scispace - formally typeset
Search or ask a question
Author

Mark J. Wihl

Bio: Mark J. Wihl is an academic researcher from KLA-Tencor. The author has contributed to research in topics: Reticle & Photolithography. The author has an hindex of 7, co-authored 16 publications receiving 691 citations.

Papers
More filters
Patent
11 Jul 1995
TL;DR: In this paper, a transmissive substrate is illuminated by a laser through an optical system comprised of a laser scanning system, individual transmitted and reflected light collection optics and detectors collect and generate signals representative of the light transmitted by the substrate as the substrate is scanned repeatedly in one axis in a serpentine pattern.
Abstract: A method and apparatus for inspecting patterned transmissive substrates, such as photomasks, for unwanted particles and features occurring on the transmissive, opaque portions and at the transition regions of the opaque and transmissive portions of the substrate. A transmissive substrate is illuminated by a laser through an optical system comprised of a laser scanning system, individual transmitted and reflected light collection optics and detectors collect and generate signals representative of the light transmitted and reflected by the substrate as the substrate is scanned repeatedly in one axis in a serpentine pattern by a laser beam which is focused on the patterned substrate surface. The defect identification of the substrate is performed using only those transmitted and reflected light signals, and other signals derived from them, such as the second derivative of each of them. The actual defect identification is then performed by comparing combinations of at least two of those measured and derived signals. Simultaneously, defect and particle inspection using the same measured transmitted and reflected light signals. Additionally, phase shift and line widths on the substrate can also be performed simultaneously using the same transmitted light signal that is collected for defect analysis.

251 citations

Patent
Mark J. Wihl1, Tao-Yi Fu1, Marek Zywno1, Damon F. Kvamme1, Michael E Fein1 
20 Aug 1992
TL;DR: In this article, an automated photomask inspection apparatus including an XY state (12) for transporting a substrate (14) under test in a serpentine path in an XY plane, an optical system (16) comprising a laser (30), a transmission light detector (34), a reflected light detector(36), optical elements defining reference beam paths and illuminating beam paths between the laser, the substrate and the detectors and an acousto-optical beam scanner (40, 42) for reciprocatingly scanning the illuminating and reference beams relative to the substrate surface, and an electronic control
Abstract: An automated photomask inspection apparatus including an XY state (12) for transporting a substrate (14) under test in a serpentine path in an XY plane, an optical system (16) comprising a laser (30), a transmission light detector (34), a reflected light detector (36), optical elements defining reference beam paths and illuminating beam paths between the laser, the substrate and the detectors and an acousto-optical beam scanner (40, 42) for reciprocatingly scanning the illuminating and reference beams relative to the substrate surface, and an electronic control, analysis and display system for controlling the operation of the stage and optical system and for interpreting and storing the signals output by the detectors. The apparatus can operate in a die-to-die comparison mode or a die-to-database mode.

201 citations

Patent
11 Jan 2007
TL;DR: In this paper, a model of an exposure lithography system for chip fabrication is adapted to accommodate the band limited mask pattern as an input which is input into the model to obtain an aerial image of the mask pattern that is processed with a photoresist model yielding a resist-modeled image.
Abstract: A method for identifying lithographically significant defects. A photomask is illuminated to produce images that experience different parameters of the reticle as imaged by an inspection tool. Example parameters include a transmission intensity image and a reflection intensity image. The images are processed together to recover a band limited mask pattern associated with the photomask. A model of an exposure lithography system for chip fabrication is adapted to accommodate the band limited mask pattern as an input which is input into the model to obtain an aerial image of the mask pattern that is processed with a photoresist model yielding a resist-modeled image. The resist-modeled image is used to determine if the photomask has lithographically significant defects.

51 citations

Patent
David S. Alles1, Mark J. Wihl1, Stan Stokowski1, Yalin Xiong1, Damon F. Kvamme1 
06 May 2008
TL;DR: In this article, a method for detecting and classifying defects on a reticle is described, which consists of detecting the defects on the reticle using one or more of the images acquired at the first condition.
Abstract: Methods for detecting and classifying defects on a reticle are provided. One method includes acquiring images of the reticle at first and second conditions during inspection of the reticle. The first condition is different than the second condition. The method also includes detecting the defects on the reticle using one or more of the images acquired at the first condition. In addition, the method includes classifying an importance of the defects detected on the reticle using one or more of the images acquired at the second condition. The detecting and classifying steps are performed substantially simultaneously during the inspection.

49 citations

Proceedings ArticleDOI
Carl Hess1, Mark J. Wihl1, Rui-fang Shi1, Yalin Xiong1, Song Pang1 
30 May 2008
TL;DR: WPI as mentioned in this paper is a state-of-the-art detector for high-resolution reticle inspection that uses a modeled image of how the mask would actually print in the photoresist, which has the effect of reducing sensitivity to non-printing defects while enabling higher sensitivity focused in high MEEF areas.
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.

42 citations


Cited by
More filters
Patent
07 Jul 2005
TL;DR: In this article, a support synthesized with polymer sequences at known locations according to the methods disclosed in U.S. Pat. No. 5,143,854 and PCT WO 92/10092 or others, can be detected by exposing selected regions of sample 1500 to radiation from a source 1100 and detecting the emission therefrom, and repeating the steps of exposition and detection until the sample is completely examined.
Abstract: Labeled targets on a support synthesized with polymer sequences at known locations according to the methods disclosed in U.S. Pat. No. 5,143,854 and PCT WO 92/10092 or others, can be detected by exposing selected regions of sample 1500 to radiation from a source 1100 and detecting the emission therefrom, and repeating the steps of exposition and detection until the sample is completely examined.

795 citations

Patent
David Stern1, Peter Fiekowsky1
17 Sep 2008
TL;DR: In this article, fluorescently marked targets are detected by exposing selected regions of the substrate 230 to light from a light source 100 and detecting the photons from the light fluoresced therefrom, and repeating the steps of exposure and detection until the substrate is completely examined.
Abstract: Fluorescently marked targets bind to a substrate 230 synthesized with polymer sequences at known locations. The targets are detected by exposing selected regions of the substrate 230 to light from a light source 100 and detecting the photons from the light fluoresced therefrom, and repeating the steps of exposure and detection until the substrate 230 is completely examined. The resulting data can be used to determine binding affinity of the targets to specific polymer sequences.

532 citations

Patent
Khurram Zafar1, Sagar A. Kekare1, Ellis Chang1, Allen Park1, Peter Rose1 
20 Nov 2006
TL;DR: In this paper, a computer-implemented method for binning defects detected on a wafer includes comparing portions of design data proximate positions of the defects in design data space.
Abstract: Various methods and systems for utilizing design data in combination with inspection data are provided. One computer-implemented method for binning defects detected on a wafer includes comparing portions of design data proximate positions of the defects in design data space. The method also includes determining if the design data in the portions is at least similar based on results of the comparing step. In addition, the method includes binning the defects in groups such that the portions of the design data proximate the positions of the defects in each of the groups are at least similar. The method further includes storing results of the binning step in a storage medium.

528 citations

Patent
11 Jul 2002
TL;DR: In this article, a template is brought into contact with the liquid and the cured liquid includes an imprint of any patterns formed in the template, and the remainder of the substrate is imprinted by moving the template to a different portion of the template and repeating the imprint lithography process.
Abstract: The present invention is directed to methods for patterning a substrate by imprint lithography. Imprint lithography is a process in which a liquid is dispensed onto a substrate. A template is brought into contact with the liquid and the liquid is cured. The cured liquid includes an imprint of any patterns formed in the template. In one embodiment, the imprint process is designed to imprint only a portion of the substrate. The remainder of the substrate is imprinted by moving the template to a different portion of the template and repeating the imprint lithography process.

352 citations

Patent
18 Sep 1997
TL;DR: In this article, the phase shift mask and the single phase structure mask are derived from a set of masks used in a larger minimum dimension process technology and used for shrinking integrated circuit designs.
Abstract: A method and apparatus for creating a phase shifting mask and a structure mask for shrinking integrated circuit designs. One embodiment of the invention includes using a two mask process. The first mask is a phase shift mask and the second mask is a single phase structure mask. The phase shift mask primarily defines regions requiring phase shifting. The single phase structure mask primarily defines regions not requiring phase shifting. The single phase structure mask also prevents the erasure of the phase shifting regions and prevents the creation of undesirable artifact regions that would otherwise be created by the phase shift mask. Both masks are derived from a set of masks used in a larger minimum dimension process technology.

347 citations