US3811069A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal stabilization of an alignment detection device
Assignee: Westinghouse Electric Corp
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Filing: 1972-06-20
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Granted: 1974-05-14
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Expires: 1992-06-20
Abstract
Abstract A radiation beam such as an electron beam of predetermined preferably polygonal cross-section is rapidly precision aligned with a radiation detector mark of like cross-section on a member such as a resist coated substrate by measuring the radiation induced output signal from the mark. The output signal is proportional to the portion or area of the mark irradiated by the beam. The impingement of the patterned radiation beam on the member is moved in a predetermined overlapping, preferably circular or elliptic pattern over the detector mark to modulate the output signal from the mark. At least two frequency signals are extracted from the output signal and compared with a preselected alignment relationship. The over-lapping pattern is changed in position, and the comparing and changing in position repeated until the extracted frequency signals compare in the preselected relationship. Preferably the rate at which the change in position proceeds is controlled by a ratio of the two frequency signals as the preselected alignment relationship is approached.
Inventors
- 👤 Keeffe T O
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:59
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/30; H01J37/304; H01J37/3045
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
125 words
A method for aligning a radiation beam of predetermined cross-section with a detector mark of like cross-section comprising the steps of: a. moving the radiation beam in a predetermined overlapping pattern over at least a portion of the detector mark to produce a modulating signal from the detector mark proportional to said portion overlapped; b. extracting from the modulating signal at least two frequency signals to electrically compare the frequency signals; c. comparing relative amplitudes of the extracted frequdncy signals with each other to determine whether the amplitudes compare in a preselected alignment relationship; and d. changing position of the overlapping pattern over the detector mark and repeating steps (c) and (d) until the amplitudes of the extracted frequency signals compare in said preselected relationship.
Claim 2
Independent Claim
125 words
A method for aligning a radiation beam of predetermined cross-section with a detector mark of like cross-section comprising the steps of: a. moving the radiation beam in a predetermined overlapping pattern over at least a portion of the detector mark to produce a modulating signal from the detector mark proportional to said portion overlapped; b. extracting from the modulating signal at least two frequency signals to electrically compare the frequency signals; c. comparing relative amplitudes of the extracted frequdncy signals with each other to determine whether the amplitudes compare in a preselected alignment relationship; and d. changing position of the overlapping pattern over the detector mark and repeating steps (c) and (d) until the amplitudes of the extracted frequency signals compare in said preselected relationship.
Claim 3
Dependent Claim
41 words
A method of aligning a radiation beam of predetermined cross-section with a detector mark of like cross-section as set forth in claim 1 wherein: the predetermined overlapping pattern is a curvilinear path selected from the group consisting of circular and elliptic.
Claim 4
Independent Claim
122 words
A method for aligning a radiation beam of predetermined polygonal cross-section with a detector mark of like polygonal cross-section comprising the sTeps of: a. moving the radiation beam in a predetermined overlapping pattern over at least a portion of the detector mark proportional to said portion overlapped; b. extracting from the modulating signal the fundamental signal and the harmonic signal corresponding in number to sides of the polygonal cross-section; c. comparing relative amplitudes of the extracted fundamental and harmonic signals with each other to determine whether the amplitudes compare in a preselected alignment relationship; d. changing position of the overlapping pattern over the detector mark and repeating steps (c) and (d) until the amplitudes of the extracted signals compare in preselected relationship.
Claim 5
Independent Claim
122 words
A method for aligning a radiation beam of predetermined polygonal cross-section with a detector mark of like polygonal cross-section comprising the sTeps of: a. moving the radiation beam in a predetermined overlapping pattern over at least a portion of the detector mark proportional to said portion overlapped; b. extracting from the modulating signal the fundamental signal and the harmonic signal corresponding in number to sides of the polygonal cross-section; c. comparing relative amplitudes of the extracted fundamental and harmonic signals with each other to determine whether the amplitudes compare in a preselected alignment relationship; d. changing position of the overlapping pattern over the detector mark and repeating steps (c) and (d) until the amplitudes of the extracted signals compare in preselected relationship.
Claim 6
Dependent Claim
49 words
A method of aligning a radiation beam of predetermined polygonal cross-section with a detector mark of like polygonal cross-section as set forth in claim 3 wherein: the predetermined cross-sections of the radiation beam and the detector mark are substantially square and the extracted harmonic signal is the fourth harmonic.
Claim 7
Dependent Claim
43 words
A method of aligning a radiation beam of predetermined polygonal cross-section with a detector mark of the polygonal cross-section as set forth in claim 3 wherein: the predetermined overlapping pattern is a curvilinear path selected from the group consisting of circular and elliptic.
Claim 8
Dependent Claim
60 words
A method for aligning a radiation beam of predetermined cross-section with a detector mark of like cross-section as set forth in claim 1 comprising additionally: e. changing position of the overlapping pattern over the detector mark at a controlled rate proportional to a ratio of the frequency signals extracted from the output signal as the preselected alignment relationship is approached.
Claim 9
Dependent Claim
187 words
Apparatus for automatically aligning an electron beam of predetermined cross-section with a detector mark of like cross-section comprising: a. cathodic means capable of producing an electron beam of pre-determined cross-section; b. a member spaced from the cathodic means having thereon a detector mark of predetermined cross-section of substantially similar dimensions to the electron beam capable of having at least portions thereof overlapped by the beam and producing an electric output signal proportional to said portions overlapped; c. modulating means for moving the electron beam in a predetermined overlapping pattern over the detector mark to produce a modulated output signal from the detector mark; d. electrical means for extracting at least two frequency signals from the modulated output signal to electrically compare the frequency signals; e. electrical means for comparing relative amplitudes of the frequency signals with each other to determine whether the amplitudes compare in a preselected alignment relationship; f. positioning means for automatically changing position of the overlapping pattern of the electron beam on the detector mark; and g. electrical means for stopping the positioning means when the frequency signals compare in the preselected alignment relationship.
Claim 10
Dependent Claim
187 words
Apparatus for automatically aligning an electron beam of predetermined cross-section with a detector mark of like cross-section comprising: a. cathodic means capable of producing an electron beam of pre-determined cross-section; b. a member spaced from the cathodic means having thereon a detector mark of predetermined cross-section of substantially similar dimensions to the electron beam capable of having at least portions thereof overlapped by the beam and producing an electric output signal proportional to said portions overlapped; c. modulating means for moving the electron beam in a predetermined overlapping pattern over the detector mark to produce a modulated output signal from the detector mark; d. electrical means for extracting at least two frequency signals from the modulated output signal to electrically compare the frequency signals; e. electrical means for comparing relative amplitudes of the frequency signals with each other to determine whether the amplitudes compare in a preselected alignment relationship; f. positioning means for automatically changing position of the overlapping pattern of the electron beam on the detector mark; and g. electrical means for stopping the positioning means when the frequency signals compare in the preselected alignment relationship.
Claim 11
Dependent Claim
41 words
Apparatus for automatically aligning an electron beam of predetermined cross-section with a detector mark of like cross-section as set forth in claim 7 wherein: the predetermined overlapping pattern is a curvilinear path selected from the group consisting of circular and elliptic.
Claim 12
Dependent Claim
214 words
Apparatus for automatically aligning an electron beam of predetermined cross-section with a detector mark of like cross-section comprising: a. cathodic means capable of producing an electron beam of predetermined polygonal shape cross-section; b. a member spaced from the cathodic means having thereon a detector mark of predetermined polygonal shape cross-section of substantially similar dimensions to the electron beam capable of having at least portions thereof overlapped by the beam and producing an electric output signal proportional to said portions overlapped; c. modulating means for moving the electron beam in a predeterminEd overlapping pattern over the detector mark to produce a modulated output signal from the detector mark; d. electrical means for extracting at least two frequency signals including the fundamental signal and the harmonic signal corresponding in number to sides of the polygonal cross-sections from the modulated output signal to electrically compare the fundamental and harmonic signals; e. electrical means for comparing relative amplitudes of the fundamental and harmonic signals with each other to determine whether the amplitudes compare in a preselected alignment relationship; f. positioning means for automatically changing position of the overlapping pattern of the electron beam on the detector mark; and g. electrical means for stopping the positioning means when the fundamental and harmonic signals compare in the preselected alignment relationship.
Claim 13
Dependent Claim
214 words
Apparatus for automatically aligning an electron beam of predetermined cross-section with a detector mark of like cross-section comprising: a. cathodic means capable of producing an electron beam of predetermined polygonal shape cross-section; b. a member spaced from the cathodic means having thereon a detector mark of predetermined polygonal shape cross-section of substantially similar dimensions to the electron beam capable of having at least portions thereof overlapped by the beam and producing an electric output signal proportional to said portions overlapped; c. modulating means for moving the electron beam in a predeterminEd overlapping pattern over the detector mark to produce a modulated output signal from the detector mark; d. electrical means for extracting at least two frequency signals including the fundamental signal and the harmonic signal corresponding in number to sides of the polygonal cross-sections from the modulated output signal to electrically compare the fundamental and harmonic signals; e. electrical means for comparing relative amplitudes of the fundamental and harmonic signals with each other to determine whether the amplitudes compare in a preselected alignment relationship; f. positioning means for automatically changing position of the overlapping pattern of the electron beam on the detector mark; and g. electrical means for stopping the positioning means when the fundamental and harmonic signals compare in the preselected alignment relationship.
Claim 14
Dependent Claim
46 words
Apparatus for automatically aligning an electron beam of predetermined cross-section with a detector mark of like cross-section as set forth in claim 9 wherein: the predetermined cross-sections of the electron beam and the detector mark are substantially square and the harmonic signal is the fourth harmonic.
Claim 15
Dependent Claim
41 words
Apparatus for automatically aligning an electron beam of predetermined cross-section with a detector mark of like cross-section as set forth in claim 9 wherein: the predetermined overlapping pattern is a curvilinear path selected from the group consisting of circular and elliptic.
Claim 16
Dependent Claim
54 words
Apparatus for automatically aligning an electron beam of predetermined cross-section with a detector mark of like cross-section as set forth in claim 7 comprising: h. electrical means for automatically changing position by the positioning means at a controlled rate proportional to a ratio of two frequency signals as the preselected alignment relationship is approached.
Claim 17
Dependent Claim
151 words
Apparatus for automatically aligning an electron beam with a detector mark comprising: a. cathodic means capable of producing an electron beam of predetermined cross-section; b. a member spaced from the cathodic means having thereon a detector mark of predetermined cross-section of substantially similar dimensions to the electron beam capable of having at least portions thereof overlapped by the beam and producing an electric output signal proportional to said portions overlapped; c. positioning means for automatically changing position of the overlapping pattern of the electron beam on the detector mark as a function of the output signals from the detector mark; and d. electrical means for automatically changing position by the positioning means at a controlled rate proportional to a ratio of two frequency signals extracted from the output signal as the ratio approaches a preselected value corresponding to alignment of the electron beam and the detector mark within an established tolerance.
Claim 18
Dependent Claim
151 words
Apparatus for automatically aligning an electron beam with a detector mark comprising: a. cathodic means capable of producing an electron beam of predetermined cross-section; b. a member spaced from the cathodic means having thereon a detector mark of predetermined cross-section of substantially similar dimensions to the electron beam capable of having at least portions thereof overlapped by the beam and producing an electric output signal proportional to said portions overlapped; c. positioning means for automatically changing position of the overlapping pattern of the electron beam on the detector mark as a function of the output signals from the detector mark; and d. electrical means for automatically changing position by the positioning means at a controlled rate proportional to a ratio of two frequency signals extracted from the output signal as the ratio approaches a preselected value corresponding to alignment of the electron beam and the detector mark within an established tolerance.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-13 | 1977-11-12 | 1978-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-13 | 1981-11-12 | 1982-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-13 | 1985-11-12 | 1986-05-14 | $7700.00 | Window Closed / Lapsed |