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Fabrication of Overlapping Patterns From a Single Exposure in X Ray Lithography

IP.com Disclosure Number: IPCOM000082556D
Original Publication Date: 1974-Dec-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Feder, R: AUTHOR [+2]

Abstract

A method has been devised for obtaining overlapping patterns using a single x-ray exposure.

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Fabrication of Overlapping Patterns From a Single Exposure in X Ray Lithography

A method has been devised for obtaining overlapping patterns using a single x-ray exposure.

Sometimes it may be desired to overlay only a part of a doped region of a semiconductor with metal after the semiconductor has been doped. Such overlay should take place without having to rely on the registration of masks. To achieve such an overlapping pattern, it is necessary to begin by sending x-rays 2 through a mask 4 that is inserted between the x-rays and a substrate 6 and a resist layer
8.

The x-ray absorbing mask 4 has different thicknesses T1, T2, T3, etc. so that thin regions of the mask, such as T1, will allow intense x-rays to expose the resist 8 beneath it, whereas the thickest regions T3 of the mask will not allow x- rays to expose the resist, and intermediate thicknesses T2 of the mask 4 will allow intermediate intensities of x-rays to expose the resist 8.

During development of the resist, the most exposed regions of resist 8 are washed away, as seen in region R1 of step B, the less exposed regions R2 are partially washed away, whereas regions R3 are negligibly affected.

In step B, after a passageway has been made in the resist 8, ions 10 are implanted in the substrate 6 beneath the passageway. In step C, an additional coat of resist 12 is deposited over the previously developed resist 8. In step D sufficient resist 12 is removed so that the partially developed region R2 can be ...