Substrate processing method, and substrate manufacturing method

Abstract

This substrate processing method comprises: a preparation step for preparing a substrate in which at least a first surface containing silicon oxide and a second surface containing silicon or a silicon compound other than silicone oxide are exposed; a surface modification step for forming an etching selectivity imparting film on at least part of the first surface and at least part of the second surface by means of a silylation process in which a silylation agent is contacted with the first surface and the second surface; and an etching step for selectively etching the second surface relative to the first surface using an etching agent after the surface modification step.

Description

Method for treating substrate and method for manufacturing substrate

[0001] The present invention relates to a method for treating a substrate and a method for manufacturing a substrate.

[0002] Conventionally, fine patterning has been achieved by multiple lithography and etching processes to obtain semiconductor devices. However, in recent years, semiconductor devices have tended to become more highly integrated and miniaturized, and in order to meet these demands, lithography processes have become more complex and costly, creating a need for alternative technologies to lithography.

[0003] As an alternative to lithography, a technology using a self-assembled monolayer (SAM) is being considered. Specifically, this technology involves selectively depositing a self-assembled monolayer (hereinafter simply referred to as a "monolayer") as a masking material or protective material on regions of a substrate that are not to be processed, and then forming or depositing a desired film material on the remaining regions of the substrate (i.e., regions that are to be processed), or performing an etching process.

[0004] Various methods have been investigated for selectively depositing the monolayer, including a method for selectively forming a monolayer based solely on the chemical properties of the substrate surface. Since this method does not limit the combination of non-processing targets and processing targets as long as a monolayer can be selectively formed, various methods for forming a monolayer corresponding to the combination have been investigated. Examples of such techniques include those described in Patent Documents 1 to 3.

[0005] For example, Patent Document 1 discloses a method of supplying a protective film forming gas containing an amine gas to a substrate having a first film and a second film on its surface, each of which is etchable by an etching gas, thereby causing the amine to adsorb to the first film and selectively protect it, and then selectively etching the second film. The claims of this document disclose combinations of the first film and the second film, such as a silicon oxide film and a silicon film, and a SiOCN film and a silicon oxide film, and exemplified protective film forming gases such as hexylamine, dipropylamine, n-octylamine, butylamine, tert-butylamine, decylamine, dodecylamine, dicyclohexylamine, and tetradecylamine.

[0006] Patent Document 2 discloses a method for forming a SAM as a block material on vertical spacers, selectively depositing a high-k film on nanowires between the vertical spacers, and a metal-containing gate electrode layer on the high-k film. This document describes that the vertical spacers include a SiCOH material, a dielectric material having a relative permittivity of less than about 7, or an air gap spacer, and that the nanowires are composed of Si, SiGe, or both Si and SiGe. Furthermore, examples of the end groups of the molecules that form the SAM include thiol, silane, and phosphonate.

[0007] Patent Document 3 describes SiO ２ Using a substrate having a film and a SiN film, ２ A method is disclosed in which a film surface is silylated to form a water-repellent film, one SiN film is subjected to a silylation treatment that does not form a water-repellent film, and then the exposed SiN film is selectively etched (paragraph 0006 of Patent Document 3). Specifically, paragraph 0052 of Patent Document 3 describes that a SiN film (nitride film) does not react with a silylating agent because it does not have a hydroxyl group.

[0008] JP 2021-163775 A JP 2021-528859 A JP 2012-164949 A

[0009] An object of the present invention is to provide a method for treating a substrate which has good etching selectivity for a silicon nitride-containing second surface relative to a silicon oxide-containing first surface and which has excellent liquid drainage properties.

[0010] According to one aspect of the present invention, there is provided the following method for treating a substrate and method for manufacturing a substrate. 1. A method for treating a substrate, comprising: a preparation step of preparing a substrate having at least an exposed first surface containing silicon oxide and a second surface containing silicon or a silicon compound other than silicon oxide; a surface modification step of forming an etching selectivity-imparting film on at least a portion of the first surface and at least a portion of the second surface by a silylation treatment in which a silylating agent is brought into contact with the first surface and the second surface; and an etching step of selectively etching the second surface relative to the first surface using an etching agent after the surface modification step. 2. The method for treating a substrate according to 1., wherein the surface modification step involves performing a pretreatment before the silylation treatment, and the pretreatment includes a treatment for increasing the difference between a first water contact angle in the etching selectivity-imparting film on the first surface and a second water contact angle in the etching selectivity-imparting film on the second surface. 3. The method for treating a substrate according to 1. or 2. 3. The method for treating a substrate according to claim 1, wherein in the preparation step, the substrate contains a silicon compound other than silicon oxide on the second surface, and after the surface modification step, the etching step is carried out without carrying out an oxidation treatment of bringing an oxidizing agent into contact with the second surface. 4. The method for treating a substrate according to claim 1 or 2, wherein in the preparation step, the substrate contains silicon on the second surface, and after the surface modification step, the etching step is carried out by carrying out an oxidation treatment of bringing an oxidizing agent into contact with the second surface, and then carrying out the etching treatment. 5. The method for treating a substrate according to any one of claims 1 to 4, wherein in the surface modification step, a first water contact angle on the etching selectivity imparting film on the first surface is larger than a second water contact angle on the etching selectivity imparting film on the second surface. 6. The method for treating a substrate according to claim 5, wherein a difference between the first water contact angle and the second water contact angle is 5° or more.7. The method for treating a substrate according to any one of 1. to 6., comprising a cleaning step of cleaning the first surface and the second surface using a cleaning agent between the surface modification step and the etching step. 8. The method for treating a substrate according to 7., wherein the liquid temperature of the cleaning agent is 60°C or less. 9. The method for treating a substrate according to 7. or 8., wherein the cleaning agent comprises an aqueous cleaning solution and / or a rinse solution. 10. The method for treating a substrate according to any one of 7. to 9., wherein a cycle comprising at least the surface modification step, the cleaning step, and the etching step, in this order, is carried out two or more times. 11. The method for treating a substrate according to any one of 1. to 10., comprising a removal step of removing at least a portion of the etching selectivity-imparting film on the first surface after the etching step. 12. The method for treating a substrate according to 1. to 11. 13. A method for treating a substrate according to any one of 1. to 12., wherein a cycle including at least the surface modification step and the etching step, in this order, is carried out two or more times. 14. A method for treating a substrate according to any one of 1. to 12., wherein the etching selectivity-imparting film is formed in the silylation treatment using a silylation composition including the silylating agent and a catalytic compound. 15. A method for manufacturing a substrate, comprising each step of the method for treating a substrate according to any one of 1. to 13.

[0011] According to the present invention, there are provided a method for treating a substrate which exhibits good etching selectivity for a silicon nitride-containing second surface relative to a silicon oxide-containing first surface and excellent liquid drainage, and a method for manufacturing a substrate using the same.

[0012] Fig. 1 is a process cross-sectional view schematically showing each step of the substrate treatment method of the present embodiment. Fig. 2 is a process cross-sectional view schematically showing each step of the substrate treatment method of the present embodiment. Fig. 3 shows an example of a process flow of the substrate treatment method of the present embodiment.

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by similar reference numerals, and descriptions thereof will be omitted where appropriate. Furthermore, the drawings are schematic diagrams and do not correspond to actual dimensional proportions.

[0014] <Substrate Treatment Method> An outline of the substrate treatment method of this embodiment will be described.

[0015] The method for treating a substrate of this embodiment includes: a preparation step of preparing a substrate having at least an exposed first surface containing silicon oxide and a second surface containing silicon nitride; a surface modification step of forming an etching selectivity-imparting film on at least a portion of the first surface and at least a portion of the second surface by a silylation treatment in which a silylating agent is brought into contact with the first surface and the second surface; and an etching step of selectively etching the second surface relative to the first surface using an etching agent after the surface modification step.

[0016] According to the inventors' findings, it is possible to form a film (etching selectivity-imparting film) that imparts good etching selectivity to a second surface containing silicon nitride relative to a first surface containing silicon oxide by utilizing the difference in reactivity with a silylation agent. This not only imparts etching selectivity to the second surface relative to the first surface, but also improves drainage on the first and second surfaces compared to when no silylation treatment is performed. By improving drainage, drainage during cleaning processes, drying processes, and the like can be promoted. In this specification, "etching selectivity" refers to the ability to ensure that the etching amount of the first surface is less than the etching amount of the second surface during an etching process. Furthermore, silicon compounds other than silicon oxide (e.g., silicon nitride, silicon (polysilicon), silicon germanium, etc.) are more easily etched by oxidation. Further research by the inventors has revealed that contact with an oxidizing agent, described below, maintains the etching selectivity-imparting film formed on the first surface, while oxidizing the second surface even when an etching selectivity-imparting film is formed on the first surface. Therefore, by carrying out an oxidation treatment using the above-mentioned oxidizing agent before the etching treatment, even if the second surface is made of a material other than silicon nitride, it is possible to perform etching in a suitable and selective manner.

[0017] In this specification, the terms "etching selectivity-imparting film" and "water-repellent film" refer to both a compound having a silyl group derived from a silylating agent chemically bonded to a surface having silicon atoms, and a group of such compounds, regardless of whether or not the compounds interact with each other or are bonded to each other. The water-repellent film may also contain a compound derived from a silylating agent physically bonded (adsorbed, attached, etc.) to the surface having silicon atoms. The bond does not necessarily have to be direct, and may also be formed via another element, a substituent, or the like.

[0018] (Water repellency) In this specification, the water repellency is defined as the water contact angle obtained by the following measurement. Details of cleaning and drying before each measurement will be described later. First, the substrate was placed horizontally with the smooth surface having the desired silicon element facing up, and a 2 μl droplet of pure water was placed on the surface. Next, in accordance with JIS R 3257:1999 "Test method for wettability of substrate glass surfaces," the angle between the water droplet and the substrate was measured using a contact angle meter (CA-X model, manufactured by Kyowa Interface Science Co., Ltd.), and the obtained value was taken as the water contact angle. The temperature during the measurement was room temperature (25° C.).

[0019] (Drainage) In this specification, the drainage is measured using the water receding angle obtained by the following measurement on a smooth substrate immediately before etching. When the water receding angle is 10° or more, drainage is considered good, and when it is less than 10°, drainage is considered poor. First, the substrate was placed horizontally with the silylated surface facing up, and 30 μl of pure water was dropped onto it at room temperature of 25° C. Next, the pure water was sucked in at a rate of 6 μl / sec, and the angle between the water droplet and the substrate while the droplet was decreasing in size was measured using the contact angle meter, and this value was taken as the water receding angle (°).

[0020] Each step included in the method for treating a substrate will be described in detail below.

[0021] An example of a substrate processing method according to the present embodiment includes a preparation step, a surface modification step, and an etching step, and will be described with reference to Figures 1 and 2. Figures 1 and 2 are cross-sectional views schematically illustrating the steps of the substrate processing method.

[0022] (Preparation Step) In the preparation step, as shown in FIG. 1, a substrate 1 having a first surface 11 and a second surface 12 on its surfaces is prepared.

[0023] The material of the substrate 1 is not particularly limited as long as it is a substrate used in a semiconductor manufacturing process, and may be made of, for example, silicon, silicon carbide, a plurality of components containing silicon element, sapphire, various compound semiconductors, etc. Furthermore, the substrate 1 may be, for example, a wafer.

[0024] The substrate 1 may have a relief structure (not shown) formed on the substrate surface. The relief structure may be, for example, a three-dimensional structure having one or more structures arranged along the vertical direction of the substrate surface 1a and / or one or more structures arranged along a horizontal direction perpendicular to the vertical direction. Examples of such three-dimensional structures may constitute at least a part of a logic device, a memory device, a gate electrode, etc., such as a FinFET, a nanowire FET, a nanosheet FET, or other multi-gate FET, a three-dimensional memory cell, etc.

[0025] The first surface 11 and the second surface 12 may be disposed along the planar direction of the substrate surface 1 a, or along a direction perpendicular to the substrate surface 1 a. According to this embodiment, not only two-dimensional selective processing on a plane but also three-dimensional selective processing on a three-dimensional structure (three-dimensional film formation, three-dimensional etching, etc.) is possible.

[0026] The first surface 11 and the second surface 12 may be formed adjacent to each other, or may be formed spaced apart from each other. The first surface 11 and the second surface 12 may each be composed of one region or two or more regions. In each surface, the multiple regions may be formed spaced apart from each other.

[0027] The first surface 11 contains silicon oxide. The other, second surface 12, contains silicon or a silicon compound other than silicon oxide. In this specification, silicon refers to single-crystal silicon or polysilicon. The silicon compound other than silicon oxide may be a compound of Si and at least one element selected from the group consisting of N, C, and a metal element. The metal element may be any metal element or semi-metal element typically used in semiconductor materials, such as W, Co, Al, Ni, Ru, Cu, Ge, Ti, Hf, and Ta. Examples of silicon compounds containing N and / or C include compounds such as silicon nitride, silicon carbide, and silicon carbonitride, as well as compounds of these compounds with the above metal elements. Among the above, silicon compounds containing N, such as silicon nitride, are preferred from the viewpoint of ease of etching. Furthermore, when performing the oxidation treatment described below before the etching treatment, the second surface 12 preferably contains silicon or a compound of Si and at least one element selected from the group consisting of N, C, and a metal element, and more preferably contains silicon or a silicon compound having at least one of C and a metal element. In the case of a naturally oxidized second surface 12, if the second surface 12 is contacted with a silylation agent after removing oxygen elements derived from natural oxidation in the surface modification process described below, the naturally oxidized surface may be used as a surface in a non-naturally oxidized state in the preparation process (e.g., a naturally oxidized silicon surface may be prepared as a silicon surface). The first surface 11 and the second surface 12 may be the surface of a component made of the above materials, or the surface of a film formed from the above materials (e.g., a film containing an oxide of Si or a nitride of Si). Furthermore, elements other than the above materials may be included as long as they do not affect silylation. Examples include H, O, N, C, P, B, and Al. The above-described film compositions are merely representative, and the stoichiometric ratios do not have to be integer ratios as described. Specifically, they are not limited to Si:O=1:1 or Si:N=1:1.

[0028] The water repellency of each of the first surface 11 and the second surface 12 is typically an inherent property of the compositional materials that make up the surfaces, but it can be adjusted by pretreatment and silylation treatment, as described below. For example, silylation treatment tends to improve the original water repellency (e.g., water contact angle), and pretreatment can strengthen or weaken the effect of the silylation treatment. Because the above tendency differs depending on the compositional materials that make up the surfaces, a desired etching selectivity-imparting film (water-repellent film) can be formed by considering the combination of each treatment and the water repellency immediately after these treatments. Note that even when a water-repellent film is formed on the surface by the silylation treatment of the first surface 11 or the second surface 12, and "water repellency of the surface" actually means "water repellency of the water-repellent film," the terms "water repellency of the first surface" and "water repellency of the second surface" will be used.

[0029] Substrate 1 in the first surface 11 and second surface 12, and in the peripheral regions below first surface 11 and second surface 12, may contain a small amount of one or more dopants (e.g., P, N, B, Al, etc.) used for n-type source / drain and p-type source / drain. The dopants can affect the electrical properties when added in small amounts relative to the Si element content, and therefore, it is presumed that the dopants will not affect the silylation at first surface 11 or second surface 12 as long as they are contained in an amount sufficient to function as a dopant.

[0030] The substrate 1 may further have a third surface and / or a fourth surface (not shown) on the substrate surface 1a. The third surface contains Si and has a chemical composition different from that of the first surface 11 and the second surface 12. The fourth surface does not contain Si and is composed of, for example, amorphous carbon, elements such as W, Co, Al, Ni, Ru, Cu, Ti, and Ta, or compounds, oxides, or nitrides of these elements. The fourth surface may be a film surface of a high-k film. The third surface and the fourth surface may be adjacent to the first surface 11 and / or the second surface 12, respectively, or may be formed separately from each other. Furthermore, the third surface and the fourth surface may each be composed of one region or two or more regions.

[0031] (Surface Modification Step) The surface modification step includes a silylation treatment of the substrate surface. As described above, the silylation treatment can form etching selectivity-imparting films (water-repellent films 21 and 22) on the first surface 11 and the second surface 12 of the substrate. In other words, it is possible to gently improve the water repellency of the second surface 12, and then make the water repellency of the first surface 11 higher than that of the second surface 12. In this case, a separate treatment such as a pretreatment may be performed before or after the silylation treatment in order to achieve the desired water repellency of the first surface 11 and the second surface 12.

[0032] An example of the surface modification step involves pretreating the substrate 1 shown in FIG. 1 and then performing a silylation treatment as shown in FIG. 2. In this specification, the pretreatment / silylation treatment may be referred to as pretreatment A / silylation treatment B, or treatment A / treatment B, respectively. Note that some or all of these treatments A to B may be performed using a wet process. Furthermore, the above treatments A to B may treat the first surface 11 and the second surface 12 separately or simultaneously, but simultaneous treatment as shown in FIG. 1 is preferred for simplicity. Furthermore, if good results can be obtained with silylation treatment B without pretreatment A, pretreatment A may not be performed.

[0033] In the surface modification step, when pretreatment A is performed before silylation treatment B, pretreatment A may include a treatment for increasing the difference between a first water contact angle in the etching selectivity-imparting film (water-repellent film 21) on the first surface 11 and a second water contact angle in the etching selectivity-imparting film (water-repellent film 22) on the second surface 12.

[0034] Specific examples of pretreatment A may include treatment A-1 for removing at least a portion of the native oxide film on the surface and / or treatment A-2 for bonding OH to at least a portion of the Si elements on the surface.

[0035] Pretreatment A may be performed on at least the first surface 11 , but may also be performed on the first surface 11 and the second surface 12 .

[0036] Treatment A-1 is not particularly limited as long as it is a treatment capable of removing a native oxide film. Typically, a native oxide film forms on the surface of silicon oxide or the like during the semiconductor manufacturing process. Treatment A-1 is preferable because it can remove this native oxide film. Treatment A-1 is not necessary for surfaces on which a native oxide film does not form, but may be performed as part of a cleaning process. Specific methods for treatment A-1 include, for example, contacting the first surface 11 and the second surface 12 with hydrogen fluoride (HF) or contacting the first surface 11 and the second surface 12 with a diluted aqueous hydrogen fluoride solution, i.e., hydrofluoric acid (DHF). The specific contacting method may be a known method, such as a method similar to the silylation treatment B described below. After treatment A-1, a cleaning treatment using a cleaning agent described below may be performed before silylation treatment B.

[0037] Treatment A-2 is not particularly limited as long as it is a method for forming OH groups on the surface of the first surface 11, but examples include a method of contacting at least the first surface 11 with an oxidizing agent containing oxygen elements. Furthermore, treatment A-2 may also be applied to the second surface 12 when treating the first surface 11, as long as it does not impair etching selectivity. OH groups are less likely to form on the second surface 12 than on the first surface 11, but if the oxidizing power of treatment A-2 is strong, more OH groups than necessary may also be formed on the second surface 12, and the water repellency obtained by the subsequent silylation treatment B may not be within the desired range. For this reason, it is desirable to use an oxidizing agent for use in treatment A-2 that has an oxidizing power that can be easily adjusted. As the oxidizing agent, it is preferable to use a liquid oxidizing agent because the strength of the oxidation can be easily adjusted. As the liquid oxidizing agent, for example, H ２ O ２ and / or ozone water. ２ O ２ The solution containing, for example, a cleaning agent (H ２ O ２ and ammonium hydroxide alkaline mixture (SC-1 liquid) and H ２ O ２ Acidic mixture of acetic acid and hydrochloric acid (SC-2 solution, etc.), ２ O ２Examples of the oxidizing agent include an aqueous solution. A gas containing oxygen may be used as the oxidizing agent as long as it does not excessively form OH groups on the second surface 12. The specific contacting method may be a known method, such as a method similar to the silylation treatment B described below. Before the treatment A-2, treatment A-1 may be performed, if necessary, to remove the native oxide film. After the treatment A-2, a cleaning treatment using a cleaning agent described below may be performed before the silylation treatment B.

[0038] As shown in FIG. 2( a), silylation treatment B is a treatment in which a silylating agent, described below, is brought into contact with at least the first surface 11 and the second surface 12. In silylation treatment B, a silylating agent may be used alone, or a silylation composition containing a silylating agent and a solvent or diluent gas, or a silylation composition containing a silylating agent and a catalytic compound, may be used. The silylation agent or silylation composition may be used in a liquid or gaseous state. From the viewpoint of easily improving the water repellency of the first surface 11 and the second surface 12, it is preferable to supply the silylation composition containing a silylating agent and a catalytic compound in liquid form.

[0039] In the case of a wet process, a liquid of the silylation agent 20 or silylation composition 20 is supplied to the first surface 11 and the second surface 12. A known supply method can be used; for example, when supplying in a liquid state, a single-wafer method such as spin coating or a batch method such as immersion can be used. The liquid temperature of the silylation agent 20 or silylation composition 20 at this time may be lower than the boiling point of the silylation agent, and may be, for example, 10 to 60°C. It may also be preferably 10 to 30°C, and more preferably 10 to 29°C. When supplying the silylation agent 20 or silylation composition 20 as a vapor and turning it into a liquid after contacting the first surface 11 and the second surface 12, a known vapor injection method can be used.

[0040] In the case of a dry process, the silylation agent is supplied as a gas to the first surface 11 and the second surface 12. A known method can be used for the supply method, but for example, a method in which the silylation agent is gasified in advance using a vaporizer or the like and then supplied, ２In addition, two or more kinds of gases may be supplied simultaneously or may be mixed in advance and supplied.

[0041] Silylation treatment B can improve the water repellency of the first surface 11 and the second surface 12, with the water repellency of the first surface 11 being relatively higher than that of the second surface 12. Silylation treatment B improves the water repellency of the first surface 11 by forming a structure in which silyl groups derived from the silylating agent are chemically bonded to OH groups on the first surface 11, i.e., a water-repellent film. A water-repellent film is also formed on the second surface 12, although the water repellency is not as high as that of the first surface 11.

[0042] 2(b), a water-repellent film 21 may be formed on the first surface 11, and a water-repellent film 22 may be formed on the second surface 12. The water-repellent film 21 and the water-repellent film 22 may each be formed by a film that covers at least a part of or the entire surface.

[0043] If pretreatment A can increase the number of reaction sites with the silylating agent on the first surface 11 relative to the second surface 12, then silylation treatment B can relatively accelerate the silylation reaction on the first surface 11. In the case of a wet process, treatment under oxygen-containing air can also slightly oxidize the surface of the second surface 12, which is thought to generate OH groups (Si-OH bonds), which are reaction sites with the silylation agent. The aforementioned pretreatment A-1 can remove OH groups on the second surface 12, thereby suppressing the reaction between the second surface 12 and the silylation agent. This makes it possible to relatively accelerate the silylation reaction on the first surface 11. Furthermore, increasing the number of Si-OH bonds (OH groups) on the first surface 11 through pretreatment A-2 or the like is advantageous because it makes it easier to form a water-repellent film. In this case, as described above, adjusting the oxidizing power can suppress the formation of OH groups on the second surface 12.

[0044] If necessary, known means such as heating, decompression, or drying may be applied to the silylation treatment B to promote the silylation reaction between the silylating agent and the surface OH groups.

[0045] Furthermore, after the surface treatment step, in other words, immediately before the etching step, when the value (°) of the first water contact angle of the first surface 11 is Q1 and the value (°) of the second water contact angle of the second surface 12 is Q2, it is preferable to perform each treatment so that Q1 > Q2. The larger the difference, the higher the water repellency of the first surface 11 relative to the water repellency of the second surface 12, and therefore it is considered that an etching selectivity-imparting film with excellent etching selectivity is formed at least on the first surface 11.

[0046] Furthermore, the difference between Q1 and Q2 is preferably 5° or more, more preferably 10° or more, and even more preferably 20° or more. By setting the difference between Q1 and Q2 within the above range, it becomes easier to improve the etching selectivity in the etching step described below.

[0047] Furthermore, Q1 is preferably 65° or greater. By setting Q1 within the above range, etching selectivity is likely to be improved. It may be more preferably 70° or greater, and even more preferably 75° or greater. Furthermore, Q1 of 88° or greater is preferred because it can protect the first surface 11 from etching even when the etching time is 5 minutes. Furthermore, Q2 is not particularly limited as long as it satisfies Q1 > Q2 and does not impair the etching selectivity. For example, a value less than 63° is preferred because it is likely to improve etching selectivity. It may be more preferably 60° or less, and even more preferably 58° or less. The lower limit of Q2 is not particularly limited, but it may be, for example, 10° or greater, preferably 20° or greater, more preferably 30° or greater, and even more preferably 40° or greater. Furthermore, when the first surface 11 and the second surface 12 are simultaneously subjected to a surface modification treatment, the value of Q2 tends to increase as the value of Q1 increases, which may in turn decrease the etching selectivity. For example, it is preferred to perform the surface modification treatment so that Q2 / Q1 < 0.75. The Q2 / Q1 ratio is more preferably 0.70 or less, and even more preferably 0.68 or less. The lower limit is not particularly limited, but may be, for example, 0.05 or more. When the Q2 / Q1 value is higher than the above, the etching selectivity may be improved by performing an oxidation treatment before the etching treatment described below.

[0048] The surface modification step may optionally include a cleaning step in which a cleaning treatment is performed using a cleaning agent to clean at least a portion of the second surface 12 or the water-repellent film 22 formed on the second surface 12. For example, the cleaning treatment may be performed between the surface modification step and the etching step, but is not limited to this. By using a cleaning agent, impurities and unreacted silylation agent adhering to the first surface 11, the second surface 12, etc. can be washed away. Furthermore, when at least a portion of the treatments A to B are performed using a wet process, one or more cleaning treatments can be performed between each of the treatments A to B or between the individual treatments included in the treatments A to B. In the case of multiple cleaning treatments, the type of cleaning agent may be changed for each treatment.

[0049] The cleaning material may include an aqueous cleaning solution and / or a rinse solution.

[0050] The aqueous cleaning solution is not particularly limited as long as it does not remove the water-repellent film 21 formed on the first surface 11. Examples include water, alcohol, an aqueous hydrogen peroxide solution, and ozone water. These may be used alone or in combination of two or more.

[0051] Like the aqueous cleaning solution, the rinse solution is not particularly limited as long as it does not remove the water-repellent film 21 formed on the first surface 11. A cleaning agent different from that used in the aqueous cleaning solution can be used as the rinse solution, and examples thereof include water, an organic solvent, a mixture thereof, or a mixture of these with at least one of an acid, an alkali, a surfactant, and an oxidizing agent. Examples of organic solvents used in the rinse solution include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide-based solvents, alcohols, polyhydric alcohol derivatives, and nitrogen-containing solvents. Among these, it is preferable to use at least one organic solvent selected from alcohols having 3 or fewer carbon atoms, such as methanol, 1-propanol, and 2-propanol (isopropanol).

[0052] The liquid temperature of the cleaning agent is not particularly limited, but may be, for example, 60° C. or less, 40° C. or less, or 30° C. or less, thereby preventing a decrease in the water repellency of the silylation-treated surface.

[0053] In this embodiment, the method of contacting the cleaning agent is not particularly limited, but examples thereof include immersion, application methods such as spin coating and spray coating, and vapor contact.

[0054] The surface modification step may include a drying treatment, if necessary. When at least a part of the treatments A and B is performed by a wet process, one or more drying treatments may be performed between the treatments A and B or between the individual treatments included in the treatments A and B.

[0055] (Etching Step) In the etching step, after the surface modification step, etching is selectively performed on the second surface 12 shown in Fig. 2(b) . Before the etching step, an oxidation treatment, which will be described later, may be performed.

[0056] When etching is performed, etching of the first surface 11 is suppressed, but etching of the second surface 12 progresses more rapidly than that of the first surface 11. This makes it possible to selectively etch the second surface 12 compared to the first surface 11. Although the detailed mechanism is unclear, it is presumed that the water-repellent film 21 on the first surface 11 acts as a shielding material for the etching agent, so that etching of the first surface 11 is suppressed more than etching of the second surface 12.

[0057] (Oxidation Treatment) The oxidation treatment is performed before the etching treatment. At least a portion of the second surface 12 after the surface modification process is oxidized. The oxidized second surface 12 is more susceptible to etching, thereby improving etching selectivity. This is particularly suitable when the second surface 12 contains silicon or a compound of Si, C, and at least one element selected from the group consisting of metal elements. The oxidation treatment involves contacting the second surface 12 after the surface modification process with an oxidizing agent to oxidize at least a portion of the second surface 12. By performing the oxidation treatment to a degree that does not significantly impair the etching selectivity of the etching selectivity-imparting film on the first surface 11, the first surface 11 and the second surface 12 after the surface modification process can be simultaneously contacted with the oxidizing agent. For example, the oxidation treatment may be performed so that the water contact angle of the water-repellent film 21 on the first surface 11 of the present disclosure remains at 65° or greater after the oxidation treatment. By maintaining the water contact angle within this range, etching selectivity is more easily improved. The water contact angle may be more preferably 70° or greater, and even more preferably 75° or greater. When the second surface 12 is subjected to the oxidation treatment, at least a portion of the second surface 12 becomes silicon oxide. However, since the silicon oxide in this case is a precursor that is removed by the etching treatment, the precursor formed on the second surface 12 by the oxidation treatment is treated as the second surface 12. The oxidizing agent used may be a liquid oxidizing agent similar to that used in the above-mentioned treatment A-2, as long as it does not impair the etching selectivity on the first surface 11. For example, H ２ O ２ and / or ozone water. ２ O ２ The solution containing, for example, a cleaning agent (H ２ O ２ and ammonium hydroxide alkaline mixture (SC-1 liquid) and H ２ O ２ Acidic mixture of acetic acid and hydrochloric acid (SC-2 solution, etc.), ２ O ２Examples of suitable oxidizing agents include aqueous solutions. These oxidizing agents may be contacted at a concentration that does not impair the etching selectivity on the first surface 11. The specific contacting method may be a known method, such as the same method as in the silylation treatment B described above. Furthermore, after the oxidation treatment, a cleaning treatment or a drying treatment may be performed. Furthermore, when performing the oxidation treatment, if the silylating agent remains on the substrate in some state, an unintended reaction with the oxidizing agent may occur. Therefore, it is desirable to perform a cleaning step at least once after the silylation treatment B in the surface modification step described above. Furthermore, as described above, the first surface 11 and the second surface 12 after the surface modification step have good drainage properties, so the cleaning step can be performed suitably.

[0058] The etching process is not particularly limited as long as it can etch the second surface 12, and a known dry etching method or wet etching method can be selected. It is also preferable to perform various etching processes using an etching agent. In the case of a gas, for example, HF gas, HCl gas, or Cl gas is used. ２ Gas, F ２ gas, interhalogen gas (e.g., ClF ３ Gas, IF ７ In the case of liquids, HF, NH ４ F, N.H. ４ HF ２ , H ３ P.O. ４ , and H ２ SO ４ The etching agent may be heated or may be in the form of plasma or radicals.

[0059] If the water-repellent film 21 (etching selectivity-imparting film) remaining on the first surface 11 after the etching step is unnecessary, a removal process may be performed to remove at least a portion of the water-repellent film 21. The removal method is not particularly limited as long as it is a known method capable of removing silylated groups. Examples include light (ultraviolet) irradiation, heat treatment, ozone exposure, plasma irradiation, and corona discharge. Removal by a wet process is also possible, such as contact with an ammonium hydroxide aqueous solution, a tetramethylammonium aqueous solution, a hydrochloric acid aqueous solution, or a sulfuric acid aqueous solution. Furthermore, by appropriately controlling the etching conditions, the etchant used in the etching step may be used in the removal process. This can simplify the process.

[0060] 3(a) to 3(e) show process flow diagrams of an example of a substrate treatment method according to this embodiment. Note that the present invention is not limited to the process flow described below. In the substrate treatment method of FIG. 3(a), a silylation treatment is performed as the surface treatment step, followed by an etching treatment as the etching step. In the substrate treatment method of FIG. 3(b), a pretreatment A and a silylation treatment are performed as the surface treatment step, followed by etching as the etching step. In the substrate treatment method of FIG. 3(c), a pretreatment A and a silylation treatment are performed as the surface treatment step, followed by an oxidation treatment and etching as the etching step. Note that, if necessary, a cleaning treatment can be performed between each of the treatments shown in FIGS. 3(a) to 3(c). While FIG. 3(c) shows a flow including pretreatment A, a flow without pretreatment A may also be used. Note that, in the substrate treatment method, a cycle including at least a surface modification step and an etching step, in this order, may be performed two or more times. Also, in the substrate treatment method, a cycle including at least a surface modification step, a cleaning step, and an etching step, in this order, may be performed two or more times. This cycle process can increase the etching amount while maintaining the etching selectivity. In another embodiment, in a substrate treatment method in which the above cycle is performed two or more times, the densification of the first surface 11 is promoted by continuing the same silylation treatment. Therefore, the time for the nth silylation treatment may be shorter than the time for the (n-1)th silylation treatment, where n is an integer greater than or equal to 2. The shortened silylation treatment may be performed only in the second treatment, all subsequent treatments, or at least one subsequent treatment. In a substrate treatment method in which the above cycle is performed two or more times, the first surface treatment step may include a pretreatment, but at least one of the surface modification steps from the second treatment onward may not include a pretreatment. An example of a process flow for this cycle is shown in FIG. 3(d). If both the pretreatment A and the etching treatment are either oxidative or non-oxidative, the etching treatment doubles as pretreatment A, making it possible to omit pretreatment A from the second treatment onward. Another example of a process flow for this cycle is shown in FIG. 3(e).When one of the pretreatment A and the etching treatment is an oxidative treatment and the other is a non-oxidative treatment, it is preferable to carry out a cleaning treatment after the etching treatment and before the pretreatment A. The above-mentioned "oxidative treatment" includes, for example, treatment using the material used in the pretreatment A-2 or oxidation treatment, etching treatment involving oxidation, etc. The "non-oxidative treatment" includes, for example, treatment using the material used in the pretreatment A-1, etching treatment not involving oxidation, etc.

[0061] The method for manufacturing a substrate of this embodiment includes a step of obtaining a substrate that has been subjected to each step in the above-described method for treating a substrate. By the method for manufacturing a substrate, a desired semiconductor wafer or semiconductor device can be obtained.

[0062] <Silylating Agent> The silylating agent used in the silylation treatment in the above-described method for treating a substrate and the silylation composition containing the silylating agent will now be described.

[0063] Known silylating agents can be used as the silylating agent. Examples of the silylating agent include silicon compounds represented by the following general formula [1]. These may be used alone or in combination of two or more kinds. When two or more kinds are combined, they may be referred to as a "silylated composition." When two or more kinds are combined, the R １ These may be used in combination with each other having the same number of carbon atoms, or in combination with each other having different numbers of carbon atoms.

[0064] R １ ａ Si(H) ｂ X ４－ａ－ｂ [1]

[0065] In the above general formula [1], R １ are each independently an organic group containing a hydrocarbon group having 1 to 18 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms; each X is independently a monovalent organic group in which the element bonded to the Si atom is nitrogen, oxygen, carbon, or halogen; a is an integer of 1 to 3; b is an integer of 0 to 2; and the sum of a and b is 1 to 3.

[0066] R in the above general formula [1] １ may contain not only hydrogen, carbon, nitrogen, oxygen, and fluorine elements, but also silicon, sulfur, and halogen elements (other than fluorine). １ R in the above general formula [1] may contain an unsaturated bond, an aromatic ring, or a cyclic structure. １ For example, each independently represents C ｅ H ２ｅ＋１ (e=1 to 18), and C ｆ F ２ｆ＋１ CH ２ CH ２ (f=1 to 8). Among these, it is particularly preferable to use a silicon compound having a trialkylsilyl group. １ When R contains a silicon element, the general formula [1] may have a structure represented by the following general formula [1-1]: １ ｍ X ３－ｍ－ｎ (H) ｎ Si-(CH ２ ) ｐ -Si(H) ｎ X ３－ｍ－ｎ R １ ｍ [1-1] In the above general formula [1-1], R １ (However, this R １ does not contain silicon element) and X are the same as those in the above general formula [1], m is an integer of 1 to 2, n is an integer of 0 to 1, the sum of m and n is 1 to 2, p is an integer of 1 to 18, and -(CH ２ ) ｐ The methylene chain represented by - may be substituted with a halogen.

[0067] In X in the general formula [1], the monovalent organic group in which the element bonded to the Si element is nitrogen, oxygen, or carbon may contain not only hydrogen, carbon, nitrogen, or oxygen, but also silicon, sulfur, a halogen element, etc. Examples of the monovalent organic group in which the element bonded to the Si element is nitrogen include, for example, an isocyanate group, an amino group, a dialkylamino group, an isothiocyanate group, an azide group, an acetamide group, and -NHC(=O)CF３ , -N(CH ３ )C(=O)CH ３ , -N(CH ３ )C(=O)CF ３ , -N=C(CH ３ )OSi(CH ３ ) ３ , -N=C(CF ３ )OSi(CH ３ ) ３ , -NHC(=O)-OSi(CH ３ ) ３ , -NHC(=O)-NH-Si(CH ３ ) ３ , an imidazole ring, a triazole ring, a tetrazole ring, an oxazolidinone ring, a morpholine ring, —NH—C(═O)—Si(CH ３ ) ３ , -N(S(=O) ２ R ４ ) ２ (where R ４ are each independently a group selected from the group consisting of a monovalent hydrocarbon group having 1 to 8 carbon atoms, in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and fluorine atoms), and a substituent having a structure of the following general formula [1-2] (In the above general formula [1-2], R ５ are each independently a divalent hydrocarbon group having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms), -N=C(NR ６ ２ ) ２ , -N=C(NR ６ ２ ) R ６ (where R ６ are each independently a hydrogen group, a —C≡N group, or —NO ２ and a hydrocarbon group in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and the hydrocarbon group may have an oxygen atom and / or a nitrogen atom. ａ１ ) (R ａ２ ) (wherein the above R ａ１ represents a hydrogen atom or a saturated or unsaturated alkyl group, and R ａ２represents a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, or a saturated or unsaturated heterocycloalkyl group. ａ１ and R ａ２ may be bonded to each other to form a saturated or unsaturated heterocycloalkyl group having a nitrogen atom. ａ３ )-Si(R ａ４ ) (R ａ５ ) (R ａ６ ) (wherein the above R ａ３ represents a hydrogen atom, a hydrocarbon group having 1 to 4 carbon atoms, a trimethylsilyl group, or a dimethylsilyl group, and ａ４ , R ａ５ and R ａ６ each independently represents a hydrogen atom or an organic group, R ａ４ , R ａ５ and R ａ６ The total number of carbon atoms contained in —N(R ａ７ )-C(=O)R ａ８ (Here, the above R ａ７ represents a hydrogen atom, a methyl group, a trimethylsilyl group, or a dimethylsilyl group, and R ａ８ represents a hydrogen atom, a saturated or unsaturated alkyl group, a fluorine-containing alkyl group, or a trialkylsilylamino group.

[0068] Examples of the silylating agent in which X in the general formula [1] is a monovalent organic group in which the element bonded to the Si element is nitrogen include CH ３ Si(NH ２ ) ３ , C ２ H ５ Si(NH ２ ) ３ , C ３ H ７ Si(NH ２ ) ３ , C ４ H ９ Si(NH ２ ) ３ , C ５ H １１ Si(NH ２ ) ３ , C ６ H １３ Si(NH ２ )３ 、C ７ H １５ H ２ ) ３ 、C ８ H １７ H ２ ) ３ 、C ９ H １９ H ２ ) ３ 、C １０ H ２１ H ２ ) ３ 、C １１ H ２３ H ２ ) ３ 、C １２ H ２５ H ２ ) ３ 、C １３ H ２７ H ２ ) ３ 、C １４ H ２９ H ２ ) ３ 、C １５ H ３１ H ２ ) ３ 、C １６ H ３３ H ２ ) ３ 、C １７ H ３５ H ２ ) ３ 、C １８ H ３７ H ２ ) ３ 、(CH ３ ) ２ H ２ ) ２ 、C ２ H ５ H ３ ) ２ ) ２ 、(C ２ H ５ ) ２ H ２ ) ２ 、C ３ H ７ H３ ) ２ ) ２ 、(C ３ H ７ ) ２ H ２ ) ２ 、C ４ H ９ H ３ ) ２ ) ２ 、(C ４ H ９ ) ２ H ２ ) ２ 、C ５ H １１ H ３ ) ２ ) ２ 、C ６ H １３ H ３ ) ２ ) ２ 、C ７ H １５ H ３ ) ２ ) ２ 、C ８ H １７ H ３ ) ２ ) ２ 、C ９ H １９ H ３ ) ２ ) ２ 、C １０ H ２１ H ３ ) ２ ) ２ 、C １１ H ２３ H ３ ) ２ ) ２ 、C １２ H ２５ H ３ ) ２ ) ２ 、C １３ H ２７ H ３ ) ２ ) ２ 、C １４ H ２９H ３ ) ２ ) ２ 、C １５ H ３１ H ３ ) ２ ) ２ 、C １６ H ３３ H ３ ) ２ ) ２ 、C １７ H ３５ H ３ ) ２ ) ２ 、C １８ H ３７ H ３ ) ２ ) ２ 、(CH ３ ) ３ H ２ 、C ２ H ５ H ３ ) ２ NH ２ 、(C ２ H ５ ) ２ H ３ )NH ２ 、(C ２ H ５ ) ３ H ２ 、C ３ H ７ H ３ ) ２ NH ２ 、(C ３ H ７ ) ２ H ３ )NH ２ 、(C ３ H ７ ) ３ H ２ 、C ４ H ９ H ３ ) ２ NH ２ 、(C ４ H ９ ) ３ H ２ 、C ５ H１１ H ３ ) ２ NH ２ 、C ６ H １３ H ３ ) ２ NH ２ 、C ７ H １５ H ３ ) ２ NH ２ 、C ８ H １７ H ３ ) ２ NH ２ 、C ９ H １９ H ３ ) ２ NH ２ 、C １０ H ２１ H ３ ) ２ NH ２ 、C １１ H ２３ H ３ ) ２ NH ２ 、C １２ H ２５ H ３ ) ２ NH ２ 、C １３ H ２７ H ３ ) ２ NH ２ 、C １４ H ２９ H ３ ) ２ NH ２ 、C １５ H ３１ H ３ ) ２ NH ２ 、C １６ H ３３ H ３ ) ２ NH ２ 、C １７ H ３５ H ３ ) ２ NH ２ 、C １８ H ３７H ３ ) ２ NH ２ 、(CH ３ ) ２ H. ２ CH ３ H ２ NH ２ 、(C ２ H ５ ) ２ H. ２ 、C ２ H ５ H ２ NH ２ 、C ２ H ５ H ３ )(H)NH ２ 、(C ３ H ７ ) ２ H. ２ 、C ３ H ７ H ２ NH ２ CF ３ CH ２ CH ２ H ２ ) ３ 、C ２ F ５ CH ２ CH ２ H ２ ) ３ 、C ３ F ７ CH ２ CH ２ H ２ ) ３ 、C ４ F ９ CH ２ CH ２ H ２ ) ３ 、C ５ F １１ CH ２ CH ２ H ２ ) ３ 、C ６ F １３ CH ２ CH ２ H ２ ) ３ 、C７ F １５ CH ２ CH ２ H ２ ) ３ 、C ８ F １７ CH ２ CH ２ H ２ ) ３ CF ３ CH ２ CH ２ H ３ ) ２ ) ２ 、C ２ F ５ CH ２ CH ２ H ３ ) ２ ) ２ 、C ３ F ７ CH ２ CH ２ H ３ ) ２ ) ２ 、C ４ F ９ CH ２ CH ２ H ３ ) ２ ) ２ 、C ５ F １１ CH ２ CH ２ H ３ ) ２ ) ２ 、C ６ F １３ CH ２ CH ２ H ３ ) ２ ) ２ 、C ７ F １５ CH ２ CH ２ H ３ ) ２ ) ２ 、C ８ F １７ CH ２ CH ２ H ３) ２ ) ２ CF ３ CH ２ CH ２ H ３ ) ２ NH ２ 、C ２ F ５ CH ２ CH ２ H ３ ) ２ NH ２ 、C ３ F ７ CH ２ CH ２ H ３ ) ２ NH ２ 、C ４ F ９ CH ２ CH ２ H ３ ) ２ NH ２ 、C ５ F １１ CH ２ CH ２ H ３ ) ２ NH ２ 、C ６ F １３ CH ２ CH ２ H ３ ) ２ NH ２ 、C ７ F １５ CH ２ CH ２ H ３ ) ２ NH ２ 、C ８ F １７ CH ２ CH ２ H ３ ) ２ NH ２ CF ３ CH ２ CH ２ H ３ )(H)NH ２, aminodimethylvinylsilane, aminodimethylphenylethylsilane, aminodimethylphenylsilane, aminomethyldiphenylsilane, aminodimethyl-t-butylsilane, etc. ２ group), -N=C=O, dialkylamino group (-N(CH ３ ) ２ , -N(C ２ H ５ ) ２ etc.), t-butylamino group, allylamino group, -N=C=S, -N ３ , -NHC(=O)CH ３ , -NHC(=O)CF ３ , -N(CH ３ )C(=O)CH ３ , -N(CH ３ )C(=O)CF ３ , -N=C(CH ３ )OSi(CH ３ ) ３ , -N=C(CF ３ )OSi(CH ３ ) ３ , -NHC(=O)-OSi(CH ３ ) ３ , -NHC(=O)-NH-Si(CH ３ ) ３ (e.g., N,N'-bis(trimethylsilyl)urea, etc.), imidazole ring (e.g., N-trimethylsilylimidazole, etc.), triazole ring (e.g., N-trimethylsilyltriazole, etc.), tetrazole ring, oxazolidinone ring, morpholine ring, -NH-C(=O)-Si(CH ３ ) ３ , -N(S(=O) ２ R ４ ) ２ (where R ４ are each independently a group selected from the group consisting of a monovalent hydrocarbon group having 1 to 8 carbon atoms, in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and fluorine atoms. For example, N-(trimethylsilyl)bis(trifluoromethanesulfonyl)imide, etc.), and a substituent having a structure of the following general formula [1-2]: (In the above general formula [1-2], R５ are each independently a divalent hydrocarbon group having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms. Examples include N-(trimethylsilyl)N,N-difluoromethane-1,3-bis(sulfonyl)imide, -N=C(NR ６ ２ ) ２ , -N=C(NR ６ ２ ) R ６ (where R ６ are each independently a hydrogen group, a —C≡N group, or —NO ２ and hydrocarbon groups in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and the hydrocarbon groups may have oxygen atoms and / or nitrogen atoms. For example, 2-trimethylsilyl-1,1,3,3-tetramethylguanidine, -N(R ａ１ ) R ａ２ (Here, the above R ａ１ represents a hydrogen atom or a saturated or unsaturated alkyl group, and R ａ２ represents a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, or a saturated or unsaturated heterocycloalkyl group. ａ１ and R ａ２ may be bonded to each other to form a saturated or unsaturated heterocycloalkyl group having a nitrogen atom. ａ３ )-Si(R ａ４ ) (R ａ５ ) (R ａ６ ) (wherein the above R ａ３ represents a hydrogen atom, a hydrocarbon group having 1 to 4 carbon atoms, a trimethylsilyl group, or a dimethylsilyl group, and ａ４ , R ａ５ and R ａ６ each independently represents a hydrogen atom or an organic group, R ａ４ , R ａ５ and R ａ６is 1 or more. For example, hexamethyldisilazane, N-methylhexamethyldisilazane, 1,1,3,3-tetramethyldisilazane, 1,3-dimethyldisilazane, 1,3-di-N-octyltetramethyldisilazane, 1,3-divinyltetramethyldisilazane, heptamethyldisilazane, N-allyl-N,N-bis(trimethylsilyl)amine, 1,3-diphenyltetramethyldisilazane, and 1,1,3,3-tetraphenyl-1,3-dimethyldisilazane, nonamethyltrisilazane, pentamethylethyldisilazane, pentamethylvinyldisilazane, pentamethylpropyldisilazane, pentamethylethyldisilazane, pentamethyl-t-butyldisilazane, pentamethylphenyldisilazane, trimethyltriethyldisilazane, and the like.), -N(R ａ７ )-C(=O)R ａ８ (Here, the above R ａ７ represents a hydrogen atom, a methyl group, a trimethylsilyl group, or a dimethylsilyl group, and R ａ８ represents a hydrogen atom, a saturated or unsaturated alkyl group, a fluorine-containing alkyl group, or a trialkylsilylamino group. Examples of such groups include N-trimethylsilylacetamide, N-trimethylsilyltrifluoroacetamide, N-methyl-N-trimethylsilylacetamide, N-methyl-N-trimethylsilyltrifluoroacetamide, bis(trimethylsilyl)acetamide, and bis(trimethylsilyl)trifluoroacetamide.

[0069] Examples of the silylating agent in which X in the general formula [1] is a monovalent organic group in which the element bonded to the Si element is oxygen include the amino group (—NH ２ group) by —O—C(═A)R ａ９ (wherein A is O, CHR ａ１０ , CHOR ａ１０ , C.R. ａ１０ R ａ１０ , or NR ａ１１ indicates R ａ９ , R ａ１０each independently represents a hydrogen atom, a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, a fluorine-containing alkyl group, a chlorine-containing alkyl group, a trialkylsilyl group, a trialkylsiloxy group, an alkoxy group, a phenyl group, a phenylethyl group, or an acetyl group, and ａ１１ represents a hydrogen atom, an alkyl group, or a trialkylsilyl group. Examples include trimethylsilyl acetate, dimethylsilyl acetate, monomethylsilyl acetate, trimethylsilyl trifluoroacetate, dimethylsilyl trifluoroacetate, monomethylsilyl trifluoroacetate, trimethylsilyl trichloroacetate, trimethylsilyl propionate, and trimethylsilyl butyrate.), —O—C(R ａ１２ ) = N(R ａ１３ ) (wherein the above R ａ１２ represents a hydrogen atom, a saturated or unsaturated alkyl group, a fluorine-containing alkyl group, or a trialkylsilylamino group; R ａ１３ represents a hydrogen atom, an alkyl group, or a trialkylsilyl group.), —O—C(R ａ１４ )=CH-C(=O)R ａ１５ (Here, the above R ａ１４ and R ａ１５ each independently represents a hydrogen atom or an organic group. For example, trimethylsilyloxy-3-penten-2-one, 2-trimethylsiloxypent-2-en-4-one, etc.), —OR ａ１６ (Here, the above R ａ１６ represents a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, or a fluorine-containing alkyl group. ａ１６ Examples of the silylating agent having the formula: ３ Si(OCH ３ ) ３ , C ２ H ５ Si(OCH ３ ) ３ , C ３ H ７ Si(OCH ３ ) ３ , C ４ H ９ Si(OCH ３ ) ３ , C ５H １１ Si(OCH ３ ) ３ 、C ６ H １３ Si(OCH ３ ) ３ 、C ７ H １５ Si(OCH ３ ) ３ 、C ８ H １７ Si(OCH ３ ) ３ 、C ９ H １９ Si(OCH ３ ) ３ 、C １０ H ２１ Si(OCH ３ ) ３ 、C １１ H ２３ Si(OCH ３ ) ３ 、C １２ H ２５ Si(OCH ３ ) ３ 、C １３ H ２７ Si(OCH ３ ) ３ 、C １４ H ２９ Si(OCH ３ ) ３ 、C １５ H ３１ Si(OCH ３ ) ３ 、C １６ H ３３ Si(OCH ３ ) ３ 、C １７ H ３５ Si(OCH ３ ) ３ 、C １８ H ３７ Si(OCH ３ ) ３ ,(H ３ ) ２ Si(OCH ３ ) ２ 、C ２ H ５ Si(H) ３ )(OCH ３ ) ２ 、(C２ H ５ ) ２ Si(OCH ３ ) ２ 、C ３ H ７ Si(H) ３ )(OCH ３ ) ２ 、(C ３ H ７ ) ２ Si(OCH ３ ) ２ 、C ４ H ９ Si(H) ３ )(OCH ３ ) ２ 、(C ４ H ９ ) ２ Si(OCH ３ ) ２ 、C ５ H １１ Si(H) ３ )(OCH ３ ) ２ 、C ６ H １３ Si(H) ３ )(OCH ３ ) ２ 、C ７ H １５ Si(H) ３ )(OCH ３ ) ２ 、C ８ H １７ Si(H) ３ )(OCH ３ ) ２ 、C ９ H １９ Si(H) ３ )(OCH ３ ) ２ 、C １０ H ２１ Si(H) ３ )(OCH ３ ) ２ 、C １１ H ２３ Si(H) ３ )(OCH ３ ) ２ 、C １２ H ２５ Si(H) ３ )(OCH ３) ２ 、C １３ H ２７ Si(H) ３ )(OCH ３ ) ２ 、C １４ H ２９ Si(H) ３ )(OCH ３ ) ２ 、C １５ H ３１ Si(H) ３ )(OCH ３ ) ２ 、C １６ H ３３ Si(H) ３ )(OCH ３ ) ２ 、C １７ H ３５ Si(H) ３ )(OCH ３ ) ２ 、C １８ H ３７ Si(H) ３ )(OCH ３ ) ２ ,(H ３ ) ３ SiOCH ３ 、C ２ H ５ Si(H) ３ ) ２ OCH ３ 、(C ２ H ５ ) ２ Si(H) ３ )OCH ３ 、(C ２ H ５ ) ３ SiOCH ３ 、C ３ H ７ Si(H) ３ ) ２ OCH ３ 、(C ３ H ７ ) ２ Si(H) ３ )OCH ３ 、(C ３ H ７ ) ３ SiOCH ３ 、C ４ H ９Si(H) ３ ) ２ OCH ３ 、(C ４ H ９ ) ３ SiOCH ３ 、C ５ H １１ Si(H) ３ ) ２ OCH ３ 、C ６ H １３ Si(H) ３ ) ２ OCH ３ 、C ７ H １５ Si(H) ３ ) ２ OCH ３ 、C ８ H １７ Si(H) ３ ) ２ OCH ３ 、C ９ H １９ Si(H) ３ ) ２ OCH ３ 、C １０ H ２１ Si(H) ３ ) ２ OCH ３ 、C １１ H ２３ Si(H) ３ ) ２ OCH ３ 、C １２ H ２５ Si(H) ３ ) ２ OCH ３ 、C １３ H ２７ Si(H) ３ ) ２ OCH ３ 、C １４ H ２９ Si(H) ３ ) ２ OCH ３ 、C １５ H ３１ Si(H) ３ ) ２ OCH ３ 、C １６ H ３３ Si(H)３ ) ２ OCH ３ 、C １７ H ３５ Si(CH ３ ) ２ OCH ３ 、C １８ H ３７ Si(CH ３ ) ２ OCH ３ 、(CH ３ ) ２ Si(H)OCH ３ 、CH ３ Si(H) ２ OCH ３ 、(C ２ H ５ ) ２ Si(H)OCH ３ [[ID=4)) ２ H ５ Si(H) ２ OCH ３ 、C ２ H ５ Si(CH ３ )(H)OCH ３ 、(C ３ H ７ ) ２ Si(H)OCH ３ and other alkylmethoxysilanes such as CF ３ CH ２ CH ２ Si(OCH ３ ) ３ 、C ２ F ５ CH ２ CH ２ Si(OCH ３ ) ３ 、C ３ F ７ CH ２ CH ２ Si(OCH ３ ) ３ 、C ４ F ９ CH ２ CH ２ Si(OCH ３ ) ３ 、C ５ F １１ CH ２ CH ２ Si(OCH３ ) ３ 、C ６ F １３ CH ２ CH ２ Si(OCH ３ ) ３ 、C ７ F １５ CH ２ CH ２ Si(OCH ３ ) ３ 、C ８ F １７ CH ２ CH ２ Si(OCH ３ ) ３ 、CF ３ CH ２ CH ２ Si(H) ３ )(OCH ３ ) ２ 、C ２ F ５ CH ２ CH ２ Si(H) ３ )(OCH ３ ) ２ 、C ３ F ７ CH ２ CH ２ Si(H) ３ )(OCH ３ ) ２ 、C ４ F ９ CH ２ CH ２ Si(H) ３ )(OCH ３ ) ２ 、C ５ F １１ CH ２ CH ２ Si(H) ３ )(OCH ３ ) ２ 、C ６ F １３ CH ２ CH ２ Si(H) ３ )(OCH ３ ) ２ 、C ７ F １５ CH ２ CH ２Si(H) ３ )(OCH ３ ) ２ 、C ８ F １７ CH ２ CH ２ Si(H) ３ )(OCH ３ ) ２ 、CF ３ CH ２ CH ２ Si(H) ３ ) ２ OCH ３ 、C ２ F ５ CH ２ CH ２ Si(H) ３ ) ２ OCH ３ 、C ３ F ７ CH ２ CH ２ Si(H) ３ ) ２ OCH ３ 、C ４ F ９ CH ２ CH ２ Si(H) ３ ) ２ OCH ３ 、C ５ F １１ CH ２ CH ２ Si(H) ３ ) ２ OCH ３ 、C ６ F １３ CH ２ CH ２ Si(H) ３ ) ２ OCH ３ 、C ７ F １５ CH ２ CH ２ Si(H) ３ ) ２ OCH ３ 、C ８ F １７ CH ２ CH ２ Si(H) ３ ) ２ OCH ３, C.F. ３ CH ２ CH ２ Si(CH ３ ) (H) OCH ３ or a compound in which the methyl group moiety of the methoxy group of the above methoxysilane is replaced with a monovalent hydrocarbon group having 2 to 18 carbon atoms in which some or all of the hydrogen atoms may be replaced with fluorine atoms), —O—S(═O) ２ -R ａ１７ (Here, the above R ａ１７ represents an alkyl group having 1 to 6 carbon atoms, a perfluoroalkyl group, a phenyl group, a tolyl group, —O—Si(CH ３ ) ３ For example, (e.g., trimethylsilyl sulfonate, trimethylsilyl benzene sulfonate, trimethylsilyl toluene sulfonate, trimethylsilyl trifluoromethane sulfonate, trimethylsilyl perfluorobutane sulfonate, bistrimethylsilyl sulfate, etc.), —O—P(—O—Si(CH ３ ) ３ ) ２ (for example, tristrimethylsilyl phosphite, etc.)

[0070] Furthermore, examples of the silylating agent in which X in the above general formula [1] is a monovalent organic group in which the element bonded to the Si element is oxygen include hexamethyldisiloxane, 1,3-diphenyl-1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, 1,1,1-triethyl-3,3-dimethyldisiloxane, 1,1,3,3-tetra-n-octyldimethyldisiloxane, bis(nonafluorohexyl)tetramethyldisiloxane, 1,3-bis(trifluoropropyl)tetramethyldisiloxane, 1,3-di-n-butyltetramethyldisiloxane, Siloxane, 1,3-di-n-octyltetramethyldisiloxane, 1,3-diethyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, hexa-n-butyldisiloxane, hexaethyldisiloxane, hexavinyldisiloxane, 1,1,3,3-tetraisopropyldisiloxane, vinylpentamethyldisiloxane, 1,3-bis(3-chloroisobutyl)tetramethyldisiloxane, hexaphenyldisiloxane, 1,1,1-triethyl-3,3,3-trimethyldisiloxane, 1,3-bis(chloromethyl)tetramethyldisiloxane Methyldisiloxane, 1,1,3,3-tetraphenyldimethyldisiloxane, pentamethyldisiloxane, 1,3-bis(3-chloropropyl)tetramethyldisiloxane, 1,3-dichloro-1,3-diphenyl-1,3-dimethyldisiloxane, n-butyl-1,1,3,3-tetramethyldisiloxane, 1,3-di-t-butyldisiloxane, vinyl-1,1,3,3-tetramethyldisiloxane, 1,1,1-trimethyl-3,3,3-triphenyldisiloxane, 3,3-diphenyltetramethyltrisiloxane, 3-phenylheptamethoxane Chiltrisiloxane, hexamethylcyclotrisiloxane, n-propylheptamethyltrisiloxane, 3-ethylheptamethyltrisiloxane, 3-(3,3,3-trifluoropropyl)heptamethyltrisiloxane, 1,1,3,5,5-pentaphenyl-1,3,5-trimethyltrisiloxane, octamethyltrisiloxane, 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane, hexaphenylcyclotrisiloxane, 1,1,1,5,5,5-hexamethyltrisiloxane, 3-phenyl-1,1,3,5,5-pentamethyltrisiloxane, 1,3,5-trivinyl-1,1,3,5,5-pentamethyltrisiloxane, 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane, 3-octylheptamethyltrisiloxane, 1,3,5-triphenyltrimethylcyclotrisiloxane, 1,1,1,3,3,5,5-heptamethyltrisiloxane, 1,1,3,3,5,5-hexamethyltrisiloxane, 1,1,1,5,5,5-hexaethyl-3-methyltrisiloxane, furfuryloxytrisiloxane, tetrakis(dimethylsiloxy)silane, 1,1,3,3,5,5,7,7-octamethyltetrasiloxane, diphenylsiloxane-dimethylsiloxane copolymer, 1,3-diphenyl-1,3-dimethyldisiloxane Also included are siloxane compounds such as methylsiloxane, octamethylcyclotetrasiloxane, 1,3-bis(trimethylsiloxy)-1,3-dimethyldisiloxane, tetra-n-propyltetramethylcyclotetrasiloxane, octaethylcyclotetrasiloxane, decamethyltetrasiloxane, dodecamethylcyclohexasiloxane, dodecamethylpentasiloxane, tetradecamethylhexasiloxane, hexaphenylcyclotrisiloxane, polydimethylsiloxane, polyoctadecylmethylsiloxane, decamethylcyclopentasiloxane, poly(3,3,3-trifluoropropylmethylsiloxane), trimethylsiloxy-terminated polydimethylsiloxane, and 1,1,3,3,5,5,7,7,9,9-decamethylpentasiloxane.

[0071] Examples of the silylating agent in which X in the general formula [1] is a monovalent organic group in which the element bonded to the Si element is carbon include the amino group (—NH ２ group) to -C(S(=O) ２ R ７ ) ３ (where R ７ are each independently a group selected from the group consisting of monovalent hydrocarbon groups having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and fluorine atoms. Examples include those in which hydrogen atoms are replaced by (trimethylsilyl)tris(trifluoromethanesulfonyl)methide, etc.

[0072] Furthermore, examples of the silylating agent in which X in the general formula [1] is a monovalent organic group in which the element bonded to the Si element is halogen include the amino group (—NH ２ group) is replaced with a chloro group, a bromo group, or an iodo group (for example, chlorotrimethylsilane, bromotrimethylsilane, etc.).

[0073] The silylating agent may contain a cyclic silazane compound, such as cyclic disilazane compounds like 2,2,5,5-tetramethyl-2,5-disila-1-azacyclopentane and 2,2,6,6-tetramethyl-2,6-disila-1-azacyclohexane, cyclic trisilazane compounds like 2,2,4,4,6,6-hexamethylcyclotrisilazane and 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane, and cyclic tetrasilazane compounds like 2,2,4,4,6,6,8,8-octamethylcyclotetrasilazane.

[0074] When the silylating agent is supplied in the form of a gas, it may be supplied as a mixed gas containing an inert gas. ２ , Ar, He, Ne, CF ４ etc. Preferably, N ２ , Ar, or He may also be used.

[0075] The silylation composition refers to a composition containing two or more of the above-mentioned silylating agents in combination, or a composition containing the above-mentioned mixed gas and a compound other than the silylating agent. The silylation composition may contain, in addition to the silylating agent, a catalytic compound that promotes the silylation reaction caused by the silylating agent. The catalytic compound is preferably one or more selected from the group consisting of Compound A (described below), acid imides, nitrogen-containing compounds, silicon-free nitrogen-containing heterocyclic compounds, and silylated heterocyclic compounds. The catalytic compound here refers to a compound that can promote the reaction between the above-mentioned surfaces and the silylating agent or enhance the water-repellent properties of the resulting water-repellent film, and may itself or a modified compound thereof may constitute part of the water-repellent film.

[0076] The concentration of the catalytic compound may be, for example, 0.005% by mass or more and 20% by mass or less, or 0.05% by mass or more and 15% by mass or less, relative to 100% by mass of the silylation composition.

[0077] Specific examples of the compound A include, for example, trimethylsilyl trifluoroacetate, trimethylsilyl trifluoromethanesulfonate, dimethylsilyl trifluoroacetate, dimethylsilyl trifluoromethanesulfonate, butyldimethylsilyl trifluoroacetate, butyldimethylsilyl trifluoromethanesulfonate, hexyldimethylsilyl trifluoroacetate, hexyldimethylsilyl trifluoromethanesulfonate, octyldimethylsilyl trifluoroacetate, octyldimethylsilyl trifluoromethanesulfonate, decyldimethylsilyl trifluoroacetate, and decyldimethylsilyl trifluoromethanesulfonate, and can contain one or more selected from them.These may be used alone or in combination of two or more.In addition, the compound A may also correspond to the above-mentioned silylating agent, but when used as a catalytic compound, it means that the compound A used and the above-mentioned silylating agent are used in combination.

[0078] The compound A may be obtained by reacting a silicon compound represented by the following general formula [2] with one or more acetic acids or sulfonic acids selected from the group consisting of trifluoroacetic acid, trifluoroacetic anhydride, trifluoromethanesulfonic acid, and trifluoromethanesulfonic anhydride. Any excess silicon compound represented by the following general formula [2] that remains unconsumed in the reaction can be used as the silylating agent together with the compound A obtained by the reaction. The silicon compound represented by the following general formula [2] may be reacted, for example, in a molar ratio of 0.2 to 100,000 times, preferably 0.5 to 50,000 times, more preferably 1 to 10,000 times, the acetic acid or sulfonic acid.

[0079] R ２ ｃ (H) ｄ Si-X [2]

[0080] In the above general formula [2], R ２ ｃ (H) ｄ As Si-, (CH ３ ) ３ Si-, (CH ３ ) ２ (H)Si-, (C ４ H ９ ) (CH ３ ) ２ Si-, (C ６ H １３ ) (CH ３ ) ２ Si-, (C ８ H １７ ) (CH ３ ) ２ Si-, (C １０ H ２１ ) (CH ３ ) ２ Si-, etc. X is the same as in the general formula [1] above.

[0081] The compound A may be at least one selected from the group consisting of sulfonic acids represented by the following general formula [3], anhydrides of the sulfonic acids, salts of the sulfonic acids, and sulfonic acid derivatives represented by the following general formula [4]: ８ -S(=O) ２ OH [3] [In the above general formula [3], R ８ is a group selected from the group consisting of monovalent hydrocarbon groups having 1 to 8 carbon atoms, some or all of whose hydrogen atoms may be replaced by fluorine atoms, and hydroxyl groups.] R ８' -S(=O) ２ O—Si(H) ３－ｒ (R ９ ) ｒ [4] [In the above general formula [4], R ８' is a monovalent hydrocarbon group having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and R ９ are each independently at least one group selected from monovalent hydrocarbon groups having 1 to 18 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and r is an integer of 1 to 3.

[0082] Furthermore, the compound A may be at least one selected from the group consisting of sulfonate esters represented by the following general formula [5], sulfonimides represented by the following general formulas [6] and [7], sulfonimide derivatives represented by the following general formulas [8] and [9], sulfonmethides represented by the following general formula

[10] , and sulfonmethide derivatives represented by the following general formula

[11] . １０ -S(=O) ２ OR １１ [5] [In the above general formula [5], R １０ is a group selected from the group consisting of monovalent hydrocarbon groups having 1 to 8 carbon atoms, some or all of whose hydrogen atoms may be replaced by fluorine atoms, and fluorine atoms; R １１ is a monovalent alkyl group having 1 to 18 carbon atoms. １２ -S(=O) ２ ) ２ NH [6] [In the above general formula [6], R １２ are each independently a group selected from the group consisting of a monovalent hydrocarbon group having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and fluorine atoms. [In the above general formula [7], R １３ is a divalent hydrocarbon group having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms. １４ -S(=O) ２ ) ２ N) ｓ Si(H) ｔ (R １５ ) ４－ｓ－ｔ [8] [In the above general formula [8], R １４ are each independently a group selected from the group consisting of monovalent hydrocarbon groups having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and fluorine atoms; R １５ are each independently a monovalent hydrocarbon group having 1 to 18 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, s is an integer of 1 to 3, t is an integer of 0 to 2, and the sum of s and t is 3 or less. [In the above general formula [9], R １６are each independently a divalent hydrocarbon group having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and R １７ are each independently a monovalent hydrocarbon group having 1 to 18 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, u is an integer of 1 to 3, v is an integer of 0 to 2, and the sum of u and v is 3 or less.] (R １８ -S(=O) ２ ) ３ CH

[10] [In the above general formula

[10] , R １８ are each independently a group selected from the group consisting of a monovalent hydrocarbon group having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and fluorine atoms. １９ -S(=O) ２ ) ３ C) ｗ Si(H) ｘ (R ２０ ) ４－ｗ－ｘ

[11] [In the above general formula

[11] , R １９ are each independently a group selected from the group consisting of monovalent hydrocarbon groups having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and fluorine atoms; R ２０ are each independently a monovalent hydrocarbon group having 1 to 18 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, w is an integer of 1 to 3, x is an integer of 0 to 2, and the sum of w and x is 3 or less.

[0083] Furthermore, examples of the acid imides that can be used as catalytic compounds include compounds having a chemical structure in which an acid such as a carboxylic acid or phosphoric acid is imidized.

[0084] The nitrogen-containing compound that can be used as the catalytic compound includes at least one of the compounds represented by the following general formulas

[12] and

[13] : ２１ -N=C(NR ２２ ２ ) ２

[12] R ２１ -N=C(NR ２２２ ) R ２２

[13] [In the above general formulas

[12] and

[13] , R ２１ represents a hydrogen group, a —C≡N group, or —NO ２ R is selected from a hydrocarbon group in which some or all of the hydrogen atoms may be replaced by fluorine atoms, an alkylsilyl group, and the hydrocarbon group may contain oxygen atoms and / or nitrogen atoms, but when it contains a nitrogen atom, it is considered to have a non-cyclic structure. ２２ are each independently a hydrogen group, a —C≡N group, or —NO ２ and hydrocarbon groups in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and the hydrocarbon groups may contain oxygen atoms and / or nitrogen atoms, but when they contain nitrogen atoms, they are considered to have a non-cyclic structure.] Furthermore, examples of the nitrogen-containing compounds include compounds having a guanidine skeleton, such as guanidine, 1,1,3,3-tetramethylguanidine, 2-tert-butyl-1,1,3,3-tetramethylguanidine, 1,3-diphenylguanidine, 1,2,3-triphenylguanidine, N,N'-diphenylformamidine, and 2,2,3,3,3-pentafluoropropylamidine.

[0085] Furthermore, examples of the above-mentioned nitrogen-containing heterocyclic compounds not containing silicon atoms and silylated heterocyclic compounds that can be used as catalytic compounds include at least one of compounds represented by the following general formulas

[14] and

[15] : [In the above general formula

[14] , R ２３ and R ２４ are each independently a divalent organic group consisting of a carbon element and / or a nitrogen element and a hydrogen element, and the total number of carbon atoms and nitrogen atoms is 1 to 9, and when there are 2 or more carbon atoms, there may be carbon atoms that do not constitute the ring.] [In the above general formula

[15] , R ２５is an alkyl group having 1 to 6 carbon atoms in which some or all of the hydrogen atoms may be replaced by elemental fluorine, a trialkylsilyl group having an alkyl group having 1 to 8 carbon atoms in which some or all of the hydrogen atoms may be replaced by elemental fluorine, an alkenyl group having 2 to 6 carbon atoms in which some or all of the hydrogen atoms may be replaced by elemental fluorine, an alkoxy group having 1 to 6 carbon atoms in which some or all of the hydrogen atoms may be replaced by elemental fluorine, an amino group, an alkylamino group having an alkyl group having 1 to 6 carbon atoms in which some or all of the hydrogen atoms may be replaced by elemental fluorine, a dialkylamino group having an alkyl group having 1 to 6 carbon atoms in which some or all of the hydrogen atoms may be replaced by elemental fluorine, an aminoalkyl group having 1 to 6 carbon atoms in which some or all of the hydrogen atoms may be replaced by elemental fluorine, a nitro group, a cyano group, a phenyl group, a benzyl group, or a halogen group; R ２６ , R ２７ and R ２８ are each independently an alkyl group having 1 to 6 carbon atoms in which some or all of the hydrogen atoms may be replaced by fluorine atoms, or a hydrogen group.

[0086] The silicon-free nitrogen-containing heterocyclic compound may contain heteroatoms other than nitrogen atoms, such as oxygen atoms and sulfur atoms, in the ring, may have aromaticity, and may be a compound in which two or more rings are bonded by a single bond or a polyvalent linking group having a valence of two or more. It may also have a substituent. Examples of the silicon-free nitrogen-containing heterocyclic compound include pyridine, pyridazine, pyrazine, pyrimidine, triazine, tetrazine, pyrrole, pyrazole, imidazole, triazole, tetrazole, oxazole, isoxazole, thiazole, isothiazole, oxadiazole, thiadiazole, quinoline, isoquinoline, cinnoline, phthalazine, quinoxaline, quinazoline, indole, indazole, benzimidazole, benzotriazole, benzoxazole, benzisoxazole, benzothiazole, benzisothiazole, benzoxadiazole, benzothiadiazole, saccharin, pyrrolidine, and piperidine.

[0087] In addition, the above-mentioned silylated heterocyclic compounds include silylated imidazole compounds and silylated triazole compounds. Examples of silylated heterocyclic compounds include monomethylsilylimidazole, dimethylsilylimidazole, trimethylsilylimidazole, monomethylsilyltriazole, dimethylsilyltriazole, trimethylsilyltriazole, etc. It should be noted that some of the above-mentioned silylated heterocyclic compounds correspond to the above-mentioned silylating agents, but when used as a catalytic compound, this means that they are used in combination with other silylating agents other than the silylated heterocyclic compounds.

[0088] In the silylation composition, the concentration of the silylating agent, or the total concentration of the silylating agent and the catalytic compound, relative to 100% by mass of the silylation composition, may be, for example, 0.01% by mass to 100% by mass, preferably 0.1% by mass to 50% by mass, and more preferably 0.5% by mass to 30% by mass.

[0089] Additionally, when the silylation composition is a liquid, the silylation composition may include a solvent.

[0090] The solvent is not particularly limited as long as it dissolves the silylating agent. Examples of solvents that can be used include organic solvents such as hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide-based solvents, alcohols, carbonate-based solvents, polyhydric alcohol derivatives, nitrogen-containing solvents, silicone solvents, and thiols. Among these, hydrocarbons, esters, ethers, halogen-containing solvents, sulfoxide-based solvents, and polyhydric alcohol derivatives that do not have an OH group are preferred. These solvents may be used alone or in combination of two or more.

[0091] Examples of the hydrocarbons include linear, branched, or cyclic hydrocarbon solvents, aromatic hydrocarbon solvents, and terpene solvents, such as n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, n-tetradecane, n-hexadecane, n-octadecane, and n-eicosane, as well as branched hydrocarbons corresponding to the carbon numbers thereof (e.g., isododecane, isocetane, etc.), cyclohexane, methylcyclohexane, and the like. Examples of the solvent include cyclohexane, decalin, benzene, toluene, xylene, (ortho-, meta-, or para-)diethylbenzene, 1,3,5-trimethylbenzene, naphthalene, mesitylene, p-menthane, o-menthane, m-menthane, diphenylmenthane, limonene, α-terpinene, β-terpinene, γ-terpinene, bornane, norbornane, pinane, α-pinene, β-pinene, carane, longifolene, abietane, and terpene solvents.

[0092] Examples of the esters include ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-pentyl acetate, i-pentyl acetate, n-hexyl acetate, n-heptyl acetate, n-octyl acetate, n-pentyl formate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, i-propyl butyrate, n-butyl butyrate, methyl n-octanoate, methyl decanoate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl 2-oxobutanoate, dimethyl adipate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, and ethyl ethoxyacetate.

[0093] Furthermore, the esters may be cyclic esters such as lactone compounds. Examples of lactone compounds include β-propiolactone, γ-butyrolactone, γ-valerolactone, γ-hexanolactone, γ-heptanolactone, γ-octanolactone, γ-nonanolactone, γ-decanolactone, γ-undecanolactone, γ-dodecanolactone, δ-valerolactone, δ-hexanolactone, δ-octanolactone, δ-nonanolactone, δ-decanolactone, δ-undecanolactone, δ-dodecanolactone, and ε-hexanolactone.

[0094] Examples of the ethers include di-n-propyl ether, ethyl-n-butyl ether, di-n-butyl ether, ethyl-n-amyl ether, di-n-amyl ether, ethyl-n-hexyl ether, di-n-hexyl ether, di-n-octyl ether, as well as ethers having a branched hydrocarbon group such as diisopropyl ether and diisoamyl ether corresponding to the carbon numbers of these ethers, dimethyl ether, diethyl ether, methyl ethyl ether, methylcyclopentyl ether, diphenyl ether, tetrahydrofuran, and dioxane.

[0095] Examples of the ketones include acetone, acetylacetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, cyclohexanone, and isophorone.

[0096] Examples of the halogen element-containing solvent include perfluorocarbons such as perfluorooctane, perfluorononane, perfluorocyclopentane, perfluorocyclohexane, and hexafluorobenzene; hydrofluorocarbons such as 1,1,1,3,3-pentafluorobutane, octafluorocyclopentane, 2,3-dihydrodecafluoropentane, and Zeorora H (manufactured by Zeon Corporation); methyl perfluoropropyl ether, methyl perfluoroisobutyl ether, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, ethyl perfluoroisobutyl ether, methyl perfluorohexyl ether, ethyl perfluorohexyl ether, Asahiklin AE-3000 (manufactured by Asahi Glass Co., Ltd.), Novec HFE-7100, and Novec Examples of such hydrocarbons include hydrofluoroethers such as HFE-7200, Novec7300, and Novec7600 (all manufactured by 3M), chlorocarbons such as tetrachloromethane, hydrochlorocarbons such as chloroform, chlorofluorocarbons such as dichlorodifluoromethane, hydrochlorofluorocarbons 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, and 1,2-dichloro-3,3,3-trifluoropropene, perfluoroethers, and perfluoropolyethers.

[0097] Examples of the sulfoxide solvent include dimethyl sulfoxide.

[0098] Examples of the carbonate solvent include dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, and propylene carbonate.

[0099] Examples of the alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, 4-methyl-1-pentanol, 2- Examples include methyl-2-pentanol, 3-methyl-2-pentanol, 4-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-3-pentanol, 2,2-dimethyl-1-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 4-heptanol, benzyl alcohol, 1-octanol, isooctanol, 2-ethyl-1-hexanol, and 4-methyl-2-pentanol.

[0100] Examples of the derivatives of the above polyhydric alcohols that do not have an OH group include ethylene 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, and triethylene glycol monoethyl ether acetate. acetate, 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 methylpropyl 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, butylene glycol dimethyl ether, butylene glycol monomethyl ether acetate, butylene glycol diacetate, glycerin triacetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, etc.

[0101] Examples of the nitrogen-containing solvent include formamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, 1,3-diisopropyl-2-imidazolidinone, diethylamine, triethylamine, and pyridine.

[0102] Examples of the silicone solvent include hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, and dodecamethylpentasiloxane.

[0103] Examples of the thiols include 1-hexanethiol, 2-methyl-1-pentanethiol, 3-methyl-1-pentanethiol, 4-methyl-1-pentanethiol, 2,2-dimethyl-1-butanethiol, 3,3-dimethyl-1-butanethiol, 2-ethyl-1-butanethiol, 1-heptanethiol, benzylthiol, 1-octanethiol, 2-ethyl-1-hexanethiol, 1-nonanethiol, 1-decanethiol, 1-undecanethiol, 1-dodecanethiol, and 1-tridecanethiol.

[0104] The solvent preferably contains an aprotic solvent. The content of the aprotic solvent is, for example, 80% by mass or more, preferably 90% by mass or more, relative to 100% by mass of the solvent. It is more preferable that the solvent is an aprotic solvent, i.e., the solvent contains the aprotic solvent at a content of 100% by mass relative to 100% by mass of the solvent.

[0105] Aprotic solvents include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxides, carbonate solvents, polyhydric alcohol derivatives, nitrogen-containing solvents, silicone solvents, etc. These may be used alone or in combination of two or more. Among these, it is preferable to use one or more selected from the group consisting of polyhydric alcohol derivatives, hydrocarbons, and ethers.

[0106] From the viewpoint of cost and solubility, derivatives of polyhydric alcohols (which do not have an OH group in the molecule) are preferred, such as diethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol diacetate, triethylene glycol dimethyl ether, ethylene glycol diacetate, ethylene glycol dimethyl ether, 3-methoxy-3-methyl-1-butyl acetate, Preferred are propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether, 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, and dipropylene glycol diacetate. Also preferred are propylene carbonate, linear or branched hydrocarbon solvents having 6 to 12 carbon atoms, p-menthane, diphenylmenthane, limonene, terpinene, bornane, norbornane, and pinane.

[0107] Examples of silylation compositions containing a silylating agent and a solvent include those in which the silylating agent is hexamethyldisilazane, heptamethyldisilazane, N-(trimethylsilyl)dimethylamine, bis(dimethylamino)dimethylsilane, bis(trimethylsilyl)trifluoroacetamide, N-methyl-N-trimethylsilyltrifluoroacetamide, N-trimethylsilylacetamide, N-trimethylsilylimidazole, trimethylsilyltriazole, bistrimethylsilyl sulfate, 2,2,5,5-tetramethyl-2,5-disila-1-azacyclopentane, 2,2,4,4,6,6-hexamethyldisilaz ... The catalyst may contain one or more selected from the group consisting of trimethylsilylcyclotrisilazane, hexamethyldisiloxane, trimethylsilyl trifluoroacetate, trimethylsilyl trifluoromethanesulfonate, trimethylsilylbenzenesulfonate, and trimethylsilyl toluenesulfonate, and the solvent may contain one or more selected from the group consisting of propylene carbonate, linear hydrocarbon solvents having 7 to 10 carbon atoms, menthane, pinane, γ-butyrolactone, propylene glycol monomethyl ether acetate, and 3-methoxy-3-methyl-1-butyl acetate.

[0108] The silylation composition may contain no water or may contain water in an amount of 2% by mass or less based on 100% by mass of the silylation composition, making it possible to use a silylation composition that is substantially free of water.

[0109] The silylation composition may contain other components in addition to those described above, provided that the purpose of the present invention is not impaired. Examples of such other components include oxidizing agents such as hydrogen peroxide and ozone, surfactants, and antioxidants such as BHT.

[0110] The silylation composition of this embodiment is obtained by mixing the above-mentioned components. The obtained mixture may be purified using an adsorbent, a filter, or the like, as necessary. Alternatively, each component may be purified in advance by distillation, or may be purified using an adsorbent, a filter, or the like.

[0111] Although the embodiments of the present invention have been described above, these are merely illustrative of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc., within the scope of achieving the object of the present invention are included in the present invention. Examples of reference embodiments are listed below. 1. A method for treating a substrate, comprising: a preparation step of preparing a substrate having at least an exposed first surface containing silicon oxide and a second surface containing silicon nitride; a surface modification step of forming an etching selectivity-imparting film on at least a portion of the first surface and at least a portion of the second surface by a silylation treatment in which a silylating agent is brought into contact with the first surface and the second surface; and an etching step of selectively etching the second surface relative to the first surface using an etching agent after the surface modification step. 2. A method for treating a substrate according to 1., wherein, in the surface modification step, a first water contact angle of the etching selectivity-imparting film on the first surface is greater than a second water contact angle of the etching selectivity-imparting film on the second surface. 3.2. 3. The method for treating a substrate according to any one of 1. to 3., wherein a difference between the first water contact angle and the second water contact angle is 5° or more. 4. The method for treating a substrate according to any one of 1. to 3., comprising a cleaning step of cleaning with a cleaning agent between the surface modification step and the etching step. 5. The method for treating a substrate according to 4., wherein the liquid temperature of the cleaning agent is 60°C or less. 6. The method for treating a substrate according to 4. or 5., wherein the cleaning agent comprises an aqueous cleaning solution and / or a rinse solution. 7. The method for treating a substrate according to any one of 4. to 6., wherein a cycle comprising at least the surface modification step, the cleaning step, and the etching step, in this order, is carried out two or more times.8. A method for treating a substrate according to any one of 1. to 7., wherein the surface modification step involves performing a pretreatment before the silylation treatment, and the pretreatment includes a treatment for increasing the difference between a first water contact angle in the etching selectivity imparting film on the first surface and a second water contact angle in the etching selectivity imparting film on the second surface. 9. A method for treating a substrate according to any one of 1. to 8., wherein after the etching step, a removal treatment is performed for removing at least a portion of the etching selectivity imparting film on the first surface. 10. A method for treating a substrate according to any one of 1. to 9., wherein a cycle including at least the surface modification step and the etching step, in this order, is performed two or more times. 11. A method for treating a substrate according to any one of 1. to 10., wherein in the silylation treatment, the etching selectivity imparting film is formed using a silylation composition including the silylating agent and a catalytic compound. 12. 13. A method for treating a substrate according to any one of 1. to 11., wherein the silylation treatment uses the silylating agent or a silylation composition containing the silylating agent and at least one of a solvent, a diluent gas, and a catalytic compound. 13. A method for producing a substrate, comprising each step of the method for treating a substrate according to any one of 1. to 12.

[0112] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions of these examples.

[0113] Examples 1 to 6 Etching treatment was performed on a substrate using the method described below in "Substrate Treatment." The treatment conditions for each example are shown in Table 1. Substrate Treatment (1. Substrate Preparation Step) A silicon substrate with a smooth surface measuring 30 mm x 40 mm x 1 mm was used as the substrate. A silicon oxide film or a silicon nitride film was formed on the surface of this substrate, and the substrate with the silicon oxide film formed thereon was regarded as the first surface, and the substrate with the silicon nitride film formed thereon was regarded as the second surface. In Table 1, the silicon oxide film is represented as SiO and the silicon nitride film is represented as SiN (however, the composition ratio is not necessarily limited to Si:O=1:1 or Si:N=1:1). The following is a simulation test using the above substrate.

[0114] (2. Surface Modification Step) The prepared substrate was subjected to a surface modification treatment in the following order under the following treatment conditions: pretreatment A and silylation treatment B. The treatment conditions for each treatment used in the surface modification step are as follows: (2.1) Pretreatment A (A-1) Removal of Native Oxide Film At room temperature, the substrate was immersed in a 0.02 to 1 mass % aqueous hydrofluoric acid solution (DHF) for 1 minute, and then immersed in pure water as a rinse solution, followed by 2-propanol (IPA) for 1 minute each. (2.2) Silylation Treatment B The substrate was immersed in silylation agent B-1 prepared by the following method at room temperature for 0.3 minutes, 1 minute, 5 minutes, or 10 minutes to perform a silylation treatment on the surface of the substrate. The substrate was then immersed in IPA for 1 minute. The substrate was then removed and dried by spraying nitrogen gas to remove the IPA (cleaning treatment). (Silylating Agent B-1) Silylating agent B-1 was obtained by weighing out and mixing 5 g of hexamethyldisilazane (HMDS), 0.1 g of trimethylsilyl trifluoroacetate, and 94.9 g of propylene glycol monomethyl ether acetate (PGMEA) at room temperature. (Silylating Agent B-2) Silylating agent B-2 was obtained by weighing out and mixing 12 g of 1,3-dioctyl-1,1,3,3-tetramethyldisilazane, 0.5 g of octyldimethylsilyl trifluoroacetate, and 87.5 g of PGMEA at room temperature. (Silylating Agent B-3) Silylating agent B-3 was obtained by weighing out and mixing 12 g of HMDS, 4 g of trimethylsilyl trifluoroacetate, and 84 g of PGMEA at room temperature.

[0115] (3. Etching Step) After the above (2. Surface Modification Step), the substrate was immersed in a 0.5% by mass aqueous solution of hydrogen fluoride for 1 minute, 3 minutes, and 5 minutes at room temperature (25°C) (etching treatment). After the etching treatment, the substrate was immersed in pure water for 1 minute. Thereafter, the substrate was taken out and dried by spraying nitrogen gas to remove water (cleaning treatment).

[0116] Comparative Example Etching and cleaning were carried out in the same manner as in Example 1, except that the silylation treatment B was not carried out and the etching treatment time was changed to 1 minute and 3 minutes.

[0117] The substrates were evaluated for the following items during or after the treatment described above in <Substrate Treatment>.

[0118]

[0119] <Measurement and Evaluation of Water Contact Angle> (Measurement of Water Contact Angle) The water contact angle (°) on the surface of the substrate immediately before etching was measured according to the following measurement procedure. First, the substrate was immersed in IPA at 25°C for 1 minute. Next, air was blown onto the substrate to dry it. Next, the substrate was placed horizontally with the surface subjected to treatment A facing up, and a 2 μl droplet of pure water was placed on the surface. Next, the angle between the water droplet and the substrate (water contact angle) was measured using a contact angle meter (CA-X model, manufactured by Kyowa Interface Science Co., Ltd.) in accordance with JIS R 3257:1999 "Test method for wettability of substrate glass surfaces." The temperature during measurement was room temperature (approximately 25°C).

[0120] (Measurement of Water Receding Angle) The water receding angle (°) on the surface of the substrate immediately before etching was measured according to the following procedure. First, 30 μl of pure water was dropped onto the surface of the surface-treated substrate while it was placed stationary on a horizontal table at room temperature of 25°C. Next, the pure water was aspirated at a rate of 6 μl / sec, and the water contact angle was measured while the droplet size was decreasing, and this value was taken as the water receding angle (°). Note that the water contact angle shows the normal water contact angle (static contact angle) value at the beginning of suction, but begins to change as suction begins, and as suction continues, the amount of change in the water contact angle decreases and becomes approximately constant. The water contact angle when the amount of change becomes small was used as the water receding angle.

[0121] <Etching Amount, Etching Selectivity> The film thickness of the silicon oxide film and silicon nitride film formed on the substrate was measured using an ellipsometer (SE-2000, manufactured by Nippon Semilab Co., Ltd.). Film thickness measurements were performed on samples subjected to silylation treatment B for 0.3 minutes, 1 minute, 5 minutes, and 10 minutes, as well as on a sample without silylation treatment, before the etching treatment (0 minute) and after each etching treatment using the aforementioned immersion time. The difference in film thickness reduction from the initial film thickness (before the etching treatment) was calculated as the etching amount (nm). The results are shown in Table 1.

[0122] [Example 7] <Substrate Treatment> (1. Substrate Preparation Step) The substrates used were a silicon substrate having a smooth surface and a size of 30 mm × 40 mm × 1 mm, and a substrate on which a silicon oxide film was formed in the same manner as in Example 1. The substrate on which the silicon oxide film was formed was regarded as the first surface, and the silicon substrate on which the silicon oxide film was not formed was regarded as the second surface.

[0123] (2. Surface Modification Step) The prepared substrate was subjected to a surface modification treatment in the following order under the following treatment conditions: pretreatment A and silylation treatment B. The treatment conditions for each treatment used in the surface modification step are as follows. (2.1) Pretreatment A (A-1) Removal of Native Oxide Film At room temperature, the substrate was immersed in a 1% by mass aqueous solution of hydrofluoric acid (DHF) for 1 minute, and then immersed in pure water as a rinse solution and then 2-propanol (IPA) for 1 minute each. (2.2) Silylation Treatment B The substrate was immersed in the silylating agent B-3 prepared by the method described above for 3 minutes at room temperature, and the surface of the substrate was subjected to a silylation treatment. The substrate was then immersed in IPA for 1 minute. The substrate was then removed and dried by spraying nitrogen gas to remove the IPA (cleaning treatment).

[0124] (3. Etching Step) First, the substrate after the (2. Surface Modification Step) was etched with the following oxidizing agent (NH ３ 0.5 wt%, H ２ O ２ An aqueous solution containing 1.0 wt% of ３ : H ２ O ２The substrate was immersed in a 0.1% by mass aqueous solution of hydrogen fluoride (SiO 2 : SiO 2 : SiO 2 = 1:2:50) for 1 minute. The substrate was then immersed in pure water for 1 minute (oxidation treatment). The oxidized substrate was then immersed in a 0.1% by mass aqueous solution of hydrogen fluoride for 1 minute at room temperature (25°C) (etching treatment). After the etching treatment, the substrate was immersed in pure water for 1 minute. The substrate was then removed and dried by spraying nitrogen gas onto it to remove the water (cleaning treatment).

[0125] Using the substrates during or after the treatment described above in <Substrate Treatment>, the items listed in Table 2 were evaluated. The measurement methods were the same as in Examples 1 to 6. The results are shown in Table 2.

[0126]

[0127] <Evaluation of heated cleaning treatment> The water contact angle (°) of a silicon nitride film (second surface) and a silicon oxide film (first surface) formed on a substrate immediately before etching was measured using the method described above, with and without silylation treatment, before and after the cleaning treatment (immersion) under the conditions shown in Table 3. As a result, by performing silylation treatment on not only the silicon oxide film (first surface) but also the silicon nitride film (second surface), the water contact angle was relatively maintained even when the temperature of the cleaning agent (DIW) was 40 to 60°C, compared to the case without silylation treatment, and it can be expected that the effects of etching selectivity and liquid drainage will also be maintained.

[0128]

[0129] The above results demonstrate that the substrate treatment methods of the examples improve the liquid drainage immediately after the silylation treatment and the etching selectivity during the etching treatment in substrates having a first surface containing silicon oxide and a second surface containing silicon nitride, compared to the comparative example in which the silylation treatment was not performed. Furthermore, it was also demonstrated that the liquid drainage immediately after the silylation treatment was improved in substrates having a first surface containing silicon oxide and a second surface containing silicon, and that by performing an oxidation treatment before the etching treatment, the etching selectivity during the etching treatment in substrates having a first surface containing silicon oxide and a second surface containing silicon could be improved.

[0130] This application claims priority based on Japanese Patent Application No. 2022-090144, filed on June 2, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0131] REFERENCE SIGNS LIST 1 substrate 1a substrate surface 11 first surface 12 second surface 20 silylation agent, silylation composition 21 water-repellent film 22 water-repellent film

Claims

1. a preparation step of preparing a substrate having at least an exposed first surface containing silicon oxide and an exposed second surface containing silicon or a silicon compound other than silicon oxide; a surface modification step of forming an etching selectivity-imparting film on at least a portion of the first surface and at least a portion of the second surface by a silylation treatment in which a silylating agent is brought into contact with the first surface and the second surface; an etching step of selectively etching the second surface with respect to the first surface using an etching agent after the surface modification step; Methods for treating substrates.

2. 2. The method for treating a substrate according to claim 1, The surface modification step involves performing a pretreatment before the silylation treatment, The method for treating a substrate, wherein the pretreatment includes a treatment for increasing a difference between a first water contact angle of the etching selectivity imparting film on the first surface and a second water contact angle of the etching selectivity imparting film on the second surface.

3. 3. A method for treating a substrate according to claim 1 or 2, comprising: In the preparing step, the base material contains a silicon compound having an N element on the second surface, a substrate treatment method in which, after the surface modification step, the etching step is carried out without subjecting the second surface to an oxidation treatment in which an oxidizing agent is brought into contact with the second surface;

4. 3. A method for treating a substrate according to claim 1 or 2, comprising: In the preparing step, the base material contains, on the second surface, a silicon compound having at least one element selected from the group consisting of an N element, a C element, and a metal element, or silicon; A method for treating a substrate, wherein, after the surface modification step, the etching step comprises carrying out an oxidation treatment in which an oxidizing agent is brought into contact with the second surface, and then carrying out the etching treatment.

5. 3. A method for treating a substrate according to claim 1 or 2, comprising: A method for treating a substrate, wherein in the surface modification step, a first water contact angle of the etching selectivity imparting film on the first surface is greater than a second water contact angle of the etching selectivity imparting film on the second surface.

6. 6. The method for treating a substrate according to claim 5, A method for treating a substrate, wherein a difference between the first water contact angle and the second water contact angle is 5° or more.

7. 3. A method for treating a substrate according to claim 1 or 2, comprising: The method for treating a substrate further comprises, between the surface modification step and the etching step, a cleaning step of cleaning the first surface and the second surface using a cleaning agent.

8. 8. The method for treating a substrate according to claim 7, The method for treating a substrate, wherein the liquid temperature of the cleaning agent is 60°C or less.

9. 8. The method for treating a substrate according to claim 7, A method of treating a substrate, wherein the cleaning agent comprises an aqueous cleaning solution and / or a rinse solution.

10. 8. The method for treating a substrate according to claim 7, A method for treating a substrate, comprising carrying out a cycle including at least the surface modification step, the cleaning step, and the etching step in this order, two or more times.

11. 3. A method for treating a substrate according to claim 1 or 2, comprising: A method for treating a substrate, comprising, after the etching step, a removal treatment for removing at least a portion of the etching selectivity imparting film on the first surface.

12. 3. A method for treating a substrate according to claim 1 or 2, comprising: A method for treating a substrate, comprising carrying out a cycle including at least the surface modification step and the etching step in this order two or more times.

13. 3. A method for treating a substrate according to claim 1 or 2, comprising: The method for treating a substrate, wherein the etching selectivity-imparting film is formed in the silylation treatment using a silylation composition containing the silylating agent and a catalytic compound.

14. A method for manufacturing a substrate, comprising the steps of the method for treating a substrate according to claim 1 or 2.