Ms. Song Pang Profile

Song Pang

Senior Manager, Product Marketing at KLA Corp

SPIE Involvement:

Author

Publications (5)

Proceedings Article | 17 October 2008 Paper

Wafer plane inspection with soft resist thresholding

Carl Hess, Rui-fang Shi, Mark Wihl, Yalin Xiong, Song Pang

Proceedings Volume 7122, 71221C (2008) https://doi.org/10.1117/12.801866

KEYWORDS: Inspection, Semiconducting wafers, Photomasks, Printing, Reticles, Defect detection, Wafer inspection, SRAF, Image resolution, Lithography

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Wafer Plane Inspection (WPI) is an inspection mode on the KLA-Tencor TeraSca^TM platform that uses the high signalto- noise ratio images from the high numerical aperture microscope, and then models the entire lithographic process to enable defect detection on the wafer plane[1]. This technology meets the needs of some advanced mask manufacturers to identify the lithographically-significant defects while ignoring the other non-lithographically-significant defects. WPI accomplishes this goal by performing defect detection based on a modeled image of how the mask features would actually print in the photoresist. There are several advantages to this approach: (1) the high fidelity of the images provide a sensitivity advantage over competing approaches; (2) the ability to perform defect detection on the wafer plane allows one to only see those defects that have a printing impact on the wafer; (3) the use of modeling on the lithographic portion of the flow enables unprecedented flexibility to support arbitrary illumination profiles, process-window inspection in unit time, and combination modes to find both printing and non-printing defects. WPI is proving to be a valuable addition to the KLA-Tencor detection algorithm suite. The modeling portion of WPI uses a single resist threshold as the final step in the processing. This has been shown to be adequate on several advanced customer layers, but is not ideal for all layers. Actual resist chemistry has complicated processes including acid and base-diffusion and quench that are not consistently well-modeled with a single resist threshold. We have considered the use of an advanced resist model for WPI, but rejected it because the burdensome requirements for the calibration of the model were not practical for reticle inspection. This paper describes an alternative approach that allows for a "soft" resist threshold to be applied that provides a more robust solution for the most challenging processes. This approach is just finishing beta testing with a customer developing advanced node designs.

Proceedings Article | 17 October 2008 Paper

Wafer plane inspection evaluated for photomask production

Emily Gallagher, Karen Badger, Mark Lawliss, Yutaka Kodera, Jaione Tirapu Azpiroz, Song Pang, Hongqin Zhang, Eugenia Eugenieva, Chris Clifford, Arosha Goonesekera, Yibin Tian

Proceedings Volume 7122, 71221B (2008) https://doi.org/10.1117/12.801945

KEYWORDS: Photomasks, Inspection, Semiconducting wafers, Finite-difference time-domain method, Wafer inspection, Manufacturing, Printing, Lithography, Reticles, Optical proximity correction

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Proceedings Article | 17 October 2008 Paper

High resolution inspection with wafer plane die: database defect detection

Carl Hess, Mark Wihl, Rui-fang Shi, Yalin Xiong, Song Pang

Proceedings Volume 7122, 71221A (2008) https://doi.org/10.1117/12.801867

KEYWORDS: Inspection, Semiconducting wafers, Photomasks, Reticles, Defect detection, Printing, Scanners, Wafer inspection, Image restoration, Lithography

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Proceedings Article | 19 May 2008 Paper

Wafer plane inspection for advanced reticle defects

Rajesh Nagpal, Firoz Ghadiali, Jun Kim, Tracy Huang, Song Pang

Proceedings Volume 7028, 70281H (2008) https://doi.org/10.1117/12.793058

KEYWORDS: Inspection, Photomasks, Semiconducting wafers, Reticles, Defect inspection, Wafer inspection, Defect detection, Lithography, Critical dimension metrology, Contamination

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Proceedings Article | 19 May 2008 Paper

A novel approach: high resolution inspection with wafer plane defect detection

Carl Hess, Mark Wihl, Rui-fang Shi, Yalin Xiong, Song Pang

Proceedings Volume 7028, 70281F (2008) https://doi.org/10.1117/12.793056

KEYWORDS: Inspection, Semiconducting wafers, Photomasks, Reticles, Defect detection, Printing, Scanners, Wafer inspection, Image restoration, Lithography

Read Abstract +

High Resolution reticle inspection is well-established as a proven, effective, and efficient means of detecting yield-limiting mask defects as well as defects which are not immediately yield-limiting yet can enable manufacturing process improvements. Historically, RAPID products have enabled detection of both classes of these defects. The newly-developed Wafer Plane Inspection (WPI) detector technology meets the needs of some advanced mask manufacturers to identify the lithographically-significant defects while ignoring the other non-lithographically-significant defects. Wafer Plane Inspection accomplishes this goal by performing defect detection based on a modeled image of how the mask features would actually print in the photoresist. This has the effect of reducing sensitivity to non-printing defects while enabling higher sensitivity focused in high MEEF areas where small reticle defects still yield significant printing defects on wafers. WPI is a new inspection mode that has been developed by KLA-Tencor and is currently under test with multiple customers. It employs the same transmitted and reflected-light high-resolution images as the industry-standard high-resolution inspections, but with much more sophisticated processing involved. A rigorous mask pattern recovery algorithm is used to convert the transmitted and reflected light images into a modeled representation of the reticle. Lithographic modeling of the scanner is then used to generate an aerial image of the mask. This is followed by resist modeling to determine the exposure of the photoresist. The defect detectors are then applied on this photoresist plane so that only printing defects are detected. Note that no hardware modifications to the inspection system are required to enable this detector. The same tool will be able to perform both our standard High Resolution inspections and the Wafer Plane Inspection detector. This approach has several important features. The ability to ignore non-printing defects and to apply additional effective sensitivity in high MEEF areas enables advanced node development. In addition, the modeling allows the inclusion of important polarization effects that occur in the resist for high NA operation. This allows for the results to better match wafer print results compared to alternate approaches. Finally, the simulation easily allows for the application of arbitrary illumination profiles. With this approach, users of WPI can make use of unique or custom scanner illumination profiles. This allows the more precise modeling of profiles without inspection system hardware modification or loss of company intellectual property. This paper examines WPI in Die:Die mode. Future work includes a review of Die:Database WPI capability.

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