Kla Tencor Corporation

Kla-tencor Technologies Corporation

Lih-Huah Yiin

George Q Chen

Rui-Fang Shi

Yu Long Cao

Yalin Xiong

Mark Joseph Wihl

Bing Li

Zhengyu Wang

Jun Ye

Yen-Wen Lu

Venkatraman Iyer

Ge Cong

Pei-Chun Chiang

Vinayak Dattatreya Phalke

A method embodiment includes providing a reticle design data that specify a plurality of printable features that are formed on the wafer using the reticle and a plurality of nonprintable features that are not formed on the wafer using such reticle, wherein the reticle design data is usable to fabricate the reticle. A reduced design database is generated from the reticle design data and this reduced design database includes a description or map of the nonprintable features of the reticle, a description or map of a plurality of cell-to-cell regions of the reticle, and a grayscale reticle image that is rasterized from the reticle design data. The reduced design database, along with the reticle, is transferred to a fabrication facility so that the reduced design database is usable to periodically inspect the reticle in the fabrication facility.

Method and apparatus for database-assisted requalification reticle inspection

A detection method for a spot image based thin line detection is disclosed. The method includes a step for constructing a band limited spot image from a transmitted and reflected optical image of the mask. The spot image is calibrated to reduce noise introduced by the one or more inspection systems. Based on the band limited spot image, a non-printable feature map is generated for the non-printable features and a printable feature map is generated for the printable features. One or more test images of the mask are analyzed to detect defects on such mask. A sensitivity level of defect detection is reduced in areas of the one or more test images defined by the non-printable feature map, as compared with areas of the one or more test images that are not defined by the non-printable features map

Detection of thin lines for selective sensitivity during reticle inspection using processed images

A detection method for a spot image based thin line detection is disclosed. The method includes a step for generating a band limited spot image from a transmitted and reflected optical image of the mask. The spot image is calibrated to minimize a plurality of optical aberrations from the spot image. The spot image is restored back to a mask image to allow at least one of: a more reliable segmentation between thin line and non-thin line areas on the mask image or a more accurate line width measurement for facilitating segmentation. Thin line features and non-thin lines features are distinguished on the restored mask image. Areas containing thin line features are grown while preventing the thin line growth from encroaching the non-thin line features.

Methods and apparatus relating to the inspection of photomasks are described. In an embodiment, detection of thin line or sub-resolution assist features may be used for selective sensitivity during photomask inspection. Other embodiments are also described.

Detection of thin line for selective sensitivity during reticle inspection

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.

Method for detecting lithographically significant defects on reticles

A method and apparatus for inspecting specimens or patterned transmissive substrates, such as photomasks, for unwanted particles and features, particularly those associated with contacts, including irregularly shaped contacts. A specimen is illuminated by a laser through an optical system comprised of a laser scanning system, individual transmitted and/or reflected light collection optics and detectors collect and generate signals representative of the light transmitted by the substrate. The defect identification of the substrate is performed using those transmitted light signals. Defect identification is performed using an inspection algorithm by comparing image feature representations of a test specimen with a reference specimen, and using a boundary computer and flux comparison device to establish tight boundaries around contacts and compute flux differences between the test and reference specimen contacts. Defect sizes are reported as ratio of flux difference, and entire contacts are highlighted for review.

Closed region defect detection system

Faster and more accurate techniques for displaying images are described. The techniques can be applied in various applications that include semiconductor fabrication processes. The invention uses preprocessed images to generate a user-selected image in order to increase the speed of image processing. The invention displays the pixels forming an image using grayscale shading in order to improve the accuracy of displaying the patterns used in photolithography processes. The techniques of the present invention can be used to display images that represent lithography patterns stored within memory devices or to display images captured by inspection or metrology devices.

Visualization of photomask databases

Techniques that use the design databases used in each of the expose/etch steps during construction of phase shift masks are described. A model or reference image is rendered, accounting for systematic variations, from the design databases to represent what a layer of the PSM should look like after processing. The reference image is compared to an optically acquired image of a specimen phase shift mask to find defects. The technique of the present invention can be used to inspect EAPSM, APSM and tritone masks. The technique inspects all layers in one pass and is therefore more efficient.

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Mountain View, CA, United States of America

Lih-Huah Yiin