Hi Is anyone can help me figureout this question. Here is my structure: Poly5K+P-dope (-100Mpa) ------------ PSG6.0um (-90Mpa) ------------ Poly10K+ P-dope(-150Mpa) ------------ PSG2.0um (-90Mpa) ----------- Si wafer Why the bubbles showsup after Poly5K+P-dope . And the wafer has serious bending. If I change PSG6.0um stress,The film of Poly5K cracked too. I have tried anneal after PSG6.0um deposition, but still no work