JPS61260238A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To prevent effect of light reflected from a support and swelling of a photohardened product due to a developing soln., and to enhance resolution, dry etching and heat resistances by incorporating a polymer soluble in an aq. alkaline soln., a siloxane ladder polymer, and an aromatic azido compound. CONSTITUTION:The photosensitive compsn. contains a polymer soluble in an aq. alkaline soln., such as a novolak resin, a hydroxystyrene polymer, or poly(meth)acrylic acid, in the form of a homocondensate, cocondensate, homopolymer, or copolymer; a siloxane ladder polymer; and an aromatic azido compound, thus permitting the obtained photosensitive compsn. to be unaffected by the light reflected from the support, to be formed into a rectangular micropattern because this photohardened product is not swelled with a developing soln., and to be subjected to dry etching treatment after formation of the pattern, without trouble, such as exhaustion of a resist before completion of perfect etching of the layer to be treated, or thinning of pattern width, and to resist heat treatment even >=150 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photosensitive composition, and more particularly to a photosensitive composition suitable for manufacturing semiconductor devices and having high dry etching resistance and high heat resistance.

(Prior art) In order to improve the performance of semiconductor devices such as IC1ISI,
It is necessary to improve the fineness of the processing, and for this purpose dry etching processing is used. The photosensitive resist used in this dry etching process is required to have particularly high dry etching resistance and heat resistance.

The most commonly used photoresists for manufacturing semiconductor devices are positive photoresists, which are made by mixing alkali-soluble phenolic resin with a naphthoquinonediazide derivative as a photosensitive component, and negative photoresists, which are made by mixing cyclized rubber with aromatic bisazide as a photosensitive component. type photoresist.

However, when performing microfabrication of semiconductor materials such as AllAlIl alloy, SiO There were problems in that the pattern became thin and the area around the pattern became hollow.

To solve these problems, various silicon-based resists have been proposed (for example, Japanese Journal of Applied Physics).
se Journal.

f Applied physics), Volume 22 (
10), p. 659 (1983), Journal of the Electrochemical Society (Journa
l of the electr.

Chemical 5ociety), 130 volumes.

1962-1964 pages (1983), JP-A-57-16
No. 8247, Japanese Unexamined Patent Publication No. 168246/1982).

However, all of these silicon-based resists are resist materials for lithography using electron beams, X-rays, ion beams, etc., and cannot be used in general-purpose lithography using ultraviolet rays.

As a silicon-based resist sensitive to ultraviolet rays, a photosensitive composition containing polyladder siloxane y and an aromatic azide compound has been proposed (Japanese Patent Laid-Open No. 58-9665).
No. 4), this has the disadvantage that cranks are likely to occur during pattern formation.

Furthermore, a resist with excellent dry etching resistance is also known, which is made by adding polyladder siloxane to a positive resist using an alkaline aqueous solution-soluble polymer (Polymer Engineering and Science).
Engineer'ring and 5cien
ce) Volt, 20° 1087 pages (1980)).

However, since this resist also has a high light transmittance, it is easily affected by reflected light from the substrate, resulting in the pattern width becoming narrow or rectangular, and the pattern size of the processed layer being etched. It has the disadvantage that it is often thinner than the predetermined size.

(Problems to be Solved by the Invention) An object of the present invention is to eliminate the drawbacks of the prior art, so that the photocured material is not affected by reflected light from the substrate and does not swell with the developer. Therefore, it is an object of the present invention to provide a photosensitive composition that provides high resolution and has excellent dry etching resistance and heat resistance.

(Means for Solving the Problems) As a result of various studies, the present inventors have found that a photosensitive composition combining an alkaline aqueous solution soluble polymer, a polyladder siloxane, and an aromatic azide compound achieves the above object. They discovered this and arrived at the present invention.

The present invention relates to a photosensitive composition containing an alkaline aqueous solution-soluble polymer, a polyladder siloxane, and an aromatic azide compound.

The alkaline aqueous solution-soluble polymer used in the photosensitive composition of the present invention is photochemically cured with an aromatic azide compound used as a photosensitive compound in the present invention,
It is a compound that can be insolubilized in an aqueous alkaline solution and has a hydroxyl group or a carboxyl group. Examples of alkaline aqueous solution-soluble polymers include novolac resins, hydroxystyrene polymers, acrylic acid or methacrylic acid polymers, etc., which may be used in the form of homocondensates, cocondensates, homopolymers or copolymers. used.

Further, these may be used alone or in a mixture of two or more.

The alkaline aqueous solution-soluble polymer is preferably a novolak resin, a hydroxystyrene polymer, a polymer of acrylic acid or methacrylic acid, or a combination of two or more thereof.

These polymers are also available commercially.
For example, novolak resins include phenol novolak resin, cresol novolak resin, phenol cresol novolak resin, and the like. In addition, as a hydroxystyrene polymer, poly(P-vinylphenol)
, brominated poly(p-vinylphenol), etc. As a polymer of acrylic acid or methacrylic acid,
Examples include acrylic acid or methacrylic acid polymers, copolymers of acrylic acid or methacrylic acid and acrylic esters or methacrylic esters, copolymers of acrylic acid or methacrylic acid and styrene, and the like.

The alkaline aqueous solution-soluble polymer used in the present invention is heated at a temperature of 10 to
It is necessary to be able to form a film at 100°C, and for this purpose, the number average molecular weight is preferably 500 or more. Furthermore, considering the heat resistance as a photosensitive composition, the number average molecular weight of the alkaline aqueous solution-soluble polymer is preferably 1000 or more. The polyladder siloxane used in the present invention is a known compound (Japanese Patent Publication No. 40-15989)・U,
S, P, 3017386, etc.), for example, a compound represented by formula CI).

(In the formula, R1 and R2 mean an optionally substituted aliphatic or aromatic hydrocarbon residue, and n means a positive integer.) In the formula (I), R1 and R2 are, for example, a methyl group. ,
Examples include aliphatic hydrocarbon residues such as alkyl groups such as ethyl groups and propyl groups, aromatic hydrocarbon residues such as phenyl groups and substituted phenyl groups, and halogen-substituted products of these, but the heat resistance after photoreaction An aromatic hydrocarbon residue is preferable in order to increase the

Further, in the above formula (I), n is a positive integer, but an integer larger than 50 is usually preferable.

The aromatic azide compound used as a photosensitive compound in the photosensitive composition of the present invention generates an active species nitrene upon irradiation with light, and this active species undergoes dimerization, addition to double bonds,
A hydrogen abstraction reaction or the like is caused to cause a difference in solubility in a developer between the light-irradiated area and the non-light-irradiated area of the coating film obtained by applying the photosensitive composition of the present invention, thereby forming a pattern.

Examples of the aromatic azide compound used in the present invention include compounds represented by formula (n), (III) or (IV).

or S2; (meaning a positive integer smaller than) formula (II
), for example, 4
, 4w-diazidophenyl sulfide, 4.4''-diazidophenyl sulfone, 3゜31-diazidophenyl sulfone, 4.4''-diazidiphenylmethane, 3.3
'-dichloro-ichiban, 4'-diazidiphenylmethane,
Examples thereof include 4,41-diazidophenyl ether, 4,4t-diazidophenyldisulphy)', and 4.4''-diazitobibenzyl.

R3 in the above formula) is an alkyl group preferably having 5 or less carbon atoms such as a methyl group or an ethyl group, an alkoxy group preferably having 5 or less carbon atoms such as a methoxy group or an ethoxy group, -CH2C
It means a hydroxyalkyl group preferably having 5 or less carbon atoms, such as H20H, or an aminoalkyl group, preferably an aminoalkyl group whose alkyl group has 5 or less carbon atoms.

Examples of the aromatic azide compound represented by formula (III) include 4'-azidobenzal-4-methylacetophenone, 3''-azidobenzal-4-hydroxyacetophenone, 41-azidobenzal-3-ethoxyacetophenone, 41-azidobenzal-4- Ethoxyacetophenone, 31-azidobenzal-4-(N,N-dimethylamino)ethyl acetophenone, 4t-azidobenzal-2-methoxyacetophenone, 41-azidobenzal-2-ethoxyacetophenone, and the like.

As the aromatic azide compound represented by formula (IV),
3-(4”-azidostyryl)-5,5-dimethyl-2
-cyclohexen-1-one, 3-(4''-azidophenyl-1', 3'-butadienyl)-5,5-dimethyl-2-cyclohexen-1-one, and the like.

The photosensitive composition of the present invention comprises an alkaline aqueous solution-soluble polymer,
A polyladder siloxane and an aromatic azide compound are mixed in an appropriate proportion using an appropriate organic solvent and used as a solution.

The organic solvent used at this time is preferably one that can dissolve any of the alkaline aqueous solution-soluble polymer, polyladder siloxane, and aromatic azide compound, such as ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Solvents such as cellosolve solvents such as methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate and ethyl cellosolve acetate, and ester solvents such as ethyl acetate, butyl acetate and isoamyl acetate are used. These may be used alone or in combination of two or more. The blending ratio of these organic solvents is preferably in the range of 100 to 1000 parts by weight based on 100 M parts of the alkaline aqueous solution-soluble polymer, polyladder siloxane, and aromatic azide compound.

In the photosensitive composition of the present invention, the blending ratio of the aromatic azide compound is preferably 5 to 100 parts by weight, particularly preferably 5 to 50 parts by weight, based on 100 parts by weight of the alkali aqueous solution-soluble polymer. If the proportion of the aromatic azide compound is too high, the aromatic azide compound may precipitate during storage,
The heat resistance after the photoreaction decreases, and if this ratio is too small, the difference in solubility in a developer between the light irradiated area and the unexposed area becomes small after the photoreaction, resulting in a decrease in pattern forming ability.

The blending ratio of polyladder siloxane is 0.1 to 100 parts by weight per 100 parts by weight of the alkali aqueous solution-soluble polymer.
Parts by weight are preferred, and 1 to 50 parts by weight are particularly preferred. If the blending ratio of polyladder siloxane is too high, cracks will occur during pattern formation, and if this ratio is too low, dry etching resistance will be reduced.

The photosensitive composition of the present invention may further contain secondary components as necessary, such as a thermal polymerization inhibitor for storage stability, an antihalation agent for preventing halation from the substrate, and an improved adhesion to the substrate. Adhesion improvers, dyes, pigments, fillers, flame retardants, sensitizers, etc. can be contained.

After applying the photosensitive composition of the present invention in the above-mentioned solution state to a substrate by an appropriate method, the solvent is dried and light irradiation is performed,
Thereafter, the non-irradiated areas are removed with a developer to form a resist pattern.

As the developer, for example, an aqueous solution of a tetraalkylammonium hydroxide such as tetramethylammonium hydroxide, an aqueous inorganic alkali solution such as potassium hydroxide, tertiary sodium phosphate, sodium hydroxide, etc. are used. These developers are usually used at a concentration of 5% by weight or less.

(Effects of the Invention) The photosensitive composition of the present invention is not affected by light reflected from the substrate after photoreaction, and its photocured product does not swell in a developer, so it can form fine rectangular patterns. can be formed. In addition, it has excellent dry etch resistance and heat resistance, so even if dry etch lag treatment is performed after pattern formation, the resist will run out or the pattern width will become narrower before the processed layer is completely etched. Moreover, it can withstand heat treatment at 150°C or higher. The photosensitive composition of the present invention can be suitably used when performing dry etching, which is essential for microfabrication, after pattern formation using an ultraviolet exposure device commonly used in semiconductor device production.

(Example) Parts in the following examples mean parts by weight.

Example 1 10 parts of Talesol Novolank resin was dissolved in 120 parts of ethyl cellosolve acetate, and further 2 parts of 41-azidobenzal-2-ethoxyacetophenone and polyladder siloxane (GR-100 manufactured by Showa Denko K.K., the above formula (
A solution of the photosensitive composition of the present invention was prepared by melting 0.5 part of the compound I) in which R1 and R2 were methyl groups and phenyl groups in a ratio of 2:1.

This solution was spin-coated using a spinner onto a substrate having a polyimide resin formed on an aluminum layer as a processed layer, and then dried at 80° C. for 20 minutes to obtain a coating film with a thickness of 0.8 μm.

This coating film was irradiated with ultraviolet rays for 5 seconds through a quartz mask from a distance of 30a1 using a 250WOHg lamp. Next, spray development was carried out using a 0.15N aqueous solution of potassium hydroxide, and further washing was performed with water to obtain a good resist pattern.

Then put it into a plasma reactor device and set the oxygen flow rate to 10
0m#/min, high frequency output 350W, applied frequency 13
．． Oxygen plasma etching for 2 minutes under the condition of 56 MH2 resulted in a pattern in the polyimide layer that was the same as the resist pattern. At this time, no change was observed in the size of the resist pattern.

Example 2 10 parts of poly(P-vinylphenol), 3 parts of 4g-azidobenzal-4-hydroxyacetophenone, and polyladder siloxane (GR-15 manufactured by Showa Denko K.K.)
0, R1 and R2 of the above formula (1) are methyl group and phenyl group, the ratio is 1:1) 1 part is dissolved in ethyl cellosolve acetate 120H to prepare a solution of the photosensitive composition of the present invention. did.

This solution was spin-coated using a spinner onto a substrate having a polyimide resin formed on an aluminum layer as a processed layer, and then dried at 70° C. for 20 minutes to obtain a coating film with a thickness of 1 μm. This coating film was irradiated with ultraviolet rays for 5 seconds under the same conditions as in Example 1, developed using a 0.1N aqueous solution of tetramethylammonium hydroxide, and further washed with water to obtain a good resist pattern. .

The sample was then placed in a plasma reactor and subjected to oxygen plasma etching for 2 minutes under the same conditions as in Example 1 to obtain the same pattern as the resist pattern on the polyimide layer. At this time, no change was observed in the size of the resist pattern.

Example 3 Phenol m-cresol copolymerization type novolac resin 20
4 parts, 4 parts of 41-diazidophenyldisulfide and polyladder siloxane (GR-1 manufactured by Showa Denko K.K.)
00) 2 parts of methyl cello/L/7" acetate 80
A solution of the photosensitive composition of the present invention was prepared by dissolving the photosensitive composition in 1 part.

This solution was spin-coated using a spinner onto a substrate having a polyimide resin formed on an aluminum layer as a processed layer, and then dried at 70° C. for 20 minutes to obtain a coating film with a thickness of 0.9 μm.

This coating film was exposed to light using a lkw Xe-Hg lamp through a quartz mask. The light intensity at a wavelength of 254 nm is 5.
The exposure time was 5 mW/d and 2 seconds. Next, it was developed using a 0.1N aqueous solution of tetramethylammonium hydroxide and further washed with water to obtain a good resist pattern.

The sample was then placed in a plasma reactor and subjected to oxygen plasma etching for 2 minutes under the same conditions as in Example 1 to obtain the same pattern as the resist pattern on the polyimide layer. At this time, no change was observed in the size of the resist pattern.

Example 4 20 parts of poly(P-vinylphenol), 4 parts of 3-(41-azidostyryl)-5,5-dimethyl-2-cyclohexen-1-one, and polyladder siloxane (GR-100 manufactured by Showa Denko K.K.) ) was dissolved in 80 parts of cyclohexanone to prepare a solution of the photosensitive composition of the present invention.

This R liquid was spin-coated onto a silicon wafer using a spinner, and then dried at 80° C. for 20 minutes to obtain a coating film with a thickness of 1 μm. This coating film was irradiated with ultraviolet rays for 5 seconds under the same conditions as in Example 1, and then washed with 7JIrJR using a 0.1N aqueous solution of tetramethylammonium hydroxide and further washed with water to obtain a good resist pattern. .

No change was observed in this pattern even after heating at 170° C. for 30 minutes.

Comparative Example 1 Negative photoresist (trade name RU-100ON) consisting of an alkaline aqueous solution soluble polymer and an aromatic azide compound
(manufactured by Hitachi Chemical Co., Ltd.), a coating film is formed on the polyimide resin layer in the same manner as in Example 1, and oxygen plasma etching is performed. When a resist pattern similarly formed on a silicon wafer was heat-treated with 15 l, pattern flow occurred.

Comparative Example 2 Polyladder siloxane (trade name: GR-
100 (manufactured by Showa Denko KK) was added in the same manner as in Example 4 to prepare a solution by adding 4 parts of the resin.

This solution was applied with a spinner onto a substrate with a polyimide resin formed on an aluminum layer as a processed layer, and then
It was dried at ℃ for 20 minutes to obtain a coating film with a thickness of 1 μm. This coating film was irradiated with ultraviolet rays for 5 seconds through a quartz mask under the same conditions as in Example 1, and then developed using a dedicated developer NMD-3 (manufactured by Schiffbray) to obtain a resist pattern.

Claims (1)

[Scope of Claims] 1. A photosensitive composition containing an alkaline aqueous solution-soluble polymer, a polyladder siloxane, and an aromatic azide compound. 2. The alkaline aqueous solution soluble polymer is a novolac resin,
The photosensitive composition according to claim 1, which is at least one polymeric compound selected from the group consisting of a hydroxystyrene polymer and a polymer of acrylic acid or methacrylic acid.