Investigation of systematical overlay errors limiting litho process performance of thick implant resists

Grandpierre, A.G.; Schiwon, R.; Bruch, Jens U.; Nacke, Christoph; Schroeder, Uwe

doi:10.1117/12.532334

Cited by 2 publications

(4 citation statements)

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Section: The Overlay Mark Optimizationmentioning

confidence: 99%

“…Previous studies tried to solve this issue from the process change perspective [1,2] . According to Yet [2] and Grandpierre [1] , in order to harden the film solidness, various bake settings are proposed. These settings typically involve changing the soft bake temperature or the post development bake conditions.…”

Section: The Overlay Mark Optimizationmentioning

confidence: 99%

“…In semiconductor manufacturing, a rather thick resist of 3 to 4 µm is commonly used for highenergy well implant layers (e.g., high voltage P wells, deep N wells, etc.). Typically, a poor uniformity for the overlay was observed [1,2] . Although there are some recent studies focusing on the CD-SEM metrology of the overlay residues [3] , the overlay tools in current foundries are mainly optical-based tools.…”

Section: Introductionmentioning

confidence: 99%

“…These are limited by the achievable optical resolution. There are also other papers addressing this metrology tool capability induced problem by optimizing the lithography process [1,2] . In this paper, instead of focusing on the process change methodology, we aim to solve this manufacturing issue from the overlay mark optimization perspective.…”

Section: Introductionmentioning

confidence: 99%

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Overlay mark optimization for thick-film resist overlay metrology

Zhu

Zhou

et al. 2009

J. Semicond.

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For thick resist implant layers, such as a high voltage P well and a deep N well, systematic and uncorrectable overlay residues brought about by the tapered resist profiles were found. It was found that the tapered profile is closely related to the pattern density. Potential solutions of the manufacturing problem include hardening the film solidness or balancing the exposure density. In this paper, instead of focusing on the process change methodology, we intend to solve the issue of the overlay metrology error from the perspective of the overlay mark design. Based on the comparison of the overlay performances between the proposed overlay mark and the original design, it is shown that the optimized overlay mark target achieves better performance in terms of profiles, dynamic precision, tool induced shift (TIS), and residues. Furthermore, five types of overlay marks with dummy bars are studied, and a recommendation for the overlay marks is given.

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