JPH03195047A - Semiconductor-element housing container - Google Patents

Abstract

PURPOSE:To maintain a mechanical strength and a thermal expansion property close to Si and to enhance a light-shielding property by a method wherein this container is constituted of a silicon nitride sintered substance containing a specific amount of iron. CONSTITUTION:A container is constituted of a silicon nitride (Si3N4) sintered substance which contains 0.2 to 1.5wt.% of iron. That is to say, a silicon nitride powder 11a is pressurized and molded so as to form a hollow in the center; after that, a conductor paste 12a composed of a high-melting metal such as tungsten or the like is printed on the hollow part. Then, this assembly is degreased in an atmosphere of nitrogen; after that, it is baked under normal pressure, it is baked by using a hot-press or it is baked by a gas pressure; a silicon nitride sintered substance 11b having a conductor paste 12b is obtained; a semiconductor-element housing container is constituted of the substance. Thereby, its light-shielding property is excellent, its density is large, its coefficient of thermal expansion is close to that of a semiconductor element. As a result, a crack is not produced at the element; a package whose breakage-resistant strength is excellent can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a container that houses a semiconductor element and protects the semiconductor element from the outside world.

[Prior Art] [Problem to be Solved by the Invention] In recent years, with the increasing density, speed, and cost reduction of electronic components, pancage materials have lower dielectric constants and superior thermal conductivity, and are becoming more and more suitable for mounted semiconductors. There is a need for a material that has a coefficient of thermal expansion close to that of the device, has high mechanical strength, and can be manufactured at low cost. On the other hand, since the commonly used material is an alumina sintered body, there is a problem in that the difference in coefficient of thermal expansion between the material and the semiconductor element is large, causing cracks in the element. Furthermore, when aluminum nitride is used instead of alumina, it has high thermal conductivity, but the color is white or translucent white, and when applied to a pan cage, it has a negative effect on IC memory due to the transmission of ultraviolet rays. . Furthermore, black materials have been required for optical functional parts such as line sensors, but to date no products have been created that meet this requirement.

The present invention aims to solve this problem.

[Means to solve the problem]

The present invention was developed as a result of intensive studies, focusing on the fact that the silicon nitride sintered body is gray in color, has a coefficient of thermal expansion close to that of semiconductor elements, has high heat resistance, and has high mechanical strength.
) containing 0.2 to 1.5% by weight of silicon nitride (Si3
It has been found that a container made of a sintered body (Nn) satisfies the above requirements.

[Effect]

In the present invention, since the container is made of a sintered body mainly composed of silicon nitride, it has a coefficient of thermal expansion close to that of silicon regardless of the firing method, and has excellent mechanical strength and light blocking properties. It has excellent properties.

To improve the light-shielding properties of silicon nitride, Fe should be added to 0.2
It is essential to contain ~1.5% by weight.

However, if the content of Fe is less than 0.2%, the effect will be poor, and if it exceeds 1.5% by weight, the insulation properties will deteriorate too much and this is not suitable.

When carrying out the present invention, even if AlzOi and Y2O2 are added at the same time, it has nothing to do with the light-shielding properties of the sintered body.

Note that it is also possible to mix powders of ceramics other than silicon nitride in the sintered body, but by making the amount of silicon nitride in the sintered body contain 75% by weight or more, It is possible to maintain mechanical strength and thermal expansion close to that of Si.

[Example] Examples 1 to 9 and Comparative Examples 1 to 2: Si3N4, Al2O2, Y2O with an average particle size of 0.7 μm
3 powder and Fe (in the form of methoxide) were mixed in the proportions shown in Table 1, ethyl alcohol was added thereto, wet mixed in an alumina trommel, an organic binder for powder molding such as ethyl cellulose was added, and ethyl alcohol was added. The ceramic powder was prepared by volatilization.

Next, the powder prepared above was heated to about 1500 k at room temperature.
After molding under pressure at g/ctM, it was degreased.

Next, this was subjected to normal pressure firing, hot pressing, or gas pressure firing. The blending ratio and firing conditions are as shown in Table 1. All of the sintered bodies shown in Examples were dense and had a beautiful black color with excellent light blocking properties.

The density, coefficient of thermal expansion, bending strength, and electrical resistance were measured and found to be satisfactory. On the other hand, in Comparative Example 1, the color was gray, but in Comparative Example 2, it was black. However, the density, coefficient of thermal expansion, bending strength, and electrical resistance were all unsatisfactory. These Examples and Comparative Examples are collectively shown in Table 1.

Next, pancages were created using the silicon nitride sintered bodies of Examples and Comparative Examples obtained by the above method. The process is as follows.

FIGS. 1(a) to 1(f) are cross-sectional views showing the manufacturing process of a ceramic package.

In the figure, silicon nitride powder is first pressure-molded into the shape shown in FIG. 1(a) with a depression in the center, and then a conductor paste 12a made of a high melting point metal such as tungsten or molybdenum is applied to the depression. print on top. Next, this was degreased at 600°C for 3 hours in a nitrogen atmosphere, and then baked at normal pressure.
Figure 1 (b) after hot press firing or gas pressure firing.
As shown in FIG.
A silicon nitride sintered body (substrate) 11b having the following properties was obtained. This constitutes the semiconductor element storage container. Next, as shown in FIG. 1(C), a silicon nitride sintered body (substrate) llb
A glass layer 13 as an adhesive layer was applied to the upper surface of the bonding surface. Here, a low thermal expansion glass of PbO.8□03 type was used as the adhesive glass layer. Next, as shown in FIG. 1(d), the lead frame 14 was placed on the glass layer 13 and the glass was melted and bonded by heating. Thereafter, as shown in FIG. 1(e), a semiconductor layer was placed on the conductive portion 12b. chip 1
5 was mounted, and then the chip 15 and lead frame 14 were connected using bonding wires 16. Incidentally, a plan view in this state is shown in FIG. Next, Figure 1 (
As shown in f), a ceramic camp 18 made of silicon nitride with a glass layer 17 adhered to the lower bonding surface is placed in contact with the glass layer 13 of the substrate, and in this state, the substrate 1 is
The substrate 11b and the ceramic cap 18 were bonded by pressing the ceramic cap 18 to the substrate 11b, and firing and fusing the glass layers 13 and 17 with the lead frame in between.

The ceramic packages thus formed were subjected to a thermal shock temperature cycle test according to the test conditions of the MIL standard (MIL 883C) shown in the table below, and then electrical insulation and airtightness were evaluated, and all nine types of examples were found to be good. It exhibits good electrical insulation and airtightness with leakage of 100-8a.
It was good at less than t-cc/sec.

Thermal shock test: MILloll, condition 0°10
0 cycle temperature cycle: MILlolo, condition C, 5
00 Cycles [Effects of the Invention] According to the present invention, the semiconductor container is formed of a silicon nitride sintered body containing 0.2 to 1.5% by weight of Fe component, so it has excellent light-shielding properties and sufficient light-shielding properties. It has electrical insulation properties, high density, and a coefficient of thermal expansion close to that of semiconductor elements, so
It is possible to provide a package that does not cause cracks in the element and has excellent bending strength.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the manufacturing process of a ceramic package according to the present invention, and FIG. 2 is a plan view of a state in which a semiconductor chip is mounted. 11b=substrate, 12b: conductive part Fig. 1

Claims (1)

[Claims] A semiconductor device storage container characterized by being made of a silicon nitride (Si_3N_4) sintered body containing 0.2 to 1.5% by weight of iron (Fe).