US4741212A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for determining structural defects in semiconductor wafers by ultrasonic microscopy
Assignee: Intersil Corp
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Filing: 1986-07-31
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Granted: 1988-05-03
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Expires: 2006-07-31
Abstract
Abstract A method and apparatus for determining the location and size of structural defects in a body of solid material, particularly regions of thermoplastic deformation in semiconductor wafers. An acoustical focused beam generated by an ultrasonic transducer, having a pulsed frequency of at least 75 MHZ, is transmitted through the body to provide an attenuated signal pattern which manifests structural defects, such as slip planes which can result in wafer warp, as well as cracks, bubbles, foreign particles or segregation zones and internal interfaces.
Inventors
- 👤 Walther Rehwald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:59
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/22; G01N29/221; G01H; G01H3/00; G01H3/10; G01H3/12; G01H3/125; G01N29/04; G01N29/06; G01N29/225; G01N2291/00; G01N2291/01; G01N2291/015; G01N2291/02; G01N2291/023; G01N2291/0237; G01N2291/028; G01N2291/0289; G01N2291/10; G01N2291/102; G01N2291/26; G01N2291/269; G01N2291/2697
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
168 words
A method for locating and quantifying a structure defect in the form of a slip plane caused by thermoplastic deformation, in a semiconductor body comprising the steps of: (a) focusing an incident beam of acoustic energy within the body, said incident beam having a wavelength that is significantly smaller than the thickness of said body and a beam waist diameter that is smaller than the thickness of said body; (b) providing relative movement between said body and said beam so that a portion of the major surface is scanned in a given direction; (c) providing a position signal indicative of the position of said surface portion receiving said incident beam; (d) detecting the acoustic energy of the beam transmitted through said body and producing a transmitted electrical signal corresponding to the attenuation of said acoustic beam through said body; and (e) processing said transmitted electrical signal such that attenuation peaks in said transmitted signal are indicative of the location and magnitude of said structural defect in said body.
Claim 2
Independent Claim
168 words
A method for locating and quantifying a structure defect in the form of a slip plane caused by thermoplastic deformation, in a semiconductor body comprising the steps of: (a) focusing an incident beam of acoustic energy within the body, said incident beam having a wavelength that is significantly smaller than the thickness of said body and a beam waist diameter that is smaller than the thickness of said body; (b) providing relative movement between said body and said beam so that a portion of the major surface is scanned in a given direction; (c) providing a position signal indicative of the position of said surface portion receiving said incident beam; (d) detecting the acoustic energy of the beam transmitted through said body and producing a transmitted electrical signal corresponding to the attenuation of said acoustic beam through said body; and (e) processing said transmitted electrical signal such that attenuation peaks in said transmitted signal are indicative of the location and magnitude of said structural defect in said body.
Claim 3
Dependent Claim
30 words
The method of claim 1 further comprising the step of: (a) scanning in both X and Y directions over said surface portion to provide signal data for storage or mapping.
Claim 4
Dependent Claim
14 words
The method of claim 1 wherein said body is immersed in a liquid bath.
Claim 5
Dependent Claim
19 words
The method of claim 1 wherein said beam vibrates acoustically at a frequency that is at least 75 MHz.
Claim 6
Dependent Claim
27 words
The method of claim 1 wherein the acoustic attenuation signal is used to detect areas of excessive dislocation density and to predict warpage of a semiconductor wafer.
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) | 1991-05-03 | 1991-11-02 | 1992-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-03 | 1995-11-02 | 1996-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-03 | 1999-11-02 | 2000-05-03 | $7700.00 | Window Closed / Lapsed |