Stress Measurement Device
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
In the fabrication of integrated circuits, multilayer structures of metals and oxides are deposited onto semiconductor substrates. Stresses can occur in these structures due to lattice misfit and/or by differences in thermal expansion. These stresses cause the wafer to deform; for example, if a film of silicon nitride is deposited by chemical vapor deposition onto a flat silicon substrate, the substrate film combination will deform to the shape of a segment of a sphere, as shown in Fig. 1. This indicates that the film is under tension. The radius of curvature of the film/substrate is inversely proportional to the stress of the film.