Interconnection structure fabrication method for semiconductor device, involves etching portion of etch stop layer and sacrificial insulating layer such that thickness ratio of layers is set to specific value

摘要

A sacrificial insulating layer (130) is formed on an intermetal insulating layer (120) on a substrate (100). A photoresist pattern (140) is formed on layer (130) to define a trench formation region. The layer (120) is etched using photoresist pattern as mask, to form a trench and to expose portion of etch-stop layer (110). The layers (110,130) are etched so that thickness ratio is in an inclusive range of 2:1 through 1:1.