Abstract: Removing a portion of an active wafer (12) at the edge (18) after the active wafer (12) is bonded to a base wafer (10) prevents chipping of the edge of the active wafer during thinning of the active wafer (12). Grinding and polishing of the edges of the active wafer (12) is preferably performed.

Abstract: A chemical sensor (10) is formed in part by depositing a stack of dielectric and resistive layers (13-15) on a support substrate (11). A cavity (17) is then formed on a substrate (16) to provide thermal isolation to the chemical sensor (10). The stack of dielectric and resistive layers (13-15) is then bonded to the substrate (16) and the support substrate (11) is removed. A layer of chemical sensing material (30) is then formed on the uppermost dielectric layer (15). Openings (33) may be formed through the stack of dielectric and resistive layers (13-15) to further enhance the thermal isolation of the chemical sensor (10) from the substrate (16).

Abstract: An apparatus and method for improved wafer bonding by scrubbing, spin drying, aligning, and pressing the polished wafers together. The first wafer (13) is mounted on a flat wafer chuck (11) and a second wafer (14) is mounted on a convex pressure gradient chuck (10). Wafers are scrubbed until a polished contamination free surface is obtained and pressed together. The convex pressure gradient chuck exerts a higher pressure at the center of the wafer than at the periphery of the wafer.