US5168346A
Expired / Lapsed
US
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Method and apparatus for isolation of flux materials in flip-chip manufacturing
Assignee: Fiix Inc
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Filing: 1991-10-11
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Granted: 1992-12-01
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Expires: 2011-10-11
Abstract
Abstract A preformed planar structure is interposed between the chip(s) and the substrate in a flip-chip structure, and establishes a minimum gap between the chip(s) and the substrate. Liquid flux may be applied to the preformed planar structure in order that flux is selectively applied to the solder balls (pads) on the chip and the substrate. The preformed planar structure may be provided with through holes in registration with the solder balls on the chip(s) and the substrate. In this case, liquid flux selectively fills the through holes for delivery to the solder balls during soldering. The through holes also aid in maintaining registration of the chip(s) and the substrate. The through holes may be sized to establish a predetermined mechanical structure of solder joints formed by the solder balls when fused together. The preformed planar structure has a planar core and opposing planar faces. The core is formed of thermosetting organic resin, such as polyimide, or non-organic material such as alumina, polished sapphire, beryllium oxide, aluminum nitride or aluminum. The planar faces of the preformed planar structure are formed of thermoplastic resin or thermosetting material, such as polyacetal, expoxide resin or polystyrene. The preformed planar structure tends to draw the chip(s) together to the substrate, establishing a flip-chip structure of mechanical integrity. The preformed planar structure has a thickness of 5-50 microns, preferably on the order of 20-30 microns. Method and apparatus are disclosed.
Inventors
- 👤 Nicholas F. Pasch
- 👤 Vahak K. Sahakian
- 👤 Conrad J. Dell'Oca
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:50
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70425; G03F7/70433; H; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/341; H05K3/3431; H05K3/3436; H10; H10W; H10W72/00; H10W72/30; H10W74/00; H10W74/01; H10W74/012; H10W74/10; H10W74/15; H05K2201/00; H05K2201/10; H05K2201/10227; H05K2201/10424; H05K2201/20; H05K2201/2036; H05K2203/00; H05K2203/16; H05K2203/167; H05K3/303; H05K3/3489; H10W72/071; H10W72/072; H10W72/07231; H10W72/07236; H10W72/073; H10W72/851; H10W72/853; H10W72/856; H10W90/00; H10W90/701; H10W90/721; H10W90/724; Y; Y02; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
130 words
A flip-chip structure comprising: a chip having first solder balls on a face thereof; a substrate having corresponding second solder balls on a face thereof; and a separate and distinct preformed planar structure disposed between the chip and the substrate, having a periphery and two opposite faces, one face in contact with the chip and the opposite face in contact with the substrate; cutouts in the periphery of the preformed planar structure, extending from the one face to the opposite face; and solder joints consisting essentially of the first solder balls and corresponding second solder balls fused to one another within the cutouts; wherein the cutouts are sized to establish a predetermined mechanical structure of the solder joints formed by the first solder balls and the second corresponding solder balls.
Claim 2
Dependent Claim
130 words
A flip-chip structure comprising: a chip having first solder balls on a face thereof; a substrate having corresponding second solder balls on a face thereof; and a separate and distinct preformed planar structure disposed between the chip and the substrate, having a periphery and two opposite faces, one face in contact with the chip and the opposite face in contact with the substrate; cutouts in the periphery of the preformed planar structure, extending from the one face to the opposite face; and solder joints consisting essentially of the first solder balls and corresponding second solder balls fused to one another within the cutouts; wherein the cutouts are sized to establish a predetermined mechanical structure of the solder joints formed by the first solder balls and the second corresponding solder balls.
Claim 3
Dependent Claim
34 words
A flip-chip structure according to claim 1, wherein the preformed planar structure has a planar core with two opposing faces and layers of material formed on the two opposing faces of the planar core.
Claim 4
Dependent Claim
48 words
A flip-chip structure according to claim 2, wherein the layers of material function as means for drawing the chip together to the substrate when the chip and the substrate are subjected to elevated temperatures for effecting soldering of the first solder balls to the corresponding second solder balls.
Claim 5
Dependent Claim
16 words
A flip-chip structure according to claim 2, wherein the core is formed of thermosetting organic resin.
Claim 6
Dependent Claim
15 words
A flip-chip structure according to claim 2, wherein the core is formed of non-organic material.
Claim 7
Dependent Claim
14 words
A flip-chip structure according to claim 2, wherein the core is formed of polymide.
Claim 8
Dependent Claim
15 words
A flip-chip structure according to claim 2, wherein the core is formed of polished alumina.
Claim 9
Dependent Claim
15 words
A flip-chip structure according to claim 2, wherein the core is formed of polished sapphire.
Claim 10
Dependent Claim
15 words
A flip-chip structure according to claim 2, wherein the core is formed of beryllium oxide.
Claim 11
Dependent Claim
15 words
A flip-chip structure according to claim 2, wherein the core is formed of aluminum nitride.
Claim 12
Dependent Claim
14 words
A flip-chip structure according to claim 2, wherein the core is formed of aluminum.
Claim 13
Dependent Claim
15 words
A flip-chip structure according to claim 2, wherein the layers are formed of thermosetting material.
Claim 14
Dependent Claim
15 words
A flip-chip structure according to claim 2, wherein the layers are formed of thermoplastic resin.
Claim 15
Dependent Claim
14 words
A flip-chip structure according to claim 2, wherein the layers are formed of polyacetal.
Claim 16
Dependent Claim
15 words
A flip-chip structure according to claim 2, wherein the layers are formed of epoxide resin.
Claim 17
Dependent Claim
14 words
A flip-chip structure according to claim 2, wherein the layers are formed of polystyrene.
Claim 18
Dependent Claim
25 words
A flip-chip structure according to claim 1, wherein the preformed planar structure has a thickness establishing a predetermined gap between the chip and the substrate.
Claim 19
Dependent Claim
18 words
A flip-chip structure according to claim 17, wherein the thickness of the preformed planar structure is 5-50 microns.
Claim 20
Dependent Claim
18 words
A flip-chip structure according to claim 18, wherein the thickness of the preformed planar structure is 20-30 microns.
Claim 21
Dependent Claim
14 words
A flip-chip structure according to claim 1, further comprising: flux disposed within the cutouts.
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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) | 1995-12-01 | 1996-06-01 | 1996-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-12-01 | 2000-06-01 | 2000-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-12-01 | 2004-06-01 | 2004-12-01 | $7700.00 | Window Closed / Lapsed |