摘要 |
A method of manufacturing a semiconductor device has 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 a opening in the photoresist layer, etching the second nitride layer using the photoresist layer as a mask such that the opening is reached to the first oxide layer, etching the first oxide layer using the second nitride layer as a mask such that the opening is reached to the first nitride layer, etching the first oxide layer such that bottom zone of the opening is increased in diameter, and etching the first nitride layer using the first oxide layer as a mask such that the opening is reached to the substrate thereby to form contact hole reaching to the substrate. |