JPH0319258Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to a hybrid integrated circuit in which circuits consisting of circuit components including power semiconductor elements that generate heat during operation are integrated. [Prior Art] Semiconductor devices are used in a wide range of applications from small signals to power fields, and the trend from individual devices to integration and modularization is expanding, and semiconductor devices are being used in automotive electronic equipment, consumer electronic equipment, and industrial electronic equipment. Hybrid integrated circuits have come into widespread use. Such hybrid integrated circuits are composed of materials with different coefficients of thermal expansion, such as structural metals, conductive metals, insulators, and semiconductors, and are mechanically strong and conductive. Alternatively, there are many locations where thermally conductive bonding is required. 2 and 3 show an example of a hybrid integrated circuit, and FIG. 5 is a sectional view of the bonded portion. A metal support 2 made of an iron plate is fixed on the bottom surface of an aluminum container 1 shown in FIG. A control section formed by attaching circuit components (not shown) to a membrane printed circuit is provided. The surface of the ceramic plate 3 is usually metallized in order to be bonded with solder. 11 is a metallized layer of the ceramic plate 3. The terminals of the control section and the transistors are connected by lead wires 6. In this case, the constituent materials have decreasing coefficients of thermal expansion in the order of aluminum, iron, ceramics, and semiconductors. [Problem to be solved by the invention] However, when such members with different coefficients of thermal expansion are bonded together using a brazing material, adhesive, etc., the difference in coefficients of expansion causes warpage due to the bimetallic effect, and the alumina plate Such members that are weak against bending will be damaged. Even if there is no damage, the brazing material or adhesive may peel off from the component due to expansion or contraction due to heat generation or cooling during operation, especially in power devices, or fatigue fracture may occur in the intermediate layer between the brazing material and adhesive resin. , electrical resistance, and thermal resistance increase, causing thermal destruction of individual functional elements. As a countermeasure against this, for example, a method is used between the container 1 and the support body 2 shown in the figure, and as shown in the section taken along the line A-A in FIG. It has been known. However, in this method, the number of parts increases, and since both contact surfaces must have good smoothness and be in planar contact, the number of processing steps also increases. Therefore, it is desirable to be able to achieve highly reliable bonding by brazing or adhesion, which can be applied to commonly processed surfaces. Another possibility is to thicken the brazing material or adhesive that bonds the parts together to alleviate the stress caused by the difference in thermal expansion. The inclination causes problems such as making it impossible to bond lead wires to the semiconductor elements on the upper member. Therefore, an object of the present invention is to provide a hybrid integrated circuit in which members having different coefficients of thermal expansion are connected with high reliability by brazing or adhesion. [Means for Solving the Problems] The present invention provides a hybrid integrated circuit in which, among members having different coefficients of thermal expansion that are thermally connected by brazing or adhesion, the member with a larger coefficient of thermal expansion is opposed to the member with a smaller one. It is characterized in that a plurality of grooves are provided in the portion of the surface to be brazed or bonded, and the portions including the grooves are also brazed or bonded. [Function] As described above, the present invention provides a plurality of grooves to braze or bond members with different coefficients of thermal expansion without changing the apparent thickness of the solder or adhesive, that is, the spacing between the members. The increased amount of solder or adhesive increases the elastic deformation of these solders or adhesives, allowing them to act as a buffer, absorbing and relieving stress caused by differential thermal expansion between components. [Example] The present invention will be described below based on an example. FIG. 1 is a sectional view of a bonded portion showing an embodiment of the present invention. In FIG. 1, a V-shaped groove 9 having a depth of 300 μm and a width of 150 μm, for example, is formed on the surface of a 0.1 mm thick support 2 made of iron, which is fixed to an aluminum container 1 of a hybrid integrated circuit by, for example, a pressure contact method. of
They are formed at intervals of 50 μm, and an alumina plate 3 having a thickness of 0.635 mm is bonded onto the surface using solder or adhesive 10. As a comparative experiment, a steel plate with grooves and a steel plate without grooves were brazed to an alumina plate with a solder having a melting point of 183°C with a eutectic composition and a thickness of 50 to 100 μm was subjected to a sudden temperature change. It was investigated whether or not cracks would occur in the board. The transition time to each temperature was within 5 seconds, and Table 1 shows the results.The denominator of the failure rate is the number of samples, and the numerator is the number of cracks.

[Effect of idea]

As mentioned above, the present invention solves the problem of temperature rise due to heat generation of power elements constituting a hybrid integrated circuit.
By providing grooves on the surface of the member with a larger coefficient of thermal expansion, the repetitive stress that occurs in the bond between members with different coefficients of thermal expansion due to lowering is alleviated without reducing the heat dissipation effect, thereby preventing deformation or damage of the member. This has an extremely large effect on improving the reliability of hybrid integrated circuits.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an adhesive part showing an embodiment of the present invention, FIG. 2 is a plan view of an example of a hybrid integrated circuit excluding the container, FIG. 3 is a cross-sectional view including the container, and FIG. FIG. 2 is a cross-sectional view taken along the line A-A, and FIG. 5 is a cross-sectional view of a conventional adhesive portion. 2... Metal support, 3, 5... Ceramic plate,
4...transistor chip, 9...groove, 10...
solder (or glue).

Claims (1)

[Scope of utility model registration request] Among members having different coefficients of thermal expansion that are thermally conductively coupled by brazing or gluing, a plurality of grooves are provided in the part to be brazed or bonded on the surface of the member with a larger coefficient of thermal expansion that faces the smaller member; A hybrid integrated circuit characterized in that the groove portion is also brazed or bonded.