EP0567701A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Inspection method and apparatus
Assignee: Canon Inc
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Filing: 1992-06-16
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Granted: —
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Expires: 2012-06-16
Abstract
Abstract An inspection method and apparatus is disclosed, wherein a laser beam from a laser source is separated into two orthogonal, linearly polarized lights which are then modulated at different shift frequencies and are projected on the same spot on a surface to be inspected. Scattered light resulting in response to impingement of one laser beam and resulting from depolarization attributable to a particle or fault on the surface, and zero-th order diffraction light resulting from the other laser beam, are caused to interfere with each other. The resultant interference light is detected through heterodyne detecting method, whereby a beat signal is detected only on the basis of the light depolarized by the particle or fault. This assures precise inspection of a high S/N ratio to a particle or fault on the surface.
Inventors
- 👤 Toshihiko C/O Canon Kabushiki Kaisha Tsuji
- 👤 Noriyuki C/O Canon Kabushiki Kaisha Nose
- 👤 Minoru C/O Canon Kabushiki Kaisha Yoshii
- 👤 Kyoichi C/O Canon Kabushiki Kaisha Miyazaki
- 👤 Seiji C/O Canon Kabushiki Kaisha Takeuchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 16:11
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70483; G03F7/70605; G03F7/70616; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/94; G03F7/7065; G03F7/708; G03F7/70908; G03F7/70916; G01J; G01J9/00; G01J9/02; G01J2009/0261; G01J9/04; G01N21/8806
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
135 words
An inspection apparatus based on a heterodyne method, comprising: light producing means for producing (i) a first light beam having a first state of polarization and a first wavelength, and (ii) a second light beam having a second state of polarization, different from the first state of polarization, and a second wavelength, different from the first wavelength; light projecting means for projecting at least the first light beam to a position of inspection; detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered at said position and having its state of polarization changed, by the scattering, from the first state of polarization; and signal processing means for inspecting the state at said position on the basis of a beat signal of the detected interference light.
Claim 2
Dependent Claim
27 words
An apparatus according to Claim 1, wherein said light projecting means includes scanning means for relatively scanning a surface to be inspected with the first light beam.
Claim 3
Dependent Claim
110 words
An inspection apparatus based on a heterodyne method, comprising: light producing means for producing a first light beam having a first wavelength, and a second light beam having a second wavelength different from the first wavelength; scanning means for deflecting at least the first light beam to optically scan a surface to be inspected; detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered from a position on the surface being scanned with the first light beam; and signal processing means for inspecting the state of the surface on the basis of a beat signal of the detected interference light.
Claim 4
Dependent Claim
18 words
An apparatus according to Claim 3, wherein the first and second light beams have different states of polarization.
Claim 5
Dependent Claim
29 words
An apparatus according to Claim 2 or 3, further comprising a lens system for imaging a scan region on said surface upon a detection surface of said detecting means.
Claim 6
Dependent Claim
26 words
An apparatus according to Claim 1 or 3, wherein the second light beam is projected on the same position being irradiated with the first light beam.
Claim 7
Dependent Claim
61 words
An apparatus according to Claim 6, wherein the second light beam is projected on the same position being irradiated with the the first light beam, in a direction different from the direction of projection of the first light beam, to cause heterodyne interference of zero-th order diffraction light of the second light component and scattered light of the first light beam.
Claim 8
Dependent Claim
30 words
An apparatus according to Claim 6 or 7, wherein the first light beam and the second light beam constitute a single light beam which is projected on the same position.
Claim 9
Dependent Claim
56 words
An apparatus according to Claim 8, wherein the second light beam and the light scattered in response to the projection of the first light beam upon upon said position to be inspected and scattered in a direction along the path of projection of the first light beam upon said position, are caused to produce heterodyne interference.
Claim 10
Dependent Claim
41 words
An apparatus according to Claim 1 or 3, wherein the second light beam is not projected to said position and wherein the second light beam and the scattered light attributable to the first light beam are caused to produce heterodyne interference.
Claim 11
Dependent Claim
56 words
An apparatus according to Claim 10, wherein the second light beam and the light scattered in response to the projection of the first light beam upon upon said position to be inspected and scattered in a direction along the path of projection of the first light beam upon said position, are caused to produce heterodyne interference.
Claim 12
Dependent Claim
30 words
An apparatus according to Claim 1 or 3, wherein said light producing means produces a single light beam in which the first and second light beams are superposed one another.
Claim 13
Dependent Claim
21 words
An apparatus according to Claim 1 or 3, wherein said light producing means produces the first and second light beams separately.
Claim 14
Dependent Claim
39 words
An apparatus according to Claim 1 or 3, wherein the first state of polarization is linear polarization in a predetermined direction and wherein the second state of polarization is linear polarization in a direction perpendicular to said predetermined direction.
Claim 15
Dependent Claim
42 words
An apparatus according to Claim 1 or 3, wherein the first state of polarization is circular polarization in a predetermined rotational direction and wherein the second state of polarization is circular polarization in a rotational direction countering to said predetermined rotational direction.
Claim 16
Dependent Claim
22 words
An apparatus according to Claim 1 or 3, wherein said signal processing means includes means for counting waves of the beat signal.
Claim 17
Dependent Claim
64 words
An apparatus according to Claim 1 or 3, further comprising oscillating means for generating a high-frequency signal of a frequency different from that of the beat signal of the detected interference light, and multiplying means for mutually multiplying the high-frequency signal and the beat signal, and wherein the state of said position being inspected is determined on the basis of the result of multiplication.
Claim 18
Dependent Claim
18 words
An apparatus according to Claim 1 or 3, wherein said light producing means includes a laser light source.
Claim 19
Dependent Claim
24 words
An apparatus according to Claim 2 or 3, wherein the surface to be inspected is an original on which a circuit pattern is formed.
Claim 20
Dependent Claim
26 words
An apparatus according to Claim 2 or 3, wherein the surface to be inspected is a wafer onto which a circuit pattern is to be transferred.
Claim 21
Dependent Claim
182 words
An inspection apparatus based on a heterodyne method, comprising: first light producing means for producing a first light beam having a first wavelength, and a second light beam having a second wavelength different from the first wavelength; second light producing means for producing a third light beam having a third wavelength, and a fourth light beam having a fourth wavelength different from the third wavelength; light projecting means for projecting at least the first and third light beams to a position of inspection; first detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered at said position as a result of projection of the the first light beam; second detecting means for detecting heterodyne interference light produced on the basis of the fourth light beam and the light scattered at said position as a result of projection of the third light beam; and signal processing means for inspecting the state at said position on the basis of beat signals of the detected interference lights, detected by said first and second detecting means.
Claim 22
Dependent Claim
31 words
An apparatus according to Claim 21, wherein the first and second light beams have different states of polarization and wherein the third and fourth light beams have different states of polarization.
Claim 23
Dependent Claim
62 words
An apparatus according to Claim 21, further comprising oscillating means for generating a high-frequency signal of a frequency different from that of the beat signal of the detected interference light, and multiplying means for mutually multiplying the high-frequency signal and the beat signal, and wherein the state of said position being inspected is determined on the basis of the result of multiplication.
Claim 24
Dependent Claim
163 words
An inspection apparatus based on a heterodyne method, comprising: light producing means for producing a first light beam having a first wavelength, and a second light beam having a second wavelength different from the first wavelength; light projecting means for projecting at least the first light beam to a position of inspection; first detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered from said position in a first direction as a result of projection of the first light beam; second detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered from said position in a second direction, different from the first direction, as a result of projection of the first light beam; and signal processing means for inspecting the state at said position on the basis of beat signals of the detected interference lights, detected by said first and second detecting means.
Claim 25
Dependent Claim
18 words
An apparatus according to Claim 24, wherein the first and second light beams have different states of polarization.
Claim 26
Dependent Claim
62 words
An apparatus according to Claim 24, further comprising oscillating means for generating a high-frequency signal of a frequency different from that of the beat signal of the detected interference light, and multiplying means for mutually multiplying the high-frequency signal and the beat signal, and wherein the state of said position being inspected is determined on the basis of the result of multiplication.
Claim 27
Dependent Claim
141 words
An inspection apparatus based on a heterodyne method, comprising: light producing means for producing a first light beam having a first wavelength, and a second light beam having a second wavelength different from the first wavelength; light projecting means for projecting at least the first light beam to a position of inspection; detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered from said position as a result of projection of the first light beam; and inspecting means including oscillating means for generating a high-frequency signal of a frequency different from that of the beat signal of the detected interference light, and multiplying means for mutually multiplying the high-frequency signal and the beat signal, said inspecting means inspecting the state of said position on the basis of the result of multiplication.
Claim 28
Dependent Claim
18 words
An apparatus according to Claim 27, wherein said oscillating means includes means for generating the high-frequency signal electrically.
Claim 29
Dependent Claim
18 words
An apparatus according to Claim 27, wherein said oscillating means includes means for generating the high-frequency signal optically.
Claim 30
Dependent Claim
18 words
An apparatus according to Claim 27, wherein the first and second light beams have different states of polarization.
Claim 31
Dependent Claim
176 words
An exposure system, comprising: an inspecting device for inspecting an original having an exposure pattern formed thereon; and an exposure device for printing on a workpiece the exposure pattern of the original, inspected by said inspecting device; wherein said inspecting device includes (a) light producing means for producing (i) a first light beam having a first state of polarization and a first wavelength and (ii) a second light beam having a second state of polarization, different from the first state of polarization, and a second wavelength, different from the first wavelength, (b) light projecting means for projecting at least the first light beam to a position on the original to be inspected, (c) detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered at said position and having its state of polarization changed by the scattering from the first state of polarization, and (d) signal processing means for inspecting the state at said position on the basis of a beat signal of the detected interference light.
Claim 32
Dependent Claim
152 words
An exposure system, comprising: an inspecting device for inspecting an original having an exposure pattern formed thereon; and an exposure device for printing on a workpiece the exposure pattern of the original, inspected by said inspecting device; wherein said inspecting device including (a) light producing means for producing first light beam having a first wavelength and a second light beam having a second wavelength, different from the first wavelength, (b) scanning means for deflecting at least the first light beam to optically scan the surface of the original, (c) detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered from a position on the surface of the original being scanned with the first light beam, and (d) signal processing means for inspecting the state of the surface of the original on the basis of a beat signal of the detected interference light.
Claim 33
Dependent Claim
178 words
A semiconductor device manufacturing system, comprising: an inspecting device for inspecting an original having an exposure pattern formed thereon; and an exposure device for printing on a wafer the exposure pattern of the original, inspected by said inspecting device; wherein said inspecting device includes (a) light producing means for producing (i) a first light beam having a first state of polarization and a first wavelength and (ii) a second light beam having a second state of polarization, different from the first state of polarization, and a second wavelength, different from the first wavelength, (b) light projecting means for projecting at least the first light beam to a position on the original to be inspected, (c) detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered at said position and having its state of polarization changed by the scattering from the first state of polarization, and (d) signal processing means for inspecting the state at said position on the basis of a beat signal of the detected interference light.
Claim 34
Dependent Claim
154 words
A semiconductor device manufacturing system, comprising: an inspecting device for inspecting an original having an exposure pattern formed thereon; and an exposure device for printing on a wafer the exposure pattern of the original, inspected by said inspecting device; wherein said inspecting device including (a) light producing means for producing first light beam having a first wavelength and a second light beam having a second wavelength, different from the first wavelength, (b) scanning means for deflecting at least the first light beam to optically scan the surface of the original, (c) detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered from a position on the surface of the original being scanned with the first light beam, and (d) signal processing means for inspecting the state of the surface of the original on the basis of a beat signal of the detected interference light.
Claim 35
Dependent Claim
168 words
A cleaning and inspecting system for an original, comprising: a cleaning device for cleaning the original; and an inspecting device for inspecting the original cleaned by said cleaning device; wherein said inspecting device includes (a) light producing means for producing (i) a first light beam having a first state of polarization and a first wavelength and (ii) a second light beam having a second state of polarization, different from the first state of polarization, and a second wavelength, different from the first wavelength, (b) light projecting means for projecting at least the first light beam to a position on the original to be inspected, (c) detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered at said position and having its state of polarization changed by the scattering from the first state of polarization, and (d) signal processing means for inspecting the state at said position on the basis of a beat signal of the detected interference light.
Claim 36
Dependent Claim
144 words
A cleaning and inspecting system for an original, comprising: a cleaning device for cleaning the original; and an inspecting device for inspecting the original cleaned by said cleaning device; wherein said inspecting device including (a) light producing means for producing first light beam having a first wavelength and a second light beam having a second wavelength, different from the first wavelength, (b) scanning means for deflecting at least the first light beam to optically scan the surface of the original, (c) detecting means for detecting heterodyne interference light produced on the basis of the second light beam and the light scattered from a position on the surface of the original being scanned with the first light beam, and (d) signal processing means for inspecting the state of the surface of the original on the basis of a beat signal of the detected interference light.
Claim 37
Dependent Claim
123 words
An inspection method based on a heterodyne method, comprising the steps of: producing (i) a first light beam having a first state of polarization and a first wavelength, and (ii) a second light beam having a second state of polarization, different from the first state of polarization, and a second wavelength, different from the first wavelength; projecting at least the first light beam to a position of inspection; detecting heterodyne interference light produced on the basis of the second light beam and the light scattered at said position and having its state of polarization changed by the scattering from the first state of polarization; and determining the state at said position on the basis of a beat signal of the detected interference light.
Claim 38
Dependent Claim
148 words
An exposure method, comprising the steps of: inspecting an original having an exposure pattern formed thereon; and printing on a workpiece the exposure pattern of the original inspected; wherein said inspecting step including (a) producing (i) a first light beam having a first state of polarization and a first wavelength, and (ii) a second light beam having a second state of polarization, different from the first state of polarization, and a second wavelength, different from the first wavelength, (b) projecting at least the first light beam to a position of inspection, (c) detecting heterodyne interference light produced on the basis of the second light beam and the light scattered at said position and having its state of polarization changed by the scattering from the first state of polarization, and (d) determining the state at said position on the basis of a beat signal of the detected interference light.
Claim 39
Dependent Claim
150 words
A semiconductor device manufacturing method, comprising the steps of: inspecting an original having an exposure pattern formed thereon; and printing on a wafer the exposure pattern of the original inspected; wherein said inspecting step including (a) producing (i) a first light beam having a first state of polarization and a first wavelength, and (ii) a second light beam having a second state of polarization, different from the first state of polarization, and a second wavelength, different from the first wavelength, (b) projecting at least the first light beam to a position of inspection, (c) detecting heterodyne interference light produced on the basis of the second light beam and the light scattered at said position and having its state of polarization changed by the scattering from the first state of polarization, and (d) determining the state at said position on the basis of a beat signal of the detected interference light.
Claim 40
Dependent Claim
145 words
A semiconductor device manufacturing method, comprising the steps of: inspecting a wafer; and printing a circuit pattern on the wafer inspected; wherein said inspecting step including (a) producing (i) a first light beam having a first state of polarization and a first wavelength, and (ii) a second light beam having a second state of polarization, different from the first state of polarization, and a second wavelength, different from the first wavelength, (b) projecting at least the first light beam to a position on the wafer to be inspected, (c) detecting heterodyne interference light produced on the basis of the second light beam and the light scattered at said position and having its state of polarization changed by the scattering from the first state of polarization, and (d) determining the state at said position on the basis of a beat signal of the detected interference light.
References Cited (Backward Citations)
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