The main technical achievements of the project can be summarised as follows:
- An anodised aluminium insulated metal substrate has been developed with acceptable performance for many power electronics applications. The temperature robustness provided by this substrate and the low effective thermal resistance, together with the relatively low manufacturing costs provided are the major benefits. An improved electrical insulation performance would be desirable to open more high voltage applications, but this would require further research.
- Conductor processes compatible with the anodised aluminium substrate have been developed to enable the fabrication of practical circuits on its surface. A low temperature silver cermet provides the best available performance. While not as good as conventional printed circuit board copper conductors this technology is adequate for a large range of potential applications. Alternative conductor processes have also been developed to suit particular circumstances
- Applications demonstrators in the areas of power modules and automotive electronics have been fabricated and validated to prove the capabilities of the technology in industrial conditions.
The research covers a programme of work intended to lead to a novel mateirals and process technology for a high power electronic circuit substrate. This substrate is based on the use of aluminium, with an anodic coating to provide electrical isolation whilst still providing a good thermal conductivity. Novel techniques are used in the preparation of this coating, together with the introduction of a high integrity surface treatment to ensure environmental robustness.
The substrate resulting will be incorporated into three further areas of the research. Initially it will be incorporated into the power semiconductor packaging already developed by one of the proposers. Secondly this technology will be enhanced to allow the incorporation of conductor tracks on the substrate and hence the fabrication of complex multiple semiconductor packages. Finally the incorporation of thick film hybrid technology will allow the fabrication of complete power modules with the associated drive circuitry incorporated.
Two kinds of validation will be made :
- the first one, by bondig an existing flexible circuit on an anodized substrate to verify its compatibility with a components fitting process.
- the second one, on a specific power module to verify its ability with the automotive environment.
The OBJECTIVE of the work is a semiconductor packaging and hybrid circuit technology allowing very dense, low thermal resistance (less than 0.5 deg C/W) assemblies, both as individual and complex, "smart" packages, and its validation in industrial cases.
Funding SchemeCSC - Cost-sharing contracts
RG28 7BB Basingstoke