JP3176802B2 - Positive photosensitive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive type photosensitive resin which has a high adhesion and a pattern having a high residual film ratio during development.

[0002]

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, thinner and smaller sealing resin package, and shift to surface mounting by solder reflow. Is becoming necessary. On the other hand, as a photosensitive polyimide resin which has recently attracted attention for a technique of imparting photosensitivity to the polyimide resin itself, there is formula (3) and the like.

[0003]

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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 pollution. Therefore, recently, a positive photosensitive resin capable of developing with an aqueous alkali solution has been developed. For example, Japanese Patent Publication No. 1-46862 discloses a positive photosensitive resin composed of a polybenzoxazole resin and a diazoquinone compound. It has high heat resistance, excellent electrical properties, and fine workability, and has the potential as a resin for interlayer insulation as well as for wafer coating. Also, this positive photosensitive resin is
Since the removal of the via hole portion is performed using an alkaline aqueous solution, an organic solvent is not required for development unlike the conventional photosensitive polyimide resin, so that the safety during operation is further improved. However, since this photosensitive polybenzoxazole resin has poor adhesion to a substrate, especially a silicon wafer, it has a serious defect that the resin peels off from the substrate during development or due to moisture absorption after curing. . In addition, this photosensitive polybenzoxazole resin has a large amount of film reduction in an unexposed portion during development and has a very small time width for good development as compared with a general positive resist comprising a novolak resin and diazoquinone. Therefore, it is necessary to increase the exposure amount and develop in a short time, and there is a problem that it is difficult to use this positive photosensitive polybenzoxazole resin in an actual process.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a positive photosensitive resin having excellent adhesion and capable of obtaining a pattern having a high residual film ratio during development.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a polybenzoxazole precursor (A), a polyamic acid (B) containing a diamine having a structure represented by the general formula (1) in an amount of 30 mol% or more of the total diamine, and a polyamic acid (B). In the positive photosensitive resin composition containing the photosensitive diazoquinone (C) represented by the formula (2) as an essential component, the mixing ratio of each component is (B) /
(A) = (1-100) / 100, (C) / (A) =
(1-100) / 100 is a positive photosensitive resin composition,

[0007]

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Particularly, the acid dianhydride constituting the polyamic acid (B) is 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride and / or 4,4'-oxydiphthalic dianhydride, The photosensitive diazoquinone represented by the formula (2) is obtained by reacting 1 mol of 1,1,1-tris (4-hydroxyphenyl) ethane with 0.6 mol to 3.0 mol of 1,2-naphthoquinonediazidesulfonic acid chloride. It is an esterified product.

[0009]

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[0010]

The present invention relates to a positive photosensitive resin composition comprising a polybenzoxazole precursor, a polyamic acid and a photosensitive diazoquinone of the formula (2). The polybenzoxazole precursor of the present invention is represented by the following formula (4).

[0011]

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[0012]

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[0013]

Embedded image Note that R ₇ and R ₈ shown here may be used alone or as a mixture.

The method for producing a polybenzoxazole precursor according to the present invention comprises the steps of: condensation of a dihydroxydiamine having the structure of R ₇ with a dicarboxylic acid chloride having the structure of R ₈ ;
Alternatively, dihydroxydiamine having the structure of R ₇ and R ₈
Can be obtained by a method such as condensation in the presence of a dehydrating condensing agent such as dicyclohexylcarbodiimide. One of the features of the present invention is that a polyamic acid is an essential component together with a polybenzoxazole precursor in a photosensitive resin composition. By selecting a polymer that has excellent adhesion to the substrate as this polyamic acid, it does not impair the excellent fine workability and electrical characteristics that are the advantages of conventional polybenzoxazole resins, and it does not impair the adhesion to the substrate that was a defect The effect of improving the properties has been obtained. In order to improve the adhesion more effectively, a polyamic acid having a structure represented by the following formula (5) is desirable.

[0015]

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[0016]

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[0017]

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The diamine component having a structure represented by the general formula (1) in the polyamic acid is at least 30 mol% of the total diamine, but if it is less than 30 mol%, sufficient adhesion to the substrate cannot be obtained. The amount of the silicone-modified polyamic acid (B) containing the structure of the formula (1) is 1 to 100 parts by weight based on 100 parts by weight of the polybenzoxazole precursor (A) represented by the formula (5). Is preferred. If the amount is less than 1 part by weight, the adhesion after the humidity treatment is inferior, and if it exceeds 100 parts by weight, the film properties deteriorate. In the present invention, a part of the carboxyl group may be imidized by heating the silicone-modified polyamic acid. Another feature of the present invention is that a diazoquinone having a structure represented by the formula (2) is an essential component as a diazoquinone compound used as a photosensitive component. The diazoquinone compound in the present invention may be 1,2-naphthoquinonediazide or 1,2-naphthoquinonediazide.
A compound having 2-benzoquinonediazide; these photosensitive compounds are described in U.S. Pat.
No. 2,972, No. 2,797,213, No. 3,66,
No. 9658 and the like. That is, the diazoquinone compound itself is a substance that is hardly soluble in an aqueous alkaline solution, but generates a carboxyl group upon exposure to light and becomes easily soluble in an aqueous alkaline solution.

By utilizing this characteristic, a positive resist obtained by mixing a diazoquinone compound with a novolak resin is currently used in the field of semiconductors. When the diazoquinone compound is used together with the novolak resin, the solubility of the novolak resin is greatly reduced due to the dissolution inhibiting ability of the diazoquinone, and as a result, a good pattern with a very high residual film ratio is obtained. However, when used together with a polybenzoxazole resin as disclosed in Japanese Patent Publication No. 1-46862, a good pattern is very poor because of its lower ability to inhibit the dissolution of diazoquinone in the polybenzoxazole resin than a novolak resin. When a resin having high solubility in an aqueous alkali solution such as the polyamic acid of the present invention is used in combination, the residual film ratio after development becomes extremely poor.
The photosensitive diazoquinone represented by the formula (2) of the present invention is a known substance used in the field of positive resist as disclosed in JP-A-3-158856. When the photosensitive agent represented by the formula (2) is used for a polybenzoxazole resin, a pattern having a very high residual film ratio can be obtained. This is an effect which has not been seen in the case of a photosensitive agent comprising an esterified product of trihydroxybenzophenone and 1,2-naphthoquinonediazidesulfonic acid chloride, which has been conventionally used for a novolak resin resist.

The diazoquinone represented by the formula (2) is
Esterification is carried out by reacting 1,1-tris (4-hydroxyphenyl) ethane with 1,2-naphthoquinonediazidesulfonic acid chloride in a solvent such as tetrahydrofuran or dioxane in the presence of a basic catalyst such as triethylamine. For the ratio of 1,2-naphthoquinonediazidesulfonic acid chloride to be reacted,
1,2-Naphthoquinonediazidesulfonic acid chloride can be reacted up to 0.6 to 3.0 mol with respect to 1 mol of 1,1-tris (4-hydroxyphenyl) ethane. In the case of 0.6 mol or less, the dissolution inhibiting ability is low,
A pattern with a high residual film ratio cannot be obtained. More preferably 1,
A diazoquinone obtained by reacting 1.0 to 2.85 mol of 1,2-naphthoquinonediazidosulfonic acid chloride with respect to 1 mol of 1,1-tris (4-hydroxyphenyl) ethane. 1,2-Naphthoquinonediazide sulfonic acid chloride includes 1,2-naphthoquinonediazide-4-sulfonic acid chloride and 1,2-naphthoquinonediazide-chloride.
5-sulfonic acid chloride is preferred. For example, 1,2-naphthoquinonediazide-4 depends on the type of exposure machine used.
Sulfonic acid chloride is applied to an i-line stepper,
-Naphthoquinonediazide-5-sulfonic acid chloride is g
Although effective for a line stepper, it is not particularly limited to this and can be used.

In the present invention, polyamic acid is added in order to improve the adhesion to the substrate, but it also has the feature that the sensitivity is improved in addition to the improvement in the adhesion. That is, the photosensitive agent represented by the formula (2) exhibits extremely excellent dissolution inhibiting ability and increases the residual film ratio in the unexposed portion, but at the same time, decreases the solubility in the exposed portion. As a result, the sensitivity is reduced and the development residue is generated. However, when a polyamic acid is added as in the present invention, the solubility in an aqueous alkali solution is improved, so that an appropriate solubility is developed even in an exposed portion, and the sensitivity is improved. In the positive photosensitive resin composition of the present invention, if necessary, a leveling agent,
It is also possible to add an additive such as a silane coupling agent. The compounding amount of the photosensitive diazidoquinone compound (C) to the polybenzoxazole precursor (A) is 1 to 100 parts by weight based on 100 parts by weight of the polybenzoxazole precursor.
If the amount is less than 1 part by weight, the patterning property of the resin is poor, and if it exceeds 100 parts by weight, the tensile elongation of the film is significantly reduced. If necessary, a dihydroxypyridine derivative can be added to the positive photosensitive resin composition of the present invention in order to enhance the photosensitive characteristics.
As the dihydroxypyridine derivative, for example, 2,6-
Dimethyl-3,5-diacetyl-4- (2'-nitrophenyl) -1,4-dihydropyridine, 4- (2'-nitrophenyl) -2,6-dimethyl-3,5-dicarbethoxy-1, 4-dihydropyridine, 4- (2 ',
4'-dinitrophenyl) -2,6-dimethyl-3,5
-Carbomethoxy-1,4-dihydropyridine and the like.

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, dimethylsulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, 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.

The method of using the photosensitive resin composition of the present invention is as follows.
First, the composition is applied to a suitable support, for example, a silicon wafer, ceramic, or aluminum substrate. The application method is
Spin coating using a spinner, spray coating using a spray coater, dipping, printing, roll coating, and the like are performed. Next, after pre-baking at 60 to 120 ° 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; 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, a heat treatment is performed to form an oxazole ring,
A final pattern with high heat resistance is obtained. The 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.

Hereinafter, the present invention will be described in detail with reference to examples. Example 1 Synthesis of polybenzoxazole precursor 2,2-bis (3-amino-4-hydroxyphenyl)
73.3 parts by weight of hexafluoropropane (0.2 mol)
Was dissolved in 200 parts by weight of dried dimethylacetamide, and 39.6 parts by weight (0.5 mol) of pyridine was added thereto.
44.7 parts by weight of isophthalic acid dichloride (0.
(22 mol) was added dropwise over 30 minutes. After completion of the dropwise addition, the temperature is returned to room temperature, and stirring is continued for 5 hours under a stream of dry nitrogen. After completion of the reaction, the mixture was added dropwise to 7 liters of distilled water, and the precipitate was collected by filtration and dried under reduced pressure to obtain a polybenzoxazole precursor. Synthesis of silicone-modified polyamic acid 1,3-bis (3-aminopropyl) 1,1,3,3-
44.7 parts by weight (0.18 mol) of tetramethyldisiloxane and 61.2 parts by weight (0.19 mol) of 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride were added to N-
It was dissolved in 400 parts by weight of methyl-2-pyrrolidone and stirred at room temperature for 5 hours. The reaction solution was poured into distilled water to obtain a precipitate, which was collected by filtration and dried at 40 ° C. under vacuum. Synthesis of photosensitive diazoquinone 36.8 parts by weight (0.12 mole) of 1,1,1-tris (4-hydroxyphenyl) ethane and 72.5 parts by weight of 1,2-naphthoquinonediazide-5-sulfonic acid chloride (0 .27 mol) in 450 ml of tetrahydrofuran, and 28.3 parts by weight (0.28 mol) of triethylamine are added dropwise. After reacting at room temperature for 20 hours, the precipitated triethylamine hydrochloride was removed by filtration and poured into 10 l of ion-exchanged water to obtain a precipitate. The precipitate was collected by filtration and dried under vacuum at room temperature for 48 hours. This is designated as Photosensitive Agent (I). 100 parts by weight of a polybenzoxazole precursor prepared and synthesized from a photosensitive resin composition ,
16 parts by weight of the silicone-modified polyamic acid and 18 parts by weight of the synthesized photosensitive agent (I) were dissolved in 200 parts by weight of γ-butyrolactone, and the solution was filtered through a 0.2 μm Teflon filter.
A photosensitive varnish was obtained.

Characteristic evaluation After this photosensitive varnish was applied on a silicon wafer by using a spray coater, it was dried in an oven at 70 ° C. for 1 hour to obtain a coating film having a thickness of about 5 μm. A mask manufactured by Toppan Printing Co., Ltd. (test chart No. 1; width 0.88)
〜50.0 μm of a remaining pattern and a blanking pattern are drawn), and ultraviolet rays were irradiated at various exposure amounts using a high-pressure mercury lamp. Next, the substrate was immersed in a 0.79% aqueous solution of tetramethylammonium hydroxide for 30 seconds to dissolve and remove the exposure amount, and then rinsed with pure water for 30 seconds. As a result, the exposed portion was completely dissolved by irradiation at an exposure of 180 mJ / cm ² (the sensitivity was 180 mJ / cm ² ).
cm ² ), and a good pattern was formed. At this time, the film thickness after development was 4.3 μm, and the residual film ratio was 86.0%.
(Film thickness after development / film thickness before development × 100 = 4.3 μm /
(5.0 μm × 100 = 86.0%).
Separately, a photosensitive varnish was similarly coated on a silicon wafer, prebaked, and then placed in an oven for 30 minutes / 150 minutes.
° C, 30 minutes / 250 ° C, 30 minutes / 350 ° C,
The resin was cured. The obtained coating film was cut into 100 squares of 1 mm square, a cellophane tape was stuck and peeled off, and the coating film was to be peeled off from the silicon wafer. (Referred to as “film adhesion”) was 0, and it was confirmed that the adhesion of the cured film to the wafer was excellent.

Example 2 In the synthesis of the photosensitive diazoquinone in Example 1, 1,2-naphthoquinonediazide-5-sulfonic acid chloride was changed from 72.5 parts by weight to 32.2 parts by weight (0.12 mol) in the same manner. The operation was performed to obtain a photosensitive diazoquinone (this photosensitive agent was designated as photosensitive agent (II)). Table 1 shows the results of the same evaluation as in Example 1. Example 3 In the synthesis of the photosensitive diazoquinone in Example 1, the same operation was performed by changing 1,2-naphthoquinonediazide-5-sulfonic acid chloride from 72.5 parts by weight to 91.9 parts by weight (0.34 mol). Thus, photosensitive diazoquinone (this photosensitive agent is referred to as photosensitive agent III) was obtained. Table 1 shows the results of the same evaluation as in Example 1. Examples 4 to 5 The amount of diazoquinone added in Example 1 was changed from 18 parts by weight to 32 parts by weight (Example 4), and the amount of polyamic acid added in Example 1 was changed from 16 parts by weight to 28 parts by weight. The evaluation was carried out while changing (Example 5). Table 1 shows the results. Example 6 1,3-bis (3-aminopropyl) 1,1,3,3-diamine of the diamine constituting the polyamic acid in Example 1
The same evaluation was performed by changing 50 mol% of tetramethyldisiloxane to 4,4'-diaminodiphenyl ether. Table 1 shows the results. Example 7 The same procedure was repeated except that the 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride constituting the polyamic acid in Example 1 was changed to 4,4'-oxydiphthalic dianhydride. An evaluation was performed. Table 1 shows the results.

Comparative Example 1 In the synthesis of quinonediazide in Example 1,
1,1-tris (4-hydroxyphenyl) ethane 3
6.8 parts by weight (0.12 mol) is converted to 2,3,4-trihydroxybenzophenone 27.6 parts by weight (0.12 mol)
And the same operation was performed to synthesize a photosensitive agent IV having the following structure, and the same evaluation as in Example 1 was performed. Table 1 shows the results.

[0028]

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Comparative Example 2 In the synthesis of quinonediazide in Example 1,
1,1-tris (4-hydroxyphenyl) ethane 3
The same operation was performed by changing 6.8 parts by weight (0.12 mol) to 44.0 parts by weight (0.12 mol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, A photosensitive agent V having the following structure was synthesized and evaluated in the same manner as in Example 1. Table 1 shows the results.

[0030]

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Comparative Examples 3 and 4 The same evaluation as in Example 1 was carried out except that the addition amount of the polyamic acid was 0.5 parts by weight (Comparative Example 3) and the addition amount of diazoquinone was 0.5 parts by weight (Comparative Example 4). Was done. Table 1 shows the results
Shown in

[0032]

[Table 1]

[0033]

The resin composition of the present invention has excellent adhesion to a substrate such as a silicon wafer and can provide a pattern having a high residual film ratio during development.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-31860 (JP, A) JP-A-5-11451 (JP, A) JP-A-4-46345 (JP, A) JP-A-3-31 158856 (JP, A) JP-A-4-60548 (JP, A) JP-A-4-211255 (JP, A) JP-A-4-284454 (JP, A) JP-A-4-293050 (JP, A) JP-A-5-88362 (JP, A) JP-A-5-224411 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (2)

(57) [Claims] 1. A polybenzoxazole precursor (A),
Positive type containing, as essential components, a polyamic acid (B) containing at least 30 mol% of a diamine having a structure represented by the general formula (1) based on the total diamine and a photosensitive diazoquinone (C) represented by the general formula (2) In a photosensitive resin composition, the polyamide
The acid dianhydride constituting the acid (B) is 3,3 ′, 4,4 ′
-Benzophenonetetracarboxylic dianhydride and / or
Or 4,4'-oxydiphthalic dianhydride.
Light-sensitive diazoquinone (C) is 1,1,1-tris (4-
1,2-Naphthoki per mole of (hydroxyphenyl) ethane
2. Non-diazide sulfonic acid chloride is added in an amount of 0.6 mol to 3.
It is an esterified product obtained by reacting 0 mol, and the mixing ratio of each component is (B) / (A) = (1-100) / 1 by weight ratio.
00, (C) / (A) = (1-100) / 100, wherein the positive photosensitive resin composition is characterized in that: Embedded image Embedded image 2. The method of claim 1, wherein the 1,2-naphthoquinonediazidesulfonic acid chloride is 1,2-naphthoquinonediazide-4-sulfonic acid chloride or 1,2-naphthoquinonediazide-5.
- positive photosensitive resin composition of claim 1 wherein the acid chloride.