Browse Prior Art Database

Self Aligned Mask for Multilevel Lithography

IP.com Disclosure Number: IPCOM000085148D
Original Publication Date: 1976-Feb-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Feder, R: AUTHOR [+4]

Abstract

A method has been devised for fabricating multilevel devices using an optical or X-ray lithographic procedure that assures perfect alignment, even when there is wafer distortion due to hot processing on such wafer.

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Self Aligned Mask for Multilevel Lithography

A method has been devised for fabricating multilevel devices using an optical or X-ray lithographic procedure that assures perfect alignment, even when there is wafer distortion due to hot processing on such wafer.

In the method described herein below, the pattern to be transferred is accomplished by first fabricating a multilevel X-ray mask. Assuming that X-ray lithography is being used, an E-beam written master is made in which the exposed and developed areas are coated with an X-ray absorbing material. The E-beam continues to write on new resist areas, using subsequent writings, until the entire X-ray opaque mask has been completed.

Such an X-ray mask is employed to fabricate other multilevel masks on the back side of a substrate that will support a desired pattern on its front side. Using the dissolution properties of a resist, various areas can be coated in successive steps until a coated pattern is produced on the back side of the wafer. A blanket exposure through the back side of the masked wafer with radiation that can pass through the wafer, will expose the resist spun upon the front surface.

The use of positive or negative resists will allow a variety of patterns to be opened and processed on the front of the wafer, without distorting the mask on the back side of the wafer. Moreover, distortions in the wafer during processing,
i.e., deposition of metals at elevated temperatures through holes in developed resi...