JP3440449B2 - Sealing resin composition and semiconductor sealing device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to Pd and Pd-Au.
The present invention relates to an epoxy resin composition and a semiconductor encapsulation device which are excellent in reliability such as reflow crack resistance in a semiconductor package using a frame that has been pre-plated.

[0002]

2. Description of the Related Art In recent semiconductor devices, an increasing number of semiconductor packages employ a frame which is pre-plated with Pd, Pd-Au or the like instead of solder plating.

A conventional semiconductor device employing a pre-plating frame such as Pd or Pd-Au sealed with a resin composition composed of an epoxy resin, a novolac-type phenol resin and an inorganic filler has a structure in which an insert is bonded to a sealing resin. It had the drawback of being extremely poor in sex. Particularly, when the semiconductor device that has absorbed moisture is surface-mounted, peeling occurs between the encapsulating resin and the lead frame, or between the encapsulating resin and the semiconductor chip, which causes a significant deterioration in moisture resistance, resulting in disconnection due to electrode corrosion and leakage current due to moisture. As a result, the semiconductor device has a drawback in that long-term reliability cannot be guaranteed. Therefore, there has been a strong demand for the development of a material having excellent reflow resistance, little influence of humidity resistance, and little deterioration due to moisture resistance and good moldability.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above drawbacks and to meet the above demands.
Provided is a resin composition for encapsulation and a semiconductor encapsulation device, which has high adhesiveness to a preplating frame such as d or Pd-Au and is particularly excellent in reflow resistance and reliability after reflow, and has good moldability. Is what you are trying to do.

[0005]

Means for Solving the Problems The present inventor has conducted diligent research to achieve the above object, and as a result,
The present invention has been completed by discovering that the admixture with 4-dithiodimorpholine significantly improves the adhesiveness to Pd, Pd-Au, and other preplating frames and achieves the above objects, and completed the present invention. .

That is, the present invention relates to (A) epoxy resin,
(B) a novolac type phenol resin, (C) 4,4-dithiodimorpholine and (D) an inorganic filler are essential components, and (C) 4,4-dithiodimorpholine is added to the resin composition. A sealing resin composition comprising 0.001 to 0.1% by weight and the inorganic filler (D) in a proportion of 25 to 95% by weight, and this sealing resin composition A semiconductor encapsulation device characterized by encapsulating a semiconductor chip mounted on a frame pre-plated with Pd or Pd-Au with the cured product.

The present invention will be described in detail below.

The epoxy resin (A) used in the present invention is not particularly limited in molecular structure and molecular weight as long as it is a compound having at least two epoxy groups in its molecule, and it is generally used as a sealing material. You can broadly include what you have. Examples thereof include biphenyl-type and bisphenol-type aromatic resins, aliphatic resins such as cyclohexane derivatives, and epoxy novolac epoxy resins represented by the following general formula.

[0009]

[Chemical 1] (In the formula, R ¹ represents a hydrogen atom, a halogen atom or an alkyl group, R ² 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 can be mixed and used. The novolak type phenolic resin (B) used in the present invention is a novolak type phenolic resin obtained by reacting phenols such as phenol and alkylphenol with aldehydes such as formaldehyde and paraformaldehyde, and modified resins thereof such as epoxidation. Alternatively, a butylated novolak type phenol resin may be used. These resins may be used alone or in combination of two or more. The compounding ratio of the novolac type phenol resin is such that the equivalent ratio [(a) / (b)] of the epoxy group (a) of the epoxy resin and the phenolic hydroxyl group (b) of the novolac type phenol resin is in the range of 0.1 to 10. It is desirable to be within. If the equivalent ratio is less than 0.1 or exceeds 10, the heat resistance, moisture resistance, molding workability and electrical properties of the cured product deteriorate, which is not preferable. Therefore, it is preferable to limit it within the above range.

The (C) 4,4-dithiodimorpholine used in the present invention is represented by the following structural formula.

[0011]

[Chemical 2]

The compounding ratio of 4,4-dithiodimorpholine is preferably 0.001 to 0.1% by weight based on the total resin composition. If this ratio is less than 0.001% by weight, Pd
And Pd-Au and the like have no effect on improving the adhesive strength to the preplating frame, and when it exceeds 0.1% by weight, it adversely affects the curing of the sealing resin and is not suitable for practical use.

Examples of the inorganic filler (D) used in the present invention include silica powder, alumina powder, antimony trioxide, talc, calcium carbonate, titanium white, clay, mica, red iron oxide, glass fiber and the like. Alternatively, two or more kinds can be mixed and used. Among these, silica powder and alumina powder are particularly preferable and often used. The blending ratio of the inorganic filler is preferably 25 to 95% by weight based on the total resin composition. If the proportion is less than 25% by weight, heat resistance, moisture resistance,
Solder heat resistance, mechanical properties and moldability are poor, and if it exceeds 95% by weight, dryness becomes large, and moldability is poor and it is not suitable for practical use.

The encapsulating resin composition of the present invention contains an epoxy resin, a novolac type phenolic resin, 4,4-dithiodimorpholine and an inorganic filler as essential components, but within a range not deviating from the object of the present invention, Further, if necessary, for example, natural waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, esters, release agents such as paraffins, chlorinated paraffins, brominated toluene, hexabromene benzene, and trichlorobenzene. Flame retardants such as antimony oxide, colorants such as carbon black and red iron oxide, various curing accelerators and the like can be appropriately added and blended.

As a general method for preparing the encapsulating resin composition of the present invention as a molding material, epoxy resin, novolac type phenol resin, 4,4-dithiodimorpholine, inorganic filler and other components are used. Can be mixed and sufficiently mixed with a mixer or the like, and then subjected to a melt mixing treatment with a hot roll or a mixing treatment with a kneader or the like, followed by cooling and solidifying, and pulverizing to an appropriate size to obtain a molding material. . When the molding material thus obtained is applied to sealing, coating, insulation, etc. of electronic parts or electric parts such as semiconductor devices, excellent properties and reliability can be imparted.

The semiconductor encapsulation device of the present invention can be easily manufactured by encapsulating a semiconductor chip using the encapsulating resin obtained as described above. The most general method of sealing is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting or the like is also possible. The encapsulating resin composition is heated and cured during encapsulation, and finally a semiconductor encapsulating device encapsulated with the cured product of the composition is obtained. Curing by heating is 150 ° C
It is desirable to heat and cure the above. The semiconductor device to be sealed is not particularly limited to, for example, an integrated circuit, a large scale integrated circuit, a transistor, a thyristor, a diode and the like.

[0017]

In the encapsulating resin composition and semiconductor encapsulating device of the present invention, the intended properties can be obtained by using 4,4-dithiodimorpholine as the resin component.
That is, it is possible to improve the adhesive force with the preplating frame such as Pd or Pd-Au, prevent the adhesiveness between the insert and the sealing resin after surface mounting from being deteriorated, and guarantee the long-term reliability. I was able to.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, “%” means “% by weight”.

Example 1 Cresol novolac epoxy resin (epoxy equivalent 195
) 12.5%, novolac type phenolic resin (phenol equivalent 104) 6.7%, 4,4-dithiodimorpholine 0.01% shown in the following chemical formula 3,

[0020]

[Chemical 3] 80% fused silica powder, 0.2% ester waxes, 0.19% curing accelerator and 0.4% silane coupling agent are mixed at room temperature, then kneaded at 90-95 ° C and cooled and ground to produce molding materials. did. This molding material was transfer-injected into a mold heated to 170 ° C. and cured to form a molded product (sealed product). The molded product was tested for properties such as moisture resistance, and the results are shown in Table 1. Particularly, the remarkable effect of the present invention was recognized in the moisture resistance.

Example 2 Biphenyl type epoxy resin (epoxy equivalent 213) 5.0%
And phenol aralkyl resin (phenol equivalent 175)
4.15%, 0.01 of 4,4-dithiodimorpholine of the above chemical formula 3
%, Silica powder 90%, ester waxes 0.2%, curing catalyst 0.14% and silane coupling agent 0.5% were mixed, kneaded and pulverized in the same manner as in Example 1 to produce a molding material. A molded product was prepared in the same manner as in Example 1 and characteristic tests such as moisture resistance were conducted. The results are shown in Table 1.
Particularly, the remarkable effect of the present invention was recognized in the moisture resistance.

Example 3 Biphenyl type epoxy resin (epoxy equivalent 213) 5.0%
And phenol aralkyl resin (phenol equivalent 175)
4.15%, 0.005 of 4,4-dithiodimorpholine of the above chemical formula 3
%, Curing catalyst 0.14%, silane coupling agent 0.5%, silica powder 90% and ester wax 0.2% were mixed, kneaded and pulverized in the same manner as in Example 1 to produce a molding material.
A molded product was prepared in the same manner as in Example 1 and characteristic tests such as moisture resistance were conducted. The results are shown in Table 1. Particularly, the remarkable effect of the present invention was recognized in the moisture resistance.

Comparative Example Cresol novolac type epoxy resin (epoxy equivalent 19
5) 12.5%, novolac type phenolic resin (phenol equivalent 104) 6.7%, silica powder 80%, hardening accelerator 0.19
%, Ester waxes 0.2% and silane coupling agent 0.4% were mixed and a molding material was manufactured in the same manner as in Example 1. A molded article was formed using this molding material, and various characteristics of the molded article were tested in the same manner as in Example 1,
The results are shown in Table 1.

[0024]

[Table 1] * 1: A molded product with an adhesion area of 4 mm ² was made by transfer molding, and this was post-cured at 175 ° C for 8 hours, and the shear adhesive strength was determined. * 2: A molded product was made by transfer molding, post-cured at 175 ° C for 8 hours, and measured using a thermal instrument analyzer. * 3: A silicon chip (test element) having two or more aluminum wirings is adhered to a Pd pre-plating frame using a molding material, and transfer molding is performed at 175 ° C for 2 minutes to produce QFP-208P, 2.8. A molded product of mm ^t was prepared and post-cured at 175 ° C for 8 hours. The molded product obtained in this way was previously subjected to 85 ° C, 40% RH, 168
After the moisture absorption treatment for a certain period of time, it was passed through an IR reflow furnace at Max 240 ° C. four times. After that, PCT was performed in saturated steam at 127 ° C. and 2.5 atm, and the breakage due to corrosion of aluminum was evaluated as defective.

[0025]

As is clear from the above description and Table 1, the encapsulating resin composition and semiconductor encapsulating device of the present invention have excellent adhesiveness to Pd and Pd-Au plated inserts, and IR reflow. It does not peel off even afterwards and has excellent moisture resistance, and as a result, it is possible to remarkably reduce the occurrence of wire breakage due to electrode corrosion and the occurrence of leak current due to moisture,
Moreover, reliability can be guaranteed for a long period of time.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI H01L 23/31 (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 63/00-63/10 C08G 59/62 C08K 5/46 H01L 23/29

Claims (2)

(57) [Claims] 1. An epoxy resin (A), a novolac type phenolic resin (B), 4,4-dithiodimorpholine (C) and an inorganic filler (D) as essential components, which are added to the resin composition as described above. C) of 4,4-dithiodimorpholine in an amount of 0.001 ~
A resin composition for encapsulation, comprising 0.1% by weight and the inorganic filler (D) in a proportion of 25 to 95% by weight. 2. An epoxy resin (A), a novolac type phenolic resin (B), 4,4-dithiodimorpholine (C) and an inorganic filler (D) are essential components, and the resin composition is C) of 4,4-dithiodimorpholine in an amount of 0.001 ~
Mounted on a frame pre-plated with Pd or Pd-Au by a cured product of the encapsulating resin composition containing 0.1% by weight and the inorganic filler (D) in a proportion of 25 to 95% by weight. A semiconductor encapsulation device characterized by encapsulating the formed semiconductor chip.