JPH0563116A - Resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To improve heat-dissipating properties and moisture resistance by baking magnesium oxide at a temperature of 800-2800 deg.C and executing hydrophobic treatment as inorganic fillers. CONSTITUTION:Magnesium oxide blended as inorganic fillers is baked at a temperature of 800-2800 deg.C. 800-2000 deg.C is used as a more preferable baking temperature. The surface state of magnesium oxide is improved by such baking, thus enhancing the reactivity of magnesium oxide and a surface treating agent as compared to reactivity before baking. Consequently, since the hydrophobic treatment of magnesium oxide by the surface treating agent is conducted efficiently, the surface of magnesium oxide is covered sufficiently with the hydrophobic group of the surface treating agent, thus effectively inhibiting the absorption of the moisture of magnesium oxide. Accordingly, the heat-dissipating properties and moisture resistance of a semiconductor device are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-encapsulated semiconductor device in which a semiconductor element is encapsulated with a semiconductor encapsulating resin.

[0002]

2. Description of the Related Art A package of a semiconductor device has a main purpose of protecting a semiconductor element from an external environment. Currently, as a method of such package, an epoxy resin or a silicone resin is used. The mainstream is resin sealing using such as. The composition of the semiconductor encapsulating resin used for such resin encapsulation is composed of a resin component and an inorganic filler, and as a main component of the resin component, an epoxy resin or a silicone resin is generally used as described above. is there. On the other hand, as the inorganic filler, silica, antimony oxide, carbon, etc. are usually used.

By the way, in recent years, high integration of semiconductor elements,
With the increase in density, the amount of heat generated during operation of the semiconductor element tends to increase, with respect to the resin-encapsulated semiconductor device encapsulated by the semiconductor encapsulating resin as described above,
Further improvement of heat dissipation is required. In view of such requirements, JP-A-61-101524 and JP-A-63-
No. 227620 and Japanese Patent Application Laid-Open No. 2-56816 report a semiconductor encapsulating resin using magnesium oxide or aluminum nitride, which has a higher thermal conductivity, as an inorganic filler, instead of conventional silica or the like. However, since magnesium oxide and aluminum nitride have higher water absorption than silica and the like, in such a semiconductor sealing resin,
There has been a problem that it cannot withstand the more severe accelerated moisture resistance test required in the future with higher integration and higher density of semiconductor elements.

Further, Japanese Patent Application Laid-Open No. 57-55921 discloses a technique of treating magnesium oxide as an inorganic filler with a silane coupling agent to enhance the moisture resistance of a semiconductor encapsulating resin. Even with the sealing resin, sufficient moisture resistance could not be achieved.

[0005]

As described above, from the viewpoint of improving the heat dissipation of the resin-encapsulated semiconductor device, development of a semiconductor encapsulation resin using magnesium oxide or aluminum nitride as an inorganic filler has been promoted. However, such a semiconductor encapsulation resin has not yet been put to practical use because moisture resistance cannot be sufficiently obtained. An object of the present invention is to solve such problems and to provide a resin-sealed semiconductor device having high heat dissipation and sufficient moisture resistance.

[0006]

In order to achieve the above object, the first invention of the present application is such that a semiconductor element is encapsulated by a semiconductor encapsulating resin containing a resin, a curing agent and an inorganic filler as essential components. The resin-encapsulated semiconductor device according to claim 2, wherein the inorganic filler is magnesium-oxide which is hydrophobized after being baked at a temperature of 800 ° C. or more and 2800 ° C. or less. Is a resin-encapsulated semiconductor device in which a semiconductor element is encapsulated by a semiconductor encapsulating resin containing a resin, a curing agent and an inorganic filler as essential components, wherein the inorganic filler is hydrophobic with an inorganic surface treatment agent. It is a resin-encapsulated semiconductor device using aluminum nitride that has been subjected to chemical conversion treatment. That is, the resin-encapsulated semiconductor device of the present invention is characterized in that magnesium oxide or aluminum nitride as an inorganic filler of the semiconductor encapsulating resin is subjected to a hydrophobic treatment.

In the present invention, in order to obtain hydrophobized magnesium oxide, it is sufficient to treat the magnesium oxide calcined with a surface-treating agent having a hydrophobic group, and as such a surface-treating agent, A silane coupling agent system, a titanium coupling agent system, an organic aluminum agent system, a fluoroalkyl agent system, or the like can be used. At this time, it is more preferable to use a fine powder having a substantially spherical shape as the magnesium oxide from the viewpoint of workability at the time of sealing. On the other hand, in the present invention, in order to obtain hydrophobized aluminum nitride, aluminum nitride fine powder is immersed in an organic solvent together with an inorganic surface treating agent and mixed, and then the organic solvent is evaporated to 400 to
It may be dried at 500 ° C., and as such an inorganic surface treatment agent, a solid acid such as phosphoric acid, boric acid or silicic acid can be used.

The resin which can be used in the present invention is not particularly limited as long as it is one that is usually used as a semiconductor encapsulating resin. Epoxy resin, phenol resin, polyimide resin, maleimide resin, polyester resin, Thermosetting resin such as silicone resin, polycarbonate resin, acrylic resin, polyphenylene sulfide resin,
A thermoplastic resin such as Teflon resin may be used.

Further, as the curing agent which can be used in the present invention, phenol novolac resin such as phenol novolac resin, cresol novolac resin, novolac resin of bisphenol A, novolac resin of naphthol, 2,2 A phenol aralkyl resin such as a condensation polymerization compound of ′ -dimethoxy-p-xylene and phenols,
Examples thereof include polyoxystyrene such as polyparaoxystyrene, phthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic acid anhydride, and aromatic amines. In the present invention, one or more of these curing agents can be used.

In the present invention, a semiconductor encapsulating resin containing each of the above-mentioned components and, if necessary, a curing accelerator such as imidazole or its derivative, tertiary amine derivative, phosphine or its derivative, Natural wax, synthetic wax, metal salt of straight chain fatty acid, acid amide or ester, release agent such as paraffin, bromotoluene, hexabromobenzene, flame retardant such as antimony trioxide, colorant such as carbon black, A flexibility-imparting agent such as silicone oil or butadiene rubber may be appropriately blended.

The resin-encapsulated semiconductor device of the present invention can be obtained by encapsulating a semiconductor element using such a semiconductor encapsulating resin. In this case, as the semiconductor element, an integrated circuit (IC), a large scale integrated circuit (LSI),
Transistors, thyristors, diodes, etc. are not particularly limited, and semiconductor elements can be sealed by methods such as transfer molding, injection molding, compression molding, and casting.

[0012]

In the first aspect of the present invention, the surface condition of the magnesium oxide is modified by firing the magnesium oxide blended as the inorganic filler at a temperature of 800 ° C. or higher and 2800 ° C. or lower, and the original magnesium oxide content is obtained. High water absorption is reduced. At this time, if the firing temperature is too low, the surface state modification as described above becomes insufficient, and if the firing temperature is too high, the magnesium oxide melts. A more preferable firing temperature is 800 ° C or higher and 200.
It is 0 ° C or lower. Further, in the first invention of the present application, the surface state of the magnesium oxide is modified by the above-described firing, so that the reactivity between the magnesium oxide and the surface treatment agent is improved as compared with before the firing. Therefore, the hydrophobic treatment of magnesium oxide by the surface treatment agent is efficiently performed, so that the surface of the magnesium oxide is sufficiently covered with the hydrophobic group of the surface treatment agent, and the absorption of moisture by the magnesium oxide is effective. Can be suppressed to.

Further, in the second invention of the present application, the inorganic surface treatment agent is used for the hydrophobic treatment of the inorganic filler made of aluminum nitride instead of the organic surface treatment agent. That is, in the case of aluminum nitride compounded as the inorganic filler in the second invention of the present application, since the organic surface treatment agent which has been generally used conventionally has a weak adhesion to the surface of the aluminum nitride, the hydrophobic treatment is sufficiently performed. Could not be applied.
On the other hand, as a result of repeated studies by the present inventors, it was found that the inorganic surface treatment agent had good adhesion to the aluminum nitride surface. Therefore, in the second invention of the present application, by using the inorganic surface treatment agent, the surface of the aluminum nitride is sufficiently covered with the surface treatment agent, so that the hydrophobic treatment can be efficiently performed, and It is possible to effectively suppress the absorption of water.

[0014]

EXAMPLES Examples of the present invention will be described in detail below. Example 1

First, a magnesium oxide fine powder having an average particle size of 17 μm is prepared, and this magnesium oxide fine powder is mixed with 90 μm.
After firing at 0 ° C., a hydrophobic treatment was performed using an organoaluminum agent-based acetoalkoxyaluminum diisopropylate surface treatment agent (AL-M manufactured by Ajinomoto Co., Inc.) to give the inorganic filler according to this example. Obtained. In addition to this, 90
Fine magnesium oxide powder calcined at 0 ° C. but not subjected to hydrophobizing treatment (Comparative Example 1), magnesium oxide fine powder only hydrophobized without firing (Comparative Example 2), and ordinary spherical silica powder (Comparative Example 3) was prepared as an inorganic filler.

Next, regarding each of the above-mentioned inorganic fillers, a cresol novolac type epoxy resin (manufactured by Sumitomo Chemical Co., Ltd., 195XL-7) having an epoxy equivalent of 197, respectively.
4) Phenol with 9.52 wt% and a phenol equivalent of 104
Lunovolac resin curing agent (Showa High Polymer Co., BRG-5
56) 5.45 wt%, epoxy equivalent 278, brominated epoxy resin flame retardant (Nippon Kayaku Co., BREN-S)
2.0 wt%, triphenylphosphine 0.14 wt
%, Inorganic filler 80.55 wt%, carnauba wax release agent 0.26 wt%, antimony trioxide 1.25 wt
%, Carbon black 0.21 wt% and silicone oil 0.62 wt% were mixed at room temperature with a Henschel mixer, and further kneaded with a heating roll at 90 to 100 ° C. When silica powder was used as the inorganic filler, the compounding ratio was adjusted so that the volume ratio of the inorganic filler was the same as when the magnesium oxide was used as the inorganic filler.
Next, the obtained composition is cooled and pulverized to obtain a tablet, and the tablet is further preheated and then poured into a mold for transfer molding heated to 170 ° C. to be cured to obtain the semiconductor encapsulating resin according to the present invention. Molded.

The semiconductor encapsulating resin thus obtained is evaluated for thermal conductivity, moldability and moisture resistance, and the results are shown in Table 1. Here, the moldability is judged by the appearance of the obtained cured product, and the moisture resistance is determined under the conditions of 140 ° C., 4
The pressure was evaluated by a pressure cooker test.

As is apparent from Table 1, the semiconductor encapsulating resin according to this example has a higher thermal conductivity than the conventional one using silica as an inorganic filler (Comparative Example 3), and has excellent moldability. Excellent moisture resistance. On the other hand, it was confirmed that the semiconductor encapsulating resins using the fine magnesium oxide powders of Comparative Example 1 and Comparative Example 2 as the inorganic filler had cracks immediately after the start of the pressure cooker test and had extremely poor moisture resistance. It was Furthermore, instead of the above-mentioned organoaluminum agent type surface treatment agent, a silane coupling agent type epoxy silane coupling agent and a titanium coupling agent type Plane Act (manufactured by Ajinomoto Co.) are used respectively to seal the semiconductor. The characteristics of the obtained semiconductor encapsulating resin were evaluated in the case of molding the stop resin, and the same good results were obtained.

[0019]

[Table 1] Example 2

First, an aluminum nitride fine powder having an average particle size of 1.5 μm is prepared, and phosphoric acid (manufactured by Kanto Chemical Co., Inc.) is used as an inorganic surface treatment agent to subject the aluminum nitride fine powder to a hydrophobizing treatment. The inorganic filler according to the example was obtained. Separately from this, a fine aluminum nitride powder (Comparative Example 1) that has been subjected to a hydrophobic treatment using an organic surface treatment agent (epoxysilane coupling agent) and an aluminum nitride fine powder that has not been subjected to a hydrophobic treatment ( Comparative Example 2) and ordinary spherical silica powder (Comparative Example 3) were prepared as inorganic fillers.

Next, regarding each of the above-mentioned inorganic fillers, a cresol novolac type epoxy resin (manufactured by Sumitomo Chemical Co., Ltd., 195XL-7) having an epoxy equivalent of 197, respectively.
4) Phenol with 9.52 wt% and a phenol equivalent of 104
Lunovolac resin curing agent (Showa High Polymer Co., BRG-5
56) 5.45 wt%, epoxy equivalent 278, brominated epoxy resin flame retardant (Nippon Kayaku Co., BREN-S)
2.0 wt%, triphenylphosphine 0.14 wt
%, Inorganic filler 80.55 wt%, carnauba wax release agent 0.26 wt%, antimony trioxide 1.25 wt
%, Carbon black 0.21 wt% and silicone oil 0.62 wt% were mixed at room temperature with a Henschel mixer, and further kneaded with a heating roll at 90 to 100 ° C. Next, the obtained composition is cooled and pulverized to give a tablet, which is further heated 170
Pour into a transfer molding die heated to ℃,
The resin was cured to mold the semiconductor sealing resin according to the present invention.

The semiconductor encapsulating resin thus obtained was evaluated for thermal conductivity, moldability, moisture resistance and mechanical strength, and the results are shown in Table 1. Here, the moldability was judged by the appearance of the obtained cured product, the moisture resistance was evaluated by a pressure cooker test under the conditions of 140 ° C. and 4 atm, and the bending strength was measured as the mechanical strength.

As is clear from Table 2, the semiconductor encapsulating resin according to this example has a higher thermal conductivity than the conventional one using silica as an inorganic filler (Comparative Example 3), and has a good moldability, Excellent in moisture resistance and mechanical strength. On the other hand, in the semiconductor encapsulating resins using the aluminum nitride fine powders of Comparative Examples 1 and 2 as the inorganic filler, cracks were generated immediately after the start of the pressure cooker test,
It was confirmed that the moisture resistance was extremely poor.

[0024]

[Table 2]

[0025]

As described above in detail, according to the present invention, it is possible to provide a resin-sealed semiconductor device having high heat dissipation and sufficient moisture resistance. Therefore, it is possible to favorably cope with high integration and high density of semiconductor elements.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical display location C08K 9/04 KCP 7167-4J C08L 63/00 NKV 8416-4J

Claims (2)

[Claims] 1. A resin-encapsulated semiconductor device in which a semiconductor element is encapsulated by a semiconductor encapsulating resin containing a resin, a curing agent and an inorganic filler as essential components, wherein the inorganic filler is 800 ° C. or more and 2800 ° C. or less. A resin-encapsulated semiconductor device, characterized in that it uses magnesium oxide that has been subjected to a hydrophobizing treatment after being fired at the temperature. 2. A resin-encapsulated semiconductor device in which a semiconductor element is encapsulated with a semiconductor encapsulation resin containing a resin, a curing agent and an inorganic filler as essential components, wherein an inorganic surface treatment agent is used as the inorganic filler. A resin-encapsulated semiconductor device characterized by using a hydrophobized aluminum nitride.