US4877326A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for optical inspection of substrates
Assignee: KLA Corp
•
Filing: 1988-02-19
•
Granted: 1989-10-31
•
Expires: 2008-02-19
Abstract
Abstract Substrate inspection apparatus and methods, and illumination apparatus. The inspection apparatus and method includes memory for storing the desired features of the surface of the substrate, focussed illuminator for substantially uniformly illuminating a region of the surface of the substrate to be inspected. Additionally there is a sensor for imaging the region of the substrate illuminated by the illuminator, and a comparator responsive to the memory and sensor for comparing the imaged region of the substrate with the stored desired features of the substrate. The illumination apparatus is designed to provide substantially uniform focussed illumination along a narrow linear region. This apparatus includes first, second and third reflectors elliptically cylindrical in shape, each with its long axis substantially parallel to the long axes of each of the others. Fourth and fifth reflectors are also included with each being flat and mounted parallel to each other and at opposite ends of each of said first, second and third reflectors, and first, second and third linear light sources each mounted parallel to a corresponding one of said first, second and third reflectors with each of the light sources mounted so that it is at the first focus of the corresponding reflector and the illuminated linear region is at the second focus of each of the first, second and third reflectors.
Inventors
- 👤 Curt H. Chadwick
- 👤 Robert R. Sholes
- 👤 John D. Greene
- 👤 Francis D. Tucker, III
- 👤 Michael E. Fein
- 👤 P. C. Jann
- 👤 David J. Harvey
- 👤 William Bell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 00:16
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G01N21/95684; G01N21/8806; G01R; G01R31/00; G01R31/28; G01R31/302; G01R31/308; G01R31/311; G01N21/89; G01N21/8901; G01N2021/8908; G01N2021/95638
Claims Analysis
Total Claims: 61
Claim 1
Independent Claim
82 words
Inspection apparatus for inspecting surface features of a substrate comprising: memory means for storing the desired features of the surface of the substrate; focussed quasi-Lambertian illumination means for substantially uniformly illuminating a region of the surface of the substrate to be inspected; sensor means for imaging the region of the substrate illuminated by the illumination means; and comparison means responsive to the memory and sensor means for comparing the imaged region of the substrate with the stored desired features of the substrate.
Claim 2
Dependent Claim
82 words
Inspection apparatus for inspecting surface features of a substrate comprising: memory means for storing the desired features of the surface of the substrate; focussed quasi-Lambertian illumination means for substantially uniformly illuminating a region of the surface of the substrate to be inspected; sensor means for imaging the region of the substrate illuminated by the illumination means; and comparison means responsive to the memory and sensor means for comparing the imaged region of the substrate with the stored desired features of the substrate.
Claim 3
Dependent Claim
380 words
An inspection apparatus as in claim 1 wherein said illumination means includes: first and second reflector means elliptically cylindrical segments in shape, each with its long axis substantially parallel to the long axis of the other, and each being spaced-apart from the other along their closest edges to define a path through which the illuminated linear region can be viewed from above through said illumination means; third and fourth reflector means each being flat and mounted parallel to the other, at opposite ends of each of said first and second reflector means and substantially perpendicular to the long axis of each of said first and second reflector means; first and second linear light source means each mounted parallel to a corresponding one of said first and second reflector means, said first and second linear light source means each include a light source having a length that is substantially as long as the illuminated linear region is long, and that is parallel to a corresponding one of said first and second reflector means with each of the light source means mounted so that it is at the first focus of the corresponding reflector means and the illuminated linear region is at the second focus of each of the first and second reflector means; fifth reflector means elliptically cylindrical segments in shape with its long axis substantially parallel to the long axes of the first and second reflector means, being mounted above said first and second reflector means and away from the path through which the illuminated linear region can be viewed from above through said illumination means; beamsplitter means mounted in the path through which the illuminated linear region can be viewed from above through said illumination means, tilted to the optical viewing axis, and being positioned to reflect the focussed beam from the fifth reflector means to the illuminated linear region; and third linear light source means mounted parallel to said fifth reflector means to direct light onto substantially the entire surface of the fifth reflector means with the illuminated linear region at a first focus of the fifth reflector means and the illuminated linear region is at the second focus of the fifth reflector means with the beam from the fifth reflector means being reflected by the beamsplitter means.
Claim 4
Dependent Claim
171 words
An inspection apparatus as in claim 2 wherein: said first and second light source means are water cooled mercury capillary arc lamps; and said illumination means further includes: first and second optic filter means being removable and positionable between the illuminated linear region and each of the combinations of the first and second light source means and the first and second reflector means, respectively, for filtering the light delivered to the illuminated linear region from the combination of the first and second light source means and the first and second reflector means; third optic filter means being a visible light filter positioned on the side of the beamsplitter means that is away from the illuminated linear region and through which light from the illuminated linear region passes to the sensor means for passing only visible light to the sensor means; and lens means mounted on the side of the third optic filter means away from the beamsplitter means for focusing the light from the illuminated linear region onto the sensor means.
Claim 5
Dependent Claim
42 words
An inspection apparatus as in claim 2 wherein each of said first and second light source means include: an elongated lamp that is substantially as long as the illuminated linear region is long; and a transparent jacket means for surrounding said lamp.
Claim 6
Dependent Claim
24 words
An inspection apparatus as in claim 4 wherein said transparent jacket means is optically coated to filter the light emitted by the enclosed lamp.
Claim 7
Dependent Claim
29 words
An inspection apparatus as in claim 4 wherein said transparent jacket means forms a chamber around said lamp to provide a conduit for water cooling of the enclosed lamp.
Claim 8
Dependent Claim
43 words
An inspection apparatus as in claim 2 wherein said first and second reflector means include a wavelength-selective coating to cause light of selected wavelengths to be reflected and light of other wavelengths to be transmitted to reduce the heat loading of the substrate.
Claim 9
Dependent Claim
55 words
An inspection apparatus as in claim 1 wherein said illumination means includes a slit assembly means disposed to be immediately above said illuminated linear region for reducing the amount of light reflected from regions of the substrate into the sensor means that are not in the imaging region of the substrate by the sensor means.
Claim 10
Dependent Claim
37 words
An inspection apparatus as in claim 8 wherein said slit assembly means includes an integral air bearing means for causing the slit assembly means to fly at substantially a uniform height above the surface of the substrate.
Claim 11
Dependent Claim
144 words
An inspection apparatus as in claim 8 further including: a fixed mounting surface to which said sensor means is mounted; first mounting means for mounting said illumination means to said surface directly below said sensor means, said first mounting means disposed to permit movement of said illumination means only in the vertical direction with respect to the surface of the substrate to be inspected to maintain a relatively fixed distance between the illumination means and the surface of the substrate; and second mounting means for mounting said slit assembly means to said surface directly below said illumination means, said second mounting means disposed to permit movement of said slit assembly means only in the vertical direction with respect to the surface of the substrate to be inspected to maintain a relatively fixed distance between the slit assembly means and the surface of the substrate.
Claim 12
Dependent Claim
64 words
An inspection apparatus as in claim 1 wherein said illumination means includes: high volume air source means for providing a source of controlled direction moving air; and ducting means for directing said moving air through the illumination means to minimize the Schlieren effects within the illumination means in the optical path between the substantially uniformly illuminated region of the substrate and the sensor means.
Claim 13
Dependent Claim
15 words
Inspection apparatus as in claim 1 wherein said sensor means is a TDI sensor means.
Claim 14
Dependent Claim
20 words
Inspection apparatus as in claim 12 wherein said TDI sensor means is a two dimensional charge-coupled device light sensing array.
Claim 15
Dependent Claim
47 words
Inspection apparatus as in claim 12 wherein said TDI sensor means has at least two rows of light sensitive areas in a first direction know as the TDI dimension and at least one column of light sensitive areas in a second direction know as the multiplexing dimension.
Claim 16
Dependent Claim
24 words
Inspection apparatus as in claim 14 wherein said TDI sensor means includes at least one tap at evenly spaced intervals in the multiplexing dimension.
Claim 17
Dependent Claim
81 words
Inspection apparatus for inspecting surface features of a substrate comprising: memory means for storing the desired features of the surface of the substrate; illumination means for substantially uniformly illuminating a region of the surface of the substrate to be inspected; TDI sensor means for imaging the region of the substrate illuminated by the illumination means; and comparison means responsive to the memory and sensor means for comparing the imaged region of the substrate with the stored desired features of the substrate.
Claim 18
Dependent Claim
81 words
Inspection apparatus for inspecting surface features of a substrate comprising: memory means for storing the desired features of the surface of the substrate; illumination means for substantially uniformly illuminating a region of the surface of the substrate to be inspected; TDI sensor means for imaging the region of the substrate illuminated by the illumination means; and comparison means responsive to the memory and sensor means for comparing the imaged region of the substrate with the stored desired features of the substrate.
Claim 19
Dependent Claim
160 words
An inspection apparatus as in claim 16 wherein said illumination means includes: first and second reflector means elliptically cylindrical segments in shape, each with its long axis substantially parallel to the long axis of the other, and each being spaced-apart from the other along their closest edges to define a path through which the illuminated linear region can be viewed from above though said illumination means; third and fourth reflector means each being flat and mounted parallel to the other, at opposite ends of each of said first and second reflector means and substantially perpendicular to the long axis of each of said first and second reflector means; and first and second linear light source means each mounted parallel to a corresponding one of said first and second reflector means to direct light onto substantially the entire surface of the corresponding reflector means with the illuminated linear region at one focus of each of the first and second reflector means.
Claim 20
Dependent Claim
58 words
An inspection apparatus as in claim 17 wherein said first and second linear light source means each include a fiber optic bundle with exit ends that are narrow in height and substantially as wide as the illuminated linear region and an incoherent light source disposed to illuminate the entrance ends of said first and second fiber optic bundle.
Claim 21
Dependent Claim
91 words
An inspection apparatus as in claim 17 wherein said first and second linear light source means each include a light source having a length that is substantially as long as the illuminated linear region is long, and that is parallel to a corresponding one of said first and second reflector means with each of the light source means mounted so that it is at the first focus of the corresponding reflector means and the illuminated linear region is at the second focus of each of the first and second reflector means.
Claim 22
Dependent Claim
182 words
An inspection apparatus as in claim 19 wherein said illumination means further includes: fifth reflector means elliptically cylindrical segments in shape with its long axis substantially parallel to the long axes of the first and second reflector means, being mounted above said first and second reflector means and away from the path through which the illuminated linear region can be viewed from above through said illumination means; beamsplitter means mounted in the path through which the illuminated linear region can be viewed from above through said illumination means, tilted to the optical viewing axis, and being positioned to reflect the focussed beam from the fifth reflector means to the illuminated linear region; and third linear light source means mounted parallel to said fifth reflector means to direct light onto substantially the entire surface of the fifth reflector means with said third linear light source means at a first focus of the fifth reflector means and the illuminated linear region at the second focus of the fifth reflector means with the beam from the fifth reflector means being reflected by the beamsplitter means.
Claim 23
Dependent Claim
171 words
An inspection apparatus as in claim 20 wherein: said first and second light source means are water cooled mercury capillary arc lamps; and said illumination means further includes: first and second optic filter means being removable and positionable between the illuminated linear region and each of the combinations of the first and second light source means and the first and second reflector means, respectively, for filtering the light delivered to the illuminated linear region from the combination of the first and second light source means and the first and second reflector means; third optic filter means being a visible light filter positioned on the side of the beamsplitter means that is away from the illuminated linear region and through which light from the illuminated linear region passes to the sensor means for passing only visible light to the sensor means; and lens means mounted on the side of the third optic filter means away from the beamsplitter means for focusing the light from the illuminated linear region onto the sensor means.
Claim 24
Dependent Claim
42 words
An inspection apparatus as in claim 17 wherein each of said first and second light source means include: an elongated lamp that is substantially as long as the illuminated linear region is long; and a transparent jacket means for surrounding said lamp.
Claim 25
Dependent Claim
24 words
An inspection apparatus as in claim 22 wherein said transparent jacket means is optically coated to filter the light emitted by the enclosed lamp.
Claim 26
Dependent Claim
29 words
An inspection apparatus as in claim 22 wherein said transparent jacket means forms a chamber around said lamp to provide a conduit for water cooling of the enclosed lamp.
Claim 27
Dependent Claim
43 words
An inspection apparatus as in claim 17 wherein said first and second reflector means include a wavelength-selective coating to cause light of selected wavelengths to be reflected and light of other wavelengths to be transmitted to reduce the heat loading of the substrate.
Claim 28
Dependent Claim
55 words
An inspection apparatus as in claim 16 wherein said illumination means includes a slit assembly means disposed to be immediately above said illuminated linear region for reducing the amount of light reflected from regions of the substrate into the sensor means that are not in the imaging region of the substrate by the sensor means.
Claim 29
Dependent Claim
37 words
An inspection apparatus as in claim 26 wherein said slit assembly means includes an integral air bearing means for causing the slit assembly means to fly at substantially a uniform height above the surface of the substrate.
Claim 30
Dependent Claim
144 words
An inspection apparatus as in claim 26 further including: a fixed mounting surface to which said sensor means is mounted; first mounting means for mounting said illumination means to said surface directly below said sensor means, said first mounting means disposed to permit movement of said illumination means only in the vertical direction with respect to the surface of the substrate to be inspected to maintain a relatively fixed distance between the illumination means and the surface of the substrate; and second mounting means for mounting said slit assembly means to said surface directly below said illumination means, said second mounting means disposed to permit movement of said slit assembly means only in the vertical direction with respect to the surface of the substrate to be inspected to maintain a relatively fixed distance between the slit assembly means and the surface of the substrate.
Claim 31
Dependent Claim
64 words
An inspection apparatus as in claim 16 wherein said illumination means includes: high volume air source means for providing a source of controlled direction moving air; and ducting means for directing said moving air through the illumination means to minimize the Schlieren effects within the illumination means in the optical path between the substantially uniformly illuminated region of the substrate and the sensor means.
Claim 32
Dependent Claim
20 words
Inspection apparatus as in claim 16 wherein said TDI sensor means is a two dimensional charge-coupled device light sensing array.
Claim 33
Dependent Claim
47 words
Inspection apparatus as in claim 16 wherein said TDI sensor means has at least two rows of light sensitive areas in a first direction know as the TDI dimension and at least one column of light sensitive areas in a second direction know as the multiplexing dimension.
Claim 34
Dependent Claim
24 words
Inspection apparatus as in claim 31 wherein said TDI sensor means includes at least one tap at evenly spaced intervals in the multiplexing dimension.
Claim 35
Independent Claim
74 words
A method for inspecting surface features of a substrate, said method comprising the steps of: a. storing the desired features of the surface of the substrate; b. substantially uniformly illuminating a region of the surface of the substrate to be inspected with focussed quasi-Lambertian illumination; c. imaging the region of the substrate illuminated by the illumination means; and d. comparing the imaged region of the substrate with the stored desired features of the substrate.
Claim 36
Independent Claim
74 words
A method for inspecting surface features of a substrate, said method comprising the steps of: a. storing the desired features of the surface of the substrate; b. substantially uniformly illuminating a region of the surface of the substrate to be inspected with focussed quasi-Lambertian illumination; c. imaging the region of the substrate illuminated by the illumination means; and d. comparing the imaged region of the substrate with the stored desired features of the substrate.
Claim 37
Dependent Claim
36 words
A method as in claim 33 wherein step b. includes the step of: e. illuminating a region on the surface of the substrate through a narrow slit disposed above the surface and in close proximity thereto.
Claim 38
Dependent Claim
30 words
A method as in claim 33 wherein said method further includes the step of: f. directing air flow passed the illuminated region to minimize the Schlieren effect in step c.
Claim 39
Dependent Claim
44 words
A method as in claim 33 wherein said method further includes the step of: g. moving the illumination means vertically with respect to the surface to be inspected to maintain a relatively constant spacing therebetween to maintain the surface in focus during step c.
Claim 40
Dependent Claim
45 words
A method as in claim 33 wherein step b. includes the steps of: h. illuminating the surface of the substrate with short-wave incoherent light; and i. imaging the surface of the substrate with light of a longer wave length than the light of step h.
Claim 41
Dependent Claim
64 words
A method as in claim 33 further including the steps of: i. performing steps a. through d. with the illumination of step b. being short-wave incoherent light and imaging the substrate with light of a longer wave length than the light of the illumination of the substrate; and j. performing steps a. through d. with the illumination of step b. being quasi Lambertian illumination.
Claim 42
Independent Claim
74 words
A method for inspecting surface features of a substrate, said method comprising the steps of: a. storing the desired features of the surface of the substrate; b. substantially uniformly illuminating a region of the surface of the substrate to be inspected; c. imaging the region of the substrate illuminated by the illumination means with TDI sensor means; and d. comparing the imaged region of the substrate with the stored desired features of the substrate.
Claim 43
Independent Claim
74 words
A method for inspecting surface features of a substrate, said method comprising the steps of: a. storing the desired features of the surface of the substrate; b. substantially uniformly illuminating a region of the surface of the substrate to be inspected; c. imaging the region of the substrate illuminated by the illumination means with TDI sensor means; and d. comparing the imaged region of the substrate with the stored desired features of the substrate.
Claim 44
Dependent Claim
36 words
A method as in claim 39 wherein step b. includes the step of: e. illuminating a region on the surface of the substrate through a narrow slit disposed above the surface and in close proximity thereto.
Claim 45
Dependent Claim
30 words
A method as is claim 39 wherein said method further includes the step of: f. directing air flow passed the illuminated region to minimize the Schlieren effect in step c.
Claim 46
Dependent Claim
44 words
A method as in claim 39 wherein said method further includes the step of: g. moving the illumination means vertically with respect to the surface to be inspected to maintain a relatively constant spacing therebetween to maintain the surface in focus during step c.
Claim 47
Dependent Claim
44 words
A method as in claim 39 wherein step b. includes the steps of: h. illuminating the surface of the substrate with short-wave incoherent light; and i. imaging the surface of the substrate with light of a longer wavelength than the light of step h.
Claim 48
Dependent Claim
64 words
A method as in claim 39 further including the steps of: i. performing steps a. through d. with the illumination of step b. being short-wave incoherent light and imaging the substrate with light of a longer wave length than the light of the illumination of the substrate; and j. performing steps a. through d. with the illumination of step b. being quasi Lambertian illumination.
Claim 49
Dependent Claim
162 words
Illumination apparatus for substantial uniform focussed illumination along a narrow linear region comprising: first and second reflector means elliptically cylindrical segments in shape, each with its long axis substantially parallel to the long axes of the other, and each being spaced-apart from the other along their closest edges to define a path through which the illuminated linear region can be viewed from above through said illumination apparatus; third and fourth reflector means each being flat and mounted parallel to the other and at opposite ends of each of said first and second reflector means and substantially perpendicular to the long axis of each of said first and second reflector means; and first and second linear light source means each mounted parallel to a corresponding one of said first and second reflector means to direct light onto substantially the entire surface of the corresponding reflector means with the illuminated linear region at one focus of each of the first and second reflector means.
Claim 50
Dependent Claim
162 words
Illumination apparatus for substantial uniform focussed illumination along a narrow linear region comprising: first and second reflector means elliptically cylindrical segments in shape, each with its long axis substantially parallel to the long axes of the other, and each being spaced-apart from the other along their closest edges to define a path through which the illuminated linear region can be viewed from above through said illumination apparatus; third and fourth reflector means each being flat and mounted parallel to the other and at opposite ends of each of said first and second reflector means and substantially perpendicular to the long axis of each of said first and second reflector means; and first and second linear light source means each mounted parallel to a corresponding one of said first and second reflector means to direct light onto substantially the entire surface of the corresponding reflector means with the illuminated linear region at one focus of each of the first and second reflector means.
Claim 51
Dependent Claim
57 words
An inspection apparatus as in claim 45 wherein said first and second linear light source means each include fiber optic bundle with exit ends that are narrow in height and substantially as wide as the illuminated linear region and an incoherent light source disposed to illuminate the entrance ends of said first and second fiber optic bundle.
Claim 52
Dependent Claim
90 words
Illumination apparatus as in claim 45 wherein said first and second linear light source means each include a light source having a length that is substantially as long as the illuminated linear region is long, and that is parallel to a corresponding one of said first and second reflector means with each of the light source means mounted so that it is at the first focus of the corresponding reflector means and the illuminated linear region is at the second focus of each of the first and second reflector means.
Claim 53
Dependent Claim
176 words
Illumination apparatus as in claim 47 further includes: fifth reflector means elliptically cylindrical segments in shape with its long axis substantially parallel to the long axes of the first and second reflector means, being mounted above said first and second reflector means and away from the path through which the illuminated linear region can be viewed from above through said illumination apparatus; beamsplitter means mounted in the path through which the illuminated linear region can be viewed from above through said illumination apparatus, tilted to the optical viewing axis, and being positioned to reflect the focussed beam from the fifth reflector means to the illuminated linear region; and third linear light source means mounted parallel to said fifth reflector means to direct light onto substantially the entire surface of the fifth reflector means with said third linear light source at a first focus of the fifth reflector means and the illuminated linear region at the second focus of the fifth reflector means with the beam from the fifth reflector means being reflected by the beamsplitter means.
Claim 54
Dependent Claim
166 words
Illumination apparatus as in claim 48 wherein: said first and second light source means are water cooled mercury capillary arc lamps; and said illumination apparatus further includes: first and second optic filter means being removable and positionable between the illuminated linear region and each of the combinations of the first and second light source means and the first and second reflector means, respectively, for filtering the light delivered to the illuminated linear region from the combination of the first and second light source means and the first and second reflector means; third optic filter means being a visible light filter position on the side of the beamsplitter means that is away from the illuminated linear region and through which light from the illuminated linear region passes to the sensor means for passing only visible light to the sensor means; and lens means mounted on the side of the third optic filter means away from the beamsplitter means for focusing the light from the illuminated linear region.
Claim 55
Dependent Claim
41 words
Illumination apparatus as in claim 45 wherein each of said first and second light source means include: an elongated lamp that is substantially as long as the illuminated linear region is long: and a transparent jacket means for surrounding said lamp.
Claim 56
Dependent Claim
23 words
Illumination apparatus as in claim 50 wherein said transparent jacket means is optically coated to filter the light emitted by the enclosed lamp.
Claim 57
Dependent Claim
28 words
Illumination apparatus as in claim 50 wherein said transparent jacket means forms a chamber around said lamp to provide a conduit for water cooling of the enclosed lamp.
Claim 58
Dependent Claim
21 words
Illumination apparatus as in claim 45 further includes a slit assembly means disposed to be immediately above said illuminated linear region.
Claim 59
Dependent Claim
37 words
Illumination apparatus as in claim 53 wherein said slit assembly means includes an integral air bearing means for causing the slit assembly means to fly at substantially a uniform height above a surface below the illumination apparatus.
Claim 60
Dependent Claim
46 words
Illumination apparatus as in claim 45 wherein said first and second reflector means include a wavelength-selective coating to cause light of elected wavelengths to be reflected and light of other wavelengths to be transmitted to reduce the heat loading of a surface below the illumination apparatus.
Claim 61
Dependent Claim
55 words
Illumination apparatus as in claim 45 further includes: high volume air source means for providing a source of controlled direction moving air; and ducting means for directing said moving air through the illumination apparatus to minimize the Schlieren effects within the illumination apparatus in the region between the substantially uniformly illuminated region and the sensor.
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| 3.5 Years (Year 4) | 1992-10-30 | 1993-05-01 | 1993-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-30 | 1997-05-01 | 1997-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-30 | 2001-05-01 | 2001-10-31 | $7700.00 | Window Closed / Lapsed |