Protective film forming agent for silicon-based substrates, method for processing silicon-based substrates, and method for manufacturing semiconductor devices

Abstract

The present invention provides a protective film-forming agent for silicon-based substrates that can form a protective film on a silicon-based substrate without damaging the resist, a method for processing a silicon-based substrate, and a method for manufacturing a semiconductor device. [Solution] The present invention provides a protective film-forming agent for silicon-based substrates, a method for processing silicon-based substrates, and a method for manufacturing semiconductor devices, comprising a silylation agent and a solvent having a Hildebrand SP value of 17.5 or less.

Description

[Technical Field]

[0001] The present invention relates to a protective film-forming agent for silicon-based substrates, a method for processing silicon-based substrates, and a method for manufacturing semiconductor devices. [Background technology]

[0002] In the manufacturing process of semiconductor devices, for example, a laminated substrate in which a silicon oxide film (SiO2) or silicon nitride film (SiN) is formed on a substrate such as a silicon-based substrate is etched. During this process, an etching protective film using a silylation agent is used to control the amount of etching and to selectively etch the substrate. Furthermore, if an etching protective film can be formed on exposed areas of the silicon-based substrate in the presence of a resist, the degree of freedom in pattern formation for semiconductor devices can be improved.

[0003] Regarding such technologies, Patent Document 1 discloses a substrate processing method that includes a moisture removal step of removing moisture adsorbed on the silicon oxide film from a substrate having a surface in which a silicon nitride film and a silicon oxide film are exposed, a silylation step of supplying a silylation agent to the substrate after the moisture removal step, and an etching step of supplying an etching agent to the substrate after the silylation step. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-105519 [Overview of the project] [Problems that the invention aims to solve]

[0005] The silylation agent forming agent described above is usually supplied to the substrate by a vapor method (a method in which the silylation agent is vaporized and brought into contact with the substrate). Patent Document 1 also discloses a method for forming an etching protective film by introducing a silylation agent vapor into a chamber. In this regard, the inventor diligently researched the matter and found that the conventional vapor method of supplying silylation agents has the problem of low reactivity with silicon-based substrates and low etching protection ability in that case. Furthermore, as a result of the inventor's detailed research, it was found that in the above-mentioned conventional technology using a silylation agent as a protective film forming agent for silicon-based substrates, it has not been possible to realize a forming agent that is excellent in not damaging the resist and in forming a protective film, and that there is room for improvement.

[0006] This invention has been made in view of these circumstances, and aims to provide a protective film-forming agent for silicon-based substrates that can form a protective film on a silicon-based substrate without damaging the resist, a method for processing a silicon-based substrate, and a method for manufacturing a semiconductor device. [Means for solving the problem]

[0007] As a result of diligent research to achieve the above-mentioned objectives, the inventors have found that a protective film-forming agent for silicon-based substrates comprises a silylation agent and a solvent having a Hildebrand SP value of 17.5 or less, and have completed the present invention.

[0008] In other words, the present invention is as follows. <1> This is a protective film-forming agent for silicon-based substrates, comprising a silylation agent and a solvent having a Hildebrand SP value of 17.5 or less. <2> The silylating agent is at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyldimethylamine, and bisdimethylaminodimethylsilane. <1> This is a protective film-forming agent for silicon-based substrates as described above. <3> The protective film forming agent for a silicon-based substrate according to any one of <1> to <2>, wherein the solvent is at least one selected from the group consisting of a hydrocarbon-based solvent, an ester-based solvent having one ester bond in the molecule, and an ether-based solvent having one ether bond in the molecule. <4> The protective film forming agent for a silicon-based substrate according to any one of <1> to <3>, wherein the content of the silylating agent is 1% by mass or more and 20% by mass or less. <5> The protective film forming agent for a silicon-based substrate according to any one of <1> to <4>, wherein the total content of the hydrocarbon-based solvent, the ester-based solvent having one ester bond in the molecule, and the ether-based solvent having one ether bond in the molecule in the total amount of the solvent is 80% by mass or more and 100% by mass or less. <6> The protective film forming agent for a silicon-based substrate according to any one of <1> to <5>, wherein the total content of the silylating agent and the solvent in the protective film forming agent for a silicon-based substrate is 80% by mass or more and 100% by mass or less. <7> The protective film forming agent for a silicon-based substrate according to any one of <1> to <6>, wherein a protective film can be formed on a silicon-based substrate including an organic film at least partially exposed. <8> (1) A step of subjecting the surface of a silicon-based substrate including an organic film at least partially exposed to an oxidation treatment; and (2) a step of forming a protective film by bringing a protective film forming agent for a silicon-based substrate into contact with at least a part of the surface of the silicon-based substrate that has been subjected to the oxidation treatment, wherein the protective film forming agent for a silicon-based substrate includes a silylating agent and a solvent having a Hildebrand's SP value of 17.5 or less, which is a method for treating a silicon-based substrate. <9> The method for treating a silicon-based substrate according to <8>, wherein the step (2) is a step of forming the protective film by immersing the protective film forming agent for a silicon-based substrate in at least a part of the surface of the silicon-based substrate that has been subjected to the oxidation treatment. <10> The silicon-based substrate is one or more selected from the group consisting of silicon oxide, carbon-containing silicon oxide, silicon nitride, silicon carbide, silicon carbonitride, silicon oxynitride, silicon oxycarbonitride, and silicon, and is the method for treating a silicon-based substrate according to <8> or <9>. <11> (1) A step of subjecting the surface of a silicon-based substrate including an organic film with at least a part thereof exposed to an oxidation treatment; and (2) a step of forming a protective film by bringing a protective film forming agent for a silicon-based substrate into contact with at least a part of the surface of the silicon-based substrate that has been subjected to the oxidation treatment, wherein the protective film forming agent for a silicon-based substrate includes a silylating agent and a solvent having a Hildebrand SP value of 17.5 or less, and is a method for manufacturing a semiconductor device. <12> The step (2) is a step of forming the protective film by immersing the protective film forming agent for a silicon-based substrate in at least a part of the surface of the silicon-based substrate that has been subjected to the oxidation treatment, and is the method for manufacturing a semiconductor device according to <11>. <13> After the step (2), The method for manufacturing a semiconductor device according to <11> or <12> further includes a step of etching the silicon-based substrate on which the protective film is formed. <14> The silicon-based substrate is one or more selected from the group consisting of silicon oxide, carbon-containing silicon oxide, silicon nitride, silicon carbide, silicon carbonitride, silicon oxynitride, silicon oxycarbonitride, and silicon, and is the method for manufacturing a semiconductor device according to any one of <11> to <13>.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a protective film forming agent for a silicon-based substrate, a method for treating a silicon-based substrate, and a method for manufacturing a semiconductor device that can form a protective film on a silicon-based substrate without damaging a resist.

Embodiments for Carrying Out the Invention

[0010] The following describes in detail embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment"). This embodiment is illustrative for explaining the present invention and is not intended to limit the present invention to the following content. The present invention can be implemented by modifying it as appropriate within the scope of its gist.

[0011] <Protective film forming agent for silicon-based substrates>

[0012] The protective film-forming agent for silicon-based substrates according to this embodiment comprises a silylation agent and a solvent having a Hildebrand SP value (hereinafter sometimes simply abbreviated as "SP value") of 17.5 or less. By using a solvent with a Hildebrand SP value of 17.5 or less as the solvent used in combination with the silylation agent, a protective film can be formed on the silicon-based substrate without damaging the resist. In other words, the protective film-forming agent for silicon-based substrates according to this embodiment can form a protective film without dissolving the resist. Thus, the protective film-forming agent for silicon-based substrates according to this embodiment has excellent resist dissolution suppression (resist dissolution suppression) and etching protection ability. The protective film-forming agent for silicon-based substrates according to this embodiment is preferably used in a wet manner, as this resist dissolution suppression and etching protection ability can be further improved by using it in a wet manner.

[0013] The reason why the protective film-forming agent for silicon-based substrates according to this embodiment can form a protective film without dissolving the resist is not entirely clear, but it is presumed to be for the following reasons. First, because a solvent with an SP value of 17.5 or less is used, unintended dissolution of the resist during processing can be suppressed. Second, because the SP value is 17.5 or less, the interaction between the solvent and the silylation agent can be suppressed, and the reaction between the silylation agent and the silicon-based substrate can be promoted. For these reasons, it is presumed that the above-mentioned effects can be obtained (however, the operation and effects of this embodiment are not limited to these).

[0014] (Silicon-based substrate)

[0015] The silicon-based substrate on which the protective film-forming agent for silicon-based substrates according to this embodiment is used is not particularly limited, but it is preferable that it be one or more selected from the group consisting of silicon oxide, carbon-containing silicon oxide, silicon nitride, silicon carbide, silicon carbonitride, silicon oxynitride, silicon oxycarbonitride, and silicon. With a silicon-based substrate made of such a material, the protective film-forming agent for silicon-based substrates according to this embodiment can more effectively form a protective film without dissolving the resist. Furthermore, the protective film can be formed on the exposed portion of the silicon-based substrate where the patterned resist according to this embodiment is present on the surface and at least a portion of it is exposed. In particular, by using a wet method, the protective film can be formed even more effectively without dissolving the resist.

[0016] (Silylaters)

[0017] The silylation agent is not particularly limited, but is preferably a compound containing a silazane skeleton or a compound containing a siloxane skeleton. More preferably, the silylation agent is at least one selected from the group consisting of hexamethyldisilazane (HMDS), trimethylsilyldimethylamine (TMSDMA), and bisdimethylaminodimethylsilane (BDMADMS). By using such a compound, the inhibitory effect on resist dissolution and the etching protection ability can be further improved.

[0018] The content of the silylation agent in the protective film-forming agent for silicon-based substrates according to this embodiment is not particularly limited, but is preferably 1% by mass or more and 20% by mass or less. The lower limit of this content is more preferably 3% by mass or more, and even more preferably 5% by mass or more. The upper limit of this content is more preferably 17% by mass or less, and even more preferably 15% by mass or less. By having the silylation agent content within this range, the inhibitory effect on resist dissolution and the etching protection ability can be further improved.

[0019] (solvent)

[0020] The solvent has an SP value of 17.5 or less. The SP value is the Hildebrand SP value, which is a solubility parameter defined as the square root of the cohesive energy density and is an index related to the dissolution behavior of the solvent. The Hildebrand SP value can be determined by the following formula (1). SP value = (δ d 2 + δ p 2 + δ h 2 ) 1 / 2 ···(1) (In the formula, δ d represents the dispersion force term, δ p represents the polar term, and δ h represents the hydrogen bond term.)

[0021] As an example, Table 1 shows the SP values of some solvents (Note that the solvents used in this embodiment are not limited to the following.).

[0022]

Table 1

[0023] In the protective film forming agent for a silicon-based substrate according to this embodiment, when two or more solvents are used in combination, the SP value of the mixed solvent may be 17.5 or less. The SP value of the mixed solvent can be obtained by summing the root mean square value of the total assigned volume ratio of each solvent for each of the dispersion force term δ d , the polar term δ p , and the hydrogen bond term δ h of the SP values of each solvent. For example, for solvent A with the dispersion force term, polar term, and hydrogen bond term being δ dA , δ pA , and δ hA respectively, for solvent B with δ dB , δ pB , and δ hB respectively, and for solvent C with δ dC , δpC , and δ hC In the case of a mixed solvent containing solvent C in proportions of 30% by volume, 20% by volume, and 50% by volume, the SP value of the mixed solvent can be determined by the following formula (2). SP value in mixed solvent = ((0.3 × δ dA +0.2×δ dB +0.5×δ dC ) 2 +(0.3×δ pA +0.2×δ pB +0.5×δ pC ) 2 +(0.3×δ hA +0.2×δ hB +0.5×δ hC ) 2 ) 1 / 2 ...(2)

[0024] The SP value should be 17.5 or less, but its lower limit is more preferably 10 or more, even more preferably 13 or more, even more preferably 15 or more, and even more preferably 15.5 or more. The upper limit of the SP value is preferably 17.3 or less, and even more preferably 17.1 or less. In the case of a mixed solvent containing two or more solvents, it is preferable that the SP value of the mixed solvent is within the above range.

[0025] In the case of a mixed solvent, for example, if the SP value of at least one of the mixed solvents is within the above-mentioned range (e.g., 17.5 or less), and the SP values ​​of the other solvents are outside the above-mentioned range (e.g., greater than 17), then it is sufficient if the SP values ​​of these mixed solvents are 17.5 or less. However, it is preferable that the mixed solvent contains only solvents with an SP value of 17.5 or less.

[0026] The type of solvent is not particularly limited, but it is preferably at least one selected from the group consisting of hydrocarbon solvents, ester solvents, and ether solvents; more preferably at least one selected from the group consisting of hydrocarbon solvents, ester solvents having one ester bond in the molecule, and ether solvents having one ether bond in the molecule.

[0027] Specific examples of hydrocarbon solvents used in the protective film-forming agent for silicon substrates according to this embodiment include hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, and hexadecane. Among these, decane, undecane, dodecane, and tridecane are more preferred.

[0028] Specific examples of ester-based solvents used in the protective film-forming agent for silicon-based substrates according to this embodiment include ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, hexyl acetate, dimethyl adipate, and diethyl adipate. Among these, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, and hexyl acetate are more preferred.

[0029] Specific examples of ether-based solvents used in the protective film-forming agent for silicon-based substrates according to this embodiment include diisopropyl ether, dibutyl ether, amyl ether, dimethoxyethane, and diethoxyethane. Among these, dibutyl ether is more preferred.

[0030] Furthermore, the protective film-forming agent for silicon-based substrates according to this embodiment can achieve the desired effect even without containing a thinner-based solvent. Also, the protective film-forming agent for silicon-based substrates according to this embodiment can achieve the desired effect even without containing propylene glycol monomethyl ether acetate (PGMEA). Moreover, the protective film-forming agent for silicon-based substrates according to this embodiment can achieve the desired effect even without containing propylene glycol methyl ether.

[0031] The solvent content in the protective film-forming agent for silicon-based substrates according to this embodiment is not particularly limited, but is preferably 60% to 99.5% by mass. The lower limit of this content is more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 85% by mass or more. The upper limit of this content may be 99.3% by mass or less, 90% by mass or less, or 85% by mass or less. By having the solvent content within this range, the inhibitory effect on resist dissolution and the etching protection ability can be further improved.

[0032] The total amount of hydrocarbon solvents, ester solvents having one ester bond in their molecule, and ether solvents having one ether bond in their molecule, in the total amount of solvent, is not particularly limited, but is preferably 80% by mass or more and 100% by mass or less. The lower limit is more preferably 85% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 98% by mass or more. Furthermore, it is even more preferable that the protective film-forming agent for substrates according to this embodiment contains only the solvents described above as the solvent. By using such a ratio, the inhibitory effect on resist dissolution and the etching protection ability can be further improved.

[0033] In the protective film-forming agent for silicon substrates according to this embodiment, the total content of the silylation agent and the solvent is not particularly limited, but is preferably 80% by mass or more and 100% by mass or less. The lower limit is more preferably 85% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 98% by mass or more. In addition, the content of components other than the solvent, other than the silylation agent, is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably 5% by mass or less, and even more preferably 2% by mass or less. The protective film-forming agent for silicon substrates according to this embodiment can exhibit the desired effect even if it contains only a silylation agent and a solvent.

[0034] (Other ingredients)

[0035] The protective film-forming agent for silicon substrates according to this embodiment may contain other components besides those listed above. Examples of other components include pH adjusters such as organic acids and amines. Preferred organic acids include acetic acid, citric acid, phosphoric acid, sulfuric acid, and methanesulfonic acid. More preferred amines include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), ammonia (NH3), ethylenediamine, diethylenetriamine, and triethanolamine.

[0036] <Processing method for silicon-based substrates>

[0037] The protective film-forming agent for silicon-based substrates according to this embodiment can be suitably used in methods for processing silicon-based substrates. A suitable example of a method for processing silicon-based substrates according to this embodiment is: (1) A step of applying an oxidation treatment to the surface of a silicon-based substrate containing an organic film in which at least a portion is exposed, (2) The step of contacting at least a portion of the surface of an oxidized silicon substrate with a protective film-forming agent for silicon substrates to form a protective film, A protective film-forming agent for silicon-based substrates is a method for treating silicon-based substrates that includes a silylation agent and a solvent having a Hildebrand SP value of 17.5 or less.

[0038] The silicon-based substrate protective film forming agent used in the silicon-based substrate processing method according to this embodiment can appropriately adopt the above-described components, characteristics, and conditions, and redundant explanations will be omitted. Furthermore, the protective film formed in the silicon-based substrate processing method according to this embodiment may be used as an etching protective film, for example.

[0039] According to the silicon substrate processing method of this embodiment, for example, by using the above-described protective film forming agent for silicon substrates, a protective film consisting of organic silyl groups can be formed on the silicon substrate without damaging the resist.

[0040] In the silicon-based substrate processing method according to this embodiment, the silicon-based substrate used is preferably one or more selected from the group consisting of silicon oxide, carbon-containing silicon oxide, silicon nitride, silicon carbide, silicon carbonitride, silicon oxynitride, silicon oxycarbonitride, and silicon.

[0041] (1) The process involves applying an oxidation treatment to the exposed portion of a silicon-based substrate on which a patterned organic film is present on the surface and at least a portion of it is exposed. Examples of the exposed organic film include photoresist. The oxidation treatment method is not particularly limited and can be carried out by, for example, oxidation treatment with a hydrogen peroxide-containing chemical solution or ozonated water. Before and after the process of (1), pre-treatment and post-treatment such as HF washing and water washing may be performed as needed. By performing the oxidation treatment, for example, a silicon dioxide (SiO2) film can be formed, which improves the reactivity with the protective film forming material.

[0042] (2) The step is preferably a step of immersing a protective film-forming agent for silicon substrates into at least a portion of the surface of the silicon substrate that has been oxidized, thereby forming a protective film. As for the method of immersing the silicon substrate protective film-forming agent, for example, a method called the wet method is preferred. Compared to the so-called vapor method, in which the protective film-forming agent for silicon substrates is vaporized and brought into contact with the substrate, this method is superior in that it can form a protective film with higher protective capacity on the silicon substrate.

[0043] (2) The immersion conditions for the process are not particularly limited, but for example, the immersion temperature is 20 to 60°C. The lower limit of the immersion temperature may be 25°C or higher, or 30°C or higher. The upper limit of the immersion temperature may be 45°C or lower, and the immersion time is 1 to 30 minutes as an example. The upper limit of the immersion time may be 20 minutes or less, 15 minutes or less, or 10 minutes or less.

[0044] <Processing method for silicon-based substrates>

[0045] The protective film-forming agent for silicon-based substrates and the method for processing silicon-based substrates according to this embodiment can be suitably used in semiconductor device manufacturing methods. A suitable example of a semiconductor device manufacturing method according to this embodiment is: (1) A step of applying an oxidation treatment to the surface of a silicon-based substrate containing an organic film in which at least a portion is exposed, (2) The step of contacting at least a portion of the surface of an oxidized silicon substrate with a protective film-forming agent for silicon substrates to form a protective film, A method for manufacturing semiconductor devices comprising a silylation agent and a solvent having a Hildebrand SP value of 17.5 or less, is used as a protective film-forming agent for silicon-based substrates.

[0046] The silicon-based substrate protective film forming agent used in the silicon-based substrate processing method according to this embodiment can appropriately adopt the above-described components, characteristics, and conditions, and redundant explanations will be omitted. Similarly, redundant explanations of the silicon-based substrate processing method according to this embodiment will be omitted.

[0047] It is preferable that the silicon-based substrate is one or more selected from the group consisting of silicon oxide, carbon-containing silicon oxide, silicon nitride, silicon carbide, silicon carbonitride, silicon oxynitride, silicon oxycarbonitride, and silicon.

[0048] (1) Examples of protective films formed in the process include those used as etching protective films.

[0049] (2) The step is preferably a step of immersing a protective film-forming agent for silicon substrates into at least a portion of the surface of the silicon substrate that has been oxidized, thereby forming a protective film. As for the method of immersing the silicon substrate protective film-forming agent, as mentioned above, a method called the wet method is preferred. Compared to the so-called vapor method, in which the protective film-forming agent for silicon substrates is vaporized and brought into contact with the substrate, this method is superior in that it can form a stronger protective film on the silicon substrate without damaging the resist.

[0050] The method for manufacturing a semiconductor device according to this embodiment preferably further includes a step of etching the silicon-based substrate on which the protective film has been formed after step (2). The etching method is not particularly limited and known methods can be used, for example, wet etching using aqueous solutions of acids or bases such as hydrofluoric acid, nitric acid, sulfuric acid, phosphoric acid, and TMAH (tetramethylammonium hydroxide), and dry etching using reactive ions. Furthermore, after the etching step, post-treatment such as IPA (isopropyl alcohol) washing or water washing may be performed as needed.

[0051] As described above, according to the protective film-forming agent for silicon-based substrates, the method for processing silicon-based substrates, and the method for manufacturing semiconductor devices according to this embodiment, a protective film can be formed on a silicon-based substrate without damaging the resist. As a result, it is expected that it will be possible to manufacture semiconductor devices with excellent etching selectivity, wiring pattern accuracy, and other properties. [Examples]

[0052] The present invention will be described in more detail by the following examples and comparative examples, but the present invention is not limited in any way by the following examples. Unless otherwise specified, the figures in these examples are based on mass.

[0053] <Preparation of protective film-forming agents for silicon-based substrates>

[0054] Protective film-forming agents for silicon-based substrates were prepared with the compositions shown in Table 2. For example, Example 1 is a protective film-forming agent for silicon-based substrates containing 7% by mass of TMSDMA (trimethylsilyldimethylamine) and decane as the solvent for the remainder. The Hildebrand SP value of decane is 15.7.

[0055] <Ingredients used>

[0056] The abbreviations and other terms listed in each table are as follows: HMDS: Hexamethyldisilazane TMSDMA: Trimethylsilyldimethylamine BDMADMS: Bisdimethylaminodimethylsilane • PGMEA: Propylene glycol monomethyl ether acetate (thinner-type solvent)

[0057] <Measuring film thickness>

[0058] The film thickness was measured using spectroscopic ellipsometry (JAWoollam Japan, "M-2000(registered trademark)UI").

[0059] <Evaluation of resist dissolution inhibition>

[0060] A resist solution (Tokyo Ohka Kogyo Co., Ltd., line-use positive type KrF resist, product name "TDUR-P3435") was applied to a silicon substrate (Si substrate), and then baked at 100°C for 60 seconds to form a resist layer. This layer was cut into 1cm x 2cm sections to obtain samples. The resist film thickness of these samples was then measured (film thickness before processing). Next, each sample was immersed in the silicon-based protective film-forming agent for each example and comparative example for 10 minutes, then rinsed with water to obtain the post-treatment sample. The film thickness of the resist in the post-treatment sample was then measured (post-treatment film thickness). The amount of resist film loss was determined from the pre-treatment film thickness and post-treatment film thickness, and the solubility of the resist was evaluated based on the following criteria. A: The amount of resist film thinning was less than 2 nm. B: The amount of resist film thinning was 2 nm or more.

[0061] <Evaluation of etching protection ability>

[0062] The etching protection capabilities of SiO2 and SiN were evaluated according to the following procedure.

[0063] (1) Sample preparation A laminated substrate was obtained by forming an SiO2 film or a SiN film on a silicon substrate (Si substrate) using the PVD method. This was then cut into 1cm x 2cm sections to obtain samples. First, the film thickness of these samples was measured (film thickness before treatment).

[0064] (2) Pretreatment Next, as a pretreatment, the sample was immersed in 0.5% by mass hydrofluoric acid (HF water) for 1 minute, then washed and dried. After that, it was heated to 50°C and immersed in SC1 (Standard Clean 1:NH4OH:H2O2:H2O = 1:1:50 mass ratio washing solution) for 1 minute, then washed with water and dried.

[0065] (3-1) Protective film formation treatment (vapor treatment) For vaporization, the following procedure was followed: The pre-treated sample was placed in a chamber, and the chamber was purged with nitrogen gas. Then, the sample was heated to 90°C, and vaporized hexamethyldisilazane (HMDS, see Comparative Example 1) was sprayed onto the sample for 60 seconds. After that, the sample was immersed in 0.5% by mass hydrogen fluoride solution (HF water) for 1 minute, washed with water, and dried. The film thickness of this sample was then measured (film thickness after treatment).

[0066] (3-2) Protective film formation treatment (wet treatment) For wet treatment, the following procedure was followed. The pre-treated samples were immersed for 3 minutes at the treatment temperature shown in Table 2 in beakers containing the silicon-based protective film-forming agent for each example and comparative example. After that, the samples were washed with decane (organic solvent) and dried by blowing with nitrogen gas. They were then immersed in 0.5% by mass hydrogen fluoride solution (HF water) for 1 minute, rinsed with water, and dried. The film thickness of these samples was then measured (film thickness after treatment).

[0067] (4) Evaluation of etching protection ability The amount of etching was determined from the film thickness before and after treatment, and the etching protection capacity was evaluated based on the following criteria. A: Compared to the condition without protective film-forming agent treatment, the amount of etching decreased by 0-50% with protective film-forming agent treatment. B: Compared to the condition without protective film-forming agent treatment, the amount of etching decreased by 51-80% with protective film-forming agent treatment. C: Compared to the condition without protective film-forming agent treatment, the amount of etching decreased by 81-100% with protective film-forming agent treatment.

[0068] Table 2 shows the composition and evaluation results for each example and comparative example. Note that the "mixing ratio" for "solvent" in the table is a volume ratio. For example, "decane + butyl acetate (mixing ratio 7:3)" in Example 6 means a mixed solvent containing decane and butyl acetate in a volume ratio of 7:3.

[0069] [Table 2]

[0070] From the above, it has been confirmed that the protective film-forming agent for silicon-based substrates according to this embodiment exhibits excellent resist dissolution suppression and etching protection capabilities. Furthermore, it has been confirmed that by using the protective film-forming agent for silicon-based substrates according to this embodiment, a protective film can be formed on a silicon-based substrate without damaging the resist.

Claims

1. A protective film-forming agent for silicon-based substrates, comprising a silylation agent and a solvent having a Hildebrand SP value of 17.5 or less.

2. The silylation agent is at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyldimethylamine, and bisdimethylaminodimethylsilane. A protective film-forming agent for silicon-based substrates according to claim 1.

3. The solvent is at least one selected from the group consisting of hydrocarbon solvents, ester solvents having one ester bond in their molecule, and ether solvents having one ether bond in their molecule. A protective film-forming agent for silicon-based substrates according to claim 1 or 2.

4. The content of the silylation agent is 1% by mass or more and 20% by mass or less. A protective film-forming agent for silicon-based substrates according to claim 1 or 2.

5. The total amount of hydrocarbon solvents, ester solvents having one ester bond in their molecule, and ether solvents having one ether bond in their molecule, in the total amount of the aforementioned solvent, is 80% by mass or more and 100% by mass or less. A protective film-forming agent for silicon-based substrates according to claim 1 or 2.

6. In the aforementioned protective film-forming agent for silicon-based substrates, the total content of the silylation agent and the solvent is 80% by mass or more and 100% by mass or less. A protective film-forming agent for silicon-based substrates according to claim 1 or 2.

7. A protective film can be formed on a silicon-based substrate containing an organic film that is at least partially exposed. A protective film-forming agent for silicon-based substrates according to claim 1 or 2.

8. (1) A step of applying an oxidation treatment to the surface of a silicon-based substrate containing an organic film in which at least a portion is exposed, (2) The step of contacting at least a portion of the surface of the silicon-based substrate that has been subjected to the oxidation treatment with a protective film-forming agent for silicon-based substrates to form a protective film, The aforementioned protective film-forming agent for silicon-based substrates comprises a silylation agent and a solvent having a Hildebrand SP value of 17.5 or less. Processing method for silicon-based substrates.

9. The (2) step is a step of immersing the silicon substrate protective film forming agent in at least a portion of the surface of the silicon substrate that has been subjected to the oxidation treatment, thereby forming the protective film. The method for processing a silicon-based substrate according to claim 8.

10. The silicon-based substrate is one or more selected from the group consisting of silicon oxide, carbon-containing silicon oxide, silicon nitride, silicon carbide, silicon carbonitride, silicon oxynitride, silicon oxycarbonitride, and silicon. A method for processing a silicon-based substrate according to claim 8 or 9.

11. (1) A step of applying an oxidation treatment to the surface of a silicon-based substrate containing an organic film in which at least a portion is exposed, (2) The step of contacting at least a portion of the surface of the silicon-based substrate that has been subjected to the oxidation treatment with a protective film-forming agent for silicon-based substrates to form a protective film, The aforementioned protective film-forming agent for silicon-based substrates comprises a silylation agent and a solvent having a Hildebrand SP value of 17.5 or less. A method for manufacturing semiconductor devices.

12. The (2) step is a step of immersing the silicon substrate protective film forming agent in at least a portion of the surface of the silicon substrate that has been subjected to the oxidation treatment, thereby forming the protective film. A method for manufacturing a semiconductor device according to claim 11.

13. After step (2) above, The process further includes etching the silicon-based substrate on which the protective film is formed. A method for manufacturing a semiconductor device according to claim 11 or 12.

14. The silicon-based substrate is one or more selected from the group consisting of silicon oxide, carbon-containing silicon oxide, silicon nitride, silicon carbide, silicon carbonitride, silicon oxynitride, silicon oxycarbonitride, and silicon. A method for manufacturing a semiconductor device according to claim 11 or 12.

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