Method for fabricating electrically insulating layers

摘要

This invention relates to a method for fabricating a electrically insulating layer, more particularly, to the method for fabricating a electrically insulating layer by using the different etching rates in etching oxide and etching nitride. The present invention uses the way in different etching rates to etch oxide and nitride. When begin the etching process to fabricating the electrically insulating layer, the etching rate of oxide is higher than the etching rate of nitride. When the oxide layer contacts with the ending point which is situated between the oxide layer and the nitride layer or the nitride oxide layer, the etching rate of nitride is higher than the etching rate of oxide to form the flatter surface of the electrically insulating layer.