JPS62255934A - Negative type photoresist composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition having a good coating characteristics such as flexibility by incorporating a specific N-(hydroxyphenyl)-maleimide copolymer, a novolak resin and a photosensitive aromatic azide compd. to the titled composition. CONSTITUTION:(1): The N-(hydroxyphenyl)-maleimide polymer polymerized from constitution units shown by formulas I, II, and III wherein R1 is aryl, 1-16C alkyl or cycloalyl grop, R2 is hydrogen atom or lower alkyl group, a ratio of (n), (l) and (m) satisfys the following formulas; 0.01<n/(l+m)<=10 and 0.1<l/(l+m)<=1. (2): The novolak resin is used for one component of the titled composition. (3): The photosensitive aromatic azide compd. is exemplified by the compd. contg. at least one of the aromatic azide group in one molecule, for example, 4-azidoenzal acetophenone, etc. The titled composition is obtd. by incorporating the compds. (1), (2) and (3), Thus, the photoresist composition having the excellent sticking property against a substrate and heat-resisting property is obtd.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a negative photoresist composition, specifically, an alkali-soluble N-(hydroquinphenyl)maleimide copolymer made of a novolac resin as a raw material. The present invention relates to a negative-tone photoresist composition that improves film performance, adhesion to a substrate, and heat resistance by blending it into a negative-tone photoresist. In addition to being used for the production of masks, printed wiring boards, PS thousand printing plates, and photo relief printing, it can also be used for the formation of ordinary wiring patterns and the production of integrated circuits such as ICs and LSIs. Widely used in fields such as electronic industry.

[Conventional technology]

Conventionally, compounds having an azide group have been widely used in negative photosensitive materials by taking advantage of the fact that the and group decomposes when irradiated with ultraviolet rays, and the solubility of the ultraviolet irradiated part changes due to the reaction of nitrene produced by the decomposition. It is widely used industrially as a negative photoresist, for example, in the production of lithographic printing plates and the production of integrated circuits.

Compounds having such an azide group are mixed with an alkali-soluble novolac resin, such as a phenol formaldehyde novolac resin or a talezol formaldehyde novolac resin, and are widely put into practical use as negative photoresists that exhibit little swelling and can be developed with an alkali. There is.

[Problem that the invention seeks to solve]

Due to the physical properties and low molecular weight of the novolac resin, the film of the negative photoresist composition made from the above-mentioned novolac resin lacks flexibility and is brittle, and image defects due to impact are difficult to remove. The adhesion to the substrate is still unsatisfactory (-min.).

Therefore, an object of the present invention is to provide a negative photoresist composition that is flexible, has good film performance, and has excellent adhesion to a substrate.

[Means for solving problems]

As a result of various studies, the present inventors found that a specific N-(hydroxyphenyl)maleimide copolymer could be used as a novolac resin. It has been found that by using Fi and combining it with a specific azide compound, a negative photoresist composition that achieves the above object can be obtained, and the composition also has excellent heat resistance.

The present invention was made based on the above findings, and includes (wherein,
R is an aryl group, an alkyl group having 1 to 16 carbon atoms or a cycloalkyl group, and R2 is hydrogen or a lower alkyl group. Moreover, the ratio of n and (1+m) and the ratio of 2 and (R14-m) are each 1 + m 1
+m. The present invention provides a negative photoresist composition containing an N-(hydroxyphenyl)maleimide copolymer having the structural unit represented by the following formula, a novolac resin, and a photosensitive aromatic azide 1' compound.

The negative photoresist composition of the present invention will be explained in detail below.

N constituting the negative photoresist 14fl composition of the present invention
-(Hydroxyphenyl)maleimide copolymer, (wherein R1 is an aryl group, an alkyl group having 1 to 16 carbon atoms, or a cycloalkyl group, and R2 is hydrogen or a lower alkyl group. 8 combinations of n and N!+m) and l and N! +m) is 1+m 1+m, preferably 1 +41 z +m, respectively. ) It is a copolymer having a structural unit represented by the above formula (
Examples of suitable unsaturated hydrocarbon compounds constituting the structural unit represented by 1u) include isobutylene, 3-methylbutene-11hexene-11styrene, α-methylstyrene, vinyltoluene, vinylylfurylene, vinylcyclohexane, vinyl 2ρ of cyclohexane etc. is obtained.

Regarding the N-(hydroxyphenyl)maleimide copolymer described in L, it is easier to obtain a thin film with excellent flexibility when the unsaturated hydrocarbon compound has only an alkyl group than when the unsaturated hydrocarbon compound has an aryl group. This is preferable because it also has excellent adhesion to the surface.

The above N-(hydroxyphenyl)maleimide copolymer has 91 bonds of n and (j!4-m) (n/(1+m))
If it exceeds lO, the alkali solubility will decrease, and if the ratio of n and (1+m) is too small, the film will become weak or stale, which is not appropriate.Also, if l and (j!+m) If the ratio C1/C1+m) is 0.1 or less, there is not much difference in alkali solubility between irradiated and non-irradiated areas in the photoresist, which is not appropriate.

Further, in the N (hydroxyphenyl) maleimide copolymer, the proportion of the structural unit represented by formula (1), that is, the proportion of l and (1+m+n) is 0, 2 < 1 / (
1+ m 10n) < Q, 13, especially 0.25
<1 / (j! + m + n) < Q, 6
It is preferable that

The N-(hydroxyphenyl)maleimide copolymer has a number average molecular IEt (rn) of 1,000 as determined by gel permeation chromatography (GPC method) using monodisperse polystyrene as a standard. ~500,00
It is preferable to use a photoresist having a molecular weight of 0.0, particularly 4,000 to 200.000, since this yields a photoresist particularly excellent in sensitivity, resolution, heat resistance, film formability, etc.

Furthermore, the above N (hydroxyphenyl)maleimide copolymer has a glass transition temperature (Tg) of 160 to 2.
It is preferable to use one having a temperature of 60'C, especially 170 to 250C.

The N-(hydroxyphenyl)maleimide copolymer can be obtained by, for example, reacting a copolymer obtained by copolymerizing maleic anhydride with the unsaturated hydrocarbon compound and aminophenol in an organic solvent. It can be produced by a method of converting part or all of the maleic anhydride component into an N-(hydroquinphenyl)maleamic acid component and then carrying out a cyclization dehydration reaction. In addition, as shown in Kobunshi Kagaku, Vol. 26, p. 598 (1969), N-(p-hydroquinphenyl)maleimide monomer synthesized by transesterification 1tA reaction via maleimide with esterified hydroxyl group. An N-(p-hydroxyphenyl)maleimide-styrene copolymer can also be produced by copolymerizing N-(p-hydroxyphenyl)maleimide and styrene.

Further, a suitable novolak resin constituting the negative photorenost composition of the present invention is an alkali-soluble novolak resin obtained by addition-condensation reaction of phenol-formaldehyde and formaldehyde. Addition of formaldehyde with a mixture of two or more selected from resin, 0-talesol formaldehyde novolak resin, m-talesol formaldehyde novolak resin, p-talesol formaldehyde novolak resin, phenol and cresol isomers. Examples include novolac resins obtained by condensation reactions, phenol-modified xylene resins, and the like.

The above novolac resin has a weight average molecular weight of 500 as determined by GPC method using monodisperse polystyrene as a standard.
~20,000, preferably 1,000-10,000. If the weight average molecular star is less than 500, sufficient coating performance cannot be obtained. If it exceeds 20,000, the solubility in alkaline aqueous solution is poor. low.

In addition, as the photosensitive aromatic azide compound constituting the negative photoresist composition of the present invention, a small amount of (
Preferably, both have one aromatic azide group, and specifically, 4-azidobenzal-4-methoxyacetophenone, 4-azidobenzal-7setone, 3-(4-(p- azidophenyl)-1,3-butadienyl)-5,5-dimethyl-2
-cyclohexen-1-one, azidopyrene, 4°4'
-Noacytochalcone, 2,6-bis(4”-azidohenzal)cyclohexanone, 1,3-bis(4°-azidohenzal)-2-propanone, t,3-bis(4°-
7)-2-propanone-2°-sulfone P
a, 2,6-bis(4′-atstyryl)-4-methylcyclohexanone, 2,6-bis(4″-azidostyryl)-4-t-phthylcyclohexanone, 4.
4'-Diazidiphenylmethane, 4.4'-Diazidiphenyl ether, 4.4'-Diazidobenzophenone, 4,4'-Diazidiphenyl sulfide, 4,4'-Diazidiphenyl disulfide,
Examples include 4.4°-diazidodiphenylsulfone, 3°3′-diazidodiphenylsulfone, and 2.2''-diazidocytostilbene.

The amount of the photosensitive aromatic azide compound used varies depending on the type of the and compound used and the type and combination of the N-(hydroxyphenyl)maleimide copolymer and the novolac resin, but the amount of the N-(hydroxyphenyl) Roughly 1 to 50% by weight, particularly 10 to 40% by weight based on the total of the maleimide copolymer and the novolak resin
It is preferable to keep it within the range of .

If the amount of the photogenic aromatic azide compound used is less than 1% by weight, the curability will be insufficient, and if it is more than 50ffi1%, the physical properties of the coating will deteriorate.

Further, the ratio of the N-(hydroxyphenyl)maleimide copolymer and the novolak resin to the novolak resin is such that the N-(hydroxyphenyl)maleimide copolymer is
Maleimide copolymer at least 10% by weight, especially 15% by weight
The negative photoresist daily composition of the present invention, which is preferably used as described above, is soluble in an organic solvent, and is generally added in an aqueous solvent at a ratio of 1 to 50% by weight, preferably 5 to 30% by weight. (dissolved) volume; night (resist) solution). As this organic solvent,
A uniform and smooth coating film can be obtained by uniformly dissolving each component of the negative photoresist composition of the present invention and applying it to the surface of a silicon, aluminum, etc. plate, and then evaporating the organic solvent. Specific examples thereof include ketone solvents such as acetone, methyl ethyl ketone, and cyclohexanone, and cellosolve solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, and ethyl cellosolve acetate. The above ionic solvents may be used alone or in combination of two or more.

In addition, the above resist solution may contain a plasticizer,
Dyes, other resins, various inhibitors, adhesion improvers, etc. can be added.

According to the negative photoresist composition of the present invention, by preparing the resist solution as described above, it has a flexible and good skin 119 performance, which is formed into a pattern as follows, for example. It is possible to obtain a photocuring level of 11.

1! II. First, the above-mentioned resist solution is applied to the substrate and dried to remove the organic solvent. Coating onto the substrate can be performed using, for example, a spin cord (rotary coating). In addition, the coating film is preferably dried by a method such as heat I@drying, far-infrared drying, or drying on a hot plate.
The temperature is preferably 20° C. or lower, more preferably 100° C. or lower. At this time, the pressure may or may not be reduced.

After drying, a mask is placed on the coating film, and light is irradiated using, for example, an ultra-high pressure mercury lamp, a low-pressure mercury lamp, or the like.

Next, this is developed by spraying a developing solvent or immersing it in a developing solvent, and the non-exposed portions are dissolved and removed to obtain a photocured film formed in a pattern. As the developing solvent, a weak alkaline aqueous solution of sodium hydroxide, potassium hydroxide, sodium metasilicate, tetramethylammonium hydroxide, tertiary sodium phosphate, etc., having a concentration of 5% by weight or less, can be used.

Further, the substrate can be etched using the photocured film formed in a pattern as described above using the negative photoresist t4ft of the present invention as a mask.

〔Example〕

Below are examples of the synthesis of N-(hydroquinphenyl)maleimide copolymer, which is the t14 component of the negative photoresist composition of the present invention, examples of the present invention, and negative photoresists and compositions of the present invention. Using, fine pattern formation,
The invention will be explained in more detail by giving examples of use in the production of lithographic printing plates and printed wiring boards.

Synthesis Examples 1 to 6 Maleic anhydride copolymer and aminophenol shown in Table 1 below were dehydrated with 150% dimethylformamide.
After dissolving in ml and reacting at 80°C to produce an N-(hydroxyphenyl)maleamic acid copolymer,
12 g of trilobnal amine as a catalyst and 45 +++ l of toluene as an azeotropic solvent were added, and a cyclization and dehydration reaction was carried out at 140°C. After the completion of the 6 reactions, the polymer was precipitated with ethyl ether, and tetrahydrofuran t8-ethyl ether was added. It was purified by precipitation and dried under vacuum at 100°C for 24 hours to obtain N-(
A hydroxyphenyl)maleimide copolymer was obtained.

? jE) j'l Manufactured by Clarei Soprene Chemical Co., Ltd., trade name Isohan-04 (copolymerization ratio 1:1) fbl Kawasaki Crude Oil Co., Ltd., trade name SMA-1000 (copolymerization ratio 1:1) (cl with maleic anhydride FDL is obtained by polymerizing α-methylstyrene with azobisisobutyronitrile (AIBN) at 60°C. This is the modification rate.This modification rate was determined by the nitrogen content in elemental analysis and was expressed as a ratio to the maleic anhydride component in the maleic anhydride copolymer [namely, -X I OO].

The average molecular weight (lower) and the ratio of weight average molecular weight to number average molecular weight (de/6) were each determined by the GPC method using monodisperse polystyrene as a standard.

(') Glass transition temperature (Tg) was measured with a DuPont 990 Thermal Analyzer DSC.

Examples 1 to 8 and Comparative Example 1 According to the conditions shown in Table 2 below, N-(hydroquinophenyl)maleimide copolymer, m-cresol formaldehyde novolanc internal fat (weight average molecular 173,200) and photosensitizer were used. 4-Andhenzalacetophenone to cyclohexanone? Each resist was dissolved to prepare a resist solution.

Further, a resist solution was prepared by dissolving m-talesol formaldehyde novolanque resin and 4-azidobenzalacetophenone as a photosensitizer in cyclohexanone under the conditions shown in Table 2 below, and used as a comparative example.

These Regis)? Test pieces were prepared using Liquid V as described below, and a bending resistance test was conducted on these test pieces according to the bending resistance test method described below.

(Preparation of test piece) A grained aluminum plate of 50 mm x 5 Q mm and a thickness of 0.2 ms+ was packed well, dried, and the above resist solution was spin-coated on the aluminum plate, and dried to form a film. A coating film with a thickness of approximately 2 μm (see Table 2 below) is formed. Next, this coating film was fully exposed to light for 40 seconds from a distance of 70cI11 using a 3KW ultra-high pressure mercury lamp, and then
The sample was immersed in 3% tertiary sodium phosphate solution (I8) and stirred for 3 minutes, washed with water, and dried to obtain a test piece. The test piece is each resist 78
Prepare 3 pieces for each liquid.

(Bending resistance test method) Using a bending tester specified in JIS 5400 (paint-touch test method), the above test piece was bent 180 degrees around a mandrel with a constant diameter, and the coating 11 of the bent part was bent. I will check for T1 debris. However, since the diameter of the mandrel of the tester is 10 m11 or less, the bending resistance test using a mandrel with a diameter of 20 m11+ was conducted by bending the pipe 180 degrees into a pipe with a diameter of 20III11.

The bending resistance is so good that it can withstand small diameter mandrels.

The results of the above bending resistance test are shown in Table 2 below.

This result was confirmed for two or more of the three test pieces.
Riniware,? , 11 peeling was not observed as ○, and when it was observed, it was indicated as ×, and this was used as an index of the flexibility of coating 11.

Examples 9 to +1 and Comparative Example 2 According to the conditions shown in Table 3 below, N-(hydroxophenyl)maleimide copolymer, m-talesol formaldehyde novolak resin (weight average molecular weight ht: 3,200
) and l-azidopyrene as a photosensitizer were dissolved in cyclohexanone to prepare resiston solutions, respectively.

Further, a resist solution was prepared by dissolving m-talesol formaldehyde novolac resin and l-azidopyrene as a photosensitizer in cyclohexanone under the conditions shown in Table 3 below, and used as a comparative example.

Using these resist solutions, test pieces were prepared in the same manner as in Example 1, and the same bending resistance test as in Example 1 was conducted on these test pieces. The results are shown in Table 3 below.

Usage Examples 1 to 4 Each resist solution B prepared in Example 2.6.8 and IO
The solution was heated to 500°r, p, m on a silicon wafer, respectively.
, and dried at 80° C. for 20 minutes to obtain a coating film having a thickness of about 1 μm (see Table 4 below).

Next, a chrome mask with a pattern was closely attached to the coating film, and a wavelength of 30
The coating film was irradiated with 0 to 500 nlI+ light (UV light) through the chrome mask and exposed for the time shown in Table 4 below. This was developed with a 2% aqueous solution of tetramethylammonium hydroxide, and the non-exposed portions were dissolved and removed to obtain photocured films formed in a pattern.

When all of the photo-cured films in the current pattern were observed using an electron microscope, it was found that a repeating pattern of lines/spaces of 1. The film had excellent properties with no cracks or pinholes.

Furthermore, the T value and sensitivity to UV light of the negative photoresist composition of the present invention used were measured as follows. The results are shown in Table 4 below.

- γ value: A coating film made of the negative photoresist composition of the present invention is prepared as described above, and this coating film is exposed and developed. By varying the amount of light irradiation, the relationship between the amount of light irradiation and the resist film thickness after development (normalized residual film thickness) is measured. From the measurement results, the characteristic curve is defined as the curve where the horizontal axis is the light irradiation amount (logarithm) and the vertical axis is the residual film rate (ratio of resist film thickness after development to the resist film thickness). A numerical value indicating the slope of the rising portion of is determined and taken as the T value.

・Sensitivity: In the measurement of the above characteristic curve (γ value), the residual film rate is 0.5
(50%) (Irradiation at time D!it (Dg'·') was defined as sensitivity.

Table 4 Usage Example 5 A grained aluminum plate of 1F1 x 0.2 mII was thoroughly rubbed and dried, and the resist solution prepared in Example 2 was spin-coated on the aluminum plate, and dried. A negative-type PS thousand plate of 112J￥2.0 μm was prepared.Next, a halftone negative film was closely adhered to this PS plate,
After exposing the above halftone negative film for 40 seconds using a 3KW ultra-high pressure mercury lamp from a distance of 70Cffi, the film was immersed in a 3% aqueous solution of sodium phosphate for 3 minutes, stirred, and the unexposed areas were dissolved and removed, and washed with water. As a result, a fixed image in which halftone dots of 100 lines per 1 cm were formed with high accuracy was obtained. This fixed image line had excellent flexibility and was easy to absorb fatty printing ink, and could be used for offset printing as a lithographic printing plate in the presence of dampening water.

Usage Example 6 The resist solution prepared in Example 2 was spin-coated onto a printed wiring board on which 5R4ft3 with a thickness of 35 μm was laminated, and dried to obtain a film with a thickness of 1.7 μm. A negative film was tightly attached on top and exposed for 40 seconds through the negative film from a distance of 70cI11 using a 3KW ultra-high pressure mercury lamp, and then immersed in a 3% aqueous solution of tribasic sodium phosphate for 3 minutes with stirring to remove the unexposed areas. A resist film was formed on the printed wiring board by dissolving and removing and washing with water. After drying, the copper foil was etched with a ferric chloride solution (408 g), and then the resist film was dissolved and peeled off with a 4% aqueous sodium hydroxide solution at 40° C. to obtain a printed wiring board.

〔Effect of the invention〕

The negative photoresist composition of the present invention has good film properties with flexibility, and has excellent adhesion to a substrate and heat resistance.Moreover, since it is easily developed with an alkaline aqueous solution, it does not have the habit of swelling. It is capable of forming fine photoresist patterns with high precision.
Printed wiring boards, 1) Can be used for the production of S lithography, photo letterpress, etc., as well as for forming ordinary wiring patterns, IC and LS
It can be used in the production of integrated circuits such as I, and can be used in a wide range of fields such as the photographic industry, the printing industry, and the electronic industry.

Claims (1)

[Claims] (1) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 is an aryl group, having 1 to 16 carbon atoms. It is an alkyl group or a cycloalkyl group, and R_2
is hydrogen or a lower alkyl group. Also, n and (1+m
) and the ratio between l and (l+m) are 0.01<n/(l+m)≦10 and 0.1<l/(l
+m)≦1. ) A negative photoresist composition comprising an N-(hydroxyphenyl)maleimide copolymer having the structural unit represented by the following formula, a novolac resin, and a photosensitive aromatic azide compound.