Nippon Steel Materials Starts 100-micron Level Bumping Service

Nippon Steel Materials announced on Friday the firm started commercial service to attach solder balls with less than 200 micrometers diameter on silicon wafer this summer which is used for wafer level chip size package (W-CSP) modules.Solder ball size for W-CSP module is mainly 300-350 micrometers diameter at present. Smaller solder balls realize smaller W-CSP modules. If solder ball size is halved to 100 micrometers diameter, length between solder ball bumps is halved and IC chip area becomes a quarter.Nippon Steel Material’s 100-micrometer level bumping service was already adopted into watches with global positioning system module and cellular phone with digital terrestrial broadcasting tuner module.Nippon Steel Materials has bumping lines to process 7,500 wafers per month in Oume plant of Casio Micronics, a subsidiary of Casio Computer. Nippon Steel Materials plans to expand the capacity to 20,000 wafers per month within 1-2 years.