METHOD FOR SEMICONDUCTOR SELECTIVE ETCHING AND BSI IMAGE SENSOR

摘要

A method of selectively etching a semiconductor device and manufacturing a BSI image sensor device includes etching a doped silicon substrate with an HNA solution for a predetermined time duration to obtain an etching solution having a concentration C1 of nitrite ions, etching the semiconductor device using the obtained etching solution. Etching the semiconductor device requires an initial concentration C0 of nitride ions that is lower than C1. The HNA solution comprises a hydrofluoric acid (HF), a nitric acid (HNO3), and a acetic acid (CH3COOH). The BSI image sensor device will have a uniform thickness when etched using the thus obtained etching solution.

主权项

1. A method of selectively etching a semiconductor device, the method comprising:
providing an etching solution having a first nitrite ion concentration C0; etching a doped silicon substrate with the etching solution for a predetermined time duration to increase the first nitrite ion concentration C0 to a second nitrite ion concentration C1; etching the semiconductor device using the etching solution having the second nitrite ion concentration C1; wherein the etching solution is an HNA solution comprises a hydrofluoric acid (HF), a nitric acid (HNO3), and a acetic acid (CH3COOH).