JP3449931B2 - Positive photosensitive resin composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive type having a high residual film ratio at the time of development and having extremely excellent mechanical properties as a protective film and an interlayer insulating film. The present invention relates to a photosensitive resin composition. 2. Description of the Related Art Conventionally, a polyimide resin having excellent heat resistance and excellent electrical and mechanical properties has been used for a surface protective film and an interlayer insulating film of a semiconductor element. There is a demand for remarkable improvement in heat cycle resistance and heat shock resistance due to high integration, large size of devices, thinning and miniaturization of encapsulation resin package, transition to surface mounting by solder reflow, etc. Polyimide resins have become necessary. On the other hand, a technique of imparting photosensitivity to the polyimide resin itself has recently attracted attention. For example, the following formula (III) and the like are examples of the photosensitive polyimide resin. [0003] When this is used, a part of the pattern forming process can be simplified, which has the effect of shortening the process.
Since a solvent such as methyl-2-pyrrolidone is required, there is a problem in safety and handling. Therefore, recently, a positive photosensitive resin that can be developed with an alkaline aqueous solution has been developed. For example, Japanese Patent Publication No. 1-46862 discloses a positive photosensitive resin composition comprising a polybenzoxazole precursor and a naphthoquinonediazide compound. It has high heat resistance, excellent electrical properties, and fine workability, and has the potential not only for wafer coating but also for interlayer insulation. The mechanism of development of this positive photosensitive resin is that the naphthoquinonediazide compound in the unexposed portion is insoluble in an alkaline aqueous solution, undergoes a chemical change upon exposure, and becomes soluble in an alkaline aqueous solution. By utilizing the difference in solubility between the exposed part and the unexposed part, a coating film pattern can be formed only in the unexposed part. However, the positive photosensitive resin composition disclosed in Japanese Patent Publication No. 1-46862 has low sensitivity, poor storage stability, and has a problem in practicality. Therefore, Japanese Patent Publication No. 6-60140 discloses a positive type photosensitive resin composition containing a polybenzoxazole precursor as a base resin, which also has improved disadvantages thereof. Here, hexafluoro-2,2-bis (3-amino-4-hydroxyphenyl) -propane is characterized as the diamine of the polybenzoxazole precursor. With this hexafluoroisopropylidene group,
Photospeed, solubility in organic solvents, adhesion, storage stability and resolution are improved. [0005] A semiconductor package often used in current memories and the like is called a LOC (lead-on-chip) structure. In manufacturing the LOC package, a lead frame provided with an adhesive is pressed on a chip. Therefore, it is indispensable to cover the surface of the chip with a surface coating material such as polyimide. However, if the mechanical properties of the surface coating material are poor, the impact often causes cracks in the surface coating material when the lead frame is pressed. For these reasons, surface coating materials for LOC require higher mechanical properties. However, polybenzoxazole comprising isophthalic acid chloride, terephthalic acid chloride and hexafluoro-2,2-bis (3-amino-4-hydroxyphenyl) -propane described in the examples of JP-B-6-60140. Unfortunately, the precursor does not have mechanical properties that can accommodate this LOC structure. In order to improve the mechanical properties by increasing the molecular weight, if the reaction is carried out by changing the molar ratio of the acid to the amine at the time of the reaction, the molecular weight will be increased under a slightly excessive acid condition. However, the synthesis method using acid chloride has high reactivity and there is no reaction selection system. Therefore, when the reaction is performed with an excess of acid, the reaction proceeds to a hydroxyl group, and gelation often occurs during the reaction, and the entire reaction flask is solidified. Even if the reaction is completed without solidification of the entire reaction flask, fine gel-like substances are found in the reaction mixture after the reaction, which causes clogging of filtration performed later. Japanese Patent Application Laid-Open No. 9-183846 discloses a method of synthesizing a polybenzoxazole precursor using 1-hydroxybenzotriazole. When synthesized by this method, the above-mentioned problem of gelation that occurs during the synthesis by the acid chloride method can be solved brilliantly.
Further, in that embodiment, diphenyl ether-4,4 '
-Dicarboxylic acid and diester composed of 1-hydroxybenzotriazole are reacted with hexafluoro-2,2-bis (3-amino-4-hydroxyphenyl) -propane to terminate in 5-norbornene-2,3-dicarboxylic acid An anhydride end-capped polybenzoxazole precursor is shown. The mechanical properties of a cured film of a polybenzoxazole precursor using diphenyl ether-4,4'-dicarboxylic acid as the acid component are as follows: isophthalic chloride, terephthalic chloride and hexafluoro-
2,2-bis (3-amino-4-hydroxyphenyl)
Significantly improved compared to the polybenzoxazole precursor consisting of propane. However, when a naphthoquinodiazide compound as a photosensitizer is added to this polybenzoxazole precursor to sensitize it to form a positive photosensitive resin composition, the mechanical properties of the cured film are the mechanical properties of only the polybenzoxazole precursor. Lower than the characteristics. This is nothing but the fact that the naphthoquinodiazide compound remains in the film even after curing and lowers the mechanical properties. Therefore, in order to obtain high mechanical properties, it is necessary to reduce the addition amount of the naphthoquinodiazide compound as much as possible, or to select a naphthoquinodiazide compound that does not degrade the cured film properties even if it remains, but a satisfactory one is obtained. It is not currently done. SUMMARY OF THE INVENTION The present invention provides a positive photosensitive resin composition which has a high residual film ratio during development and has extremely excellent mechanical properties as a protective film and an interlayer insulating film. Is to provide. The present invention provides a resin composition comprising a polybenzoxazole precursor represented by the formula (I) and a naphthoquinonediazide compound represented by the formula (II).
And a naphthoquinodiazide compound represented by the formula (II)
Is a polybenzoxazole represented by the formula (I)
A positive photosensitive resin composition characterized by being 1 to 30 parts by weight based on 100 parts by weight of a precursor . [0009] [0010] The polybenzoxazole precursor represented by the formula (I) is disclosed in JP-A-9-183846. Although this polybenzoxazole resin is used with diphenyl ether-4,4'-dicarboxylic acid having a flexible ether bond in the acid component, it has excellent mechanical properties. It has been found that the addition of the naphthoquinonediazide compound represented by the formula (II) gives excellent mechanical properties even after photosensitization without deteriorating the mechanical properties. The naphthoquinonediazide compound of the formula (II) is disclosed in Japanese Patent Application Laid-Open Nos.
It is a photosensitive agent widely used in the field of positive resists as disclosed in Japanese Patent No. 98749. JP-A-7-281441 is a compound which reports that a high residual film ratio can be obtained at the time of development when this photosensitizer is used simultaneously with a polybenzoxazole precursor. In the present invention, it has been found that when this known photosensitizer is further combined with a polybenzoxazole precursor having a limited composition structure represented by the formula (I), the mechanical properties of a cured film which are unexpectedly improved are improved. It is a thing. The manifestation of this effect is that the ballast compound of the naphthoquinonediazide compound of the formula (II) interacts with the flexible structure possessed by the ballast compound itself and at the time of curing with the terminal unsaturated portion of the polybenzoxazole precursor of the formula (I). It is thought to be a synergistic effect, but details are unknown. Further, the naphthoquinonediazide compound of the formula (II) can obtain a high residual film ratio at the time of development with an addition amount of 30 parts by weight or less based on 100 parts by weight of the polybenzoxazole precursor. Therefore, the amount remaining in the film is small, and as a result, the mechanical properties are excellent. This is because the photosensitizers conventionally used, which consist of trihydroxybenzophenone and naphthoquinonediazite, require a considerably large amount of addition to obtain a high residual film ratio during development. However, the amount remaining after curing becomes large and the mechanical properties are low. DETAILED DESCRIPTION OF THE INVENTION The polybenzoxazole precursor of the formula (I) is a hexafluoro-2,2
-Bis (3-amino-4-hydroxyphenyl) -propane and diphenyl ether-4,4 'having the structure of Y
When the polybenzoxazole precursor is heated at about 300 to 400 ° C., the ring is closed and changes to a heat-resistant resin called polybenzoxazole. In the production, diphenyl ether-4,4 '
After synthesizing an active ester derivative from dicarboxylic acid and 1-hydroxybenzotriazole at one end, it is reacted with hexafluoro-2,2-bis (3-amino-4-hydroxyphenyl) -propane. The compounding amount of the naphthoquinonediazide compound (B) to the polybenzoxazole precursor (A) is preferably 1 to 30 parts by weight with respect to 100 parts by weight of the polyamide. Is poor in patterning property, and conversely, if it exceeds 30 parts by weight, the sensitivity is significantly reduced. If necessary, additives such as a leveling agent and a silane coupling agent can be added to the positive photosensitive resin composition of the present invention. In the present invention, these components are dissolved in a solvent and used in the form of a varnish.
Examples of the solvent include N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylacetamide, dimethyl sulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and propylene glycol. Monomethyl ether acetate, methyl lactate, ethyl lactate, butyl lactate, methyl-1,3-butylene glycol acetate, 1,3
-Butylene glycol-3-monomethyl ether, methyl pyruvate, ethyl pyruvate, methyl-3-methoxypropionate and the like may be used alone or in combination. In the method of using the positive photosensitive resin composition of the present invention, the composition is first applied to a suitable support, for example, a silicon wafer, ceramic, aluminum substrate or the like. Examples of the coating method include spin coating using a spinner, spray coating using a spray coater, dipping, printing, and roll coating. Next, after pre-baking at 60 to 130 ° C. to dry the coating film, a desired pattern shape is irradiated with actinic radiation. As the actinic radiation, X-rays, electron beams, ultraviolet rays, visible rays and the like can be used, but those having a wavelength of 200 to 500 nm are preferable. Next, a relief pattern is obtained by dissolving and removing the irradiated portion with a developer. Examples of the developer include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, and di-n. Secondary amines such as propylamine, tertiary amines such as triethylamine and methyldiethylamine, alcoholamines such as dimethylethanolamine and triethanolamine, and quaternary ammoniums such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. An aqueous solution of an alkali such as a salt or an aqueous solution obtained by adding a suitable amount of a water-soluble organic solvent such as an alcohol such as methanol or ethanol or a surfactant thereto can be suitably used. As a developing method, a system such as spray, paddle, immersion, and ultrasonic wave can be used. Next, the relief pattern formed by development is rinsed. Distilled water is used as the rinsing liquid. Next, heat treatment is performed to form an oxazole ring, and a final pattern having high heat resistance is obtained. The positive photosensitive resin composition according to the present invention is useful not only for semiconductor applications but also as interlayer insulation for multilayer circuits, cover coats for flexible copper clad boards, solder resist films, liquid crystal alignment films, and the like. The present invention will be described below in detail with reference to examples. << Example 1 >> * Synthesis of polybenzoxazole precursor 443.2 g (0.93) of a dicarboxylic acid derivative obtained by reacting 1 mol of diphenyl ether-4,4'-dicarboxylic acid with 2 mol of 1-hydroxybenzotriazole. Mol) and hexafluoro-2,2-bis (3-amino-4
-Hydroxyphenyl) propane 366.3 g (1.0
Mol) was placed in a four-neck separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube.
3000 g of -methyl-2-pyrrolidone was added and dissolved. Thereafter, the reaction was carried out at 75 ° C. for 12 hours using an oil bath. Next, 32.8 g (0.2 mol) of 5-norbornene-2,3-dicarboxylic anhydride dissolved in 500 g of N-methyl-2-pyrrolidone was added, and the mixture was further stirred for 12 hours to complete the reaction. After the reaction mixture was filtered, it was poured into a solution of water / methanol = 3/1, the precipitate was collected by filtration, washed sufficiently with water, dried under vacuum, and dried to obtain the desired polybenzoxazole precursor (A-1). ) Got. Preparation of Positive Photosensitive Resin Composition Polybenzoxazole precursor (A-1) 10 synthesized
0 g of a naphthoquinonediazide (B
-1) After dissolving in 25 g and N-methyl-2-pyrrolidone 250 g, the solution was filtered through a 0.2 μm Teflon filter to obtain a photosensitive resin composition. Embedded image * Characteristic evaluation After coating this positive photosensitive resin composition on a silicon wafer using a spin coater, it was dried on a hot plate at 120 ° C. for 4 minutes to obtain a coating film having a thickness of about 5 μm. . G-line stepper exposure machine NSR-1505G3A
(Manufactured by Nikon Corporation) through a reticle, 50 mJ /
Increase from cm ² 20mJ / cm ² at a time 540mJ / c
Exposure was performed up to m ² . Next, the exposed portion was dissolved and removed by immersion in a 1.4% tetramethylammonium hydroxide aqueous solution for 60 seconds, and then rinsed with pure water for 30 seconds. As a result, it was confirmed that a pattern was formed from a portion irradiated with an exposure amount of 350 mJ / cm ² (sensitivity of 350 mJ / cm ² ). At this time, the residual film ratio (film thickness after development / film thickness before development × 100) was 96%. Further, the positive photosensitive resin composition was applied on a silicon wafer using a spin coater, and then dried on a hot plate at 120 ° C. for 6 minutes to obtain a coating having a thickness of about 15 μm. This coating was applied to a PLA-6 manufactured by Canon using a 10 mm strip-shaped pattern photomask.
It was exposed at 00. Next, the exposed portion was dissolved and removed by immersion in a 1.4% aqueous solution of tetramethylammonium hydroxide, and then rinsed with pure water for 30 seconds. 150 ℃ / 30min + 250 ℃ / 30min + 350 ℃ /
Curing was performed under a nitrogen atmosphere under the conditions of 30 minutes. Next 3
% Hydrofluoric acid aqueous solution, peel off the strip film,
After sufficiently washing with pure water and drying, a strip test sample was obtained. This film was pulled with Tensilon to evaluate mechanical properties. Table 1 shows the results. Example 2 In the preparation of the positive photosensitive resin composition in Example 1, naphthoquinonediazide (B
A positive photosensitive resin composition was prepared in which the addition amount of -1) was reduced to 10 g, and the same evaluation as in Example 1 was performed. Table 1 shows the results
Shown in Comparative Example 1 In the synthesis of the polybenzoxazole precursor of Example 1, diphenyl ether-4,
Instead of the dicarboxylic acid derivative obtained by reacting 4'-dicarboxylic acid with 2 mol of 1-hydroxybenzotriazole, 0.5 mol of isophthalic acid and 0.5 mol of terephthalic acid are used instead of the dicarboxylic acid derivative.
A polybenzoxazole precursor (A-2) was synthesized using a dicarboxylic acid derivative obtained by reacting 5 mol with 2 mol of 1-hydroxybenzotriazole. Next, the same evaluation as in Example 1 was performed. The results are shown in Table 1. Comparative Example 2 In the synthesis of the polybenzoxazole precursor of Example 1, 5-norbornene-2,3
-The same operation was performed thereafter without adding the dicarboxylic anhydride to synthesize the polybenzoxazole precursor (A-3). Next, the same evaluation as in Example 1 was performed.
The results are shown in Table 1. Comparative Example 3 In the preparation of the positive photosensitive resin composition of Example 1, naphthoquinonediazide (B-1)
Instead of naphthoquinonediazide (B-2)
The same evaluation as in Example 1 was performed using Table 1 shows the results. Embedded image [Table 1] According to the present invention, it is possible to obtain a positive photosensitive resin composition having a high residual film ratio during development and having extremely excellent mechanical properties as a protective film and an interlayer insulating film. Can be.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-123034 (JP, A) JP-A-7-281441 (JP, A) JP-A-9-146273 (JP, A) JP-A-9-99 183848 (JP, A) JP-A-8-269198 (JP, A) JP-A-5-197153 (JP, A) JP-A-11-109620 (JP, A) JP-A-11-143070 (JP, A) JP-A-11-10069 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (1)

(57) [Claim 1] A resin composition comprising a polybenzoxazole precursor represented by the formula (I) and a naphthoquinonediazide compound represented by the formula (II), Indicated by
The addition amount of the naphthoquinodiazide compound is represented by the formula (I).
100 parts by weight of polybenzoxazole precursor
A positive photosensitive resin composition, wherein the composition is 1 to 30 parts by weight . Embedded image Embedded image