A study of sub-atmospheric chemical vapor deposition (SACVD) O3-TEOS UGS, BPSG, PSG, and plasma enhanced chemical vapor deposition (PECVD) PSG film as sacrificial layers in a micro-fluid dispenser device

In this paper, we investigated SACVD O3-TEOS USG, BPSG, PSG and PECVD PSG films as sacrificial layers to formation a fluid tank with a fluid barrier layer in a micro-fluid dispenser device. The wet etch rate of as deposited films was measured and the SACVD PSG film performed with the highest wet etch rate as 5913A/min in a 6:1 buffered oxide etch solution. Inversely, the SACVD BPSG film displayed a lowest wet etch rate as 1650A/min in comparison with other sacrificial materials above. In the process integration consideration, patterned wafer with stacking sacrificial layers and fluid barrier layers were fabricated, then the sacrificial layer etched out in HF solution. Based on the microscopic view the SACVD PSG film again displayed a fast removal. However, the SAC VD BPSG film that shown a better removal rate than the PECVD PSG film is different with the deposited film characteristic. From a series of analysis by FT-IR instrument, the control wafer deposited with different sacrificial films above, then processed with the rapid thermal anneal or furnace anneal process showed that the boron (B) content decrease after thermal anneal was the dominator for the wet etch property performed.