New Alloy for Device Metal Masks/Or Silicon Masks
Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-04
The evaporation of metal materials onto silicon wafers to add terminal connections to integrated circuit and device chips is a high temperature process presently involving the use of a molybdenum mask. The mismatch in thermal expansion characteristics between silicon (wafer material) and molybdenum (mask material) requires compensation to be designed into the mask in order to achieve acceptable aperture (pad hole or terminal via) registration during the metal evaporation process (Figs. 1 and 2). Fig. 1 shows the mask and wafer as aligned at room temperature and (after metal evaporation), when ready to separate wafer from mask. Fig. 2 shows the relative positions of mask and wafer during the metal evaporation step (high temperature). Note (Fig.