AFTER-CORROSION SUPPRESSION USING LOW-TEMPERATURE AL-SI-CU ETCHING

The authors investigated the low-temperature etching effect on Al-Si-Cu after-corrosion. The after-corrosion extent was evaluated from the corrosion point density generated on the rinsed Al-Si-Cu stripes after dry etching. As the etching temperature was reduced, after-corrosion was suppressed. In order to study the low-temperature etching effect, the authors analyzed the Cl compounds remaining on the Al-Si-Cu film by thermal desorption spectroscopy (TDS). TDS revealed that the Cl concentration remaining on the Al-Si-Cu film etched at -60-degrees-C after rinsing in water was smaller than that remaining on the film etched at 30-degrees-C. Consequently, suppression of after-corrosion by low temperature etching could be attributed to the smaller number of Al-Cu bonds remaining in the Al-Si-Cu etch surface after removal of the AlCl(x) layer by rinsing with water. This fact is due to the reduction of chemical reaction and diffusion rate by lowering the substrate temperature.