JPH04258626A - Sealing resin composition and sealed semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a sealing resin composition having good moldability and excellent humidity resistance and soldering-heat resistance by mixing an o-cresol novolac epoxy resin with a polyphenolic resin, a specified amount of a specified phosphine compound and a silica powder. CONSTITUTION:A sealing resin composition is obtained by mixing an o-cresol novolac epoxy resin (A) with a polyphenolic resin (B) of formula I or II (wherein (n) is 0 or an integer of 1 or greater) R is CmH2m+1; and (m) is 0 or an integer of 1 or greater), a tris(o,p-substituted phenyl)phosphine (C) of formula III (wherein R<1>, R<2> and R<3> are each an electron-donating group or H, and at least one of them is an electron-donating group) and a silica powder (D) as essential components, wherein component C is used in an amount of 0.01-5wt.% based on the resin composition. This composition has excellent moldability, is lowly affected by absorbed humidity and excels in humidity resistance and soldering- heat resistance after immersion in solder or reflow of solder after sealing.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for sealing which has good moldability and excellent moisture resistance and soldering heat resistance, and a semiconductor sealing device sealed with the composition.

0002

2. Description of the Related Art In recent years, the practical use of thin packages has been promoted for semiconductor devices. For example, flat packages in integrated circuits, SOP (smalloutl...
ine package), TSOP(thins
0.1 to 0.5 mm on the top surface of the semiconductor element or the back surface of the isolation type package, etc.
It is now necessary to fill the thin parts with resin. On the other hand, surface-mount packages use a solder dipping method or a solder reflow method when attaching them to a circuit board, creating an even harsher environment for the sealing resin that makes up the package.

Conventional sealing resins are composed of novolac type epoxy resin, novolac type phenol resin, silica powder, and a known curing accelerator, but when sealed with this sealing resin, the resin is deposited in thin parts. It has disadvantages such as poor moldability such as not being filled, causing cavities and blisters, and a decrease in moisture resistance and poor appearance. Further, the semiconductor device sealed with the conventional sealing resin described above has a drawback in that moisture resistance decreases when the entire device is immersed in a solder bath or the like. In particular, if a semiconductor device that has absorbed moisture is immersed in a solder bath, peeling may occur between the encapsulating resin and the semiconductor element, between the encapsulating resin and the lead frame, or internal resin cracks may occur, resulting in significant deterioration of moisture resistance and corrosion of the electrodes. This causes wire breakage and leakage current due to moisture. As a result, the semiconductor device has the disadvantage that long-term reliability cannot be guaranteed.

0004

[Problems to be Solved by the Invention] The present invention has been made in order to eliminate the above-mentioned drawbacks. The object of the present invention is to provide a sealing resin composition and a semiconductor sealing device that have excellent moisture resistance and soldering heat resistance and can guarantee long-term reliability.

[0005]

[Means for Solving the Problems] As a result of intensive research aimed at achieving the above object, the present inventors have found that by using a composition as described below, the moldability of thin-walled parts, moisture resistance, and solderability can be improved. The present invention was completed by discovering that a sealing resin composition and a semiconductor sealing device with excellent heat resistance can be obtained.

That is, the present invention provides (A) an o-cresol novolac type epoxy resin, (B) the following general formula (I).
or a polyfunctional phenolic resin represented by (II)

00
07]

[Formula 5] (where n is an integer of 0 or 1 or more, R is Cm
H2m+1, where m represents an integer of 0 or 1 or more)
, (C) tris(ortho-para substituted phenyl)phosphine represented by the following general formula

[0008]

[Chemical formula 6] (However, in the formula, R1, R2, R3 represent an electron donating group or a hydrogen atom, and at least one of R1, R2, R3 is an electron donating group), and (D) silica powder is essential. component, and the above (C) for the resin composition.
tris(ortho-para substituted phenyl)phosphine
This is a sealing resin composition characterized in that it contains 0.01 to 5% by weight. Further, the present invention is a semiconductor sealing device characterized in that a semiconductor device is sealed with a cured product of this sealing resin composition.

The present invention will be explained in detail below.

The o-cresol novolac type epoxy resin (A) used in the present invention has the following formula:

[0011]

embedded image (wherein n represents a positive integer) is used, and there are no particular restrictions on molecular weight or the like. A novolac type epoxy resin or an epichlorohydrin bisphenol type epoxy resin can also be used in combination with this epoxy resin.

The polyfunctional phenolic resin (B) used in the present invention is a trifunctional, tetrafunctional or higher functional phenolic resin as shown in formula (I) or (II) above, and has the above-mentioned skeleton structure in its molecule. As long as it has, there are no particular restrictions on other molecular structures, molecular weights, etc., and it can be widely used. Specific examples of the polyfunctional phenolic resin (B) include trifunctional and tetrafunctional phenolic resins as shown in the following formula.

[0013]

[Chemical formula 8]

[0014]

[Image Omitted] [Image Omitted] These may be used alone or in combination of two or more. Furthermore, in addition to polyfunctional phenol resins, novolac type phenol resins obtained by reacting phenols such as phenol and alkylphenols with formaldehyde or paraformaldehyde, and modified resins thereof can be used in combination.

Tris(ortho/para substituted phenyl)phosphine (C) used in the present invention has the above general formula, and has an electron donating group substituted at the ortho/para position of the phenyl group in triphenylphosphine. However, it does not necessarily have to be all replaced. That is,
Only one ortho position, ortho and para positions, ortho and ortho positions, only para position, two ortho and para positions. Examples of the electron donating group include an alkoxy group, an amino group, a hydroxyl group, a halogen group, and an alkyl group. Tris (ortho-para substituted phenyl)
Phosphine is used as a curing accelerator. In addition to this tris(ortho-para substituted phenyl)phosphine, known curing accelerators such as imidazole accelerators, diazabicycloundecene (DBU) accelerators, phosphorus accelerators, and other accelerators may be used in combination. be able to.

(C) The blending ratio of tris(ortho-para substituted phenyl)phosphine is 0.00% relative to the resin composition.
It is desirable to contain 01 to 5% by weight. If the proportion is less than 0.01% by weight, the gel time of the resin composition is long and the curing properties are also poor, which is not preferable. If it exceeds 5% by weight, fluidity becomes extremely poor and moldability becomes poor.
Moreover, the electrical properties are also deteriorated, and the moisture resistance is also inferior, which is not preferable.

As the silica powder (D) used in the present invention, commonly used silica powders are widely used, but among them, silica powders with a low impurity concentration and an average particle size of 30 μm are used.
The following are desirable. If the average particle size exceeds 30 μm, moisture resistance and moldability will be poor, which is not preferable.

The sealing resin composition of the present invention contains an o-cresol novolac type epoxy resin, a polyfunctional phenol resin, a tris (ortho/para substituted phenyl) phosphine curing accelerator, and silica powder as essential components. To the extent that it does not contradict the purpose of the invention, and as necessary, use of difficult substances such as natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, release agents for paraffins, antimony trioxide, etc. A repellent, a coloring agent such as carbon black, a silane coupling agent, a curing accelerator, a rubber-based or silicone-based low stress imparting agent, etc. can be appropriately added and blended.

The general method for preparing the encapsulating resin composition of the present invention as a molding material is to prepare the above-mentioned components, namely, o-cresol novolak type epoxy resin, polyfunctional phenolic resin, tris (ortho-para. A curing accelerator for substituted phenyl)phosphine, silica powder, and others are blended and mixed thoroughly and uniformly using a mixer or the like. Further, the mixture can be melted and mixed using hot rolls or mixed using a kneader, etc., and then cooled and solidified to be crushed into a suitable size to obtain a molding material. This molding material can be applied to seal electronic or electrical parts, as well as for coating, insulation, etc., and can provide excellent properties and reliability.

The semiconductor encapsulation device of the present invention can be manufactured by encapsulating a semiconductor device using the above-mentioned encapsulation resin composition. Semiconductor devices to be sealed include, for example, integrated circuits, large-scale integrated circuits, transistors,
It is not particularly limited to thyristors, diodes, etc., and can be widely used. The most common method of sealing is
There is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting, etc. is also possible. The encapsulating resin composition is cured by heating after encapsulation molding, and a semiconductor device encapsulated by the cured product of this composition is finally obtained. Curing by heating is preferably performed at a temperature of 150° C. or higher.

[0021]

[Operation] The encapsulating resin composition and semiconductor encapsulating device of the present invention can be reacted using an o-cresol novolac type epoxy resin, a polyfunctional phenol resin, and a tris (ortho-para substituted phenyl) phosphine curing accelerator. The purpose was achieved by That is, Tris (ortho)
By blending a predetermined amount of a para-substituted phenyl (phosphine) curing accelerator and controlling the gelation time and fluidity of the resin composition, filling properties in thin-walled areas were improved, moisture resistance was improved, and excellent moldability was imparted. Furthermore, by reacting the o-cresol novolak type epoxy resin with the polyfunctional phenol resin, the glass transition temperature is raised, the properties at heat are improved, and the hygroscopicity of the resin composition is reduced. As a result, even if solder immersion or solder reflow is performed, resin cracks will not occur, and in particular, moisture resistance will not deteriorate.

[0022]

EXAMPLES Next, examples of the present invention will be described, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, "%" means "% by weight".

Example 1 17% o-cresol novolak type epoxy resin, 8% trifunctional phenol resin of formula 8, tris(2,6-
Diethoxyphenyl)phosphine curing accelerator 0.3
%, 74% silica powder, 0.3% ester wax and 0.4% silane coupling agent were mixed at room temperature,
The mixture was further kneaded at a temperature of 90 to 95°C, cooled, and then crushed to produce a molding material (A).

Example 2 12% o-cresol novolak type epoxy resin, 6% trifunctional phenol resin of formula 8, tris(2,6-
Diethoxyphenyl)phosphine curing accelerator 0.3
%, 81% silica powder, 0.3% ester wax and 0.4% silane coupling agent at room temperature,
The mixture was further kneaded at a temperature of 90 to 95°C, cooled, and then ground to produce a molding material (B).

Comparative Example 1 17% o-cresol novolac type epoxy resin, 8% novolac type phenol resin, 74% silica powder, imidazole curing accelerator 0.3%, ester wax 0.3% and silane coupling agent 0 A molding material (C) was produced in the same manner as in Example 1 except that .4% was added.

Comparative Example 2 12% o-cresol novolac type epoxy resin, 6% novolac type phenol resin, 81% silica powder, imidazole curing accelerator 0.3%, ester wax 0.3% and silane coupling agent 0 A molding material (D) was produced in the same manner as in Comparative Example 1 except that .4% was added.

The molding materials (A) to (D) manufactured in Examples 1 to 2 and Comparative Examples 1 to 2 and the semiconductor encapsulation device manufactured using these were tested for moldability and moisture resistance, and the results are as follows. are shown in Table 1. The present invention was excellent in all cases, and the remarkable effects of the present invention could be confirmed.

[0028]

[Table 1] *1: Using the molding material in a mold at 175℃ 10
The spiral flow distance was measured by applying a pressure of 0 kg/cm2 *2: The time until the molding material gelled on a hot plate at 175°C was measured *3: Using the molding material, in a mold at 175°C 100
Applying a pressure of kg/cm2, 200μm, 30
The flow distance through gaps of 0 μm and 10 μm was measured *4: Using a molding material, QFP (14×14×1.
A dummy chip of 8 x 8 mm was placed in a 4 mm) package, and the number of filling defects on the top surface of the chip among 500 packages was measured.
Place the dummy chip in a 20-inch package and package it.
The number of filling defects on the back side was measured out of 500 pieces. *6: Using molding material, DIP-16 pin MOSI
For each of the semiconductor sealing devices that sealed the C test element or the TO-220 type test element, the time until the open failure of the aluminum wiring reached 50% was measured under the condition of PCT 4 atmospheres.

[0029]

Effects of the Invention As is clear from the above explanation and Table 1, the encapsulating resin composition of the present invention has excellent moldability, is less affected by moisture absorption, and has excellent moisture resistance after immersion in a solder bath and soldering heat resistance. Because of its excellent performance, it can be easily filled into thin-walled areas without forming cavities or blisters, preventing peeling between the resin composition and the semiconductor device or between the resin composition and the lead frame, and preventing internal resin cracks from occurring, as well as preventing electrode corrosion. An excellent and highly reliable semiconductor encapsulation device was obtained, which did not cause wire breakage due to oxidation or leakage current due to moisture.

Claims (2)

[Claims] Claim 1: (A) an o-cresol novolac type epoxy resin, (B) a polyfunctional phenolic resin represented by the following general formula (I) or (II): (where n is 0 or An integer of 1 or more, R is Cm
H2m+1, where m represents an integer of 0 or 1 or more)
, (C) Tris(ortho/para-substituted phenyl)phosphine represented by the following general formula [Chemical formula 2] (However, in the formula, R1, R2, R3 represent an electron donating group or a hydrogen atom, (at least one of which is an electron donating group) and (D) silica powder are essential components, and the above (C) is added to the resin composition.
tris(ortho-para substituted phenyl)phosphine
A sealing resin composition characterized in that it contains 0.01 to 5% by weight. Claim 2: (A) an o-cresol novolac type epoxy resin, (B) a polyfunctional phenolic resin represented by the following general formula (I) or (II): (wherein n is 0 or an integer greater than or equal to 1, R is C
m H2m+1, m represents an integer of 0 or 1 or more), (C) tris(ortho/para-substituted phenyl)phosphine represented by the following general formula [Chemical formula 4] (However, in the formula, R1, R2, R3 are represents an electron donating group or a hydrogen atom, and at least one of R1, R2, and R3 is an electron donating group), and (D) silica powder are essential components, and the above (C) is added to the resin composition.
tris(ortho-para substituted phenyl)phosphine
A semiconductor encapsulation device characterized in that a semiconductor device is encapsulated with a cured product of a encapsulation resin composition containing 0.01 to 5% by weight.