Patterning Platinum by Selective Wet Etching of Sacrificial Pt-Al Alloy

Regardless of its functionality, there is no IC-compatible process to pattern platinum. This can be attributed to the inertness of the noble metal. Pt survives extreme condi-tions, and is used in electrochemical, temperature, and gas sensors. In this paper, we introduce a process enabling Pt structures of 1μm thickness and submicron feature size on 200mm wafers. It is the industry’s first with focus on high process control while eliminating contamination is-sues. This is achieved by locally alloying the Pt with a sacri-ficial Al layer. The so-formed PtAl2 is then removed by a selective wet-etch, which leaves a uniform Pt structure. The process is VLSI compatible, and can be adapted to any semi-conductor fab to have a platinum processing capability. Pt as a third metal besides Al and Cu is a significant enabler for IC sensor technology     «

Regardless of its functionality, there is no IC-compatible process to pattern platinum. This can be attributed to the inertness of the noble metal. Pt survives extreme condi-tions, and is used in electrochemical, temperature, and gas sensors. In this paper, we introduce a process enabling Pt structures of 1μm thickness and submicron feature size on 200mm wafers. It is the industry’s first with focus on high process control while eliminating contamination i...     »