Browse Prior Art Database

Method to Produce Dual-Wavelength Masks

IP.com Disclosure Number: IPCOM000036304D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 84K

Publishing Venue

IBM

Related People

Burns, FC: AUTHOR [+2]

Abstract

Disclosed is a method to generate a mask which can be used for resist compositions which are sensitive to two distinctly different bandwidths of radiation. There are three requirements for such a mask. One, some areas of the mask must transmit all light. Two, some areas of the mask must transmit no light. Three, selected areas of the mask transmit light of certain wavelengths but must not transmit light at all other wavelengths. Such a mask can be constructed by using a combination of dielectric and metal coatings.

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Method to Produce Dual-Wavelength Masks

Disclosed is a method to generate a mask which can be used for resist compositions which are sensitive to two distinctly different bandwidths of radiation. There are three requirements for such a mask. One, some areas of the mask must transmit all light. Two, some areas of the mask must transmit no light. Three, selected areas of the mask transmit light of certain wavelengths but must not transmit light at all other wavelengths. Such a mask can be constructed by using a combination of dielectric and metal coatings.

The method to construct a mask which satisfies all three requirements is the subject of this publication. The mask substrate must transmit all wavelengths of interest. A dielectric coating is applied to the substrate. The dielectric coating is designed to be transparent over a certain predetermined wavelength range and opaque over a second wavelength range. A compatible metal coating is applied to the dielectric coating in order to provide a completely opaque layer.

Standard photolithographic techniques are used to remove the metal from desired areas. The result of this process is to expose the underlying dielectric coating in all areas which will be either totally or partially transmitting.

A second photolithographic step is performed to remove the dielectric material from those areas which are to be totally transmitting. The photoresist protects the chromium (Cr) remaining from the previous step and the dielect...