Analysis of energy process window of laser metal pad cut link structure

Since laser metal cut processing has become a standard technology in the industry, the improvement of cutting metal lines has been an important issue. There has been extensive research focused on the optimization of metal cut structure as well as laser parameters. In this work, a metal pad cut link (or fuse) structure has been studied in comparison with a conventional metal linear cut structure through experimental observations and verified using three-dimensional finite-element modeling. The novel proposed structure improves the laser cut processing reliability. The finite-element analysis shows that the temperature in the aluminum line of the pad cut structure throughout the laser pulse duration is higher than that of the linear cut structure due to the reduced heat diffusion along the line. Consequently, the upper-corner cracking initiates faster and the lower-corner stress of pad structure develops faster at first, but starts to release right after earlier upper-corner cracking. This faster upper-corner cracking and delayed lower-corner cracking indicate a low chance for lower-corner cracking as well as possible low-power processing. Therefore, the pad cut structures have been shown to have a wider relative cut energy process window, which indicates higher reliability of laser processing and may result in higher density laser fuses.