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Optical Thickness Monitor for Continuous Vapor Deposited Film

IP.com Disclosure Number: IPCOM000061572D
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Cronin, JE: AUTHOR [+2]

Abstract

This article discloses an optical monitor wafer which is utilized to determine the thickness of conformal metal films formed by continuous vapor deposition (CVD). Current methods of measuring CVD film thickness include the use of a scanning electron microscope (SEM) and the use of the ohms/square (Rs) method of calculating resistivity. These techniques are time consuming and complex. Moreover, where sensitive elemental compositions are altered in the deposition process, the Rs method cannot be used as a means of measurement. Fig. 1 shows a plurality of holes formed in a monitor wafer which is used to optically monitor the thickness of CVD films. Note that holes of different depths and similar widths, e.g., Y1 and Y2, fill in the same time.

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Optical Thickness Monitor for Continuous Vapor Deposited Film

This article discloses an optical monitor wafer which is utilized to determine the thickness of conformal metal films formed by continuous vapor deposition (CVD). Current methods of measuring CVD film thickness include the use of a scanning electron microscope (SEM) and the use of the ohms/square (Rs) method of calculating resistivity. These techniques are time consuming and complex. Moreover, where sensitive elemental compositions are altered in the deposition process, the Rs method cannot be used as a means of measurement. Fig. 1 shows a plurality of holes formed in a monitor wafer which is used to optically monitor the thickness of CVD films. Note that holes of different depths and similar widths, e.g., Y1 and Y2, fill in the same time. A CVD film of thickness one-half X fills holes having a width X; a CVD film of thickness X will fill holes having a width 2X. Holes having a width 3X are not filled by a film thickness X. Fig. 2 is a top view of the monitor wafer. The holes are configured in incremental sizes and identified by markers. After exposing the monitor wafer to a CVD process, film thickness as deposited is determined by viewing the holes under a microscope. One can determine at a glance which hole sizes are filled and which ones are not (to thus determine film thickness) by referencing the markers above each column. More accurate film measurements can be made by increasing the number of inc...