JPH04258624A - 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 a specified alkyl-modified polyepoxy resin with a polyphenolic resin, a specified amount of a specified phosphine compound and a silica powder. CONSTITUTION:The title composition is obtained by mixing (A) an alkyl- modified polyepoxy resin prepared by epoxidizing the phenolic hydroxyl groups of a resin obtained by reacting an alkyl-substituted hydroxybenzaldehyde, derived by substituting the ring hydrogen atoms of hydroxybenzaldehyde with alkyl groups, with an alkyl-substituted phenol, derived by substituting the ring hydrogen atoms of phenol with alkyl groups with (B) a polyphenolic resin 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), (C) a tris(o,p-substituted phenyl) phosphine of formula III (wherein R<1> to R<3> are each an electron-donating group or H, and at least one of them is an electron-donating group) and (D) a silica powder, wherein component C is used in an amount of 0.01-5wt.%.

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, when a semiconductor device that has absorbed moisture is immersed in a solder bath, peeling occurs between the encapsulating resin and the semiconductor element, between the encapsulating resin and the lead frame, and internal resin cracks occur, resulting in significant deterioration of moisture resistance and the electrodes. Wire breakage occurs due to corrosion and leakage current occurs 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 involves reacting (A) an alkyl-substituted hydroxybenzaldehyde in which the aromatic ring hydrogen of hydroxybenzaldehyde is substituted with an alkyl group and an alkyl-substituted phenol in which the aromatic ring hydrogen of phenol is substituted with an alkyl group. an alkyl-modified polyfunctional epoxy resin obtained by epoxidizing the phenolic hydroxyl groups in the resin obtained by C
n H2n+1, an integer of 10≧n≧1), (B
) A polyfunctional phenolic resin represented by the following general formula (I) or (II)

[0007]

[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]

embedded image (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. The above (C
This is a sealing resin composition characterized by containing 0.01 to 5% by weight of tris(ortho-para substituted phenyl)phosphine. 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 alkyl-modified polyfunctional epoxy resin (A) used in the present invention has a phenol resin skeleton structure obtained by reacting an alkyl-substituted hydroxybenzaldehyde and an alkyl-substituted phenol, and the phenol in the resin skeleton structure As long as the molecule has the same skeletal structure, the molecular structure is epoxidized.
There are no particular restrictions on molecular weight, etc., and a wide range of uses can be made.

As the alkyl-modified polyfunctional epoxy resin (A), those having the following structural formula can be exemplified.

0012

[Formula 7] (wherein, R3 is an integer of Cm H2m+1, m≧1, and R4 is Cn H2n+1, 10≧n≧1
In addition, (A) the alkyl-modified polyfunctional epoxy resin may be used in combination with a novolac-type epoxy resin or an epibis-type epoxy resin, if necessary. These alkyl-modified polyfunctional epoxy resins may be used alone or in combination with two
More than one species can be used.

The polyfunctional phenolic resin (B) used in the present invention is a trifunctional, tetrafunctional or higher functional phenolic resin as shown in the above formulas (I) and (II), and has the above-mentioned skeleton structure in its molecule. Other molecular structures, as long as they have
There are no particular restrictions on molecular weight, etc., and a wide range of uses can be made. Specific examples of the polyfunctional phenolic resin (B) include trifunctional and tetrafunctional phenolic resins as shown in the following formula.

[0014]

[Chemical formula 8]

[0015]

[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 is a triphenylphosphine substituted with an electron donating group at the ortho/para position of the phenyl group. 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 alkyl-modified polyfunctional epoxy resin, a polyfunctional phenol resin, a tris (ortho- and para-substituted phenyl) phosphine curing accelerator, and silica powder as essential components. Within the limits that do not contradict the purpose of the product, and as necessary, flame retardants such as natural waxes, synthetic waxes, metal salts of straight-chain fatty acids, acid amides, esters, release agents for paraffins, antimony trioxide, etc. , 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.

[0020] A general method for preparing the sealing resin composition of the present invention as a molding material is based on the above-mentioned components, namely, an alkyl-modified polyfunctional epoxy resin, a polyfunctional phenol resin, and a tris (ortho- and para-substituted) resin composition. Phenyl) phosphine curing accelerator, silica powder, and others are blended and mixed thoroughly and uniformly using a mixer or the like. Furthermore, a melt mixing process using a hot roll or a mixing process using a kneader etc. is performed,
It can then be cooled and solidified and pulverized into a suitable size to form 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.

[0022]

[Operation] The encapsulating resin composition and semiconductor encapsulating device of the present invention can be produced by reacting with an alkyl-modified polyfunctional epoxy resin, a polyfunctional phenol resin, and a tris (ortho- and para-substituted phenyl) phosphine curing accelerator. The purpose has been achieved. In other words, by incorporating a predetermined amount of tris (ortho-para substituted phenyl) phosphine curing accelerator and controlling the gelation time and fluidity of the resin composition, filling properties in thin-walled areas are improved, moisture resistance is improved, and excellent molding is achieved. gave gender. In addition, by reacting the alkyl-modified polyfunctional epoxy resin and the polyfunctional phenol resin, the glass transition temperature is raised, the properties under 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.

[0023]

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% alkyl-modified polyfunctional epoxy resin of chemical formula 7, 8% of trifunctional phenol resin of chemical formula 8, 0.3% of tris(2,6-diethoxyphenyl)phosphine curing accelerator, silica powder 74%, ester wax 0.3%, and silane coupling agent 0.4% were mixed at room temperature, further kneaded at a temperature of 90 to 95°C, cooled, and then crushed to produce a molding material (A).

Example 2 12% alkyl-modified polyfunctional epoxy resin of chemical formula 7, 6% of trifunctional phenol resin of chemical formula 8, 0.3% of tris(2,6-diethoxyphenyl)phosphine curing accelerator, silica powder 81%, ester wax 0.3%, and silane coupling agent 0.4% were mixed at room temperature, further kneaded at a temperature of 90 to 95°C, cooled, and crushed 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 hardening 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) produced in Examples 1 to 2 and Comparative Examples 1 to 2 and the semiconductor encapsulation device produced 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.

[0029]

[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, 3
The flow distance was measured through gaps of 00 μm and 10 μm *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 was measured among 500 packages.
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.

[0030]

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) Obtained by reacting an alkyl-substituted hydroxybenzaldehyde obtained by substituting the aromatic ring hydrogen of hydroxybenzaldehyde with an alkyl group and an alkyl-substituted phenol obtained by substituting the aromatic ring hydrogen of phenol with an alkyl group. Alkyl-modified polyfunctional epoxy resin in which the phenolic hydroxyl group in the resin is epoxidized (however,
The alkyl group of the alkyl-substituted hydroxybenzaldehydes is CmH2m+1, an integer of m≧1, and the alkyl group of the alkyl-substituted phenols is CnH2n+1,1
0≧n≧1 integer), (B) the following general formula (I)
or polyfunctional phenolic resin represented by (II) [Formula 1] (wherein, 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] (wherein, 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) Obtained by reacting an alkyl-substituted hydroxybenzaldehyde in which the aromatic ring hydrogen of hydroxybenzaldehyde is substituted with an alkyl group and an alkyl-substituted phenol in which the aromatic ring hydrogen of phenol is substituted with an alkyl group. Alkyl-modified polyfunctional epoxy resin in which the phenolic hydroxyl group in the resin is epoxidized (however,
The alkyl group of the alkyl-substituted hydroxybenzaldehydes is CmH2m+1, an integer of m≧1, and the alkyl group of the alkyl-substituted phenols is CnH2n+1,1
0≧n≧1 integer), (B) the following general formula (I)
or a polyfunctional phenolic resin represented by (II) [Formula 3] (wherein, n is an integer of 0 or 1 or more, and 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 4] (However, in the formula, R1, R2, and R3 represent an electron donating group or a hydrogen atom, and R1, R2, and R3 represent (at least one of which is an electron donating group) and (D) silica powder are essential components, and the above (C
) A semiconductor encapsulation characterized in that a semiconductor device is encapsulated with a cured product of a encapsulation resin composition containing 0.01 to 5% by weight of tris(ortho-para substituted phenyl)phosphine. Stop device.