Patent US5539153A successfully refreshed from Google Patents.
US5539153A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of bumping substrates by contained paste deposition
Assignee: HP Inc
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Filing: 1994-08-08
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Granted: 1996-07-23
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Expires: 2014-08-08
Abstract
Abstract A solder bump is stenciled into a substrate, providing bumped substrate at pitches below 400 microns. The solder is applied through stencil/mask and paste method; the mask, however, remains attached to the substrate during reflow. Pitches of greater than 400 microns may also be obtained through the invention. The invention further provides for generation of uniform, controllable volume metal balls
Inventors
- 👤 Matthew K. Schwiebert
- 👤 Donald T. Campbell
- 👤 Matthew Heydinger
- 👤 Robert E. Kraft
- 👤 Hubert A. Vander Plas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:03
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/099; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/341; H05K3/3431; H05K3/3436; H05K3/3465; H05K3/3485; H10W72/00; H10W72/20; H10W72/30; H10W74/00; H10W74/01; H10W74/012; H10W74/10; H10W74/15; H10W90/00; H10W90/701; H05K2201/00; H05K2201/09; H05K2201/09209; H05K2201/09372; H05K2201/094; H05K2201/09654; H05K2201/09781; H05K2201/10; H05K2201/10431; H05K2201/10568; H05K2201/10613; H05K2201/10621; H05K2201/10734; H05K2201/20; H05K2201/2036; H05K2203/00; H05K2203/04; H05K2203/043; H05K2203/05; H05K2203/0562; H05K2203/0568; H05K2203/07; H05K2203/0756; H05K2203/0769; H05K3/10; H05K3/12; H05K3/1216; H05K3/346; H10W72/01; H10W72/011; H10W72/0112; H10W72/012; H10W72/01204; H10W72/01221; H10W72/01223; H10W72/01225; H10W72/01251; H10W72/01255; H10W72/071; H10W72/072; H10W72/07251; H10W72/07253; H10W72/073; H10W72/07321; H10W72/07327; H10W72/231; H10W72/237; H10W72/241; H10W72/251; H10W72/351; H10W72/352; H10W72/851; H10W72/853; H10W72/856; H10W72/90; H10W72/921; H10W72/923; H10W72/951; H10W72/952; H10W90/721; H10W90/724; H10W90/731; H10W90/734; H10W90/751; H10W90/756; Y; Y02; Y02P; Y02P70/00; Y02P70/50; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/4913
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
79 words
A method for forming solder bumps directly on a substrate having a plurality of wettable pads comprising the steps of: positioning a non-wettable metal mask on the substrate such that a plurality of apertures in the mask align with the pads; applying solder paste to the metal mask such that the solder paste loads the mask apertures; reflowing the solder paste to form solder bumps on the pads; and removing the metal mask after formation of the solder bumps.
Claim 2
Independent Claim
79 words
A method for forming solder bumps directly on a substrate having a plurality of wettable pads comprising the steps of: positioning a non-wettable metal mask on the substrate such that a plurality of apertures in the mask align with the pads; applying solder paste to the metal mask such that the solder paste loads the mask apertures; reflowing the solder paste to form solder bumps on the pads; and removing the metal mask after formation of the solder bumps.
Claim 3
Dependent Claim
17 words
A method as in claim 1 further comprising the step of cleaning the metal mask after removal.
Claim 4
Dependent Claim
18 words
A method as in claim 1 further comprising the step of inspecting the substrate/paste/mask assembly prior to reflow.
Claim 5
Dependent Claim
20 words
A method as in claim 3 further comprising the step of adding additional paste to untilled mask apertures after inspection.
Claim 6
Dependent Claim
19 words
A method as in claim 1 further comprising the step of inspecting the substrate/solder bump assembly after mask removal.
Claim 7
Dependent Claim
21 words
A method as in claim 5 further comprising the step of replacing missing bumps on the substrate/solder bump assembly after inspection.
Claim 8
Dependent Claim
21 words
A method as in claim 5 further comprising the step of repairing damaged bumps on the substrate/solder bump assembly after inspection.
Claim 9
Dependent Claim
17 words
A method as in claim 1 wherein the solder paste contains metal powder in a flux vehicle.
Claim 10
Dependent Claim
32 words
A method as in claim 1 wherein the solder paste contains an alloy of at least one metal that can be made into a powder and a flux vehicle for said powder.
Claim 11
Dependent Claim
17 words
A method as in claim 1 wherein the solder paste contains an 63 Sn 37 Pb alloy.
Claim 12
Dependent Claim
27 words
A method as in claim 1, wherein the coefficient of thermal expansion of the mask is substantially similar to the coefficient of thermal expansion of the substrate.
Claim 13
Dependent Claim
40 words
A method as in claim 1 wherein the mask is attached to the substrate in a manner that allows lateral excursion of the mask and substrate during reflow such that alignment of the mask apertures and the pads is maintained.
Claim 14
Dependent Claim
58 words
A method as in claim 1 wherein the substrate has a first surface and a second surface, the second surface being opposite to the first surface, and the step of positioning the metal mask on the substrate includes situating the mask on the first surface of the substrate and situating magnets on the second surface of the surface.
Claim 15
Dependent Claim
19 words
A method as in claim 13 wherein the magnets are capable of withstanding the heat from the reflow step.
Claim 16
Dependent Claim
11 words
A method as in claim 13 wherein the magnets contain AlNiCo.
Claim 17
Dependent Claim
19 words
A method as in claim 1 wherein the bumps have pitches in the range of 150 to 350 microns.
Claim 18
Dependent Claim
35 words
A method as in claim 1 wherein the apertures are cylindrical such that V paste =(πL 2 t)/4 where V paste is the required aperture volume, L is aperture size and t is mask thickness.
Claim 19
Dependent Claim
20 words
A method as in claim 1 wherein the metal mask is composed of 75-100 micron thick tension-leveled and sheeted alloy.
Claim 20
Independent Claim
141 words
A method for electrically connecting a first substrate having a plurality of wettable pads to a second substrate having a plurality of wettable pads comprising the steps of: forming solder bumps on the first substrate by a method comprising the steps of: attaching a non-wettable metal stencil mask having a plurality of apertures on the substrate such that the mask apertures are in alignment with the pads; applying solder paste to the metal mask such that the solder paste loads the mask apertures; reflowing the solder paste to form solder bumps on the pads; and removing the metal mask after forming the solder bumps; positioning the solder bumps formed on the first substrate in registry with the wettable pads of the second substrate; and reflowing the solder bumps to form an electrical connection between the first substrate and the second substrate.
Claim 21
Independent Claim
141 words
A method for electrically connecting a first substrate having a plurality of wettable pads to a second substrate having a plurality of wettable pads comprising the steps of: forming solder bumps on the first substrate by a method comprising the steps of: attaching a non-wettable metal stencil mask having a plurality of apertures on the substrate such that the mask apertures are in alignment with the pads; applying solder paste to the metal mask such that the solder paste loads the mask apertures; reflowing the solder paste to form solder bumps on the pads; and removing the metal mask after forming the solder bumps; positioning the solder bumps formed on the first substrate in registry with the wettable pads of the second substrate; and reflowing the solder bumps to form an electrical connection between the first substrate and the second substrate.
Claim 22
Dependent Claim
17 words
A method as in claim 19 further comprising the step of cleaning the metal mask after removal.
Claim 23
Dependent Claim
18 words
A method as in claim 19 further comprising the step of inspecting the substrate/paste/mask assembly prior to reflow.
Claim 24
Dependent Claim
20 words
A method as in claim 21 further comprising the step of adding additional paste to unfilled mask apertures after inspection.
Claim 25
Dependent Claim
19 words
A method as in claim 19 further comprising the step of inspecting the substrate/solder bump assembly after mask removal.
Claim 26
Dependent Claim
21 words
A method as in claim 23 further comprising the step of replacing missing bumps on the substrate/solder bump assembly after inspection.
Claim 27
Dependent Claim
21 words
A method as in claim 23 further comprising the step of repairing damaged bumps on the substrate/solder bump assembly after inspection.
Claim 28
Dependent Claim
53 words
A method as in claim 19 further comprising the step of adding bumps after metal mask removal through positioning one or more bumps on a carrier medium near the wettable pads of the first substrate such that the bump is attracted to and moves onto the wettable pad, detaching from the carrier medium.
Claim 29
Dependent Claim
19 words
A method as in claim 19 wherein the bumps have pitches in the range of 150 to 350 microns.
Claim 30
Dependent Claim
35 words
A method as in claim 19 wherein the apertures are cylindrical such that V paste =(πL 2 t)/4 where V paste is the required aperture volume, L is aperture size and t is mask thickness.
Claim 31
Dependent Claim
20 words
A method as in claim 19 wherein the metal mask is composed of 75-100 micron thick tension-leveled and sheeted alloy.
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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) | 1999-07-23 | 2000-01-22 | 2000-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-23 | 2004-01-22 | 2004-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-23 | 2008-01-22 | 2008-07-23 | $7700.00 | Window Closed / Lapsed |