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E-Beam Three-Mark Registration for Vertical Wiring Processes

IP.com Disclosure Number: IPCOM000042711D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Anderson, G: AUTHOR [+4]

Abstract

There are seven required E-beam lithography levels (K, L1, L2, M, V1, V2, X) in the Vertical Wiring Process (VWP) for forming multilevel metallurgy. One problem with some approaches is that E-beam registration presents difficulties at the V1 level. This occurs because of the extremely thick lift-off structures required in some such processes and because of the degradation of the registration mark. Such an E-beam registration approach is as follows: K level Register to a shallow A registration mark through a lift-off structure. Define an up B mark to allow registration at the following L1 level. L1 level Register to the up B registration mark through a lift-off structure. L2 level Register to the 1 um up B mark through a resist film. M level Register to the up B registration mark through a lift-off structure.

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E-Beam Three-Mark Registration for Vertical Wiring Processes

There are seven required E-beam lithography levels (K, L1, L2, M, V1, V2, X) in the Vertical Wiring Process (VWP) for forming multilevel metallurgy. One problem with some approaches is that E-beam registration presents difficulties at the V1 level. This occurs because of the extremely thick lift-off structures required in some such processes and because of the degradation of the registration mark. Such an E-beam registration approach is as follows: K level Register to a shallow A registration mark through a lift-off structure. Define an up B mark to allow registration at the following L1 level. L1 level Register to the up B registration mark through a lift-off structure. L2 level Register to the 1 um up B mark through a resist film. M level Register to the up B registration mark through a lift-off structure. The registration signal starts to degrade at this level due to decreasing mark height. V1 level The process may call for a lift-off structure identical to the L1 level. Registration may fail at the V1 level due to decreasing mark height. Alternate E-beam Registration Method This method is basically identical to the above-described prior E-beam registration strategy through and including L2 level except that the condensed type marks (Fig. 1B) are substituted for the Fig. 1A type marks to enable one to insert a third set of registration marks with no increase in space required. In fact, the overall ar...