Browse Prior Art Database

Measuring the Thickness of Evaporated Layers

IP.com Disclosure Number: IPCOM000087385D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Bohg, A: AUTHOR [+3]

Abstract

A densitometric measuring arrangement, evaluating light scattered from a reference substrate on which part of the evaporated material is deposited, is used to measure the thickness of opaque single or multiple layers.

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Measuring the Thickness of Evaporated Layers

A densitometric measuring arrangement, evaluating light scattered from a reference substrate on which part of the evaporated material is deposited, is used to measure the thickness of opaque single or multiple layers.

As shown in Fig. 1, material from source 1 is vapor-deposited on target 2, forming an opaque layer 3. A transparent record carrier 5, which is moved at constant speed behind slot 6 of mask 7, is placed in evaporation chamber 4. Thus, the vapor-deposited layer on record carrier 5 is a quasi time-expanded projection of each layer on the target.

The density D of the layers on record carrier 5 is measured by the densitometric method shown in Fig. 2. Light from diffuse light source 10 impinges on record carrier 5 supported by glass plate 11. Light detector 12, extending over a certain area of the recorded layer, is in mechanical contact with record carrier 5, thus collecting light passed through and scattered by the layer. By this arrangement a linear relationship is achieved between the thickness of the layer and the measured light extinction values.

An evaluation of the records on carrier 5 is shown in Fig. 3. The density is measured at n different points, yielding partial density values Di. Thickness T of the target is calculated by multiplying the average density on record carrier 5 by factor L/w, where L is the length of the record depending on the velocity of the carrier and w is the width of the slot. T...