Patent ID: 7892969
Filing Date: 2011-02-22
Classification: H01L

Abstract:
1. A method of manufacturing a semiconductor device, comprising: forming a first nitride layer over a substrate; forming a first oxide layer on the first nitride layer; forming a second nitride layer on the first oxide layer; forming a photoresist layer over the second nitride layer; forming an opening in the photoresist layer; etching the second nitride layer by using the photoresist layer as a mask such that the opening reaches the first oxide layer; etching the first oxide layer by using the second nitride layer as a mask such that the opening reaches the first nitride layer; etching the first oxide layer such that a bottom zone of the opening is increased in diameter; and etching the first nitride layer by using the first oxide layer as a mask such that the opening reaches the substrate thereby to form a contact hole reaching to the substrate; wherein a content rate of CF polymer in an etching gas used in the etching of the first oxide layer such that the bottom zone of the opening is increased in diameter is greater than a content rate of CF polymer in an etching gas used in the etching of the first oxide layer by using the second nitride layer as a mask such that the opening is reached to the first nitride layer.