JP2857216B2 - Method for producing resin for semiconductor encapsulation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is to produce a resin for semiconductor encapsulation having a high glass transition point (hereinafter referred to as Tg), excellent moisture resistance, excellent compatibility, and excellent low stress characteristics. It is about the method.

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

However, the trend toward mass production of electronic components, high integration, and surface mounting has been progressing, and accordingly, the demand for sealing resin has become strict.

In particular, cracks are likely to occur in the equipment due to the increase in size of chips due to high integration, thinning of packages, and solder immersion (200 to 300 ° C) during surface mounting. Low stress characteristics and heat resistance are strongly desired as a stopping resin.

Epoxy resin is currently the mainstream resin for semiconductor encapsulation, but in terms of heat resistance, improvement is limited as long as epoxy resin is used, and a highly reliable resin after solder immersion during surface mounting can be obtained. Not.

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

As a resin having high heat resistance instead of an epoxy resin, a maleimide resin has been attracting attention, but an amine-modified maleimide resin obtained by a reaction between a bismaleimide and an aromatic diamine has excellent heat resistance during drying. However, there is a disadvantage that the water absorption is large, cracks are generated by solder immersion during moisture absorption, and the reliability is poor.

Other examples of the maleimide resin include an example in which a polymaleimide is reacted with an alkenyl phenol or an alkenyl phenyl ether in the presence of a polymerization catalyst (Japanese Unexamined Patent Application Publication No.
52-994, 58-117219, 61-95012, 62-11716, 63-230
No. 728), but there is a drawback that the cured product is inferior in low stress characteristics because the cured product is hard like the amine-modified maleimide resin.

Attempts have been made to add various silicone compounds to improve low-stress properties, but compatibility is remarkably poor, strength is reduced, water absorption is large, moisture resistance and reliability are lacking, and there are practical problems. Many remain.

(Problems to be Solved by the Invention) The object of the present invention is to have good compatibility, without deteriorating general properties, excellent in moisture resistance and low stress properties,
Another object of the present invention is to provide a method for producing a resin for semiconductor encapsulation, which has high heat resistance and very excellent reliability after solder immersion.

(Means for Solving the Problems) The present invention provides (A) 100 parts by weight of polymaleimide,
(B) a dihydropolysiloxane represented by the following formula [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 following formula [II] (R ₃ , R ₄ : -H or methyl group 0 <a, b, c, d <100 and a + b + c + d = 100 10 ≦ a ≦ 70, 10 ≦ b ≦ 40, 10 ≦ d ≦ 70 a, b, c, d indicates the percentage of each structural unit.) The ratio of allyl group / hydrosilyl group (Si-H) is 2/1 to 10/1.
And reacting 30 to 300 parts by weight of an allylated polysiloxane obtained by reacting until the reaction rate of the hydrosilyl group becomes 80% or more, until the melting point of the produced resin becomes 50 to 120 ° C. This is a method for producing a resin for semiconductor encapsulation.

(Function) Specific examples of the polymaleimide used in the present invention include N, N'-m-phenylenebismaleimide, N, N '
-P-phenylenebismaleimide, N, N'-m-toluylenebismaleimide, N, N'-4,4'-biphenylenebismaleimide, N, N'-4,4 '-[3,3'-dimethyl -Biphenylene] bismaleimide, N, N'-4,4 '-[3,3'-
Dimethyldiphenylmethane] bismaleimide, N, N'-
4,4 '-[3,3'-diethyldiphenylmethane] bismaleimide, N, N'-4,4'-diphenylmethanebismaleimide, N, N'-4,4'-diphenylpropanebismaleimide, N, N'-4,4'-diphenylether bismaleimide, N, N'-3,3'-diphenylsulfonebismaleimide, N, N'-4,4'-diphenylsulfonebismaleimide, of the general formula (III) or (IV) And the like. These may be contained in two or more kinds.

The dihydropolysiloxane used in the present invention is a polysiloxane represented by the following formula [I], and the degree of polymerization n is in the range of 1 to 100.

(R ₁ , R ₂ : alkyl group having 1 to 4 carbon atoms or phenyl group) When the degree of polymerization is larger than 100, the compatibility is reduced. In the reaction with the allyl group, a polyhydro-polysiloxane having three or more functional groups may be used in combination as long as gelling does not occur.

The 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, for example, phenol-modified xylene resin (Mitsubishi Gas) Nikanol P-100 (manufactured by Chemical Co., Ltd.) or phenol aralkyl resin (Mirex @ L-225 manufactured by Mitsui Toatsu Co., Ltd.) is reacted with allyl chloride or allyl bromide to obtain an allylic compound. II], in which a portion having each structural unit in the resin exists as a whole in the ratio of a, b, c, d.

(R ₃ , R ₄ : -H or a methyl group 0 <a, b, c, d <100 and a + b + c + d = 100 a, b, c, d indicate the percentage (%) of each structural unit) 10 ≦ a ≦ 70, 10 ≦ b ≦ 40 and 10 ≦ d ≦ 70 are good.

The component a is effective for improving the strength at heat and reducing the water absorption, but hardly reacts in the resin-forming reaction with the polymaleimide. The sex worsens.

The component b is an important component that reacts with a maleimide group in a resin-forming reaction with the polymaleimide to improve the compatibility between the polymaleimide and the polysiloxane. However, if too much, the phenolic hydroxyl group in the cured product increases,
The water absorption is increased, which is not preferable.

The d component has a significant effect of lowering the water absorption and improving the reliability. However, when the amount is too large, the reactivity in the resin generation reaction and the curing reaction deteriorates, and the resin is not suitable for a sealing material.

The ratio of allyl group / hydrosilyl group (Si-H) in the reaction between dihydropolysiloxane and allylated phenol / aromatic hydrocarbon resin is preferably 2/1 to 10/1. If there are too few allyl groups, compatibility with polymaleimide, moldability,
The mechanical strength of the cured product deteriorates. If it is too large, on the contrary, the amount of polysiloxane is reduced, so that the low stress characteristics are not improved.

The reaction conditions are not particularly limited, but as an example, in the presence of chloroplatinic acid, the reaction is carried out at 90 ° C. to reflux temperature in a toluene solvent. After the reaction, chloroplatinic acid is extracted and washed with water / toluene. After removal, the toluene is distilled off to obtain an allylated polysiloxane. The reaction is carried out using a hydrosilyl group (Si-
The reaction is preferably performed until the reaction rate of H) becomes 80% or more. If the reaction rate is less than 80%, the free polysiloxane component oozes out into the molded product, deteriorating the appearance and causing mold fogging.

The reaction between the polymaleimide and the allylated polysiloxane is not particularly limited to the reaction conditions, but as an example, the allylated polysiloxane is heated to 130 to 150 ° C.,
This is carried out by adding a polymaleimide. The amount of the allylated polysiloxane is 30 parts per 100 parts by weight of the polymaleimide.
~ 300 parts by weight is good. If the amount is too small, low stress characteristics cannot be obtained. If too large, the mechanical strength and Tg decrease, and cracks occur during solder immersion. The reaction is terminated until the obtained resin has a melting point in the range of 50 to 120 ° C. In order to confirm the end point of the reaction, a small amount of the resin is taken out of the reaction system, cooled, and the melting point is measured and confirmed.

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

As a general method of producing the resin composition for semiconductor encapsulation of the present invention as a molding material, a composition obtained by adding various additives to these essential components and uniformly mixing them is kneaded by a kneader, a hot roll, or the like. Then, after cooling, it is pulverized into a molding material.

If the obtained molding material is used for sealing semiconductors,
It is possible to obtain a highly reliable resin composition for semiconductor encapsulation which is Tg and has excellent low stress characteristics.

(Example) [Synthesis of Allylated Phenol / Aromatic Hydrocarbon Resin] Synthesis Example 1 Potassium hydroxide was added to a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel according to the recipe in Table 1. , A mixed solvent of water / acetone (1/1) was added and dissolved, and a phenol-modified xylene resin was added and dissolved therein.

The solution is heated, allyl bromide is added and refluxed for 3 hours.
Allowed to react for hours. Thereafter, the mixture was neutralized with hydrochloric acid to distill off unreacted allyl bromide with acetone, and 1 liter of toluene was added. It was transferred to a separating funnel, washed three times with water, and the solvent was removed with an evaporator.

Further, heat treatment was performed at 175 ° C. for 4 hours to obtain an allylated phenol aromatic hydrocarbon resin. The composition of the product is first
It is shown in the table.

Reference Example 1 A phenol-modified xylene resin of Synthesis Example 1 was replaced with a phenol resin and reacted similarly.

Examples 1-2 In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, the allylated phenol / aromatic hydrocarbon resin of Synthesis Example 1 and toluene were charged according to the formulation in Table 2 and uniformly dissolved. Was added to a solution of chloroplatinic acid in isopropanol. Dihydropolysiloxane was added thereto and reacted at 90 ° C. for 2 hours. After the reaction, the mixture was transferred to a separating funnel, washed three times with water, and the solvent was removed with an evaporator to obtain an allylated polysiloxane. The reaction rates of all hydrosilyl groups are
80% or more.

Next, the obtained allylated polysiloxane was placed in a reaction vessel equipped with a stirrer, a vacuum distillation apparatus, and a thermometer according to the recipe in Table 3, heated to 130 ° C, and then polymaleimide was added. (About 20 mmHg). The obtained silicone-modified maleimide resin was homogeneous and the melting points are shown in Table 3.

Comparative Example 1 The 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. As shown in Table 3, the obtained silicone-modified maleimide resin had a heterogeneous and oily silicone component oozing out.

Comparative Example 2 The same reaction was carried out using dihydropolysiloxane having a large degree of polymerization (n). The compatibility was very poor, and the obtained silicone-modified maleimide resin was heterogeneous, and the oily silicone component also bleed out.

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

Examples 3 to 4 According to the composition shown in Table 4, to the silicone-modified maleimide resin obtained in Examples 1 and 2, silica powder, a curing accelerator, an aminosilane, a colorant and a release agent were added, and kneaded with a hot roll. Thus, a molding material was obtained. The resulting molding material was molded by transfer molding at 180 ° C. for 3 minutes to obtain a glossy molded product without blisters. 180 more
After curing for 8 hours at ℃, 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 lower flexural modulus at room temperature, lower stress and lower internal stress than Comparative Example 8 containing no silicone. Moreover, the glass transition temperature is high, the bending strength at 260 ° C. is large, the heat resistance, the solder crack resistance is excellent, and the water absorption is small.

Comparative Examples 5 to 8 For comparison with Examples 3 and 4, molding materials were prepared and molded in the same manner as shown in Table 4.

Comparative Example 5 uses the resin of Comparative Example 1 (allyl group / hydrosilyl group = 1/1), but has poor moldability and poor appearance of the molded product due to mold clouding and low bending strength. .

Comparative Example 6 is a phenol resin containing no aromatic hydrocarbon of Reference Example 1. The material has a high bending strength and a high glass transition temperature, but has a large water absorption, so that the solder crack resistance is not sufficient.

Comparative Example 7 has substantially the same composition as Example 3, but is simply mixed at the time of compounding. As in Comparative Example 5, the appearance of the molded product was poor and the bending strength was low.

Comparative Example 8 does not contain polysiloxane.
Although the appearance, bending strength, and glass transition temperature of the molded product are as good as Comparative Example 6, the solder crack resistance is not sufficient because the bending elastic modulus and water absorption are large.

(Effect of the Invention) A molded article using the resin for semiconductor encapsulation according to the production method of the present invention has a high Tg, and has excellent moisture resistance and strength when heated, so that the solder crack resistance of the sealed body is good, In addition, it has low stress and excellent heat cycle resistance, and is a highly reliable and excellent resin composition for semiconductor encapsulation.

Continued on the front page (51) Int.Cl. ⁶ identification code FI H01L 23/31 (58) Fields investigated (Int.Cl. ⁶ , DB name) C08L 61/00-61/18 C08L 65/00-65 / 04 C08L 83/00-83/16 H01L 21 / 56,23 / 30

Claims (1)

(57) [Claims] (1) 100 parts by weight of a polymaleimide; (B) a dihydropolysiloxane represented by the following formula [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 following formula [II] (R ₃ , R ₄ : -H or methyl group 0 <a, b, c, d <100 and a + b + c + d = 100 10 ≦ a ≦ 70, 10 ≦ b ≦ 40, 10 ≦ d ≦ 70 a, b, c, d indicates the percentage of each structural unit.) The ratio of allyl group / hydrosilyl group (Si-H) is 2/1 to 10/1.
Wherein 30 to 300 parts by weight of an allylated polysiloxane obtained by reacting until the conversion of the hydrosilyl group becomes 80% or more is reacted until the melting point of the produced resin becomes 50 to 120 ° C. A method for producing a resin for semiconductor encapsulation.