Patent US3915769A successfully refreshed from Google Patents.
US3915769A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protected crossover circuits and method of protecting the circuits
Assignee: AT&T Inc
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Filing: 1973-07-02
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Granted: 1975-10-28
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Expires: 1993-07-02
Abstract
Abstract In crossover circuits, air-insulated crossover conductors on a substrate for hybrid integrated networks are solidly supported to prevent electrical shorts between the crossover and any underlying conductors. In doing this, a resin is applied over the surface of the substrate. Capillary attraction forms an agglomeration of the resin about each crossover conductor. The resin is then hardened to form supports for the crossover conductors. Subsequent etching and rinsing removes all of the resin from the surface of the substrate but leaves it under the crossover conductors to continue supporting them. With the resin so removed, semiconductor chips may be bonded to terminal areas on the substrate.
Inventors
- 👤 Robert L Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:37
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/60; H10W70/62; H10W70/65; H05; H05K; H05K3/00; H05K3/46; H05K3/4685; Y; Y10; Y10T; Y10T428/00; Y10T428/23907; Y10T428/23986
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
122 words
A METHOD OF FORMING AN INSULATIVE SUPPORT BETWEEN A CIRCUIT SUBSTRATE AND A CONDUCTIVE MEMBER SPACED FROM THE SUBSTRATE, WHICH COMPRISES: APPLYING A HARDENABLE, WETTING LIQUID SUBSTANCE, WHICH IS AN ELECTRIC INSULATOR WHEN HARDENED OR AT LEAST PARTIALLY CURED, TO THE SUBSTRATE TO FORM A LAYER OF SUFFICIENT THICKNESS TO PERMIT CAPILLARY ATTRACTION TO DRAW THE SUBSTANCE INTO, AND FILL THE SPACE BETWEEN, THE MEMBER AND THE SUBSTRATE, HARDENING THE LAYER TO FORM THE INSULATIVE SUPPORT BETWEEN THE SUBSTRATE AND THE MEMBER, AND REMOVING A TOP PORTION OF THE SURFACE OF THE HARDENED LAYER SUBSTANTIALLY UNIFORMLY UNTIL THE LAYER IS ELIMINATED EVERYWHERE FROM THE SUBSTRATE EXCEPT FOR THOSE PORTIONS OF THE LAYER THAT FORM THE SUPPORT BETWEEN THE MEMBER AND THE SUBSTRATE.
Claim 2
Independent Claim
122 words
A METHOD OF FORMING AN INSULATIVE SUPPORT BETWEEN A CIRCUIT SUBSTRATE AND A CONDUCTIVE MEMBER SPACED FROM THE SUBSTRATE, WHICH COMPRISES: APPLYING A HARDENABLE, WETTING LIQUID SUBSTANCE, WHICH IS AN ELECTRIC INSULATOR WHEN HARDENED OR AT LEAST PARTIALLY CURED, TO THE SUBSTRATE TO FORM A LAYER OF SUFFICIENT THICKNESS TO PERMIT CAPILLARY ATTRACTION TO DRAW THE SUBSTANCE INTO, AND FILL THE SPACE BETWEEN, THE MEMBER AND THE SUBSTRATE, HARDENING THE LAYER TO FORM THE INSULATIVE SUPPORT BETWEEN THE SUBSTRATE AND THE MEMBER, AND REMOVING A TOP PORTION OF THE SURFACE OF THE HARDENED LAYER SUBSTANTIALLY UNIFORMLY UNTIL THE LAYER IS ELIMINATED EVERYWHERE FROM THE SUBSTRATE EXCEPT FOR THOSE PORTIONS OF THE LAYER THAT FORM THE SUPPORT BETWEEN THE MEMBER AND THE SUBSTRATE.
Claim 3
Dependent Claim
75 words
A method according to claim 1, wherein: the substance applied to the substrate is a methyl phenyl polysiloxane resin; hardening the layer formed from the substance comprises partially curing the resin; and removing a portion of the surface of the layer comprises etching the resin layer in an etchant consisting substantially of tetramethylammonium hydroxide dissolved in methanol, 1-methyl 2-pyrrolidinone, and isopropyl alcohol, rinsing the substrate in water after the etching, and then drying the substrate.
Claim 4
Dependent Claim
15 words
A method according to claim 2, comprising: further curing the resin after drying the substrate.
Claim 5
Dependent Claim
58 words
A method according to claim 3, wherein the resin is applied to a substrate having electrical conductors on its surface, wherein the member is a crossover conductor vertically spaced from an underlying conductor by about 0.001 to about 0.005 inch and wherein the resin is applied to form a layer which has a thickness of about 0.001 inch.
Claim 6
Independent Claim
134 words
A method of applying a supporting and insulating substance about and under conductive members mounted to and at least partially spaced from the surface of a circuit substrate, which comprises: applying the substance substantially uniformly over at least a portion of the surface of the substrate that includes the conductive members; flowing the substance as a wetting liquid to agglomerate the applied substance by capillary attraction about and under the conductive members to form a layer having an increased thickness in the areas of the conductive members; hardening the applied substance; and then removing a top portion of substantially uniform thickness of the layer of the applied substance to eliminate it from the surface of the workpiece other than under the conductive members and in The areas of increased thickness adjacent the conductive members.
Claim 7
Independent Claim
134 words
A method of applying a supporting and insulating substance about and under conductive members mounted to and at least partially spaced from the surface of a circuit substrate, which comprises: applying the substance substantially uniformly over at least a portion of the surface of the substrate that includes the conductive members; flowing the substance as a wetting liquid to agglomerate the applied substance by capillary attraction about and under the conductive members to form a layer having an increased thickness in the areas of the conductive members; hardening the applied substance; and then removing a top portion of substantially uniform thickness of the layer of the applied substance to eliminate it from the surface of the workpiece other than under the conductive members and in The areas of increased thickness adjacent the conductive members.
References Cited (Backward Citations)
US3525617A
Cited
US3461524A
Cited
US3758943A
Cited
US3672985A
Cited
US3693251A
Cited
US3762040A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |