| abstract |
An altered layer and a strained layer are removed without adding a mask layer forming step after forming a laser processing groove and before dividing a semiconductor wafer. Forming a laser processing groove by partially removing a semiconductor wafer, a protective layer and a functional layer to expose the semiconductor wafer; Covering a region excluding the region with a mask layer, performing a plasma etching using a first gas on the protective layer through the mask layer to expose a metal electrode, and a first etching A second etching step of expanding the laser processing groove by performing plasma etching using the second gas on the laser processing groove via the mask layer after the step, and a laser processing groove expanded in the second etching step And a dividing step of dividing the semiconductor wafer into device chips along the semiconductor device. [Selection diagram] FIG. |