A NEW METHOD FOR MASS FABRICATION OF METALLIC MICROSTRUCTURES

This paper reports on a new method for the production of metallic micr ostructures with high aspect ratios that combines the advantages of in jection moulding with the high precision replication of surfaces by ga lvanic and electroless metal deposition. LIGA made moulding tools are used to produce plastic ''lost forms'', which are partially metallized by a silver cluster beam of high directionality to achieve electrical conductivity. For structures with an interconnected Ag layer at the b ottom, galvanic metal deposition is used to form massive microstructur es without voids. For isolated structures where contacting is not poss ible, chemical deposition was used for metal build-up starting from th e metallized areas. However, massive electroless deposition beyond abo ut 3 mu m was not yet possible due to problems with internal stress in the deposited metal layer that cause delamination from the template. This stress must be reduced by appropriate modifications of the electr olyte.