Patent US4758094A successfully refreshed from Google Patents.
US4758094A
Expired / Lapsed
US
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Process and apparatus for in-situ qualification of master patterns used in patterning systems
Assignee: KLA Corp
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Filing: 1987-05-15
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Granted: 1988-07-19
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Expires: 2007-05-15
Abstract
Abstract A process and apparatus for qualifying a reticle, master pattern, or the like, in-situ as it is used in a system for photolithographically creating an image on a substrate, including the steps of coating a transparent substrate with a layer of transparent photoresist material, placing the coated substrate with a layer of transparent photoresist material, placing the coated substrate on a substrate supporting means, using a source of illumination in combination with a reticle, or master pattern, to create an image of the reticle, or master pattern, on the substrate, thereby exposing the photo resist coated on the surface thereof, removing the substrate from the supporting means, developing the exposed photoresist to produce a transparent patterned mask on the surface of the substrate, said patterned mask corresponding to the pattern on the reticle, or master pattern, and, in combination with the substrate, forming a monitor object, inspecting the monitor object by passing light through both the transparent masked and transparent unmasked areas of the substrate to detect defects, and using the detected defects as a measure of the quality of the reticle or master pattern.
Inventors
- 👤 Tim S. Wihl
- 👤 Frank D. Yasher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:28
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/68; G03F1/82; G03F1/84
Claims Analysis
Total Claims: 56
Claim 1
Independent Claim
189 words
A process for qualifying a reticle, master pattern, or the like, in-situ as it is used in a system for photolithographically creating an image on a substrate, such system normally including a source of illumination, a reticle or master pattern, and a substrate supporting means, comprising the steps of: coating a transparent substrate with a layer of transparent photoresist material; placing the coated substrate on the substrate supporting means; using the source of illumination in combination with the reticle, or master pattern, to create an image of the reticle, or master pattern, on the substrate, thereby exposing the photoresist coated on the surface thereof; removing the substrate from the supporting means; developing the exposed photoresist to produce a transparent patterned mask on the surface of the substrate, said patterned mask corresponding to the pattern on the reticle, or master pattern, and in combination with the substrate, forming a monitor object; inspecting the monitor object by passing light through both the transparent masked and transparent unmasked areas of the substrate to detect defects; and using the detected defects as a measure of the quality of the reticle or master pattern.
Claim 2
Dependent Claim
189 words
A process for qualifying a reticle, master pattern, or the like, in-situ as it is used in a system for photolithographically creating an image on a substrate, such system normally including a source of illumination, a reticle or master pattern, and a substrate supporting means, comprising the steps of: coating a transparent substrate with a layer of transparent photoresist material; placing the coated substrate on the substrate supporting means; using the source of illumination in combination with the reticle, or master pattern, to create an image of the reticle, or master pattern, on the substrate, thereby exposing the photoresist coated on the surface thereof; removing the substrate from the supporting means; developing the exposed photoresist to produce a transparent patterned mask on the surface of the substrate, said patterned mask corresponding to the pattern on the reticle, or master pattern, and in combination with the substrate, forming a monitor object; inspecting the monitor object by passing light through both the transparent masked and transparent unmasked areas of the substrate to detect defects; and using the detected defects as a measure of the quality of the reticle or master pattern.
Claim 3
Dependent Claim
58 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 1 and further including the step of providing an opaque border around at least a substantial portion of the perimeter of the substrate before it is coated with the photoresist material, said border being used to facilitate automatic handling of the monitor object.
Claim 4
Dependent Claim
55 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 2 and further including the step of providing the substrate with a coating that is transmissive of predetermined wavelengths used for inspection purposes and is reflective of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 5
Dependent Claim
55 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 2 and further including the step of providing the substrate with a coating that is transmissive of predetermined wavelengths used for inspection purposes and is absorptive of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 6
Dependent Claim
45 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 2 wherein the substrate is transmissive of predetermined wavelengths used for inspection purposes and is absorptive of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 7
Dependent Claim
55 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 1 and further including the step of providing the substrate with a coating that is transmissive of predetermined wavelengths used for inspection purposes and is reflective of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 8
Dependent Claim
45 words
A process for qualifying a reticle, master pattern, or the like as recited in claim 6 wherein the substrate is transmissive of predetermined wavelengths used for inspection purposes and is absorptive of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 9
Dependent Claim
45 words
A process for qualifying a reticle, master pattern, or the like as recited in claim 1 wherein the substrate is transmissive of predetermined wavelengths used for inspection purposes and is absorptive of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 10
Dependent Claim
55 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 8 and further including the step of providing the substrate with a coating that is transmissive of predetermined wavelengths used for inspection purposes and is reflective of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 11
Dependent Claim
58 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 9 and further including the step of providing an opaque border around at least a substantial portion of the perimeter of the substrate before it is coated with the photoresist material, said border being used to facilitate automatic handling of the monitor object.
Claim 12
Dependent Claim
37 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 1 wherein the transparent substrate is made of a material selected from the group of materials including glass, quartz, sapphire and borosilicate.
Claim 13
Dependent Claim
41 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 1 wherein the substrate is transparent to predetermined wavelengths of light used to inspect the monitor object and is opaque to other predetermined wavelengths of light.
Claim 14
Dependent Claim
42 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 12 wherein the photoresist material is transparent to predetermined wavelengths of light used to inspect the monitor object and is opaque to other predetermined wavelengths of light.
Claim 15
Dependent Claim
42 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 1 wherein the photoresist material is transparent to predetermind wavelengths of light used to inspect the monitor object and is opaque to other predetermined wavelengths of light.
Claim 16
Dependent Claim
53 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 1 wherein during inspection of the monitor object light is passed through the masked and unmasked areas of the substrate in a manner so as to create an image having bands signifying the edges of the masked areas.
Claim 17
Dependent Claim
33 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 15 wherein the bands created by the monitor object are compared to corresponding dark bands of a reference.
Claim 18
Dependent Claim
28 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 15 wherein said bands are created using darkfield illumination of the monitor object.
Claim 19
Dependent Claim
28 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 15 wherein said bands are created using brightfield illumination of the monitor object.
Claim 20
Dependent Claim
40 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 15 wherein the inspection is made using a sampling system having a pixel size approximately equal to or smaller than the width of a band.
Claim 21
Dependent Claim
37 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 1 wherein an optical system having a predetermined numerical aperture is used to pass light through the monitor object during inspection thereof.
Claim 22
Dependent Claim
53 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 20 wherein said predetermined numerical aperture is large enough to provide an image having a high contrast band and small enough that the optical system has sufficient depth of field to accommodate the thickness of the patterned mask.
Claim 23
Dependent Claim
40 words
A process for qualifying a reticle, master pattern, or the like, as recited in claim 21 wherein the inspection is made using a sampling system having a pixel size approximately equal to or smaller than the width of a band.
Claim 24
Dependent Claim
142 words
A monitor object for use in qualifying a particular recticle, master pattern, or the like, in-situ as it is used in a system for photolithographically creating an image on a product object, comprising: a substrate which is transparent to predetermined visible wavelenths of light and has physical dimensions generally corresponding to those of said particular product object to be qualified using said monitor object; and a coating of transparent photoresist material covering at least one surface of substrate, said coating being used to produce a transparent patterned mask on the surface of said substrate when photolithographically exposed to illumination passed through the reticle or master pattern, whereby light may be passed through the transparent masked and transparent unmasked areas of the sustrate to create an image which may be compared to a reference to detect defects in said reticle or master pattern.
Claim 25
Dependent Claim
142 words
A monitor object for use in qualifying a particular recticle, master pattern, or the like, in-situ as it is used in a system for photolithographically creating an image on a product object, comprising: a substrate which is transparent to predetermined visible wavelenths of light and has physical dimensions generally corresponding to those of said particular product object to be qualified using said monitor object; and a coating of transparent photoresist material covering at least one surface of substrate, said coating being used to produce a transparent patterned mask on the surface of said substrate when photolithographically exposed to illumination passed through the reticle or master pattern, whereby light may be passed through the transparent masked and transparent unmasked areas of the sustrate to create an image which may be compared to a reference to detect defects in said reticle or master pattern.
Claim 26
Dependent Claim
37 words
A monitor object as recited in claim 23 and further comprising means forming an opaque substrate border around at least a portion of the perimeter of said substrate for facilitating the automatic handling of the monitor object.
Claim 27
Dependent Claim
43 words
A monitor object as recited in claim 24 and further comprising a coating on said substrate that is transmisssive of predetermined wavelengths used for inspection purposes and is reflective of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 28
Dependent Claim
43 words
A monitor object as recited in claim 24 and further comprising a coating on said substrate that is transmissive of predetermined wavelengths used for inspection purposes and is absorptive of other predetermined wavelengths used for automatic handling and/or focussing of the monitoring object.
Claim 29
Dependent Claim
38 words
A monitor object as recited in claim 24 wherein the substrate is transmissive of predetermined wavelengths used for inspection purposes and is absorptive of other predetermined wavelengths used for automatic handling and or focussing of the monitor object.
Claim 30
Dependent Claim
40 words
A monitor object as recited in claim 23 and further comprising a coating that is transmissive of predetermined wavelengths used for inspection purposes and is reflective of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 31
Dependent Claim
37 words
A monitor object as recited in claim 28 wherein the substrate is transmissive of predetermined wavelengths used for inspection purposes and is absorptive of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 32
Dependent Claim
37 words
A monitor object as recited in claim 23 wherein the substrate is transmissive of predetermined wavelengths used for inspection purposes and is absorptive of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 33
Dependent Claim
40 words
A monitor object as recited in claim 30 and further comprising a coating that is transmissive of predetermined wavelengths used for inspection purposes and is reflective of other predetermined wavelengths used for automatic handling and/or focussing of the monitor object.
Claim 34
Dependent Claim
39 words
A monitor object as recited in claim 31 and further comprising means forming an opaque border around at least a portion of the perimeter of the substrate, said border being used to facilitate automatic handling of the monitor object.
Claim 35
Dependent Claim
29 words
A monitor object as recited in claim 23 wherein the transparent substrate is made of a material selected from the group of materials including glass, quartz, sapphire and borosilicate.
Claim 36
Dependent Claim
23 words
A monitor object as recited in claim 23 wherein the substrate is transparent to wavelengths of light used to inspect the monitor object.
Claim 37
Dependent Claim
24 words
A monitor object as recited in claim 34 wherein the photoresist material is transparent to wavelengths of light used to inspect the monitor object.
Claim 38
Dependent Claim
24 words
A monitor object as recited in claim 23 wherein the photoresist material is transparent to wavelengths of light used to inspect the monitor object.
Claim 39
Dependent Claim
68 words
A process for inspecting an object consisting of a transparent substrate, having formed thereon regions of transparent material, for the purpose of determining that the boundaries of the regions are accurately defined, comprising the steps of: passing light through the object to form an image thereof wherein the boundaries of the regions appear as bands; and comparing the bands to a reference to locate variances exceeding predetermined criteria.
Claim 40
Dependent Claim
68 words
A process for inspecting an object consisting of a transparent substrate, having formed thereon regions of transparent material, for the purpose of determining that the boundaries of the regions are accurately defined, comprising the steps of: passing light through the object to form an image thereof wherein the boundaries of the regions appear as bands; and comparing the bands to a reference to locate variances exceeding predetermined criteria.
Claim 41
Dependent Claim
66 words
A process for inspecting an object as recited in claim 37 wherein the step of passing light through the object is accomplished by illuminating the object with a beam of light having a predetermined angle of convergence; collecting the light passing through the object and focussing it upon a detector to detect the level of light transmission of the object on a pixel by pixel basis.
Claim 42
Dependent Claim
43 words
A process for inspecting an object as recited in claim 37 wherein the step of comparing the bands to a reference includes the steps of identifying each pixel falling within the bands and comparing the level of light transmitted therethrough to a reference.
Claim 43
Dependent Claim
61 words
A process for inspecting an object as recited in claim 37 wherein the step of passing light through the object is accomplished using an image forming system having a numerical aperture large enough to provide an image having high contrast bands and small enough that the optical system has sufficient depth of field to accommodate the thickness of the transparent material.
Claim 44
Dependent Claim
41 words
A process for inspecting an object as recited in claim 40 wherein the detected level of light of each pixel is obtained using a sampling system having a pixel size approximately equal to or smaller than the width of a band.
Claim 45
Dependent Claim
69 words
A process for inspecting an object consisting of a transparent substrate, having formed thereon regions of transparent material, for the purpose of determining that the boundaries of the regions are accurately defined, comprising the steps of: passing light through the object to form an image thereof wherein the boundaries of the regions appear as bands; and comparing the bands to a reference to determine the accuracy of their definition.
Claim 46
Dependent Claim
69 words
A process for inspecting an object consisting of a transparent substrate, having formed thereon regions of transparent material, for the purpose of determining that the boundaries of the regions are accurately defined, comprising the steps of: passing light through the object to form an image thereof wherein the boundaries of the regions appear as bands; and comparing the bands to a reference to determine the accuracy of their definition.
Claim 47
Dependent Claim
66 words
A process for inspecting an object as recited in claim 42 wherein the step of passing light through the object is accomplished by illuminating the object with a beam of light having a predetermined angle of convergence; collecting the light passing through the object and focussing it upon a detector to detect the level of light transmission of the object on a pixel by pixel basis.
Claim 48
Dependent Claim
43 words
A process for inspecting an object as recited in claim 42 wherein the step of comparing the bands to a reference includes the steps of identifying each pixel falling within the bands and comparing the level of light transmitted therethrough to a reference.
Claim 49
Dependent Claim
61 words
A process for inspecting an object as recited in claim 42 wherein the step of passing light through the object is accomplished using an image forming system having a numerical aperture large enough to provide an image having high contrast bands and small enough that the optical system has sufficient depth of field to accommodate the thickness of the transparent material.
Claim 50
Dependent Claim
41 words
A process for inspecting an object as recited in claim 45 wherein the detected level of light of each pixel is obtained using a sampling system having a pixel size approximately equal to or smaller than the width of a band.
Claim 51
Dependent Claim
76 words
A process for inspecting an object consisting of a transparent substrate, having formed thereon regions of transparent material, for the purpose of determining that the boundaries of the regions are accurately defined, comprising the steps of: passing light through the object to form an image thereof wherein the boundaries of the regions appear as bands; and inspecting the image to determine whether or not a particular characteristic of the bands is consistent with a predetermined criteria.
Claim 52
Dependent Claim
76 words
A process for inspecting an object consisting of a transparent substrate, having formed thereon regions of transparent material, for the purpose of determining that the boundaries of the regions are accurately defined, comprising the steps of: passing light through the object to form an image thereof wherein the boundaries of the regions appear as bands; and inspecting the image to determine whether or not a particular characteristic of the bands is consistent with a predetermined criteria.
Claim 53
Dependent Claim
66 words
A process for inspecting an object as recited in claim 47 wherein the step of passing light through the object is accomplished by illuminating the object with a beam of light having a predetermined angle of convergence; collecting the light passing through the object and focussing it upon a detector to detect the level of light transmission of the object on a pixel by pixel basis.
Claim 54
Dependent Claim
43 words
A process for inspecting an object as recited in claim 47 wherein the step of comparing the bands to a reference includes the steps of identifying each pixel falling within the bands and comparing the level of light transmitted therethrough to a reference.
Claim 55
Dependent Claim
61 words
A process for inspecting an object as recited in claim 47 wherein the step of passing light through the object is accomplished using an image forming system having a numerical aperture large enough to provide an image having high contrast bands and small enough that the optical system has sufficient depth of field to accommodate the thickness of the transparent material.
Claim 56
Dependent Claim
41 words
A process for inspecting an object as recited in claim 50 wherein the detected level of light of each pixel is obtained using a sampling system having a pixel size approximately equal to or smaller than the width of a band.
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USPTO Annuity & Maintenance Windows
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| 3.5 Years (Year 4) | 1991-07-19 | 1992-01-18 | 1992-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-19 | 1996-01-18 | 1996-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-19 | 2000-01-18 | 2000-07-19 | $7700.00 | Window Closed / Lapsed |