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Browse Prior Art Database

Critical Image Measurement Vernier

IP.com Disclosure Number: IPCOM000053114D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Predatsch, J: AUTHOR [+2]

Abstract

A vernier scale arrangement is fabricated on masks and wafers to allow critical image measurement utilizing a simple microscope fitted with a cross hair eyepiece. Since critical images are routinely measured on the manufacturing line, the present technique using a vernier scale and simple microscope permits fast measurement utilizing simple techniques which obviate the need for any special equipment or highly skilled operation.

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Critical Image Measurement Vernier

A vernier scale arrangement is fabricated on masks and wafers to allow critical image measurement utilizing a simple microscope fitted with a cross hair eyepiece. Since critical images are routinely measured on the manufacturing line, the present technique using a vernier scale and simple microscope permits fast measurement utilizing simple techniques which obviate the need for any special equipment or highly skilled operation.

The critical image vernier is shown in Fig 1. The vernier is made during wafer or mask fabrication wherein, for example, an electron write beam forms each line from a defined center position, as shown in Fig 1. Variations in line width from the critical image are determined by referencing one array of fabricated lines against a second array of fabricated lines. As shown in Fig 1, the width S of each line corresponds to the critical image dimension, while 2S corresponds to the center to center dimension between lines. As can be seen, individual lines of the bottom row of lines in fig 1, are incrementally offset from respective lines of the top row of lines by an amount d going from right to left. Thus, the furthermost right line 11 in the bottom row is on line with line 13 in the top row, as shown by the legend zero edge. Proceeding to the left, the bottom row of lines is progressively offset from the top row of lines in multiples of d. It should be appreciated that the vernier scale arrangement shown in fig 1, represents the case where the critical image dimension is, in fact, S.

Conversely, fig 2, shows an example where...