Bright-Field AAPSM Conflict Detection and Correction

TL;DR

This paper introduces a new method for detecting and correcting phase conflicts in AAPSM layouts, improving efficiency and layout quality for advanced semiconductor manufacturing.

Contribution

It presents the first layout modification technique for bright-field AAPSM and a new conflict detection approach that enhances result quality and runtime.

Findings

Significant improvements in conflict detection quality and runtime.

Layout modifications increase area by 0.7-11.8%.

First application of layout correction results for bright-field AAPSM.

Abstract

As feature sizes shrink, it will be necessary to use AAPSM (Alternating-Aperture Phase Shift Masking) to image critical features, especially on the polysilicon layer. This imposes additional constraints on the layouts beyond traditional design rules. Of particular note is the requirement that all critical features be flanked by opposite-phase shifters, while the shifters obey minimum width and spacing requirements. A layout is called phase-assignable if it satisfies this requirement. If a layout is not phase-assignable, the phase conflicts have to removed to enable the use of AAPSM for the layout. Previous work has sought to detect a suitable set of phase Conflicts to be removed, as well as correct them. The contribution of this paper are the following: (1) a new approach to detect a minimal set of phase conflicts (also referred to as AAPSM conflicts), which when corrected will produce a phase-assignable layout; (2) a novel layout modification scheme for correcting these AAPSM conflicts. The proposed approach for conflict detection shows significant improvements in the quality of results and runtime for real industrial circuits, when compared to previous methods. To the best of our knowledge, this is the first time layout modification results are presented for bright-field AAPSM. Our experiments show that the percentage area increase for making a layout phase-assignable ranges from 0.7-11.8%.