Engineering Tolerances & Performance in Applied EPD

For the past 10 years Cerel has been engaged in the development of prototype, EPDprocessed, micro-components, primarily for the microelectronics industry. In this contribution we summarize some of the problems of integrating EPD into the production process, and discuss the parameters that need to be considered and controlled. Suitable dispersion media and additives can usually be found for powder of any chemical composition to be deposited by EPD, providing the particle size and size distribution, and their surface to volume ratio are suitable. So it is the geometrical requirements and the dimensional tolerances of the product that often limit the EPD process. We give three examples: the EPD embedding of passive components in a punched ceramic tape, the production of porous capacitor anodes by EPD, and the EPD formation and printing of narrow conducting lines on a ceramic tape substrate. In each case the production process parameters have been chosen to satisfy the engineering requirements while minimizing the the formation of process defects. Defects include: variations in particle packing density; loss of adhesion and deposit cracking, and surface roughness or thickness variations.