Yung-Sung Yen

Layout patterning check for DFM

Design rules and the design rule check (DRC) utility are conventional approaches to design for manufacturability (DFM). The DRC utility is based on unsophisticated rules to check the design layout in a simple environment. As the design dimension shrinks drastically, the introduction of a more powerful DFM utility with model-based layout patterning check (LPC) becomes mandatory for designers to filter process weak-points before taping out layouts. In this paper, a system of integrated hotspot scores consisting of three lithography sensitive indexes is proposed to assist designers to circumvent risky layout patterns in lithography. With the hotspot fixing guideline and the hotspot severity classification deduced from the scoring system provided in this paper, designers can deliver much more manufacturable designs.

Global CD uniformity improvement in mask manufacturing for advanced lithography

The control of global critical dimension uniformity (GCDU) across the entire mask becomes an important factor for the high-end masks quality. Three major proceses induce GCDU error before after-developing inspection (ADI) including the E-Beam writing, baking, and developing processes. Due to the charging effect, the fogging effect, the vacuum effect and other not-well-known effects, the E-Beam writing process suffers from some consistent GCDU errors. Specifically, the chemical amplified resist (CAR) induces the GCDU error from improper baking. This phenomenon becomes worse with negative CARs. The developing process is also a source of the GCDU error usually appears radially. This paper reports the results of the study of the impact of the global CD uniformity on mask to wafer images. It also proposes solutions to achieve better masks.