Patent US4814945A successfully refreshed from Google Patents.
US4814945A
Expired / Lapsed
US
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Multilayer printed circuit board for ceramic chip carriers
Assignee: Northrop Grumman Corp
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Filing: 1987-09-18
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Granted: 1989-03-21
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Expires: 2007-09-18
Abstract
Abstract A multilayer printed circuit board in which multiple layers of a composite material, fabricated by the lay-up of an aramid fiber tape, are employed to provide a circuit board with a desired coefficient of thermal expansion. Tape lay-up of aramid fibers provides a composite layer having a lower thermal coefficient of expansion than a composite layer fabricated from woven aramid fibers. Degradation in the tensile modulus of elasticity caused by the over and under characteristics of woven fabrics is also eliminated by tape lay-up, thus providing a circuit board with better mechanical strength. In addition, tape lay-up reduces the amount of resin required to fabricate the circuit board and eliminates the need for twisting the aramid fibers into yarns and then weaving the yarns, thus reducing the cost of the circuit board.
Inventors
- 👤 Joseph D. Leibowitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:15
CPC Classifications
H; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/0313; H05K1/0353; H05K1/0366; H05K3/00; H05K3/46; H05K3/4611; H05K3/4626; H05K2201/00; H05K2201/01; H05K2201/0137; H05K2201/0154; H05K2201/0183; H05K2201/0195; H05K2201/02; H05K2201/0275; H05K2201/0278; H05K2201/0287; H05K2201/06; H05K2201/068; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/29; Y10T428/2904; Y10T428/2905
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
118 words
A multilayer printed circuit board, comprising: a plurality of layers of a composite material fabricated by lay-up of an armid fiber tape, each composite layer including two outer layers and two inner layers of the aramid fiber tape, the aramid fiber tape being oriented in the X direction in the outer layers and in the Y direction in the inner layers; and a plurality of layers of copper used to establish connections between electrical components to be mounted on the circuit board; wherein the layers are bonded together to form a multilayer printed circuit board having a coefficient of thermal expansion that is approximately equal to that of the electrical components to be mounted on the circuit board.
Claim 2
Dependent Claim
118 words
A multilayer printed circuit board, comprising: a plurality of layers of a composite material fabricated by lay-up of an armid fiber tape, each composite layer including two outer layers and two inner layers of the aramid fiber tape, the aramid fiber tape being oriented in the X direction in the outer layers and in the Y direction in the inner layers; and a plurality of layers of copper used to establish connections between electrical components to be mounted on the circuit board; wherein the layers are bonded together to form a multilayer printed circuit board having a coefficient of thermal expansion that is approximately equal to that of the electrical components to be mounted on the circuit board.
Claim 3
Dependent Claim
33 words
A multilayer printed circuit board as set forth in claim 1, wherein the aramid fiber tape is a single layer of aramid fibers coated with a resin and heated to a semi-cured stage.
Claim 4
Dependent Claim
21 words
A multilayer printed circuit board as set forth in claim 1, wherein the layers are bonded together with insulating adhesive layers.
Claim 5
Dependent Claim
25 words
A multilayer printed circuit board as set forth in claim 3, wherein the insulating adhesive layes are each a single layer of aramid fiber tape.
Claim 6
Dependent Claim
29 words
A multilayer printed circuit board as set forth in claim 3, wherein the insulating adhesive layers are each a single layer of woven aramid fibers impregnated with a resin.
Claim 7
Dependent Claim
18 words
A multilayer printed circuit board as set forth in claim 2, wherein the resin is an epoxy resin.
Claim 8
Dependent Claim
18 words
A multilayer printed circuit board as set forth in claim 2, wherein the resin is a polyimide resin.
Claim 9
Dependent Claim
116 words
A multilayer printed circuit board, comprising: a plurality of layers of a composite material fabricated by lay-up of a fiber tape, each composite layer including two outer layers and two inner layers of the fiber tape, the fiber tape being oriented in the X direction in the outer layers and in the Y direction in the inner layers; and a plurality of layers of conductive material used to establish connections between electrical components to be mounted on the circuit board; wherein the layers are bonded together to form a multilayer printed circuit board having a coefficient of thermal expansion that is approximately equal to that of the electrical components to be mounted on the circuit board.
Claim 10
Dependent Claim
116 words
A multilayer printed circuit board, comprising: a plurality of layers of a composite material fabricated by lay-up of a fiber tape, each composite layer including two outer layers and two inner layers of the fiber tape, the fiber tape being oriented in the X direction in the outer layers and in the Y direction in the inner layers; and a plurality of layers of conductive material used to establish connections between electrical components to be mounted on the circuit board; wherein the layers are bonded together to form a multilayer printed circuit board having a coefficient of thermal expansion that is approximately equal to that of the electrical components to be mounted on the circuit board.
Claim 11
Dependent Claim
31 words
A multilayer printed circuit board as set forth in claim 8, wherein the fiber tape is a single layer of fibers coated with a resin and heated to a semi-cured stage.
Claim 12
Dependent Claim
21 words
A multilayer printed circuit board as set forth in claim 8, wherein the layers are bonded together with insulating adhesive layers.
Claim 13
Dependent Claim
24 words
A multilayer printed circuit board as set forth in claim 10, wherein the insulating adhesive layers are each a single layer of fiber tape.
Claim 14
Dependent Claim
28 words
A multilayer printed circuit board as set forth in claim 10, wherein the insulating adhesive layers are each a single layer of woven fibers impregnated with a resin.
Claim 15
Dependent Claim
18 words
A multilayer printed circuit board as set forth in claim 9, wherein the fiber is an aramid fiber.
Claim 16
Dependent Claim
18 words
A multilayer printed circuit board as set forth in claim 9, wherein the resin is an epoxy resin.
Claim 17
Dependent Claim
18 words
A multilayer printed circuit board as set forth in claim 9, wherein the resin is a polyimide resin.
Claim 18
Dependent Claim
17 words
A multilayer printed circuit board as set forth in claim 8, wherein the conductive metal is copper.
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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) | 1992-03-20 | 1992-09-19 | 1993-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-20 | 1996-09-19 | 1997-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-20 | 2000-09-19 | 2001-03-21 | $7700.00 | Window Closed / Lapsed |