Browse Prior Art Database

Extending the Utility of Current Generation Scanning Photolithographic Tools

IP.com Disclosure Number: IPCOM000060172D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Chappelow, RE: AUTHOR

Abstract

For the purpose of extending the utility of current generation photolithographic scanning manufacturing equipment, a method is proposed to optimize the printing of wafers requiring both large and small images on the same product. The three current criteria for measuring the utility of photolithographic tools used in manufacturing are: throughput, resolution and overlay. This proposal concerns the extendibility of the resolution parameter. The ability of an optical system to transmit images of a given size is contained in a measurement known as the Optical Transfer Function (OTF), and the primary component of the OTF is the Modulation Transfer Function (MTF). The figure is a plot of values from 0-1 of the MTF (resolution) vs. Decreasing Image Size. Observe that the MTF falls off as image size decreases, i.e.

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Extending the Utility of Current Generation Scanning Photolithographic Tools

For the purpose of extending the utility of current generation photolithographic scanning manufacturing equipment, a method is proposed to optimize the printing of wafers requiring both large and small images on the same product. The three current criteria for measuring the utility of photolithographic tools used in manufacturing are: throughput, resolution and overlay. This proposal concerns the extendibility of the resolution parameter. The ability of an optical system to transmit images of a given size is contained in a measurement known as the Optical Transfer Function (OTF), and the primary component of the OTF is the Modulation Transfer Function (MTF). The figure is a plot of values from 0-1 of the MTF (resolution) vs. Decreasing Image Size. Observe that the MTF falls off as image size decreases, i.e., large images can be reproduced with good fidelity and small images can not. By suitable optical means, the MTF in certain regions of the curve may be raised at the expense of other regions of the curve. It is relatively easy to transmit large images; it is possible to enhance transmission of small images; it is not generally possible to adequately transmit both large and small images simultaneously. By partitioning of masks or reticle according to image size, producing two masks, i.e., one containing small images and one containing large images and transmitting these conflicting patt...