JPH03260653A - Pattern forming method and photosensitive resin composition - Google Patents

Abstract

PURPOSE:To simplify a process for forming a resist pattern by irradiating a film made of the composition containing a specified polymer with light and heating it after development. CONSTITUTION:This photosensitive resin composition contains the polymer (A) having structural units represented by the formula; -(RMO1.5)- in which R is an organic group, and M is a metal atom. The film made of this composi tion is formed on a substrate, prebaked, imagewise exposed, developed, and then, heated together with the substrate to decompose a part of the organic materials or all of them in the composition and to form a pattern made of metal oxides or the like. The polymer A can be embodied by a polymer obtained by introducing acetyl chloride into polymethylsilsesquioxane, and the like and the film of the composition can be formed by using a solution containing the polymer and a photosensitive agent, such as o- naphthoquinonediazide.

Description

[Detailed Description of the Invention] [Industrial Application Field] The first invention of the present invention relates to a pattern forming method applicable to various surface protection films, insulating films, optical waveguide films, etc.; The invention relates to a photosensitive resin composition that can be applied to such a pattern forming method and can also be used as a positive resist with excellent resistance to oxygen plasma (02RIB).

[Conventional technology]

Conventionally, when forming a pattern made of oxide on a substrate, first, a glass fine particle layer having a predetermined thickness is deposited on the substrate, and then a sintered layer is formed by heating the glass fine particle layer. Next, a resist material is applied onto the sintered oxide layer, a resist pattern is formed by lithography, and unnecessary oxide is removed by etching.

[Problem to be solved by the invention]

These conventional methods require extremely strict process control in order to create a uniform film, and also involve a large number of steps to form a pattern, which poses problems in terms of productivity and economy. Ta.

A first object of the present invention is to significantly simplify the conventional pattern forming process.

A second object of the present invention is to provide a photosensitive resin composition that can be applied to the first aspect of the invention and can be used as a positive resist material.

[Failure to solve the problem]

To summarize the present invention, the first invention of the present invention is a starting point regarding a pattern forming method, and is a polymer containing a chemical structure represented by the general formula +RMO, . The method is characterized in that a film of a photosensitive resin composition containing (M represents a metal) is irradiated with light to form a pattern and then heated.

The second invention of the present invention relates to a photosensitive resin composition, which comprises a metal alkoxide hydrolysis/condensation product containing at least one component of a metal alkoxide having a carboxylic acid group or a carboxylic acid anhydride group. It is characterized by containing an orthonaphthoquinone compound.

In other words, the photosensitive resin composition used in the present invention undergoes structural changes such as crosslinking, decomposition, and isomerization when exposed to light, and therefore, like ordinary photoresists, a negative or positive pattern can be formed upon exposure. be done. General formula +RMO,, + contained in such a photosensitive resin composition
Polymers containing the chemical structure represented by the following are characterized by having at least a partially ladder-like structure and a higher content of M-0 bonds than ordinary organic polymers having a ladder structure. Therefore, when a pattern of the composition is heated, some or all of the organic groups are removed, thereby forming a pattern of an oxide or an oxide analog having a chemical structure similar to an oxide.

General formula +RMO, contained in the photosensitive resin composition used in the first invention of the present invention. The organic group represented by R in the polymer containing the chemical structure represented by 5+ is not particularly limited, but includes alkyl groups such as methyl, ethyl, propyl, butyl, alkenyl groups such as vinyl group, isopropenyl group, etc. aryl groups such as phenyl, alkenoyl groups such as acryloyl and methacryloyl groups, and derivatives thereof. Further, the metal represented by M in the polymer containing the chemical structure represented by the general formula +RMO,,s+ used in the present invention is not particularly limited, but may include Sl, Ge, Ti, Zr, ^1, B,
Z5 Nb, Ga, Sn, Pb, Sb, Ta5
Examples include Nd and Br.

There are no particular limitations on the method for producing the polymer containing the chemical structure represented by the general formula -Hn1o, . It can be obtained by hydrolyzing and condensing substances or by deriving hydrolyzed and condensed products.

By using a trifunctional metal alkoxide or metal chloride as at least one component of the above metal alkoxide or metal chloride as a starting material, a polymer containing a ladder-shaped structure having the above general formula can be obtained. Examples of this type of metal alkoxide include the following.

Methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, Butyltriethoxysilane, hexyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, 4-trimethoxysilyltetrahydrophthalic anhydride, 3.3. 3-) Lifluoropropyltrimethoxysilane, 3-(N-methylamino)propyltrimethoxysilane, methyltris(2aminoethoxy)silane, 2-mercaptoethyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane Methoxysilane, 2-cyanoethyltriethoxysilane, allyl) IJ ethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, methyltripropoxysilane, 3
-[N-Original N(2-γminoethyl)17minobrobyltrimethoxysilane, 3-(N-allyl-N-glycidyl)aminopropyltrimethoxysilane, 3-(N
N-diglycidyl)aminopropyltrimethoxysilane, methyltrimethoxygermane, ethyltrimethoxygermane, propyltrimethoxygermane, butyltrimethoxygermane, hexyltrimethoxygermane, vinyltrimethoxygermane, phenyltrimethoxygermane, methyltriethoxygermane, Ethyltriethoxygermane, propyltriethoxygermane, butyltriethoxygermane, hexyltriethoxygermane, vinyltriethoxygermane, phenyltriethoxygermane, methyltrimethoxytitanium, ethyltrimethoxytitanium, propyltrimethoxytitanium, butyltrimethoxytitanium, Hexyltrimethoxytitanium, vinyltrimethoxytitanium, phenyltrimethoxytitanium, methyltriethoxytitanium, ethyltriethoxytitanium, propyltriethoxytitanium, butyltriethoxytitanium,
Hexyltriethoxytitanium, vinyltriethoxytitanium, phenyltriethoxytitanium, methyltrimethoxyzircone, dithyltrimethoxyzircone, phenyltrimethoxyzircone, methyltriethoxyzircone, ethyltriethoxyzircone, phenyltriethoxyzircone, methyltributoxyzircone , ethyltributoxyzircon, phenyltributoxyzircone, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, tetraethoxyzircon, tetrabutoxyzircon, tetraisopropoxyzircon, tetramethoxygermane, tetraethoxytitanium, tetrabutoxytitanium, tetrabutoxy Tin, pentabutoxy niobium, pentabutoxy thalium, triethoxy boron, tributoxy gallium, dibutoxy ship, tributoxy neodymium, tributoxy erbium, dimethyljethoxysilane, diphenyljethoxysilane.

In addition, examples of metal chlorides include n-butyl)IJ chlorosilane, ethyltrichlorosilane, methyltrichlorosilane, phenyltrichlorosilane, methyltrichlorogermane, methyltrichlorotitanium, tetrachlorosilane,
Tetrachlorogermane, tetrachlorotitanium, tetrachlorosilane, tetrachlorogermane, tetrachlorotitanium, tetrachlorozircone, dimethyldichlorosilane,
Examples include diphenyldichlorosilane.

The photosensitizer used in the first invention is not particularly limited, and examples include photosensitizers commonly used in the field of photoresists, such as aromatic bisazides, naphthoquinone azides, and diazomeldrum's acid.

Next, an example of the pattern forming method according to the first invention will be described. First, a film of the photosensitive resin composition of the present invention is formed on a substrate such as silicon by a spin code, then prebaked, and then irradiated with light to make only the irradiated area soluble in a developing solvent, and then developed to make the irradiated area soluble. The photosensitive resin composition is removed and a pattern of the photosensitive resin composition is formed. Next, the substrate is heated to decompose part or all of the organic matter in the photosensitive resin composition constituting the pattern, forming a pattern of oxide or oxide analog.

This example uses a positive photosensitive resin composition, but if a negative photosensitive resin composition is used, only the light irradiated area becomes insoluble in the developing solvent and a negative pattern can be obtained. Not even.

In the present invention, pattern dimensions can be controlled by the composition of the photosensitive resin composition, polymer structure, film thickness, heating temperature, etc. The larger the molecular weight of the organic group (R) in the polymer, the thinner the finished pattern film thickness becomes.
In the temperature range of 0 to 700°C, the film thickness tends to become thinner when heated at a higher temperature. Further, the film thickness can also be changed depending on the polymer concentration, additive concentration, etc. in the composition.

Now, the second invention of the present invention relates to a particularly useful photosensitive resin composition among photosensitive resin compositions containing a polymer obtained by hydrolysis/condensation of the metal alkoxide. These photosensitive resin compositions contain at least a polymer obtained by hydrolysis and condensation of a metal alkoxide having at least one component a metal alkoxide having a carboxylic acid group or a carboxylic acid anhydride group, and an orthonaphthoquinone compound. .

The polyfunctional metal alkoxide having a carboxylic acid group or carboxylic acid anhydride group used in the second invention is not particularly limited; There are functional alkoxysilanes.

Specifically, 4-trimethoxysilyltetrahydrophthalic anhydride, 4-triethoxysilyltetrahydrophthalic anhydride, 4-triisopropoxysilyltetrahydrophthalic anhydride, 4-trimethoxysilyltetrahydrophthalic acid, 4- Examples include triethoxysilyltetrahydrophthalic acid and 4-triisopropoxysilyltetrahydrophthalic acid. Further, the metal alkoxide is not particularly limited, and may include Sl and Ge.

T1, Zr, ^1, B, 2r, Nb5Ga, 5n
Examples include alkoxides such as SPb, Sb, Ta, Nd, and Br. Among these, particularly preferred are:
Tetraalkoxysilane, tetraalkoxytitanium, tetraalkoxygermane, tetraalkoxyzircone, and substituted metal alkoxides in which one or two of the alkoxyl groups in these alkoxides are substituted with organic groups.

The orthonaphthoquinone-based photosensitizer in the second invention is not particularly limited, but refers to a photosensitizer containing orthonaphthoquinone azide (1) in the compound. Generally, orthonaphthoquinone azide is bonded to the hydroxyl group of a polyhydric phenol in the form of a sulfonic acid ester.

Polymers obtained from the above alkoxides have carboxylic acid groups and are soluble in alkali, which is the developing solvent for ordinary photoresists, and when tetraalkoxysilane is used as the other alkoxide component, It is characterized by a higher silicon content than normal photoresists. Therefore, the photosensitive resin composition of the second invention in which an orthonaphthoquinone-based photosensitizer is added to the polymer is 02R.
It can be used as a positive photoresist with excellent IB resistance. That is, the photosensitive resin of the present invention
Upon irradiation, the orthonaphthoquinone compound in the irradiated area turns into the corresponding indenecarboxylic acid, and the irradiated area is removed by alkaline development, thus exhibiting positive resist characteristics.

In addition, a negative pattern can be formed using an image reversal method in which the entire surface is irradiated with ultraviolet rays and then exposed after pattern exposure with high-energy rays.

Another use of the photosensitive resin composition of the second invention is the pattern forming method of the first invention. In this case, after forming a pattern of the photosensitive resin composition on the substrate, heating is performed to cause condensation between reactive groups such as silanol groups contained in the photosensitive resin composition, and also to cause condensation of reactive groups such as silanol groups contained in the photosensitive resin composition. By removing part or all of the oxide, a strong oxide or oxide analog pattern with excellent optical transparency is formed.

〔Example〕

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

Example 1 4-trimethoxysilyltetrahydrophthalic anhydride 0
．． 2 moles of phenyltriethoxysilane, 0.4 moles of phenyltriethoxysilane, and 0.4 moles of htetraethoxysilane.
A photosensitive resin composition was prepared. Next, a photosensitive resin composition is applied to a silicon wafer to a thickness of about 1.2 μm,
Prebaked at 80°C for 20 minutes. After prebaking, ultraviolet rays were irradiated using a mask aligner (manufactured by Canon).

After irradiation, Microposit 2401 (manufactured by Sibley)
The film was developed with a developer having a ratio of 1/1 to water, and the sensitivity was determined as the irradiation dose at which the remaining film in the irradiated area was 50% of the initial film thickness. In addition, resolution was determined by measuring the minimum pattern size that can be resolved in a line & space pattern. The sensitivity and minimum pattern size were 30 mJ/cm2.0.5 μm, respectively.

Example 2 4-trimethoxysilyltetrahydrophthalic anhydride 0
．． A photosensitive resin composition was prepared by dissolving in MIBK a polymer which is a hydrolysis/condensation product of 2 moles of methyltriethoxysilane, 0.4 moles of methyltriethoxysilane, and 0.4 moles of htetraethoxysilane, and a novolac-based orthonaphthoquinone azide as a photosensitizer. And so. Next, the photosensitive resin composition was applied to a silicon wafer to a thickness of about 1.2 μm, and prebaked at 80° C. for 20 minutes. After prebaking, the mask was irradiated with ultraviolet light using a mask T-liner (manufactured by Canon), and then developed with an alkaline aqueous solution to obtain a corresponding pattern. The sensitivity and minimum pattern size evaluated by the same method as in Example 1 were 30 J/C [
I+2.0.5 μm.

Next, the silicon wafer with the pattern was heated at 900°C for 3
A transparent pattern was obtained by heating for a period of time. When the infrared spectrum of the obtained pattern was measured, it was found that the absorption of C=0 of the polymer in the vicinity of 170 (1 to 1750 cm), 1200 and 780 ct was observed before heating.
Absorption of 5i-CH of n-', 1710 cm of photosensitizer
-'(COO) absorption almost disappeared, 1100.8
Absorption of 81-0 was observed at 00 and 470 cl'.

Example 3 Polymethylsilsesquioxane, which is a hydrolysis/condensation product of methyltriethoxysilane, was reacted with acetyl chloride using aluminum chloride as a catalyst to obtain a polymer having acetyl groups and silanol groups introduced therein. This polymer and novolak-based orthonaphthoquinone azide were dissolved in ethyl cellosolve to prepare a photosensitive resin composition. This photosensitive resin composition was applied to a substrate by dip coating and then air-dried to form an organic film. Figure 1 shows the results of thermogravimetric analysis (heating rate 20°C/min) of this precursor in air.
It is a diagram showing the relationship between the horizontal axis) and the weight remaining rate (%, vertical axis). Following weight loss due to condensation around 200°C
At around 400°C, weight loss due to elimination of organic groups is observed. The weight loss rate at 600° C. is about 20%, and almost no weight change is observed above this temperature.

Next, this precursor film was heated at a temperature of 400° C. to 900° C. for 3 hours each. A transparent and uniform film was formed at any temperature. Figure 2 shows heat treatment humidity (°C, horizontal axis) and film thickness (
FIG. The film thickness is almost constant at around 700°C.

Figure 3 shows the infrared spectrum of the film heat-treated at 700℃.
It is a diagram showing the relationship between wave number (cm-', horizontal axis) and transmittance (vertical axis). By heat treatment at 700℃,
The absorption of 5l-CH3 near 1200c+n-' and 780cm-', which was observed in the photosensitive resin composition, almost disappeared, and the
Absorption of 81-0 near 0 Ca1l-' is observed.

Note that the absorption near 600 crn-' is the absorption of the silicon substrate.

Furthermore, it was observed that the films produced at any heat treatment temperature were insoluble in general-purpose organic solvents and had excellent chemical resistance.

Based on the above findings, a pattern of the above photosensitive resin composition was formed on a quartz glass substrate and then heated at 700°C to form a pattern with a width of 0.5 μm and a pitch interval of 1.0 μ0.

Example 4 Phenylpolysilsesquioxane, which is a hydrolysis/condensation product of phenyltriethoxysilane, was reacted with acetyl chloride using aluminum chloride as a catalyst to obtain a polymer having acetyl groups and silanol groups introduced therein. This polymer and novolak-based orthonaphthoquinone azide were dissolved in ethyl cellosolve to prepare a photosensitive resin composition.

This solution was applied to a silicon substrate and a quartz glass substrate using a spin cord to form a precursor film with a thickness of about 2.5 μm. Next, after air-drying these films, they were heated for 400 min in an electric furnace.
Heat treatment was performed at temperatures ranging from .degree. C. to 900.degree. C. for 1 hour, respectively. A uniform, crack-free film was formed at any temperature.

Figure 4 shows the film (No. 41) before heat treatment applied to the silicon substrate.
1! IA) and the film heat-treated at 900°C for 1 hour (Figure 4B) are shown in the wave number (COT-', horizontal axis).
FIG. 10 is a diagram showing the relationship between and transmittance (vertical axis). Almost no absorption by the photosensitizer or polymer is observed in the spectrum after heat treatment.

Figure 5 shows the transmission characteristics before heat treatment (Figure 5, ■) and after heat treatment at 900°C (Figure 5, j) in terms of the relationship between wavelength (nff1, horizontal axis) and transmittance (%, vertical axis). This is a diagram.

In the spectrum after heat treatment, no absorption of phenyl groups observed at 0.2 to 0.3 μm was observed, indicating excellent light transmittance over a wide wavelength range.

Based on the above findings, a pattern of the above photosensitive resin composition was formed on a quartz glass substrate, and then heated at 900°C to form a pattern with a width of 0.5 μm and a pitch interval of 1.0 μm.

Example 5 Phenylpolysilsesquioxane having a carboxyl group, which is a hydrolysis/condensation product of 0.8 mol of phenyltriethoxysilane and 0.2 mol of 4trimethoxysilyltetrahydrophthalic anhydride, and novolac-based orthonaphthoquinone Azide was dissolved in MIBK to prepare a photosensitive resin composition. Next, a film of the photosensitive resin was formed on a quartz glass substrate, exposed to light through a photomask, and developed with an alkaline solution to form a pattern of the photosensitive resin. Furthermore, by heating the substrate at 900°C for 2 hours, the width is 0,
A pattern of 5 μm and a pitch interval of 1.0 μm was formed.

Example 6 4-trimethoxysilyltetrahydrophthalic anhydride 0
．． A photosensitive resin composition was prepared by dissolving a hydrolysis/condensation product of 3 moles of tetraethoxysilane and 0.7 moles of tetraethoxysilane and novolac-based orthonaphthoquinone azide in MIBK. next,
After forming a film of the photosensitive resin on a silicon wafer, it was exposed to light through a photomask and developed with an alkaline solution to form a pattern of the photosensitive resin. Furthermore, the substrate is 120
By heating at 0°C for 2 hours, the width of 0.5 μm per pitch is 11*1. A pattern of 0 μm was formed.

Example 7 4-trimethoxysilyltetrahydrophthalic anhydride 0
．． 2 moles of methyltriethoxysilane, 0.7 moles of methyltriethoxysilane, 0.1 moles of methyltributoxytitanium, and novolac-based orthonaphthoquinone azide in MIB.
It was dissolved in K to obtain a photosensitive resin composition. Next, a film of the photosensitive resin was formed on a silicon wafer, exposed to light through a photomask, and developed with an alkaline solution to form a pattern of the photosensitive resin. Further, by heating the substrate at 1200° C. for 2 hours, the width is 0.5 μm and the pitch interval is 1.
A pattern of 0μ mountains was formed.

Example 8 A hydrolysis/condensation product of 0.6 mol of methyltriethoxysilane and 0.6 mol of 3-methacryloyloxypropyltrimethoxysilane and a trihydroxybenzophenone-based photosensitizer were dissolved in MIBK to form a photosensitive resin composition. did.

Next, a film of the photosensitive resin was formed on a silicon wafer, exposed to light through a photomask, and the unexposed portions were removed to form a pattern of the photosensitive resin. Furthermore, 10 pieces of the substrate
By heating at 00° C. for 2 hours, a pattern with a width of 0.6 μm and a pitch interval of 1.2 μm was formed.

〔Effect of the invention〕

As explained above, the present invention uses a photosensitive resin composition that becomes an oxide or an oxide analog when heated, forms a pattern by irradiation with light, and then forms an oxide or an oxide analog by heating. This method has the advantage that the process can be significantly simplified compared to conventional oxide pattern forming methods. Therefore, there is a possibility that it can be used for forming optical waveguides and forming guide grooves and pit patterns on optical disk substrates.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the results of thermogravimetric analysis in air of the precursor produced in Example 3, FIG. 2 is a diagram showing the relationship between heat treatment temperature and film thickness of the precursor produced in Example 3, FIG. 3 is a diagram showing the infrared spectrum of the film produced in Example 3 and heat-treated at 700°C. FIG. 4 is a diagram showing the infrared spectrum of the film produced in Example 4 before and after heat treatment. The figure is a diagram showing the permeation characteristics of the membrane produced in Example 4.

Claims (1)

[Claims] 1. A polymer having a chemical structure represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (where R is an organic group and M is a metal)
A method for forming a pattern, which comprises irradiating a film of a photosensitive resin composition containing the above with light to form a pattern, and then heating the film. 2. A photosensitive resin composition containing an orthonaphthoquinone compound and a metal alkoxide hydrolysis/condensation product containing at least one component of a metal alkoxide having a carboxylic acid group or a carboxylic acid anhydride group.