US3901423A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for fracturing crystalline materials
Assignee: Purdue Research Foundation
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Filing: 1973-11-26
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Granted: 1975-08-26
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Expires: 1993-11-26
Abstract
Abstract This disclosure relates to a method for fracturing crystalline materials whereby thin wafers may be produced with minimum waste of the crystal.
Inventors
- 👤 Benny M Hillberry
- 👤 Robert J Myers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:41
CPC Classifications
B; B28; B28D; B28D5/00; B28D5/0005; B28D5/0017; B28D5/0023; B28D5/0011; Y; Y10; Y10T; Y10T225/00; Y10T225/10; Y10T225/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
117 words
A method for producing thin wafers from crystalline material characterized by: the step of introducing a preselected stress concentration into a crystal along a line to establish a predetermined fracture plane that will produce a thin wafer whereby the location of the fracture initiation is predetermined; the step of applying a continuing tensile stress acting normally upon the predetermined fracture plane; and the step of initiating fracturing of the crystal while maintaining the application of tensile stress by application of a sudden acting fracturing force acting substantially perpendicular to the predetermined fracture plane whereby said applied fracturing force and tensile stress enables saId thin wafers to be produced at said location predetermined by said introduced stress concentration.
Claim 2
Independent Claim
117 words
A method for producing thin wafers from crystalline material characterized by: the step of introducing a preselected stress concentration into a crystal along a line to establish a predetermined fracture plane that will produce a thin wafer whereby the location of the fracture initiation is predetermined; the step of applying a continuing tensile stress acting normally upon the predetermined fracture plane; and the step of initiating fracturing of the crystal while maintaining the application of tensile stress by application of a sudden acting fracturing force acting substantially perpendicular to the predetermined fracture plane whereby said applied fracturing force and tensile stress enables saId thin wafers to be produced at said location predetermined by said introduced stress concentration.
Claim 3
Dependent Claim
29 words
The method according to claim 1 in which the stress concentration is accomplished by a mechanical expedient causing physical deformation of the crystal to produce a predetermined force concentration.
Claim 4
Dependent Claim
32 words
The method according to claim 1 in which the step of introducing the tensile stress internally in the material is accomplished by application of a loading mode to the crystal exterior surface.
Claim 5
Dependent Claim
25 words
The method according to claim 3 in which said loading mode is applied by application of at least one external force acting upon said crystal.
Claim 6
Dependent Claim
27 words
The method according to claim 1 in which the step of fracturing the crystal is accomplished by a force applied to the material by a mechanical expedient.
Claim 7
Dependent Claim
30 words
The method according to claim 5 in which said force applied by said mechanical expedient is by means of a wedge applied in the direction of the predetermined fracture plane.
Claim 8
Independent Claim
103 words
A method for producing thin wafers from a crystalline rod characterized by the steps of: providing a flat side on the rod, which flat is disposed normally to a line extending from the mid-point of said flat to the center of said rod; notching said flat surface along a line where it is desired to initiate fracture of the rod; applying tensile stress to the rod stock in an axial direction; and applying a fracturing force into said notch acting substantially perpendicular to the longitudinal rod axis whereby the rod is fractured substantially transversely with respect to the longitudinal axis of the rod.
Claim 9
Independent Claim
103 words
A method for producing thin wafers from a crystalline rod characterized by the steps of: providing a flat side on the rod, which flat is disposed normally to a line extending from the mid-point of said flat to the center of said rod; notching said flat surface along a line where it is desired to initiate fracture of the rod; applying tensile stress to the rod stock in an axial direction; and applying a fracturing force into said notch acting substantially perpendicular to the longitudinal rod axis whereby the rod is fractured substantially transversely with respect to the longitudinal axis of the rod.
Claim 10
Dependent Claim
34 words
The method of claim 7 in which the fracture is initiated by driving a wedge into the notch and a support force is applied to prevent movement of the rod in a transverse direction.
References Cited (Backward Citations)
US1797748A
Cited
US2630174A
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US3187739A
Cited
US3542266A
Cited
US3659764A
Cited
US3800991A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-25 | 1979-02-24 | 1979-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-25 | 1983-02-24 | 1983-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-25 | 1987-02-24 | 1987-08-26 | $7700.00 | Window Closed / Lapsed |