US5023407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Printed circuit board with a uniform conductive layer formed by equalization of metals therein
Assignee: Hitachi Ltd
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Filing: 1989-08-07
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Granted: 1991-06-11
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Expires: 2009-08-07
Abstract
Abstract A metal layer other than gold is formed on a ceramic substrate, a gold layer is further formed on said metal layer, and then a high density beam is applied to the treated substrate member. Thereby, the metal of the underlayer diffused through the grain boundaries of gold up to the surface of the gold layer by heat treatment or the like is uniformly mixed with gold to form an alloyed layer excellent in wettability to a solder. At the same time, nonmetallic impurities such as carbon adhering onto the surface of the gold layer are melted and removed.
Inventors
- 👤 Mitugu Shirai
- 👤 Kaoru Katayama
- 👤 Hideaki Sasaki
- 👤 Shinichi Kazui
- 👤 Ryohei Satoh
- 👤 Tateoki Miyauchi
- 👤 Mamoru Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:41
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/22; H05K3/24; H05K3/245; H05K3/246; H05K1/00; H05K1/02; H05K1/09; H10; H10W; H10W70/00; H10W70/01; H10W70/05; H05K1/03; H05K1/0306; H05K1/092; H05K2203/00; H05K2203/07; H05K2203/0703; H05K2203/0723; H05K2203/10; H05K2203/107; H05K3/244; H05K3/30; H05K3/32; H05K3/34; H05K3/3465; H10W72/00; H10W72/071; H10W72/075; H10W72/07531; H10W72/07532; H10W72/07533; H10W72/50; H10W72/531; H10W72/536; H10W72/551; H10W72/552; H10W72/5522
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
77 words
A circuit board, comprising: a substrate; and a junction pad or zone provided on the substrate and having a uniformly alloyed layer of gold and a metal other than gold at least on a surface or the junction pad or zone, said uniformly alloyed layer formed by melting and resoldifiying a non-uniform layer of gold and a metal other than gold, the junction pad or zone being an area suited for bonding with an external wire element.
Claim 2
Dependent Claim
77 words
A circuit board, comprising: a substrate; and a junction pad or zone provided on the substrate and having a uniformly alloyed layer of gold and a metal other than gold at least on a surface or the junction pad or zone, said uniformly alloyed layer formed by melting and resoldifiying a non-uniform layer of gold and a metal other than gold, the junction pad or zone being an area suited for bonding with an external wire element.
Claim 3
Dependent Claim
18 words
A circuit board as claimed in claim 1, wherein said junction part is a soldering pad or zone.
Claim 4
Dependent Claim
19 words
A circuit board as claimed in claim 1, wherein said junction part is a wire bonding pad or zone.
Claim 5
Dependent Claim
15 words
A circuit board as claimed in claim 1, wherein said substrate is a ceramic substrate.
Claim 6
Dependent Claim
29 words
A circuit board as claimed in claim 1, wherein said metal other than gold is a metal containing nickel excellent in connecting property to gold as a main component.
Claim 7
Dependent Claim
83 words
A circuit board, comprising: a substrate; and a junction part provided on the substrate, said junction part including a layer of plated gold and a uniformly alloyed layer of comprising gold and a metal other than gold at least on a surface of the layer of plated gold, said uniformly alloyed layer formed by instantaneously melting and resoldifiying a non-uniform layer of gold and a metal other than gold, the junction part being an area suited for bonding with an external wire element.
Claim 8
Dependent Claim
83 words
A circuit board, comprising: a substrate; and a junction part provided on the substrate, said junction part including a layer of plated gold and a uniformly alloyed layer of comprising gold and a metal other than gold at least on a surface of the layer of plated gold, said uniformly alloyed layer formed by instantaneously melting and resoldifiying a non-uniform layer of gold and a metal other than gold, the junction part being an area suited for bonding with an external wire element.
Claim 9
Dependent Claim
16 words
A circuit board as claimed in claim 6, wherein said junction part is a soldering part.
Claim 10
Dependent Claim
17 words
A circuit board as claimed in claim 6, wherein said junction part is a wire bonding part.
Claim 11
Dependent Claim
15 words
A circuit board as claimed in claim 7, wherein said substrate is a ceramic substrate.
Claim 12
Dependent Claim
32 words
A circuit board as claimed in claim 7, wherein said metal other than gold is a metal containing nickel or the like excellent in connecting property to gold as a main component.
Claim 13
Dependent Claim
94 words
A circuit board, comprising: a substrate; a circuit pattern part provided on the substrate; and a junction part formed at a predetermined portion of said circuit pattern part, wherein said junction part is an area suited for bonding with an external wire element and comprises a gold layer and a connecting layer for connecting said gold layer to said circuit pattern part, said gold layer having a uniformly alloyed layer of gold and a metal precipitated from said connecting layer formed by melting and resolidifing by laser beam irradiation at least on the surface.
Claim 14
Dependent Claim
94 words
A circuit board, comprising: a substrate; a circuit pattern part provided on the substrate; and a junction part formed at a predetermined portion of said circuit pattern part, wherein said junction part is an area suited for bonding with an external wire element and comprises a gold layer and a connecting layer for connecting said gold layer to said circuit pattern part, said gold layer having a uniformly alloyed layer of gold and a metal precipitated from said connecting layer formed by melting and resolidifing by laser beam irradiation at least on the surface.
Claim 15
Dependent Claim
16 words
A circuit board as claimed in claim 11, wherein said junction part is a soldering part.
Claim 16
Dependent Claim
17 words
A circuit board as claimed in claim 11, wherein said junction part is a wire bonding part.
Claim 17
Dependent Claim
15 words
A circuit board as claimed in claim 11, wherein said substrate is a ceramic substrate.
Claim 18
Dependent Claim
30 words
A circuit board as claimed in claim 11, wherein a metal for said connecting layer contains nickel or the like excellent in connecting property to gold as a main component.
Claim 19
Dependent Claim
28 words
A circuit board as claimed in claim 11, wherein a metal for said circuit part contains at least one selected from tungsten and copper as a main component.
References Cited (Backward Citations)
US4268585A
Cited
US4434544A
Cited
US4786523A
Cited
US4521476A
Cited
US4681656A
Cited
US4620264A
Cited
US4597029A
Cited
US4737839A
Cited
US4785137A
Cited
JPS62256961A
Cited
JPS6397382A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-10 | 1994-12-10 | 1995-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-10 | 1998-12-10 | 1999-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-10 | 2002-12-10 | 2003-06-11 | $7700.00 | Window Closed / Lapsed |