JPS62240315A - Resin composition for sealing use - Google Patents

Abstract

PURPOSE:To obtain the titled composition with little stress development, outstanding in moisture and soldering heat resistance, by blending an epoxy resin, novolak type phenolic resin, water-crosslinkable rubber elastomer of specific formula and inorganic filter in specified production. CONSTITUTION:The objective composition can be obtained by blending (A) an epoxy resin, (B) a novolak type phenolic resin, (C) a water-crosslinkable rubber elastomer having active silane group, of formula Si(R<1>)n(OR<2>)3-n (R<1> is alkyl; R<2> is alkyl or phenyl; n is 0-2), and (D) inorganic filler. The amounts of the above components to be incorporated are such that: (1) the component C... 0.1-30wt% based on the final composition (2) the component D... 25-90wt% based on the final composition (3) The equivalent ratio of a for the epoxy group in the component A to b for the phenolic hydroxyl group in the component B... pref. 0.1-10. USE:Electrical and electronic parts.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides an electronic and
The present invention relates to a resin composition for sealing electrical parts.

(Conventional technology) Conventional diode, transistor,! ! 2. Description of the Related Art Methods of sealing electronic components such as integrated circuits using thermosetting resin have been used. This resin sealing is widely put into practical use because it is economically advantageous compared to hermetic sealing methods using glass, metal, or ceramic. Among thermosetting resins used as sealing resins, epoxy resins are most commonly used. Epoxy resin is 1llI anhydride,
Hardening agents such as aromatic amines and novolac type phenolic resins are used. Among these, epoxy resins using novolac type phenolic resin as a curing agent have excellent moldability and moisture resistance, are non-toxic, and are inexpensive compared to those using other curing agents, so they are used as semiconductor encapsulation materials. Widely used.

(Problem to be solved by the invention) However, in recent years, in the field of semiconductor integrated circuits, elements have become more highly integrated and pellets have become larger. However, this method had the disadvantage that it contracts during molding and hardening, applying stress to the semiconductor element, resulting in poor reliability. When a molded product (sealed product) using such resin is subjected to a 4-cold cycle test, open bonding wires, resin cracks, and pellet cracks occur, making it impossible to function as an electronic component. .

Furthermore, automation of semiconductor device assembly processes is currently being promoted. For example, when attaching a flat package type semiconductor device to a circuit board, conventionally soldering was done for each lead bin, but recently the entire semiconductor device has been soldered at 250°C.
A method has been adopted in which soldering is performed by immersing the device in a solder bath heated to the above temperature.

When the entire molded article using conventional epoxy resin is immersed in a solder bath, there is a drawback that peeling occurs between the resin and the semiconductor pellet and frame, resulting in significant deterioration of moisture resistance.

The present invention was made to eliminate these drawbacks, and an object of the present invention is to provide a sealing resin composition that is low in stress and has excellent moisture resistance, soldering heat resistance, and crack resistance.

[Structure of the Invention] (Means and Effects for Solving the Problem) As a result of intensive research aimed at achieving the above object, the present inventors have developed a three-dimensional epoxy resin using a novolak type phenolic resin as a curing agent. The present invention was completed by discovering that by introducing a separate network structure using a water-crosslinkable rubber elastomer into the structure, which is not mutually involved, low stress and excellent moisture resistance, soldering heat resistance, and crack resistance can be achieved. It was then.

That is, the present invention provides the following: (A) Epoxy resin (B) Novolac type phenolic resin (C) General formula % formula % (2) (However, R1 is an alkyl group, R2 is an alkyl group or a phenyl group, and n is O The water-crosslinkable rubber elastomer having an active silane group (representing an integer of 2 to 2) and (D) an inorganic filler are essential components, and the water-crosslinkable rubber elastomer I. This is a resin composition for sealing, characterized in that it contains 0.1 to 30 wt. %5 of the inorganic filler (D) and 25 to 90 wt. Then, sealing in which the equivalent ratio [(a)/(b)] between the epoxy group (a) of the epoxy resin and the phenolic hydroxyl W (b) of the novolac type phenolic resin is within the range of 0.1 to 10. It is a resin composition for

The epoxy resin (A) used in the present invention is not particularly limited in terms of its molecular structure and molecule m, 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.

(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 may be used alone or in combination of two or more. It will be done.

The (B) novolak type phenolic resin used in the present invention includes novolak type phenol resins obtained by reacting phenols such as phenol and alkyl phenols with formaldehyde or paraformaldehyde, and modified resins thereof, such as epoxidized or butylated resins. Examples include novolac type phenolic resins. The blending ratio of the novolac type phenolic resin is determined by the ratio of the epoxy m<a> of the (Δ) epoxy resin and ([3) the phenolic water M base of the novolac type phenolic resin (b) [
(a)/(b)] is preferably within the range of 0.1 to 10. If this equivalent ratio is less than 0.1 or more than 10, the moisture resistance, molding workability, and electrical properties of the cured product will deteriorate, which is undesirable in either case. Therefore, it is limited within the above range.

(C) Water-crosslinkable rubber elastomer having an active silane group represented by the general formula % (2) used in the present invention 1
-mer (in the formula, R1 represents an alkyl group, R2 represents an alkyl group or a phenyl group, and n represents an integer of 0 to 2) is an active silane group of -8i<R') (OR'
) There are no particular restrictions on the molecular structure, molecular weight, etc., as long as it has n 3-n . Specifically, there are the following:

(However, m represents an integer of 1 or more.) A molded product of a sealing resin composition using a water-crosslinkable rubber elastomer having an active silane group was subjected to a pressure hookah test (PCT) for evaluation of air or moisture resistance. ) When placed in the device, no crosslinking reaction occurs due to moisture in the cylinder. That is,
When molded with a sealing resin composition using a water-crosslinkable rubber elastomer having active silane groups, as a first crosslinking reaction after molding, the epoxy resin of the sealing resin composition is cured using a novolac type phenolic resin as a curing agent. This creates a three-dimensional structure of epoxy resin. Next, as a second crosslinking reaction, another network structure of the rubber elastomer I/mer is completed, and each three-dimensional structure does not interact with each other, resulting in a so-called mutual network structure. Therefore, the blending of the water-crosslinkable rubber elastomer has the effect of imparting flexibility to the resin composition, relaxing stress, resulting in low stress, and less deterioration of moisture resistance even when immersed in a solder bath. The blending ratio of this water-crosslinkable rubber elastomer to the resin composition is 0.1 to 30! ! ! amount%
It is desirable to do so. If the proportion is less than 0.1@l1%, it has no effect on low stress, 4-cold cycle, and soldering heat resistance, and if it exceeds 30m ffi%, moldability deteriorates, making it unsuitable for practical use.

Examples of the inorganic filler (D) used in the present invention include silica powder, alumina, antimony trioxide, talc, calcium carbonate, titanium white, clay, mica, red iron, glass fiber, carbon fiber, etc. Among these, silica Powder and alumina are preferably used. The blending ratio of the inorganic filler is preferably 25 to 90% by weight based on the resin composition. When the proportion is less than 25% by weight, there is no effect on moisture resistance, heat resistance, mechanical properties and moldability, and when it exceeds 90% by weight, the bulk becomes large and the moldability is poor, making it unsuitable for practical use.

The sealing resin composition of the present invention contains an epoxy resin, a novolac type phenol resin, a water-crosslinkable rubber elastomer having an active silane group, and an inorganic filler as essential components.
If necessary, for example, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, mold release agents such as paraffins, chlorinated paraffins, bromotoluene, hexabromobenzene, antimony trioxide, etc. Flame retardants, colorants such as carbon black and red iron oxide, silane coupling agents, various curing accelerators, etc. can also be appropriately added and blended.

General method 4 for producing the encapsulating resin composition of the present invention as a molding material involves adding an epoxy resin, a novolac type phenol resin, a water-crosslinkable rubber elastomer having an active silane group, an inorganic filler, etc. After mixing the raw material compositions selected to have the composition ratio sufficiently uniformly using a mixer, etc., the mixture is further melted and mixed using hot rolls, or mixed using a kneader, etc., and then cooled to solidify and pulverized to an appropriate size. and use it as a molding material. In producing the molding material, a water-crosslinkable rubber elastomer having active silane groups is used, so the environment during the production process must be carefully monitored. That is, the water-crosslinkable rubber elastomer is
Since crosslinking occurs due to moisture in the air, it is important to sufficiently control the environmental humidity from the raw material stage and to manufacture under as low humidity conditions as possible. The molding material thus obtained can be applied to sealing, covering, insulating, etc. electronic or electrical components.

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

Example 1 Cresol novolac epoxy resin (epoxy 5/21
5) 18%, 9% novolac type phenolic resin (phenol weight 1107), 3% water-crosslinkable rubber elastomer, 69% fused silica powder, 0.3% curing accelerator, 0.3% ester wax, and silane. 0.4% of a coupling agent was mixed at room temperature, further kneaded at 90 to 95°C, cooled, and then crushed to obtain a molding material.

The obtained molding material was transfer-injected into a mold heated to 170° C. and cured to obtain a molded product (sealed product).
This molded article was tested for various properties related to moisture resistance, stress, etc., and the results are shown in Table 1. Remarkable effects of the present invention were observed.

Example 2 Cresol novolak epoxy resin (epoxy υ21
5) 18%, novolak type phenolic resin (phenol fi 107) 9%, water-crosslinkable rubber elastomer 3%, silica powder 69%, curing accelerator 0.3%, ester wax 0.3%, and silane type 0.4% of the coupling agent was mixed, mixed, and crushed in the same manner as in Example 1 to obtain a molding material. Molded articles were also obtained in the same manner, and these molded articles were tested for various properties related to moisture resistance, stress, etc. in the same manner as in Example 1. The results are shown in Table 1. Remarkable effects of the present invention were observed.

Comparative Example Cresol novolak epoxy resin (epoxy 121
5) To 20%, add 10% novolac type phenolic resin (phenol weight 1107), 69% silica powder, 0.3% curing accelerator, 0.3% ester wax, and 0.4% silane coupling agent. Mix as in the example,
The mixture was mixed and crushed to obtain a molding material.

This molding material was used to make a molded article, and the various properties of the molded article were tested in the same manner as in the examples. The results are shown in Table 1.

Table 1 1:1 Nikrac number is 30×25×5fflIm
A 25 x 25 x 1 copper plate is embedded in the bottom of the molded product,
Place it in a constant temperature bath at -40℃ and +200℃ for 30 minutes each.
Resin cracks after 15 cycles were investigated.

The time at which this occurred was evaluated.

*3: Using a sealing resin composition (molding material),
Regular 427 electrical components with aluminum wiring
It was adhered to a zero frame and transfer molded for 3 minutes at 170°C to obtain a flat package molded product measuring 5 x 10 x 1.5 mm, which was then post-cured at 180°C for 8 hours. This molded product was heated to 40℃ in advance, 90% RI-1゜1.
After 00 hours of moisture absorption treatment, it was placed in a solder bath at 250℃ for 10 hours.
Immersed for seconds. After that, a pressure tester test (PCT) was performed in saturated steam at 127°C and 2.5 atm.
Disconnection due to aluminum corrosion was evaluated as a defect.

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

[Effects of the Invention] As is clear from the above explanation and Table 1, the encapsulating resin composition of the present invention has low stress and excellent moisture resistance, soldering heat resistance, and heat resistance, so it is suitable for bonding wires. There are no opens, resin cracks, or pellet cracks, and the stress caused by shrinkage during curing is low, and it shows excellent characteristics even after being immersed in a solder bath at temperatures of 250°C or higher. You can get electrical parts.

Claims (1)

[Claims] 1 (A) Epoxy resin (B) Novolak phenolic resin (C) General formula -Si(R^1)_n(OR^2)_3_-_n (wherein R^1 represents an alkyl group) , R^2 represents an alkyl group or a phenyl group, and n represents an integer of 0 to 2. A sealing resin characterized by containing the water-crosslinkable rubber elastomer (C) in an amount of 0.1 to 30% by weight and the inorganic filler (D) in an amount of 25 to 90% by weight. Composition. 2 Equivalence ratio of the epoxy group (a) of the epoxy resin and the phenolic hydroxyl group (b) of the novolac type phenolic resin [
(a)/(b)] is within the range of 0.1 to 10.