Patent US5463191A successfully refreshed from Google Patents.
US5463191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit board having an improved fine pitch ball grid array and method of assembly therefor
Assignee: Dell USA LP
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Filing: 1994-03-14
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Granted: 1995-10-31
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Expires: 2014-03-14
Abstract
Abstract A circuit board design featuring a fine pitch ball grid array ("BGA") having a simplified construction. The circuit board comprises: (1) an insulating substrate, the substrate having a via therethrough, (2) a conductive layer located over the substrate, the via passing through the layer and laterally uninterrupted through the circuit board, (3) a first solder having a first melting point located within and substantially blocking the via and (4) a second solder having a second melting point located over the blocked via, the second melting point lower than the first melting point, the first solder remaining substantially solid and preventing the second solder from substantially entering the via when the first and second solders are heated to a temperature between the first and second melting points. The present invention eliminates precision drilling required by current blind via BGA pad designs.
Inventors
- 👤 James S. Bell
- 👤 Deepak Swamy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:22
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/0094; H05K1/00; H05K1/02; H05K1/11; H05K1/111; H05K1/112; H05K1/113; H05K3/30; H05K3/32; H05K3/34; H05K3/346; H05K2201/00; H05K2201/09; H05K2201/09209; H05K2201/095; H05K2201/09572; H05K2201/10; H05K2201/10613; H05K2201/10621; H05K2201/10734; H05K2201/10954; H05K2201/10992; H05K3/341; H05K3/3431; H05K3/40; H05K3/42; H05K3/429
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
106 words
A circuit board, comprising: an insulating substrate, said substrate having a via therethrough; a conductive layer located over said substrate, said via passing through said layer and laterally uninterrupted through said circuit board; a first solder having a first melting point located within and substantially blocking said via; and a second solder having a second melting point located over said blocked via, said second melting point lower than said first melting point, said first solder remaining substantially solid and preventing said second solder from substantially entering said via when said first and second solders are heated to a temperature between said first and second melting points.
Claim 2
Dependent Claim
106 words
A circuit board, comprising: an insulating substrate, said substrate having a via therethrough; a conductive layer located over said substrate, said via passing through said layer and laterally uninterrupted through said circuit board; a first solder having a first melting point located within and substantially blocking said via; and a second solder having a second melting point located over said blocked via, said second melting point lower than said first melting point, said first solder remaining substantially solid and preventing said second solder from substantially entering said via when said first and second solders are heated to a temperature between said first and second melting points.
Claim 3
Dependent Claim
25 words
The circuit board as recited in claim 1 further comprising a conductive coating located between said first solder and an inner surface of said via.
Claim 4
Dependent Claim
31 words
The circuit board as recited in claim 1 further comprising a solder mask located over said conductive layer, said solder mask constraining a location of said second solder over said via.
Claim 5
Dependent Claim
20 words
The circuit board as recited in claim 1 wherein said conductive layer is an outer layer of said circuit board.
Claim 6
Dependent Claim
18 words
The circuit board as recited in claim 1 wherein said substrate and said conductive layer are substantially planar.
Claim 7
Dependent Claim
16 words
The circuit board as recited in claim 1 wherein said first solder is a tin-lead composition.
Claim 8
Dependent Claim
16 words
The circuit board as recited in claim 1 wherein said second solder is a tin-lead composition.
Claim 9
Dependent Claim
15 words
The circuit board as recited in claim 1 wherein said conductive layer is copper metal.
Claim 10
Dependent Claim
24 words
The circuit board as recited in claim 1 wherein said first solder has a meniscus within said via, said second solder contacting said meniscus.
Claim 11
Dependent Claim
20 words
The circuit board as recited in claim 1 wherein said second solder constitutes a pad for receiving an electrical contact.
Claim 12
Dependent Claim
142 words
A circuit board, comprising: a substantially planar insulating substrate, said substrate having a via therethrough; a substantially planar conductive layer located over said substrate and forming an outer layer of said circuit board, said via passing through said layer and laterally uninterrupted through said circuit board, said via having a conductive coating located on an inner surface thereof; a first solder having a first melting point located within and substantially blocking said via; and a second solder having a second melting point located over said blocked via, said second melting point lower than said first melting point, said first solder remaining substantially solid and preventing said second solder from substantially entering said via when said first and second solders are heated to a temperature between said first and second melting points, said second solder constituting a pad for receiving an electrical contact.
Claim 13
Dependent Claim
142 words
A circuit board, comprising: a substantially planar insulating substrate, said substrate having a via therethrough; a substantially planar conductive layer located over said substrate and forming an outer layer of said circuit board, said via passing through said layer and laterally uninterrupted through said circuit board, said via having a conductive coating located on an inner surface thereof; a first solder having a first melting point located within and substantially blocking said via; and a second solder having a second melting point located over said blocked via, said second melting point lower than said first melting point, said first solder remaining substantially solid and preventing said second solder from substantially entering said via when said first and second solders are heated to a temperature between said first and second melting points, said second solder constituting a pad for receiving an electrical contact.
Claim 14
Dependent Claim
31 words
The circuit board as recited in claim 1, further comprising a solder mask located over said conductive layer, said solder mask constraining a location of said second solder over said via.
Claim 15
Dependent Claim
16 words
The circuit board as recited in claim 11, wherein said first solder is a tin-lead composition.
Claim 16
Dependent Claim
16 words
The circuit board as recited in claim 11 wherein said second solder is a tin-lead composition.
Claim 17
Dependent Claim
15 words
The circuit board as recited in claim 11 wherein said conductive layer is copper metal.
Claim 18
Dependent Claim
24 words
The circuit board as recited in claim 11 wherein said first solder has a meniscus within said via, said second solder contacting said meniscus.
Claim 19
Dependent Claim
30 words
The circuit board as recited in claim 11 further comprising a plurality of alternating substrate and conductive layers forming a plurality of spaced-apart conductive patterns for communication of electrical signals.
Claim 20
Dependent Claim
20 words
The circuit board as recited in claim 11 wherein said pad is a portion of a ball grid array (BGA).
Claim 21
Dependent Claim
34 words
The circuit board as recited in claim 11 further comprising a second conductive layer located under said substrate, said conductive coating electrically coupling said conductive layer over said substrate to said second conductive layer.
Claim 22
Dependent Claim
21 words
The circuit board as recited in claim 11 wherein said circuit board is adapted to hold components of a computer system.
Claim 23
Dependent Claim
191 words
A multi-layer circuit board adapted to hold components of a computer system, comprising: a substantially planar insulating substrate, said substrate having a via therethrough; a first substantially planar copper metal conductive layer located over said substrate and forming an outer layer of said circuit board; a second substantially planar copper metal conductive layer located under said substrate, said via passing through said first and second layers and laterally uninterrupted through said circuit board, said via having a conductive coating located on an inner surface thereof, said conductive coating electrically coupling said first conductive layer to said second conductive layer; a first tin-lead solder having a first melting point located within and substantially blocking said via; and a second tin-lead solder having a second melting point located over said blocked via, said second melting point lower than said first melting point, said second tin-lead solder remaining substantially solid and preventing said first tin-lead solder from substantially entering said via when said first tin-lead and said second tin-lead solders are heated to a temperature between said first and second melting points, said second tin-lead solder constituting a pad for receiving an electrical contact.
Claim 24
Dependent Claim
191 words
A multi-layer circuit board adapted to hold components of a computer system, comprising: a substantially planar insulating substrate, said substrate having a via therethrough; a first substantially planar copper metal conductive layer located over said substrate and forming an outer layer of said circuit board; a second substantially planar copper metal conductive layer located under said substrate, said via passing through said first and second layers and laterally uninterrupted through said circuit board, said via having a conductive coating located on an inner surface thereof, said conductive coating electrically coupling said first conductive layer to said second conductive layer; a first tin-lead solder having a first melting point located within and substantially blocking said via; and a second tin-lead solder having a second melting point located over said blocked via, said second melting point lower than said first melting point, said second tin-lead solder remaining substantially solid and preventing said first tin-lead solder from substantially entering said via when said first tin-lead and said second tin-lead solders are heated to a temperature between said first and second melting points, said second tin-lead solder constituting a pad for receiving an electrical contact.
Claim 25
Dependent Claim
31 words
The circuit board as recited in claim 21 further comprising a solder mask located over said conductive layer, said solder mask constraining a location of said tin-lead solder over said via.
Claim 26
Dependent Claim
24 words
The circuit board as recited in claim 21 wherein said tin-bismuth solder has a meniscus within said via, said tin-lead solder contacting said meniscus.
Claim 27
Dependent Claim
30 words
The circuit board as recited in claim 21 further comprising a plurality of alternating substrate and conductive layers forming a plurality of spaced-apart conductive patterns for communication of electrical signals.
Claim 28
Dependent Claim
20 words
The circuit board as recited in claim 21 wherein said pad is a portion of a ball grid array (BGA).
References Cited (Backward Citations)
US5180440A
Cited
US5147084A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-10-30 | 1999-05-01 | 1999-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-30 | 2003-05-01 | 2003-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-30 | 2007-05-01 | 2007-10-31 | $7700.00 | Window Closed / Lapsed |