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Photomask

About: Photomask is a research topic. Over the lifetime, 7917 publications have been published within this topic receiving 54524 citations. The topic is also known as: photoreticle & reticle.


Papers
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Proceedings ArticleDOI
28 May 2004
TL;DR: In this article, a more accurate model was proposed that consists of a fixed-width, locally-determined boundary layer of imaginary transmission coefficient added to every edge of the initial "thin mask" approximation.
Abstract: Sub-wavelength lithography places a serious limitation on the conventional "thin mask" approximation of the field immediately behind the patterned mask. This approximation fails to account for the increasingly important topographical effects of the mask or "thick mask" effects. This approximation of the photomask near-fields results from the direct application of Kirchhoff Boundary Conditions, which multiply the incident field by a binary transmission function of the patterned mask. Polarization dependent edge diffraction effects, as well as phase and amplitude transmission errors that arise from the vector nature of light, and the finite thickness of the substrate and chrome layers, produce significant errors in the scalar simulations of the lithographic image. Based on the comparison of aerial images at the wafer plane produced by both rigorous electromagnetic solutions of the field on the mask and their "thin mask" counterparts, a more accurate model is proposed that consists of a fixed-width, locally-determined boundary layer of imaginary transmission coefficient added to every edge of the initial "thin mask" approximation. The accuracy of the resultant Boundary Layer model has been exhaustively tested against rigorously simulated aerial images of isolated as well as periodic features of very different profiles and dimensions. The conclusion being that this simple approach is capable of modeling "thick mask" effects at both 248nm and 193nm wavelength and high NA lithography. This greatly improves the accuracy of aerial image computation in photolithography simulations at a reasonable computational cost.

15 citations

Patent
15 Aug 2001
TL;DR: In this paper, a photomask having an opaque pattern made of metal and a polysilicon mask having an opacity made of a resist film are used to improve the performance of a semiconductor integrated circuit.
Abstract: Productivity of a semiconductor integrated circuit device is improved. According to how many times the photomask is used, a photomask having an opaque pattern made of metal and a photomask having an opaque pattern made of a resist film are properly used, and thereby an exposure treatment is performed.

15 citations

Patent
Ho-Chul Kim1
03 Jan 2006
TL;DR: In this article, an inner, non-printing feature is adapted to enhance image contrast at the first and second critical edges of the printable element for the given wavelength of exposure light during a photolithographic process.
Abstract: Photolithographic methods for semiconductor manufacturing are provided wherein photomask structures are designed to provide increased lithographic process windows for printing sub-wavelength features. In one aspect, a photomask includes a mask substrate transparent to exposure light of a given wavelength, and a mask pattern formed on a surface of the substrate. The mask pattern comprises a printable element defined by a first and second critical edge, wherein the printable element includes an inner, non-printing feature formed between the first and second critical edges. The inner, non-printing feature is adapted to enhance image contrast at the first and second critical edges of the printable element for the given wavelength of exposure light during a photolithographic process. The non-printing feature comprises a space feature that exposes a region of the mask substrate aligned to the printable element between the first and second critical edges, and a trench feature that is formed in the mask substrate and aligned to the space feature.

15 citations

Patent
09 Oct 1984
TL;DR: In this article, a method for fabricating unit patterns each having the same shape and size for a semiconductor die on a photomask pattern area of a photOMask is presented.
Abstract: A method for fabricating unit patterns each having the same shape and size for a semiconductor die on a photomask pattern area of a photomask. By designating a matrix having rows and columns for the unit patterns on the photomask pattern area, the fabrication is made in the order of two exposing modes. In the first exposing mode, the fabrication is made by exposing respectively an optical image for the unit pattern on selected several matrix elements placed as far as possible away from each other in the photomask pattern area; in the second exposing mode, the exposure of the unit pattern is made along the row of the matrix elements except for the elements which have been exposed in the first exposing mode, until the exposure for all unit patterns are made by shifting sequentially the exposure to the next row. These exposures of the unit patterns, thusly are made with vernier pattern producing overlapped vernier patterns when the exposures of the first and the second exposing modes are made. Thus, after all the unit patterns have been printed on the photomask base plate, an inspection of the positions of the unit patterns can be made by observing some of the overlapping vernier patterns and measuring the accumulated shears which are produced in the second exposing mode.

14 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202322
202281
202150
2020124
2019179
2018195