Patent ID: 9646848
Date: 2017-05-09
CPC Classifications: H01L

Claim:
1. A method for etching a silicon oxide film on a target substrate where an etching area is partitioned by a pattern layer and stopping the etching before a base layer of the silicon oxide film is exposed, the method comprising: heating the target substrate in a vacuum atmosphere; starting a supply of an ammonia gas to the silicon oxide film for ammonia molecules to be adsorbed onto a surface of the silicon oxide film; starting a supply of a hydrogen fluoride gas at a lapse of a first time period after said starting of the supply of the ammonia gas, thereby supplying a gaseous mixture of the ammonia gas and the hydrogen fluoride gas to the silicon oxide film during a second time period; and stopping said supply of the ammonia gas and said supply of the hydrogen fluoride gas at the same time, thereby stopping said supplying the gaseous mixture during a third time period, wherein said starting the supply of the ammonia gas, said supplying the gaseous mixture and said stopping supplying the gaseous mixture are repeated multiple times, and wherein the first time period is about 0.5 sec to 15 sec of said supply of the ammonia gas.