US EPA

6687483 

Journal Article 

TDC model for PSG sacrificial layer etching with hydrofluoric acid 

Wu, C; Wang, H; Jin, Z; Ma, H; Wang, Y 

2008 

29 

6 

1094-1102 

INSPEC:10431630 

HF etching of sacrificial layers with different structures,namely channel,bubble,and joint-channel,is studied. The existing model cannot fit the experimental data well. The error of etching rate between the existing model and the experimental data increases with etching time. A modified model considering the diffusion coefficient as a function of HF concentration and temperature is proposed. The etching rate coefficient as a function of temperature and the effect of reaction production are also considered in the modified model. For the joint-channel structure,a new mathematical model for the etching profile is also adopted. Experimental data obtained with channel,bubble,and joint-channel structures are compared with the modified model and the previous model. The results show that the modified model matches the experiments well.