JPH02130552A - Pattern forming material - Google Patents

Abstract

PURPOSE:To obtain the pattern forming material which is particularly adequate for a resist process of a two-layered structure exhibiting resistance to RIE (reactive ion etching) of oxygen by incorporating an alkaline soluble phenolic resin having a specific structural unit and diazocarbonyl compd. into the above- mentioned material. CONSTITUTION:This pattern forming material contains the alkaline soluble phenolic resin having the specific structural unit expressed by formula I and the diazocarbonyl compd. In the formula, R<1>, R<2> are the same or different and are as expressed by formula II. In formula II, n=1 to 5; R<3> to R<5> may be the same or different and are a lower alkyl group or as expressed by the formula III. In formula III, R<6> to R<8> are the same or different and a lower alkyl group or phenyl group. The pattern forming material adequate as the resist for upper layers having the excellent resistance to RIE of oxygen is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pattern forming material, and more particularly to a fine pattern forming material necessary for manufacturing semiconductor devices, magnetic bubble memory devices, integrated circuits, etc. .

(Prior Art) Photolithography is used as an important means in manufacturing semiconductor devices, magnetic bubble memory devices, and the like. In photolithography, light diffraction,
It is known that resolution decreases when the resist film is thick due to effects such as reflection from the substrate. Therefore, if the thickness of the resist is reduced in order to obtain a high-resolution pattern, there is a problem that the resistance of the resist becomes insufficient in subsequent steps. Furthermore, the substrate surface processed by photolithography is not necessarily flat;
Since the film often has various uneven steps, a sufficient film thickness is required to cover these steps.

It is difficult to satisfy these conflicting demands with a single-layer resist process, and in order to solve this problem, a pattern forming method using a three-layer resist has been proposed by Bell.
J.M. Moran of the Institute
proposed by et al. In the three-layer resist process, the lower layer is an organic polymer film that can be removed by oxygen RIE (reactive ion etching), the middle layer is an inorganic film such as polysilicon or silicon dioxide that is difficult to remove by oxygen RIE, and the upper layer is an inorganic film that is difficult to remove by oxygen RIE. A resist film forming a pattern is formed. The upper resist film is irradiated with a desired pattern and developed to obtain the desired pattern. Next, using this upper layer as a mask, a pattern is transferred to the intermediate layer of the inorganic film by dry etching. Finally, using the intermediate layer pattern as a mask, the pattern is transferred to the underlying organic polymer film by oxygen RIE to form a thick organic polymer film pattern. As described above, the three-layer structure resist has difficult problems, such as the complicated process and the need to make the inorganic film that is the intermediate layer thin and form it in a way that prevents pinholes from forming.

(Problems to be Solved by the Invention) It is an object of the present invention to solve the above-mentioned drawbacks of the prior art, to provide a method that is particularly effective for microfabrication of substrates having steps, and to provide oxygen RIE.
The object of the present invention is to provide a pattern forming material particularly suitable for use in a two-layer resist process, which has both the roles of the upper layer and the middle layer of the three-layer resist process, and has resistance to .

(Means for Solving the Problem) This object of the present invention is achieved by the following (1) or (2).

(1) A pattern-forming material characterized by containing an alkali-soluble phenol resin having a structural unit represented by general formula (1) and a diazocarbonyl compound.

H (R1 R2, same or different 0(CH2)IISIR' n=1-5 R3, R4, R5; same or different lower alkyl group or -OSiR'R&, R7, R1+, same or different lower alkyl group or phenyl group) (2) A pattern forming material characterized by containing the alkali-soluble phenol resin, diazocarbonyl compound, and alkali-soluble resin described in item (1) above.

The alkali-soluble phenol resin used in the present invention is a phenol compound represented by general formula (II) or a combination of this phenol compound and other phenol compounds (hereinafter referred to as
They can be obtained by condensing (sometimes collectively referred to as phenols) and formaldehyde.

H R' R komi (R1, RZ, same or different 0 (CHz) +
5SiR' n-1~5 R1, R4, R5, the same or different lower alkyl group or -0SiR' Ra R6, R? , Ra, the same or different lower alkyl group or phenyl group) Examples of the phenol compound giving the above general formula (II) include 2,3-bis(trimethylsilylmethoxy)phenol, 2,5-bis(trimethylsilylmethoxy)phenol, 2 , 6-bis(trimethylsilylmethoxy)phenol, 3,4-bis(trimethylsilylmethoxy)phenol, 3,5-bis(trimethylsilylmethoxy)
Phenol, 2,3-bis(3-trimethylsilylpropoxy)phenol, 2,5-bis(3-trimethylsilylpropoxy)phenol, 216-bis(3-trimethylsilylpropoxy)phenol, 3,4-bis(
3-trimethylsilylpropoxy)phenol, 3,5
-Bis(3-trimethylsilylpropoxy)phenol, 2,3-bis[tris(trimethylsiloxy)silylmethoxy]phenol, 215-bis[tris(trimethylsiloxy)silylmethoxy]phenol, 2,6-
Bis[tris(trimethylsiloxy)silylmethoxy]
Phenol, 3.4-bis[tris(trimethylsiloxy)silylmethoxy]phenol, 3.5-bis[tris(trimethylsiloxy)silylmethoxy]phenol, 2.3-bis[tris(trimethylsiloxy)silylpropoxy]phenol, 2.5-bis[tris(trimethylsiloxy)silylpropoxy]pheno-/L/,
2.6-1:l”s[tris(trimethylsiloxy)silylpropoxy]phenol, 3,4-bis[tris(
trimethylsiloxy)silylpropoxyloughenol,
3,5-bis[tris(trimethylsiloxy)silylpropoxylaphenol, 2,5-bis[tris(diphenylmethylsiloxy)silylmethoxy]phenol, 3
, 5-bis[tris(diphenylmethylsiloxy)silylmethoxy]phenol, which may be used alone or in combination. It is also possible to combine other phenolic compounds such as phenol, cresol, xylenol, ethylphenol, dihydrobenzene, trihydroxybenzene, etc., but the silicon content is required to be 5% or more.

If the silicon content is less than 5%, the resistance to oxygen RIE decreases, which is not preferable in terms of pattern formation.

The above-mentioned condensation reaction of phenols and formaldehyde can be carried out according to the conventional method described in "Phenol Resin" by Arata Murayama, Nikkan Kogyo Shinbunsha (Tokyo), etc. The molecular weight of the condensation reaction product is usually 1,000 to 50,000.

Although the alkali-soluble resin that can be combined with the alkali-soluble phenol resin having the structural unit represented by general formula (I) is not particularly limited,
Condensation reaction products of phenols and aldehydes or their hydrogenation products, condensation reaction products of phenols and ketones or their hydrogenation products, vinylphenol polymers or their hydrogenation products, isopropenylphenol-based Examples include polymers or hydrogenated products thereof, maleic anhydride polymers, acrylic acid polymers, methacrylic acid polymers, and the like.

The diazocarbonyl compound used in the present invention is
Gentabu Nagamatsu, Hideo Inui, “Photosensitive Polymers” (1980) Kodansha (Tokyo), DeForest, “Photoresist J”
(1975) McGraw-Hill Incorporated, New York), etc., but are not particularly limited to 1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphtho Quinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,1-naphthoquinonediazide-4-sulfonic acid ester, 2,1-naphthoquinonediazide-5-sulfonic acid ester or derivatives thereof ;2-diazo-cyclohexane-1,3
-dione, 5-diazo-Meldrum acid ester, 3-diazo-pyrrolidine-2,4-dione, 3-diazo-piperidine-2,4-dione, diazophosphenylketone compounds, or derivatives thereof.

The blending amount of these diazocarbonyl compounds is 1 to 100 parts by weight, preferably 3 to 30 parts by weight, based on 100 parts by weight of the total resin. If it is less than 1 part by weight, it will be impossible to form a pattern, and if it exceeds 100 parts by weight, development residues will likely occur.

The pattern forming material of the present invention is used by dissolving the above-mentioned alkali-soluble phenol resin or other alkali-soluble resin and diazocarbonyl compound in a solvent. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and ethylene glycol monomethyl. Examples include ether, glycol ethers such as ethylene glycol monoethyl ether, cellosolve esters such as methyl cellosolve acetate and ethyl cellosolve acetate, and aromatic hydrocarbons such as toluene and xylene. These may be used alone, but two or more types may be used in combination.

Furthermore, a surfactant, a storage stabilizer, an aggravating agent, an anti-striation agent, etc. can be added to the pattern forming material of the present invention, if necessary.

An aqueous alkali solution is used as a developer for the pattern forming material of the present invention, and specifically, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate, and ammonia, and primary alkali solutions such as ethylamine and propylamine are used. Amines, tertiary amines such as diethylamine and dipropylamine, tertiary amines such as trimethylamine and triethylamine, alcohol amines such as diethylethanolamine and triethanolamine, tetramethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide , quaternary ammonium salts such as tetraethylammonium hydroxide, and the like.

Furthermore, if necessary, add methanol or
Appropriate amounts of water-soluble organic solvents such as ethanol, propatool, and ethylene glycol, surfactants, and resin dissolution inhibitors can be added.

(Example) The present invention will be described in more detail with reference to Examples below. Note that parts and percentages in each example are based on weight unless otherwise specified.

1 A reflux condenser and a dropping funnel were attached to a three-bottle flask, and 500 mj2 of ethanol and 33 g of metallic sodium were added thereto and thoroughly stirred. When the solution became homogeneous, 66 g of phloroglucinol was added, stirring was continued for 1 hour under reflux, and 130 g of chloromethyltrimethylsilane was added under reflux.
g was slowly added dropwise, and refluxing was continued for an additional 40 hours. After slow cooling, ethanol was removed under reduced pressure, 70 g of pure water was added, the pH was adjusted to 6 with hydrochloric acid, and the mixture was extracted with chloroform and washed with water.

Chloroform was distilled off from the chloroform solution to obtain a residue. This residue was collected and purified by column chromatography using carbon tetrachloride/chloroform as a developing solvent to obtain a monomer.

As a result of analyzing this monomer by NMR and mass spectroscopy, it was confirmed that it was 3,5-bis(trimethylsilylmethoxy)phenol.

20.9 g of this 3,5-bis(trimethylsilylmethoxy)phenol and 4.0 g of phloroglucinol.

Formalin 0.9g, ethyl cellosolve acetate 22
g, and 0.5 g of oxalic acid were placed in a 100 mf eggplant flask and uniformly dissolved. After reacting at 100°C for 8 hours, the reaction solution was washed with water and purified under reduced pressure to obtain a polymer.

When this polymer was analyzed by GPC, the weight average molecule f
i(M w) = 5200, molecular weight distribution (MWD) = 3
．． It was 4.

Reference Example 1 2,5-bis(trimethylsilylmethoxy)phenol was synthesized in the same manner as in Reference Example 1.

A polymer was prepared using 20.9 g of this 2,5-bis(trimethylsilylmethoxy)phenol, 3.5 g of phloroglucinol, 0.9 g of formalin, 25 g of ethyl cellosolve acetate, and 0.6 g of oxalic acid in the same manner as in Reference Example 1. did.

When this polymer was analyzed by GPC, Mw=4200.
, MWD=3.6.

Reference 3.5-bis(trimethylsilylbropoxy)phenol was synthesized in the same manner as in Reference Example 1.

A polymer was prepared in the same manner as in Reference Example 1 using 20.9 g of this 3.5-bis(trimethylsilylpropoxy)phenol, 6.5 g of resorcinol, 0.7 g of formalin, 30 g of ethyl cellosolve acetate, and 0.7 g of oxalic acid. did.

When this polymer was analyzed by GPC, it was found that Mw-6200
, MWD=4.2.

100 parts of the resin of Reference Example 1, 2,3.4-)rihydroxyhenzophenone and 1,2-naphthoquinonediazide-5
- 15 parts of sulfonic acid ester was dissolved in 1-500 parts of ethyl cellosolve acetate, and the solution was filtered through a 0.1 μm Teflon filter (manufactured by Millibore) to prepare an upper layer resist solution.

First, a commercially available positive resist AZ-1350J was applied onto a silicon wafer using a spinner, and then beta-coated at 200°C for 30 minutes to form a 1.5 μm thick lower layer film. Next, the above upper layer resist solution was mixed with AZ-1350.
After coating with a spinner on a silicon wafer on which the lower layer film of J was formed, it was betatized at 85°C for 30 minutes to give a 0.5μ
An upper layer resist of m was formed to prepare a wafer for exposure.

This exposure wafer was exposed using an FPA4550 (manufactured by Canon) stepper and a test reticle, and was exposed to a tetramethylammonium hydroxide aqueous solution at 23°C.
The upper resist film was developed by dipping for 1 minute to obtain a positive pattern.

Using this upper layer resist as a mask, oxygen RIE (pressure 2 × 10-” torr, oxygen flow rate 20 SCCM, power 400 W, RF frequency 13
．． 56 Hz) to transfer the pattern to the lower layer film.

When the patterned wafer was taken out and inspected under an optical microscope, it was found that the lower layer that was not covered by the upper layer on which the test pattern was formed had been completely removed. The film thickness of the part covered by the upper layer on which the test pattern was formed was 1.8 μm when measured with a film thickness meter Alpha Step 200 (manufactured by Tenco), forming a pattern that faithfully reflected the test pattern of the reticle. I was able to do that.

100 parts of the resin of Reference Example 2, 2,3.4-1-lihydroxybenzophenone and 1,2-naphthoquinonediazide-5
- 20 parts of sulfonic acid ester was dissolved in 500 parts of ethyl cellosolve acetate, and the solution was filtered through a 0.1 μm Teflon filter (manufactured by Millibore) to prepare an upper layer resist solution.

First, a commercially available positive resist AZ-1350J was applied onto a silicon wafer using a spinner, and then beta-coated at 200°C for 30 minutes to form a 1.4 μm thick lower layer film. Next, the above upper layer resist solution was mixed with AZ-1350.
After coating with a spinner on the silicon wafer on which the lower layer film of J was formed, it was beta-coated at 90°C for 10 minutes to give a 0.6μ
An upper layer resist of m was formed to prepare a wafer for exposure.

When this exposure wafer was patterned under the same conditions as in Example 1, the film thickness of the portion covered by the upper layer on which the test pattern was formed was 1.8 μm, and a pattern that faithfully reflected the test pattern of the reticle was obtained. was able to form.

Example 111: 100 parts of the resin of Reference Example 3 and 15 parts of ester of 2,3,4.4'-tetrahydroxybenzophenone and 1,2-naphthoquinonediazide-5-sulfonic acid were dissolved in 500 parts of ethyl cellosolve acetate. A resist solution for the upper layer was prepared by filtration with a 0.1 μm Teflon filter (manufactured by Millibore).

When buttering was performed using this upper layer resist solution under the same conditions as in Example 1, the film thickness of the portion covered by the upper layer where the test pattern was formed was 1.7 μm, which faithfully reflected the test pattern of the reticle. We were able to form a pattern that

100 parts of the resin of Reference Example 1 and 20 parts of 2-diazocyclohexanone-1,3-dione were dissolved in 500 parts of ethyl cellosolve acetate and filtered with a 0.1 μm Teflon filter (manufactured by Millibore). A resist solution for the upper layer was prepared.

First, a commercially available positive resist AZ-1350J was applied onto a silicon wafer using a spinner, and then baked at 200°C for 30 minutes to form a 1.4 μm thick lower layer film. Next, the above upper layer resist solution was mixed with AZ-1350.
After coating with a spinner on the silicon wafer on which the lower layer film of J was formed, it was baked at 90'C for 10 minutes to give a 0.6
A wafer for exposure was prepared by forming an upper layer resist of μm.

This exposure wafer was exposed using an excimer laser device C2926 (manufactured by Hamamatsu Photonics) filled with krypton/fluorine gas and a test reticle, and then patterned under the same conditions as in Example 1. The film thickness of the part covered by the formed upper layer was 1.8
It was possible to form a pattern that faithfully reflected the test pattern of the reticle.

1 ship ■ 80 parts of the resin from Reference Example 1, 20 parts of polyvinylphenol,
20 parts of 5-diazomeldrum acid was dissolved in 500 parts of ethyl cellosolve acetate, and the solution was filtered through a 0.1 μm Teflon filter (manufactured by Millibore) to prepare an upper layer resist solution.

This wafer for exposure is exposed to deep ultraviolet irradiation equipment PLA-521.
When irradiated with i-light using FA (manufactured by Canon) and a test reticle, and then buttered under the same conditions as in Example 1, the film thickness of the portion covered by the upper layer on which the test pattern was formed was 1. It was 8 μm, and it was possible to form a pattern that faithfully reflected the test pattern of the reticle.

(Effects of the Invention) According to the present invention, since the alkali-soluble phenol resin having the structural unit of general formula (1) has a high St content, a pattern forming material suitable as an upper layer resist with excellent oxygen RIE resistance is obtained. can get.

Patent applicant: Zeon Corporation

Claims (2)

[Claims] (1) A pattern-forming material characterized by containing an alkali-soluble phenol resin having a structural unit represented by general formula (I) and a diazocarbonyl compound. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (R^1, R^2; Same or different ▲There are mathematical formulas, chemical formulas, tables, etc.▼ n = 1 to 5 R^3, R^4, R ^5; Same or different lower alkyl group or ▲ Numerical formula, chemical formula, table, etc. ▼ R^6, R^7, R^8; Same or different lower alkyl group or phenyl group) (2) A pattern forming material containing the alkali-soluble phenol resin, diazocarbonyl compound, and alkali-soluble resin according to claim (1).