Relieving the Effects of Stressed Thin Films
Original Publication Date: 1985-Jan-01
Included in the Prior Art Database: 2005-Feb-18
Mechanical stress in metal thin film layers causes shearing forces between the thin film and the overlying passivation layer. Such mechanical stress results in cracking of the less elastic passivation layer. The mechanical stress build-up in the thin film is substantially reduced by forming an oblique edge at the thin film ends above the passivation layer. The oblique edge is obtained by offsetting the evaporation source and moving the source during the evaporation process. As indicated in Fig. 1, the chromium source (Cr) source is located at position 1, the copper (Cu) source is located at position 3, and the gold (Au) source is located at position 4. The distance between the Cr source and the Cu source is increased over the distance heretofore used. As the evaporation process begins, Cr evaporation begins at position 1.