a packaged semiconductor device containing no ubm between a chip pad and an rdl pattern is described . as well , the device contains only a single non - polymeric insulation layer between the rdl pattern and the solder bump . the single non - polymeric insulation layer does not need high temperature curing processes and so does not induce thermal stresses into the device . as well , manufacturing costs are diminished by eliminating the ubm between the chip pad and the rdl pattern .