Direct Electroless Copper Plating on α-Almina Ceramics was investigated to obtain good adhesion. It was found that complicated etched micro pores created by immersion to high concentrated sodium hydroxide solution followed by heat treatment. These pores improved the mechanical bonding strength of the electroless copper to the α-Almina Ceramics. Adhesion strength of copper deposit was also increased by addition of alkyl amines, beryllium sulfate, selenium dioxide or vanadium pentaoxide. These additives promoted the microcrystallization of copper and improved anchoring effect between copper and ceramics.

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A hierarchical-fine-pattern router for high density PWB's carrying multi-pin SMD's (Hi-Fi Router) is described. A nonuniform grid for maze routing plays a key role to handle various kinds of design rules and pin pitches. A hierarchical method enables us to route complicated bundled nets in three steps: (1) global router, (2) detailed router, (3) design rule checking. This algorithm can easily be implemented in special-purpose hardware. Experimental results demonstrate that the hierarchical, nonuniform grid routing works successful for high density PWB's. The proposed algorithm reduces the number of grid points by a factor of 1/20 compared to conventional method, and it runs much faster than those router based on a uniform grid.

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