JPH04248831A - Sealing resin composition and sealed semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a sealing resin composition, containing a specific epoxy resin, a polyfunctional phenolic resin, silica powder and a prescribed amount of a tris(ortho-para-substituted phenyl)phosphine as a curing accelerator and excellent in moldability. CONSTITUTION:A sealing resin composition excellent in moisture resistance and solder heat resistance after dipping in solders or solder reflow is obtained by including (A) an epoxy resin expressed by formula I [(n) is >=0], (B) a polyfunctional phenolic resin such as tri- or tetrafunctional phenolic resin expressed by formula II or III {R is CmH2m+1 [(m) is >=0], (C) a tris(ortho.parasubstituted phenyl)phosphine expressed by formula IV (R<1>, R<4> and R<3> are electron donative group such as alkoxy, ammno or alkyl or H) as a curing accelerator and (D) silica powder as a filler as essential components. The amount of the aforementioned component (C) is 0.01-5wt.% based on the resin composition.

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
(mall outline package), and isolation type packages for power transistors, etc., the thin part of about 0.1 to 0.5 mm, such as the top surface of the semiconductor element or the back surface of the insulation type package, must be filled with resin. It is no longer true. 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, peeling between the encapsulating resin and the semiconductor element, between the encapsulating resin and the lead frame, and internal resin cracks may occur, resulting in significant deterioration of moisture resistance, leading to wire breakage due to electrode corrosion. Water causes leakage current. the result,
Semiconductor devices have 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.

[0006] That is, the sealing resin composition of the present invention:
(A) Epoxy resin represented by the following formula

[0007]

[Chemical formula 7] (where n represents an integer of 0 or 1 or more), (
B) Polyfunctional phenolic resin represented by the following general formula (I) or (II)

[0008]

[Chemical formula 8] (In the formula, n is an integer of 0 or 1 or more, and R is Cm
H2m+1, m represents 0 or an integer greater than or equal to 1)
, (C) tris(ortho, para-substituted phenyl)phosphine represented by the following general formula

[0009]

embedded image (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. Tris(ortho, para-substituted phenyl)phosphine of the above (C) is added as an essential component to the resin composition by 0.0
It is characterized in that it is contained in a proportion of 1 to 5% by weight. Further, the semiconductor sealing device of the present invention is characterized in that a semiconductor device is sealed with a cured product of the above-mentioned sealing resin composition.

The present invention will be explained in detail below.

The epoxy resin (A) used in the present invention is represented by the following general formula.

0012

embedded image (where n is 0 or an integer of 1 or more) Epoxy resins represented by the above formula are not particularly limited by molecular weight, etc., and can be widely used. Further, a novolac type epoxy resin or an epibis type epoxy resin can be used in combination as required.

The polyfunctional phenol resin (B) used in the present invention is a trifunctional or higher functional phenol resin as shown by the above formula, and as long as it has the above skeleton structure in its molecule,
Other molecular structures, molecular weights, etc. are not particularly limited, and they can be widely used. Specific (B) polyfunctional phenolic resins include trifunctional and tetrafunctional phenolic resins as shown in the following formula:

[0014]

[Chemical formula 11]

[0015]

[Image Omitted] These may be used alone or in combination of two or more.

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 a specific epoxy resin, a polyfunctional phenol resin, tris (ortho, para-substituted phenyl) phosphine, a curing accelerator, and silica powder as essential components. For example, natural waxes,
Synthetic waxes, metal salts of linear fatty acids, acid amides, esters, mold release agents such as paraffin, flame retardants such as antimony trioxide, colorants such as carbon black, silane coupling agents, hardening accelerators, rubber-based or a silicone-based low stress imparting agent may be appropriately added and blended.

[0020] A general method for preparing the sealing resin composition of the present invention as a molding material is to prepare the above-mentioned components, namely, a specific epoxy resin, a polyfunctional phenolic resin, and tris (ortho- and para-substituted phenyl). Add the phosphine curing accelerator, silica powder, and other ingredients and mix 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.

[0022]

[Function] The encapsulating resin composition and semiconductor encapsulating device of the present invention achieve the intended purpose by reacting with a specific epoxy resin, a polyfunctional phenol resin, and a tris(ortho- and para-substituted phenyl)phosphine curing accelerator. This has been achieved. In other words, a predetermined amount of tris(ortho-, para-substituted phenyl)phosphine curing accelerator is added to control the gelation time and fluidity of the resin composition, which improves filling properties in thin-walled areas, improves moisture resistance, and provides excellent molding. gave gender. Furthermore, by reacting a specific epoxy resin with a 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.

[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% of a specific epoxy resin, 8% of trifunctional phenol resin of Chemical Formula 11, 0.3% of tris(2,6-diethoxyphenyl)phosphine as a curing accelerator, 74% of silica powder,
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 pulverized to produce a molding material (A).

Example 2 12% of a specific epoxy resin, 6% of trifunctional phenol resin of Chemical Formula 11, 0.3% of tris(2,6-diethoxyphenyl)phosphine as a curing accelerator, 81% of silica powder,
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 pulverized to produce a molding material (B).

Comparative Example 1 17% o-cresol novolac type epoxy resin, 8% novolac type phenol resin, 74% silica powder, 0.3% imidazole curing accelerator, ester wax
A molding material (C) was produced in the same manner as in Example 1 using 0.3% and 0.4% of the silane coupling agent.

Comparative Example 2 12% o-cresol novolac type epoxy resin, 6% novolac type phenol resin, 81% silica powder, 0.3% imidazole hardening accelerator, ester wax
A molding material (D) was produced in the same manner as in Example 1 using 0.3% and 0.4% of the silane coupling agent.

Molding materials (A) to (D) produced in Examples 1 to 2 and Comparative Examples 1 to 2 and semiconductor encapsulation devices produced using them were tested for moldability and moisture resistance. The results 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 molding material, 100°C in a mold at 175℃
The spiral flow distance was measured by applying a pressure of kg/cm2. *2: The time required for the molding material to gel was measured on a hot plate at 175°C. *3: The molding material was heated to 175°C. 100 in mold
Apply kg/cm2 force, 200μm, 300
The flow distance through a gap of μm and 10 μm was measured. *4: Using a molding material, QFP (14×14×1.
An 8 x 8 mm dummy chip 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. *5: Using molding material, a dummy chip was placed in a TO-220 type package. The number of filling defects in 500 packages was measured. *6: Using molding material, DIP-16 pin MOSI
For each of the semiconductor sealing devices that sealed the C test element or the TO-2 20 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 superior properties, 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 due to corrosion of the electrodes. An excellent and highly reliable semiconductor sealing device was obtained that did not generate leakage current due to disconnection or moisture.

Claims (2)

[Claims] Claim 1: (A) Epoxy resin represented by the following formula:
B) A polyfunctional phenolic resin represented by the following general formula (I) or (II) [Chemical formula 2] (wherein, n is 0 or an integer of 1 or more, and R is Cm
H2m+1, m represents 0 or an integer greater than or equal to 1)
, (C) Tris(ortho, para-substituted phenyl)phosphine represented by the following general formula [Chemical formula 3] (wherein, 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 (C) tris(ortho, para-substituted phenyl)phosphine is added to the resin composition in an amount of 0.0%.
A sealing resin composition characterized in that it contains 1 to 5% by weight. Claim 2: (A) Epoxy resin represented by the following formula: (where n represents 0 or an integer of 1 or more), (
B) A polyfunctional phenolic resin represented by the following general formula (I) or (II) [Chemical formula 5] (wherein, n is 0 or an integer of 1 or more, and R is Cm
H2m+1, m represents 0 or an integer greater than or equal to 1)
, (C) Tris(ortho, para-substituted phenyl)phosphine represented by the following general formula [Formula 6] (wherein, R1, R2, R3 represent an electron donating group or a hydrogen atom, and R1, R2, R3 (at least one of which is an electron-donating group) and (D) silica powder are essential components, and (C) tris(ortho, para-substituted phenyl)phosphine is added to the resin composition in an amount of 0.0%.
A semiconductor encapsulation device characterized in that a semiconductor device is encapsulated with a cured product of a encapsulation resin composition containing 1 to 5% by weight.