EP0380289A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A process of manufacturing a multi-layer ceramic substrate assembly
Assignee: Fujitsu Ltd
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Filing: 1990-01-23
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Granted: —
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Expires: 2010-01-23
Abstract
Abstract A multi-layer ceramic substrate assembly comprising a multi-layer ceramic substrate (1) including a via-conductor (2) and an interconnecting line (3) and having a surface, a first soldering pad (31) on the surface of the substrate and connected to the via-conductor (2), a second soldering pad (33) on the surface of the substrate adjacent to the first soldering pad, a connecting pattern (34, 35) on the surface of the substrate for connecting the first and second soldering pads, the connecting pattern being made of an electric conductor wettable with a solder, and a solder dam (16) formed on the connecting pattern between the first and second soldering pads, the solder dam being made of a metal or a metal alloy or compound not wettable with a solder. The electric conductivity of the connecting pattern (34, 35) is carried by a metal having a good electric conductivity and the solder dam (16) is made of a metal or a metal alloy or compound not wettable with a solder, whereby the solder dam stops a flow of a solder through the dam or under the dam. A simple and reliable process for forming such a solder dam is also provided.
Inventors
- 👤 Kazuaki Satou
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 14:27
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/3452; H10; H10W; H10W70/00; H10W70/099; H10W90/00; H10W90/701; H05K1/00; H05K1/02; H05K1/03; H05K1/0306; H05K2201/00; H05K2201/03; H05K2201/0302; H05K2201/0317; H05K2201/20; H05K2201/2081; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917; Y10T428/24926
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
117 words
A multi-layer ceramic substrate assembly comprising a multi-layer ceramic substrate (1); a first soldering pad (31) on a surface of the substrate and connected to a via-conductor (2); a second soldering pad (33) on the surface of the substrate adjacent to the first soldering pad (31); a connecting pattern (34, 35) on the surface of the substrate for connecting the first and second soldering pads, the connecting pattern being made of an electric conductor wettable with a solder; and a solder dam (16) on the connecting pattern between the first and second soldering pads, characterised in that the solder dam (16) is made of a metal or a metal alloy or compound not wettable with a solder.
Claim 2
Dependent Claim
117 words
A multi-layer ceramic substrate assembly comprising a multi-layer ceramic substrate (1); a first soldering pad (31) on a surface of the substrate and connected to a via-conductor (2); a second soldering pad (33) on the surface of the substrate adjacent to the first soldering pad (31); a connecting pattern (34, 35) on the surface of the substrate for connecting the first and second soldering pads, the connecting pattern being made of an electric conductor wettable with a solder; and a solder dam (16) on the connecting pattern between the first and second soldering pads, characterised in that the solder dam (16) is made of a metal or a metal alloy or compound not wettable with a solder.
Claim 3
Dependent Claim
28 words
An assembly according to claim 1, wherein the first and second soldering pads (31, 33) are made of one of the group consisting of gold, silver, and nickel.
Claim 4
Dependent Claim
31 words
An assembly according to claim 1 or claim 2, wherein the solder dam (16) is made of one of the group consisting of titanium, chromium, ruthenium, rhodium molybdenum, tungsten, and titanium-nickel.
Claim 5
Dependent Claim
15 words
An assembly according to claim 3, wherein the solder dam (16) is titanium-nickel intermetallic compound.
Claim 6
Dependent Claim
46 words
An assembly according to any of the preceding claims, further comprising a first solder having a first melting point on the first soldering pad (31) and a second solder having a second melting point lower than the first melting point on the second soldering pad (33).
Claim 7
Dependent Claim
18 words
An assembly according to claim 5, wherein the first solder is gold-tin and the second solder is tin.
Claim 8
Dependent Claim
24 words
An assembly according to claim 5 or claim 6, further comprising a pin (42) soldered to the first soldering pad by the first solder.
Claim 9
Dependent Claim
17 words
An assembly according to any of the preceding claims, wherein the substrate includes an interconnecting line (3).
Claim 10
Dependent Claim
207 words
A process for manufacturing a multi-layer ceramic substrate assembly, the method comprising the steps of: preparing a multi-layer ceramic substrate (1); forming a pattern of a first electric conductor metal on a surface of the substrate, the pattern including first, second and third portions, the first and second portions being connected by the third portion in the pattern, the first portion of the pattern being electrically connected with a conductor (2), and the first electric conductor metal being wettable with a solder; forming a first soldering pad (31) of a second electric conductor metal on the first portion of the pattern; forming a second soldering pad (33) of a third electric conductor metal on the second portion of the pattern; entirely covering the first electric conductor metal pattern with a metal (41); reacting the metal (41) selectively with the first electric conductor metal at the third portion of the pattern to form a metal alloy or compound at that point; and selectively etching the metal (41) remaining at least on the first and second portions but not on the metal alloy or compound, wherein the first and second soldering pads are wettable with a solder and the metal alloy or compound is not wettable with a solder.
Claim 11
Dependent Claim
207 words
A process for manufacturing a multi-layer ceramic substrate assembly, the method comprising the steps of: preparing a multi-layer ceramic substrate (1); forming a pattern of a first electric conductor metal on a surface of the substrate, the pattern including first, second and third portions, the first and second portions being connected by the third portion in the pattern, the first portion of the pattern being electrically connected with a conductor (2), and the first electric conductor metal being wettable with a solder; forming a first soldering pad (31) of a second electric conductor metal on the first portion of the pattern; forming a second soldering pad (33) of a third electric conductor metal on the second portion of the pattern; entirely covering the first electric conductor metal pattern with a metal (41); reacting the metal (41) selectively with the first electric conductor metal at the third portion of the pattern to form a metal alloy or compound at that point; and selectively etching the metal (41) remaining at least on the first and second portions but not on the metal alloy or compound, wherein the first and second soldering pads are wettable with a solder and the metal alloy or compound is not wettable with a solder.
Claim 12
Dependent Claim
61 words
A process according to claim 9, wherein the second and third conductor metals are chosen from the group consisting of gold and alloys thereof, the first conductor metal is nickel, and the metal (41) covering the first electric conductor metal pattern is titanium, the metal alloy or compound formed at the third portion of the pattern being a titanium-nickel intermetallic compound.
Claim 13
Dependent Claim
50 words
A process according to claim 9 or claim 10, further comprising the step of bonding a first solder having a first melting point on the first soldering pad (31) and a second solder having a second melting point lower than the first melting point on the second soldering pad (33).
Claim 14
Dependent Claim
18 words
A process according to claim 11, wherein the first solder is gold-tin and the second solder is tin.
Claim 15
Dependent Claim
27 words
A process according to claim 11 or claim 12, further comprising the step of soldering a pin (42) to the first soldering pad by the first solder.
Claim 16
Dependent Claim
29 words
A process according to any of claims 9 to 13, wherein the second soldering pad is used for modification of an electric circuit in the multi-layer ceramic substrate assembly.
Claim 17
Dependent Claim
39 words
A process according to any of claims 9 to 14, further comprising the step of forming a body conductor copper layer (38) on the multi-layer ceramic layer, followed by forming the nickel pattern on the body conductor copper layer.
Claim 18
Dependent Claim
28 words
A process according to any of claims 9 to 15, further comprising the step of forming an insulating layer (39) on the surface of the multi-layer ceramic layer.
References Cited (Backward Citations)
No citation records indexed.
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