JP2586046B2 - Photosensitive polyimide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] In recent years, the use of polyimide resin has been active in the field of semiconductor industry and high-density printed wiring board industry. In particular, polyimide-based resins have attracted attention because of their ability to perform pattern processing in addition to the heat resistance of polyimide, but conventionally known resins do not always have sufficient operation performance.

The present invention relates to a photosensitive polyimide which has sufficient photosensitivity as a material in the industrial field, enables formation of a fine pattern, and has excellent solubility in an organic solvent.

[Conventional technology]

Conventionally, there have been many reports of polyimide-based photosensitive resins, and most of them have been described as compositions containing a photosensitive compound mixed with a non-photosensitive polyamic acid (for example, see JP-A-48-8900).
4, 49-74739, and 56-93704), wherein a photosensitive group is added to a polymer side chain of polyamic acid (for example,
JP-A Nos. 54-116216, 54-145794, 55-9510, and 55-
9538, 57-143329).

However, since these are all polyamic acids or their adducts, they require imidization by heating and curing at a high temperature during pattern processing, and have the drawback that they cannot be used if the solid state element or the substrate cannot withstand the curing temperature. . Furthermore, during heating and curing, a photosensitive compound or a photosensitive group is scattered, so that a disadvantage that shrinkage after curing is remarkable and a large dimension reduction is inevitable.

In order to improve the above-mentioned drawbacks, photosensitive polyimide soluble in an organic solvent which does not require high-temperature heat curing has been proposed, and has been proposed in JP-A-57-131227 and JP-A-59-145216. However, the photosensitivity of the former is about 5 J / cm ^2, the latter is a 3.5 J / cm ^2, was not any satisfactory.
In addition, according to the study of the present inventors, they have a problem that they have insufficient solubility and require a long time phenomenon.

[Problems to be solved by the present invention]

In view of the above-mentioned situation, the present inventors have a photosensitive group in the polymer main chain, have excellent heat resistance, excellent electrical and mechanical properties, and have a sufficiently high solubility in an organic solvent. As a result of diligent research for the purpose of the development of a polymer, we have succeeded in obtaining a photosensitive polyimide resin that satisfies the problem.

[Means for solving the problem]

Thus, the present invention provides a compound represented by the general formula [I]: (Wherein X is the same or different and represents a halogen atom or a nitro group, and m represents an integer of 4 or less).
The present invention relates to a photosensitive polyimide having a viscosity of 100 centipoise or more in pyrrolidone at a concentration of 20% by weight and a temperature of 25 ° C.

That is, the photosensitive polyimide of the present invention is a specific carboxylic acid, 5- (2,5-dioxotetrahydrofuryl)-.
3-methyl-3-cyclohexene-1,2-dicarboxylic acid or a dianhydride thereof (hereinafter abbreviated as MCTC) and a novel photosensitive aromatic diamine compound represented by the following formula [IIa] (hereinafter simply referred to as [II a)) and a polyamic acid obtained by polymerizing the resulting polyamic acid with dehydration ring closure (imidization), or
It can be synthesized by a method of decarboxylating a polyimide precursor obtained by polymerizing MCTC and a diisocyanate compound of [IIa] represented by the general formula [IIb] (hereinafter simply referred to as [IIb]).

(In the formula, R ₁ , R ₂ , X and m are the same as those in the general formula [I].) Specific examples of [IIa] and [IIb] include the following. It is not limited.

More specifically, the above MCTC and (IIa) or (IIb) are polymerized in an organic solvent at a reaction temperature of 0 to 200 ° C., preferably 15 to 160 ° C. for 1 to 48 hours, and then the obtained polyimide An imidizing agent such as acetic anhydride, pyridine, or a tertiary amine is added to the precursor, and the imidization reaction is performed at a reaction temperature of 160 ° C. or lower, preferably 100 ° C. or lower for 30 minutes to 8 hours, preferably 2 to 4 hours. By doing so, the photosensitive polyimide of the present invention is synthesized.

Examples of the organic solvent that can be used in the polymerization reaction and the imidation reaction include, for example, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N
-Diethylacetamide, N, N-dimethylmethoxyacetamide, N-methylcaprolactara, dimethylsulfoxide, N-methyl-2-pyrrolidone, dimethylsulfone, hexamethylphosphamide, tetramethylsulfone, N-acetyl-2-pyrrolidone , Phenol, cresol, xylenol, quinoline, pyridine and the like, and these may be a mixture of two or more. In the practice of the present invention, if necessary, two or more of [IIa] or [IIb] may be used in combination,
It is preferably equimolar to MCTC.

The concentration of the polymer in the polymerization reaction and the imide compound is 60% by weight or less, preferably 40% by weight or less.

When the photosensitive polyimide of the present invention is used in a state of being dissolved in an organic solvent, the concentration of the polymer is preferably 5 to 40% by weight.

The obtained photosensitive polyimide may be used alone or several types of sensitizers such as photopolymerization initiators such as acrylate-based, methacrylate-based photopolymerizable compounds, bisazide-based photopolymerizable compounds, Michler's ketone, and benzoin as needed. It is also possible to add.

[Action and effect of the invention]

The photosensitive polyimide thus obtained can easily form a relief pattern by photochemical means,
The formed relief pattern has excellent heat resistance, electrical and mechanical properties even without performing a high-temperature and long-time curing process. It is useful as a film, an α-ray protective film, an etching resist film, a plating protective film, an insulating film for multilayer wiring of a hybrid circuit or a printed circuit, or a solder resist. In addition, it can be used as a heat-resistant photosensitive film, a separation film, or an alignment film for liquid crystal.

Hereinafter, the present invention will be described in more detail with reference to Synthesis Examples and Examples. In the examples, the viscosity is a viscosity measured in N-methyl-2-pyrrolidone at a concentration of 20% by weight and a temperature of 25 ° C.

(Synthesis Examples and Examples)

Synthesis Example 1 First, 1,4-bis [2-
(3-aminobenzoyl) ethenyl] benzene (hereinafter, referred to as
mp-BAEB).

17.6 g of m-aminoacetophenone and 6.7 g of terephthalaldehyde were placed in a separable flask having a capacity of 300 ml, the air in the flask was replaced with nitrogen, and then 100 ml of acetic acid was added. Next, the mixture was heated while stirring, and when the liquid temperature reached 80 ° C., 4.6 ml of an 85% orthophosphoric acid aqueous solution was added, and the stirring reaction was continued for about 30 minutes. The precipitated product was collected, washed with water, methanol, and ether, and then dried in a vacuum dryer.
19.2 g of m.p-BAEB phosphate were obtained.

Next, about 400 ml of N, N- was added to the obtained mp-BAEB phosphate.
Dimethylacetamide was added and dissolved, and neutralized with a 15% aqueous sodium carbonate solution. After the neutralization was completed, the precipitated inorganic salt was separately removed, and the solution was poured into water to precipitate a yellow solid. A yellow solid was collected and dried, and then recrystallized from pyridine to obtain 11.5 g of mp-BAEB. (Yield 62.2%) Synthesis Example 2 Using p-aminoacetophenone instead of m-aminoacetophenone as a starting material and isophthalaldehyde as a raw material instead of terephthalaldehyde, 1,3- Bis [2- (4-aminobenzoyl) ethenyl] benzene (hereinafter abbreviated as “pmm-BAEB”) was synthesized. (Yield 56.8%) Synthesis Example 3 Nitroterephthalaldehyde was used as a raw material instead of terephthalaldehyde, and the same method as in Synthesis Example 1 was used.
1,4-bis [2- (3-aminobenzoyl) ethenyl]
Nitrobenzene (hereinafter abbreviated as NO ₂ -BAEB) was synthesized. (Yield: 45.5%) Example 1 10.0 g of mp-BAEB was placed in a 200 ml separable flask, and the air in the vessel was replaced with dry nitrogen, followed by dehydration distillation of N.
69 g of -methyl-2-pyrrolidone was added and dissolved by stirring.
In this, MC which underwent recrystallization treatment with acetic anhydride
After adding 7.2 g of TC, the temperature was raised to 120 ° C., and a stirring reaction was performed under a nitrogen atmosphere for 4 hours. When a part of the polyamic acid obtained after cooling to room temperature was sampled and the infrared absorption spectrum of the film was measured, no characteristic absorption of the imidized product was observed.

Next, 10 g of pyridine and 20 g of acetic anhydride were added to 65 g of the above polyamic acid solution, and an imidization reaction was performed at 50 ° C. for 2 hours. After the completion of the reaction, the solution was poured into acetone 1 to precipitate a polyimide. After being sufficiently stirred and washed with acetone, it was dried separately to obtain 14 g of a yellow polyimide resin.

The synthesized polyimide resin was redissolved in N-methyl-2-pyrrolidone so as to be 20% by weight to obtain a polyimide varnish. The viscosity was 2500 centipoise. A film was prepared from this varnish and the infrared absorption spectrum was measured. As shown in FIG. ¹ , the film was 1,770 cm ⁻¹ , 1,380 cm
^{At -1} , the characteristic absorption peak of the imidized compound was observed.

Spin coat a polyimide varnish on a glass plate,
By prebaking at 80 ° C. for 1 hour, a film having a thickness of 5 μm was formed. A pattern mask film (Dai Nippon Printing Test Chart) is adhered to the film, and irradiated with light from a 500 W ultra-high pressure mercury lamp at 200 mJ / cm ² , followed by mixing of N-methyl-2-pyrrolidone and isopropyl alcohol 4: 1. When developed with a solvent, a clear negative type pattern in which the exposed portions were cured was obtained.

When the heat resistance of this polyimide was measured in a nitrogen atmosphere by thermogravimetric analysis, no weight loss was observed up to 320 ° C.

The elemental analysis values and the structure of the photosensitive polyimide synthesized in Example 1 are shown below.

Elemental analysis value; C: 73.2% (theoretical value 74.4%) H: 4.98% (theoretical value 4.73%) N: 4.20% (theoretical value 4.70%) Example 2 A photosensitive polyimide represented by the following formula was synthesized in the same manner as in Example 1, except that pm-BAEB obtained in Synthesis Example 2 was used instead of mp-BAEB. The same photosensitive test as in Example 1 was performed using N-methyl-2-pyrrolidone varnish (viscosity: 1500 centipoise) having a concentration of 20% by weight of this photosensitive polyimide, and the exposed portion was exposed at an exposure amount of 240 mJ / cm ² . A hardened negative type clear pattern could be obtained.

Next, when the heat resistance of this polyimide was measured, no weight loss was observed up to 320 ° C. in a nitrogen atmosphere.

The elemental analysis values and the structure of the photosensitive polyimide synthesized in Example 2 are shown below.

Elemental analysis value; C: 73.6% (theoretical value 74.5%) H: 4.94% (theoretical value 4.73%) N: 4.26% (theoretical value 4.70%) Example 3 A photosensitive polyimide represented by the following formula was synthesized in the same manner as in Example 1 except that NO ₂ -BAEB obtained in Synthesis Example 3 was used instead of m · p-BAEB.

20% by weight of N-methyl-
Using 2-pyrrolidone varnish (viscosity: 1200 centipoise), the same light-sensitive test as in Example 1 was performed, and the result was 500 mJ / cm.
^At a light exposure of ² , a clear negative pattern having a hardened exposed portion was obtained.

When the heat resistance of this polyimide was measured, no weight loss was observed up to 320 ° C. in a nitrogen atmosphere.

The structure of the elemental analysis value of the photosensitive polyimide synthesized in Example 3 is shown below.

Elemental analysis; C: 66.9% (theoretical 69.3%) H: 4.88% (theoretical 4.24%) N: 6.14% (theoretical 6.55%)

[Brief description of the drawings]

FIG. 1 is a chart of an infrared absorption spectrum of the polyimide resin obtained in Example 1.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Noriaki Honda Inventor 6-1-1 Shinjuku, Katsushika-ku, Tokyo Mitsubishi Gas Chemical Co., Ltd.

Claims (2)

(57) [Claims] 1. The following general formula [I] (Wherein X is the same or different and represents a halogen atom or a nitro group, and m represents an integer of 4 or less).
A photosensitive polyimide having a viscosity of 100 centipoise or more in pyrrolidone at a concentration of 20% by weight and a temperature of 25 ° C. 2. The photosensitive polyimide according to claim 1, wherein X is a nitro group and m is an integer of 3 or less.