EP0358936A2
Expired / Lapsed
EP
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Method of and apparatus for measuring film thickness
Assignee: Dainippon Screen Manufacturing Co Ltd
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Filing: 1989-08-07
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Granted: —
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Expires: 2009-08-07
Abstract
Abstract The present invention provides a method of and an apparatus for measuring the thickness of a first thin film (46) which is the uppermost layer of a sample (5) formed by two or more stacked thin films (42, 44, 46). According to the invention, light (I′) which is transmitted through the first thin (46) film but absorbed by a second thin film (44) positioned directly under the first thin film is applied to the sample (5) and the spectrum of light (R₁′, R₂′) reflected by the sample is detected to correctly obtain thickness of the first thin film on the basis of the detected spectrum
Inventors
- 👤 Noriyuki Dainippon Screen Mfg. Co. Ltd. Kondo
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 05:17
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/0616; G01B11/0625
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
138 words
A method of measuring the thickness of a first thin film (46) which is an uppermost layer of a sample (5) formed by two or more stacked thin films (42, 44, 46), said method comprising: a first step of applying light (I`) to said sample (5); a second step of detecting the spectrum of light (R₁′, R₂′) reflected by said sample; and a third step of obtaining the thickness of said first thin film (46) on the basis of said spectrum detected in said second step; said method being characterised in that said light (I′) applied to said sample (5) in said first step has a wave length such that said light (I′) is transmitted through said first thin film (46) but is absorbed by a second thin film (44) located directly under said first thin film (46).
Claim 2
Independent Claim
138 words
A method of measuring the thickness of a first thin film (46) which is an uppermost layer of a sample (5) formed by two or more stacked thin films (42, 44, 46), said method comprising: a first step of applying light (I`) to said sample (5); a second step of detecting the spectrum of light (R₁′, R₂′) reflected by said sample; and a third step of obtaining the thickness of said first thin film (46) on the basis of said spectrum detected in said second step; said method being characterised in that said light (I′) applied to said sample (5) in said first step has a wave length such that said light (I′) is transmitted through said first thin film (46) but is absorbed by a second thin film (44) located directly under said first thin film (46).
Claim 3
Dependent Claim
73 words
A method in accordance with claim 1, comprising an initial step of obtaining correlation date showing a correlation between the character of the light reflected by said sample (5) and the thickness value of said first thin film (46); and obtaining the thickness of said first thin film (46) in said third step on the basis of said correlation data obtained in said initial step and said spectrum detected in said second step.
Claim 4
Dependent Claim
46 words
A method in accordance with claim 2, wherein said initial step comprises storing optical constants of said first and second thin films (46, 44) in a memory means (34) and obtaining said correlation data by arithmetically processing said optical constants stored in said memory means (34).
Claim 5
Dependent Claim
18 words
A method in accordance with claim 3, wherein said optical constants include indices of refraction and absorption coefficients.
Claim 6
Dependent Claim
39 words
A method in accordance with claim 4, wherein said correlation data comprises correlation data showing a correlation between the energy value of light (R₁′, R₂′) reflected by said sample (5) and thickness value of said first thin film (46).
Claim 7
Dependent Claim
45 words
A method in accordance with claim 4 or 5, wherein said correlation data comprises correlation data showing a correlation between the thickness value of said first thin film (46) and an extreme value of the spectrum of light (R₁′, R₂′) reflected by said sample (5).
Claim 8
Independent Claim
30 words
A method in accordance with any preceding claim, wherein the wave length of said light (I′), applied to said sample (5) in said first step lies in the ultraviolet region.
Claim 9
Independent Claim
154 words
An apparatus for measuring the thickness of a first thin film (46) which is an uppermost layer of a sample (5) formed by two or more stacked thin films (42, 44, 46), said apparatus comprising: means (200, 350) for applying light (L VS , L UV ) to said sample; means (32) for detecting the spectrum of light (L S ) reflected by said sample (5); and means (34) for obtaining the thickness of said first thin film (46) on the basis of said spectrum detected by said detecting means (32); said apparatus being characterised in that said light applying means (200, 300) comprises means (28, 30, 14) for applying to said sample (5) light (L UV ) having a wave length such that said light (L UV ) is transmitted through said first thin film (46) but is absorbed by a second thin film (44) located directly under said first thin film (46).
Claim 10
Independent Claim
154 words
An apparatus for measuring the thickness of a first thin film (46) which is an uppermost layer of a sample (5) formed by two or more stacked thin films (42, 44, 46), said apparatus comprising: means (200, 350) for applying light (L VS , L UV ) to said sample; means (32) for detecting the spectrum of light (L S ) reflected by said sample (5); and means (34) for obtaining the thickness of said first thin film (46) on the basis of said spectrum detected by said detecting means (32); said apparatus being characterised in that said light applying means (200, 300) comprises means (28, 30, 14) for applying to said sample (5) light (L UV ) having a wave length such that said light (L UV ) is transmitted through said first thin film (46) but is absorbed by a second thin film (44) located directly under said first thin film (46).
Claim 11
Dependent Claim
37 words
An apparatus in accordance with claim 8, wherein said light applying means (200, 300) includes a lamp (28) for applying light (L UV ) which has a wave length in the ultraviolet region to said sample (5),.
Claim 12
Dependent Claim
15 words
An apparatus in accordance with claim 9, wherein said lamp (28) is a deuterium lamp.
Claim 13
Dependent Claim
15 words
An apparatus in accordance with claim 9, wherein said lamp (28) is a xenon lamp.
References Cited (Backward Citations)
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