Mask defect printability in the spacer patterning process

摘要

We studied the mask defect printability for both opaque and clear defects in the spacer patterning process. The spacerpatterning process consists of the development of photoresist film, the etching of the core film using the photoresistpattern as the etching mask, the deposition of a spacer film on both sides of the core film pattern, and the removal of thecore film. The pattern pitch of the spacer film becomes half that of the photoresist. The opaque defect and the cleardefect of the mask, respectively, resulted in an "open-short complex" defect and a short defect in the spacer pattern, Thedefect size of both the opaque and clear defect became smaller as the process proceeded from the development to thecore film etching and the spacer pattern fabrication. The decrease of the mask defect printability during the spacerprocess is likely to be related to the reduction of the line width roughness (LWR) and to the reduction of mask enhancedfactor (MEF). The acceptable mask defect size was also studied from the viewpoint of the defect printability to thespacer pattern for both the opaque and clear defect, and found to be 55-60nm, which was relaxed from that in ITRS2007.