US5872400A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High melting point solder ball coated with a low melting point solder
Assignee: Ultratech Inc
•
Filing: 1997-06-25
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Granted: 1999-02-16
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Expires: 2017-06-25
Abstract
Abstract A solder ball structure having a first object and least one solder ball, each solder ball having an outer surface, top and a bottom and comprising a non-eutectic admixture of solder. The solder ball structure also having at least one BLM, each BLM having a top and a bottom and the top of each BLM in contact with the bottom of one of the at least one solder ball, each BLM containing a solder having a melting point sufficiently lower than the melting point of the corresponding solder ball such that each BLM can reflow without a significant portion of the corresponding solder ball reflowing, the bottom of each at least one BLM in electrical communication with the first object. The solder ball structure further having at least one solder ball coating, each coating in contact with one of the at least one solder ball over at least the portion of the solder ball surface not in contact with the corresponding BLM; each coating having a melting point sufficiently lower than the melting point of the corresponding solder ball such that each coating can reflow without a significant portion of the corresponding solder ball reflowing.
Inventors
- 👤 Brian D. Chapman
- 👤 James J. Petrone
- 👤 Wai Mon Ma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:50
CPC Classifications
H; H10; H10W; H10W90/00; H10W90/701; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/341; H05K3/3431; H05K3/3436; H05K2201/00; H05K2201/10; H05K2201/10613; H05K2201/10954; H05K2201/10992; H05K2201/20; H05K2201/2081; H05K2203/00; H05K2203/04; H05K2203/041; H10W72/00; H10W72/01; H10W72/012; H10W72/01221; H10W72/01225; Y; Y02; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
193 words
A solder ball structure comprising: a first object; at least one solder ball having an outer surface, a top and a bottom and comprising a non-eutectic admixture of solder; at least one ball limiting metallurgy structure (BLM) containing a solder having a melting point sufficiently lower than the melting point of the corresponding solder ball such that the BLM can reflow without a significant portion of the corresponding solder ball reflowing, and wherein the BLM has a top and a bottom and wherein the top of at least one of the BLM is in contact with the bottom of one of the at least one solder ball, and wherein the BLM is in electrical communication with the first object; and at least one solder ball coating, each at least one coating in contact with one of the at least one solder ball over at least the portion of the solder ball surface not in contact with the corresponding BLM; wherein the coating has a melting point sufficiently lower than the melting point of the corresponding solder ball such that each coating can reflow without a significant portion of the corresponding solder ball reflowing.
Claim 2
Dependent Claim
193 words
A solder ball structure comprising: a first object; at least one solder ball having an outer surface, a top and a bottom and comprising a non-eutectic admixture of solder; at least one ball limiting metallurgy structure (BLM) containing a solder having a melting point sufficiently lower than the melting point of the corresponding solder ball such that the BLM can reflow without a significant portion of the corresponding solder ball reflowing, and wherein the BLM has a top and a bottom and wherein the top of at least one of the BLM is in contact with the bottom of one of the at least one solder ball, and wherein the BLM is in electrical communication with the first object; and at least one solder ball coating, each at least one coating in contact with one of the at least one solder ball over at least the portion of the solder ball surface not in contact with the corresponding BLM; wherein the coating has a melting point sufficiently lower than the melting point of the corresponding solder ball such that each coating can reflow without a significant portion of the corresponding solder ball reflowing.
Claim 3
Dependent Claim
13 words
The structure according to claim 1 wherein the BLM is a eutectic solder.
Claim 4
Dependent Claim
18 words
The structure according to claim 1 wherein the solder ball comprises 90% tin and 10% lead in admixture.
Claim 5
Dependent Claim
13 words
The structure according to claim 1 wherein the coating comprises an eutectic solder.
Claim 6
Dependent Claim
16 words
The structure according to claim 1 wherein the BLM and the coating comprise an eutectic solder.
Claim 7
Dependent Claim
16 words
The structure according to claim 5 wherein the solder ball is encapsulated in the eutectic solder.
Claim 8
Dependent Claim
23 words
The structure according to claim 6 wherein the thickness of the eutectic solder on the top of the solder ball is 2.5 mils.
Claim 9
Dependent Claim
16 words
The structure according to claim 1 wherein the first object is a ceramic ball grid array.
Claim 10
Dependent Claim
31 words
The structure according to claim 8 wherein each at least one BLM is in communication with a single ceramic ball grid array capable of electrically communicating with a plurality of BLMs.
Claim 11
Dependent Claim
147 words
A solder ball structure for a ceramic ball grid array comprising: a plurality of solder balls having an outer surface, a top and a bottom and comprising 90% Pb and 10% Sn in admixture; a plurality of BLMs having a top side and a bottom side, and wherein the bottom of the solder balls is in contact with the top side of one BLM comprising 37% Pb and 63% Sn in admixture, and the BLMs in electrical communication with the ceramic ball grid array on the bottom side; and a plurality of solder ball coatings comprising 37% Pb and 63% Sn in admixture, wherein the solder balls are in contact with one coating over substantially all of the portion of the solder ball surface not in contact with the BLM, and wherein the thickness of the coating on the top of the solder ball is 2.5 mils.
Claim 12
Dependent Claim
147 words
A solder ball structure for a ceramic ball grid array comprising: a plurality of solder balls having an outer surface, a top and a bottom and comprising 90% Pb and 10% Sn in admixture; a plurality of BLMs having a top side and a bottom side, and wherein the bottom of the solder balls is in contact with the top side of one BLM comprising 37% Pb and 63% Sn in admixture, and the BLMs in electrical communication with the ceramic ball grid array on the bottom side; and a plurality of solder ball coatings comprising 37% Pb and 63% Sn in admixture, wherein the solder balls are in contact with one coating over substantially all of the portion of the solder ball surface not in contact with the BLM, and wherein the thickness of the coating on the top of the solder ball is 2.5 mils.
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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) | 2002-02-15 | 2002-08-17 | 2003-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-02-15 | 2006-08-17 | 2007-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-02-15 | 2010-08-17 | 2011-02-16 | $7700.00 | Window Closed / Lapsed |