EP0628806A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Image measurement system and method
Assignee: International Business Machines Corp
•
Filing: 1994-04-28
•
Granted: —
•
Expires: 2014-04-28
Abstract
Abstract An apparatus and method for determining the characteristics of a photolithographic mask (44) including a multi-wavelength light source (20), frequency selection means (22) for providing light of a selected frequency from the light source, coherence adjusting means (24-39) for adjusting coherence of the selected light, positioning means (42) for adjustable positioning of an object (44) with respect to the apparatus (12), and an imaging means (46, 48) for producing an enlarged optically equivalent image of the mask (44), the imaging means (46, 48) including an adjustment means (50) for adjusting numerical aperture, and image capture means (15) for capturing the image produced by the imaging means (46, 48). The light may be in the ultraviolet range and the image capture means (15) may be ultraviolet CCD camera. <IMAGE>
Inventors
- 👤 Russell Alan Budd
- 👤 Isabella Diana Min Chang
- 👤 Derek Brian Dove
- 👤 John Leroy Staples
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 12:10
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/68; G03F1/82; G03F1/84; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G03F7/00; G03F7/70; G03F7/70483; G03F7/70605; G03F7/70616; G03F7/7065; G03F7/70653; G03F7/70666; G01N21/8851; G01N2021/8887; G01N2021/95676
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
90 words
An image measurement system (12) comprising: a light source (20); means (22) for providing light of a selected frequency; coherence adjusting means (24-39) for adjusting coherence of the light; positioning means (42) for adjustably positioning an object (44) with respect to said system (12); imaging means (46, 48) for producing an enlarged optically equivalent stepper image of said object (44); said imaging means (46, 48) including an adjustment means (50) for adjusting numerical aperture; and image capture means (15) for capturing an image produced by said imaging means (46, 48).
Claim 2
Dependent Claim
35 words
The system (12) of claim 1 wherein said coherence adjusting means (24-39) includes angle adjusting means (34) for adjusting an angle of said light with respect to an optical axis (45) of said system (12).
Claim 3
Dependent Claim
38 words
The system (12) of claim 1 or 2 wherein said light source (20) comprises a multiwavelength light generator and frequency selection means for selecting a frequency of light produced by said generator for use by said system (12).
Claim 4
Independent Claim
27 words
The system (12) according to any one of the above claims further comprising display means (16) for displaying the image captured by said image capture means (15).
Claim 5
Independent Claim
27 words
The system (12) according to any one of the above claims further comprising analyzing means (14) for analyzing the image captured by said image capture means (15).
Claim 6
Dependent Claim
17 words
The system (12) of claim 5 wherein said analyzing means (14) comprises a programmed digital computer (14).
Claim 7
Independent Claim
27 words
The system (12) according to any one of the above claims further comprising control means (39) for controlling size of an illuminated region of the object (44).
Claim 8
Independent Claim
34 words
The system (12) according to any one of the above claims further comprising focus adjustment means (52), said image capture means (15) capturing data at selected focal positions of said focus adjustment means (52).
Claim 9
Independent Claim
46 words
The system (12) according to any one of the above claims wherein said focus adjustment means (52) comprises: an optical plate (66) for changing optical path length, and means (70) for introducing and withdrawing said optical plate (66) from an optical axis (45) of said system.
Claim 10
Independent Claim
41 words
The system (12) according to any one of the above claims wherein said image capture means (15) comprises a plurality of electronic imaging devices (15A, 15B, 15C), each said device being disposed in a different image plane of said system (12).
Claim 11
Dependent Claim
51 words
The system (12) of claim 10 wherein a first (15B) of said devices (15A, 15B, 15C) is displaced from a focal plane is a first direction and a second (15C) of said devices (15A, 15B, 15C) is displace from said focal plane in a second direction opposite to said first direction.
Claim 12
Dependent Claim
25 words
The system (12) of claim 11 further comprising combining means (62) for combining signals produced by said first device (15B) and said second device (15C).
Claim 13
Dependent Claim
28 words
The system (12) of claim 12 wherein said combining means (62) performs real time subtraction of the signal from said first device (15B) and said second device (15C).
Claim 14
Independent Claim
56 words
A method for producing images of an object (44) comprising the steps of providing electromagnetic energy of a selected frequency; adjusting coherence of the energy provided; positioning the object so that said electromagnetic energy illuminates a selected portion of the object; producing an enlarged optically stepper equivalent image of the object; and capturing the image produced.
Claim 15
Dependent Claim
27 words
The method of claim 14 further comprising the steps of extracting data from the image, and analyzing the data to determine the optical characteristics of the object.
Claim 16
Dependent Claim
16 words
The method of claim 14 further comprising capturing successive images at points above and below focus.
Claim 17
Dependent Claim
30 words
The method of claim 14 wherein the step of producing an optically stepper equivalent image includes adjusting a numerical aperture of an imaging system (12) used to produce said image.
Claim 18
Independent Claim
22 words
The system (12) or method according to any one of the above claims wherein the object (44) is a chrome photolithographic mask.
Claim 19
Independent Claim
22 words
The system (12) or method according to any one of the above claims wherein the object (44) is a phase shift mask.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.