JPH03290421A - Production of resin for encapsulation of semiconductor - Google Patents

Abstract

PURPOSE:To obtain the subject resin having excellent moistureresistance, etc., by reacting a specific dihydropolysiloxane with a specific allylated phenolic aromatic hydrocarbon resin under specific condition and reacting the obtained allylated polysiloxane with a polymaleimide under specific condition. CONSTITUTION:The objective resin having high glass-transition point, excellent compatibility and low stress generation can be produced by reacting a dihydropolysiloxane of formula I (R1 and R2 are 1-4C alkyl or phenyl; n is 1-100) with an allylated phenolic aromatic hydrocarbon resin of formula II (R3 and R4 are H or methyl; a, b, c and d are percentages of respective structural units and are preferably 10<=a<=70, 10<=b<=40 and 10<=d<=70) at an allyl/ hydroxyl ratio of (2-10)/1 until the reaction ratio of hydrosilyl group reaches >=80% and reacting 30-300 pts.wt. of the obtained allylated polysiloxane with 100 pts.wt. of a polymaleimide until the melting point of the produced resin reaches 50-120 deg.C.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to the production of a resin for semiconductor encapsulation that has a high glass transition point (hereinafter referred to as Tg), excellent moisture resistance, compatibility, and low stress characteristics. It is about the method.

(Prior Art) In recent years, epoxy resin compositions have been commonly used for sealing semiconductor elements such as ICs, LSIs, transistors, diodes, and electronic circuits from the viewpoint of characteristics, cost, and the like.

However, as electronic components are becoming more mass-producible, more highly integrated, and more surface-mounted, demands on sealing resins are becoming more severe.

In particular, chips become larger due to higher integration, packages become thinner, and solder immersion (200 to 300°C) during surface mounting is required.
), which makes it easy for devices to crack, and in order to improve reliability, it is strongly desired that resins for semiconductor encapsulation have low stress characteristics and heat resistance.

Epoxy resin is currently the mainstream resin for semiconductor encapsulation, but there are limits to its improvement in terms of heat resistance as long as epoxy resin is used, and it is difficult to obtain a highly reliable product after solder immersion during surface mounting. Not yet.

In order to cope with these solder heat resistance, it is desired that the resin properties be low stress and high Tg that is higher than the solder bath temperature.

Maleimide resin is attracting attention as a resin with high heat resistance that can replace epoxy resin, but amine-modified maleimide resin obtained by the reaction of bismaleimide and aromatic diamine has excellent heat resistance during drying. but,
It has a high water absorption rate, and cracks occur when immersed in solder when moisture is absorbed, resulting in poor reliability.

Other maleimide resins include examples in which polymaleimide and alkenyl phenols or alkenyl phenyl ethers are reacted in the presence of a polymerization catalyst (Japanese Patent Application Laid-Open No.
2-994.58-117219.61-95012.
62-11716.63-230728), but like the amine-modified maleimide resin, the cured product is hard, so it has the disadvantage of poor low stress properties.

Attempts have been made to add various silicone compounds as a measure to improve low-stress properties, but they have significantly poor compatibility, reduced strength, high water absorption, lack moisture resistance and reliability, and have many practical problems. remain.

(Problems to be Solved by the Invention) The object of the present invention is to have good compatibility, excellent moisture resistance, low stress characteristics, and high heat resistance without deteriorating general characteristics, and to have solder immersion resistance. It is an object of the present invention to provide a method for producing a resin for semiconductor encapsulation that has excellent subsequent reliability.

(Means for Solving the Problems) The present invention comprises (A) 100 parts by weight of polymaleimide, and (B)
) A dihydro polysiloxane represented by the following formula CI), and (k, R2: alkyl group having 1 to 4 carbon atoms or phenyl group n: 1 to 100) an allylated phenol represented by the composition of the following formula (II)・Aromatic hydrocarbon resin (R3, L: -H or methyl group 0 < a, b, c, d < 100 a+b+c
+d=100a, b, c, d indicate the percentage of each composition.

) Allyl group/hydroxylyl group (Si-H) ratio is 2/
1 to 10/1 and 30 to 300 parts by weight of an allylated polysiloxane obtained by reacting until the reaction rate of the hydrosilyl group reaches 80% or more.
This is a method for producing a resin for semiconductor encapsulation, characterized in that the reaction is carried out until the temperature reaches 0°C.

(Function) Specific examples of the polymerimide used in the present invention include N,N'-m-phenylene bismaleimide, N,
N'-p-phenylene bismaleimide, N, N'-m-
Toluylene bismaleimide, N,N'-4,4'-biphenylene bismaleimide, N,N'-4,4'-(3
, 3'-dimethyl-biphenylene bismaleimide, N,
N'-4,4'-(3,3'-dimethyldiphenylmethane)bismaleimide, N,N'-4,4'-(3,3'
-jethyldiphenylmethane] bismaleimide, N, N
'-4,4'-diphenylmethane bismaleimide, N,
N'-4,4'-diphenylpropane bismaleimide,
N,N''-4,4'-diphenyl ether bismaleimide, N,N'-3,3'-diphenylsulfone bismaleimide, N,N'-4,4'-diphenylsulfone bismaleimide, general formula (m) or Examples include polyfunctional maleimide represented by (IV).There is no problem even if two or more types of these are contained.

(R5 knee H, alkyl group or phenyl group 0<i
<10) (0<j<10) The dihydro polysiloxane used in the present invention is a polysiloxane represented by the following formula CI), and its degree of polymerization n
ranges from 1 to 100.

(R engineering, R2: alkyl group having 1 to 4 carbon atoms or phenyl group) If the degree of polymerization is greater than 100, the compatibility will decrease. In addition, in the reaction with the allyl group, trifunctional or higher functional polyhydro-polysiloxane may be used in combination as long as it does not cause gelation.

Allylated phenol/aromatic hydrocarbon resin is a phenol/aromatic hydrocarbon resin obtained by reacting toluene resin, xylene resin, or xylylene dialkyl ether with phenol or phenol resin, such as phenol-modified xylene resin (Mitsubishi Gas Chemistry ■ Acid dicanol p
-too) or phenolic aralkyl resin (Mitsui Toatsu Co., Ltd.'s Millex The resin contains parts with each structure in the overall ratio of a, b, c, and d.

(R3, R4: -H or methyl group 0<a, b, C, d<too and a+b+c+d=10
0a, b, c, d indicate the percentage (%) of each composition) Preferably, 10≦a≦70, lO≦b≦40, lO≦d
≦70 is good.

Component a is effective in improving heat strength and lowering water absorption, but in the resin production reaction with polymaleimide,
Since there is almost no reaction, if the amount is too large, the resin will not solidify, resulting in poor compatibility and workability.

Component b is an important component that reacts with maleimide groups in the resin production reaction with polymaleimide and improves the compatibility between polymaleimide and polysiloxane. However, if the amount is too large, the number of phenolic hydroxyl groups in the cured product increases, resulting in an increase in water absorption, which is not preferable.

The d component has a remarkable effect on lowering the water absorption rate and improving reliability. However, if the amount is too large, the reactivity in the resin production reaction and curing reaction will deteriorate, making it unsuitable for use as a sealing material.

The ratio of allyl group/hydroxylyl group (Si-H) in the reaction between dihydro polysiloxane and allylated phenol/aromatic hydrocarbon resin is preferably 271 to 10/1.

If the number of allyl groups is too small, compatibility with polymaleimide,
Moldability and mechanical strength of the cured product deteriorate. If it is too large, the amount of polysiloxane will be reduced and the low stress properties will not be improved.

The reaction conditions are not particularly limited, but for example, in the presence of chloroplatinic acid in a toluene solvent at 90°C to
The reaction is carried out at a reflux temperature, and after the reaction, the converted platinic acid is removed by extraction and washing with water/toluene, and the toluene is distilled off to obtain an allylated polysiloxane.

In the reaction, the reaction rate of hydrosilyl group (Si-H) was 80%.
It is best to do this until it reaches the above level. If the reaction rate is less than 80%, free polysiloxane components will ooze out into the molded product.
This may deteriorate the appearance or cause mold cloudiness.

The reaction between polymaleimide and allylated polysiloxane is
Although the reaction conditions are not particularly limited, for example, the reaction is carried out by heating allylated polysiloxane to 130 to 150°C and adding polymaleimide thereto. The amount of allylated polysiloxane is preferably 30 to 300 parts by weight per 100 parts by weight of the polymaleimide.

If it is too small, low stress characteristics cannot be obtained. If it is too large, the mechanical strength and Tg will decrease and cracks will occur during solder immersion. The end point of the reaction is when the melting point of the obtained resin is 50 to 120 degrees.
React until it reaches the range of C. In addition, in order to confirm the end point of the reaction, a small amount of resin is taken out from the reaction system, cooled, and the melting point is measured and confirmed.

In addition, in order to make a molding material using the obtained resin, a curing accelerator, epoxy resin, inorganic filler, lubricant, flame retardant, mold release agent, silane coupling agent, etc. are appropriately mixed and added as necessary. It can be made into a material by heating and kneading.

A general method for manufacturing the resin composition for semiconductor encapsulation of the present invention as a molding material is to add various additives to these essential components and mix the composition uniformly, and then subject the composition to cross-contact treatment using a niegu, hot roll, etc. After cooling, it is crushed to make a molding material.

If the obtained molding material is used for encapsulating semiconductors, high T
In addition, it is possible to obtain a resin composition for semiconductor encapsulation which has excellent low stress characteristics and is highly reliable.

(Example) Synthesis 1 of 1-allylated phenol/aromatic hydrocarbon resin Synthesis Example 1 Potassium hydroxide and , a mixed solvent of water/acetone (1/1) was added and dissolved, and the phenol-modified xylene resin was added and dissolved.

The solution was heated, allyl bromide was added, and the mixture was allowed to react under reflux for 3 hours. Thereafter, the mixture was neutralized with hydrochloric acid, allyl bromide that had not reacted with acetone was distilled off, and 1 liter of toluene was added. The mixture was transferred to a separating funnel, washed with water three times, and the solvent was removed using an evaporator.

Further, heat treatment was performed at 175° C. for 14 hours to obtain an allylated phenol aromatic hydrocarbon resin. The composition of the product is shown in Table 1.

Reference Example 1 The phenol-modified xylene resin in Synthesis Example 1 was replaced with a phenol resin, and the reaction was carried out in the same manner.

Examples 1-2 A reaction vessel equipped with a stirrer, a reflux condenser and a thermometer was
The allylated phenol/aromatic hydrocarbon resin of Synthesis Example 1 and toluene were added according to the recipe in Table 2, uniformly dissolved, and then the isopropanol chloroplatinate solution was added. Dihydropolysiloxane was added to this and reacted at 90°C for 2 hours. After the reaction, the mixture was transferred to a separating funnel, washed with water three times, and the solvent was removed using an evaporator to obtain allylated polysiloxane. The reaction rate of hydrosilyl group is 8 in both cases.
It is 0% or more.

Next, the obtained allylated polysiloxane was placed in a reaction vessel equipped with a stirring device, a vacuum distillation device, and a thermometer according to the recipe in Table 3, heated to 130°C, and then the polymaleimide was added, and the pressure was reduced. The reaction was carried out under (approximately 20 mmHg). The obtained silicone-modified maleimide resin is homogeneous and
The melting points are shown in Table 3.

Comparative Example 1 A reaction was carried out in the same manner as in Example 1, except that the amount of the allylated phenol aromatic hydrocarbon resin in Example 1 was reduced and the amount of dihydropolysiloxane was increased. The obtained silicone-modified maleimide resin was heterogeneous as shown in Table 3, and an oily silicone component exuded.

Comparative Example 2 A similar reaction was carried out using dihydropolysiloxane having a high degree of polymerization (n). The compatibility was very poor, and the resulting silicone-modified maleimide resin was heterogeneous, with oily silicone components exuding out.

Comparative example 3 Using Reference Example 1, a reaction was carried out in the same manner as in Example 1.

Examples 3-4 According to the formulations shown in Table 4, silica powder, curing accelerator,
Aminosilane, a coloring agent, and a mold release agent were added, and the mixture was kneaded with hot rolls to obtain a molding material. The obtained molding material was molded by transfer molding at 180° C. for 93 minutes to obtain a glossy molded product without blisters. Add 1 more of this molded product
After curing at 80°C for 18 hours, the properties were evaluated. The results are shown in Table 4.

The molding materials of Examples 3 and 4 using the resins of Examples 1 and 2 have a lower flexural modulus at room temperature, lower stress, and lower internal stress than the comparative example that does not contain silicone. Moreover,
It has a high glass transition temperature, high bending strength at 260°C, excellent heat resistance and solder crack resistance, and low water absorption.

Comparative Examples 5-8 For comparison with Examples 3-4, molding materials were similarly prepared and molded using the formulations shown in Table 4.

Comparative Example 5 used the resin of Comparative Example 1 (allyl group/hydrosilyl group = 171), but the mold was cloudy, resulting in poor moldability and poor appearance of the molded product, and low bending strength.

Comparative Example 6 uses the aromatic hydrocarbon-free phenolic resin of Reference Example 1, and has high bending strength and a high glass transition temperature, but has a high water absorption rate and therefore does not have sufficient solder crack resistance.

Comparative Example 7 has almost the same composition as Example 3, but was simply mixed at the time of blending. Similar to Comparative Example 5, the appearance of the molded product was poor and the bending strength was low.

Comparative Example 8 does not contain polysiloxane. The appearance, bending strength, and glass transition temperature of the molded product are as good as those in Comparative Example 6, but the bending elastic modulus and water absorption are large;
Solder crack resistance is not sufficient.

It has good properties, low stress, and excellent heat cycle resistance, making it an excellent and extremely reliable resin composition for semiconductor encapsulation.

(Effects of the Invention) The molded product using the resin for semiconductor encapsulation produced by the manufacturing method of the present invention has a high Tg and is excellent in moisture resistance and strength under heat, so the solder crack resistance of the encapsulated body is the best. Table procedure amendment (1) Amend the claims as per the attached sheet.

July 11, 1990

Claims (1)

[Claims] (1) (A) 100 parts by weight of polymaleimide, (B) dihydro polysiloxane represented by the following formula [I], ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・〔I
] (R_1, R_2: alkyl group having 1 to 4 carbon atoms or phenyl group n: 1 to 100) allylated phenol/aromatic hydrocarbon resin represented by the composition of the following formula [II] ▲ mathematical formula, chemical formula, table etc.▼・・・・・・[II] (R_3, R_4: -H or methyl group 0<a, b, c, d<100 and a+b+c+d=10
0a, b, c, and d indicate the percentage of each composition. ) Allyl group/hydroxylyl group (Si-H) ratio is 2/1 to 10/
1, allylated polysiloxane 30 to 30 obtained by reacting until the reaction rate of the hydrosilyl group reaches 80% or more
1. A method for producing a resin for semiconductor encapsulation, characterized by reacting 0 parts by weight with 0 parts by weight until the melting point of the resulting resin reaches 50 to 120°C.