Patent US4071944A successfully refreshed from Google Patents.
US4071944A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adhesively and magnetically holding an article
Assignee: AT&T Inc
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Filing: 1975-10-20
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Granted: 1978-02-07
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Expires: 1995-10-20
Abstract
Abstract In fabrication of articles, such as semiconductor devices, the articles are adhered to the surface of a magnetized carrier having grooves with a suitable adhesive. Preferably, the grooves are parallel and in sets which intersect each other. The articles are made susceptible to the attraction of a magnetic field. The adhesive is removed by the flow of solvent vapor and liquid through the grooves while the articles are retained in their original position by magnetic forces. In an alternate method, the articles may be adhered initially to a nonmagnetic substrate, made susceptible to the attraction of magnetic field and transferred to a grooved, magnetized carrier. Any adhesive which clings to the articles is removed by solvent vapor and liquid as before.
Inventors
- 👤 John T. Chuss
- 👤 Henry H. Krechel
- 👤 Joseph R. Purvis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:15
CPC Classifications
H; H10; H10P; H10P54/00; H10P72/00; H10P72/04; H10P72/0442; H10P72/70; H10P72/74; H10W; H10W72/00; H10W72/01; H10W72/0198; H10W72/071; H10W72/073; H10W72/07331; H10W72/07337; H10W72/30; H10W72/351; H10W72/353; H10W72/354; Y; Y10; Y10T; Y10T156/00; Y10T156/11; Y10T156/1153; Y10T156/1158
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
145 words
A method of holding a wafer of semiconductor material having an array of semiconductor devices formed therein, which comprises the steps of: adhering the wafer to a magnetized carrier with an adhesive, the carrier having intersecting sets of parallel grooves and material selected from the group consisting of barrium ferrite, strontium ferrite, alnico, or a mixture of barrium and strontium ferrite; separating the wafer into individual devices; screening magnetic ink on the individual devices; partially curing the ink; electrically testing the devices; completing the curing of the ink; and placing the carrier in trichlorethylene solvent vapor and condensing the vapor to form the liquid solvent thereon, the solvent flowing over the surface and through the grooves in the carrier to rapidly and completely remove the adhesive from beneath the devices while the magnetic forces maintain the location and orientation of the devices on the carrier.
Claim 2
Independent Claim
145 words
A method of holding a wafer of semiconductor material having an array of semiconductor devices formed therein, which comprises the steps of: adhering the wafer to a magnetized carrier with an adhesive, the carrier having intersecting sets of parallel grooves and material selected from the group consisting of barrium ferrite, strontium ferrite, alnico, or a mixture of barrium and strontium ferrite; separating the wafer into individual devices; screening magnetic ink on the individual devices; partially curing the ink; electrically testing the devices; completing the curing of the ink; and placing the carrier in trichlorethylene solvent vapor and condensing the vapor to form the liquid solvent thereon, the solvent flowing over the surface and through the grooves in the carrier to rapidly and completely remove the adhesive from beneath the devices while the magnetic forces maintain the location and orientation of the devices on the carrier.
Claim 3
Dependent Claim
38 words
The method of claim 1 wherein the partial curing of the ink is done by heating it at a temperature which is sufficiently low to avoid melting the adhesive while still being able to partially cure the ink.
Claim 4
Independent Claim
182 words
A method of handling a wafer of semiconductor material having an array of semiconductor devices formed therein, wherein the wafer has been adhered to a nonmagnetic support with an adhesive, which comprises the steps of: separating the wafer into individual devices; screening magnetic ink on the individual devices to make them magnetic; partially curing the ink; electrically testing the devices to determine the good ones; completing the curing of the ink; dissolving a portion of the adhesive; melting the remaining adhesive to free the devices from the magnetic support; transferring the devices to a magnetized carrier, the carrier having intersecting sets of parallel grooves and material selected from the group consisting of barrium ferrite, strontium ferrite, alnico, or a mixture of barrium and strontium ferrite; and placing the carrier in trichloroethylene solvent vapor and condensing the vapor to form the liquid solvent thereon, the solvent flowing over the surface and through the grooves in the carrier to rapidly and completely remove any adhesive transferred with the devices while the magnetic forces maintain the location and orientation of the devices on the carrier.
Claim 5
Independent Claim
182 words
A method of handling a wafer of semiconductor material having an array of semiconductor devices formed therein, wherein the wafer has been adhered to a nonmagnetic support with an adhesive, which comprises the steps of: separating the wafer into individual devices; screening magnetic ink on the individual devices to make them magnetic; partially curing the ink; electrically testing the devices to determine the good ones; completing the curing of the ink; dissolving a portion of the adhesive; melting the remaining adhesive to free the devices from the magnetic support; transferring the devices to a magnetized carrier, the carrier having intersecting sets of parallel grooves and material selected from the group consisting of barrium ferrite, strontium ferrite, alnico, or a mixture of barrium and strontium ferrite; and placing the carrier in trichloroethylene solvent vapor and condensing the vapor to form the liquid solvent thereon, the solvent flowing over the surface and through the grooves in the carrier to rapidly and completely remove any adhesive transferred with the devices while the magnetic forces maintain the location and orientation of the devices on the carrier.
Claim 6
Dependent Claim
38 words
The method of claim 3, wherein the partial curing of the ink is done by heating it at a temperature which is sufficiently low to avoid melting the adhesive while still being able to partially cure the ink.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-06 | 1981-08-08 | 1982-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-06 | 1985-08-08 | 1986-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-06 | 1989-08-08 | 1990-02-07 | $7700.00 | Window Closed / Lapsed |