JPH04336453A - Semiconductor device - Google Patents

Abstract

PURPOSE:To protect a ceramic substrate against cracking by making a groove in the bottom face of the metal board of a semiconductor device, when a set of semiconductor device is assembled on a chassis, thereby protecting the ceramic substrate against driving stress of screw due to irregularities or foreign matter on the surface of the chassis. CONSTITUTION:A screw 5 is inserted into a fixing hole 3a of a metal board 3' in order to secure a semiconductor device to a chassis 4. A groove 6 is made in the bottom face of the metal board 3' between the end face of a ceramic substrate 1 mounted on the metal board 3' and the screw hole 3a. Consequently, even if irregularities or foreign matter exists on the surface of the chassis 4, driving force of screw is absorbed at the part which is made thin through the groove 6 thus suppressing the stress to be applied on the ceramic substrate as low as possible. Furthermore, since the groove 6 is made in the bottom face of the metal board 3', solder is prevented from flowing into the groove.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a semiconductor device in which a ceramic substrate is mounted on a metal plate.

0002

2 is a sectional view showing a conventional semiconductor device. In the figure, 1 is a ceramic substrate, 2 is a solder, and 3 is a sectional view showing a conventional semiconductor device.
is a metal plate, and 3a is a mounting hole. In such a semiconductor device, a ceramic substrate 1 and a metal plate 3 are bonded together by solder 2.

Next, the operation will be explained. As shown in FIG. 2, screws 5 are inserted into the mounting holes 3a of the metal plate 3, and the semiconductor device is fixed to the chassis 4 by the screws 5.

0004

[Problems to be Solved by the Invention] Conventional semiconductor devices are constructed as described above, so if the surface of the chassis is uneven or a foreign object is present between the back surface of the metal plate and the surface of the chassis, , stress is applied to the ceramic board due to the force of screwing, which may cause cracks in the board,
There were problems such as the board breaking.

[0005] This invention was made to solve the above-mentioned problems, and when a high-output semiconductor device is assembled on a chassis of a set, even if there are irregularities on the chassis surface or foreign objects are present, An object of the present invention is to obtain a semiconductor device that can prevent the occurrence of substrate cracking due to force applied to a ceramic substrate when screwing.

[0006]

[Means for Solving the Problems] A semiconductor device according to the present invention has a structure in which a groove is provided on the surface of the metal plate opposite to the ceramic substrate mounting portion between the end surface of the ceramic substrate and the screw tightening portion of the metal plate. It was designed to last.

[0007]

[Operation] In the semiconductor device according to the present invention, the grooves are formed in the metal plate from the bottom surface, so even if there are irregularities on the chassis surface or foreign objects, the force generated when screwing is absorbed by the grooves and the thickness is reduced. The stress on the ceramic substrate can be prevented as much as possible.

Furthermore, since the groove is provided on the lower surface of the metal plate, it is possible to prevent solder from flowing into the groove during soldering.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a semiconductor device according to an embodiment of the present invention. In the figure, 1 is a ceramic substrate, 2 is solder, and 3' is a metal plate according to the present invention, which is bonded on the metal plate 3'. It has a structure in which a groove 6 is provided from the lower surface of the metal plate 3' between the portion where the end surface of the ceramic substrate is located and the screw fixing portion 3a.

Next, the operation will be explained. As shown in FIG. 1, insert the screw 5 into the mounting hole 3a of the metal plate 3',
The semiconductor device is fixed to the chassis 4 by the screws 5. At this time, the groove 6 provided on the lower surface of the metal plate 3' connects the end surface of the ceramic substrate 1 on the metal plate 3' with the screw mounting hole 3.
Located between a.

As described above, according to this embodiment, since the groove 6 is provided on the lower surface of the metal plate 3' to which the substrate of the semiconductor device is bonded, when assembling this device on the chassis,
It is possible to prevent the force applied when screwing the screws from being applied as stress to the board due to irregularities on the surface of the chassis or the presence of foreign matter, and therefore cracks in the board can be prevented.

Furthermore, in this embodiment, since the groove is provided on the bottom surface, solder does not flow into the groove during soldering.

[0013]

As described above, according to the present invention, by providing a groove on the lower surface of a metal plate of a semiconductor device, when the device is assembled on a chassis of a set, unevenness on the surface of the chassis or the presence of foreign matter can be avoided. This makes it possible to prevent as much stress as possible from being applied to the ceramic substrate during screw tightening, which has the effect of improving measures to prevent cracks and splits in the substrate.

[Brief explanation of drawings]

FIG. 1 is a side view of a semiconductor device according to the present invention.

FIG. 2 is a side view of a conventional semiconductor device.

[Explanation of symbols]

1 Ceramic substrate 2 Solder 3 Metal plate 4 Chassis 5 Screw 6 Groove 3a Screw hole

Claims (1)

[Claims] 1. In a semiconductor device in which a ceramic substrate on which a semiconductor element and a circuit are formed is mounted on a metal plate by soldering, the metal plate is disposed between the end face of the ceramic substrate and the screwed portion of the metal plate. A semiconductor device characterized in that a groove is provided on the side opposite to the ceramic substrate mounting part.