Particle free pellicle mounting inside of the large size photomask inspection system

摘要

While cleanness of Large Size Photomask (LSPM) is as important as that of LSI masks, the unit price of the pellicle for LSPM is much higher and pellicle removing from and remounting to LSPM is accompanied by troublesome tasks. Considering these facts, an automated pellicle inspection and mounting system that allows large size pellicle to be inspected and mounted onto a photomask automatically under a super clean condition is developed. The system size ranges from G6 to over G10. After picking up a pellicle from a carrier case, jigs remove liner sheet of the pellicle to allow stress free mounting of the pellicle on the LSPM using special chucks. Tow types of inspection heads are developed. One head has a sensitivity of 0.25 μm PSL with 150 seconds inspection time for 6 inch pellicle. Another head has a sensitivity of around 5 μm PSL with 20 minutes inspection time for size of G10. The jig can be flipped along with the Pellicle to allow inspection / blowing of the particles even on the inner side of the pellicle. Rejected pellicles are returned to the carrier case. The pellicle that passes a certain criteria is carried toward the Photomask Holder in the inspection system and mounted on the Photomask in the Holder.