JPH0683054A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To obtain a photosensitive resin excellent in adhesion property with a semiconductor element and an epoxy sealing material and showing no deterioration after moisture absorption treatment by using a specified polyamide acid ester as the main component. CONSTITUTION:A polyamide acid ester expressed by formula I is used as the main component. In formula I, R1, R2, R3 and R4 are expressed by formula II, III, IV, and V, respectively, and R5 is a 2- or 4-valent org. group, R6 is H or CH3, R1, R2, R5, R6 are independent and may be same or different, x-z represent mol% of each structural unit satisfying 0<x, y<100, 0<z<80 and x+y+z=100, p is an integer 1-3, [R2] and [R4] represents percentages of structural units, R3 and R4, respectively, satisfying [R3]+[R4]=100 and 0.2<[R3]/[R4]<2. The polyamide acid ester expressed by formula I has high sensitivity and excellent adhesion property with a semiconductor element and an epoxy sealing material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a photosensitive resin composition which retains excellent photosensitivity and has a cured film excellent in adhesion to a semiconductor element and a sealing resin.

[0002]

2. Description of the Related Art Conventionally, surface protection films, interlayer insulating films, etc. of semiconductor elements have excellent heat resistance and excellent electrical characteristics.
Polyimide, which has mechanical properties, is used,
In recent years, due to the high integration of semiconductor elements, large size, thinning and miniaturization of encapsulation resin package, and transition to surface mounting method by solder reflow, there has been a demand for remarkable improvement in heat cycle resistance, heat shock resistance, etc. High performance polyimide resins have been required. On the other hand, a technique of imparting photosensitivity to the polyimide resin itself has recently attracted attention. The use of these photosensitized polyimide resins not only has the effect of simplifying the pattern creation process compared to non-added polyimide resins, but it also saves the use of highly toxic etching liquids, so it is safe. It is also excellent in terms of pollution, and it is expected that photosensitization of polyimide resin will be an important technology. As the photosensitive polyimide resin, for example, the following formula (A)

[0003]

[Chemical 3]

A polyimide precursor composition having a photosensitive group with an ester group having a structure as shown in (for example, JP-B-55-41422, JP-A-60-228537) or the following formula (B)

[0005]

[Chemical 4]

A composition obtained by adding a compound containing a carbon-carbon double bond and an amino group or a quaternized salt thereof, which is dimerized or actinically exposed to actinic radiation, to a polyamic acid having the structure shown in (for example, JP-A-59-52822) and the like are known. All of these are dissolved in an appropriate organic solvent, applied in a varnish state, dried, irradiated with ultraviolet rays through a photomask, developed and rinsed to obtain a desired pattern, and further subjected to heat treatment to form a polyimide. It is a film. However, although such a conventional technique has excellent photosensitivity and good adhesion to a substrate such as Si, it has a problem of low adhesion to an epoxy-based encapsulating material.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive resin which is excellent in adhesiveness between a semiconductor element and an epoxy type encapsulating material and which is not deteriorated after a moisture absorption treatment.

[0008]

The present invention is a photosensitive resin composition containing a polyamic acid ester represented by the formula (1) as a main component.

[0009]

[Chemical 5]

[0010]

[Chemical 6]

[0011]

The polyamic acid ester represented by the formula (1) used in the present invention is characterized by having high sensitivity and excellent adhesiveness with the semiconductor element and the epoxy-based encapsulating material. In formula (1), R ₁ is introduced from a compound having a tetravalent organic group, and pyromellitic dianhydride,
3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride or derivatives thereof are used. In addition, one kind or a mixture of two or more kinds may be used.

In the formula (1), R ₂ is introduced from a compound having a divalent organic group and includes 4,4'-diaminodiphenyl ether and 2,2-bis [4- (4-aminophenoxy) phenyl. ] Propane or derivatives thereof are used. Also, the molar percentage of the structural units of 4,4'-diaminodiphenyl ether [R _21], 2,2-bis [4
- (4-aminophenoxy) when the molar percentage of the structural units of the phenyl] propane and [R _22] [R _21] +
[R ₂₂ ] = 100 and 4> [R ₂₁ ] / [R ₂₂ ] ≧ 0. When 4 ≦ [R ₂₁ ] / [R ₂₂ ], the adhesion of the epoxy-based encapsulating material and Si to the substrate or the like is low, which is not preferable. More preferably 2> [R ₂₁ ] / [R ₂₂ ]> 0.5
Is.

In the formula (1), R ₃ is a photosensitive group having 1 to 3 acrylic (methacryl) groups. When the acryl (methacryl) group is 0, a crosslinked structure cannot be obtained, which is not preferable. Further, four or more acrylic (methacrylic) groups are not preferable because they deepen the coloring after curing. Examples of the compound for introducing R ₃ include pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol acrylate dimethacrylate, pentaerythritol diacrylate methacrylate, glycerol diacrylate, glycerol dimethacrylate, glycerol acrylate methacrylate, trimethylol. Propane diacrylate, 1,3-
Diacryloylethyl-5-hydroxyethyl isocyanurate, 1,3-dimethacrylate-5-hydroxyethyl isocyanurate, ethylene glycol modified pentaerythritol triacrylate, propylene glycol modified pentaerythritol triacrylate, trimethylolpropane diacrylate, trimethylolpropane Dimethacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, glycidyl methacrylate, glycidyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, polyethylene glycol modified methacrylate, polyethylene glycol modified acrylate,
Examples thereof include, but are not limited to, polypropylene glycol-modified acrylate and polypropylene glycol-modified methacrylate. In using these, one kind or a mixture of two or more kinds may be used.

In the formula (1), R ₄ is --CH ₃ group or --C ₂
H ₅ group. These esters are characterized by low coloring due to the high volatility of methyl groups and ethyl groups in the cured product. -C ₂ H ₅ group or propyl group, a butyl group or the like is not preferable because with colored darker the reactivity with the carboxyl groups decreases. Further, the ratio of the structural units of the photosensitive groups R ₃ and R ₄ is [R ₃ ] + [R ₄ ] = 10, where the molar percentages are [R ₃ ], [R ₄ ].
0 and 0.2 <[R ₃ ] / [R ₄ ] <2. When it is 0.2 or less, the photosensitivity is deteriorated, which is not preferable. When it is 2 or more, the degree of coloring of the cured film increases, which is not preferable.

In the polyamic acid ester represented by the formula (1), the proportion of structural units having a photosensitive group introduced into a carboxyl group is X, the proportion of structural units having a photosensitive group partially introduced is Y, and a carboxyl group is a carboxyl group. The ratio of the structural units having the CH ₃ group or C ₂ H ₅ group introduced is Z, and three types of structural units are mixed. 0 <X, Y <100, 0 respectively
<Z <80 and X + Y + Z = 100 are satisfied, and X, Y, and Z represent the mole percentage of each structural unit. When Z is 80 or more, the amount of the photosensitive group is small, the sensitivity is low and the practicality is low.

The polyamic acid ester (1) in the present invention is usually synthesized as follows. First, a compound having an alcohol group for introducing the photosensitive groups R ₃ and R ₄ is dissolved in a solvent, and an excess acid anhydride or its derivative is reacted with this. After that, the remaining carboxyl group and acid anhydride group can be reacted with diamine to synthesize. That is, by controlling the reaction molar ratio of the R ₃ component and R ₄ component, the acid anhydride component, and the diamine component, the molar ratio of R ₃ and R ₄ and the molecular weight can be easily controlled. In the present invention, a sensitizer, an initiator, a storability improver and the like may be added to improve lithographic properties such as sensitivity and resolution. As a sensitizer,

[0017]

[Chemical 7]

[0018]

[Chemical 8]

Although not limited thereto, the present invention is not limited thereto. In addition, one kind or a mixture of two or more kinds may be used. The amount of the sensitizer added is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the polyamic acid ester. If it is 0.1 part by weight or less, the amount of addition is too small and it is difficult to obtain the effect of improving sensitivity. If it is 10 parts by weight or more, the strength of the cured film is lowered, which is not preferable.

Further, as an initiator, N-phenylglycine, N-phenyldiethanolamine, 3,3 ', 4,4'
-Benzophenone tetracarboxylic acid, tetra-t-butyl peroxide, 5-phenyloxazoline, various oxime compounds, and 1-phenyl-5-mercapto- (1H-tetrazole), 2-mercaptobenzothiazole for improving storage stability. , 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, pentaerythritol tetrakis- (thioglycolate), thioglycolic acid, ammonium thioglycolate, butyl thioglycolate, octyl thioglycolate, methoxybutyl thioglycolate, trimethylolpropane Tris- (thioglycolate), ethylene glycol dithioglycolate, β-mercaptopropionic acid, octyl β-mercaptopropionate, trimethylolpropane tris- (β-thiol Propionate), pentaerythritol tetrakis - (beta-thiopropionate),
1,4-butanediol dithiopropionate, thiosalicylic acid, furfuryl mercaptan, benzyl mercaptan, α-mercaptopropionic acid, p-hydroxythiophenol, p-methylthiophenol, thiophenol and the like may be added.

In addition to the above, an adhesion aid, an inhibitor, a leveling agent and various other fillers may be added to the photosensitive resin composition according to the present invention.

In the method of using the photosensitive resin composition according to the present invention, first, the composition is applied to a suitable support, for example, a silicon wafer, a ceramic, an aluminum substrate or the like. The coating method is spin coating using a spinner, spray coating using a spray coater, dipping, printing, roll coating, or the like. Next, after prebaking at a low temperature of 60 to 80 ° C. to dry the coating film, a desired pattern shape is irradiated with actinic rays. As the actinic rays, X rays, electron rays, 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 unirradiated portion with a developing solution. As a developing solution, N
-Methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, etc., methanol, xylene, isopropyl alcohol, water, alkaline aqueous solution, etc. may be used alone or in combination. As a developing method, methods such as spraying, paddle, dipping, and ultrasonic wave can be used.

Next, the relief pattern formed by development is rinsed. As the rinse liquid, methanol, xylene, ethanol, isopropyl alcohol, butyl acetate, water or the like is used. Next, heat treatment is performed to form an imide ring, and a final pattern having high heat resistance is obtained.

The photosensitive resin composition according to the present invention is useful not only for semiconductor applications, but also as an interlayer insulating film of a multilayer circuit, a cover coat of a flexible copper clad board, a solder resist film, a liquid crystal alignment film and the like.

[0026]

The present invention will be described in detail with reference to the following examples. Example 1 65.5 g (0.30 mol) of pyromellitic dianhydride and 225.5 g (0.70 mol) of 3,3 ′, 4,4′-benzophenone tetracarboxylic acid dianhydride were treated with 2-hydroxy. -1,3-Dimethacryloxypropane 228.0 g
(1.00 mol) with 32.0 g (1.00 mol) of methanol and then esterified with 36,95 g (0.2%) of 2,2-bis [4- (4-aminophenoxy) -phenyl] propane.
9 mol) was used as a condensing agent for dicyclohexylcarbodiimide to obtain a polyamic acid ester copolymer. After dicyclohexylurea was filtered off, it was reprecipitated with ethanol, and the solid substance was filtered and dried under reduced pressure. Next, 100 parts by weight of this polyamic acid ester was added to Michler's ketone (λmax 365).
nm) 5 parts by weight, tetraethylene glycol dimethacrylate 10 parts by weight, trimethoxysilylpropyl methacrylate 3 parts by weight, and methyl ether hydroquinone 0.1 parts by weight are dissolved in 300 parts by weight of N-methylpyrrolidone and 30 parts by weight of xylene, and exposed. A resin composition was obtained. This was applied to a silicon wafer with a nitride film (SiN) using a spinner so that the cured film thickness would be 5 μm. Furthermore, in a curing oven, 150 ° C / 30 minutes in nitrogen, 350 ° C
It was cured for 60 minutes to obtain a polyimide film. The adhesion of this film to a silicon wafer with SiN is determined by JIS-D-0
When measured according to 202, it was 0/10 even after treatment with a pressure cooker at 125 ° C./2.3 atmospheric pressure for 48 hours.
High adhesion was indicated by 0 (number of peeling / total number). Next, E on a wafer with a polyimide film, which was separately prepared by the same method,
ME-6300 (manufactured by Sumitomo Bakelite Co., Ltd.) epoxy-based encapsulating material was molded at 175 ° C. for 3 minutes using a mold, and 2 ×
A molded product of 2 × 2 mm was obtained. Then, post baking was performed at 175 ° C. for 8 hours. This test piece was treated with a pressure cooker for 48 hours, and the shear adhesion was measured using a Tensilon universal tester. Adhesion force of 2.8 kg / mm ²
And showed a high value. The evaluation results are shown in Table 1.

Examples 2 to 10 According to the formulations shown in Table 1, the same reaction as in Example 1 was carried out, the polyamic acid ester was carried out in the same manner as in Example 1, and the same evaluation as in Example 1 was carried out. The evaluation results are shown in Table 1.

Comparative Example 1 Instead of 2,2-bis [4- (4-aminophenoxy) phenyl] propane in Example 1, 180.2 g (0.9 mol) of 4,4'-diaminodiphenyl ether was reacted. The polyamic acid ester was obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As a result, the adhesion was a low value of 0.7 kg / mm ² . Table 1 shows the evaluation results
Shown in. Comparative Example 2 Instead of 2,2-bis [4- (4-aminophenoxy) phenyl] propane in Example 1, 2,2-bis [4-
(4-Aminophenoxy) phenyl] propane 55.4
g (0.135 mol) and 4,4'-diaminodiphenyl ether 153.2 g (0.765 mol) were reacted to obtain a polyamic acid ester by the same operation as in Example 1, and the same evaluation as in Example 1 was performed. The result was 1.4 kg /
The value was as low as mm ² . The evaluation results are shown in Table 1.

[0029]

[Table 1]

[0030]

In the conventional photosensitive resin composition, many inventions have been found for improving the sensitivity and improving the adhesiveness between the substrate such as Si and the polyimide. However, a method for improving the adhesion to the epoxy-based encapsulating material has not been well known. Although it has been reported that the addition of a silane coupling agent improves the adhesion to the epoxy-based encapsulating material, it has a drawback such as a decrease in mechanical strength of the film. The present invention maintains excellent photosensitivity by introducing 2,2-bis [4- (4-aminophenoxy) phenyl) propane into a polyimide structure, while the cured film has a substrate such as Si and an epoxy system. It is possible to obtain a photosensitive polyimide resin which has excellent adhesion to a sealing material and is not deteriorated even after a moisture absorption treatment.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area H01L 21/027

Claims (1)

[Claims] 1. A photosensitive resin composition containing a polyamic acid ester represented by the formula (1) as a main component. [Chemical 1] [Chemical 2]