Such press-pack semiconductor devices may be used in high-power converter applications such as high-current rectifiers or medium-voltage drives. In these systems, fault situations may occur in which a device loses its blocking capability and may be subject to an excessive fault current in the reverse direction. The local heating caused by this fault current may lead to electric arcing inside the device. The high temperature of the electric arc (˜20,000° C.) and the resulting pressure increase may cause damage to the hermetically sealed press-pack housings.
If the energy released in the arc is sufficiently high, the arc plasma may burn through thin metal flanges of the housing, or may crack a ceramics insulating ring of the housing, which surrounds a Si wafer. Fast-enough fuses may be used to protect the semiconductor device. Also, a housing design that will not rupture under the expected short-circuit current integral may provide further protection.
To prevent the impact of the arc plasma on the flanges and ceramics ring and thereby improve the non-rupture capabilities of a press-pack semiconductor device, a protective ring-shaped part made of polymer material may be arranged in the volume between the ceramics ring and the Si wafer.
DE 103 06 767 A1 relates to a press-pack semiconductor device with a housing isolator, interposed between two electrodes. Inside the housing isolator, a further isolator surrounds a semiconductor element.
DE 89 09 244 U1 shows a press-pack semiconductor device having a ceramics ring as part of a housing. Inside the ceramics ring a Teflon band may be arranged.
DE 30 32 133 C2 shows a press-pack semiconductor device with a cylinder element of ceramics surrounding an explosion protection element of silicone, in which the semiconductor is arranged.
In EP 2447988 A1 a semiconductor device is disclosed, that comprises two electrodes with opposite faces, a semiconductor wafer sandwiched between the two electrodes, an outer insulating ring attached to the two electrodes and surrounding the semiconductor wafer, a middle insulating ring inside the outer insulating ring and surrounding the semiconductor wafer, whereby the middle insulating ring is made of a plastics material, and an inner insulating ring inside the middle insulating ring, whereby the inner insulating ring is made of ceramics and/or glass material. A very similar semiconductor device is shown in JP H04114474 A.
Moreover, DE 19710207 A1 discloses a well-known and generic housing of a power electronic element.