JP4761055B2 - Pattern formation method - Google Patents

Description

  The present invention relates to microfabrication in a manufacturing process of a semiconductor element or the like, and more particularly to a pattern forming method in immersion photolithography in which an ArF excimer laser having a wavelength of 193 nm is used as a light source and a liquid such as water is inserted between a projection lens and a wafer.

In recent years, with the higher integration and higher speed of LSIs, there is a demand for finer pattern rules. In light exposure currently used as a general-purpose technology, the intrinsic resolution limit derived from the wavelength of the light source Is approaching. As exposure light used for forming a resist pattern, light exposure using a g-ray (436 nm) or i-line (365 nm) of a mercury lamp as a light source has been widely used. As a means for further miniaturization, a method of shortening the exposure wavelength is effective, and for mass production processes after 64 Mbit (process size is 0.25 μm or less) DRAM (Dynamic Random Access Memory). As a light source for exposure, a short wavelength KrF excimer laser (248 nm) was used in place of i-line (365 nm). However, in order to manufacture DRAMs with a density of 256M and 1G or more that require finer processing technology (processing dimensions of 0.2 μm or less), a light source with a shorter wavelength is required, and an ArF excimer has been used for about 10 years. Photography using a laser (193 nm) has been studied in earnest. Initially, ArF lithography was supposed to be applied from the device fabrication of the 180 nm node, but KrF excimer lithography was extended to 130 nm node device mass production, and full-scale application of ArF lithography is from the 90 nm node. Further, a 65 nm node device is being studied in combination with a lens whose NA is increased to 0.9. For the next 45 nm node device, the exposure wavelength has been shortened, and F ₂ lithography with a wavelength of 157 nm was nominated. However, various factors such as an increase in the cost of the scanner by using a large amount of expensive CaF ₂ single crystal for the projection lens, a change in the optical system due to the introduction of a hard pellicle because the durability of the soft pellicle is extremely low, and a reduction in resist etching resistance Because of this problem, it was proposed to postpone F ₂ lithography and early introduction of ArF immersion lithography (Non-patent Document 1: Proc. SPIE Vol. 4690 xxix).

  In ArF immersion lithography, it has been proposed to impregnate water between the projection lens and the wafer. The refractive index of water at 193 nm is 1.44, and it is possible to form a pattern using a lens having an NA of 1.0 or more. Theoretically, the NA can be increased to 1.44. The resolution is improved by the improvement of NA, and the possibility of a 45 nm node is shown by a combination of a lens of NA 1.2 or higher and strong super-resolution technology (Non-patent Document 2: Proc. SPIE Vol. 5040 p724).

  Here, there is a problem that water may enter the wafer edge or the back surface by inserting water between the wafer and the projection lens. In order to prevent contamination of the apparatus, it is necessary to clean the back surface and edge of the wafer with a solvent during spin coating. However, particularly when a highly hydrophilic substrate surface is exposed at the wafer edge, water cannot adhere to this portion. In this case, an extra process for removing the water adhering to the substrate surface is required, and if the water adhering to the wafer adheres to other than the exposure stage, it causes a trouble of the apparatus. Although it is conceivable to use a protective film having high water repellency without cleaning the edge, it is not practical considering the possibility of contamination of the device from the edge portion. It is necessary to increase the water repellency of the substrate itself.

  As a method for increasing the water repellency of the wafer surface, wafer surface treatment with a vapor prime of hexamethyldisilazane (HMDS) is widely performed. However, HMDS processing is not originally intended for immersion exposure, and it is necessary to develop a wafer processing method that further improves water repellency.

Proc. SPIE Vol. 4690 xxix Proc. SPIE Vol. 5040 p724

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pattern forming method that enables good immersion lithography by preventing water from remaining on and wrapping around the wafer edge and backside after exposure. .

  As a result of intensive investigations to achieve the above object, the present inventors use a substrate with improved water repellency so that the contact angle with water is 75 degrees or more. In this case, means for increasing water repellency In particular, by using a substrate with improved water repellency by applying a silylating agent having an alkyl group or an alkenyl group substituted with fluorine, there is no remaining or wraparound of water on the wafer edge or back surface after exposure. As a result, the present invention has been made.

（ここで、一般式（１）中、Ｒ ¹ 〜Ｒ ³ 、Ｒ ⁵ 〜Ｒ ⁷ は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、炭素数２〜１０の直鎖状、分岐状又は環状のアルケニル基、又は炭素数６〜１０のアリール基であって、Ｒ ¹ 〜Ｒ ³ 及びＲ ⁵ 〜Ｒ ⁷ の内少なくとも１つはフッ素で置換されている。Ｒ ⁴ は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、又は−ＳｉＲ ¹ Ｒ ² Ｒ ³ である。あるいは、Ｒ ² とＲ ⁶ は結合して環を形成してもよい。ａは１〜１０の整数である。
一般式（２）中、Ｒ ⁸ は水素原子、又は炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基で少なくとも１個以上のフッ素原子を含む。Ｒ ⁹ 、Ｒ ¹⁰ 、Ｒ ¹¹ は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、炭素数１〜１０の直鎖状、分岐状又は環状のアルコキシ基、又は直鎖状、分岐状又は環状の炭素数２〜１０のアルケニル基であり、フッ素で置換されていてもよい。ｂ及びｃは１〜３の整数であり、ｂ＋ｃ＝４である。
一般式（３）中、Ｒ ¹² は水素原子、又は炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基で少なくとも１個以上のフッ素原子を含む。Ｒ ¹³ は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、又は直鎖状、分岐状又は環状の炭素数２〜１０のアルケニル基であり、フッ素で置換されていてもよい。Ｘは酸素原子又はＣＨ ₂ である。ｄ及びｅは１〜３の整数であり、ｄ＋ｅ＝４である。）
請求項２：
基板表面を、フッ素で置換されたアルキル基又はアルケニル基を有する上記シリル化剤及びフッ素非置換のアルキル基又はアルケニル基を有するシリル化剤との混合シリル化剤で処理することによって高撥水性とした基板を用いることを特徴とする請求項１記載のパターン形成方法。
請求項３：
フッ素非置換のアルキル基又はアルケニル基を有するシリル化剤が、下記一般式（４）、（５）又は（６）で示されるものである請求項２記載のパターン形成方法。

（ここで、一般式（４）中、Ｒ ²¹ 〜Ｒ ²³ 、Ｒ ²⁵ 〜Ｒ ²⁷ は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、炭素数２〜１０の直鎖状、分岐状又は環状のアルケニル基、又は炭素数６〜１０のアリール基である。Ｒ ²⁴ は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、又は−ＳｉＲ ²¹ Ｒ ²² Ｒ ²³ である。あるいは、Ｒ ²² とＲ ²⁶ は結合して環を形成してもよい。ａは１〜１０の整数である。
一般式（５）中、Ｒ ²⁸ は水素原子、又は炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基である。Ｒ ²⁹ 、Ｒ ³⁰ 、Ｒ ³¹ は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、炭素数１〜１０の直鎖状、分岐状又は環状のアルコキシ基、又は直鎖状、分岐状又は環状の炭素数２〜１０のアルケニル基である。ｂ及びｃは１〜３の整数であり、ｂ＋ｃ＝４である。
一般式（６）中、Ｒ ³² は水素原子、又は炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基である。Ｒ ³³ は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、又は直鎖状、分岐状又は環状の炭素数２〜１０のアルケニル基である。Ｘは酸素原子又はＣＨ ₂ である。ｄ及びｅは１〜３の整数であり、ｄ＋ｅ＝４である。）
請求項４：
液浸リソグラフィーが、１８０〜２５０ｎｍの範囲の露光波長を用い、投影レンズとウエハーの間に水を挿入させたものである請求項１乃至３のいずれか１項記載のパターン形成方法。
請求項５：
レジスト膜上にトップコートとしてレジスト保護膜を形成した請求項１乃至４のいずれか１項記載のパターン形成方法。 That is, the present invention provides the following pattern forming method.
Claim 1:
In a pattern formation method by immersion lithography in which a resist film formed on a substrate is exposed in a liquid, the substrate is an alkyl substituted with fluorine represented by the following general formula (1), (2) or (3) A pattern forming method comprising using a highly water-repellent substrate having a contact angle with water treated with a silylating agent having a group or an alkenyl group of 75 ° or more.

(Here, in general formula (1), R < ¹ > -R < ³ > , R < ⁵ > -R < ⁷ > is a hydrogen atom, a C1-C10 linear, branched or cyclic alkyl group, C2-C10. A linear, branched or cyclic alkenyl group or an aryl group having 6 to 10 carbon atoms, wherein at least one of R ^{1 to} R ³ and R ^{5 to} R ⁷ is substituted with fluorine. ⁴ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or —SiR ¹ R ² R ³ , or R ² and R ⁶ are combined to form a ring. A is an integer of 1 to 10.
In the general formula (2), R ⁸ is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms and contains at least one fluorine atom. R ⁹ , R ¹⁰ and R ¹¹ are each a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 10 carbon atoms, or a straight chain. It is a chain, branched or cyclic alkenyl group having 2 to 10 carbon atoms and may be substituted with fluorine. b and c are integers of 1 to 3, and b + c = 4.
In the general formula (3), R ¹² comprises a hydrogen atom, or a straight, at least one fluorine atom in the branched or cyclic alkyl group. R ¹³ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or a linear, branched or cyclic alkenyl group having 2 to 10 carbon atoms, which is substituted with fluorine. May be. X is an oxygen atom or CH ₂ . d and e are integers of 1 to 3, and d + e = 4. )
Claim 2 :
High water repellency is obtained by treating the substrate surface with a mixed silylating agent of the above silylating agent having an alkyl or alkenyl group substituted with fluorine and a silylating agent having a fluorine-unsubstituted alkyl or alkenyl group. The pattern forming method according to claim 1, wherein a patterned substrate is used.
Claim 3 :
The pattern forming method according to claim 2, wherein the silylating agent having a fluorine-unsubstituted alkyl group or alkenyl group is represented by the following general formula (4), (5) or (6).

(Here, in the general formula (4), R ^{21 to} R ²³ and R ^{25 to} R ²⁷ are hydrogen atoms, linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms, and those having 2 to 10 carbon atoms. A linear, branched or cyclic alkenyl group, or an aryl group having 6 to 10 carbon atoms, R ²⁴ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or — SiR ²¹ R ²² R ^23. Alternatively, R ²² and R ²⁶ may combine to form a ring, and a is an integer of 1 to 10.
In the general formula (5), R ²⁸ is a hydrogen atom, or a straight, a branched or cyclic alkyl group. R ²⁹ , R ³⁰ and R ³¹ are each a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 10 carbon atoms, or a straight chain It is a chain, branched or cyclic alkenyl group having 2 to 10 carbon atoms. b and c are integers of 1 to 3, and b + c = 4.
In general formula (6), ^R32 is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. R ³³ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or a linear, branched or cyclic alkenyl group having 2 to 10 carbon atoms. X is an oxygen atom or CH ₂ . d and e are integers of 1 to 3, and d + e = 4. )
Claim 4 :
Immersion lithography using an exposure wavelength in the range of 180 to 250 nm, the projection lens and the pattern forming method of any one of claims 1 to 3 is obtained by inserting the water during the wafer.
Claim 5 :
5. The pattern forming method according to claim 1, wherein a resist protective film is formed as a top coat on the resist film.

  The pattern forming method by immersion lithography according to the present invention can prevent water remaining or wraparound after exposure on the wafer edge or back surface by using a substrate with improved water repellency.

  In the pattern forming method of the present invention, typically, a resist film is formed on a substrate, and preferably a resist protective film (top coat) is formed on the substrate, and then in a liquid such as water by KrF or ArF immersion lithography. (Preferably in water). After exposure, post-exposure baking (PEB) is performed. If necessary, the resist protective film is removed, followed by development with a developer. A resist pattern is formed by immersion lithography. To do. In this case, the resist film may be formed directly on the substrate, or may be formed through an antireflection film, a lower layer film, a silicon-containing intermediate film, or the like. For example, an organic antireflection film, a photoresist film, and in some cases, a resist protective film is applied and formed on the substrate. For coating, a spin coating method is generally used. Instead of the organic antireflection film, an organic underlayer film used in a multilayer process and a silicon-containing intermediate film may be applied and formed in this order, and a photoresist may be applied and formed thereon. The resist protective film can be removed simultaneously with the development of the resist film. As the above-described immersion lithography method and conditions, known methods and conditions can be adopted, but an exposure wavelength in the range of 180 to 250 nm is used, and water is inserted between the projection lens and the wafer. In addition, known materials such as a resist material and a resist protective film forming material can be used, but are not limited thereto.

  In this case, in the present invention, it is preferable to form a resist protective film (topcoat) on the resist film. As the polymer for the topcoat, an alcohol polymer having an α-trifluoromethyl group or a carboxyl group is used. A polymer having an alkali-soluble group can be used as a base polymer. Specifically, it can be exemplified below.

In the pattern forming method by immersion lithography as described above, the present invention uses a highly water-repellent substrate having a contact angle with water of 75 ° or more, preferably 80 ° or more, as the substrate.
Here, as the substrate _{material, Si, SiO 2, SiON,} SiN, p-Si, α-Si, W, W-Si, Al, Cu, Al-Si , etc., various low dielectric (Low-k) film And the stopper film | membrane can be used.

  In the present invention, a substrate having such a substrate that has been subjected to water repellency treatment to increase water repellency is used. As the water repellency treatment method, silyl having an alkyl group or an alkenyl group substituted with fluorine is particularly used. It is preferable to use a substrate having improved water repellency by applying a chemical agent. As described above, in order for the substrate to repel water efficiently, the contact angle with water needs to be 75 degrees or more, more preferably 80 degrees or more. Moreover, although the upper limit is not restrict | limited, Usually, it is 120 degrees or less, especially 110 degrees or less.

（一般式（１）中、Ｒ¹〜Ｒ³、Ｒ⁵〜Ｒ⁷は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、炭素数２〜１０の直鎖状、分岐状又は環状のアルケニル基、又は炭素数６〜１０のアリール基であって、Ｒ¹〜Ｒ³及びＲ⁵〜Ｒ⁷の内少なくとも１つはフッ素で置換されている。Ｒ⁴は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、又は−ＳｉＲ¹Ｒ²Ｒ³である。あるいは、Ｒ²とＲ⁶は結合して環を形成してもよい。ａは１〜１０の整数である。
一般式（２）中、Ｒ⁸は水素原子、又は炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基で少なくとも１個以上のフッ素原子を含む。Ｒ⁹、Ｒ¹⁰、Ｒ¹¹は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、炭素数１〜１０の直鎖状、分岐状又は環状のアルコキシ基、又は直鎖状、分岐状又は環状の炭素数２〜１０のアルケニル基であり、フッ素で置換されていてもよい。ｂ及びｃは１〜３の整数であり、ｂ＋ｃ＝４である。
一般式（３）中、Ｒ¹²は水素原子、又は炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基で少なくとも１個以上のフッ素原子を含む。Ｒ¹³は水素原子、炭素数１〜１０の直鎖状、分岐状又は環状のアルキル基、又は直鎖状、分岐状又は環状の炭素数２〜１０のアルケニル基であり、フッ素で置換されていてもよい。Ｘは酸素原子又はＣＨ₂である。ｄ及びｅは１〜３の整数であり、ｄ＋ｅ＝４である。） Here, the silylating agent having an alkyl group or alkenyl group substituted with fluorine is preferably selected from the following general formulas (1), (2), and (3).

(In the general formula (1), R ^{1 to} R ³ and R ^{5 to} R ⁷ are a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and a straight chain having 2 to 10 carbon atoms. , A branched or cyclic alkenyl group, or an aryl group having 6 to 10 carbon atoms, wherein at least one of R ^{1 to} R ³ and R ^{5 to} R ⁷ is substituted with fluorine, and R ⁴ is hydrogen. It is an atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or —SiR ¹ R ² R ³ , or R ² and R ⁶ may combine to form a ring. a is an integer of 1-10.
In the general formula (2), R ⁸ is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms and contains at least one fluorine atom. R ⁹ , R ¹⁰ and R ¹¹ are each a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 10 carbon atoms, or a straight chain. It is a chain, branched or cyclic alkenyl group having 2 to 10 carbon atoms and may be substituted with fluorine. b and c are integers of 1 to 3, and b + c = 4.
In the general formula (3), R ¹² comprises a hydrogen atom, or a straight, at least one fluorine atom in the branched or cyclic alkyl group. R ¹³ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or a linear, branched or cyclic alkenyl group having 2 to 10 carbon atoms, which is substituted with fluorine. May be. X is an oxygen atom or CH ₂ . d and e are integers of 1 to 3, and d + e = 4. )

Here, the alkyl group having 1 to 10 carbon atoms includes methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, octyl group. Group, decyl group and the like. Examples of the alkenyl group having 2 to 10 carbon atoms include vinyl group, allyl group, propenyl group, butenyl group, hexenyl group, and cyclohexenyl group. Examples of the aryl group having 6 to 10 carbon atoms include phenyl group, tolyl group, xylyl group, and naphthyl group. In addition, when R ² and R ⁶ are bonded to form a ring with a silicon atom to which R ² and R ⁶ are bonded, and further a nitrogen atom interposed between these silicon atoms, R ² and R ⁶ are combined. -(NR ⁴ )-is formed. In addition, although a is an integer of 1-10, Preferably it is 1-8. Furthermore, as a C1-C10 alkoxy group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group etc. are mentioned.
In the above formula, R ^{1 to} R ³ and R ^{6 to} R ⁸ may be the same or different from each other, and R ⁴ , R ⁸ , R ¹² , and R ^{9 to} R ¹¹ , R ¹³ may be When there are a plurality of each, they may be the same or different.

  The compound represented by the general formula (2) is proposed in JP-A-11-72922, and the compound represented by the general formula (3) is proposed in JP-A-9-102458.

Specific examples of the compound represented by the general formula (1) include the following.

Specific examples of the compound represented by the general formula (2) include the following.

Specific examples of the compound represented by the general formula (3) include the following.

Further, the silylating agent having a fluorinated alkyl group or alkenyl group is treated with a mixed silylating agent in which a silylating agent having a non-fluorinated (unfluorinated) alkyl group or alkenyl group is mixed. You can also. In this case, examples of the silylating agent having a fluorine-unsubstituted alkyl group or alkenyl group include those in which any of R ^{1 to} R ^{13 in} the above formulas (1) to (3) is fluorine-free. Examples include hexamethyldisilazane, hexaethyldisilazane, bisethyldimethyldisilazane, and bispropyldimethyldisilazane.

  When such a mixed silylating agent is used, the mixing ratio of the silylating agent having a fluorinated alkyl group or alkenyl group and the silylating agent having a fluorine-unsubstituted alkyl group or alkenyl group is the mixed silylating agent. In the agent, the mass ratio of the silylating agent having a fluorinated alkyl group or alkenyl group is 0.1 to 100%, more preferably 1 to 100%, still more preferably 5 to 100%. In addition, the silylating agent having a fluorine-unsubstituted alkyl group or alkenyl group, when blended, is 0.1 to 99.9%, particularly 1 to 99%, particularly 5 to 95% in the mixed silylating agent. It is preferable to do.

  As a method for treating a substrate with a silylating agent having a fluorinated alkyl group or alkenyl group or the mixed silylating agent in the pattern forming method of the present invention, when the silylating agent is liquid, the silylating agent solution is nitrogen. For example, a vapor prime method in which a gas bubbled by a method is blown onto a substrate is generally used. The treatment time is preferably in the range of 3 to 500 seconds. At this time, the substrate may be heated in the range of 30 to 300 ° C. with a hot plate or the like. When the silylating agent is a solid, it may be dissolved in a solvent and treated by a spin coating method. Before the silylation, the silylation efficiency can be increased by baking the substrate surface at a temperature of 30 to 400 ° C. for 3 to 500 seconds to evaporate moisture and adsorbed components on the substrate surface.

Since the silylating agent of the present invention has a fluorinated alkyl group or a fluorinated alkenyl group, it also has a feature that the resist protective film having a fluorinated alkyl group has excellent adhesion.
Furthermore, the silylating agent having a fluorinated alkyl group or alkenyl group of the present invention can be silylated by mixing with a silylating agent having a non-fluorinated alkyl group or alkenyl group. The coexistence of a fluoroalkyl group and an alkyl group makes it possible to further improve water repellency (XXIV FATIPEC Congress Book., Vol. B, p15-38 (1997)).

  That is, as shown in FIG. 1A, when top coat (resist protective film) 1 is applied to Si substrate 2, edge cleaning is performed, and when immersed in water, water enters the interface between top coat 1 and Si substrate 2. Then, the top coat 1 is peeled off. However, when the water-repellent treatment of the substrate is performed, the top coat 1 does not peel off as shown in FIG. Usually, in order to prevent elution into water from not only the resist film 3 but also the antireflection film 4, the lower layer film, and the silicon-containing intermediate film, the top coat 1 is used as shown in FIG. A laminated structure covering all the layers is effective, but in that case, the adhesion between the Si substrate and the top coat becomes a problem. However, the highly water-repellent substrate produced by the silylation method of the present invention also has a feature that can prevent the topcoat from peeling off. In the figure, 5 indicates water.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Examples and Comparative Examples]
A resist protective film was spin-coated on the Si substrate and baked at 100 ° C. for 60 seconds, and then a protective film having a thickness of 50 nm was formed. In addition, the following topcoat polymer was used as the resist protective film.

  In this case, the Si substrate was heated at 200 ° C. for 60 seconds, and 1,3-bis (3,3,3-trifluoropropyl) tetramethyldisilazane, 4-dimethyl (3,3,3-trifluoro) was used as an example. Methylpropyl) siloxy-3-penten-2-one, isopropenoxy-3,3,3-trifluoropropyldimethylsilane, 1,3-bis (3,3,3-trifluoropropyl) tetramethyldisilazane and hexamethyl A mixture of disilazane (HMDS) (mixing ratio (mass ratio) = 50: 50) and hexamethyldisilazane (HMDS) as a comparative example were heated to a substrate of 100 ° C. while being bubbled with nitrogen and vapor primed for 60 seconds.

  About 1 μL of water droplets were dropped on the wafer, and the contact angle was measured. Pure water was dropped on the entire surface of a 200 mm wafer with and without silane treatment and rotated at 200 rpm for 30 seconds to check whether water disappeared from the wafer. The results are shown in Table 1.

  A top coat solution was prepared by dissolving 1 g of the polymer for top coat shown above in 50 g of isobutyl alcohol. A top coat is spin-coated on the above substrate, the wafer edge width 5 mm is cleaned with a PGMEA (propylene glycol-1-monomethyl ether-2-acetate) solution, pre-baked at 100 ° C. for 60 seconds, and a top with a film thickness of 50 nm. A coat film was prepared. Next, water was dropped on the wafer edge portion and left for 60 seconds to visually observe the adhesion of the topcoat film. The results are shown in Table 2.

FIG. 2 is a partially omitted cross-sectional view of a state where a topcoat (resist protective film) is formed on a substrate and immersed in water, (A) is an example using a non-processed substrate, and (B) is a silylated substrate of the present invention (C) is an example in which an antireflection film, a resist film, and a topcoat are sequentially formed on the silylated substrate.

Explanation of symbols

1 Topcoat 2 Si substrate 3 Resist film 4 Antireflection film 5 Water

Claims (5)

In a pattern formation method by immersion lithography in which a resist film formed on a substrate is exposed in a liquid, the substrate is an alkyl substituted with fluorine represented by the following general formula (1), (2) or (3) A pattern forming method comprising using a highly water-repellent substrate having a contact angle with water treated with a silylating agent having a group or an alkenyl group of 75 ° or more.

(Here, in general formula (1), R < ¹ > -R < ³ > , R < ⁵ > -R < ⁷ > is a hydrogen atom, a C1-C10 linear, branched or cyclic alkyl group, C2-C10. A linear, branched or cyclic alkenyl group or an aryl group having 6 to 10 carbon atoms, wherein at least one of R ^{1 to} R ³ and R ^{5 to} R ⁷ is substituted with fluorine. ⁴ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or —SiR ¹ R ² R ³ , or R ² and R ⁶ are combined to form a ring. A is an integer of 1 to 10.
In the general formula (2), R ⁸ is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms and contains at least one fluorine atom. R ⁹ , R ¹⁰ and R ¹¹ are each a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 10 carbon atoms, or a straight chain. It is a chain, branched or cyclic alkenyl group having 2 to 10 carbon atoms and may be substituted with fluorine. b and c are integers of 1 to 3, and b + c = 4.
In the general formula (3), R ¹² comprises a hydrogen atom, or a straight, at least one fluorine atom in the branched or cyclic alkyl group. R ¹³ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or a linear, branched or cyclic alkenyl group having 2 to 10 carbon atoms, which is substituted with fluorine. May be. X is an oxygen atom or CH ₂ . d and e are integers of 1 to 3, and d + e = 4. ) High water repellency is obtained by treating the substrate surface with a mixed silylating agent of the above silylating agent having an alkyl or alkenyl group substituted with fluorine and a silylating agent having a fluorine-unsubstituted alkyl or alkenyl group. The pattern forming method according to claim 1, wherein a patterned substrate is used. The pattern forming method according to claim 2, wherein the silylating agent having a fluorine-unsubstituted alkyl group or alkenyl group is represented by the following general formula (4), (5) or (6).

(Here, R in the general formula (4) ^{twenty one} ~ R ^{twenty three} , R ^{twenty five} ~ R ²⁷ Is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms. is there. R ^{twenty four} Is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or -SiR ^{twenty one} R ^{twenty two} R ^{twenty three} It is. Or R ^{twenty two} And R ²⁶ May combine to form a ring. a is an integer of 1-10.
In general formula (5), R ²⁸ Is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. R ²⁹ , R ³⁰ , R ³¹ Is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 10 carbon atoms, or a linear, branched or cyclic group. An alkenyl group having 2 to 10 carbon atoms. b and c are integers of 1 to 3, and b + c = 4.
In general formula (6), R ³² Is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. R ³³ Is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or a linear, branched or cyclic alkenyl group having 2 to 10 carbon atoms. X is an oxygen atom or CH ₂ It is. d and e are integers of 1 to 3, and d + e = 4. ) Immersion lithography using an exposure wavelength in the range of 180 to 250 nm, the projection lens and the pattern forming method of any one of claims 1 to 3 is obtained by inserting the water during the wafer. 5. The pattern forming method according to claim 1, wherein a resist protective film is formed as a top coat on the resist film.

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