Low Temperature Process for Patterning Copper Films Using Resist Masks
Original Publication Date: 1985-Aug-01
Included in the Prior Art Database: 2005-Feb-19
An invention has been made to dry etch copper using a halocarbon gas plus an inert gas. The method makes it possible to utilize regular photoresist processing as well as permitting etching to be performed on an unheated cathode. Existing processes use carbon tetrachloride (CCl4), an inorganic mask, and operate at high temperature (300ŒC). Furthermore, inorganic masks are required which considerably increase the process steps and complicate the overall process. The CCl4 process has several drawbacks. Formation of polymers on the wall and ceiling of the system contributes to non-uniformity and prevents repeatability of etch rates from run to run. Since elevated temperatures are required, normal room temperature photoresist patterning is impossible and inorganic masks have to be deposited and eventually removed.