Bonding head design for thin wafer

In this paper, porous vacuum picker and bonding head to impose uniform pressure on all the surface of wafer in the bonding process are proposed newly. Porous vacuum picker could reduce deformation and warpage problem during handling thin wafer because it has many number of small vacuum hole which induce small vacuum pressure at those holes region. Also, to impose uniform pressure on the wafer under bonding process, bonding head is designed using air piston type with metal ball joint, which automatically compensate for coplanarity problem of bonding pad. FEM analysis and experiments are conducted to evaluate the performance of porous vacuum picker and bonding head of air piston type.