Portable Conformable Mask Patterning for Contact Hole Etching and Lift-Off of Contact Hole Stud
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
This article relates to a method of protecting exposed silicon at the bottom of a contact hole from reactive ion etch (RIE) metal level patterning with a metal contact stud. To effectively utilize the RIE technology to pattern metal films, exposed silicon at the bottom of a contact hole must be adequately protected. One technique used is to form a stud of material in a contact hole which is sufficiently thick to protect the silicon below from a RIE over-etch. A multilevel resist scheme combined with a metal lift-off process is used to form a metal stud in a contact hole. This approach is compatible with current tooling and does not require new metallurgical materials. At contact level photoresist, spin on two levels of photoresist, as shown in Fig. 1, instead of the usual one level.