METHOD OF IMPROVING VISCOSITY OF PHOTORESIST

摘要

PURPOSE: A method is provided to improve the step coverage and viscosity of photoresist by adding pre-pattern ashing before coating the photoresist. CONSTITUTION: The first insulating layer(21), an etch stop layer(22) and the second insulating layer(23) are sequentially formed on a silicon substrate(20). A trench is formed by removing selectively the second insulating layer using the first photo process. Pre-pattern ashing is performed on the resultant structure by using O2 plasma, CxFx based gas or Ar gas. A contact hole for exposing partially the silicon substrate is formed under the trench by removing selectively the first insulating layer using the second photo process. A dual damascene pattern made of the trench and the contact hole is filled with metal.