US4636073A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Universal calibration standard for surface inspection systems
Assignee: International Business Machines Corp
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Filing: 1984-10-31
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Granted: 1987-01-13
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Expires: 2004-10-31
Abstract
Abstract A universal calibration standard for surface inspection systems has a plurality of hemispherical pads which simulate the liquid scattering due to particulate contamination. The hemispherical pads scatter light irrespective of angles of illumination and detection and of rotational orientation, and are fabricated using ball-limiting metallurgical techniques. Any number and sizes of pads can be arranged on a substrate and the standard can be repeatedly cleaned, thereby having a long useful life.
Inventors
- 👤 Randal R. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:50
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/93; G01N21/94; G01N21/17; G01N21/47; G01N21/4785
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
86 words
A test standard for calibrating an optical wafer surface inspection system, said test standard comprising a plurality of pads bonded to a flat, optically reflective substrate, said plurality of pads being hemispherically shaped and comprised of a layer of solder and at least one other metallic layer selected from the group consisting of titanium, copper, gold, chromium, and nickel, whereby the hemispherical pads simulate particulate contamination on the substrate and the wafer surface inspection system can be calibrated independently of the angles of illumination and detection.
Claim 2
Dependent Claim
86 words
A test standard for calibrating an optical wafer surface inspection system, said test standard comprising a plurality of pads bonded to a flat, optically reflective substrate, said plurality of pads being hemispherically shaped and comprised of a layer of solder and at least one other metallic layer selected from the group consisting of titanium, copper, gold, chromium, and nickel, whereby the hemispherical pads simulate particulate contamination on the substrate and the wafer surface inspection system can be calibrated independently of the angles of illumination and detection.
Claim 3
Dependent Claim
36 words
The test standard as claimed in claim 1 wherein at least one of said pads has a diameter different from the rest of said pads, whereby multiple size sensitivities of said inspection system can be determined.
Claim 4
Dependent Claim
25 words
The optical calibration test standard according to claim 1, wherein said hemispherical pads are arranged in at least one patterned array on said test standard.
Claim 5
Dependent Claim
17 words
The optical calibration test standard according to claim 1 wherein said flat, optically reflective surface is metallic.
Claim 6
Dependent Claim
18 words
The optical calibration test standard according to claim 1 wherein said flat, optically reflective surface is electrically conductive.
Claim 7
Dependent Claim
19 words
The optical calibration test standard according to claim 1 wherein said flat, optically reflective surface is a semiconductor wafer.
Claim 8
Dependent Claim
25 words
The optical calibration test standard according to claim 1 wherein said solder is selected from the group consisting of gold, tin, lead, indium and bismuth.
Claim 9
Dependent Claim
22 words
The calibration test standard as recited in claim 1 wherein said hemispherical pads have diameters in the range oe to 150 microns.
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) | 1990-01-12 | 1990-07-14 | 1991-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-12 | 1994-07-14 | 1995-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-12 | 1998-07-14 | 1999-01-13 | $7700.00 | Window Closed / Lapsed |