JP2001255657A - Positive type photosensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive type photosensitive resin composition which satisfies heat resistance, adhesion and low dielectric properties and can form a good image. SOLUTION: The positive type photosensitive resin composition comprises (A) an organic solvent-soluble polyimide having an acid group, (B) a diethyl vinyl ether which imparts low dielectric properties and (C) a photo-acid generating agent. A coating of the photosensitive resin composition is irradiated with UV through a mask and the irradiated part is leached with an aqueous alkali solution to obtain a positive type heat resistant relief.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photosensitive resin composition useful as a protective insulating film for a semiconductor device, an alignment film for a liquid crystal device, an insulating film for a multilayer printed board, and the like.

[0002]

2. Description of the Related Art Heat-resistant photoresists using photosensitive polyimides or precursors thereof and their uses are well known. For example, ester bonding to a polyimide precursor as a negative photoresist (Japanese Patent Laid-Open No. −
115541) and ionic bonds (JP-A-54-14579).
Those in which a group capable of photocrosslinking according to 4) is introduced have been put to practical use.

On the other hand, as a positive resist, a method of mixing naphthoquinonediazide with a soluble hydroxylimide or polyoxazole precursor (Japanese Patent Publication No. 64-6063).
A number of methods using various types of naphthoquinonediazides including 0) have been proposed. Also, a chemically amplified polyimide (JP-A-3-763) has been reported.

[0004] However, the negative type polyimide has a problem in resolution in terms of its function and a problem in film forming properties, and is not suitable for some applications. On the other hand, in the case of using a positive type polyimide, when a precursor is used, there is a problem that the film is reduced due to a high temperature treatment after image formation. In addition, although these polyimide resists have been devised as materials for forming protective films and insulating films for solid-state devices and circuit boards in the semiconductor industry, they have low dielectric properties to respond to the recent trend toward higher frequencies in information and communication equipment. Has not been considered. Therefore, the photosensitive polyimide with current high-temperature treatment has dielectric properties comparable to conventional non-photosensitive polyimide, and the photosensitive polyimide without high-temperature treatment contains denaturing agents and additives. It is expected that the dielectric constant of the polyimide is higher than that of ordinary polyimide since it contains a modifying agent and additives.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-resistant, positive-type photosensitive resin having low dielectric properties while satisfying the general characteristics such as sensitivity and resolution of a conventional photosensitive polyimide. It is to provide a composition.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a partly alicyclic compound or a fluorine-containing compound (A) is used as a polyimide component, and

A composition which can achieve the above object of the present invention by blending a vinyl ether compound (B) giving a specific low dielectric property shown by (1) with a photoacid generator (C) is obtained. We have found what we can do and have completed the present invention.

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That is, as the heat-resistant positive photosensitive polyimide of the present invention, acid anhydrides and diamines conventionally used in the synthesis of polyimide can be used. In other words, as an acid anhydride

It is a dianhydride shown in the following formula.

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On the other hand, as a diamine,

And those having an acid group

It is a diamine represented by the following formula.

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It is well known that a fluorine-containing compound or a silicone-containing compound is used together with an acid anhydride and a diamine to synthesize a low dielectric polyimide. Are preferred, those having no polar group, and alicyclic compounds are preferred.

However, when used as a photosensitive polyimide, there is a contradiction in which a molecule cannot be designed mainly for a low dielectric substance in order to provide a function or to obtain characteristics in use. It is the one that can be satisfied at least according to the application, and settles in the range of lower dielectric constant than the conventional product.

In view of the above, the present invention proposes a low-dielectric positive photosensitive resin composition by blending a diethyl vinyl ether compound as a cross-linking agent for imparting low-dielectric properties in order to reduce the dielectric properties by taking the compromise.

Since the ethyl vinyl ether group is ester-bonded to the acid group by a thermal reaction, the compound containing diethyl vinyl ether crosslinks with the polyimide having an acid group by a thermal reaction, and the acid group is lost, so that the compound becomes insoluble in an aqueous alkaline solution. It has been confirmed that a commercially available aliphatic compound as diethyl vinyl ether is scattered at the stage of performing a thermal reaction and does not crosslink polyimide. Therefore, in the present invention, diethyl vinyl ether having a bisphenol type skeleton having a high boiling point and high heat resistance which is not scattered at all during the thermal reaction is used.

In examining the dielectric constant when the bisphenol skeleton is epoxidized, the more the substituents are attached to the aromatic nucleus of bisphenol, and the larger and bulky the aromatic nucleus is, the lower the dielectric constant becomes. It is reported that the dielectric constant becomes smaller when inserted. (Sumitomo Chemical Fine Chemicals Laboratory Report 1995
-I)

[0014]

The vinyl ether compound represented by the formula (1) is represented by R
It can be obtained by reacting 2-chloroethyl vinyl ether with a biphenol compound having a substituent of 1, R2 and R3. Commercially available aliphatic vinyl ethers can also be used, but they can also be used together with a photosensitive resin composition having a boiling point that does not evaporate and scatter during prebaking.

The vinyl ether compound is used in an amount of 1 to 100 parts, preferably 10 to 100 parts by weight, based on 100 parts by weight of the polyimide.
It is contained in the range of 60 parts by weight. When the content is 10 parts by weight or less, the unexposed film is greatly reduced during development due to insufficient crosslinking, and when the content is 60 parts by weight or more, excess vinyl ether that cannot be cross-linked is present, so that the film is heated at a high temperature. It is not preferable because the decrease is large and the physical properties of the final film are adversely affected.

Examples of the photoacid generator, which is one of the photosensitive resin compositions of the present invention, include onium salts such as diallylsulfonium salts, triallylsulfonium salts, dianisylphenacylsulfonium salts, aromatic tetracarboxylic acid esters, and aromatic tetracarboxylic acid esters. Aliphatic sulfonic acid esters, nitrobenzyl esters, aromatic sulfamides, naphthoquinonediazido acid esters and the like.

These compounds are those of the above-mentioned polyimide 100
It is contained in an amount of 1 to 50 parts by weight, preferably 1 to 20 parts by weight based on parts by weight. When the content is 1 part by weight or less, the solubility contrast tends to be unclear due to insufficient light sensitivity when irradiated with light, and when the content is more than 50 parts by weight, the storage stability of the photosensitive resin solution is deteriorated or after light irradiation. It also has an adverse effect on developability.

A desired pattern is formed from the positive photosensitive resin composition of the present invention under the following mechanism.
In other words, the photosensitive resin composition is applied to the support and then dried to disperse the solvent. In this step, the vinyl ether group undergoes a crosslinking reaction with the acid group of the polyimide by heat. Thereafter, when the coating film is exposed through a mask, the photo-irradiated portion acts on the irradiated portion to generate an acid. When the exposed coating film is heated, the generated acid decomposes the bond between the vinyl ether group and the acid group of the polyimide by heat. The decomposed exposed portion returns to the previous polyimide having an acid group, becomes alkali-soluble, and has a dissolution contrast with the non-exposed portion, so that a desired positive pattern can be obtained.

In the image forming method using the positive photosensitive resin composition of the present invention, the composition is first applied to a suitable support, for example, a silicon wafer, an aluminum substrate, a copper plate or the like. Coating is performed by spin coating using a spinner, spraying, dipping, printing, roll coating, or the like. Next, 90-13
After pre-baking at 0 ° C. and drying the coating film, it is irradiated with ultraviolet rays in a desired pattern shape. Next, post-baking is performed at 80 to 150 ° C. to dissolve and remove the irradiated portion with a developer. Examples of the developer include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate and sodium silicate; primary amines such as ethylamine and n-propylamine; and secondary amines such as diethylamine and di-n-propylamine. Diamines,
Triethylamine, tertiary amines such as methyldiethylamine, dimethylethanolamine, alcoholamines such as triethanolamine, tetramethylammonium hydroxide, aqueous solutions of alkalis such as quaternary ammonium salts such as tetraethylammonium hydroxide, and An aqueous solution to which an appropriate amount of a water-soluble organic solvent such as alcohol such as methanol or ethanol or a surfactant is added can be suitably used. Finally, the relief pattern formed by development is rinsed with distilled water or distilled water containing alcohol.

The photosensitive resin composition according to the present invention is useful not only for semiconductor applications but also for interlayer insulation of multilayer circuits, cover coats of flexible copper clad boards, solder resist films and liquid crystal alignment films.

Hereinafter, the present invention will be described specifically with reference to examples. Embodiment 1 FIG. 13.2 parts by weight of maleic methylcyclohexane tetrabasic anhydride and 3,5 diaminobenzoic acid 15 in a 1 l four-necked flask equipped with a polyimide synthetic tablet stirrer, a condenser with a nitrogen inlet tube and a flocculated water collecting tube. 2 parts by weight, 100 parts by weight of N-methylpyrrolidone, 20 parts by weight of toluene,
-A solution in which 3 parts by weight of ethylhexyl is dissolved is stirred at room temperature under a nitrogen atmosphere, and after one hour, immersed in an oil bath which has been heated to 185 ° C in advance, and reacted for 2 hours. Thereafter, the oil bath was removed, the reactor was returned to room temperature, and 24.8 parts by weight of bicyclooctenoic dianhydride, 46.7 parts by weight of diaminooxysilane, 100 parts by weight of N-methylpyrrolidone, and 20 parts by weight of toluene were injected. Similarly, after stirring at room temperature for 1 hour, the mixture is immersed in an oil bath at 185 ° C. and reacted for 4 hours to obtain a black highly viscous polyimide solution. This solution was dropped into methanol while stirring, and an off-white precipitate produced was 83.6 parts by weight after drying. (Acid value: 59.3) Synthesis of diethyl vinyl ether 33.6 parts by weight of 2,2-bis (4-hydroxyphenyl) hexafluoropropane and 50 parts of dimethyl sulfoxide
The weight part is put into a 1 l four-necked separable flat bottom flask and dissolved by stirring at room temperature under a nitrogen atmosphere. 10 parts by weight of powdered sodium hydroxide is added, and the external temperature of the hot plate is set to 90 ° C., followed by stirring for 30 minutes. Thereafter, 32.0 parts by weight of 2-chloroethyl vinyl ether is added dropwise over 2 hours. The stirring is continued for 4 hours while maintaining the external temperature at 90 ° C. Thereafter, 200 parts by weight of water and 300 parts by weight of methyl ethyl ketone are injected, and the mixture is washed with water until the lower alkaline aqueous layer shows neutrality. The upper methyl ethyl ketone layer was put in a desiccant, left for 6 hours, filtered, and the solvent was removed with a rotary evaporator, and diethyl vinyl ether (BIS) of 2,2-bis (4-hydroxyphenyl) hexafluoropropane was removed.
-AF-DEV) 43 parts by weight were obtained. Photoacid generator dimethoxyanthracene-2-sulfonic acid di
Synthesis of phenyliodonium salt (DIAS) 17 parts by weight of sodium 9,10-dimethoxyanthracene-2-sulfonate were dissolved in 5 parts by weight of zinc powder, and 10 parts by weight of ethanol were dissolved in 20 parts by weight of a 20% aqueous solution of sodium hydroxide at 80 ° C. 30 parts by weight of dimethyl sulfate are added dropwise. Cool to room temperature to obtain a precipitate. 2 parts by weight of the purified precipitate was added to 8 parts by weight.
A solution prepared by dissolving 2.1 parts by weight of diphenyliodonium chloride in 200 parts by weight of water at 0 ° C. and 125 parts by weight of hot water at 80 ° C. is added, and a reaction is carried out for 30 minutes. When this is cooled, white crystals of 9,10-dimethoxyanthracene-2-sulfonic acid diphenyliodonium salt are obtained. The crystals after reconsolidation, filtration and drying were 2.5 parts by weight. Preparation of Photosensitive Resin Composition 100 parts by weight of the polyimide synthesized in Example 1, 30 parts by weight of fluorine-containing vinyl ether, and 3 parts by weight of a photoacid generator DIAS were dissolved in diethylene glycol monobutyl ether and filtered with a 0.2 μm Teflon (registered trademark) filter. After filtration, a photosensitive varnish was obtained.

Evaluation of Characteristics The photosensitive varnish was spin-coated on a silicon wafer and then placed on a hot plate at 120 ° C. for 10 minutes to obtain a coating having a thickness of 3 μm. A test mask was brought into close contact with the coated film wafer and irradiated with light of 365 nm at 200 mJ.
After heating on a hot plate at 120 ° C for 10 minutes, 5
After immersing in a 2% aqueous solution of potassium hydroxide for 2 minutes, the substrate was rinsed with pure water for 30 seconds. As a result, good 20 μm L / S and via holes were observed. The photosensitive varnish was coated on a stainless steel plate and dried at 200 ° C. for 30 minutes in an oven. The dielectric constant of the film was 3.0 (1 MHZ).

Example 2 Using the apparatus of Example 1, 10.6 parts by weight of maleated methylcyclohexene tetrachloric anhydride, 7.3 parts by weight of 1,4 bis (4-aminophenoxy) benzene, 3,3 ' 3.2 parts by weight of dihydroxy-4,4'diaminobiphenyl were simultaneously charged and 10 parts by weight of a polyimide having an acid value of 85.5 synthesized in the same manner and diethyl vinyl ether BIS-
3M6CP-DEV (in the formula (1), R1: H An N-methylpyrrolidone solution containing 3 parts by weight and 0.3 parts by weight of DIAS was coated on a copper foil with a roll coater,
Prebaked in a hot air dryer at 120 ° C for 4 minutes. A test mask was brought into close contact with the coating film having a thickness of 7 μm, and irradiation was performed at 300 mJ using a 3 KW ultrahigh pressure mercury lamp. Immediately 120 ° C
And post-bake for 2 minutes in 10% potassium hydroxide solution
After immersion for minutes, it was rinsed with pure water for 30 seconds. 30 μm L /
S and via holes were observed. The photosensitive varnish was coated on a stainless steel plate and dried at 200 ° C. for 30 minutes in an oven.
(1 MHZ).

Example 3 Using the apparatus of Example 1, 10.6 parts by weight of maleated methylcyclohexenetetrachloric anhydride, 3,9-bis (3-
Aminopropyl) 5.0 parts by weight of 2,4,8,10-tetraoxaspiro [5,5] undecane and 3.4 parts by weight of diaminobenzoic acid were simultaneously charged and synthesized with 10 parts of polyimide having an acid value of 65.0. BIS-AF-DEV3 part,
An N-methylpyrrolidone solution containing 0.3 parts of DISA was coated on a copper foil with a bar coater. 120 ° C, 10
The film thickness after being left on a hot plate for 12 minutes was 12 μm. A test mask was brought into close contact with this and irradiated with 300 mJ of light at 365 nm, allowed to stand on a hot plate at 120 ° C. for 10 minutes, and then immersed in a 5% potassium hydroxide aqueous solution for 2 minutes.
An L / S of 0 μm and a via hole were obtained. This photosensitive varnish was formed into a film, and the dielectric constant was measured.
(1 MHZ).

COMPARATIVE EXAMPLE 1 When the DEV of bisphenol A was used as the diethyl vinyl ether in place of DIS-3M6C-P-DEV in the composition of Example 2, there was no inconvenience in pattern formation, but the dielectric constant was 3.3 (1 MHZ). )Met.

Comparative Example 2 In the synthesis of the polyimide of Example 3, 10.6 parts by weight of maleated methylcyclohexenetetrachloric anhydride, 3,9-
With respect to 10 parts of polyimide having an acid value of 42 consisting of 6.9 parts by weight of bis (3-aminopropyl) 2,4,8,10-tetraoxaspiro [5,5] undecane and 2.3 parts by weight of diaminobenzoic acid, BIS-AF-DEV3 part, DIS
With photosensitive polyimide having a composition of A0.3 parts, the applied film was brittle and a pattern having a contrast could not be formed by development, and the whole flowed finally.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G03F 7/029 G03F 7/029 7/037 501 7/037 501 H01L 21/027 H01L 21/30 502R F-term (reference) 2H025 AA01 AA02 AA10 AB15 AB16 AB17 AC01 AD03 BE00 BE07 BE10 CA43 CB25 CC17 FA01 FA12 4J002 CM041 EE056 EH146 EV246 EV296 FD206 GP03 4J043 PA15 PC015 PC016 PC065 PC145 PC165 QB15 QB26 RA35 SA05 SA12 TA1 UA1 UA1 UA1 UA1 UB331 UB401 UB402 VA011 VA021 VA031 VA051 VA071 VA091 VA101 YB02 YB19 YB21 ZA43 ZB22

Claims (3)

[Claims] An organic solvent-soluble polyimide containing an acid group (A), diethyl vinyl ether (B) having a structure represented by the general formula (1) and a photoacid generator (C) as essential components. In the photosensitive resin composition, the mixing ratio of each component is (B) / (A) = 10 to 60 / by weight ratio.
100, wherein (C) / (A) = 1 to 20/100. Embedded image 2. A polyimide (A) soluble in an organic solvent containing an acid group.
Wherein the acid value of the positive photosensitive resin composition is 50 to 150 (KOH mg / g). 3. An aromatic-containing diethyl vinyl ether (B).
And the ratio of ethyl vinyl ether groups is (B) /-
A positive photosensitive resin composition, wherein CH ₂ CH ₂ OCH = CH ₂ ≧ 5.2.