 18 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 37 <h2 style=";text-align:left;direction:ltr"> (CH3)2Si(H)N = C(CH3)O(H)Si(CH3)2, CH3Si(H)2N = C(CH3)O(H)2SiCH3, (C2H5)2Si(H)N = C(CH3)O(H)Si(C2H5)2, C2H5Si(H)2N = C(CH3)O(H)2SiC2H5, C2H5Si(CH3)(H)N = C(CH3)O(CH3)(H)SiC2H5, (C3H7)2Si(H)N = C(CH3)O(H)Si(C3H7)2, C3H7Si(H) 2N = C(CH3)O(H)2SiC3H7, CF3CH2CH2Si(CH3)2N = C(CH3)O(CH3)2SiCH2CH2CF3, C2F5CH2CH2Si(CH3)2N = C(CH3)O(CH3)2SiCH2CH2C2F5, C3F7CH2CH2Si(CH3)2N = C(CH3)O(CH3)2SiCH2CH2C3F7, C4F9CH2CH2Si(CH3)2N = C(CH3)O(CH3)2SiCH2CH2C4F9, C5F<h2 style=";text-align:left;direction:ltr"> 11 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)2N = C(CH3)O(CH3)2SiCH2CH2C5F<h2 style=";text-align:left;direction:ltr"> 11 <h2 style=";text-align:left;direction:ltr"> C6F<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)2N = C(CH3)O(CH3)2SiCH2CH2C6F<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> C7F<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> CH2CH2Si(CH3)2N = C(CH3)O(CH3)2SiCH2CH2C7F<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> C8F<h2 style=";text-align:left;direction:ltr"> 17CH2CH2Si(CH3)2N=C(CH3)O(CH3)2SiCH2CH2C8F 17 , CF3CH2CH2Si(CH3)(H)N=C(CH3)O(CH3)(H)SiCH2CH2CF3 and other bis(alkylsilyl)acetamides; compounds obtained by replacing the methyl group of -N=C(CH3)O- in the above compounds with a hydrogen atom, ethyl, propyl, butyl, trifluoromethyl, pentafluoroethyl, heptafluoropropyl, nonafluorobutyl or the like. In addition, R of the above general formula [5] 8 and R 10 The options are different.

[0071] When f and g in the general formula [5] are 0, water repellency can be easily maintained in the cleaning after the protective film is formed, which is preferred.

[0072] Furthermore, if R in the above general formula [5] 8 and R 10 A combination of two -CH 3 groups and one linear alkyl group is more preferred because the protective film can be formed homogeneously.

[0073] Specific examples of the silylating agent represented by the general formula [6] include monomethylsilylimidazole, monoethylsilylimidazole, monopropylsilylimidazole, monobutylsilylimidazole, dimethylsilylimidazole, trimethylsilylimidazole, ethyldimethylsilylimidazole, propyldimethylsilylimidazole, butyldimethylsilylimidazole, monomethylsilyltriazole, monoethylsilyltriazole, monopropylsilyltriazole, monobutylsilyltriazole, dimethylsilyltriazole, trimethylsilyltriazole, ethyldimethylsilyltriazole, propyldimethylsilyltriazole, and butyldimethylsilyltriazole; and substances in which the above imidazole structure is substituted with a benzimidazole structure, substances in which the above triazole structure is substituted with a benzotriazole structure, and the like.

[0074] When j in the general formula [6] is 0, water repellency can be easily maintained in the cleaning after the protective film is formed, which is preferred.

[0075] Furthermore, if the above R 11 A combination of two -CH 3 groups and one linear alkyl group is more preferred because the protective film can be formed homogeneously.

[0076] In addition, the chemical solution for forming a water-repellent protective film of the present invention may contain a plurality of the above-mentioned silylating agents, and may further contain a silylating agent other than the compounds represented by the above-mentioned general formulae [3] to [6]. For example, by containing at least one selected from the group consisting of the compounds represented by the above-mentioned general formulae [3] to [6] and at least one selected from the group consisting of the compounds represented by the above-mentioned general formula [7], there is a tendency to obtain a more excellent water-repellent imparting effect, which is preferred.

[0077] Specific examples of the silylating agent represented by the general formula [7] include [(CH3)3Si]2NH, [(CH3)2Si(H)]2NH, [C2H5Si(CH3)2]2NH, [(C2H5)2Si(CH3)]2NH, [(C2H5)3Si]2NH, [C3H7Si(CH3)2]2NH, [(C3H7)2Si(CH3)]2NH, [(C3H7)3Si]2NH, [C4H9(CH3)2Si]2NH, [C5H 11 (CH3)2Si〕2NH、〔C6H 13 (CH3)2Si〕2NH、〔C7H 15 (CH3)2Si〕2NH、〔C8H 17 (CH3)2Si〕2NH、〔C9H 19 (CH3)2Si〕2NH、〔C 10 H 21 (CH3)2Si〕2NH、〔C 11 H 23 (CH3)2Si〕2NH、〔C 12 H 25 (CH3)2Si〕2NH、〔C 13 H 27 (CH3)2Si〕2NH、〔C 14 H 29 (CH3)2Si〕2NH、〔C 15 H 31 (CH3)2Si〕2NH、〔C 16 H 33 (CH3)2Si〕2NH、〔C 17 H 35 (CH3)2Si〕2NH、〔C 18 H 37 (CH3)2Si]2NH, [CF3C2H4(CH3)2Si]2NH, [C2F5C2H4(CH3)2Si]2NH, [C3F7C2H4(CH3)2Si]2NH, [C4F9C2H4(CH3)2Si]2NH, [C5F 11C2H4(CH3)2Si〕2NH、〔C6F 13 C2H4(CH3)2Si〕2NH、〔C7F 15 C2H4(CH3)2Si〕2NH、〔C8F 17 C2H4(CH3)2Si〕2NH, [C3H7(C2H5)2Si]2NH, [C4H9(C2H5)2Si]2NH, [C5H 11 (C2H5)2Si〕2NH、〔C6H 13 (C2H5)2Si〕2NH、〔C7H 15 (C2H5)2Si〕2NH、〔C8H 17 (C2H5)2Si〕2NH、〔C9H 19 (C2H5)2Si〕2NH、〔C 10 H 21 (C2H5)2Si〕2NH、〔C 11 H 23 (C2H5)2Si〕2NH、〔C 12 H 25 (C2H5)2Si〕2NH、〔C 13 H 27 (C2H5)2Si〕2NH、〔C 14 H 29 (C2H5)2Si〕2NH、〔C 15 H 31 (C2H5)2Si〕2NH、〔C 16 H 33 (C2H5)2Si〕2NH、〔C 17 H 35 (C2H5)2Si〕2NH、〔C 18 H 37 (C2H5)2Si〕2NH, etc.

[0078] If the above l in the general formula [7] is 0, it is preferable because water repellency can be easily maintained during cleaning after the protective film is formed as described later. 12 A combination of two -CH 3 groups and one linear alkyl group is more preferred because the protective film can be formed homogeneously.

[0079] About (II) Nitrogen-containing compounds

[0080] When at least one nitrogen-containing compound among the compounds represented by the following general formulas [1] and [2] is used, the reactivity of the silylating agent with the surface of the wafer containing silicon element is greatly improved, and a protective film can be formed in a short time.

[0081]

[0082] [In formulas [1] and [2], R 1 Each of them is independently selected from a hydrogen atom, a -C≡N group, a -NO2 group, and a hydrocarbon group in which a part or all of the hydrogen elements are optionally replaced by fluorine elements, wherein the hydrocarbon group optionally contains oxygen atoms and / or nitrogen atoms, and when containing nitrogen atoms, it presents a non-cyclic structure. 2 Selected from hydrogen atoms, -C≡N groups, -NO2 groups, alkylsilyl groups, and hydrocarbon groups in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, wherein the hydrocarbon groups optionally have oxygen atoms and / or nitrogen atoms, and when nitrogen atoms are included, the hydrocarbon groups present a non-cyclic structure.]

[0083] Examples of the hydrocarbon group include linear or branched groups such as methyl, ethyl, propyl, and butyl; and cyclic groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0084] The hydrocarbon group may have an oxygen atom. Examples of such groups include linear, branched or cyclic alkoxy groups such as methoxy, ethoxy, propoxy and butoxy. The hydrocarbon group may have an ether bond with an oxygen atom between carbon atoms of the hydrocarbon group.

[0085] The hydrocarbon group may have a nitrogen atom. In this case, for example, there may be mentioned groups having a primary amino group to a tertiary amino group in the hydrocarbon group.

[0086] In addition, the above (II) can be modified by changing R 1 , R 2 Thus, nitrogen-containing compounds with various basicities can be prepared. For example, in the above general formulas [1] and [2], R 1 , R 2 When an electron donating group is selected, the electron density around the nitrogen atom double-bonded with the carbon atom increases, and the overall basicity can be increased. The basicity of (II) above can be selected according to the water repellency effect sought in the applied pattern and its compatibility with the type of film on the surface.

[0087] However, from the viewpoint of imparting water repellency, the above R 1 and R 2 Preferably, it is an electron donating group. 1It is preferably a group selected from a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. Here, as the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, etc. are listed. In addition, as the alkoxy group having 1 to 6 carbon atoms, specifically, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, n-hexyl, etc. are listed. In addition, the above R 2 It is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkylsilyl group represented by the following general formula [8].

[0088] -〔Si(R 13 ) m (H) n 〕 [8]

[0089] [R 13 They are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms, m and n are integers of 0 to 3, and the total of m and n is 3.]

[0090] In addition, examples of relatively easily available compounds among the compounds represented by the general formula [1] include guanidine (solid at 25°C and 1.0 atmosphere), 1,1,3,3-tetramethylguanidine (liquid at 25°C and 1.0 atmosphere), 2-tert-butyl-1,1,3,3-tetramethylguanidine (liquid at 25°C and 1.0 atmosphere), 1,3-diphenylguanidine (solid at 25°C and 1.0 atmosphere), and 1,2,3-triphenylguanidine (solid at 25°C and 1.0 atmosphere).

[0091] Examples of the compound represented by the general formula [2] include 2-carbamoylacetamidine (liquid at 25°C and 1.0 atm), 2-amino-2-carbamoylacetamidine (liquid at 25°C and 1.0 atm), 2-aminoacetamidine (liquid at 25°C and 1.0 atm), acetamidine (liquid at 25°C and 1.0 atm), N,N'-diphenylformamidine (solid at 25°C and 1.0 atm), and 2,2,3,3,3-pentafluoropropamidine (solid at 25°C and 1.0 atm). Examples of the relatively easily available compounds include N,N'-diphenylformamidine and 2,2,3,3,3-pentafluoropropamidine.

[0092] From the viewpoint of obtaining a good effect of imparting water repellency, the above-mentioned (II) is preferably at least one nitrogen-containing compound among the compounds represented by the above-mentioned general formula [1].

[0093] The above (II) is a catalytic component that promotes the reaction between the above silylating agent and the surface of the wafer containing silicon element. It should be noted that this component can be a component that forms a part of the water-repellent protective film. When the nitrogen-containing heterocyclic compound that does not contain silicon element and is described in Patent Document 1 as such a catalytic component is dissolved in a solvent together with a silylating agent, most of them need to be dissolved for a long time, and sometimes the effect of imparting water repellency is not sufficient. From the perspective of the dissolution time of the above-mentioned raw materials and the effect of imparting water repellency, as (II), it is preferred to use a compound that is liquid at 25°C and 1.0 atmosphere, and it is particularly preferred to use a compound that is liquid at 25°C and 1.0 atmosphere among the compounds represented by the above general formula [1]. Specifically, 1,1,3,3-tetramethylguanidine, 2-tert-butyl-1,1,3,3-tetramethylguanidine, 2-trimethylsilyl-1,1,3,3-tetramethylguanidine, etc. can be listed.

[0094] About (III) Organic Solvents

[0095] The type of the organic solvent is not particularly limited as long as it is an organic solvent that can dissolve the above-mentioned components (I) and (II).

[0096] It should be noted that if the concentration of (I) relative to the total amount of 100% by mass of the above (I) to (III) is 1 to 50% by mass, it is easy to form a protective film uniformly on the surface of the wafer containing the silicon element, so it is preferred. When it is less than 1% by mass, there is a tendency that the effect of imparting water repellency becomes insufficient. In addition, if it exceeds 50% by mass, it is not preferred from the viewpoint of cost. It is further preferably 1 to 30% by mass, and more preferably 1 to 20% by mass.

[0097] In addition, if the concentration of (II) relative to the total amount of 100% by mass of (I) to (III) is 0.01 to 30% by mass, it is easy to form a protective film uniformly on the surface of the wafer containing the silicon element, so it is preferred. When it is less than 0.01% by mass, there is a tendency that the effect of imparting water repellency is small. In addition, if it exceeds 30% by mass, there is a possibility that it will remain in the wafer in the form of impurities, and the viscosity of the chemical solution for forming the water-repellent protective film increases, which is not preferred from the perspective of ease of liquid adjustment. It is further preferred to be 0.05 to 20% by mass, and more preferably 0.1 to 10% by mass.

[0098] As the above-mentioned (III) organic solvent, suitable examples include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide-based solvents, lactone-based solvents, carbonate-based solvents, substances without OH groups among derivatives of polyols, solvents containing nitrogen elements without NH groups, silicone solvents and other aprotic solvents, or mixtures thereof. Among them, if hydrocarbons, esters, ethers, halogen-containing solvents, substances without OH groups among derivatives of polyols, or mixtures thereof are used, a water-repellent protective film can be formed on the surface of a silicon-containing wafer in a short time, and thus it is more preferred.

[0099] Examples of the hydrocarbons include hexane, heptane, octane, nonane, decane, dodecane, tetradecane, hexadecane, octadecane, eicosane, cyclohexane, methylcyclohexane, decahydronaphthalene, benzene, toluene, xylene, diethylbenzene, etc.; examples of the esters include ethyl acetate, propyl acetate, butyl acetate, ethyl acetoacetate, etc.; examples of the ethers include diethyl ether, dipropyl ether, ethyl butyl ether, dibutyl ether, ethyl amyl ether, diamyl ether, methylcyclopentyl ether, ethyl hexyl ether, dihexyl ether, dioctyl ether, diphenyl ether. , tetrahydrofuran, dioxane, methyl perfluoropropyl ether, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, methyl perfluorohexyl ether, ethyl perfluorohexyl ether, etc.; examples of the above-mentioned ketones include acetone, acetylacetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, cyclohexanone, isophorone, etc.; examples of the above-mentioned halogen-containing solvents include perfluorooctane, perfluorononane, perfluorocyclopentane, perfluorocyclohexane, hexafluorobenzene and other perfluorocarbons; 1,1,1,3,3-pentafluorobutane, octafluorocyclopentane, 2,3-dihydrodecafluoropentane, ZEORORA H (manufactured by ZEON Co., Ltd. of Japan) and other hydrofluorocarbons; methyl perfluoroisobutyl ether, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, ethyl perfluoroisobutyl ether, ASAHIKLIN AE-3000 (manufactured by Asahi Glass Co., Ltd.); hydrofluoroethers such as Novec7100, Novec7200, Novec7300, Novec7600 (all manufactured by 3M Co.); chlorocarbons such as tetrachloromethane; hydrochlorocarbons such as chloroform; chlorofluorocarbons such as dichlorodifluoromethane; chlorofluorocarbons such as 1,1-dichloro-2,2,3,3,3-pentafluoropropane, 1,3-dichloro-1,1,2,2,3-pentafluoropropane, 1-chloro-3,3,3-trifluoropropene, 1,2-dichloro-3,3,3-trifluoropropene;Examples of the above-mentioned sulfoxide-based solvents include dimethyl sulfoxide, and examples of the above-mentioned lactone-based solvents include γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-heptanolactone, γ-octalactone, γ-nonalactone, γ-decanolactone, γ-undecalactone, γ-dodecalactone, δ-valerolactone, δ-caprolactone, δ-octalactone, δ-nonalactone, δ-decanolactone, δ-undecalactone, δ-dodecalactone, ε-caprolactone, and examples of the above-mentioned carbonate-based solvents include dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, and propylene carbonate, and examples of the above-mentioned polyol derivatives that do not have an OH group include ethyl carbonate. Glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, diethylene glycol dibutyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol diacetate, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, triethylene glycol butyl methyl ether, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, triethylene glycol triethylene glycol monobutyl ether acetate, triethylene glycol diacetate, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, tetraethylene glycol monomethyl ether acetate, tetraethylene glycol monoethyl ether acetate, tetraethylene glycol monobutyl ether acetate, tetraethylene glycol diacetate, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol diacetate, dipropylene glycol dimethyl ether, dipropylene glycol methyl propyl ether, dipropylene glycol diethyl ether, dipropylene glycol dibutyl ether, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol Monobutyl ether acetate, dipropylene glycol diacetate, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol dibutyl ether, tripropylene glycol monomethyl ether acetate, tripropylene glycol monoethyl ether acetate, tripropylene glycol monobutyl ether acetate, tripropylene glycol diacetate, tetrapropylene glycol dimethyl ether, tetrapropylene glycol monomethyl ether acetate, tetrapropylene glycol diacetate, butanediol dimethyl ether, butanediol monomethyl ether acetate, butanediol diacetate, glycerol triacetate, etc. Examples of the above-mentioned nitrogen-containing solvents having no NH group include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, triethylamine, pyridine, etc.;

[0100] Among the above-mentioned organic solvents, from the viewpoint of solubility of (I) and (II), it is preferred to use at least one organic solvent selected from the group consisting of the above-mentioned hydrocarbons, esters, sulfoxide-based solvents, and substances having no OH group among derivatives of polyols, and the amount of the suitable solvent is preferably 50 to 100% by mass relative to 100% by mass of the total amount of the above-mentioned (III).

[0101] In addition, the chemical solution for forming a water-repellent protective film of the present invention may be stored in a state where the raw materials are divided into two or more parts and mixed before use. For example, the solution of (I) and the solution of (III) and the solution of (II) and the solution of (III) may be mixed before use; the solution of (I) and the solution of (II) and the solution of (III) may be mixed before use; the solution of (I) and the solution of (III) and the solution of (II) may be mixed before use.

[0102] Cleanliness of chemical solutions (chemical solution raw materials)

[0103] In addition, the total amount of water contained in the above-mentioned (I) to (III) before preparing the above-mentioned chemical solution is preferably less than 5000 mass ppm relative to the total amount of (I) to (III). When the total amount of water exceeds 5000 mass ppm, there is a tendency to reduce the effect of imparting water repellency. Therefore, the less the total amount of the above-mentioned water, the more preferred it is, and it is particularly preferably less than 500 mass ppm, and more preferably less than 200 mass ppm. Furthermore, if the amount of water present is large, the storage stability of the above-mentioned chemical solution is easily reduced. Therefore, the water content is preferably less, preferably less than 100 mass ppm, and more preferably less than 50 mass ppm. It should be noted that the less the water content, the more preferred it is, as long as it is within the above-mentioned content range, it can be more than 0.1 mass ppm. Therefore, the above-mentioned (I) to (III) before preparing the above-mentioned chemical solution preferably do not contain a large amount of water.

[0104] In addition, the number of particles larger than 0.2 μm obtained by measuring particles using a light scattering liquid particle detector in the liquid phase of the chemical solution is preferably 100 or less per 1 mL of the chemical solution. If the number of particles larger than 0.2 μm exceeds 100 per 1 mL of the chemical solution, it is possible that the particles may induce pattern damage to the wafer containing silicon elements, which may cause a decrease in the yield and reliability of the device, so it is not preferred. In addition, if the number of particles larger than 0.2 μm is less than 100 per 1 mL of the chemical solution, cleaning with solvents or water can be omitted or reduced after the protective film is formed, so it is preferred. It should be noted that the fewer the number of particles larger than 0.2 μm, the better, but as long as it is within the above-mentioned content range, there can be more than 1 per 1 mL of the chemical solution. It should be noted that the particle measurement in the liquid phase form in the chemical solution of the present invention is carried out using a commercially available measuring device in a light scattering liquid particle measurement method using a laser as a light source, and the particle size refers to the light scattering equivalent diameter based on the PSL (polystyrene latex) standard particle standard.

[0105] Here, the above-mentioned particles refer to particles of dust, dust, organic solids, inorganic solids, etc. contained in the form of impurities in the raw materials; particles of dust, dust, organic solids, inorganic solids, etc. entrained in the form of pollutants in the preparation of chemical solutions, and substances that ultimately do not dissolve in the chemical solution but exist in the form of particles belong to these particles.

[0106] In addition, the content of each element (metal impurities) of Na, Mg, K, Ca, Mn, Fe, Cu, Li, Al, Cr, Ni, Zn and Ag in the above-mentioned chemical solution is preferably 0.1 mass ppb or less relative to the total amount of the chemical solution. If the content of the above-mentioned metal impurities exceeds 0.1 mass ppb relative to the total amount of the chemical solution, it is possible to increase the junction leakage current of the device, which becomes a cause of reduced device yield and reliability, so it is not preferred. In addition, if the content of the above-mentioned metal impurities is 0.1 mass ppb or less relative to the total amount of the chemical solution, it is preferred because the cleaning of the wafer surface (protective film surface) with a solvent or water after the above-mentioned protective film is formed on the wafer surface can be omitted or reduced. Therefore, the less the content of the above-mentioned metal impurities, the better, but as long as it is within the above-mentioned content range, each element can be 0.001 mass ppb or more relative to the total amount of the chemical solution.

[0107] 2. About water-repellent protective film

[0108] In the present invention, the water-repellent protective film refers to a film that reduces the wettability of the wafer surface by being formed on the wafer surface, that is, a film that imparts water repellency. In the present invention, water repellency means reducing the surface energy of the surface of an article, and reducing the interaction (interface) between water, other liquids and the surface of the article, such as hydrogen bonds, intermolecular forces, etc. In particular, the effect of reducing the interaction with water is large, and it also has the effect of reducing the interaction with a mixture of water and a liquid other than water, and a liquid other than water. By reducing this interaction, the contact angle between the liquid and the surface of the article can be increased. It should be noted that the water-repellent protective film can be formed by the above-mentioned silylating agent, and can also contain a reactant with the silylating agent as the main component.

[0109] 3. About Chip

[0110] The above-mentioned wafer includes: a wafer having a film containing silicon, such as silicon oxide or silicon nitride, formed on the wafer surface; or, when the above-mentioned concave-convex pattern is formed, at least a portion of the surface of the concave-convex pattern contains silicon, such as silicon oxide or silicon nitride, containing silicon. In addition, for a wafer composed of multiple components containing at least silicon, a protective film can also be formed on the surface of the component containing silicon. The wafer composed of multiple components also includes: a wafer having components containing silicon, such as silicon oxide and silicon nitride, formed on the wafer surface; or, when the concave-convex pattern is formed, at least a portion of the concave-convex pattern forms a wafer containing silicon, such as silicon oxide and silicon nitride. It should be noted that the surface of the portion containing silicon in the above-mentioned concave-convex pattern that can be formed with the above-mentioned chemical solution is the surface of the portion containing silicon.

[0111] Generally speaking, in order to obtain a wafer with a fine concavo-convex pattern on the surface, first, after applying a resist on the smooth wafer surface, the resist is exposed through a resist mask, and the exposed resist or the unexposed resist is etched away, thereby making a resist layer with a desired concavo-convex pattern. In addition, by pressing a mold with a pattern on the resist layer, a resist layer with a concavo-convex pattern can also be obtained. Then, the wafer is etched. At this time, the wafer surface corresponding to the concave portion of the resist layer pattern is selectively etched. Finally, if the resist layer is peeled off, a wafer with a fine concavo-convex pattern can be obtained.

[0112] After the wafer surface is made into a surface with a fine concavo-convex pattern, the surface is cleaned with an aqueous cleaning liquid, and the aqueous cleaning liquid is removed by drying, etc. If the width of the concave portion is small and the aspect ratio of the convex portion is large, pattern collapse is likely to occur. Figure 1 and Figure 2 Defined as recorded in . Figure 1 A schematic diagram showing a wafer 1 having a surface formed with a fine concavo-convex pattern 2 when viewed from an oblique angle is shown. Figure 2 express Figure 1 A portion of the a-a' section in Figure 2 As shown, the width 5 of the concave portion is represented by the interval between adjacent convex portions 3, and the aspect ratio of the convex portion is represented by the value obtained by dividing the height 6 of the convex portion by the width 7 of the convex portion. Pattern collapse in the cleaning process is likely to occur when the width of the concave portion is 70 nm or less, especially 45 nm or less, and the aspect ratio is 4 or more, especially 6 or more.

[0113] 4. About the surface treatment of wafer

[0114] Before the wafer having a fine concave-convex pattern on its surface obtained by etching as described above is subjected to surface treatment using the chemical solution of the present invention, it can be cleaned using an aqueous cleaning liquid to remove etching residues, etc., or after the cleaning, the aqueous cleaning liquid retained in the concave portion can be replaced with a cleaning liquid different from the aqueous cleaning liquid (hereinafter referred to as "cleaning liquid A") and further cleaned.

[0115] Examples of the aqueous cleaning solution include water or an aqueous solution obtained by mixing water with at least one of an organic solvent, hydrogen peroxide, ozone, an acid, an alkali, and a surfactant (for example, a water content of 10% by mass or more).

[0116] The cleaning solution A refers to an organic solvent, a mixture of the organic solvent and an aqueous cleaning solution, or a cleaning solution in which at least one of an acid, an alkali, and a surfactant is mixed.

[0117] In the present invention, as long as a cleaning device that can maintain the chemical solution and cleaning liquid in the liquid state in at least the concave part of the concave-convex pattern of the wafer is used, the cleaning method of the wafer is not particularly limited. As the cleaning method of the wafer, there can be listed: a single-wafer method represented by a cleaning method using a rotating cleaning device as follows, wherein the rotating cleaning device keeps the wafer almost horizontally rotating while supplying liquid near the rotation center, thereby cleaning the wafers one by one; a batch method using a cleaning device that immerses multiple wafers in a cleaning tank for cleaning. It should be noted that when supplying the protective film forming agent, chemical solution, and cleaning liquid in the liquid state to at least the concave part of the concave-convex pattern of the wafer, the form of the protective film forming agent, chemical solution, and cleaning liquid is not particularly limited as long as it becomes a liquid when maintained in the concave part, and there are, for example, liquids, vapors, etc.

[0118] Examples of organic solvents, which are one of the preferred examples of the cleaning solution A, include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, lactone solvents, carbonate solvents, alcohols, derivatives of polyols, and solvents containing nitrogen elements.

[0119] The protective film forming chemical solution of the present invention is used by replacing the aqueous cleaning solution or cleaning solution A with the chemical solution. The replaced chemical solution may be replaced with a cleaning solution different from the chemical solution (hereinafter referred to as "cleaning solution B").

[0120] As described above, after cleaning with the aqueous cleaning liquid and the cleaning liquid A, the cleaning liquid is replaced with a chemical solution for forming a protective film, and the protective film is formed on at least the surface of the concave portion of the concave-convex pattern while the chemical solution is maintained in at least the concave portion of the concave-convex pattern. The protective film of the present invention is not necessarily formed continuously, and is not necessarily formed uniformly. In order to impart more excellent water repellency, it is more preferably formed continuously and uniformly.

[0121] Figure 3 A schematic diagram showing a state in which the protective film forming chemical solution 8 is retained in the recessed portion 4 . Figure 3 A schematic diagram of the wafer shows Figure 1 At this time, a protective film is formed on the surface of the recessed portion 4 to make the surface water-repellent.

[0122] If the temperature is increased, the chemical solution for forming a protective film can easily form the above-mentioned protective film in a shorter time. The temperature at which a homogeneous protective film is easily formed is preferably maintained at a temperature above 10°C and below the boiling point of the chemical solution, and is particularly preferably maintained at a temperature above 15°C and below a temperature 10°C lower than the boiling point of the chemical solution. Regarding the temperature of the above-mentioned chemical solution, it is preferred to maintain the temperature even when it is maintained in at least the concave part of the concave-convex pattern. It should be noted that the boiling point of the chemical solution refers to the boiling point of the component that is measured most by mass ratio among the components contained in the chemical solution for forming a protective film.

[0123] After forming the protective film as described above, the chemical solution remaining in at least the concave part of the concave-convex pattern can be replaced with a cleaning solution B, and then the process is transferred to the drying step. Examples of the cleaning solution B include an aqueous cleaning solution, an organic solvent, a mixture of an aqueous cleaning solution and an organic solvent, or a liquid obtained by mixing at least one of an acid, an alkali, and a surfactant therein, and a mixture of these and a chemical solution for forming a protective film. From the viewpoint of removing particles and metal impurities, the cleaning solution B is more preferably water, an organic solvent, or a mixture of water and an organic solvent.

[0124] Examples of organic solvents, which are one of the preferred examples of the cleaning solution B, include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide-based solvents, alcohols, polyol derivatives, and nitrogen-containing solvents.

[0125] Furthermore, when an organic solvent is used as the cleaning liquid B, the water repellency of the protective film formed on the wafer surface by the chemical solution of the present invention may be less likely to be reduced by cleaning with the cleaning liquid B.

[0126] The schematic diagram of the case where the recessed portion 4 made water-repellent by the chemical solution for forming a protective film holds the liquid is shown in FIG. Figure 4 . Figure 4 A schematic diagram of the wafer shows Figure 1 A portion of the aa' cross section of the concavo-convex pattern is formed with a protective film 10 by the chemical solution and is made water-repellent. Furthermore, the protective film 10 is also retained on the wafer surface when the liquid 9 is removed from the concavo-convex pattern.

[0127] When a protective film 10 is formed on at least the concave surface of the concave-convex pattern of the wafer using a protective film forming chemical solution, if the contact angle when water is maintained on the surface is 50 to 130°, it is difficult for the pattern to collapse, so it is preferred. If the contact angle is large, the water repellency is excellent, so it is more preferably 60 to 130°, and particularly preferably 65 to 130°. In addition, before and after cleaning with cleaning liquid B, the reduction in the above contact angle (contact angle before cleaning with cleaning liquid B - contact angle after cleaning with cleaning liquid B) is preferably less than 10°.

[0128] Next, the liquid retained in the concave portion 4 where the protective film is formed using the above-mentioned chemical solution is removed from the concave-convex pattern by drying. At this time, the liquid retained in the concave portion may be the above-mentioned chemical solution, the above-mentioned cleaning solution B, or a mixture thereof. The above-mentioned mixed solution contains (I) and (II) contained in the chemical solution in a manner lower than the concentration of the chemical solution for forming the protective film. The mixed solution may be a liquid in this state during the process of replacing the above-mentioned chemical solution with the cleaning solution B, or may be a mixed solution obtained by pre-mixing the above-mentioned (I) and (II) with the cleaning solution B. From the viewpoint of the cleanliness of the chip, water, an organic solvent, or a mixture of water and an organic solvent is preferred. In addition, once the liquid is removed from the surface of the above-mentioned concave-convex pattern, the cleaning solution B is retained on the surface of the above-mentioned concave-convex pattern, and then dried.

[0129] It should be noted that when cleaning with cleaning liquid B after forming the protective film, from the viewpoint of removing particles and impurities on the surface of the above-mentioned concave-convex pattern, the cleaning time, that is, the time for keeping the cleaning liquid B is preferably 10 seconds or more, more preferably 20 seconds or more. From the viewpoint of maintaining the water repellency of the protective film formed on the surface of the above-mentioned concave-convex pattern, if an organic solvent is used as the cleaning liquid B, there is a tendency that the water repellency of the wafer surface is easily maintained even if the cleaning is performed. On the other hand, if the above-mentioned cleaning time becomes too long, the productivity deteriorates, so it is preferably within 15 minutes.

[0130] The liquid retained in the concavo-convex pattern is removed by the above drying, which is preferably performed by a known drying method such as spin drying, IPA (2-propanol) vapor drying, Marangoni drying, heating drying, hot air drying, air blowing drying, vacuum drying, etc.

[0131] After the above drying, the protective film 10 can be further removed. When removing the water-repellent protective film, it is effective to cut the CC bond and the CF bond in the water-repellent protective film. The method is not particularly limited as long as the above bonds can be cut, and examples thereof include irradiating the wafer surface with light, heating the wafer, exposing the wafer to ozone, irradiating the wafer surface with plasma, and performing corona discharge on the wafer surface.

[0132] When the protective film 10 is removed by light irradiation, it is preferred to irradiate ultraviolet rays having a wavelength shorter than 340 nm and 240 nm, which are energies equivalent to the bond energies of CC bonds and CF bonds in the protective film 10, i.e., 83 kcal / mol and 116 kcal / mol, respectively. As the light source, a metal halide lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an excimer lamp, a carbon arc, etc. can be used. If it is a metal halide lamp, the ultraviolet irradiation intensity is preferably 100 mW / cm, for example, as measured by an illuminance meter (irradiation 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]). 2 More than 200 mW / cm 2 It should be noted that the irradiation intensity is less than 100mW / cm 2 When the protective film 10 is removed, a long time is required. In addition, if a low-pressure mercury lamp is used, ultraviolet rays with a shorter wavelength are irradiated, so the protective film 10 can be removed in a short time even if the irradiation intensity is low, so it is preferred.

[0133] In addition, when removing the protective film 10 by light irradiation, it is particularly preferred that ozone is generated while decomposing the constituents of the protective film 10 by ultraviolet rays. If the constituents of the protective film 10 are oxidized and volatilized by the ozone, the processing time is shortened. As the light source, a low-pressure mercury lamp, an excimer lamp, etc. can be used. In addition, the wafer can be heated while irradiating with light.

[0134] When heating the wafer, it is preferred to heat the wafer at 400 to 1000° C., preferably 500 to 900° C. The heating time is preferably 10 seconds to 60 minutes, preferably 30 seconds to 10 minutes. In addition, ozone exposure, plasma irradiation, corona discharge, etc. may be used in combination in this process. In addition, light irradiation may be performed while heating the wafer.

[0135] Methods for removing the protective film 10 by heating include: a method of contacting the wafer with a heat source, a method of placing the wafer in a heated atmosphere such as a heat treatment furnace, etc. It should be noted that the method of placing the wafer in a heated atmosphere is an industrially advantageous method that is easy to operate and completes the treatment in a short time, and has high treatment capacity, even when a plurality of wafers are treated, because it is easy to uniformly impart energy for removing the protective film 10 to the wafer surface.

[0136] When the wafer is exposed to ozone, it is preferred that ozone generated by ultraviolet irradiation using a low-pressure mercury lamp or the like, or by high-voltage low-temperature discharge, etc., be supplied to the wafer surface. The wafer may be exposed to ozone while being irradiated with light or heated.

[0137] By combining the above-mentioned light irradiation, heating, ozone exposure, plasma irradiation, and corona discharge, the protective film on the wafer surface can be effectively removed.

[0138] Example

[0139] Hereinafter, examples will be described to more specifically disclose the embodiments of the present invention. However, it should be noted that the present invention is not limited to these examples.

[0140] The process of making the wafer surface into a surface with a concavo-convex pattern and replacing the cleaning liquid held in at least the concave portion of the concavo-convex pattern with another cleaning liquid is a technology that has been studied and established in various ways in other documents, so the effect of imparting water repellency to the chemical solution for forming a protective film is evaluated in the present invention. It should be noted that in the examples, water, which is a representative of aqueous cleaning liquids, was used as the liquid in contact with the wafer surface when evaluating the contact angle.

[0141] However, in the case of a wafer having a concavo-convex pattern on its surface, it is impossible to accurately evaluate the contact angle of the protective film 10 itself formed on the concavo-convex pattern surface.

[0142] The contact angle of a water droplet is evaluated by dropping a few μl of water droplets on the surface of a sample (substrate) and measuring the angle between the water droplet and the surface of the substrate, as also described in JIS R3257 "Test method for wettability of substrate glass surface". However, in the case of a wafer with a pattern, the contact angle becomes very large. This is because: due to the occurrence of the Wenzel effect and the Cassie effect, the contact angle is affected by the surface shape (roughness) of the substrate, and the apparent contact angle of the water droplet increases.

[0143] Therefore, in this embodiment, the chemical solution is supplied to a wafer with a smooth surface to form a protective film on the wafer surface, and the protective film is regarded as a protective film formed on the surface of a wafer with a concavo-convex pattern formed on the surface, and various evaluations are performed. It should be noted that in this embodiment, as a wafer with a smooth surface, a "wafer with a SiO2 film" having a SiO2 layer on a silicon wafer with a smooth surface is used.

[0144] The following describes the evaluation method, the preparation of the protective film forming chemical solution, the surface treatment of the wafer using the protective film forming chemical solution, and the evaluation results after the protective film is formed on the wafer.

[0145] [Evaluation Method]

[0146] (A) Dissolution time of raw materials during liquid preparation

[0147] In a glove box set at an ambient temperature of 25° C., raw materials of a protective film forming chemical solution were placed in a mixing container under a nitrogen atmosphere at 1.0 atm.

[0148] The raw materials of the protective film forming chemical solution were mixed while maintaining the ambient temperature at 25° C., and the time (dissolution time) required for all the raw materials to dissolve was visually measured. Of course, the shorter the dissolution time, the easier it is for the raw materials to dissolve, which is preferred.

[0149] Therefore, in the table described below, the case where the raw material dissolved within 30 seconds after stirring at 25°C for more than 5 seconds is recorded as ○, and the case where the raw material dissolved within 5 seconds of stirring is recorded as ◎ as "particularly excellent solubility result". On the other hand, the case where the raw material dissolved if stirring was continued but stirring required more than 30 seconds was recorded as Δ; and the case where all the raw materials could not be dissolved even if stirring was continued for more than 1 hour was recorded as ×.

[0150] (B) Evaluation of contact angle of protective film formed on wafer surface

[0151] About 2 μl of pure water was placed on the surface of the wafer having the protective film formed thereon, and the angle (contact angle) between the water droplet and the wafer surface was measured using a contact angle meter (CA-X model, manufactured by Kyowa Interface Science Co., Ltd.).

[0152] [Example 1]

[0153] (1) Preparation of chemical solution for forming protective film

[0154] In a glove box set at an ambient temperature of 25°C, under a nitrogen atmosphere of 1.0 atm, (I) trimethylsilyl trifluoroacetate〔(CH3)3SiOC(=O)CF3〕(hereinafter referred to as "TMS-TFA"), (II) 2-tert-butyl-1,1,3,3-tetramethylguanidine〔(CH3)2N-C(=NC[CH3]3)-N(CH3)2〕(hereinafter referred to as "tBu-TMG") and (III) propylene glycol monomethyl ether acetate (hereinafter referred to as "PGMEA") as an organic solvent were added to a mixing container in such a manner as to achieve the contents shown in Table 1, and the mixture was mixed while maintaining the ambient temperature at 25°C. As a result, the raw materials dissolved within 5 seconds of stirring to obtain a chemical solution for forming a water-repellent protective film.

[0155] (2) Cleaning of silicon wafers

[0156] A silicon wafer with a smooth thermal oxide film (Si wafer with a thermal oxide film layer with a thickness of 1 μm on the surface) was immersed in a 1 mass % hydrofluoric acid aqueous solution at 25°C for 10 minutes, immersed in pure water at 25°C for 1 minute, and immersed in 2-propanol (iPA) at 25°C for 1 minute.

[0157] (3) Surface treatment of the silicon wafer using a chemical solution for forming a protective film

[0158] The cleaned silicon wafer was immersed in the protective film forming chemical solution prepared by the above "(1) Preparation of protective film forming chemical solution" at 25°C for 20 seconds, immersed in iPA at 25°C for 1 minute, and immersed in pure water at 25°C for 1 minute. Finally, the silicon wafer was taken out of the pure water, and air was blown to remove the pure water on the surface.

[0159] The results of evaluation of the obtained wafer showed, as shown in Table 1, that the contact angle after the surface treatment reached 95°, indicating an excellent water repellency imparting effect.

[0160] [Table 1]

[0161]

[0162] [Comparative Example 1]

[0163] As shown in Table 1, a chemical solution was prepared in the same manner as in Example 1 except that component (II) was not added, and the surface treatment of the wafer was performed, and the evaluation was performed. Comparative Example 1 is an experimental example using a chemical solution for forming a protective film without tBu-TMG. If the contact angle after the surface treatment is less than 10°, the water repellency imparting effect is significantly inferior to the contact angle after the surface treatment of Example 1.

[0164] [Examples 2 to 6, Comparative Examples 2 to 6]

[0165] In Examples 2 to 6, chemical solutions were prepared in the same manner as in Example 1, and surface treatment of wafers was performed, and the evaluation was performed, except that the type and concentration of the silylating agent (I) used in Example 1 were changed. In addition, Comparative Examples 2 to 6 are experimental examples in which chemical solutions were prepared in the same manner as in Examples 2 to 6, and surface treatment of wafers was performed, and the evaluation was performed, except that the component (II) was not added. The results are shown in Table 1.

[0166] It should be noted that in the table or the text thereafter, "MSTFA" refers to N-trimethylsilyl-N-methyltrifluoroacetamide〔(CH3)3Si-N(CH3)C(=O)CF3〕, "BSTFA" refers to N,O-bis(trimethylsilyl)trifluoroacetamide〔(CH3)3Si-N=C(CF3)OSi(CH3)3〕, TMSIm refers to 1-trimethylsilylimidazole, TMS-TriAz refers to 1-(trimethylsilyl)-1,2,4-triazole, and TMS-BzTriAz refers to 1-(trimethylsilyl)-1H-benzotriazole.

[0167] In any of the examples, the contact angle after the surface treatment was significantly larger than that of the comparative example having the corresponding chemical solution composition not containing the component (II), indicating an excellent water repellency-imparting effect.

[0168] [Examples 7 to 11, Comparative Examples 7 to 11]

[0169] The above (II) was set to two types: 1,1,3,3-tetramethylguanidine〔(CH3)2N-C(=NH)-N(CH3)2〕(hereinafter referred to as "TMG") and 2-trimethylsilyl-1,1,3,3-tetramethylguanidine〔(CH3)2N-C(=N-Si[CH3]3)-N(CH3)2〕(hereinafter referred to as "TMS-TMG"), and the concentrations of each were changed as shown in Table 2, and the type and concentration of the silylating agent (I) were changed as shown in Table 2. Except for this, the chemical solution was prepared in the same manner as in Example 1, the surface treatment of the wafer was performed, and the evaluation was performed. In addition, Comparative Examples 7 to 11 are experimental examples as follows: except that the component (II) was not added, the chemical solution was prepared in the same manner as in Examples 7 to 11, the surface treatment of the wafer was performed, and the evaluation was performed. The results are shown in Table 2.

[0170] It should be noted that in the table or the text thereafter, "MSA" refers to N-trimethylsilyl-N-methylacetamide〔(CH3)3Si-N(CH3)C(=O)CH3〕, and "BSA" refers to N,O-bis(trimethylsilyl)acetamide〔(CH3)3Si-N=C(CH3)OSi(CH3)3〕.

[0171] Even when component (II) was changed to TMG and TMS-TMG, the contact angle after surface treatment was significantly larger in all examples than in the comparative examples of the corresponding chemical solution compositions not containing component (II), indicating an excellent water repellency imparting effect.

[0172] [Table 2]

[0173]

[0174] [Examples 12 to 18]

[0175] Examples 12 to 17 are experimental examples in which chemical solutions were prepared in the same manner as in Example 1, except that the type and concentration of the above-mentioned component (II) were changed as shown in Table 3, and the surface treatment of the wafer was performed, and the evaluation was performed. In addition, Example 18 is an experimental example in which chemical solutions were prepared in the same manner as in Example 4, except that the type and concentration of the above-mentioned component (II) were changed as shown in Table 3, and the surface treatment of the wafer was performed, and the evaluation was performed. The results are shown in Table 3.

[0176] In the table or in the text thereafter, "DPhG" means 1,3-diphenylguanidine, "TPhG" means 1,2,3-triphenylguanidine, and "DPhFA" means N,N'-diphenylformamidine.

[0177] [Table 3]

[0178]

[0179] In any of the examples, the contact angle after the surface treatment was significantly larger than that of Comparative Examples 1 and 4, which were composed of chemical solutions without component (II), showing an excellent water repellency imparting effect. It can be confirmed that the same tendency is shown even when various changes are made to the types of (I) and (II).

[0180] [Examples 19 to 24]

[0181] Examples 19 to 21 are experimental examples in which two silylating agents were used in combination as shown in Table 4 without changing the total molar concentration of component (I), and chemical solutions were prepared in the same manner as in Example 1, and surface treatment of wafers was performed, and evaluation was performed. Examples 22 and 23 are experimental examples in which two silylating agents were used in combination as shown in Table 4 without changing the total molar concentration of component (I), and chemical solutions were prepared in the same manner as in Example 14, and surface treatment of wafers was performed, and evaluation was performed. Example 24 is an experimental example in which two silylating agents were used in combination as shown in Table 4 without changing the total molar concentration of component (I), and chemical solutions were prepared in the same manner as in Example 12, and surface treatment of wafers was performed, and evaluation was performed. The results are shown in Table 4.

[0182] It should be noted that, in the table or in the text thereafter, "HMDS" means 1,1,1,3,3,3-hexamethyldisilazane.

[0183] [Table 4]

[0184]

[0185] [Comparative Examples 12 to 14]

[0186] Chemical solutions were prepared in the same manner as in Examples 19 to 21 except that the component (II) was not added, and the surface treatment of the wafer was performed and further evaluated.

[0187] In any of the examples, the contact angle after the surface treatment was larger than that of the comparative example of the corresponding chemical solution composition without the component (II), showing an excellent water repellency imparting effect. It can be confirmed that even if two or more silylating agents are used as the component (I), the same tendency is shown.

[0188] In any of the Examples, a superior water repellency-imparting effect was obtained compared to that of Examples 1, 12, and 14 obtained by using a chemical solution of a corresponding composition containing TMS-TFA alone as the component (I).

[0189] [Examples 25 to 29]

[0190] Examples 25 to 27 are experimental examples in which chemical solutions were prepared in the same manner as in Examples 1, 3, and 4, except that the organic solvent (III) was changed to butyl acetate, and the surface treatment of the wafer was performed, and the evaluation was performed. In addition, Examples 28 and 29 are experimental examples in which chemical solutions were prepared in the same manner as in Examples 2 and 3, except that the organic solvent (III) was changed to n-decane, and the surface treatment of the wafer was performed, and the evaluation was performed. The results are shown in Table 5.

[0191] [Comparative Examples 15 to 19]

[0192] Chemical solutions were prepared in the same manner as in Examples 25 to 29 except that the component (II) was not added, and the surface treatment of the wafer was performed and further evaluated.

[0193] [Table 5]

[0194]

[0195] [Examples 30 to 34]

[0196] Examples 30 to 32 are experimental examples: except that the organic solvent (III) was changed to butyl acetate, chemical solutions were prepared in the same manner as in Examples 12, 9, and 18, and the surface treatment of the wafer was performed, and the evaluation was performed. In addition, Examples 33 and 34 are experimental examples as follows: except that the organic solvent (III) was changed to n-decane, chemical solutions were prepared in the same manner as in Examples 7 and 9, and the surface treatment of the wafer was performed, and the evaluation was performed. The results are shown in Table 5.

[0197] In any of the examples, the contact angle after the surface treatment was significantly larger than that of the comparative example of the corresponding chemical solution composition without component (II), showing an excellent water repellency imparting effect. This confirmed that the same tendency was shown even when the type of organic solvent (III) was changed.

[0198] It can be confirmed that among the embodiments, the embodiments in which component (II) is liquid at 25°C and 1.0 atmosphere (e.g., Examples 1, 12, and 13) have a shorter raw material dissolution time when preparing the chemical solution, and are more preferred, compared with the embodiments in which component (II) is solid at 25°C and 1.0 atmosphere (e.g., Examples 15, 16, and 17).

[0199] [Reference Examples 1 to 44]

[0200] Reference Examples 1 to 21 are experimental examples in which a surface treatment agent is prepared in the same manner as in Example 1, and a surface treatment of a wafer is performed, and then the surface treatment is evaluated, except that component (II) (tBu-TMG) is not used in Example 1, and instead the "nitrogen-containing heterocyclic compound not containing silicon atoms (hereinafter sometimes abbreviated as "nitrogen-containing heterocyclic compound")" shown in Table 6 is used in a manner to achieve the concentration described in Table 6. In addition, Reference Examples 22 to 42 are experimental examples in which the type of organic solvent is further changed, and Reference Examples 43 to 44 are experimental examples in which the type and concentration of the silylating agent and the type of organic solvent are further changed. It should be noted that the nitrogen-containing heterocyclic compound described in Table 6 is equivalent to the "nitrogen-containing heterocyclic compound not containing silicon atoms" described in Tables 1 to 3 of Patent Document 1. The results are shown in Table 6.

[0201] It should be noted that in the table:

[0202] "Im" refers to imidazole,

[0203] "Tet" refers to 1H-tetrazole,

[0204] "5-MeTet" means 5-methyltetrazolyl,

[0205] "Tri" refers to 1,2,4-triazole,

[0206] "BzoTri" refers to 1,2,3-benzotriazole,

[0207] "Pyr" means pyrazole,

[0208] "2-MeIm" means 2-methylimidazole,

[0209] "4-MeIm" means 4-methylimidazole,

[0210] "TFAcIm" means 1-(trifluoroacetyl)imidazole,

[0211] "3-Mer-1,2,4-Tri" refers to 3-mercapto-1,2,4-triazole,

[0212] "5-MeBzoTri" means 5-methyl-1H-benzotriazole,

[0213] "5-AminoTet" means 5-amino-1H-tetrazole,

[0214] "Tet-1-AcOH" refers to 1H-tetrazolyl-1-acetic acid,

[0215] "Tet-5-AcOH" refers to 1H-tetrazolyl-5-acetic acid,

[0216] "5-Mer-1-MeTet" refers to 5-mercapto-1-methyltetrazolyl,

[0217] "5-BnTet" refers to 5-benzyl-1H-tetrazolyl,

[0218] "5-PhTet" means 5-phenyltetrazolyl,

[0219] "5-pTolTet" means 5-(p-tolyl)-1H-tetrazole,

[0220] "5-Mer-1-PhTet" refers to 5-mercapto-1-phenyl-1H-tetrazole,

[0221] "5-MeThiTet" refers to 5-(methylthio)-1H-tetrazole,

[0222] "iOx" refers to isoxazole.

[0223] [Table 6]

[0224]

[0225] In contrast to Reference Examples 1 to 44 in which a nitrogen-containing heterocyclic compound was used instead of component (II), the water repellency imparting effect was poor. In contrast, the protective film forming chemical solution of the present invention exhibited an excellent water repellency imparting effect, and particularly, when the compound represented by the general formula [1] was used, an even better water repellency imparting effect was exhibited.

[0226] In addition, the nitrogen-containing heterocyclic compounds used in the reference examples are mostly solid at 25°C and 1.0 atmosphere and have poor solubility. In contrast, the chemical solution for forming a protective film of the present invention shows excellent solubility, especially when it is liquid at 25°C and 1.0 atmosphere, it shows even better solubility.

[0227] The protective film-forming liquid chemical of the present invention can exert an excellent water repellency-imparting effect and excellent solubility of a raw material in a well-balanced manner.

[0228] Description of Reference Numerals

[0229] 1: Chip

[0230] 2: Fine concave and convex patterns on the wafer surface

[0231] 3: The convex part of the pattern

[0232] 4: Concave part of the pattern

[0233] 5: Width of the concave part

[0234] 6: Height of convex part

[0235] 7: Width of the convex part

[0236] 8: Chemical solution for forming protective film held in recessed portion 4

[0237] 9: Liquid held in recess 4

[0238] 10: Protective film

Claims

1. A chemical solution for forming a water-repellent protective film, which is a chemical solution for forming a water-repellent protective film on a surface of a wafer, wherein the surface of the wafer contains silicon element, The chemical solution for forming a water-repellent protective film comprises: (I) a silylating agent, (II) at least one nitrogen-containing compound among the compounds represented by the following general formulas [1] and [2], and (III) an organic solvent, in, The silylating agent is at least one selected from the group consisting of compounds represented by the following general formulas [3] to [6], (R 3 ) a (H) b Si〔OC(=O)R 4 〕 4-a-b [3] In formula [3], R 3 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally replaced by fluorine elements, R 4 are independently selected from an alkyl group having 1 to 6 carbon atoms in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, a is an integer of 1 to 3, b is an integer of 0 to 2, a The sum of b and b is less than 3; (R 5 ) c (H) d Si〔N(R 6 )C(=O)R 7 〕 4-c-d [4] In formula [4], R 5 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally replaced by fluorine elements, R 6 are each independently a group selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 6 carbon atoms in which a part or all of the hydrogen atoms are optionally substituted with fluorine atoms, and R 7 Each independently selected from an alkyl group having 1 to 6 carbon atoms in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, c is an integer of 1 to 3, d is an integer of 0 to 2, and the sum of c and d is 3 or less; (R 8 ) e (H) f SiN=C(R 9 )OSi(H) g (R 10 ) h [5] In formula [5], R 8 and R 10 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally replaced by fluorine elements, R 9 is a group selected from the group consisting of hydrogen atoms and alkyl groups having 1 to 6 carbon atoms in which a part or all of the hydrogen atoms are optionally substituted by fluorine atoms, e and h are integers of 1 to 3, f and g are integers of 0 to 2, and the total of e and f and the total of g and h are both 3; (R 11 ) i (H) j Si-Y [6] In formula [6], R 11 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, i is an integer of 1 to 3, j is an integer of 0 to 2, the sum of i and j is 3, Y represents a monovalent nitrogen-containing heterocyclic group, Wherein, R of the general formulas [1] and [2] 1 are each independently a group selected from a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms, and R 2 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkylsilyl group represented by the following general formula [8], -〔Si(R 13 ) m (H) n 〕 [8] R 13 Each of them is independently selected from a monovalent hydrocarbon group having 1 to 18 carbon atoms; m and n are integers of 0 to 3, and the total of m and n is 3.

2. The chemical solution for forming a water-repellent protective film according to claim 1, wherein The (II) is liquid at 25°C and 1.0 atm.

3. The chemical solution for forming a water-repellent protective film according to claim 1, wherein The silylating agent further contains at least one selected from the group consisting of compounds represented by the following general formula [7]: In formula [7], R 12 They are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, k is an integer of 1 to 3, l is an integer of 0 to 2, and the total of k and l is 3.

4. The chemical solution for forming a water-repellent protective film according to claim 1, wherein (II) The concentration of the above-mentioned (I) to (III) is 0.01 to 30% by mass based on 100% by mass of the total amount.

5. The chemical solution for forming a water-repellent protective film according to claim 1, wherein The above-mentioned (II) is at least one nitrogen-containing compound among the compounds represented by the above-mentioned general formula [1].

6. The chemical solution for forming a water-repellent protective film according to claim 1, wherein a in the general formula [3], c in the general formula [4], e and h in the general formula [5], and i in the general formula [6] are all 3.

7. The chemical solution for forming a water-repellent protective film according to claim 3, wherein In the general formula [7], k is 3.

8. The chemical solution for forming a water-repellent protective film according to claim 1, wherein R of the general formula [3] 3 At least two of them are methyl groups, and R 5 At least two of them are methyl groups, and R 8 At least two of them are methyl groups, R 10 At least two of them are methyl groups, and R 11 At least two of them are methyl groups.

9. The chemical solution for forming a water-repellent protective film according to claim 3, wherein R of the general formula [7] 12 At least two of them are methyl groups.

10. The chemical solution for forming a water-repellent protective film according to claim 1, wherein (I) The concentration of the above-mentioned (I) to (III) is 1 to 50% by mass based on 100% by mass of the total amount.

11. The chemical solution for forming a water-repellent protective film according to claim 1, wherein The (III) organic solvent is an aprotic solvent.

12. A method for preparing a chemical solution for forming a water-repellent protective film, the chemical solution being used to form a water-repellent protective film on a surface of a wafer, the surface of the wafer containing silicon. In the method, At least (I) a silylating agent, (II) at least one nitrogen-containing compound among the compounds represented by the following general formulas [1] and [2], and (III) an organic solvent are mixed under the conditions of 15 to 35° C. and 0.5 to 1.5 atm to prepare a water-repellent protective film-forming chemical solution containing (I) to (III) in a solution state, in, The silylating agent is at least one selected from the group consisting of compounds represented by the following general formulas [3] to [6], (R 3 ) a (H) b Si〔OC(=O)R 4 〕 4-a-b [3] In formula [3], R 3 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally replaced by fluorine elements, R 4 are independently selected from an alkyl group having 1 to 6 carbon atoms in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, a is an integer of 1 to 3, b is an integer of 0 to 2, a The sum of b and b is less than 3; (R 5 ) c (H) d Si[N(R 6 )C(=O)R 7 〕 4-c-d [4] In formula [4], R 5 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally replaced by fluorine elements, R 6 are each independently a group selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 6 carbon atoms in which a part or all of the hydrogen atoms are optionally substituted with fluorine atoms, and R 7 Each independently selected from an alkyl group having 1 to 6 carbon atoms in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, c is an integer of 1 to 3, d is an integer of 0 to 2, and the sum of c and d is 3 or less; (R 8 ) e (H) f SiN=C(R 9 )OSi(H) g (R 10 ) h [5] In formula [5], R 8 and R 10 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally replaced by fluorine elements, R 9 is a group selected from the group consisting of hydrogen atoms and alkyl groups having 1 to 6 carbon atoms in which a part or all of the hydrogen atoms are optionally substituted by fluorine atoms, e and h are integers of 1 to 3, f and g are integers of 0 to 2, and the total of e and f and the total of g and h are both 3; (R 11 ) i (H) j Si-Y [6] In formula [6], R 11 are independently selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which a part or all of the hydrogen elements are optionally substituted by fluorine elements, i is an integer of 1 to 3, j is an integer of 0 to 2, the sum of i and j is 3, Y represents a monovalent nitrogen-containing heterocyclic group, Wherein, R of the general formulas [1] and [2] 1 are each independently a group selected from a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms, and R 2 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkylsilyl group represented by the following general formula [8], -〔Si(R 13 ) m (H) n 〕 [8] R 13 Each of them is independently selected from a monovalent hydrocarbon group having 1 to 18 carbon atoms; m and n are integers of 0 to 3, and the total of m and n is 3.

13. A method for producing a surface-treated body, wherein: The surface of a wafer is treated by bringing the chemical solution for forming a water-repellent protective film according to any one of claims 1 to 11 into contact with the surface of the wafer.

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