JPH11228788A - Semiconductor device and epoxy resin composition for semiconductor encapsulation - Google Patents

Abstract

(57) [Problem] To provide a semiconductor device excellent in solder heat resistance by improving the adhesiveness between a lead frame and a cured resin for sealing. SOLUTION: The lead is formed by resin-sealing a semiconductor element using a phenol resin having a melt viscosity at 150 ° C. of 5 poise or less and a special epoxy resin composition containing a specific adhesion-imparting agent. The adhesiveness between the frame and the cured resin for sealing is improved, and the generation of package cracks can be prevented even under severe conditions such as solder mounting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealed semiconductor device sealed with an epoxy resin composition, and more particularly to a semiconductor device excellent in solder heat resistance.

[0002]

2. Description of the Related Art Semiconductor devices such as transistors, ICs and LSIs are usually sealed by transfer molding using an epoxy resin composition. A typical example of this type of package is a dual in-line package (DIP). This DIP is of a pin insertion type, and is attached to a mounting board by inserting pins into the board.

However, as electronic devices have become smaller, lighter, and more sophisticated in recent years, the mounting density has been increased, and the surface mounting of semiconductor packages has been promoted.

[0004]

However, in a semiconductor device using the above surface mount type package,
Especially when the package itself has absorbed moisture before surface mounting, the vapor pressure of the absorbed moisture vaporized during solder mounting
There is a problem that cracks occur in the package.

As a countermeasure against such a problem, a method of reducing the moisture absorption of the package by lowering the moisture absorption of the resin skeleton and increasing the filling amount of the filler, or a method of curing the lead frame and the sealing resin by adding a silane compound. Although a method for improving the adhesiveness of the interface with an object has been proposed, satisfactory results have not yet been obtained. In recent years, lead-plated lead frames made of palladium have been applied from the viewpoint of global environment protection by shortening and rationalizing the manufacturing process of semiconductor devices and not using lead solder. In particular, the adhesiveness with the cured resin for sealing is not sufficient, which is a cause of deteriorating solder heat resistance.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a semiconductor device having good adhesiveness between a lead frame and a cured resin for encapsulation and having excellent solder heat resistance.

[0007]

In order to achieve the above-mentioned object, this semiconductor device encapsulates a semiconductor element using an epoxy resin composition containing the following components (A) to (D). Take the configuration. (A) Epoxy resin. (B) A phenol resin having a melt viscosity at 150 ° C. of 5 poise or less. (C) Inorganic filler. And (D) at least one type of adhesion imparting agent selected from organic titanium compounds, rosin-based resins, and indene-based resins.

That is, the present inventors have conducted a series of studies to achieve the above object. As a result, to prevent the occurrence of package cracks during mounting, a 150 ° C
As an additive that promotes adhesion to the lead frame, together with a phenol resin having a melt viscosity of 5 poise or less,
The present inventors have found that it is effective to use at least one kind of an adhesion-imparting agent selected from an organic titanium compound, a rosin-based resin, and an indene-based resin, and have reached the present invention.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The epoxy resin as the component (A) used in the present invention is not particularly limited, and a commonly used epoxy resin is used. Examples thereof include various epoxy resins such as orthocresol novolak type, phenol novolak type, bisphenol A type, biphenyl type and naphthalene type, and brominated epoxy resins. These can be used alone or in combination of two or more.

[0010] The phenolic resin as the component (B) comprises 1
The melt viscosity at 50 ° C. is not more than 5 poise. More preferably, it is 2 poise or less. When the melt viscosity exceeds 5 poise at 150 ° C, the melt viscosity of the obtained epoxy resin composition increases, the fluidity during molding decreases, unfilling and deformation of the bonding wire occur, and it is used for sealing the lead frame. The adhesiveness with the cured resin also decreases. The melt viscosity at 150 ° C. of the phenolic resin in the present invention is measured using an ICI viscometer. Such a phenolic resin refers to a resin having a failing hydroxyl group, such as a phenol novolak resin, a novolak resin such as a cresol novolak resin, a phenol aralkyl resin such as a xylylene-modified phenol resin, a terpene-modified phenol resin, and a dicyclopentadiene-modified phenol. Examples thereof include resins, but are not limited thereto. These phenol resins can be used alone or in combination.

The equivalent ratio [(a) / (b)] between the epoxy group (a) of the epoxy resin (A) and the phenolic hydroxyl group (b) of the phenol resin (B) is 0.5. It is preferably in the range of ~ 2.0.

Further, as the inorganic filler as the component (C), inorganic powders such as fused silica, crystalline silica, and alumina are used. These inorganic fillers can be used in either crushed or spherical form. These may be used alone or in combination of two or more. The amount of these inorganic fillers is determined from the balance between moldability and solder heat resistance.
It is preferable to contain 70 to 95% by weight in the epoxy resin composition. If the compounding amount is less than 70% by weight, the solder heat resistance tends to be insufficient, and if it exceeds 95% by weight, the melt viscosity of the epoxy resin composition increases, the fluidity at the time of molding decreases, and unfilled or bonding wires Tend to occur.

[0013] At least one kind of adhesion imparting agent selected from the group consisting of an organotitanium compound, a rosin-based resin and an indene-based resin, which is the component (D), has the effect of increasing the adhesion to the lead frame. It is used in the range of 0.1 to 5.0% by weight based on the whole composition. As the organic titanium compound used in the present invention, an alkoxide or a chelate compound of titanium is preferably used. Specifically, tetraisopropyl titanate, tetra-n-butyl titanate, tetrakis (2-ethylhexyl) titanate, tetrastearyl titanate, diisopropoxy bis (acetylacetonato) titanium, di-n-propoxy bis (triethanol) Aminato) titanium, isopropyl trisstearyl titanate, titanium acetylacetonate, titanium ethyl acetoacetate and the like. Examples of the rosin-based resin include a rosin-modified phenol resin and a rosin ester. Examples of the indene-based resin include an oligomer obtained by copolymerizing an indene such as indene or alkylindene and styrene, and an oligomer obtained by copolymerizing the above-mentioned indene, styrene and cumarone. The component (D) may also be used alone or in combination.

Further, the epoxy resin composition used in the present invention contains, if necessary, other additives conventionally used in addition to the components (A) to (D).

Examples of the other additives include a curing accelerator, a release agent, a flame retardant aid, a colorant, and a silane coupling agent.

Examples of the curing accelerator include amines, imidazoles, and organic phosphorus compounds such as phosphine compounds and quaternary phosphonium compounds, and they can be used alone or in combination.

Examples of the releasing agent include conventionally known long-chain carboxylic acids such as stearic acid and palmitic acid, metal salts of long-chain carboxylic acids such as zinc stearate and calcium stearate, and waxes such as carnauba wax and montan wax. Can be used.

Further, examples of the flame retardant auxiliary include antimony trioxide, antimony pentoxide and the like.

Further, examples of the coloring agent include carbon black.

The epoxy resin composition used in the present invention can be produced, for example, as follows. That is, first, the components (A) to (D) and the above-mentioned other additives are appropriately compounded, the mixture is melted and mixed in a heating state with a kneading machine such as a mixing roll, and the mixture is cooled to room temperature and then cooled. It can be manufactured by a series of steps of pulverizing by means and tableting as necessary.

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

In the description of the present invention, surface mounting has been described, but the effects of the present invention can be applied to a mounting method such as a pin insertion type.

Next, examples will be described together with comparative examples. First, the following compounds were prepared prior to the examples. <Epoxy resin> (a): o-cresol novolak type epoxy resin (epoxy equivalent: 195, softening point: 80 ° C) (b): novolak type brominated epoxy resin (epoxy equivalent: 275, softening point: 84 ° C) < Phenol resin> (c): Phenol novolak resin (hydroxyl equivalent: 10
6, softening point: 83 ° C, 150 ° C melt viscosity: 2 poise) (d): Phenol aralkyl resin represented by the formula (1) (hydroxy equivalent: 170, softening point 83 ° C, 150 ° C melt viscosity: 1.8)
Poise) (e): phenol novolak resin (hydroxyl equivalent: 10)
6, softening point: 91 ° C, 150 ° C, melt viscosity: 11 poise) <Inorganic filler> (f): Fused crushed silica (average particle size: 20 µm) <Adhesiveness imparting agent> (g): isopropyl tristearyl titanate ( h): Rosin ester (weight average molecular weight: 5800, hydroxyl equivalent: 170) (i): Indene resin (oligomer obtained by cationic polymerization of indene and styrene, indene / styrene polymerization ratio = 2/1 to 1/1) 2)

[0024]

Examples 1 to 5 and Comparative Examples 1 to 3 Next, the components shown in Table 1 were blended at a predetermined ratio, kneaded and cooled by a mixing roll machine, and then pulverized by pulverization. An epoxy resin composition was obtained. Using this epoxy resin composition, a semiconductor device was obtained by molding by semiconductor element transfer molding (molding at 175 ° C. × 90 sec, curing at 180 ° C. × 5 hours). This semiconductor device uses a package of QFP-160, and has a Ni: 50
Plating of 0 μm, Pd: 50 μm and Au: 8 nm on the outermost layer were used. The semiconductor device obtained in this manner was subjected to moisture absorption at 85 ° C./85% RH for 168 hours, then immersed in solder at 260 ° C., and the time until a package crack occurred was measured.

The adhesive strength was determined by molding the epoxy resin composition on a metal plate of the same material as the lead frame as shown in FIGS. 1 and 2, and determining the shear adhesive strength by the method shown in FIG. .

The sparral flow was evaluated under the conditions of 175 ° C. and 70 kg / cm 2 using a mold conforming to the EMMI standard. Table 1 shows the results of these measurements and evaluations.

[0027]

As described above, the semiconductor device of the present invention comprises a special epoxy resin composition containing a specific phenol resin (component (B)) and a specific adhesion-imparting agent (component (D)). By using a semiconductor element with resin sealing, the adhesion between the lead frame and the cured resin for sealing is improved, and the package crack does not occur even under severe conditions such as solder mounting. It can be seen that they have excellent solder heat resistance.

In particular, it shows good adhesiveness to a lead frame made of palladium which has recently been applied and has excellent solder heat resistance.

[0029]

Embedded image

[0030]

[Table 1]

[0031]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a method for producing an evaluation sample used for evaluating the adhesiveness of a cured resin body made of an epoxy resin composition.

FIG. 2 is a perspective view showing an evaluation sample obtained by the above manufacturing method.

FIG. 3 is an explanatory diagram showing a method for measuring a shearing force between a cured resin body and a frame.

[0032]

[Explanation of symbols]

 10: Upper mold 11: Middle mold 12: Lower mold 13: Measurement frame 15: Frustoconical resin cured body 16: Fixing jig

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01L 23/29 H01L 23/50 D 23/31 H01L 23/30 R 23/50 // (C08L 63/00 61:06 93: 04) (C08L 63/00 61:06 45:02)

Claims (4)

[Claims] 1. An epoxy resin, (B) a phenol resin having a melt viscosity at 150 ° C. of 5 poise or less, (C) an inorganic filler,
And (D) an epoxy resin composition containing at least one type of adhesion imparting agent selected from an organic titanium compound, a rosin-based resin or an indene-based resin, and a semiconductor in which a semiconductor element mounted on a lead frame is sealed. apparatus. 2. The semiconductor device according to claim 1, wherein the lead frame has Au plating on the outermost layer. 3. The semiconductor device according to claim 2, wherein the lower layer adjacent to the Au plating uses a lead frame having a Pd plating layer. 4. An epoxy resin, (B) a phenol resin having a melt viscosity at 150 ° C. of 5 poise or less, (C) an inorganic filler,
And (D) an epoxy resin composition for semiconductor encapsulation containing at least one kind of adhesion imparting agent selected from an organic titanium compound, a rosin-based resin and an indene-based resin.