Paper
5 July 2000 Variable-threshold optical proximity correction (OPC) models for high-performance 0.18-μm process
Hongmei Liao, Shane R. Palmer, Kayvan Sadra
Author Affiliations +
Abstract
The recent development of lithographic resolution enhancement techniques of optical proximity correction (OPC) and phase shift masks (PSM) enable sprinting critical dimension (CD) features that are significantly smaller than the exposure wavelength. In this paper, we present a variable threshold OPC model that describes how a pattern configuration transfers to the wafer after resist and etch processes. This 0.18 micrometers CMOS technology utilizes isolation with pitches of active device regions below 0.5 micrometers . The effective gate length on silicon is in the range of 0.11 to 0.18 micrometers . The OPC model begins with a Hopkin's formula for aerial image calculation and is tuned to fit the measured CD data, using a commercially available software. The OPC models are anchored at a set of selected CD dat including linearity, line-end pullback, and linewidth as a function of pitch. It is found that the threshold values inferred from measured CD dat vary approximately linearly with the slope of aerial image. The accuracy of the model is illustrated by comparing the simulated contour using the OPC model and measured SEM image. The implementation of OPC models at both active and gate is achieved using two approaches: (1) to optimize the mask bias and sizes of hammerhead and serifs via a rule based approach; and (2) to correct the SRAM cell layouts by OPC model. The OPC models developed have been successfully applied to 0.18 micrometers technology in a prototyping environment.
© (2000) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Hongmei Liao, Shane R. Palmer, and Kayvan Sadra "Variable-threshold optical proximity correction (OPC) models for high-performance 0.18-μm process", Proc. SPIE 4000, Optical Microlithography XIII, (5 July 2000); https://doi.org/10.1117/12.388938
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CITATIONS
Cited by 3 scholarly publications and 2 patents.
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KEYWORDS
Optical proximity correction

Semiconducting wafers

Data modeling

Scanning electron microscopy

Etching

Critical dimension metrology

Photomasks

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