JPH01249825A - Resin composition for sealing and production thereof - Google Patents

Abstract

PURPOSE:To provide the subject composition having excellent low stress characteristics, moisture resistance and moldability and high reliability, by comprising a novolak type phenol resin, an inorganic filler and a resin obtained by dispersing a silicone compound and an oil-absorbing compound in an epoxy resin. CONSTITUTION:(A) An epoxy resin is melted and the melted epoxy resin is mixed and thermally reacted with (B) a silicone compound (e.g., silicone rubber) having a reactivity with the component A to homogeneously disperse the component A in the component B. (C) An oil-absorbing compound (e.g., norbornere rubber) is further dispersed and mixed with the above dispersion product and the resultant resin mixture comprising the components A, B and C is ground together with (D) a novolak type phenol resin. (E) An inorganic filler (e.g., silica powder) is added to and mixed with the ground product and the mixture is kneaded with heating, solidified with cooling and subsequently ground to provide the objective composition comprising the components B and C dispersed in the component A and the components D and E.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a resin composition for encapsulating electronic or electrical parts, which has excellent low stress characteristics, moisture resistance, and moldability, and its production. Regarding the method.

(Prior Art) Conventionally, electronic components such as diodes, transistors, and integrated circuits have been sealed using a thermosetting resin. This resin sealing is economically advantageous compared to hermetic sealing methods using glass, metal, or ceramic, and is therefore widely put into practical use. Among thermosetting resins used for resin sealing, epoxy resin compositions are most commonly used. Epoxy resin compositions use curing agents such as acid anhydrides, aromatic amines, and novolac-type phenolic resins. It is widely used as a semiconductor encapsulation material because it has superior moldability and moisture resistance, is non-toxic, and is inexpensive compared to the previously used materials.

(Problems to be Solved by the Invention) However, epoxy resin compositions using novolak-type phenolic resin as a curing agent have the disadvantage that they shrink during molding and curing, applying stress to semiconductor devices and deteriorating the reliability of the devices. be. When a molded article using such a resin composition is subjected to a hot/cold cycle test, bonding wire opens, resin cracks, pellet cracks, etc. occur, resulting in the problem that the molded article cannot function as an electronic component. In addition, there is a method of adding a third component to reduce stress in the resin composition, but the third component forms secondary aggregates and cannot be uniformly dispersed in the resin composition, resulting in low stress. There was a drawback that variations in characteristics occurred. Furthermore, attempts have been made to reduce stress by adding silicone compounds, but this has had drawbacks such as mold staining, mold releasability, and other deterioration in moldability.

The present invention was made to eliminate the above-mentioned drawbacks, and has no variation in low stress properties, excellent moisture resistance, moldability, and hot/cold cycle tests, and maintains the characteristics of conventional epoxy resin compositions. The present invention aims to provide a highly reliable sealing resin composition and a method for producing the same.

[Structure of the Invention] (Means for Solving the Problems) As a result of extensive research in an attempt to achieve the above object, the present inventors developed a heating reaction dispersion method for silicone compounds that are reactive with epoxy resins. The inventors have discovered that by using a resin in which a compound with oil absorption is dispersed and mixed, a resin composition with uniform low stress properties, excellent moisture resistance, and moldability can be obtained, and the present invention has been completed. It is something. That is, the present invention comprises (A) reacting and dispersing a silicone compound having reactivity with (B) the epoxy resin in the epoxy resin;
(C) A resin prepared by dispersing and mixing an oil-absorbing compound [(A
)±(B)÷(C)], <D) A novolac type phenol resin and (E) an inorganic filler. In addition, (A) the epoxy resin is melted, (B) a reactive silicone compound is added thereto, the mixture is heated and uniformly dispersed, and then (C) the oil-absorbing compound is dispersed and mixed in the resin [(A) + (B
) + (C) and (D) a novolac type phenolic resin are crushed, then (F,) an inorganic filler is added and mixed, further heated and kneaded, and then cooled and solidified and crushed. This is a method for producing a stopper resin composition.

The epoxy resin (A) used in the present invention is not particularly limited in terms of molecular structure and molecular weight as long as it is a compound having at least two epoxy groups in its molecule. Can be broadly encompassed. Examples include aromatic resins such as bisphenol type, alicyclic resins such as cyclohexane derivatives, and epoxy novolak resins represented by the following general formula.

(However, in the formula, R1 represents a hydrogen atom, a halogen atom, or an alkyl group, R2 represents a hydrogen atom or an alkyl group, and n represents an integer of 1 or more). These epoxy resins can be used alone or in combination.
Used as a mixture of more than one species.

Examples of the reactive silicone compound (B) used in the present invention include silicone oil having a functional group reactive with epoxy resin, silicone gel cured by heating or at room temperature, silicone rubber, etc., which are generally commercially available. can be widely used. These compounds may be used alone or as a mixture of two or more.

The oil-absorbing compound (C) used in the present invention may be any porous organic rubber such as norbornene rubber, acrylonitrile-butadiene-styrene copolymer resin, or an inorganic substance such as carbon black, and is not particularly limited. do not have.

The blending ratio of the reactive silicone compound is determined by the resin [
It is desirable to contain 0.1 to 60% by weight of (A>+ <8) + (c)]. If the proportion is less than 0.1% by weight, it will not be effective in withstanding low stress and tin-based cycles. Moreover, if it exceeds 60% by weight, it is not preferable because it cannot be uniformly reacted and dispersed in the epoxy resin. In addition, the compounding ratio of the oil-absorbing compound is the resin [(A) + (B
)±(C)] is desirably contained in an amount of 0.1 to 60% by weight.

If the proportion is less than 0.1% by weight, there is no effect of adsorbing unreacted silicone components, and if it exceeds 60% by weight, uniform dispersion and mixing cannot be achieved, which is not preferable.

In addition, the total amount of the reactive silicone compound and the oil-absorbing compound [(B) + (C)] is the resin [(A
) + CB) + (c)] o, i ~ 80% by weight
It is preferable that If the proportion is less than 0.1% by weight, it has no effect on low stress, tin group cycle, or adsorption.
If it exceeds 80% by weight, the viscosity increases and moldability becomes poor, which is not preferable.

A method for uniformly dispersing a reactive silicone compound and an oil-absorbing compound in an epoxy resin is carried out as follows. The epoxy resin is placed in a device (container) that can be heated to a temperature above the melting point of the epoxy resin.
After heating to a temperature higher than the melting point to completely molten liquid, a reactive silicone compound is added and stirred for 10 minutes or more at a temperature of 120° C. or higher to uniformly react and disperse. Next, an oil-absorbing compound is added and stirred for 10 minutes or more, preferably at a temperature of 120°C or higher, to adsorb unreacted silicone compounds and form the resin [(A) + (B) + (C).
], this resin [(A)+(B)+(C)
] The blending ratio is 1 to 50 to the entire resin composition.
It is desirable to contain % by weight.

If the proportion is less than 1% by weight, it will not be effective in reducing stress, and 50f! If it exceeds 1%, the reactive silicone compound will not be uniformly dispersed and the viscosity will increase, which is not preferable.

The <D) novolak type phenolic resin used in the present invention includes novolak type phenol resins obtained by reacting phenols such as phenol and alkylphenols with formaldehyde or paraformaldehyde, and modified resins thereof, such as epoxidized or butylated novolacs. Type.

Examples include phenol resins, and these resins may be used alone or as a mixture of two or more.

The blending ratio of the novolak-type phenolic resin is determined by the equivalent ratio of the epoxy group (a) of the epoxy resin and the phenolic hydroxyl group (d) of the novolak-type phenol resin [1a], which will be described later.
＞/(d)] is preferably within the range of 0.1 to 10. If this equivalent ratio is less than 0.1 or exceeds 10, moisture resistance, molding workability, and electrical properties of the cured product will deteriorate. , both cases are unfavorable. Therefore, it is limited within the above range.

Examples of the inorganic filler (E) used in the present invention include silica powder, alumina, antimony trioxide, talc, calcium carbonate, titanium white, clay, mica, red iron oxide, glass fiber, and carbon fiber, which may be used alone or Use a mixture of two or more. Among these, silica powder and alumina are particularly preferred. The blending ratio of the inorganic filler is 25 to 25% of the total resin composition.
It is desirable to contain 90% by weight, and the proportion is 25%.
If it is less than 90% by weight, it will have no effect on moisture resistance, heat resistance, mechanical properties, or moldability, and if it exceeds 90% by weight, it will have large coverage and poor moldability, making it unsuitable for practical use.

The sealing resin composition of the present invention contains as essential components a resin obtained by reaction-dispersing a silicone compound having reactivity with an epoxy resin, dispersing and mixing a compound having oil-absorbing properties, a novolac type phenol resin, and an inorganic filler. If necessary, release agents such as natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, paraffins, chlorinated paraffins, bromotoluene, hexabromobenzene, antimony dioxide, etc. Flame retardants, silane coupling agents, various curing accelerators, etc. can be appropriately blended.

In the method for producing the sealing resin composition of the present invention, a resin in which a reactive silicone compound is heat-reacted and dispersed in an epoxy resin, and an oil-absorbing compound is further uniformly dispersed and mixed therein may be used. The manufacturing method is not limited, however, it is usually manufactured in a similar manner to clothing.

Use a device (container) that can be heated to a temperature above the melting point of the epoxy resin, such as an all-purpose mixer, a powerful kneader, or a heating reaction vessel, and charge the epoxy resin into the container and heat it above the melting point to completely melt it. After that, a reactive silicone compound is added and stirred at a temperature of 120° C. or higher for 10 minutes or more to uniformly react and disperse the mixture.

Thereafter, the oil-absorbing compound is stirred at a temperature of 120'C or more for 10 minutes or more to produce a resin comprising a silicone compound that is reactive with the epoxy resin and an oil-absorbing compound. This resin and novolac type phenolic resin are crushed, and then the raw material composition including the inorganic filler and other components selected at a predetermined composition ratio is sufficiently uniformly mixed using a mixer, etc., and then heated using a hot roll, extruder, or kneader. A sealing resin composition is produced by heating and kneading the mixture, waiting for cooling and solidifying, and then pulverizing it into an appropriate size. Above, we have explained a manufacturing method in which a reactive silicone compound and an oil-absorbing compound are dispersed in an epoxy resin, and then other components are blended. The resin composition for sealing of the present invention thus produced can be applied to sealing, coating, insulation, etc. of electronic or electrical parts.

(Function) A reactive silicone compound is uniformly reacted and dispersed in an epoxy resin, an unreacted reactive silicone compound is adsorbed with an oil-absorbing compound, and then dispersed and mixed in a novolac type phenol resin. This eliminates variations in low stress properties, and since no reactive silicone compounds remain, there are no negative effects on moldability such as mold stains or poor mold release properties. disappears.

(Example) The present invention will be specifically explained using Examples.
The invention is not limited to the following examples. In the following Examples and Comparative Examples, "%" means "% by weight".
” means.

Preparation of resin 75% of a cresol novolatile epoxy resin (epoxy equivalent: 215) was placed in a universal mixer and heated to 120°C to completely melt it. Next, 20% of reactive silicone rubber was added and reacted with stirring for 1 hour, and then 5% of polynorbornene rubber was added and mixed with stirring for 30 minutes to produce a dispersed resin (hereinafter referred to as E-3 resin).

Example I E-3l! 20% l fat and novolak type phenolic resin (
Phenol equivalent (107) 10% was crushed using screen 21n of Yalla crusher, mixed with 65% of fused silica powder and 5% of other ingredients at room temperature, further kneaded at 90-100°C, cooled, and then crushed for sealing. A resin composition was produced. This resin composition was transfer-injected into a mold heated to 175°C and cured to produce a molded product (sealed product).
Other tests were conducted and the results are shown in Table 1. The sealing resin composition of the present invention was excellent in moisture damage cycle, moisture resistance, and low stress characteristics, and had little mold staining, and the remarkable effects of the present invention were recognized.

Example 2 18% E-3 resin and novolac type phenol vI4 fat (
Amount of phenol (107) 12% was pulverized with a screen 2ffi1N of a Yalla pulverizer, 65% fused silica powder and 5% other components were blended, and a sealing resin composition was prepared in the same manner as in Example 1. ! I left it behind. In addition, molded products were made in the same manner and various tests were conducted, and the results are shown in Table 1. Similar to Example 1, remarkable effects of the present invention were observed.

Comparative Example 1 Ri I/sol novolac epoxy resin (epoxy equivalent 2
15) 15%, novolac type phenolic resin (i 107 per phenol) 10%, reactive silicone compound 4%, polynorbornene rubber 1%, fused silica powder 6
5% and other ingredients are mixed at room temperature, and further 90%
After kneading and cooling at ~100°C, the mixture was pulverized to leave a sealing resin composition. Next, molded articles were made using this resin composition, and various properties were tested in the same manner as in the examples.The results are shown in Table 1.

Comparative Example 2 Cresol novolak epoxy resin (Evogishi 1 2
15) To 20%, 10% novolac type phenol resin (phenol equivalent: 107), 65% fused silica powder and 5% other components were added in the same manner as in Comparative Example 1 to prepare a sealing resin composition, and a molded article was prepared. were prepared and tested for various properties in the same manner, and the results are shown in Table 1.

Table 1 (units) *1: The number of cracks is determined by embedding a 25 x 25 x lllmn copper plate in the bottom of a 30 x 25 x 5vn molded product, and placing it in a constant temperature oven at -40°C and 200°C for 30 minutes each.
The cracks in the resin were investigated after 15 cycles were repeated.

*2: Using the sealing resin composition, an electrical component having two aluminum wirings was transfer-molded at 170°C for 3 minutes, and then cured at 180°C for 8 hours.

For 100 sealed electrical components thus obtained, 120
A #4 humidity test was conducted in high-pressure steam of 'C' to evaluate the time required for 50% wire breakage (defect occurrence) due to aluminum corrosion.

*3: A commercially available strain gauge was attached to the island part of the DIP16 bin lead frame, and the strain was measured after curing at 180''C for 8 hours.

Tree 4: Transfer molding was performed continuously for 500 shots at 175'C for 2 minutes using a DIP16 pino mold, and visually judged.

[Effects of the Invention] As is clear from the above explanation and Table 1, according to the sealing resin composition and the method for producing the same of the present invention, a reactive silicone compound is heated and melted into an epoxy resin. Then, by using a resin in which oil-absorbing compounds are dispersed and mixed, it has excellent low stress properties with no variation, moisture resistance, tin base cycle, and moldability, and has the characteristics of conventional epoxy resin compositions. was obtained that retained the Excellent reliability can be imparted to electronic components or electrical components using this resin composition.

Claims (1)

[Claims] 1. A resin in which (A) an epoxy resin is reacted and dispersed with (B) a silicone compound that is reactive with the epoxy resin, and (C) a compound that has oil absorption properties is further dispersed and mixed [
(A)+(B)+(C)], (D) a novolac type phenolic resin, and (E) an inorganic filler as essential components. 2. Add a reactive silicone compound to the resin [(A)
+(B)+(C)] 0.1 to 60% by weight of the sealing resin composition according to claim 1. 3. A compound having oil absorption property is added to a resin [(A)+(B)+
(C)] 0.1 to 60% by weight of the sealing resin composition according to claim 1 or 2. 4. The total amount of the reactive silicone compound and the oil-absorbing compound [(B)+(C)] was added to the resin [(A)+
The sealing resin composition according to any one of claims 1 to 3, which contains 0.1 to 80% by weight based on (B)+(C)]. 5. The sealing according to any one of claims 1 to 4, which contains 1 to 50% by weight of resin [(A)+(B)+(C)] based on the entire resin composition. Resin composition for use. 6. The sealing resin composition according to any one of claims 1 to 5, which contains (D) an inorganic filler in an amount of 25 to 90% by weight based on the entire resin composition. 7. Equivalence ratio of the epoxy group (a) of the epoxy resin and the phenolic hydroxyl group (d) of the novolac type phenolic resin [
(a)/(d)] is within the range of 0.1 to 10, the sealing resin composition according to any one of claims 1 to 6. 8. (A) Melt the epoxy resin, add (B) a silicone compound that is reactive with the epoxy resin, and homogeneously disperse it by heating reaction. (A)+(B)+(C)] and (D
) Novolak type phenolic resin is crushed, and then (E
) A method for producing a sealing resin composition, which comprises adding and mixing an inorganic filler, further heating and kneading, and then cooling, solidifying, and pulverizing.