Redesigned Chuck Table: Deep-grooved Chuck Table for Higher Vacuum Suction of Singulated Package

Abstract

Singulation machine frequently encounters Z-Picker errors and occasionally, worst case of unit scattering which leads on the gross unit rejection and scrappage. As analyzed, shifted units found on the chuck table module upon singulation of strip. Shifted units were induced on the last 3 cut lines when the units were dragged by the blade as the area held by chuck table vacuum suction gets smaller. These shifted units caused misalignment on the next singulation modules to the turn table module and Z-Picker module that resulted to vacuum loss. With the situation at hand, the authors have assessed the current design of the chuck table. The authors have found out that chuck table have shallow-grooved rubber jig pockets that flatten upon suction of units resulted to lesser area for vacuum application. As referenced to the formula F=PA, larger area multiplied by suction pressure results to better force to hold the units, thus redesigned chuck table with deep groove was introduced. The study also pertains to the analysis and validation on the application of deep-grooved rubber jig pockets of chuck table aiming to solve the unit shifting during sawing. Elimination of unit shifting was validated to be effective upon application of the deep-grooved chuck table. The study and validation of redesigned chuck table is essential to avoid unit scattering and unit missing.