JP3537859B2 - Semiconductor device and epoxy resin composition used therein - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reliable semiconductor device.

[0002]

2. Description of the Related Art Semiconductor elements such as transistors, ICs, and LSIs have been sealed in ceramic packages or the like to form semiconductor devices. However, recently, from the viewpoint of cost and mass productivity, plastic packages have been developed. Resin sealing using a die has become mainstream. Epoxy resin compositions have conventionally been used for this type of resin sealing and have achieved good results. However, due to technological innovation in the field of semiconductors, the degree of integration has been increased and the device size has been increased,
With the progress of finer wiring, packages are also becoming smaller and thinner, and accordingly, the sealing material is required to have higher reliability (reduction of thermal stress of the obtained semiconductor device, reliability of moisture resistance). , Reliability against thermal shock tests, etc.) are required. In particular, in recent years, the size of semiconductor elements has been increasing, and a thermal cycle test (“TCT test”), which is an accelerated test for evaluating the performance of a cured resin composition for semiconductor encapsulation, has been conducted.
) Is required. Also, surface mounting has become the mainstream semiconductor package mounting method. For this reason, cracks and blisters occur in the package even when the semiconductor package is absorbed and then immersed in a molten solder. There is a demand for a characteristic that does not. In this regard, it has been studied to modify the epoxy resin with a silicone compound to reduce the thermal stress in order to improve the properties evaluated by the TCT test. Also, to improve the crack resistance during solder immersion, the improvement of the adhesion with the lead frame has been studied.
The effect is still not enough.

[0003]

As described above, the conventional semiconductor device encapsulated with the epoxy resin composition has sufficient characteristics of package cracks caused by the TCT test and crack resistance during solder immersion. Was not. For this reason, it is strongly desired to improve both of the above characteristics so as to be able to cope with an increase in the size of a semiconductor element and surface mounting due to the above technical innovation. The present invention
In view of such circumstances, it is an object of the present invention to provide a semiconductor device having improved characteristics evaluated by a TCT test and having excellent crack resistance during immersion in a solder melt.

[0004]

In order to achieve the above object, the present invention provides a structure in which a semiconductor element is sealed using an epoxy resin composition containing the following components (A) to (C). Take. (A) An epoxy resin represented by the following general formula [Formula 7].

Embedded image (B) A curing agent which is a phenolic resin represented by the following general formulas [Chemical Formula 8] and [Chemical Formula 9]. (C) an inorganic filler.

Next, the present invention will be described in detail.

The semiconductor device used in the present invention is obtained by using a special epoxy resin (A) component, a curing agent (B) component and an inorganic filler (C) component.
Usually, it is in the form of a powder or a tablet obtained by compressing the powder.

[0007] The novel epoxy resin of the component (A) is a polyglycidyl ether represented by the above formula [7],
The softening point is preferably 70 to 160 ° C, and the ICI viscosity at 150 ° C is preferably 0.01 to 1.0 poise. Particularly preferred are those in which a 2,3-epoxypropoxy group is bonded to the 1- and 4-positions of the benzene ring, and a tert-butyl group is bonded to the 2- and 5-positions, and have softening points of 100 to 150 ° C and 150 ° C. ICI at
It has a viscosity of 0.01 to 0.5 poise. The new epoxy resin may be used alone or in combination with a general epoxy resin. In that case, bisphenol A is used as a general epoxy resin component.
Mold, phenol novolak type and cresol novolak type epoxy resin. When the above general epoxy resin is used in combination, it is preferable to set the epoxy resin of the above [Chemical Formula 7] to 50% by weight (hereinafter abbreviated as “%”) or more of the entire epoxy resin component. That is, if the content of the novel epoxy resin is 50% or less of the entire epoxy resin component, a package crack by a TCT test or a package crack during solder immersion tends to occur.

The curing agent (B) used together with the epoxy resin (A) having the above-mentioned special skeleton structure is not particularly limited, and conventionally known curing agents can be used. For example, an acid anhydride-based curing agent such as pyromellitic anhydride, a polyamine-based curing agent such as phenylenediamine, a polymercaptan-based curing agent such as trioxane trimethylene mercaptan, and a phenol resin are used. Particularly, a phenol resin is preferably used, and examples thereof include phenol novolak, cresol novolak, and naphtho-novolak. These phenol resins generally have a softening point of 40 to 120 ° C and a hydroxyl equivalent of 70 to 280.
Are preferred. Particularly preferred are those having a softening point of 50 to 90 ° C and a hydroxyl equivalent of 100 to 220. Specifically, the following general formulas [formula 8] and [formula 9] are exemplified.

Embedded image

Embedded image

The mixing ratio of the special epoxy resin and the curing agent is such that the hydroxyl group in the phenol resin is 0.8 to 1.2 equivalent per 1 equivalent of the epoxy group in the special epoxy resin. Is preferred. More preferably,
0.9 to 1.1 equivalents.

Inorganic filler (C) used together with the novel epoxy resin (A) component and the curing agent (B) component
The components are not particularly limited, and include generally used quartz glass powder, talc, silica powder, alumina powder, calcium carbonate, carbon black powder and the like. In particular, it is preferable to use silica powder. The content of such an inorganic filler, in the case of silica powder,
It is preferable to set it to 50% by weight or more of the entire epoxy resin composition. It is particularly preferably at least 80% by weight. That is, when the content of the silica powder is less than 50% by weight, the effect of containing the filler tends to decrease. That is, it is difficult to reduce the coefficient of linear expansion of the cured epoxy resin composition, and the strength of the epoxy resin composition decreases.
This is because package cracks caused by the test and problems such as package cracks at the time of solder immersion tend to occur due to an increase in the water absorption of the cured product.

The epoxy resin composition used in the present invention contains, in addition to the above-mentioned epoxy resin (A) component, curing agent (B) component and inorganic filler (C) component, a stress reducing agent if necessary. Silicone rubbers and olefin rubbers are generally used, and conventionally known tertiary amines, quaternary ammonium salts, imidazoles, phosphorus compounds and boron compounds can be used alone or in combination. . Among them, phosphorus compounds are preferably used, and triphenylphosphine is particularly preferable.
Furthermore, flame retardants such as antimony trioxide and phosphorus compounds,
Pigments such as carbon black and titanium oxide, release agents such as paraffin and aliphatic esters, and coupling agents such as silane coupling agents can be used.

The epoxy resin composition used in the present invention can be produced, for example, as follows. That is, the above-mentioned novel epoxy resin, curing agent and inorganic filler, and if necessary, a low-stressing agent, a curing accelerator, a flame retardant, a pigment, a release agent and a silane coupling agent are blended in a predetermined ratio. Next, these mixtures were melted and kneaded in a heated state using a kneader such as a mixing mill, and the like.
After cooling this to room temperature, it is ground by known means,
The desired epoxy resin composition can be obtained by a series of steps of tableting as necessary.

Using such an epoxy resin composition,
The method of sealing the semiconductor element is not particularly limited, and can be performed by a known molding method such as ordinary transfer molding.

[0014]

As described above, the semiconductor device of the present invention uses the special epoxy resin composition containing the above-mentioned novel epoxy resin, hardener and inorganic filler. To improve the life. In addition, even when immersed in a solder melt after absorbing moisture, package cracks are unlikely to occur. Due to this, by the sealing with the special epoxy resin composition,
In a large semiconductor device having 80 pins or more, particularly 160 pins or more, or a semiconductor element having a long side of 40 mm or more, the above-described high reliability can be obtained, which is a great feature.

Next, examples will be described together with comparative examples. Prior to the preparation of the epoxy resin composition, the following epoxy resin A, epoxy resin B, epoxy resin C and phenol resin D, phenol resin E, phenol resin F and phenol resin G are prepared. did. In the following chemical formula, Gly represents a glycidyl group. "Epoxy resin A"

Embedded image "Epoxy resin B"

Embedded image "Epoxy resin C"

Embedded image "Phenol resin D"

Embedded image "Phenol resin E"

Embedded image "Phenol resin F"

Embedded image "Phenol resin G"

Embedded image

[0016]

The present invention will be described below with reference to examples. Examples 1 to 9 and Comparative Examples 1 to 4 The above-mentioned resins and other raw materials were blended at the ratios shown in Tables 1 to 4 below and mixed in a mixing machine (at a temperature of 100 ° C.). ), And the mixture was melt-kneaded for 3 minutes, cooled and solidified, and then pulverized to obtain a desired powdery epoxy resin composition.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

Using the epoxy resin compositions obtained in the above Examples and Comparative Examples, a semiconductor element was subjected to transfer molding (transfer pressure 75 kg / cm ² , 17
The semiconductor device was obtained by holding at 5 ° C. for 2 minutes and curing at 175 ° C. for 5 hours). This package is an 80-pin 4-way flat package (80-pin QFP, size:
20 × 14 × 2mm) and the die pad size is 8 ×
8 mm. About the semiconductor device obtained in this way, -50 ° C / 5 minutes to 150 ° C / 5 minutes (liquid refrigerant)
Was subjected to a TCT test. Further, a test was conducted in which the semiconductor device was left in a thermostat at a relative humidity of 85 ° C./85% RH to absorb moisture, and then immersed in a solder melt at 260 ° C. for 10 seconds. The results are shown in Tables 5 to 8 below.

[Table 5]

[Table 6]

[Table 7]

[Table 8]

From the results of Tables 5 to 8, it can be seen that the TCT test of the example product and the crack resistance upon immersion in the solder melt are significantly superior to the comparative example of the conventional product. it is obvious.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 59/20-59/32 C08G 59/62 H01L 23/29

Claims (2)

(57) [Claims] 1. A semiconductor device in which a semiconductor element is sealed using an epoxy resin composition containing the following components (A) to (C). (A) An epoxy resin represented by the following general formula [Formula 1]. Embedded image (B) a curing agent which is a phenolic resin represented by the following general formula [2] or [3]; Embedded image Embedded image (C) an inorganic filler. 2. An epoxy resin composition containing the following components (A) to (C). (A) An epoxy resin represented by the following general formula [Formula 4]. Embedded image (B) A curing agent which is a phenolic resin represented by the following general formula [5] or [6]. Embedded image Embedded image (C) an inorganic filler.