JP3346981B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a coating for relieving the impact of resin molding during sealing with a plastic mold and the stress generated during various thermal histories 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, a photosensitive polyimide resin includes the following formula (VII).

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When 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 increases, 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]

SUMMARY OF THE INVENTION The present invention is one general formula (II)
100 parts by weight of a polyamide (A), 1 to 100 parts by weight of a photosensitive diazoquinone compound (B), and 1 to 50 parts of a phenol compound (C) represented by the following general formula (III).
After applying a positive photosensitive resin composition consisting of parts by weight on a semiconductor element, prebaking, exposing, developing, patterning and heating and curing , the thickness is 0.1 to 20.
μm of polybenzoxa represented by the following general formula (I)
A semiconductor device wherein a sol resin is formed on a semiconductor element .

[0006]

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[0007]

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[0008]

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The polyamide of the formula (II) comprises bisaminophenol having the structure of X and dicarboxylic acid having the structure of Y. When the polyamide is heated at about 300 to 400 ° C., the ring is closed, and the heat resistance of polybenzoxazole is obtained. Changes to resin. X of the polyamide of formula (II) of the present invention
Is, for example,

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

Among them, those having particularly high sensitivity include:

Embedded image It is more chosen.

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

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

Among these, particularly preferred 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 adhesion is particularly required to a substrate such as a silicon wafer.
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, a polybenzoxazole resin represented by the general formula (I) is formed on a 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, photosensitive pattern processing becomes difficult, which is not preferable in practical use.

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 them, the followings are particularly preferable from the viewpoint of a high residual film ratio.

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The compounding amount of the photosensitive diazidoquinone compound (B) to the polyamide (A) is 1 to 100 parts by weight with respect to 100 parts by weight of the polyamide. If the compounding amount is less than 1 part by weight, the patterning property of the resin is poor. Conversely, if it exceeds 100 parts by weight, the tensile elongation of the film is significantly reduced.
A semiconductor device in which a film having a low tensile elongation is applied to the element surface is not preferable because reliability such as thermal stress deteriorates.

[0020] The positive photosensitive resin composition used in the present invention can be added Jihido Ropi <br/> lysine derivative in order to enhance the photosensitive properties if necessary. Jihido The Ropi lysine 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 can be mentioned.

It is important that the positive photosensitive resin composition of the present invention further contains a phenol compound represented by the general formula (III).

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Techniques for adding a phenol compound to a positive resist composition include, for example, those disclosed in JP-A-3-2002.
No. 51, JP-A-3-200252, JP-A-3-20052
JP-A-200253, JP-A-3-200254, JP-A-4-1650, JP-A-4-1651, JP-A-4-11260, 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 increases, and the sensitivity improves. 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 compound represented by the general formula (III)
As a new property by adding the phenolic compound represented by the formula, a positive photosensitive resin composition having improved adhesion to the sealing resin is obtained, and the reliability of a semiconductor device in which this is applied to the element surface is improved. It turned out to be.

The compounds represented by the general formula (III) include, but are not limited to, the following.

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[0024]

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[0025]

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[0026]

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Among them, particularly preferable in terms of sensitivity and residual film ratio are:

Embedded image The compound represented by the general formula (V) or (VI) is contained alone or in the form of a mixture in an amount of 50% by weight or more in the total phenol compound (C). 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 amount is less than 1 part by weight, the effect of improving sensitivity cannot be obtained, and if the 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 photosensitive resin composition used in the present invention, the composition is first 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, or 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)
36.6 parts (0.100 mol) of hexafluoropropane were dissolved in 150 parts by weight of N, N-dimethylacetamide and 33.2 (0.420 mol) of pyridine. 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 were used.
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 the reaction mixture is filtered, the solution is poured into water and represented by the desired general formula (I):
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 sufficiently with water, and then dried at 80 ° C. under vacuum overnight.

* Preparation of Positive Photosensitive Resin Composition 100 parts by weight of synthesized polyamide (A ₁ ), 25 parts by weight of diazoquinone (Q1) having a structure of the following formula, and a phenol compound (P-1) having a structure of the following formula ) 15 parts by weight were 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 After coating this positive photosensitive resin composition on a silicon wafer using a spin 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 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 immersion 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 this order to cure the resin. 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). The sealing epoxy resin composition formed on the cured polybenzoxazole resin film was peeled off using Tensilon, and the shear strength was measured. As a result, it was 3.8 kg / mm ² .

The above-mentioned positive photosensitive resin composition was applied to a final thickness of 5 μm using a simulated element wafer having an Al circuit on the surface, followed by pattern processing 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 perform high-temperature, high-humidity pressure cooker treatment (125 ° C., 2.3 atm,
(100% RH) to check for open defects in the Al circuit. Table 1 shows the results.

Example 2 The phenolic compound in Example 1 was evaluated in place of the following formula P-2. << Example 3 >> The evaluation was performed by replacing the phenol compound in Example 1 with the following formula P-3. << Example 4 >> The phenolic compound (P-
Evaluation was performed by adding 5 parts by weight of 1). << Example 5 >> In the synthesis of polyamide in Example 1, diphenyl ether-4,4'-dicarboxylic acid chloride was used instead of terephthalic acid chloride and isophthalic acid chloride, and was represented by the following 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 the 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, instead of 3,3'-diamino-4,4'-dihydroxydiphenylsulfone, is represented by the 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 instead of terephthalic acid chloride and isophthalic acid chloride, and represented by the general formula (II). And
X is the following formula X-3, Y is the following formula Y-3, a = 100,
A polyamide (A ₄ ) consisting of b = 0 was synthesized, and a diazoquinone (Q2) having the following structure was used as the diazoquinone to obtain a photosensitive resin composition. Other evaluations were performed 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%).
95 mol), and 1.24 parts by weight (0.005 mol) of 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane was added instead. 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 The reliability of the semiconductor device of Example 1 was evaluated without applying a 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 changed to P-
The evaluation was performed in place of 4. << Comparative Example 9 >> The phenol compound in Example 1 was changed to P-
The evaluation was performed in place of 5. << Comparative Example 10 >> The phenol compound in Example 1 was changed to 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]

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[0040]

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[0041]

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[0042]

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[0043]

[Table 1]

[0044]

According to the present invention, a pattern of a high sensitivity and a high residual film ratio can be obtained, and a positive photosensitive resin composition having excellent adhesion to a sealing resin can be obtained.

Continuation of the front page (56) References JP-A-8-123434 (JP, A) JP-A-7-159990 (JP, A) JP-A-60-150047 (JP, A) JP-A-9-302221 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 73/22 G03F ⁷ /004-7/115 H01L 21/312

Claims (6)

(57) [Claims] 1. A polyamide represented by the general formula (II)
(A) 100 parts by weight and a photosensitive diazoquinone compound (B)
1 to 100 parts by weight of pheno represented by the general formula (III)
-Type photosensitivity comprising 1 to 50 parts by weight of a polyester compound (C)
After applying the resin composition on the semiconductor element, pre-bake,
Exposure, development, patterning and heat curing
A semiconductor device, wherein the obtained 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 Embedded image Embedded image 2. The phenol compound (C) is represented by the general formula (I)
The semiconductor device of claim 1 wherein the phenolic compound represented by V). Embedded image Wherein the phenolic compound is a compound represented by the general formula (V) or (VI), either alone or in the form of a mixture, according to claim 1 or 2, wherein comprising phenol compound (C) total 50 wt% or more Semiconductor device. Embedded image 4. X in the polyamide of the general formula (II)
4. The semiconductor device according to claim 1, wherein the semiconductor device is selected from the following. Embedded image 5. Y in the polyamide of the general formula (II)
5. The semiconductor device according to claim 1, wherein the component is selected from the following. Embedded image 6. The photosensitive diazoquinone compound (B) is a semiconductor device according to claim 1, 2, 3, 4 or 5, wherein comprising been selected from the following. Embedded image