JPH0551541A - Inorganic filler coated with polyimide resin, resin composition containing the same, and semiconductor device encapsulated with the resin composition - Google Patents

Abstract

(57) [Abstract] [Object] In a semiconductor device encapsulated with a resin composition, since the device excellent in heat resistance, moisture resistance, and thermal shock resistance can be obtained, a sealing resin suitable for the device and An inorganic filler coated with a resin having excellent properties, which is a raw material of the resin composition, is obtained. [Structure] General formula (I): After being coated with a terminal silicon-modified polyamic acid compound represented by, an inorganic filler having an imidized coating layer, a resin composition containing the coated filler, and a resin composition encapsulated with the resin composition Semiconductor device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic filler coated with a polyimide resin, which is preferably used for sealing resins, adhesives, varnishes, paints, laminated boards, etc. in semiconductor devices.
The present invention relates to a resin composition containing the same and a semiconductor device sealed with the resin composition.

More specifically, an inorganic filler whose surface has been coated with a polyimide resin having a small coefficient of thermal expansion due to its rigid molecular structure and excellent in high adhesion and high heat resistance, and by blending it with the thermal shock resistance And a semiconductor device encapsulated with the resin composition.

[0003]

2. Description of the Related Art In semiconductor devices such as ICs and LSIs, a resin encapsulation method for encapsulating the semiconductor element with a silicone resin, an epoxy resin or the like is widely adopted.
Among these encapsulating resins, a novolac-based epoxy resin composition (see, for example, JP-A-63-77930)
Is widely used because it can effectively and satisfactorily maintain the moisture resistance after sealing and is relatively inexpensive.

However, when a large-capacity semiconductor element is sealed with this epoxy resin composition, stress due to contraction during curing or stress caused by a difference in coefficient of thermal expansion between the internal element and the epoxy resin causes There are problems that the bonding wire of the element is easily deformed, broken, or cracked in the element passivation.

In order to reduce these stresses, a method of adding a flexibility-imparting agent such as silicone rubber and polystyrene block copolymer into the epoxy matrix to reduce the generated thermal stress (JP-A-63-248820). (See the official gazette) and the like are being considered.

Further, as a method for reducing the difference in coefficient of thermal expansion between the internal element and the sealing resin, generally, in the resin composition,
Inorganic fillers with an addition amount of 70% (wt%, the same applies below) or more are added. In this case, in order to improve the adhesion between the inorganic filler and the resin matrix, the surface of the inorganic filler is coated with a silane coupling agent.

However, the resin composition containing the inorganic filler subjected to the coating treatment is exposed to a high temperature in a heat treatment process such as soldering, and stress is applied to the interface between the inorganic filler and the matrix resin during the subsequent cooling process to room temperature. Is induced, which leads to a decrease in adhesion and causes cracks at the interface between the inorganic filler and the matrix resin.

In order to solve the above problems, the present inventors have proposed a resin composition in which a silicone resin is uniformly dispersed in an epoxy matrix (see Japanese Patent Application Laid-Open No. 61-66712), and have further improved stability. It has been proposed a resin composition (see Japanese Patent Application Laid-Open No. 63-58860) that realizes a reduction in stress and a reduction in stress.

[0009]

The resin composition provides a resin composition for semiconductor encapsulation which is excellent in crack resistance and moisture resistance and is stable. Since the difference in the coefficient of thermal expansion between the resin matrix such as epoxy and the inorganic filler still remains, a large stress is generated at the interface. However, since the heat resistance of the silane coupling agent used as an adhesion improving component is low, the adhesion at the interface after high temperature treatment is low, and because the film thickness is very thin, the heat of the resin matrix and inorganic filler is It was found that the stress generated at the interface could not be sufficiently reduced due to the difference in expansion coefficient, the mechanical strength of the resin composition was lowered, and a package crack was generated in the assembly process of the resin sealing element.

As described above, the resin composition for semiconductor encapsulation in which the silicone resin is dispersed has excellent crack resistance,
Although it is a resin composition that exhibits moisture resistance, stability, and low stress, it further improves the adhesiveness of the interface between the resin matrix and the inorganic filler at high temperatures, and the coefficient of thermal expansion at these interfaces. It is necessary to form a layer that relieves the stress caused by the difference between

The present invention has been made in order to solve the above problems, and improves the adhesion between the resin matrix and the inorganic filler, and not only has high heat resistance, but also has the thermal stress generated by cold shock. An object is to obtain an inorganic filler coated with a resin that can be sufficiently relaxed, a resin composition containing the same, and a semiconductor device encapsulated with the resin composition.

[0012]

That is, the present invention provides a compound represented by the general formula (I):

[0013]

[Chemical 2] (In the formula, R ¹ is an organic group having 1 to 5 carbon atoms, and R ² and R ³ are 2
An organic filler having a valent organic group, R ⁴ is a tetravalent organic group, and n is an integer of 2 or more), and an inorganic filler having a coating layer that is imidized after being coated with a terminal silicon-modified polyamic acid compound The present invention relates to an inorganic filler coated with a polyimide resin, a resin composition containing the inorganic filler coated with the polyimide resin, and a semiconductor device sealed with the resin composition.

[0014]

FUNCTIONS AND EXAMPLES The terminal silicon-modified polyamic acid compound represented by the general formula (I) (hereinafter referred to as polyamic acid compound) used in the present invention has excellent adhesiveness with the inorganic filler and the resin composition, By imidizing, a tough film having high heat resistance and low thermal expansion can be obtained.

R ¹ in the general formula (I) is an organic group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group,
Examples include propyl group. R ² is a divalent organic group, and specifically,

[0016]

[Chemical 3] And so on. R ³ is a divalent organic group, and specifically,

[0017]

[Chemical 4] Etc. R ⁴ is a tetravalent organic group, and specifically,

[0018]

[Chemical 5] And so on. n is 2 or more, and the molecular weight thereof is preferably a value corresponding to 6,000 to 10,000.

Examples of the polyamic acid compound include, for example,

[0020]

[Chemical 6] Can be given.

The polyamic acid compound may be obtained by any method, for example, a known method from tetracarboxylic dianhydride, diamine and alkoxyaminosilane (J. Polymeric Mater.). 1982, Vol. 9, p225)).

Specific examples of the tetracarboxylic dianhydride include, for example, pyromellitic dianhydride, 3,3 ', 4,4'-
Biphenyltetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride, 2,3,3 '4,4'-benzophenone tetracarboxylic acid dianhydride and the like.

Specific examples of the diamine include, for example, 4,
4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 4,
4'-di (meta-aminophenoxy) diphenyl sulfone, 4,4'-di (para-aminophenoxy) diphenyl sulfone, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,2'-diaminobenzophenone Aromatic diamine such as 4,4'-diaminobenzophenone and 4,4'-diaminodiphenyl-2,2'-propane, trimethylenediamine, hexamethylenediamine, tetramethylenediamine, 4,4'-dimethylheptamethylenediamine Such as aliphatic diamine.

Specific examples of the alkoxyaminosilane compound include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminobutyltriethoxysilane, 3-aminobutyltrimethoxysilane and aminophenyltriethoxysilane. Examples thereof include silane and aminophenyltrimethoxysilane.

The inorganic filler coated with the polyamic acid compound preferably has a particle size of 150 μm.
Various shapes such as spherical, crushed, flake-shaped, and needle-shaped can be used as long as m or less. Specific examples of the inorganic filler include
Examples thereof include fused silica, crystalline silica, crystalline alumina, alumina, silicon carbide and calcium carbonate.

Next, the formation of the coating layer of the inorganic filler with the polyamic acid compound can be carried out, for example, by adding the polyamic acid compound and the inorganic filler to an organic solvent and stirring the mixture.

In this case, for example, a polyamic acid compound
Containing 0.1 to 10 parts (parts by weight, the same below), for example N-
90 to 99.9 parts of organic solvent such as methylpyrrolidone, γ-butyrolactone, dimethylformamide, etc.
Add 100 parts, stir at a temperature of 40 ° C. or lower for about 2 hours, and dry by a method such as spray drying,
An inorganic filler having a coating layer of a polyamic acid compound is obtained.

If the amount of the polyamic acid coated per 100 parts of the inorganic filler is less than 0.1 part, the coating layer becomes too thin, and after the imidization treatment, when incorporated into the resin composition, the stress relaxation effect is weakened. On the other hand, if it exceeds 10 parts, the filler tends to aggregate easily when the filler is mixed in the solution of the polyamic acid compound.

The coating layer is formed by using a powder mixer such as a Henschel mixer and dissolving the polyamic acid compound or the polyamic acid compound in an organic solvent such as N-methylpyrrolidone on the surface while mixing the inorganic filler. You may perform it by the method of atomizing the liquid.

Next, the imidization treatment of the polyamic acid compound coated on the surface of the inorganic filler is performed. Here, the imidization treatment is a process in which the polyamic acid compound is dehydrated and cyclized to form a polyimide. In the present invention, the imidization treatment, 100 parts of the inorganic filler, for example, acetic anhydride 80 ~ 1
It can be carried out by adding 20 parts, 220 to 260 parts of pyridine and 340 to 380 parts of benzene and stirring at a temperature near room temperature for 12 hours or more. Thereafter, in order to remove the attached solvent and the like, drying such as vacuum drying is performed at 150 to 200 ° C. for 2 to 3 hours.

The imidization reaction may be carried out by heating and curing at 300 to 350 ° C. in a stream of an inert gas such as nitrogen or argon, but the particle size of the inorganic filler is as small as 50 μm or less. If it becomes too small, particles in contact with each other during heat curing tend to aggregate, so the chemical cyclization treatment is desirable.

By the above method, an inorganic filler coated with a polyimide resin is obtained. In this case, the ratio of the coating layer to the inorganic filler is preferably 0.2-5%, more preferably 0.5-2%.

The inorganic filler coated with the polyimide resin of the present invention (hereinafter referred to as coating treatment filler) has a high heat resistance of the polyimide resin itself of 300 to 400 ° C., and the adhesion between the polyimide resin and the surface of the inorganic filler is high. It is favorable because the polyimide has a molecular chain and an inorganic substance and a functional group having a high relaxation power. Therefore, the coating treatment filler has high heat resistance by blending with one or more appropriate resins to form a resin composition, and a semiconductor device in which thermal stress generated by cold shock can be sufficiently relaxed. The resin composition is most suitable for sealing.

The coating treatment filler can also be suitably used as an adhesive, a varnish, a paint, a laminate, etc. by combining it with various resins and solvents.

Next, a resin composition suitable for semiconductor encapsulation, in which the coating filler is mixed with a resin that serves as a matrix, a curing agent, etc., will be described.

As the resin, either a thermosetting resin or a thermoplastic resin can be used.

Any thermosetting resin may be used as long as it is generally used. For example, a novolac type epoxy resin or bisphenol generally used as a sealing resin for semiconductors and the like. A-type epoxy resin, tris (hydroxyphenyl) methane-based epoxy resin, naphthalene-based epoxy resin, brominated epoxy resin, and the like, and one or a combination of two or more of these resins are preferable. A combination using an epoxy resin such as the silicone-based epoxy resin proposed in JP 61-66712 is more preferable.

When the thermosetting resin is used, a phenol novolac resin, an acid anhydride, an amine curing agent, etc. are used depending on the resin used and the combination thereof. Of these, phenol novolac resin is preferable in terms of moisture resistance.

Examples of the thermoplastic resin to be added to the coating filler may be any resin as long as it is a thermoplastic resin such as polyimide, PES or PEEK, but the coating filler may be added to the resin. When mixing, a resin having a melt viscosity capable of being mixed at a temperature of 400 ° C. or lower is preferable.

Further, the thermoplastic resin is preferably a resin soluble in an organic solvent. Further, it is more preferable if there is a powdered thermoplastic resin.

Next, as a method for obtaining the resin composition by blending the coating treatment filler with a resin or the like, the coating treatment filler is added to the thermosetting resin or the thermoplastic resin in an amount of 10%.
~ 90% addition, and then a curing agent, flame retardant aid, release agent, colorant, etc., and if necessary, a curing catalyst, etc.,
It can be obtained by mixing using a mixing device which has been conventionally blended and used for adjusting a semiconductor sealing material, such as a roll, a kneader, a liquor machine or a Henschel mixer. The obtained resin composition is, for example, then crushed, and the diameter is 10 to 50 mm and the height is
If it is made into a tablet with a thickness of 10 to 50 mm, it can be suitably used for semiconductor encapsulation.

Especially for applications requiring a low coefficient of thermal expansion, such as semiconductor encapsulation, it is preferable that the content of the polyimide resin coating filler is as high as possible, and the amount is 60 to 90%. preferable. In this case,
The coefficient of thermal expansion is 28 to 6 ppm / ° C.

The resin composition contains an inorganic filler coated with a polyimide resin therein, the polyimide resin layer has high heat resistance, and the adhesiveness to the inorganic filler and the resin to be the matrix is very high. Therefore, as compared with a resin composition containing a conventionally used silane coupling agent, high adhesion between the inorganic filler and the matrix resin can be maintained even after high-temperature treatment.

Further, the resin composition has a coefficient of thermal expansion which is an intermediate value between that of the conventional matrix resin and the inorganic filler and has a film thickness larger than that of the conventional silane coupling agent. The generated stress is reduced, and the generated stress is absorbed and relaxed by the polyimide layer.
The above effects could not be realized with a conventional resin composition containing an inorganic filler subjected to silane coupling treatment. As a result, it is possible to reduce the occurrence of stress at the time of cold thermal shock of the semiconductor encapsulated using the resin composition, and to significantly improve the crack resistance.

In this way, since the resin composition suitable for semiconductor encapsulation can be obtained, a semiconductor element can be encapsulated using the resin composition.

Examples of the semiconductor element sealed with the resin composition of the present invention include ordinary silicon elements such as memory elements and CPU elements.

Next, as a method for sealing the element with the resin composition, a method using a normal transfer molding machine can be mentioned.

The semiconductor element sealed with the obtained resin composition becomes a highly reliable semiconductor device without problems such as deformation of the bonding wire, disconnection, and cracking of element passivation.

Example 1 Formula:

[0050]

[Chemical 7] N-methylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.) containing 1 part of a terminal silicon-modified polyamic acid compound represented by
Inorganic filler (spherical silica, average particle size 13
100 μm) was added, and the mixture was stirred at a temperature of 40 ° C. or lower for 2 hours. Next, this is powder-dried using a spray dryer,
An inorganic filler coated with a polyamic acid compound was obtained. Next, the inorganic filler coated with a polyamic acid compound was added to a mixed solution of 100 parts of acetic anhydride, 240 parts of pyridine and 360 parts of benzene, and the mixture was stirred at room temperature for 12 hours or more. After stirring, 18
It was vacuum dried at 0 ° C. for 2 hours to obtain a coated inorganic filler. Infrared absorption spectrum measurement of the inorganic filler subjected to the coating treatment (manufactured by Shimadzu Corporation, FT-IR4
300), it was found that the coating layer was wholly polyimidized. Further, the amount of the polyimide resin with respect to the spherical silica was analyzed by thermogravimetric analysis (TGA-7 manufactured by Perkin-Elmer Co.), and it was about 2%.

Example 2 Using the inorganic filler coated with the polyimide resin obtained in Example 1, an epoxy resin composition for semiconductor encapsulation was prepared as follows. As an epoxy resin, triglycidyl ether of tris (hydroxyphenyl) methane (EPPN 501 (epoxy equivalent: 160-170) manufactured by Nippon Kayaku Co., Ltd.) 90 parts, brominated epoxy resin (BREN (manufactured by Nippon Kayaku Co., Ltd.) Epoxy equivalent 270-300)) 10 parts,
57 parts of phenol novolac resin (PSM4327 manufactured by Gunei Chemical Industry Co., Ltd.) as a curing agent, 540 parts of an inorganic filler coated with a polyimide resin and 1.2 parts of trifelphosphine as another additive, 1 part of carbon black, carnauba Mix 2 parts wax and 10 parts antimony trioxide,
After kneading with a hot roll at 70-100 ° C for 4-7 minutes,
It was crushed and molded into a tablet having a diameter of 45 mm and a height of 35 mm with a pressing device so as to have a bulk density of 1.5 to 1.8 to obtain an epoxy resin composition for semiconductor encapsulation.

[Example 3] 100 parts of phenol novolac epoxy resin (DEN 438 (epoxy equivalent: 176 to 181) manufactured by Dow Chemical Japan Co., Ltd.) as an epoxy resin, general formula:

[0053]

[Chemical 8] (Wherein, n is about 4.5 and the number average molecular weight is about 660) 6 parts of both-terminal allylphenol-modified silicone, both-terminal p-hydroxystyrene-modified silicone (X manufactured by Shin-Etsu Chemical Co., Ltd.) -22-165B (OH number 27, dimethyl siloxane polymerization degree about 50, number average molecular weight about 400
0)) 12 parts and 0.4 parts triphenylphosphine were used to prepare a silicone modified epoxy resin.

Using the silicone modified epoxy resin thus obtained and the inorganic filler coated with the polyimide resin obtained in Example 1, an epoxy resin composition for semiconductor encapsulation was prepared as follows. Triglycidyl ether of tris (hydroxyphenyl) methane as epoxy resin (EPPN501 manufactured by Nippon Kayaku Co., Ltd. (epoxy equivalent 1
60 to 170)) 10 parts, brominated epoxy resin (BREN (epoxy equivalent 270 to 300) manufactured by Nippon Kayaku Co., Ltd.) 10 parts, phenol novolac resin (PSM4327 manufactured by Gunei Chemical Industry Co., Ltd.) as a curing agent. ) 50 parts, 95 parts of the silicone-modified epoxy resin, inorganic filler coated with polyimide resin 55
0 part, Trifelphosphine 1.2 as other additives
Parts, carbon black 1.15 parts, carnauba wax 2 parts,
10 parts of antimony trioxide was mixed and prepared, kneaded with a hot roll of 70 to 100 ° C. for 4 to 7 minutes, and then pulverized, and a press machine was used to obtain a bulk density of 1.5 to 1.8 and a diameter of 45 mm and a height of 35 mm. Molded into tablets, an epoxy resin composition for semiconductor encapsulation was obtained.

[Comparative Examples 1 and 2] Instead of the inorganic filler coated with the polyimide resin obtained in Example 1, a usual silane coupling agent (KBM-40 manufactured by Shin-Etsu Chemical Co., Ltd.) was used.
Except for using the filler treated in 3), the mixture was prepared in the same manner as in Example 2 or 3 in the proportions shown in Example 2 or 3, kneaded with a hot roll at 70 to 100 ° C for 4 to 7 minutes, and then pulverized. Then, using a pressing device, a tablet having a diameter of 45 mm and a height of 35 mm was formed into a tablet having a bulk density of 1.5 to 1.8 to obtain an epoxy resin composition for semiconductor encapsulation. The content of the silane coupling agent in the filler treated with the silane coupling agent and the thickness of the layer of the silane coupling agent were analyzed in the same manner as in Example 1. The content was below the measurement limit value. It was

[Examples 4 and 5, Comparative Examples 3 and 4] Using the tablets obtained in Examples 2 and 3 and Comparative Examples 1 and 2, the plunger pressure was 80 kg / cm ² , and the mold temperature was 175 ± 5. ℃,
Transfer molding was carried out under the condition that the molding time was 90 seconds, and the following various monitor chips for reliability evaluation and various test pieces for evaluation were produced. Next, the various reliability evaluation monitor chips and various evaluation test pieces were post-cured at 175 ° C. for 8 hours.

The cases using the tablets obtained in Examples 2 and 3 are referred to as Examples 4 and 5, and the cases using the tablets obtained in Comparative Examples 1 and 2 are referred to as Comparative Examples 3 and 4, respectively. ..

Using the various test pieces thus obtained, the flexural modulus, flexural strength, linear expansion coefficient, glass transition temperature and appearance of the cured product were examined by the following methods. The results are shown in Table 1.

The flexural modulus is measured according to JIS K 6911,
The tensile tester manufactured by Instron was used, and the flexural strength was also measured according to JIS K 6911 using the same tester as the flexural modulus.

The coefficient of linear expansion was measured by TMA manufactured by Perkin Elmer at a temperature rising rate of 2.5 ° C./minute, and the glass transition temperature was also measured using the same apparatus as that for measuring the coefficient of linear expansion.
The heating rate was 2.5 ° C./min.

The state of the surface of the cured product was visually observed and evaluated according to the criteria shown in Table 1.

Further, a heat resistance reliability test, a humidity resistance reliability test and a cold heat shock resistance test were conducted by the following methods using various reliability evaluation monitor chips. The results are shown in Table 1.

The heat resistance reliability test was carried out by leaving the monitor chip in the air at 250 ° C. and measuring the time until a defect occurred in the monitor chip.

For the moisture resistance reliability test, 20 monitor chips were used.
PCT (Pressure Cooker Test) 130 ℃, 2.7 bar
After leaving it for 1000 hours, it was evaluated by evaluating the number of defective monitor chips generated.

In the cold and thermal shock resistance test, 20 monitor chips were used, and the condition of leaving them at −65 ° C. for 30 minutes and then at 150 ° C. for 30 minutes was set as one cycle, and this cycle was repeated 200 times. The number was evaluated.

[0066]

[Table 1] As can be seen from the results shown in Table 1, the examples have higher flexural modulus, higher bending strength at high temperature, and less decrease in strength at high temperatures as compared with the comparative examples, and have excellent appearance and heat resistance. Excellent results are also shown in tests, humidity resistance reliability tests, and thermal shock resistance tests.

[0067]

As described above, the inorganic filler coated with the polyimide resin of the present invention has good adhesion to the surface of the inorganic filler, and the polyimide itself of the coating layer has heat resistance. The layers are thick compared to those treated with conventional silane coupling agents. Next, the resin composition containing the inorganic filler coated with the polyimide resin has a high adhesiveness between the polyimide resin and the resin to be the matrix, and the filler coated with the polyimide resin has the above-described characteristics, It can sufficiently relax the thermal stress generated by cold heat shock, maintains high adhesion even at high temperatures, has high high-temperature strength and excellent heat resistance.

From the above, the semiconductor device encapsulated with the resin composition becomes a semiconductor device such as an IC or LSI which is excellent in heat resistance, moisture resistance, and thermal shock resistance.

[Procedure amendment]

[Submission date] December 6, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

The resin composition provides a resin composition for semiconductor encapsulation which is excellent in crack resistance and moisture resistance and is stable. Since the difference in the coefficient of thermal expansion between the resin matrix such as epoxy and the inorganic filler still remains, a large stress is generated at the interface. In addition, since the heat resistance of the silane coupling agent used as the adhesion improving component is low, the adhesion at the interface after high temperature treatment is low, and the film thickness is very thin, so that the resin matrix and the inorganic filler are It was found that the stress generated at the interface cannot be sufficiently reduced due to the difference in the coefficient of thermal expansion, the mechanical strength of the resin composition is lowered, and a package crack is generated in the assembly process of the resin sealing element.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location H01L 23/31 // C08G 73/10 NTE 9285-4J (72) Inventor Yasushi Yamamoto Tsukaguchi Honcho, Amagasaki 8-1-1, Mitsubishi Electric Corporation Materials Research Center

Claims (3)

[Claims] 1. A compound represented by the general formula (I): (In the formula, R ¹ is an organic group having 1 to 5 carbon atoms, and R ² and R ³ are 2
An organic filler having a valent organic group, R ⁴ is a tetravalent organic group, and n is an integer of 2 or more), and an inorganic filler having a coating layer that is imidized after being coated with a terminal silicon-modified polyamic acid compound An inorganic filler coated with a polyimide resin. 2. A resin composition containing an inorganic filler coated with the polyimide resin according to claim 1. 3. A semiconductor device encapsulated with the resin composition according to claim 2.