US4470063A
Expired / Lapsed
US
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Copper matrix electrode having carbon fibers therein
Assignee: Hitachi Ltd
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Filing: 1981-11-18
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Granted: 1984-09-04
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Expires: 2001-11-18
Abstract
Abstract A semiconductor device includes a semiconductor substrate having electrodes brazed thereto. The electrode is made of a Cu-C composite material in which carbon fibers are embedded in copper matrix. The carbon fibers are so disposed as to be in a ring-like shape or a loop shape substantially in parallel with a surface of the semiconductor substrate onto which the electrode is brazed. The carbon fibers disposed in an outer peripheral portion have a higher longitudinal elastic modulus than that of the carbon fibers positioned at a central portion of the electrode. The electrode thus has a thermal expansion coefficient approximating to that of the semiconductor substrate. Content of copper can be increased at the central portion of the electrode for attaining a high thermal conductivity.
Inventors
- 👤 Hideo Arakawa
- 👤 Keiichi Kuniya
- 👤 Takashi Namekawa
- 👤 Masabumi Ohashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:02
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/117; H10W; H10W70/00; H10W70/20; H10W70/24; H10W70/28; H10W72/00; H10W72/30; H10W74/00; H10W74/10; H10W74/111; H10W74/131; H10W74/137; H10W76/00; H10W76/10; H10W76/12; H10W76/13; H10W76/136; H10W76/138; H10W72/071; H10W72/073; H10W72/07331; H10W72/07337; H10W72/351; H10W72/353; H10W72/354; H10W72/50; H10W72/531; H10W72/5363; H10W72/851; H10W72/874; H10W72/884
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
112 words
A semiconductor device comprising: (a) a semiconductor substrate having at least one pn-junction; (b) at least one electrode for supporting said semiconductor substrate, said electrode being made of a composite material in which carbon fibers are embedded in a ring-like shape in a copper matrix, the plane of the ring-like shape being substantially parallel with the surface of said electrode for supporting said semiconductor substrate; wherein at least the carbon fibers embedded in an outer peripheral portion of said electrode having a greater longitudinal elastic modulus than that of the carbon fibers embedded in a central portion of said electrode; and (c) brazing material for attaching said electrodes to said semiconductor substrate.
Claim 2
Dependent Claim
112 words
A semiconductor device comprising: (a) a semiconductor substrate having at least one pn-junction; (b) at least one electrode for supporting said semiconductor substrate, said electrode being made of a composite material in which carbon fibers are embedded in a ring-like shape in a copper matrix, the plane of the ring-like shape being substantially parallel with the surface of said electrode for supporting said semiconductor substrate; wherein at least the carbon fibers embedded in an outer peripheral portion of said electrode having a greater longitudinal elastic modulus than that of the carbon fibers embedded in a central portion of said electrode; and (c) brazing material for attaching said electrodes to said semiconductor substrate.
Claim 3
Dependent Claim
37 words
A semiconductor device according to claim 1, wherein said carbon fibers are embedded in the copper matrix in an array selected from a group consisting of an annular array, a spiral array and combinations of these arrays.
Claim 4
Dependent Claim
28 words
A semiconductor device according to claim 1, wherein density of distribution of the carbon fiber is decreased toward a center of said electrode from the outer-peripheral portion thereof.
Claim 5
Dependent Claim
31 words
A semiconductor device according to claim 1, wherein the copper matrix contains a minute amount of at least one element selected from the group consisting of titanium, zirconium, boron and hafnium.
Claim 6
Dependent Claim
31 words
A semiconductor device according to claim 1, wherein the longitudinal elastic modulus of said carbon fibers is decreased progressively toward a center of said electrode from the outer peripheral portion thereof.
Claim 7
Dependent Claim
84 words
A semiconductor device according to claim 1, wherein said ring-like shape of said carbon fibers comprises an arrangement wherein carbon fibers having a high longitudinal elastic modulus are formed in a net-like structure of intersecting lines to define at least one closed ring-like shape in said outer peripheral portion of said electrode, and wherein carbon fibers having a low longitudinal elastic modulus are embedded in said electrode within the boundaries of said closed ring-like shape formed by said high longitudinal elastic modulus carbon fibers.
Claim 8
Dependent Claim
31 words
A semiconductor device according to claim 3, wherein said density of distribution of the carbon fibers is progressively decreased toward the center of said electrode from the outer peripheral portion thereof.
Claim 9
Dependent Claim
78 words
A semiconductor device comprising: (a) a semiconductor substrate having at least one pn-junction; (b) at least one electrode for supporting said semiconductor substrate, said electrode being made of a composite material in which first and second types of carbon fibers are embedded in a copper matrix, wherein said first type of carbon fibers has a greater longitudinal elastic modulus than said second type of carbon fibers; and (c) brazing material for attaching said electrodes to said semiconductor substrate.
Claim 10
Dependent Claim
78 words
A semiconductor device comprising: (a) a semiconductor substrate having at least one pn-junction; (b) at least one electrode for supporting said semiconductor substrate, said electrode being made of a composite material in which first and second types of carbon fibers are embedded in a copper matrix, wherein said first type of carbon fibers has a greater longitudinal elastic modulus than said second type of carbon fibers; and (c) brazing material for attaching said electrodes to said semiconductor substrate.
Claim 11
Dependent Claim
46 words
A semiconductor device according to claim 8, wherein said first type of carbon fiber is located in an outer peripheral portion of said electrode and said second type of carbon fibers is located in an inner portion of said electrodes enclosed by said outer peripheral portion.
Claim 12
Dependent Claim
24 words
A semiconductor device according to claim 9, wherein said first and second types of carbon fibers are intermingled with one another in said electrode.
Claim 13
Dependent Claim
29 words
A semiconductor device according to claim 10, wherein density of distribution of the carbon fiber is decreased toward a center of said electrode from the outer peripheral portion thereof.
Claim 14
Dependent Claim
29 words
A semiconductor device according to claim 11, wherein density of distribution of the carbon fiber is decreased toward a center of said electrode from the outer peripheral portion thereof.
Claim 15
Dependent Claim
189 words
A semiconductor device comprising: (a) a semiconductor substrate having at least one pn-junction; (b) at least one electrode for supporting said semiconductor substrate, said electrode being made of a composite material in which first and second types of carbon fibers are embedded in a copper matrix, said first type of carbon fibers having a greater longitudinal elastic modulus than said second type of carbon fibers, wherein said first type of carbon fibers is located in an outer peripheral portion of said electrode and said second type of carbon fibers is located in an inner portion of said electrode enclosed by said outer peripheral portion so that said outer peripheral portion of said electrode has a lower thermal expansion coefficient than said inner portion to restrict expansion of said inner portion, and further wherein a density of distribution of the carbon fibers is decreased toward a center of said electrode from the outer peripheral portion thereof so that said inner portion has a lower density of carbon fibers and a higher heat conductivity than said outer peripheral portion; and (c) brazing material for attaching said electrodes to said semiconductor substrate.
Claim 16
Dependent Claim
189 words
A semiconductor device comprising: (a) a semiconductor substrate having at least one pn-junction; (b) at least one electrode for supporting said semiconductor substrate, said electrode being made of a composite material in which first and second types of carbon fibers are embedded in a copper matrix, said first type of carbon fibers having a greater longitudinal elastic modulus than said second type of carbon fibers, wherein said first type of carbon fibers is located in an outer peripheral portion of said electrode and said second type of carbon fibers is located in an inner portion of said electrode enclosed by said outer peripheral portion so that said outer peripheral portion of said electrode has a lower thermal expansion coefficient than said inner portion to restrict expansion of said inner portion, and further wherein a density of distribution of the carbon fibers is decreased toward a center of said electrode from the outer peripheral portion thereof so that said inner portion has a lower density of carbon fibers and a higher heat conductivity than said outer peripheral portion; and (c) brazing material for attaching said electrodes to said semiconductor substrate.
Claim 17
Dependent Claim
49 words
A semiconductor device according to claim 1, wherein carbon fibers embedded in said outer peripheral portion have a longitudinal elastic modulus of 36,000 to 45,000 kg f/mm 2 and carbon fibers embedded in said central portion have a longitudinal elastic modulus of 20,000 to 31,000 kg f/mm 2 .
Claim 18
Dependent Claim
46 words
A semiconductor device according to claim 8, wherein said first type of carbon fibers has a longitudinal elastic modulus of 36,000 to 45,000 kg f/mm 2 and said second type of carbon fibers has a longitudinal elastic modulus of 20,000 to 31,000 kg f/mm 2 .
Claim 19
Dependent Claim
46 words
A semiconductor device according to claim 13, wherein said first type of carbon fibers has a longitudinal elastic modulus of 36,000 to 45,000 kg f/mm 2 and said second type of carbon fibers has a longitudinal elastic modulus of 20,000 to 31,000 kg f/mm 2 .
References Cited (Backward Citations)
US4196442A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-04 | 1988-03-05 | 1988-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-04 | 1992-03-05 | 1992-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-04 | 1996-03-05 | 1996-09-04 | $7700.00 | Window Closed / Lapsed |