Verification of Open Contacts in SiO(2) Layers
Original Publication Date: 1980-May-01
Included in the Prior Art Database: 2005-Feb-13
Contact resistance of metal to silicon is difficult to control. It is possible to identify open or closed holes to the limit of horizontal optical resolution through suitable additives to the etching solution. During the etching step, the additive is non-reactive. However, upon exposure of silicon at the bottom of the contact, the additive reacts with the silicon to form a thin coating of different optical appearance for verification of open contacts. After completion of the etching, the coating can be removed by chemical means.