Partially-Supported Bridge Structure
Original Publication Date: 1988-Sep-01
Included in the Prior Art Database: 2005-Feb-15
A partially-supported bridge structure is proposed for circuit wiring. It provides low parasitic capacity connections and is thus well suited for use in high-speed integrated circuits. Fig. 1(a) shows the starting point of the process for the fabrication of the final T-structure that is formed by the metal wire and the smaller-width support. Deposited on a substrate 1 are an insulator layer 2 (e.g., polyimide) and, on top of it, a patterned wiring metallization 3 (e.g. Ti/Au). The insulator is then reactive ion-etched (RIE) with oxygen in two steps: a first, anisotropic low pressure RIE process results in vertical insulator walls (Fig. 1(b)), and the following higher pressure isotropic RIE process provides the undercut and thus the final T-structure (Fig. 1(c).