Patent ID: 6200735
Filing Date: 2001-03-13
Classification: H01L

Abstract:
A method for forming a contact hole, comprising:forming a hole opening in a first polysilicon film formed on an insulating film on a surface of a substrate;producing a second polysilicon film on an inner surface of said hole opening; anddry etching the insulating film to form the contact hole in the insulating film,a gas mixture consisting of C.sub.4 F.sub.8, O.sub.2, and Ar being used as an etching gas, and a mixing ratio of the Ar gas in the etching gas being set to 90 flow percent (%) or more,the dry etching resulting in formation of a polymer film on a side wall of the contact hole, the dry etching being carried out under a condition such that a concentration of C in the polymer film deposited on the side wall of the contact hole is 1.times.10.sup.15 cm.sup.-2 or less and an F/C concentration ratio in the polymer film on the side wall of the contact hole is 1 or more.