US3955072A
Expired / Lapsed
US
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Apparatus for the automatic alignment of two superimposed objects for example a semiconductor wafer and a transparent mask
Assignee: Kasper Instruments Inc
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Filing: 1972-06-12
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Granted: 1976-05-04
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Expires: 1992-06-12
Abstract
Abstract An apparatus for automatically aligning a semiconductor wafer with a mask in the manufacture of integrated circuit devices is disclosed. The mask and wafer are each provided with alignment patterns, the alignment pattern on the wafer cooperating with the alignment pattern on the mask in a unique visual manner to signify alignment. A scanning mechanism is provided for automatically scanning the alignment pattern areas and producing output signals indicative of the relative positions of the alignment patterns on the wafer and mask. Logic circuitry is provided for operating in response to any misalignment represented by the scan output signals to compute formulae which are utilized to produce control signals for driving motor drive mechanisms to produce relative movement between the mask and wafer to bring them into alignment. Several separate alignment cycles are provided, if needed, for zeroing in on finalized alignment. A tolerance selection control circuit is provided for permitting a variation in final alignment tolerance.
Inventors
- 👤 Karl-Heinz Johannsmeier
- 👤 Paul E. Stoft
- 👤 Tor G. Larsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:51
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; G06; G06T; G06T1/00; G06T1/0014
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
378 words
A system for aligning two objects, a first one of said objects having first and second alignment patterns thereon, each of those alignment patterns comprising a first elongated bar and a second elongated bar at an angle to the first bar, a second one of said objects having corresponding first and second alignment patterns thereon, each of those alignment patterns comprising a first elongated bar and a second elongated bar at an angle to the first bar substantially equal to the angle between the first and second bars of each alignment pattern on the first object, the first and second bars of the first alignment pattern on the first object being arranged to be positioned parallel to and at a spaced preselected position relative to the first and second bars, respectively, of the corresponding first alignment pattern on the second object and the first and second bars of the second aligment pattern on the first object being arranged to be positioned parallel to and at a spaced preselected position relative to the first and second bars, respectively, of the corresponding second alignment pattern on the second object when the first and second objects are in alignment, said system comprising scanning means for scanning the first bars of each of the alignment patterns on the first and second objects and for scanning the second bars of each of the alignment patterns on the first and second objects, measurement means coupled to said scanning means for producing output signals indicative of the position of the first and second bars of each alignment pattern on the first object relative to the first and second bars, respectively, of the corresponding alignment pattern on the second object and proportional to the distance that the first and second bars of each alignment pattern on the first object are removed from the preselected position relative to the first and second bars, respectively, of the corresponding alignment pattern on the second object, and drive means responsive to those output signals for producing relative movement between the first and second objects to bring the first and second bars of each alignment pattern on the first object to the preselected position relative to the first and second bars, respectively, of the corresponding alignment pattern on the second object.
Claim 2
Independent Claim
378 words
A system for aligning two objects, a first one of said objects having first and second alignment patterns thereon, each of those alignment patterns comprising a first elongated bar and a second elongated bar at an angle to the first bar, a second one of said objects having corresponding first and second alignment patterns thereon, each of those alignment patterns comprising a first elongated bar and a second elongated bar at an angle to the first bar substantially equal to the angle between the first and second bars of each alignment pattern on the first object, the first and second bars of the first alignment pattern on the first object being arranged to be positioned parallel to and at a spaced preselected position relative to the first and second bars, respectively, of the corresponding first alignment pattern on the second object and the first and second bars of the second aligment pattern on the first object being arranged to be positioned parallel to and at a spaced preselected position relative to the first and second bars, respectively, of the corresponding second alignment pattern on the second object when the first and second objects are in alignment, said system comprising scanning means for scanning the first bars of each of the alignment patterns on the first and second objects and for scanning the second bars of each of the alignment patterns on the first and second objects, measurement means coupled to said scanning means for producing output signals indicative of the position of the first and second bars of each alignment pattern on the first object relative to the first and second bars, respectively, of the corresponding alignment pattern on the second object and proportional to the distance that the first and second bars of each alignment pattern on the first object are removed from the preselected position relative to the first and second bars, respectively, of the corresponding alignment pattern on the second object, and drive means responsive to those output signals for producing relative movement between the first and second objects to bring the first and second bars of each alignment pattern on the first object to the preselected position relative to the first and second bars, respectively, of the corresponding alignment pattern on the second object.
Claim 3
Dependent Claim
108 words
A system as in claim 1 wherein each alignment pattern on the second object comprises a first pair of elongated bars and a second pair of elongated bars at an angle to the first pair of bars substantially equal to the angle between the first and second bars of each alignment pattern on the first object, and wherein the first and second bars of each alignment pattern on the first object are positioned parallel to and at a preselected position spaced from the first and second pairs of bars, respectively, of the corresponding alignment pattern on the second object when the first and second objects are in alignment.
Claim 4
Dependent Claim
87 words
A system as in claim 2 wherein the first and second bars of the first alignment pattern on the first object are centrally spaced within the first and second pairs of bars, respectively, of the first alignment pattern on the second object in the preselected position, and wherein the first and second bars of the second alignment pattern on the first object are centrally spaced within the first and second pairs of bars, respectively, of the second alignment pattern on the second object in the preselected position.
Claim 5
Dependent Claim
390 words
A system as in claim 2 wherein said scanning means comprises means for projecting an image of the alignment patterns on the first and second objects at an image plane, an opaque movable member at said image plane having a first and a second pair of openings therein, one of the first pair of openings being oriented in the same direction as the first bar of the first alignment pattern on the first object and the first pair of bars of the first alignment pattern on the second object, the other of the first pair of openings oriented in the same direction as the second bar of the first alignment pattern on the first object and the second pair of bars of the first alignment pattern on the second object, one of the second pair of openings being oriented in the same direction as the first bar of the second alignment pattern on the first object and the first pair of bars of the second alignment pattern on the second object, and the other of the second pair of openings being oriented in the same direction as the second bar of the second alignment pattern on the first object and the second pair of bars of the second alignment pattern on the second object, means for moving said opaque member to scan the first bar and the first pair of bars of the first alignment patterns on the first and second objects with said one of the first pair of openings, to scan the second bar and the second pair of bars of the first alignment patterns on the first and second objects with said other of the first pair of openings, to scan the first bar and the first pair of bars of the second alignment patterns on the first and second objects with said one of the second pair of openings, and to scan the second bar and the second pair of bars of the second alignment patterns on the first and second objects with said other of the second pair of openings, and means for producing an electrical pulse as each of said openings passes over one of the corresponding bars aligned in the same direction as the opening, and wherein said measurement means is operable for determining the time intervals between the electrical pulses so produced.
Claim 6
Dependent Claim
74 words
A system as in claim 4 wherein said scanning means produces four sets of three electrical pulses each, one set of three electrical pulses for each bar of each alignment pattern on the first object and the corresponding pair of bars of the corresponding alignment pattern on the second object, respectively, and wherein said measurement means is operable for determining the time intervals between the electrical pulses in each set of three electrical pulses.
Claim 7
Dependent Claim
50 words
A system as in claim 5 wherein said measurement means comprises a clock pulse generator, three pulse counters, and means for directing clock pulses to separate ones of said pulse counters during the time intervals between three separate pairs of the electrical pulses in each set of three electrical pulses.
Claim 8
Dependent Claim
80 words
A system as in claim 6 wherein the direction each bar of each alignment pattern on the first object is off-center relative to the corresponding pair of bars of the corresponding alignment pattern on the second object is indicated by the particular one of said pulse counters that records the number of clock pulses representing the time interval between two of the electrical pulses produced by the corresponding pair of bars of the corresponding alignment pattern on the second object.
Claim 9
Dependent Claim
30 words
A system as in claim 4 wherein said opaque member comprises a belt, and wherein the first and second pairs of openings in said opaque member comprise elongated slots therein.
Claim 10
Dependent Claim
111 words
A system as in claim 4 wherein said measurement means comprises first circuit means responsive to the time intervals between the electrical pulses for producing an output indicative of the direction of each bar of each alignment pattern on the first object relative to the corresponding pair of bars of the corresponding alignment pattern on the second object, and second circuit means responsive to the time intervals between the electrical pulses for producing an output indicative of the distance each bar of each alignment pattern on the first object is removed from the preselected position relative to the corresponding pair of bars of the corresponding alignment pattern on the second object.
Claim 11
Dependent Claim
217 words
A system as in claim 2 wherein said measurement means comprises first circuit means responsive to said scanning means for producing position output signals indicative of the position of each of the first and second bars of each of the first and second alignment patterns on the first object relative to each of the corresponding first and second pairs of bars of each of the corresponding first and second alignment patterns on the second object, respectively, second circuit means responsive to said position output signals for producing output signals proportional to the distance each of the first and second bars of each of the first and second alignment patterns on the first object is removed from the preselected position relative to each of the corresponding first and second pairs of bars of each of the corresponding first and second alignment patterns on the second object, respectively, and third circuit means responsive to said position output signals for producing output signals proportional to the direction each of the first and second bars of each of the first and second alignment patterns on the first object is removed from the preselected position relative to each of the corresponding first and second pairs of bars of each of the corresponding first and second alignment patterns on the second object, respectively.
Claim 12
Dependent Claim
68 words
A system as in claim 10 wherein the output signals produced by said second circuit means comprise pulse trains, the number of pulses in each pulse train being proportional to the distance one of the bars of one of the alignment patterns on the first object is removed from the preselected position relative to the corresponding pair of bars of the corresponding alignment pattern on the second object.
Claim 13
Dependent Claim
55 words
A system as in claim 11 wherein said measurement means includes at least one up-down counter for counting the number of pulses in each pulse train produced by said second circuit means, each count being registered as an up count or a down count depending on the output signals produced by said third circuit means.
Claim 14
Dependent Claim
315 words
A system as in claim 1 wherein said scanning means comprises means for projecting an image of the alignment patterns on the first and second objects at an image plane, an opaque movable member at said image plane having a first and a second pair of openings therein, one of the first pair of openings being oriented in the same direction as the first bars of the first alignment patterns on the first and second objects, the other of the first pair of openings being oriented in the same direction as the second bars of the first alignment patterns on the first and second objects, one of the second pair of openings being oriented in the same direction as the first bars of the second alignment patterns on the first and second objects, and the other of the second pair of openings being oriented in the same direction as the second bars of the second alignment patterns on the first and second objects, means for moving said opaque member to scan the first bars of the first alignment patterns on the first and second objects with said one of the first pair of openings, to scan the second bars of the first alignment patterns on the first and second objects with said other of the first pair of openings, to scan the first bars of the second alignment patterns on the first and second objects with said one of the second pair of openings, and to scan the second bars of the second alignment patterns on the first and second objects with said other of the second pair of openings, and means for producing an electrical pulse as each of said openings passes over one of the corresponding bars aligned in the same direction as the opening, and wherein said measurement means is operable for determining the time intervals between the electrical pulses so produced.
Claim 15
Dependent Claim
30 words
A system as in claim 13 wherein said opaque member comprises a belt, and wherein the first and second pairs of openings in said opaque member comprise elongated slots therein.
Claim 16
Dependent Claim
107 words
A system as in claim 13 wherein said measurement means comprises first circuit means responsive to the time intervals between the electrical pulses for producing an output indicative of the direction of each bar of each alignment pattern on the first object relative to the corresponding bar of the corresponding alignment pattern on the second object, and second circuit means responsive to the time intervals between the electrical pulses for producing an output indicative of the distance each bar of each alignment pattern on the first object is removed from the preselected position relative to the corresponding bar of the corresponding alignment pattern on the second object.
Claim 17
Dependent Claim
210 words
A system as in claim 13 wherein said measurement means comprises first circuit means responsive to said scanning means for producing position output signals indicative of the position of each of the first and second bars of each of the first and second alignment patterns on the first object relative to each of the corresponding first and second bars of each of the corresponding first and second alignment patterns on the second object, respectively, second circuit means responsive to said position output signals for producing output signals proportional to the distance each of the first and second bars of each of the first and second alignment patterns on the first object is removed from the preselected position relative to each of the corresponding first and second bars of each of the corresponding first and second alignment patterns on the second object, respectively, and third circuit means responsive to said position output signals for producing output signals proportional to the direction each of the first and second bars of each of the first and second alignment patterns on the first object is removed from the preselected position relative to each of the corresponding first and second bars of each of the corresponding first and second alignment patterns on the second object.
Claim 18
Independent Claim
292 words
A system for aligning first and second relatively movable objects, where the first object has an alignment pattern thereon comprising first and second marks oriented at an angle relative to one another and the second object has a corresponding alignment pattern thereon comprising first and second marks oriented at substantially the same angle relative to one another as the first and second marks of the alignment pattern on the first object, said system comprising scanning means for scanning the alignment patterns on the first and second objects to produce output signals indicative of the positions of the first and second marks of the alignment pattern on the first object relative to the first and second marks, respectively, of the corresponding alignment pattern on the second object, control means coupled to the scanning means and responsive to the output signals therefrom for producing control signals proportional to the linear distance the first and second marks of the alignment pattern on the first object are removed from a preselected alignment position relative to the first and second marks, respectively, of the corresponding alignment pattern on the second object to control the relative movement between the first and second objects, and drive means coupled to the control means and responsive to the control signals therefrom for producing relative movement between the first and second objects to bring the first and second marks of the alignment pattern on the first object into the preselected alignment position relative to the first and second marks, respectively, of the corresponding alignment pattern on the second object with the first and second marks of the alignment pattern on the first object oriented substantially parallel to the first and second marks, respectively, of the corresponding alignment pattern on the second object.
Claim 19
Independent Claim
292 words
A system for aligning first and second relatively movable objects, where the first object has an alignment pattern thereon comprising first and second marks oriented at an angle relative to one another and the second object has a corresponding alignment pattern thereon comprising first and second marks oriented at substantially the same angle relative to one another as the first and second marks of the alignment pattern on the first object, said system comprising scanning means for scanning the alignment patterns on the first and second objects to produce output signals indicative of the positions of the first and second marks of the alignment pattern on the first object relative to the first and second marks, respectively, of the corresponding alignment pattern on the second object, control means coupled to the scanning means and responsive to the output signals therefrom for producing control signals proportional to the linear distance the first and second marks of the alignment pattern on the first object are removed from a preselected alignment position relative to the first and second marks, respectively, of the corresponding alignment pattern on the second object to control the relative movement between the first and second objects, and drive means coupled to the control means and responsive to the control signals therefrom for producing relative movement between the first and second objects to bring the first and second marks of the alignment pattern on the first object into the preselected alignment position relative to the first and second marks, respectively, of the corresponding alignment pattern on the second object with the first and second marks of the alignment pattern on the first object oriented substantially parallel to the first and second marks, respectively, of the corresponding alignment pattern on the second object.
Claim 20
Dependent Claim
82 words
A system as in claim 17 wherein the control means is responsive to the output signals from the scanning means for producing control signals indicative of the direction and proportional to the linear distance the first and second marks of the alignment pattern on the first object are removed from the preselected alignment position relative to the first and second marks, respectively, of the corresponding alignment pattern on the second object to control the relative movement between the first and second objects.
Claim 21
Dependent Claim
78 words
A system as in claim 18 wherein the first object has a pair of spaced alignment patterns thereon each comprising first and second marks oriented at an angle relative to one another, and the second object has a corresponding pair of spaced alignment patterns thereon each comprising first and second marks oriented at substantially the same angle relative to one another as the first and second marks of the pair of spaced alignment patterns on the first object.
Claim 22
Dependent Claim
132 words
A system as in claim 19 wherein each alignment pattern on the second object comprises a first pair of uniformly spaced first marks and a second pair of uniformly spaced second marks with those pairs of first and second marks oriented at substantially the same angle relative to one another as the first and second marks of the corresponding alignment pattern on the first object, and wherein the first and second marks of each alignment pattern on the first object are centrally spaced within the first and second pairs, respectively, of uniformly spaced first and second marks of the corresponding alignment pattern on the second object when the first and second marks of the alignment patterns on the first and second objects are in the preselected alignment position relative to one another.
Claim 23
Dependent Claim
82 words
A system as in claim 20 wherein the scanning means produces a set of three output pulses indicative of the positions of the first marks of each alignment pattern on the first object and the corresponding alignment pattern on the second object relative to one another, and another set of three output pulses indicative of the positions of the second marks of each alignment pattern on the first object and the corresponding alignment pattern on the second object relative to one another.
Claim 24
Dependent Claim
62 words
A system as in claim 21 wherein the control means includes a clock pulse generator, three pulse counters, and means for directing clock pulses from the clock pulse generator to different ones of the three pulse counters during three time intervals defined between three different pairs of the output pulses of each set of three output pulses produced by the scanning means.
Claim 25
Dependent Claim
28 words
A system as in claim 22 wherein the first and second marks of each alignment pattern on the first and second objects comprise nonparallel marks of uniform width.
Claim 26
Dependent Claim
31 words
A system as in claim 23 wherein the first and second marks of each alignment pattern on the first and second objects comprise substantially orthogonal bars or lines of uniform width.
Claim 27
Dependent Claim
27 words
A system as in claim 24 wherein the bars or lines are straight, of substantially the same shape, and of substantially uniform width along the length thereof.
Claim 28
Dependent Claim
111 words
A system as in claim 25 wherein the scanning means includes an opaque member provided with first and second openings corresponding to the first and second marks of the alignment patterns on the first and second objects for scanning those alignment patterns and further includes detection means responsive to changes in the amount of light passing through the first and second openings in the opaque member from the first and second objects, as the opaque member scans the alignment patterns on those objects, for producing the output signals, and wherein the control means is coupled to the detection means and responsive to the output signals therefrom for producing the control signals.
Claim 29
Dependent Claim
49 words
A system as in claim 26 wherein the first and second openings in the opaque member are shaped substantially in accordance with and oriented at substantially the same angle relative to one another as the first and second marks of the alignment patterns on the first and second objects.
Claim 30
Dependent Claim
14 words
A system as in claim 27 wherein the opaque member comprises a movable belt.
Claim 31
Dependent Claim
131 words
A system as in claim 17 wherein the alignment pattern on the second object comprises a first pair of uniformly spaced first marks and a second pair of uniformly spaced second marks with those pairs of first and second marks oriented at substantially the same angle relative to one another as the first and second marks of the alignment pattern on the first object, and wherein the first and second marks of the alignment pattern on the first object are centrally spaced within the first and second pairs, respectively, of uniformly spaced first and second marks of the corresponding alignment pattern on the second object when the first and second marks of the alignment patterns on the first and second objects are in the preselected alignment position relative to one another.
Claim 32
Dependent Claim
82 words
A system as in claim 29 wherein the scanning means produces a set of three output pulses indicative of the positions of the first marks of the alignment pattern on the first object and the corresponding alignment pattern on the second object relative to one another, and another set of three output pulses indicative of the positions of the second marks of the alignment pattern on the first object and the corresponding alignment pattern on the second object relative to one another.
Claim 33
Dependent Claim
85 words
A system as in claim 30 wherein the control means is responsive to the sets of three output pulses from the scanning means for producing control signals indicative of the direction and proportional to the linear distance the first and second marks of the alignment pattern on the first object are removed from the preselected alignment position relative to the first and second marks, respectively, of the corresponding alignment pattern on the second object to control the relative movement between the first and second objects.
Claim 34
Dependent Claim
62 words
A system as in claim 31 wherein the control means includes a clock pulse generator, three pulse counters, and means for directing clock pulses from the clock pulse generator to different ones of the three pulse counters during three time intervals defined between three different pairs of the output pulses of each set of three output pulses produced by the scanning means.
Claim 35
Dependent Claim
28 words
A system as in claim 17 wherein the first and second marks of each alignment pattern on the first and second objects comprise nonparallel marks of uniform width.
Claim 36
Dependent Claim
31 words
A system as in claim 33 wherein the first and second marks of each alignment pattern on the first and second objects comprise substantially orthogonal bars or lines of uniform width.
Claim 37
Dependent Claim
27 words
A system as in claim 34 wherein the bars or lines are straight, of substantially the same shape, and of substantially uniform width along the length thereof.
Claim 38
Dependent Claim
82 words
A system as in claim 35 wherein the control means is responsive to the output signals from the scanning means for producing control signals indicative of the direction and proportional to the linear distance the first and second marks of the alignment pattern on the first object are removed from the preselected alignment position relative to the first and second marks, respectively, of the corresponding alignment pattern on the second object to control the relative movement between the first and second objects.
Claim 39
Dependent Claim
111 words
A system as in claim 17 wherein the scanning means includes an opaque member provided with first and second openings corresponding to the first and second marks of the alignment patterns on the first and second objects for scanning those alignment patterns and further includes detection means responsive to changes in the amount of light passing through the first and second openings in the opaque member from the first and second objects, as the opaque member scans the alignment patterns on those objects, for producing the output signals, and wherein the control means is coupled to the detection means and responsive to the output signals therefrom for producing the control signals.
Claim 40
Dependent Claim
49 words
A system as in claim 37 wherein the first and second openings in the opaque member are shaped substantially in accordance with and oriented at substantially the same angle relative to one another as the first and second marks of the alignment patterns on the first and second objects.
Claim 41
Dependent Claim
14 words
A system as in claim 38 wherein the opaque member comprises a movable belt.
Claim 42
Dependent Claim
82 words
A system as in claim 39 wherein the control means is responsive to the output signals from the detection means for producing control signals indicative of the direction and proportional to the linear distance the first and second marks of the alignment pattern on the first object are removed from the preselected alignment position relative to the first and second marks, respectively, of the corresponding alignment pattern on the second object to control the relative movement between the first and second objects.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-04 | 1979-11-03 | 1980-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-04 | 1983-11-03 | 1984-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-04 | 1987-11-03 | 1988-05-04 | $7700.00 | Window Closed / Lapsed |