JPH09321038A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the adhesion of a photosensitive resin to a seal resin to avoid peeling one resin from the other at their interface by forming a polybenzooxazol resin shown by specified formula in specified thickness range on a semiconductor device. SOLUTION: A polybenzooxazol resin of 0.1-20μm thick, shown by formula 1 is formed on a semiconductor element wherein X is tetravalent aromatic group, Y bivalent aromatic group, a, b are mol percent, a+b=100mol%, a=60.0-100.0mol%, b=0-40.0mol% and n=2-500. Using a positive type photosensitive resin superior in adhesion to a seal resin, a pattern of the polybenzooxazol resin having a high film residual ratio is formed to improve the adhesion of the photosensitive resin to the seal resin and avoid peeling at their interface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device provided with a coating film that relieves the stress caused by the impact of resin molding operation during sealing with a plastic mold and various thermal history after molding. .

[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, thinning and miniaturization of the encapsulation resin package, transition to surface mounting by solder reflow, etc., and further high performance polyimide resin Is becoming necessary. On the other hand, the technology of imparting photosensitivity to the polyimide resin itself has recently attracted attention,
For example, as the photosensitive polyimide resin, there is the following formula (VII).

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If this is used, a part of the pattern forming process can be simplified and the process can be shortened.
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 composed of a polybenzoxazole resin and a diazoquinone compound. It has high heat resistance, excellent electrical properties and fine workability, and has the potential not only as a wafer coat but also as an interlayer insulating resin. The mechanism of development of this positive photosensitive resin is such that the diazoquinone compound in the unexposed area is insoluble in the alkaline aqueous solution, but the exposure causes the diazoquinone compound to undergo a chemical change and become soluble in the 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. When these photosensitive resins are actually used, a particular problem is the sensitivity of the photosensitive resin. With low sensitivity,
The exposure time per wafer becomes long and the throughput decreases. In order to improve the sensitivity of the photosensitive resin, for example, if the molecular weight of the polyamide resin as the base resin is reduced, there is a problem that the film loss of the unexposed portion during development is increased, and the pattern shape is deteriorated. In addition, adhesion between the photosensitive resin and the sealing resin is poor, and peeling occurs at the interface, and the reliability of the semiconductor device coated with this on the element surface is reduced, and there is a problem in practicality. It has been strongly demanded to use a photosensitive resin having excellent adhesiveness with the resin.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for forming a high-residual polybenzoxazole resin pattern on a semiconductor device using a positive photosensitive resin having excellent adhesion to a sealing resin. It is an object to provide a reliable semiconductor device.

[0005]

The present invention is characterized in that a polybenzoxazole resin represented by the following general formula (I) having a thickness of 0.1 to 20 μm is formed on a semiconductor element. The polybenzoxazole resin represented by the general formula (I) is a device represented by the following general formula (II)
A positive photosensitive resin comprising 100 parts by weight of the polyamide (A) represented by the formula (1), 1 to 100 parts by weight of the photosensitive diazoquinone compound (B), and 1 to 50 parts by weight of the phenol compound (C) represented by the following general formula (III). A semiconductor device obtained by applying a resin composition onto a semiconductor element, pre-baking, exposing, developing and patterning and then heating and curing.

[0006]

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[0007]

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[0008]

[Chemical 12]

The polyamide of the formula (II) comprises a bisaminophenol having a structure of X and a dicarboxylic acid having a structure of Y, and when the polyamide is heated at about 300 to 400 ° C., the ring is closed to give a heat-resistant polybenzoxazole. Change to resin. X of the polyamide of formula (II) according to the invention
Is, for example,

Embedded image Etc., but are not limited to these.

Among these, particularly high sensitivity is as follows.

Embedded image It is more chosen.

Y in the formula (II) is, for example,

Embedded image Etc., but are not limited to these.

Among these, particularly preferable are

Embedded image It is more chosen.

Further, Z in the formula (II) is, for example,

Embedded image Etc., but are not limited to these.

Z in the formula (II) is used, for example, when it is necessary to adhere to a substrate such as a silicon wafer, and the use ratio b is 40.0 mol% at maximum.
Can be used up to. If it exceeds 40.0 mol%, the solubility of the resin is extremely reduced, scum is generated, and pattern processing cannot be performed. When using X, Y, and Z, one type or a mixture of two or more types may be used.

In the semiconductor device of the present invention, the polybenzoxazole resin represented by the general formula (I) is formed on the semiconductor element in a thickness of 0.1 to 20 μm. If the thickness is less than 0.1 μm, the effect of relieving thermal stress is poor, and
If it exceeds μm, it becomes difficult to process the photosensitive pattern, which is not preferable in practice.

The photosensitive diazoquinone compound used in the present invention is a compound having a 1,2-benzoquinonediazide or 1,2-naphthoquinonediazide structure, and is disclosed in US Pat. Nos. 2,772,972 and 2,797, 21
No. 3,669,658. For example, the following are mentioned.

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[0017]

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Among these, the following are particularly preferable from the viewpoint of high residual film ratio.

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The photosensitive diazidoquinone compound (B) is compounded in the polyamide (A) in an amount of 1 to 100 parts by weight, based on 100 parts by weight of the polyamide. If the amount is less than 1 part by weight, the patterning property of the resin is poor. On the other hand, if the amount exceeds 100 parts by weight, the tensile elongation of the film is significantly reduced.
A semiconductor device in which a film having a small tensile elongation is applied to the surface of the element is not preferable because reliability is lowered by stress such as thermal stress.

If desired, a dihydroxypyridine derivative may be added to the positive-type photosensitive resin composition used in the present invention in order to enhance the photosensitivity. 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-
Examples thereof include 1,4-dihydropyridine and 4- (2 ', 4'-dinitrophenyl) -2,6-dimethyl-3,5-carbomethoxy-1,4-dihydropyridine.

In the positive photosensitive resin composition of the present invention, it is important to further contain a phenol compound represented by the general formula (III).

[Chemical 21]

A technique for adding a phenol compound to a positive resist composition is, for example, Japanese Patent Laid-Open No. 3-2002.
No. 51, JP-A-3-200252, JP-A-3-20052
-200253, JP-A-3-200254, JP-A-4-1650, JP-A-4-1651, JP-A-4-11260, and JP-A-4-123.
No. 56, JP-A-4-12357. However, phenol compounds such as those described above have a small effect of improving sensitivity even when used in a positive photosensitive resin containing a polyamide as a base resin in the present invention.
However, when the phenol compound represented by the general formula (III) in the present invention is used, the dissolution rate in the exposed area is increased and the sensitivity is improved. In addition, the film loss in the unexposed portion, which is observed when the sensitivity is increased by reducing the molecular weight, is very small and good. In the present invention, the general formula (III)
As a new property by adding the phenolic compound represented by, a positive photosensitive resin composition with improved adhesion to the sealing resin is obtained, and the reliability of the semiconductor device coated with this on the element surface is improved. It turned out to be.

Examples of the compound represented by the general formula (III) include, but are not limited to, the followings.

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[0024]

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[0025]

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[0026]

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Of these, particularly preferable in terms of sensitivity and residual film ratio are:

[Chemical formula 26] The compound represented by the general formula (V) or (VI) is contained alone or in the form of a mixture in the total phenol compound (C) in an amount of 50% by weight or more. The amount of the phenol compound (C) to be added is preferably 1 to 50 parts by weight based on 100 parts by weight of the polyamide (A). If the addition amount is less than 1 part by weight, the effect of improving the sensitivity cannot be obtained, and the addition amount is 50
If the amount is more than 10 parts by weight, the residual film ratio is greatly reduced, or precipitation occurs during frozen storage, which is not practical.

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 type photosensitive resin composition used in the present invention, first, the composition is applied to a semiconductor wafer. As the coating method, the film thickness can be easily controlled by variously changing the application conditions such as the spinner rotation number for performing spin coating using a spinner, spray coating using a spray coater, immersion, printing, roll coating, and the like. Thickness after final baking is 0.1-2
The thickness is set to 0 μm. Next, after pre-baking at 60 to 120 ° C. to dry the coating film, a desired pattern shape is irradiated with actinic radiation. X-rays, electron beams, ultraviolet rays,
Visible light or the like can be used, but those having a wavelength of 200 to 500 nm are preferred. Next, a relief pattern is obtained by dissolving and removing the irradiated portion with a developer. As a developer,
Sodium hydroxide, potassium hydroxide, sodium carbonate,
Inorganic alkalis such as sodium silicate, sodium metasilicate and aqueous ammonia, primary amines such as ethylamine and n-propylamine, secondary amines such as diethylamine and di-n-propylamine, triethylamine and methyldiethylamine Aqueous solutions of alkali amines such as tertiary amines, alcoholamines such as dimethylethanolamine and triethanolamine, and quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide, and methanol and ethanol; An aqueous solution to which a suitable amount of a water-soluble organic solvent such as alcohols or a surfactant is added 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.

[0030]

The present invention will be described below in detail with reference to examples. << Example 1 >> * Synthesis of polyamide 2,2-bis (3-amino-4-hydroxyphenyl)
Hexafluoropropane (36.6 parts by weight, 0.100 mol) was dissolved in N, N-dimethylacetamide (150 parts by weight) and pyridine (33.2, 0.420 mol). Next, 17.0 parts by weight (0.084 mol) of terephthalic acid chloride and 4.3 parts by weight (0.021 mol) of isophthalic acid chloride dissolved in 100 parts by weight of cyclohexanone.
Was added dropwise at -10 to -15 ° C over 30 minutes, followed by stirring at room temperature for 4 hours to complete the reaction. After filtering the reaction mixture, the solution is poured into water and represented by the general formula (I) of interest,
X is a mixture of the following formulas X-1 and Y is a mixture of the following formulas Y-1 and Y-2 to precipitate a polyamide (A ₁ ) consisting of a = 100 and b = 0. The precipitate was collected by filtration, washed thoroughly with water, and dried under vacuum at 80 ° C. for 24 hours.

* Preparation of Positive Photosensitive Resin Composition 100 parts by weight of synthesized polyamide (A ₁ ), 25 parts by weight of diazoquinone (Q1) having the structure of the following formula, and phenol compound (P-1) having the structure of the following formula ) 15 parts by weight was dissolved in 200 parts by weight of N-methyl-2-pyrrolidone and then filtered through a 0.2 μm Teflon filter to obtain a photosensitive resin composition.

* Characteristic Evaluation This positive photosensitive resin composition was applied onto a silicon wafer using a spin coater and then dried in an oven at 70 ° C. for 1 hour to obtain a coating film having a thickness of about 5 μm. A g-line stepper exposure machine NSR-1505G3A (Nikon
The exposure from 50 mJ / cm ² through a reticle to 20 mJ / cm ² increments increased by 540mJ / cm ² was performed by Co.). Next, the exposed portion was dissolved and removed by immersing it in a 0.79% tetramethylammonium hydroxide aqueous solution for 30 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 200 mJ / cm ² . (The sensitivity is 200 mJ / cm ² ). At this time, the residual film ratio (film thickness after development / film thickness before development) was as high as 91.3%. Separately, a positive photosensitive resin composition is similarly coated on a silicon wafer, prebaked, and then placed in an oven.
0 minutes / 150 ° C, 30 minutes / 250 ° C, 30 minutes / 350 ° C
In that order, the resin was cured by heating. Furthermore, an epoxy resin composition for semiconductor encapsulation (Sumitomo Bakelite Co., Ltd.)
Manufactured by EME-6300H) 2 x 2 x 2 mm (horizontal x vertical x
(Height). Using Tensilon, the epoxy resin composition for encapsulation molded on the polybenzoxazole resin cured film was peeled off, and the shear strength was measured and found to be 3.8 kg / mm ² .

The positive type photosensitive resin composition was applied to a final thickness of 5 μm using a simulated element wafer having an Al circuit on the surface thereof, followed by patterning and final baking. After that, it is divided for each chip size and 16 Pin DIP (Du
al Inline Package) was mounted using a conductive paste, and then molded with an epoxy resin for semiconductor encapsulation (manufactured by Sumitomo Bakelite Co., Ltd., EME-6300H) to obtain a 16-pin DIP. After treating these packages at 85 ° C./85% humidity for 168 hours,
Immerse in a 60 ° C solder bath for 10 seconds, and then heat cooker at high temperature and high humidity (125 ° C, 2.3 atm,
(100% RH) to check for open defects in the Al circuit. Table 1 shows the results.

Example 2 The phenol compound in Example 1 was replaced by the following formula P-2 for evaluation. << Example 3 >> The phenol compound in Example 1 was replaced with the following formula P-3 for evaluation. << Example 4 >> The phenolic compound (P-
Evaluation was carried out by adding 5 parts by weight of 1). << Example 5 >> In the synthesis of the polyamide in Example 1, diphenyl ether-4,4'-dicarboxylic acid chloride was used instead of terephthalic acid chloride and isophthalic acid chloride, and the compound was represented by the general formula (II) and X was represented by the following formula. X-
1, a polyamide (A ₂ ) having Y = the following formula Y = a = 100 and b = 0 was synthesized, and the other evaluations were performed in the same manner as in Example 1.

Example 6 In the synthesis of polyamide in Example 1, diphenyl ether-4,4'- was used instead of terephthalic acid chloride and isophthalic acid chloride.
Dicarboxylic acid chloride is used and 2,2-bis (3
-Amino-4-hydroxyphenyl) hexafluoropropane was replaced with 3,3'-diamino-4,4'-dihydroxydiphenyl sulfone to give a compound of general formula (II)
X is the following formula X-2, Y is the following formula Y-3,
= 100, and the synthesis of b = 0 a polyamide (A _3), others were evaluated in the same manner as in Example 1. << Example 7 >> In the synthesis of the polyamide in Example 1, 3,3′-diamino-4,4′-dihydroxydiphenyl ether was used in place of terephthalic acid chloride and isophthalic acid chloride, and was represented by the general formula (II). Is
X is the following formula X-3, Y is the following formula Y-3, and a = 100,
A polyamide (A ₄ ) having b = 0 was synthesized, and a diazoquinone (Q2) having the following structure was used as the diazoquinone to obtain a photosensitive resin composition. Others were evaluated in the same manner as in Example 1. . Example 8 In the synthesis of the polyamide in Example 1, 2,1.9% by weight of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane was added to 31.9 parts by weight (0.0%).
To 95 mol), and instead, 1.24 parts by weight (0.005 mol) of 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane was added to give the compound of the general formula (II ), X is the following formula X-1, and Y is the following formula Y-1.
And Y-2, Z is the following formula Z-1, a = 95, b
= A five polyamide (A ₅₎ were synthesized, others were evaluated in the same manner as in Example 1.

Comparative Example 1 In the reliability evaluation of the semiconductor device of Example 1, the evaluation was performed without applying the polybenzoxazole resin to the element surface. << Comparative Example 2 >> In the resin characteristic evaluation of Example 1, the film thickness 3
As a result of performing pattern processing at 0 μm, 1000 mJ /
Even after exposure to cm ² , the resin was dissolved in the exposed area after development, and patterning could not be performed. << Comparative Example 3 >> Evaluation was made in Example 1 without adding a phenol compound. << Comparative Example 4 >> Evaluation was made in Example 5 without adding a phenol compound. << Comparative Example 5 >> Evaluation was made in Example 6 without adding a phenol compound. << Comparative Example 6 >> The evaluation was performed by reducing the amount of the phenol compound added in Example 1 to 0.5 part by weight. << Comparative Example 7 >> The evaluation was performed by increasing the amount of the phenol compound added in Example 1 to 60 parts by weight. << Comparative Example 8 >> The phenol compound in Example 1 was mixed with P-
The evaluation was performed in place of 4. << Comparative Example 9 >> P- was used as the phenol compound in Example 1.
The evaluation was performed in place of 5. << Comparative Example 10 >> The phenol compound in Example 1 was added as P.
The evaluation was performed in place of -6. The evaluation results of Examples 1 to 8 and Comparative Examples 1 to 8 are shown in Table 1.

[0037]

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[0038]

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[0039]

[Chemical 29]

[0040]

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[0041]

[Chemical 31]

[0042]

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[0043]

[Table 1]

[0044]

EFFECTS OF THE INVENTION According to the present invention, a positive photosensitive resin composition can be obtained in which a highly sensitive pattern having a high residual film ratio can be obtained and which has excellent adhesiveness to a sealing resin.

Front page continued (72) Inventor Naoshi Takeda 2-5-8 Higashi-Shinagawa, Shinagawa-ku, Tokyo Sumitomo Bakelite Co., Ltd.

Claims (7)

[Claims] 1. A semiconductor device in which a polybenzoxazole resin represented by the general formula (I) having a thickness of 0.1 to 20 μm is formed on a semiconductor element. Embedded image 2. A polybenzoxazole resin comprising 100 parts by weight of a polyamide (A) represented by the general formula (II), 1 to 100 parts by weight of a photosensitive diazoquinone compound (B) and a phenol compound represented by the general formula (III). (C) 1 to 50
The semiconductor device according to claim 1, which is obtained by applying a positive type photosensitive resin composition consisting of parts by weight onto a semiconductor element, pre-baking, exposing, developing and patterning and then heating and curing. Embedded image Embedded image 3. The phenol compound (C) has the general formula (I
The semiconductor device according to claim 2, which is a phenol compound represented by V). Embedded image 4. The phenol compound is a compound represented by the general formula (V) or (VI), and 50% by weight or more of the whole phenol compound (C) is contained alone or in the form of a mixture. Semiconductor device. Embedded image 5. X in the polyamide of general formula (II)
5. The semiconductor device according to claim 2, wherein the component is selected from the following. [Chemical 6] 6. Y in the polyamide of the general formula (II)
6. The semiconductor device according to claim 2, wherein the component is selected from the following. [Chemical 7] 7. The semiconductor device according to claim 2, wherein the photosensitive diazoquinone compound (B) is selected from the following. Embedded image