Semiconductor device with monocrystalline silicon substrate - has chamfered conductor paths to improve hermetic passivation

摘要

At least one side of the substrate (1) possesses several zones(2,3,4) formed by diffusion, and then covered with a passivating layer(5) of SiO2, in which windows(6) are etched. Layer(5) is then covered by a first metallising layer(7) of Al which enters the windows(6), and then a second Al layer(8), which has a faster etching rate than layer(7). A single etchant is then used to form contact terminals and conductor paths from layers(7,8). Layer(7) is pref. pure Al, or an Al-Cu alloy; whereas layer(8) is pref. Al-Ni contg. 0.5-1% Ni, the amt. of Ni being altered to adjust the etching speed; layer(8) is thinner than layer(7). The etchant for layers(7,8) is pref. H3PO4 used at 30-60 degrees C. Layer(8) results in chamfered edges on the contact terminals and conductor paths formed in layer(7) so the protective, hermetic seal is improved.