Improved scanner matching using Scanner Fleet Manager (SFM) Shian-Huan Cooper Chiua, Chin-Lung Leea, Sheng-Hsiung Yua, Kai-Lin Fua, Min-Hin Tunga, Po-Chih Chena; b Chao-Tien Huang , Chien-Chun Elsie Yub, Chin-Chou K. Huangc, John C. Robinson*c, David Tienc; a Rexchip Electronics Corp., No.429-1, Sanfong Rd.,Houli Township, Taichung County, Central Taiwan Science Park, Taiwan; b KLA-Tencor Taiwan, 1F, 22, TaiYuan Street, ChuPei City, HsinChu County 302, Taiwan ; c KLA-Tencor Corp., One Technology Drive, Milpitas, CA 95035;
ABSTRACT This project is the continuation of work reported previously at this conference (Yu, et. al., SPIE 2009). A new software tool for developing a static scanner fleet matching (SFM) matrix is tested including fleet snapshot and scanner pair drilldown. In addition the latest scanner models can adjust the distortion performance dynamically, at run-time, improving effective overlay performance of the scanner fleet, and allowing more flexibility for mix-and match exposure. The goal is to improve overlay |mean|+3s significantly between scanners for critical layer pairs. Keywords: scanner matching, overlay, metrology
1. INTRODUCTION Overlay performance has been a critical factor for advanced semiconductor manufacturing for many years. Over time these requirements become more stringent as design rules shrink. The transition to advanced nodes is requiring significant innovations such as the transition to high order control. A dominant component of the overlay error budget is a result of scanner matching errors, either machine to machine or illumination mode to illumination mode. For most critical layers, scanners are lot-to-lens dedicated, so no mix and match is allowed. For non-critical layers, however, mix and match enables better overall equipment effectiveness. Material can be routed to available machines, and multiple generations of scanners can be utilized. Current methods for fleet management are typically very time consuming. Manually checking scanner mix and match results by the golden tool method is the traditional mode. Once established, a monitor wafer is used to put a scanner back into production. For this process it is desirable to have a software tool to provide improved time to results and more powerful analysis capability. KLA-Tencor Corp. has developed a module in KT Analyzer© to provide Scanner Fleet Matching (SFM) capability. The goal is to allow the user to calculate distortion matching across the scanner fleet, and to calculate distortion fingerprints for specific combinations of scanner and illumination modes. The user can group matched scanners together based on the user’s spec. Scanners can be from different generations and from different vendors. The steps involved with the analysis are as follows, as shown in Figure 1. First it is necessary to plan out the mix and match scheme. Typically an existing fab scheme is utilized for this analysis. Second, it is necessary to create the PM, or preventative maintenance, lots per plan. Then it is necessary to measure the lots and approve them for use in this analysis. Finally, the data is available for the mix and match analysis. The analysis tool enables a flexible scanner and illumination condition snapshot for fleet matching, and in addition, the ability to look at scanner pair deltas or fingerprints.
Metrology, Inspection, and Process Control for Microlithography XXIV, edited by Christopher J. Raymond, Proc. of SPIE Vol. 7638, 76382A · © 2010 SPIE · CCC code: 0277-786X/10/$18 · doi: 10.1117/12.846667
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