Refractory Contact Stud
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Disclosed is a method of forming a planarized multilevel metal contact stud structure using refractory metals, such as W. A TiW-Al-W stud, in place of conventional TiW-Al stud prior to planarization, minimizes metal penetration which may occur at contacts. In the process, metals are sputter-deposited successively on the PtSi or Si chip contact 1 (Fig. 1). The sequence followed would be deposition of TiW 2, Al 3, W 4, and Al 5, upon which photoresist (PR) 6 would be applied. The PR serves as a mask for etching the top Al 5 layer. The Al 5 layer serves as a mask for etching the W 4 layer, while the Al 3 layer serves as an etching stop. A series of etching steps are undertaken to achieve the structure shown in Fig. 2, wherein W 4, Al 3, and TiW 2 are the metals remaining above the chip contact 1.