Browse Prior Art Database

Edge Alignment and Edge Vernier Alignment Mark for Thin Film Head Fabrication

IP.com Disclosure Number: IPCOM000038217D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Chen, MM: AUTHOR [+5]

Abstract

Disclosed is an edge alignment mark design to improve the alignment accuracy for devices where the edge-to-edge alignment between levels is critical.

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Edge Alignment and Edge Vernier Alignment Mark for Thin Film Head Fabrication

Disclosed is an edge alignment mark design to improve the alignment accuracy for devices where the edge-to-edge alignment between levels is critical.

In the fabrication of the devices using lithographic technique, the center-to- center alignment between device levels is normally used. This type of alignment works very well for most of the device levels. However, there are situations where edge-to-edge relationship across the levels are important, that better control of this edge-to-edge alignment will lead to device performance improvement as well as yield improvement. With conventional center-to-center alignment, the misalignment between the critical edges is equal to the sum of the photo alignment error and the process windage errors in the two corresponding levels. The windage error arising from the first mask level can be compensated by the disclosed edge-to-edge alignment mark scheme. The mask alignment accuracy can be further improved using an edge vernier alignment mark.

An edge alignment mask design is depicted in Fig. 1. Conventional center-to- center alignment is used in the X direction and edge-to-edge alignment is used in the Y direction for illustration. Dashed line represents structures in the first level. Solid line depicts the alignment mark design on the second level. Cusps shape geometry on the mask is used for the coarse alignment. Alignment is made by placing the das...