Paper
24 May 2004 Optimization method of edge shot yield for various wafer layouts
Anna Eidelman, Avi Blau, Irit K. Abramovich
Author Affiliations +
Abstract
Transfer of a layer layout from a reticle onto a photoresist-covered wafer using stepper exposure systems, can prove to be a challenging process to handle. This task becomes even more challenging when reaching the backend stages of the process, where the wafer topography variations at the wafer edge reach their maximum values. In advanced processes, where superposition of the exposure system focus plane and the wafer plane is critical, the focus is measured for every field before exposure is carried out, and the focus position of the exposure tool corrected. This can become complicated when the wafer edge is approached, and the focusing system measures a point or points, which do not represent the majority of the field plane. The outcome of the above can be an out of focus field exposure, resulting in feature degradation on the wafer, which in turn will be translated directly to wafer yield loss. The aim of this paper is to describe the achievement of yield optimization on various wafer layouts through the evaluation of various stepper focus algorithms, verification systems used to check the effectiveness of the fix, the follow-up table concept used for ease of fix validation, and eventually, the probe yield results of the chosen focus algorithm compared to those achieved prior to the optimization.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Anna Eidelman, Avi Blau, and Irit K. Abramovich "Optimization method of edge shot yield for various wafer layouts", Proc. SPIE 5375, Metrology, Inspection, and Process Control for Microlithography XVIII, (24 May 2004); https://doi.org/10.1117/12.535201
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Cited by 2 scholarly publications.
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KEYWORDS
Semiconducting wafers

Sensors

Inspection

Atrial fibrillation

Metals

Scanning electron microscopy

Optimization (mathematics)

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