METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for manufacturing a semiconductor device is to provide a high selectivity regarding a silicon substrate while easily etching a nitride layer and an oxide layer, by controlling a ratio of C and F as etching sources in forming a plurality of contact holes having different aspect ratios. CONSTITUTION: The oxide-based first insulating layer is formed on the first conductive layer. The conductive pattern having the nitride-based second insulating layer is formed on the first interlayer dielectric(2). The oxide-based third insulating layer is formed on the resultant structure. A mask pattern(6) for forming contact holes on the second conductive layer and the first conductive layer is formed. The insulating layers are etched until a predetermined thickness of the second insulating layer is exposed, by gas plasma of which a ratio of C/F is not less than 1/2. The insulating layers are etched until the second conductive layer is exposed after the second insulating layer is completely etched, by using gas plasma of which a ratio of C/F is not greater than 1/4. The insulating layers are etched until the first conductive layer is exposed, by using gas plasma of which a ration of C/F is not less than 1/2.