US3663326A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Article holding methods and assemblage
Assignee: AT&T Inc
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Filing: 1970-01-09
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Granted: 1972-05-16
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Expires: 1990-01-09
Abstract
Abstract Methods involve holding an array of semiconductor devices on a substrate by means of a polyester mesh screen and photoresist material. After the array of devices have been formed by photoresist and etch techniques from a slice waxed to the substrate, the photoresist material is removed from the array but not from the substrate surrounding the array. The polyester mesh screen is placed over and forced against the array and photoresist material while the wax is removed with a solvent. The solvent softens the photoresist material so that the forced screen embeds in the photoresist. Upon removal from the influence of the solvent, the photoresist material rehardens fastening the screen to the substrate with the devices retained between the screen and the substrate in their original orientation and array. The assemblage of substrate, photoresist material and screen permits the devices, no longer waxed to the substrate, to be transported to other operations where the screen is peeled off and the devices removed.
Inventors
- 👤 William R Wanesky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:18
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/70; H10P72/74; H10P95/00; H10W; H10W74/00; H10W74/40; H10W74/47; H10P72/7428
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
163 words
A method of holding a plurality of cemented articles on a support after the removal of the cement, which comprises the steps of: applying, on at least two opposed edge portions of the support, a first material softenable by a cement solvent; forming the articles cemented to the support between said opposed edge portions of the first material; forcing a layer of a compressible second material over the articles and the first material to compress said second material against said articles and said first material; dissolving the cement with the solvent to loosen the articles on the support and to soften said first material, the compressed second material expanding to compensate for a void left by the dissolved cement and to retain the articles against the support, the force embedding said second material in the softened first material; and hardening the first material to secure the second material in the first material and thereby holding the articles between said support and second material.
Claim 2
Independent Claim
181 words
A method of holding an array of cemented articles on a support after removal of the cement by a solvent, which comprises the steps of: forming an array of articles cemented to a support and surrounded by a normally hard first material that is softenable by the solvent; placing a layer of compressible and porous second material over the articles and the first material; exerting a force against the second material to force and compress said second material against the articles and the first material; dissolving the cement with the solvent to remove the cement, soften said first material and permit said forced second material to embed in the softened first material durIng the cement removal, the compressed second material expanding to compensate for the cement removal; removing the support, the articles and said first and second materials from the influence of said solvent to thereby reharden said first material; and releasing the force after the cement is removed and said first material rehardened so that the articles remain held to the support in the array by the second porous material.
Claim 3
Dependent Claim
16 words
The method, as recited in claim 3, wherein said first material is a photosensitive, etch-resistant material.
Claim 4
Dependent Claim
132 words
The method, as recited in claim 3, wherein forming the array of articles, comprises the steps of: coating a slice and support with photosensitive etch-resistant material that is softenable with a solvent, the slice being cemented with wax to the support and containing the array of articles to be held after the wax is removed; exposing the photosensitive material to form a line image of an array of rectangles, the periphery of each rectangle surrounding an article of the array; developing the array image to remove the etch-resistant material and expose the slice along the lines of the array; etching through the slice along the lines to separate the slice into an array of individual articles; and removing the etch-resistant material from the articles thereby leaving the etch-resistant material surrounding said array.
Claim 5
Dependent Claim
19 words
The method as recited in claim 5 wherein the second material is a polyester mesh screen having interwoven convolutions.
Claim 6
Dependent Claim
22 words
The method, as recited in claim 3, wherein the step of dissolving the cement comprises immersing the array in a cement solvent.
Claim 7
Dependent Claim
90 words
The method, as recited in claim 3, wherein dissolving the cement comprises the steps of: condensing trichlorethylene vapor on an inverted conical condenser which is positioned with the apex of the cone above and adjacent the center of the array of articles; and dripping the condensed vapor on the center of the array so that the condensate flows radially from the center of the array outward washing the cement from beneath the articles and softening the first material, the force embedding said forced second material in the softened first material.
Claim 8
Independent Claim
249 words
A method of holding an array of oriented semiconductor devices on a substrate, the devices being in a slice of semiconductor material cemented with wax to the substrate, which comprises the steps of: coating the slice and substrate with photosensitive etch-resistant material that is softenable with a solvent; exposing the photosensitive material to form a line image of an array of rectangles, the periphery of each rectangle surrounding a device of the array; developing the line image to remove the etch-resistant material along the lines of the array; etching through the slice along the lines to separate the slice into an array of individual devices; removing the etch-resistant material from the devices while leaving the etch-resistant material surrounding the array of devices; placing a compressible polyester-mesh first screen over the devices and etch-resistant material; forcing the first screen against the devices and etch-resistant material with a stainless steel second screen to compress the first screen; dissolving the cement with solvent to free the devices and soften the etch-resistant material, the compressed first screen embedding in the softened etch-resistant material and expanding to compensate for the cement removal; removing the substrate, devices and the screens from the influence of said solvent to reharden the etch-resistant material around the first screen, thereby fastening the first screen to the substrate periphery; and releasing the force after the cement is removed and the etch-resistant material rehardened so that the devices remain held to the substrate by the first screen in the oriented array.
Claim 9
Dependent Claim
31 words
The method, as recited in claim 9, wherein the step of dissolving the cement comprises: immersing an assemblage of the substrate, devices and screens in a solvent to remove the wax.
Claim 10
Dependent Claim
12 words
The method as recited in claim 9 wherein the solvent is trichlorethylene.
Claim 11
Dependent Claim
292 words
Method for holding an array of oriented, beam-lead semiconductor devices on a substrate after wax removal, the devices being in a slice of semiconductor material and cemented with wax to the substrate, which comprises the steps of: coating the slice and substrate with photosensitive, etch-resistant material that is softenable with a solvent; exposing the photosensitive etch resistant material to a line image of an array of rectangles, the periphery of each rectangle encompassing one device of the array; developing the image to remove the etch-resistant material along the lines of the rectangles; etching through the slice along the lines of the rectangles to separate the slice into an array of individual devices; removing the etch-resistant material from the devices thereby leaving the etch-resistant material surrounding said array of devices; placing a first compressible polyester-mesh screen over the devices and etch-resistant material; forcing the first screen against the devices and the etch-resistant material with a second stainless steel screen to compress the first screen; condensing trichlorethylene vapor on an inverted conical condenser, the apex of the cone being positioned above and adjacent the center of the array of devices; dripping the condensed vapor on the center of the array so that the condensate flows radially from the center of the array outward washing the wax from beneath the devices and softening the etch-resistant material, the compressed first screen embedding in the softened etch-resistant material and expanding to compensate for the wax removal; removing the substrate, devices and screens from the condensate so that the etch-resistant material rehardens around the first mesh screen thereby fastening the first screen to the substrate; and removing the second mesh screen so that the devices are retained in the oriented array on the substrate by the first screen.
References Cited (Backward Citations)
US3152939A
Cited
US3537925A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |