End-Point Detection for Polyimide Via Hole Etching in MCP Processing
Original Publication Date: 1985-Apr-01
Included in the Prior Art Database: 2005-Feb-18
This end-point detection procedure gives an unambiguous method to determine when the polyimide via holes have been etched to the chrome M-l metallurgy interface in the metallized ceramic polyimide (MCP) processing. During etching of C-cured polyimide on Cr/Cu/Cr metallurgy in an MCP structure in 6% CF4/O2 down-stream microwave plasma etcher, we have observed, visually and spectroscopically, a characteristic luminescence which appears above the sample and fills the chamber as the chrome interface becomes exposed. Monitoring this emission with a multichannel scanning diode array spectrometer between 400 nm and 800 nm just above the sample indicates that this luminescence represents a broad continuum that extends over the 400 nm band width of the observation.