Manufacturing of Pt-electrode by wet etching

Increasing interest in bio-medical and analytical application of MST results in growing interest in patterning of platinum. A technique of platinum patterning was developed using sputtered Ti and CVD-deposited BPSG layers. A 600 °C heat treatment caused Ti and Pt migration. Resulted alloyed layer was removed in a standard H2SO4:H2O2 etchant. An influence of the heat treatment conditions on wet etching of the Ti-Pt alloyed layer was investigated. SIMS profiles, step measurement results and three-dimensional stress calculation were presented in the paper. Dependence of Pt-electrode features on Pt-sputtering conditions and on the type of the underlying insulator layer were discussed. Pt-electrodes on SiO2/Si3N4 dielectric layer were manufactured, suitably for ISFET application.