METHOD FOR COMPENSATING METAL BASE LAYER UNDERCUT AND WLCSP MANUFACTURING METHOD USING THE SAME

摘要

A method for compensating for an undercut of a metal base layer is provided to guarantee the area of a metal base layer by compensating for an undercut of a metal base layer under a redistribution layer or a solder bump. An insulation layer is formed on a semiconductor wafer(91). The insulation layer is covered with a multilayered metal base layer(92). A photomask having an open part is formed on the metal base layer(93). The photomask is dry-etched to form a concave part that rounds toward the inner lower part of the inner wall of the open part adjacent to the metal base layer(94). The open part including the concave part is filled with a plating layer(95). The photomask is eliminated(96). The metal base layer outside the plating layer is wet-etched(97). The metal base layer that is etched toward the inside of the outer surface of the plating layer on the upper part of a protrusion part is reduced by the protrusion part of the plating layer filled in the concave part so that an area of the metal base layer under the plating layer is guaranteed. The plating layer can be a redistribution layer or a solder plating layer for a solder bump.