Microelectronic circuit structure including conductor bridges encapsulated in inorganic dielectric passivation layer

摘要

A gallium arsenide Monolithic-Microwave-Integrated-Circuit (MMIC) flip chip or other microelectronic circuit structure (10) includes a plated gold bridge (28) which serves as metal interconnect crossover between sites (24,-26) on a substrate (12). A first inorganic dielectric passivation layer (16), preferably of silicon dioxide, is formed under and supports the bridge (28). A second inorganic dielectric passivation layer (30), also preferably of silicon dioxide, is formed over and encapsulates the bridge (28) and the chip surface. A titanium/gold/titanium membrane (22) is formed under the bridge (28) to enable adhesion of the bridge (28) to the first passivation layer (16) and form plating contacts for the bridge (28). A contact bump post (38) is formed in a bump hole or via (32) which extends through the first and second passivation layers (16,30) to a bump contact site (34) on the substrate (12). Another titanium/gold/titanium membrane (40) is formed on the bump post (38) and the wall of the bump via (32) to provide a plating contact for a bump (42) which is plated on the membrane (40) inside the bump via (32) where the bump post (38) is located.