Effects of wafer bow and warpage on performance of electrostatic chucks in high volume manufacturing

This paper presents learnings authors gained when dealing with back side pressure faults (BSPF) on 200mm interconnect deposition tools equipped with minimum contact area (MCA) electrostatic chucks (ESC). It was found that BSPFs occurred more likely on chucks running mostly BiCMOS product. BiCMOS product was four times more susceptible to experience this fault than CMOS due to higher wafer bow and warpage which were traced to recrystallization of backside polysilicon at RTP emitter anneal. Moreover, a cost-effective rework scheme was implemented to prolong the life of ESC's. Long term solution of reducing wafer bow and warpage process is also being pursued.