JPH01297845A - Package for housing glass-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To bond outer lead terminals and a cover to an insulating substrate firmly by a method wherein the insulating substrate is composed of a specific sintered unit and a specific metal layer is formed on the surface of the substrate. CONSTITUTION:An insulating substrate 1 is composed of a silicon carbide sintered unit. If an Al metal layer 4 is provided over the whole surface of the substrate 1, the layer 4 is firmly bonded to the substrate 1 by the reaction between free silicon and Al. On the other hand, as the Al metal layer 4 has a high wettability with glass, outer lead terminals 7 and a cover 3 are firmly bonded to the insulating substrate 1 with glass layers 5, so that the reliability of a glass-sealed semiconductor device housing package can be improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a package for housing semiconductor elements, and more particularly to a glass-sealed package for housing semiconductor elements using a silicon carbide sintered body as a container. It is something.

[Conventional technology]

Conventionally, pancakes for storing semiconductor devices have been made of alumina ceramics, etc., which have a hollow space approximately in the center of the top surface for accommodating the semiconductor device, and have a metallized metal layer made of a high melting point metal such as tungsten (W) on the top surface. It is composed of an insulating base made of aluminum, an external lead terminal made of Kovar (Fe-Ni-Co alloy), etc. for electrically connecting the semiconductor element to an external wiring circuit, and a lid. A sealing glass layer made of low-melting point glass is preliminarily formed on the opposing main surfaces of the glass, and external lead terminals are sandwiched between the glasses and the glass layers are melted and integrated to place the semiconductor element inside. It is hermetically sealed and becomes a semiconductor device.

However, in recent years, high-density, large-sized semiconductor integrated circuit devices, such as LSIs, generate an extremely large amount of heat during operation, and the conventional alumina-based semiconductor device storage package is Conductivity is 17W/m-
Since the temperature is very low, there is a problem that heat dissipation is insufficient and the heat generated by the semiconductor element causes the element itself to malfunction.

Therefore, in order to eliminate the above-mentioned drawbacks, it has been proposed to use a silicon carbide sintered body with extremely high thermal conductivity, such as a silicon carbide sintered body containing helium (Be), as the base of a package for housing semiconductor elements. (Unexamined Japanese Patent Publication No. 1983-
156980).

[Problem to be solved by the invention]

However, unlike alumina ceramics, silicon carbide sintered bodies do not contain glass components, so when external lead terminals and lids are attached and fixed to an insulating base via sealing glass, The reactivity and wettability between the glass component and the silicon carbide sintered body are extremely poor, making it impossible to securely attach the external lead terminals and the lid to the insulating base made of the silicon carbide sintered body. As a result, even if a small external force was applied to the lid, external lead terminals, etc., the external lead terminals and lid would peel off from the insulating base, resulting in a significant decrease in reliability as a package for housing semiconductor elements. .

[Purpose of the invention]

The present invention was devised in view of the above-mentioned drawbacks, and its purpose is to improve the adhesion between the insulating base and the sealing glass, and to firmly and securely attach the insulating base to the external lead terminals and the lid. It is an object of the present invention to provide a glass-sealed semiconductor element storage pancase with extremely high properties.

[Means to solve the problem]

The present invention provides a glass structure in which an external lead terminal is sandwiched between an insulating base and a lid having glass layers adhered to their opposing main surfaces, and a semiconductor element is hermetically sealed inside by melting and integrating the glass layers. The sealed package for housing a semiconductor element is characterized in that the insulating base is formed of a sintered body of silicon carbide, and a metal layer made of aluminum (AI) is provided on the entire upper surface of the insulating base.

〔Example〕

Next, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

FIG. 1 is a cross-sectional view showing an example of a flat package as a semiconductor element storage package of the present invention.

In the figure, 1 is an insulating base made of a silicon carbide sintered body, and 2 is a lid made of a mullite sintered body. The insulating base 1 and the lid 2 constitute an insulating container 3.

The insulating substrate 1 includes, for example, silicon carbide (SiC) powder as a main component, beryllia (BeO), and boron carbide (B4C).
), alumina (AlzO:+) and other subcomponents are added and mixed with a binder, and after granulation using a mesh pass or the like, a thin plate-like compact is obtained by press forming, and the compact is heated at a high temperature. It is produced by firing.

Glass layers 5.5a for sealing are formed on opposing main surfaces of the insulating base 1 and lid 2, respectively, as will be described later, and the glass layers 5, 5a are heated and melted to integrate them. By doing so, the semiconductor element 6 is hermetically sealed within the insulating container 3.

The glass layers 5 and 5a are made of, for example, low melting point glass, and a glass paste obtained by adding an appropriate solvent to the glass powder is applied to the insulating substrate 1 and the lid 2 by a conventionally well-known thick film printing method. It is deposited and formed on the facing main surface to a desired thickness.

Further, on the upper surface of the insulating substrate 1, under the glass layer 5, a metal layer 4 made of aluminum is provided by a known vapor phase growth method such as an ion blasting method or a sputtering method. This serves to firmly attach the sealing glass layer 5 to the base 1.

The metal layer 4 is a very thin silicon (Si) oxide film layer formed on the surface of the silicon carbide sintered body forming the insulating substrate 1, or the free silicon in the silicon carbide sintered body reacts with aluminum. The glass layer 5 can be firmly bonded to the insulating substrate 1 made of a silicon carbide sintered body because of the strong adhesion and the fact that aluminum has excellent reactivity and wettability with glass components. it is conceivable that.

A conductive material such as aluminum (AI), copper (Cu), Kovar (Fe-
An external lead terminal 7 made of metal such as Ni-Co) is arranged, and each electrode of the semiconductor element 6 is electrically connected to the external lead terminal 7 via a wire, and the external lead terminal 7 is connected to an external circuit. By doing so, the semiconductor element 6 is connected to an external circuit.

The external lead terminal 7 connects the insulating container 3 to the glass layers 5, 5.
It is attached between the insulating base 1 and the lid 2 at the same time when the parts a are melted and integrated and hermetically sealed.

Thus, according to this semiconductor element storage package, after the semiconductor element 6 is attached and fixed to the center of the upper surface of the insulating base 1 and each electrode of the semiconductor element 6 is connected to the external lead terminal 7 by a wire, the insulating base is The glass layers 5 and 5a, which have been previously attached to the glass layer 1 and the lid body 2, are heated and melted to integrate them, thereby airtightly sealing the semiconductor element 6 therein.

In the embodiment shown in FIG. 1 described above, a metal layer 8 made of gold (Au) is provided at the portion where the semiconductor element 6 is attached.
The metal layer 8 is formed by depositing a glass layer 5 on the main surface of the insulating base 1 by thick film printing, and forming external lead terminals 7 on the insulating base 1.
After melting and fixing the insulating substrate 1'' aluminum (
When provided on the metal layer 4 made of gold (Al), it is possible to effectively prevent the sealing glass from adhering to the gold metal layer 8 and reducing the bonding strength of the semiconductor element 6. The heat generated when the external lead terminals 7 are fixed to the base 1 causes the gold metal layer 8 and the underlying metal layer 4 made of aluminum to interdiffuse, forming an intermetallic compound and reducing the bonding strength of the semiconductor element 6. If a layer 8 made of gold for attaching and fixing the semiconductor element 6 is provided on the metal layer 4 provided on the insulating substrate 1, the metal layer 8 made of gold can be effectively prevented.
It is preferable to provide this after the external lead terminal 7 is attached and fixed on the insulating substrate l via the sealing glass layer 5.

Further, the thickness of the metal layer 4 made of aluminum in the present invention should be set to such an extent that the purpose can be fully achieved, for example, 0.1 to 10 μW, preferably 2 to 5 μW.
It is desirable to have a thickness of μm.

[Experiment example]

Next, the effects of the present invention will be explained based on experimental examples.

(Preparation of evaluation sample) A silicon carbide sintered body was produced by firing a molded body of silicon carbide powder to which 2.0% by weight of beryllium oxide was added at 2000°C, and this was washed to prepare an insulating base.

Next, aluminum is deposited on the surface of the substrate with various sealing areas by ion blasting, and then glass paste for sealing obtained by adding an appropriate solvent to low melting point glass powder is applied by screen printing using the conventional well-known method. It is deposited on the surface of an insulating substrate to a thickness of 0.3 mm using a thick film printing method such as the above, and then a pair of insulating substrates having the same sealing area are brought into contact with each other so that the glass paste surfaces for sealing face each other. At the same time, they are heated at a temperature of 460° C. to melt and integrate the sealing glass paste and join together.

(Evaluation method) A fixing jig is attached to each of the two substrates made of the silicon carbide sintered body of the above evaluation sample, and a torsion torque is applied to the evaluation sample via the jig, and a torsion torque is applied to the evaluation sample parallel to the torque application surface. The lowest torque value at which the specimen broke in the direction was measured, and this was evaluated as the adhesion strength between the base made of the silicon carbide sintered body, aluminum and the sealing glass.

The results are shown in Table 1.

Incidentally, sample numbers L6 and 11 indicate conventional examples.

Table 1 (blank below) As is clear from Table 1, sample number 1.6 does not have an aluminum metal layer on the base made of silicon carbide sintered body.
．． In No. 11 (conventional example), even if the sealing area is varied, the torque strength is low due to poor wettability and reactivity between the base and glass.

Therefore, the external lead terminals and the lid cannot be securely attached to the insulating base via the sealing glass, which is impractical.

In contrast, all of the products of the present invention had excellent wettability and reactivity between the insulating substrate and glass, and exhibited large torque strength.

Therefore, it can be seen that the external lead terminal and the lid can be securely attached to the insulating substrate via the sealing glass.

It should be noted that the present invention is not limited to the above embodiments and experimental examples, and it has been confirmed that similar results can be obtained even if other known silicon carbide sintered bodies are used as the insulating substrate.

〔Effect of the invention〕

As described in detail above, the glass-sealed semiconductor device storage package of the present invention has a metal layer made of aluminum deposited on the entire upper surface of the insulating base made of sintered silicon carbide. The adhesion between the glass layer and the sealing glass layer can be significantly improved. Therefore, the glass-sealed semiconductor device storage package of the present invention can securely attach external lead terminals, and can also hermetically encapsulate the semiconductor device inside, allowing it to operate normally and stably for a long period of time. can be done.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view showing an embodiment of a glass-sealed semiconductor element storage pancake of the present invention. 1... Insulating base 2... Lid body 4... Metal layer 5.5a... Glass layer 6... Semiconductor element 7... External lead terminal

Claims (1)

[Claims] A glass-sealed type in which an external lead terminal is sandwiched between an insulating base and a lid, which have a glass layer adhered to their opposing main surfaces, and the semiconductor element is hermetically sealed inside by melting and integrating the glass layer. In packages for storing semiconductor elements,
A glass-sealed package for housing a semiconductor element, characterized in that the insulating base is formed of a silicon carbide sintered body, and a metal layer made of aluminum (Al) is provided on the entire upper surface of the insulating base.