Sonoscan has started shipping its 300 mm bonded wafer inspection system that is automated and capable of scanning two wafers at the same time. The users are benefitted by the double throughput output from the inspection system.
The system conducts a thorough inspection of the wafer pairs, which are used in SOI, MEMS and other applications. The wafers that are inspected by the system are 300 mm and 200 mm wafers, which are virtually bonded by any technique. The defects that are checked by the system are disbonds, voids, delaminations, cracks of any depth and particles present at the bond interface.
The AW300TM is an inspection system, which is based on the C-SAM acoustic microscope systems from Sonoscan. The AW300TM automates the complete inspection system right from attaching the carrier and selecting the wafer to drying, sorting and acoustic imaging. The wafers are loaded onto two ports, which are compatible with FOUP or FSOB carriers by the robotic arm. The wafers are fed into one of the two scanners. In order to ensure a maximum output, the wafers are arrayed in a staging area where they are processed and amassed provisionally. The inspection system uses transducers from Sonoscan that have a frequency range of 100 to 400 MHz. The ultra-high frequency transducers from Sonoscan are matched, manufactured and designed internally in order to achieve the most favourable performance.
The inspection system, AW300, has the capability of detecting voids in inter-wafers, which are as small as 5 µ and very thin delaminations in the order of 100A. For scanning the wafers, the inspection system uses WaterfallTM transducers that non immersive and some of the stages are vacuum assisted. The software measures the bonded and the unbounded interfaces between the two wafers and the number and sizes of the voids. The decision to reject or accept a wafer is taken automatically as per the specific criteria of the user.