JPS60220340A - Photosensitive resin composition and formation of pattern - Google Patents

Abstract

PURPOSE:To obtain a negative type resist capable of undergoing dry treatment of a substrate and microfabrication with high resolution and high precision by incorporating a silicon-contg. resin having aromatic rings each having specified substituents on a part or the whole part of the ring, in a photosensitive resin compsn. CONSTITUTION:The silicon-contg. resin may be either of a polysiloxane or polysilane resin, and a polymer of phenylmethylsiloxane, etc., are used for an aromatic polysiloxane resin, and polydiphenylsilane, etc., are used for the polysilane resin. These resing having -CH2N3 group are used alone or together with a a sensitizer, such as aromatic ketones, and a cross-linking agent, such as divinyl compds., etc., as a photosensitive resin. Said sensitizer is used generally in an amt. of 3-20wt% of the silicon-contg. resin, and said cross-linking agent is used 5-25wt% of said resin. They are dissolved in a solvent, applied to the substrate, exposed, and developed to form a pattern. This pattern is used as a mask for treating the substrate to be microprocessed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a material for forming a fine resist pattern with high precision applicable to dry substrate processing and a method of using the same.

[Prior art]

Conventionally, in the production of minute electronic circuits or semiconductor devices, such as large-scale integrated circuit devices (LSI), a resist film made of a photosensitive polymer compound is provided on a substrate to be processed, and this is exposed to ultraviolet rays, X-rays, or electron beams. Alternatively, a method is used in which a resist pattern is formed on the substrate to be processed by drawing and exposing a desired pattern with an ion beam, etc., and then developing it.Furthermore, the processing of the substrate, that is, the fabrication of elements, protects this resist pattern. It has been used as a mask.

In processing the element, the formed resist pattern is used as a protective mask, so the dimensional accuracy and degree of miniaturization in processing depend on the resolution of the resist used. therefore,
In order to achieve good substrate processing, it is necessary to form an excellent resist pattern that has high resolution and sufficient durability as a protective mask during substrate processing.

In addition, in recent years, dry processing methods (dry etching methods) that can improve processing accuracy have been used to process substrates, such as plasma etching methods that use reactive gas plasma, reactive sputter etching methods, or ion etching methods that use inert gas ions. Law is becoming mainstream. Such a substrate processing method causes decomposition of the polymer constituting the resist pattern as well as etching the substrate, so a resist pattern with a large film thickness is required to perform highly accurate substrate processing. However, when forming a pattern with a thick resist, there are some effects such as swelling of the resist pattern during development, generation of standing waves during ultraviolet exposure, and pattern washing due to secondary electrons during electron beam or X-ray exposure. Therefore, it becomes difficult to obtain a pattern with higher resolution. In particular, these effects appear strongly in negative resists. In addition, the finer the drawing or pattern, the larger the resist pattern is required to ensure the film thickness necessary for processing, so the shape ratio is 1.
It is thought that negative resists, which are said to be difficult to form the above patterns, cannot be applied to the formation of fine patterns, especially microfabrication of 1 μm or less.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a negative resist that can be applied to dry substrate processing and that can realize high-resolution microfabrication with high accuracy, and a method for using the same.

[Structure of the invention]

To summarize the present invention, the first invention of the present invention relates to a photosensitive resin composition, which has an aromatic ring, and a part or all of the aromatic ring is represented by the formula: -011,k13. It is characterized by containing a silicon-containing resin having a substituent group.

The second invention of the present invention relates to a fine pattern forming method, in which an organic polymer film that is resistant to dry processing of the substrate is formed on a substrate to be processed, and a photosensitive film is further applied on the organic polymer film. A resist film is formed to have a two-layer structure, and then the upper resist layer is exposed to light, drawn, and developed to form a resist pattern on the upper layer.The upper resist pattern is used as a protective mask to form a resist pattern on the lower layer. A method for forming a resist pattern on a substrate to be processed by etching a polymer film with oxygen plasma, characterized in that the photosensitive resin composition of the first invention is used as the photosensitive resist.

The silicone-containing resin in the present invention may be either a polysiloxane resin or a polysilane resin.

Examples of the aromatic polysiloxane resin in the present invention include polymers of phenylmethylsiloxane, polymers of diphenylsiloxane, copolymers thereof, polyphenylsilsesquioxane, etc., in which some or all of the phenyl groups are monovalently added. 〇 H2N is introduced. can be built. The introduction ratio of these substituents may be arbitrary, but more preferably 5 molar ratio or more.

Examples of polysilane resins include aromatic polysilanes such as polydiphenylsilane, polymethylphenylsilane, and polymethylphenethylsilane, and monomers of alkylpolysilanes such as polymethylpropylsilane, polymethylbutylsilane, and polymethylhexylsilane. -OH, N to the copolymer of each monomer of aromatic polysilane and
One example is one in which three groups are introduced.

For polysilanes with chloromethylated aromatic groups,
As with polysiloxane, -an! N, a group can be introduced.

The polysiloxane resin and polysilane resin having the 10H, N group of the present invention described above can be used as they are to protect against ultraviolet rays.
Since it is sensitive to X-rays and ion beams, it can be used as a photosensitive resin, but it may also be used with the addition of sensitizers, cross-linking agents, etc., which is particularly effective when exposed to ultraviolet light. It is. Examples of sensitizers include aromatic ketones, aromatic nitro compounds, triphenylmethane dyes,
-dibenzoylme tyrene-3-methyl-β-naphthothiazoline, N-phenylthioacridone, 4-(4-amyloxy7enyl)-2,6-bis(4-methoxyphenyl)thiapyrylium perchlorate, etc. Can be mentioned.

Examples of the crosslinking agent include difunctional compounds such as various divinyl compounds and dihydroxy compounds. The amount of sensitizer and crosslinking agent depends on the fI of the exposure source! It is determined depending on the type I and the required sensitivity, but generally the sensitizer is 3.
~20% by weight and 1 ft% of the crosslinking agent is used in a mortar with a weight of 5 to 25%, giving good results from the viewpoint of resin film-forming properties. The photosensitive resin composition of the present invention is prepared by dissolving an aromatic polysiloxane resin or an aromatic polysilane resin having -0H,N3 groups in an organic solvent together with a sensitizer or a crosslinking agent as required, and applying this to a substrate to be processed. After coating, a pattern is formed by exposure and development, and the formed pattern is used as a mask to process the substrate.

The second aspect of the present invention relates to a pattern forming method that most effectively uses the photosensitive resin composition of the present invention. Briefly, first, an organic polymer film is formed on a substrate to be processed, which serves as a good mask material in dry processing of the substrate to be processed. On top of this, the photosensitive resin composition of the present invention is applied so as not to mix with the organic polymer film to form a two-layer resist film. This is exposed and drawn with ultraviolet light, X-rays, electron beams, ion beams, etc., and developed to form a pattern of the photosensitive resin composition. Next, the organic polymer film is etched using oxygen plasma using the pattern as a mask, and the pattern is transferred to the organic polymer film. At this time, since the main chain of the photosensitive resin composition of the present invention is composed of polysiloxane or polysilane, the etching rate in oxygen plasma is extremely low, and the photosensitive resin composition of the present invention can be easily etched even when the underlying organic polymer film is thick. Highly accurate etching becomes possible. Additionally, the photosensitive resin composition of the present invention has a highly photosensitive azide group and at the same time has a main chain consisting of a polysiloxane or polysilane structure. It has high resistance to oxygen plasma when etching, and can perform highly accurate etching even when the film thickness of the photosensitive resin composition is thin.
An organic polymer film pattern with a large shape ratio can be formed on the substrate to be processed. Since the substrate to be processed is processed using the organic polymer film pattern as a mask, a large shape ratio is advantageous for the processing person. In addition, since the film thickness of the photosensitive resin composition can be made thinner, the generation of standing waves in ultraviolet exposure, the blurring of patterns due to secondary electrons in electron beams or X-ray beams, and the shallow ion penetration distance in ion beam exposure can be avoided. Good, it has the advantage of less pattern deformation due to swelling during development.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The invention is not limited to these examples.

Examples 1 to 3 Chloromethylated polymethylphenylsiloxane (molecular weight 120,000, chloromethyl group content 15 mol%) (Example 1)
, chloromethylated polydiphenylsiloxane (molecular weight 1
70,000, chloromethyl group content 21 mol%) (Example 2),
Chloromethylated polysilsesquioxane (molecular weight 2,1
100,000 and chloromethyl group content 72 mol%) (Example 3) were prepared and reacted under the following conditions. Each polymer was finely ground and dispersed in 100-hexane. To this were added 1.4 f of tetrabutylphosphonium bromide and 2.5 t of potassium azide, and the mixture was vigorously stirred at 30°C for 48 hours.

Thereafter, the reaction solution was poured into methanol and the polymer was separated. The synthesized polymer was purified by dissolving it in tetrahydrofuran, reprecipitating it in water and methanol, and then drying it in vacuum. Table 1 summarizes the synthesis results of each polymer.

Table 1 Note that the content of -(!H2N3 groups was calculated from the decreased chlorine content.

Examples 4 to 5 Chloromethylated copolymer of dimethylsilane and methylphenylsilane (molecular weight 125,000, chloromethyl group content 25 mol) (Example 4), chloromethylated polymethylphenylsilane ( Published 1 & 50,000, chloromethyl group content: 34 moles) (Example 5), respectively 10? A sample was prepared, and the chloromethyl group was subjected to azide methylation in the same manner as in Example 1. The results are summarized in Table 2.

Table 2 Examples 6 to 8 Each of the polymers synthesized in Examples 1 to 5 was coated on a silicon substrate (18 μm thick) and exposed to ultraviolet light (100 Wxe-
lamp) (Example 6), electron beam (acceleration voltage 2okv) (
Example 7), xllQ (81-K” line wavelength y, 15
A) Table 3 shows the sensitivity (exposure 11 required to leave 50% of the initial film thickness on the silicon substrate after development) at each exposure time in (Example 8).

Table 5 Examples 9 to 10 5 parts by weight of 2-nitrofluorenone as a sensitizer were added to the polymer obtained in Example 3 and coated on a silicon substrate to a thickness of 08 μm (Example 9) and the sensitizer 5% by weight of 2-nitrofluorenone and 5% by weight of triallyl 7 anurate as a crosslinking agent were coated on a silicon substrate to a thickness of 18 μm (Example 10), and irradiated with ultraviolet light in the same manner as in Example 6. Sensitivity was measured. The results are shown in Table 4.

Table 4 Example 11 AZ-1550J (manufactured by Sibley) photoresist was applied to a thickness of 1 μm on a silicon substrate and cured by heat treatment at 200° C. for 60 minutes. On top of this, 5% by weight of 2-nitrofluorenone was added as a sensitizer to the polymer obtained in Example 2, and 4047n of high-pressure mercury lamp was used by the contact mask method.
It was exposed to light of m. After development, AZ-13505 was etched with oxygen gas by a reactive sputter etching method. Etching was carried out at an oxygen gas pressure of 60 millitorr, an oxygen gas flow rate of 5.05 ccxn, and an I'IF power of 0. I W/c
rn! I went there. After etching for about 12 minutes, the pattern was observed and found that a 17 μm line and space pattern could be formed on the substrate.

〔Effect of the invention〕

As explained above, since the photosensitive resin composition of the present invention contains a material having -OH, N3 groups in the aromatic group of aromatic polysiloxane or aromatic polysilane, it has high photosensitivity and can be treated with oxygen plasma. Highly resistant to. In particular, aromatic-substituted --H,N, groups can be sensitized by exposure to ultraviolet light, and high sensitivity can be obtained when used as a photoresist.

Furthermore, due to its high resistance to oxygen plasma, it can be used as a resist film with a two-layer structure, and high resolution can be obtained.

Claims (1)

[Claims] 1. A photosensitive material comprising a silicon-containing resin having an aromatic ring and having a substituent represented by the formula: -OH,N on part or all of the aromatic ring. resin composition. 2. Claim 1, wherein the silicone-containing resin is obtained by azizing some or all of the chloromethyl groups of a silicone-containing resin having a chloromethylated aromatic ring. The photosensitive resin composition described in . (5) The photosensitive resin composition according to claim 1 or 2, wherein the silicon-containing resin is a polysiloxane resin or a polysilane resin. 4. An organic polymer film that is resistant to dry processing of the substrate is formed on the substrate to be processed, and a photosensitive resist film is further formed on top of the organic polymer film to form a two-layer resist film, and then the upper layer resist is formed. After forming a resist pattern on the upper layer by exposing and drawing, and then developing, the lower organic polymer film is etched with oxygen plasma using the upper resist pattern as a retention mask to form a resist pattern on the substrate to be processed. In the forming method, the photosensitive resist has an aromatic ring, and part or all of the aromatic ring has the formula: -
OH2N! A method for forming a fine pattern, comprising using a photosensitive resin composition containing a silicone-containing resin having a substituent represented by the following.