Method for forming a hardmask employing multiple independently formed layers of a pecvd material to reduce pinholes

摘要

A bi-layer BARC/hardmask structure includes a layer of amorphous carbon and two or more distinct and independently formed layers of a PECVD material such as SiON formed on the amorphous carbon layer. By independently forming several layers of PECVD material, at least some pinholes that are present in the lowermost PECVD layer are closed by upper PECVD layers and therefore do not extend through all of the PECVD layers. As a result the upper surface of the uppermost PECVD layer has a lower pinhole density than the lower PECVD layer. This reduces photoresist poisoning by dopant in the amorphous carbon layer, and etching of the amorphous carbon layer by photoresist stripping chemistry.