DE3318729A1 - Structure for electrically insulating a semiconductor component - Google Patents

Abstract

In this structure for making potential-free thermal contact to a semiconductor component (1), in particular a power thyristor or a power diode, using a heat sink (5, 9), a laminate (4, 8) is provided as electrical insulating layer. The laminate (4, 8) is composed of an aluminium oxide fibre braiding impregnated with an adhesive, preferably an adhesive containing 60 % aluminium oxide filler in powdered form. The laminate (4, 8) combines high electrical insulating capacity with good thermal and mechanical properties. In particular, it is very resistant to pressure and permits high contact forces between semiconductor component (1) and heat sink (5, 9) in order to produce a good electrical contact between metal terminal plates (2, 6) of the semiconductor component (1) and conductor rails (3, 7) used for interconnection. <IMAGE>

Description

Arrangement for the electrical isolation of a

Semiconductor component The invention relates to an arrangement for the electrical insulation of a semiconductor component according to the preamble of Claim 1.

Such an arrangement for the electrical insulation of a semiconductor component is known from DE-OS 10 25 9h4.

In the known case, there are between the semiconductor component and the cooling body a polvetrafluoroethylene layer or an insulating varnish layer, e.g. a Silicone padding varnish layer, arranged. These insulation layers exhibit good electrical insulation and enable a good thermal heat transfer. When using power semiconductor cells with high SDers voltage and high power however, the thermal conductivity of the thicker insulation layers required is sufficient no longer everything to ensure rapid heat transfer in the power semiconductor cell arose to ensure heat loss to the heat sink.

On this basis, the invention is based on the object of providing an arrangement for the electrical insulation of a half-parent component of the type mentioned at the beginning specify which, especially when using power semiconductor cells, a Satisfactory heat transport guaranteed.

This object is characterized by the features in claim 1 marked solved.

In this context, it is generally known a ceramic plate to be provided as an insulation component between a semiconductor component and a heat sink. Such ceramic plates hold the required for power half-liter cells high pressure forces, however, did not stand, which resulted in fine cracks in the ceramic and in extreme cases leads to breakage. This increases the dielectric strength, resulting in electrical breakdowns.

The advantages that can be achieved with the invention are, in particular, that the proposed insulation layer is inexpensive to manufacture and easy to manufacture is foul and intensive cooling of the semiconductor component at the same time good electrical insulation guaranteed.

Further advantages can be seen from the following description, Advantageous embodiments of the invention are characterized in the subclaims.

The invention is explained below with reference to the in the drawing shown Embodiment explained.

The drawing shows a semiconductor component (power semiconductor cell) 1 in disc cell design with a ceramic housing, for example a Lelstungsdiode or a power transistor shown that be one at its one end face first metallic connection plate 2, for example the anode connection, with a first copper busbar 3 is contacted. The connection plate 2 is used at the same time for the transfer of electricity and heat. The first busbar 3 is used for electrical Connection of the semiconductor component 1 to further semiconductor components, not shown a converter circuit or for connection to a main terminal.

The semiconductor component 1 is via the busbar 3 and a first Insulation layer (laminate) 4 with a first metallic heat sink 5 thermally contacted.

With a symmetrical structure on both sides of the semiconductor component 1 is a second metallic connection plate 6 on the further end face of the semiconductor component 1, for example the cathode connection, with a second copper busbar 7 contacted. This second busbar 7 is used, for example, for electrical connection of the semiconductor component 1 with a further main terminal. The busbar 7 is Via a second insulation layer (laminate) 8 with a second metallic cooling body 9 thermally contacted.

The two heat sinks 5 and 9 can be electrically conductive with one another be connected.

The insulation layers 4, 8 consist of a laminate of aluminum oxide fibers (Al2O3), which are soaked with an adhesive. The aluminum oxide fibers are preferably woven in the form of a mesh (mat). A polvmid glue is suitable as an adhesive or an inorganic shear adhesive that contains more than 60% alumina filler in powder form having. However, there are other well known electrically insulating organic ones as well or inorganic adhesives are suitable.

The result is an insulation layer reinforced with Al209 fibers 4.8 with very high electrical insulation properties, with excellent thermal Properties and with very good mechanical properties.

The very high electrical insulation capacity is due to the good insulating properties of the aluminum oxide ceramic and the adhesive. The excellent thermal properties (low thermal resistance) result from the high proportion. to aluminum oxide ceramic (Al2O3 fibers, Al203 powder have together over 70% volume fraction in the laminate) in the insulation layer 4. Furthermore, the Insulation layers 4, 8 still with the busbars 3, 6 and the heat sinks 5, 9 with the help of the adhesive described be firmly glued to thermal ffberganaswidergtande to exclude. The very good mechanical properties, especially the high one Compressive strength, are ultimately due to the laminate construction and the Elastizi.tSt of the adhesive justified.

The high compressive strength of the insulation layers 4, 8 is necessary to high contact pressure between the semiconductor component 1 and the heat sinks 9, 9 to enable. This creates a good electrical contact between the metallic Connection plates 2, 6 of the semiconductor component 1 and the busbars 9, 7 achieved.

The pressing forces are with the help of a clamping device, not shown upset.

In addition to the described symmetrical clamping of the Semiconductor component 1 between two heat sinks 5, 9 is also only one of the components 1 to 5 existing arrangement can be executed, in which case the second electrical connection of the Semiconductor component 1 is designed, for example, as a screw or plug connection.

The arrangement described offers the possibility of forming Converter devices a plurality of semiconductor components 1 to one or more Kilhlköreer 5, 9 to be mounted insulated. Since the heat sinks are each potential-free they can also be attached outside of control cabinets, thus simplifying the process can be achieved in cooling and in cabinet construction.

Claims (1)

Claims 1. Arrangement for electrical insulation of a semiconductor element on a heat sink by means of an insulation layer, characterized in that that between the heat sink (5.9) and the electrical connection of the semiconductor component (1) one made of alumina fibers and an electrically insulating adhesive Laminate (4,8) is arranged. ?. Arrangement according to Ansoruch 1, characterized in that the aluminum oxide fibers in the case of the laminate (4.85 in the form of a woven mesh. 3. Arrangement according to one of the preceding claims, characterized in that that a polvmid adhesive can be used as an adhesive. 4. Arrangement according to one of the preceding claims, characterized in that that the adhesive is an inorganic adhesive with a content of at least 60% Al2O3 ceramic powder can be used. 5. Arrangement according to one of the preceding claims, characterized in that that laminate (4.8), cooling grains 5.9) and electrical connection of the semiconductor structure] e ments (1) are each glued together.