Kla Tencor Corporation

Wei-Te Cheng

Eran Amit

Einat Peled

Yuval Lamhot

Noga Sella

Alexander Svizher

Ido Adam

A method of determining overlay ('OVL') in a pattern in a semiconductor wafer manufacturing process comprises capturing images from a cell in a metrology target formed in at least two different layers in the wafer with parts of the target offset in opposing directions with respect to corresponding parts in a different layer. The images may be captured using radiation of multiple different wavelengths, each image including +1 and &#x2212;1 diffraction patterns. A first and second differential signal may be determined for respective pixels in each image by subtracting opposing pixels from the +1 and &#x2212;1 diffraction orders for each of the multiple wavelengths. An OVL for the respective pixels may be determined based on analyzing the differential signals from multiple wavelengths simultaneously. Then an OVL for the pattern may be determined as a weighted average of the OVL of the respective pixels.

Overlay measurement using multiple wavelengths

Methods applicable in metrology modules and tools are provided, which enable adjusting metrology measurement parameters with respect to process variation, without re-initiating metrology recipe setup. Methods comprise, during an initial metrology recipe setup, recording a metrology process window and deriving baseline information therefrom, and during operation, quantifying the process variation with respect to the baseline information, and adjusting the metrology measurement parameters within the metrology process window with respect to the quantified process variation. The quick adjustment of metrology parameters avoids metrology-related process delays and releases prior art bottlenecks related thereto. Models of effects of various process variation factors on the metrology measurements may be used to enhance the derivation of required metrology tuning and enable their application with minimal delays to the production process.

Quick adjustment of metrology measurement parameters according to process variation

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Taichung, Taiwan

Wei-Te Cheng