3-DIMENSIONAL PASSIVE CIRCUIT TECHNOLOGY FOR ULTRA-COMPACT MMICS

A novel passive circuit technology of a three-dimensional (3-D) metal- insulator structure is developed for ultra-compact MMIC's. By combinin g vertical passive elements, such as a wall like microwire for shieldi ng or coupling, and a pillar-like via connection with multilayer passi ve circuits, a 3-D passive circuit structure is formed to implement hi ghly dense and more functional MMIC's. O-2/He RIE for forming trenches and holes in a thick plyimide insulator, low-current electroplating f or foming gold metal sidewalls in the trenches or holes, and ion-milli ng with a WSiN stopper layer for patterning the gold metal are used to produce such a structure. The complete 3-D structure provides miniatu re microstrip lines effectively shielded with a vertical metal-wall, a miniature balun with low-loss vertical wall-like microwires, and inve rted microstrip lines jointed with pillar-like vias through a thick po lyimide layer. This technology stages next-generation ultra-compact MM IC's by producing various functional passive circuits in a very small area.