Patent US5773780A successfully refreshed from Google Patents.
US5773780A
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Method of severing bond wires and forming balls at their ends
Assignee: FormFactor Inc
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Filing: 1996-02-07
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Granted: 1998-06-30
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Expires: 2016-02-07
Abstract
Abstract The efficacy of electrical discharges for severing bond wires and/or for forming balls at the ends of bond wires (including bond wires already severed by alternative mechanisms) is improved by performing the electrical discharges in the presence of ultraviolet light. A "spark gap" is formed between an EFO electrode and the wire, one of which serves as the cathode of the spark gap. Preferably, the ultraviolet light is directed at the element serving as the cathode of the spark gap. Providing photoemission at the cathode element of the spark gap stabilizes arc/plasma formation and produces more reliable and predictable results. This technique may be used in conjunction with negative EFO systems or with positive EFO systems, and may benefit from either direct or field-assisted photoemission.
Inventors
- 👤 Benjamin N. Eldridge
- 👤 Gaetan L. Mathieu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:57
CPC Classifications
B; B23; B23K; B23K20/00; B23K20/002; B23K20/004; H; H05; H05K; H05K3/00; H05K3/22; H05K3/24; H05K3/30; H05K3/306; H05K3/308; H05K3/32; H05K3/325; H05K3/326; H05K3/34; H05K3/341; H05K3/3421; H05K3/3426; H05K3/40; H05K3/4007; H05K3/4015; H05K7/00; H05K7/02; H05K7/10; H05K7/1053; H05K7/1061; H05K7/1069; H10; H10P; H10P74/00; H10P74/23; H10W; H10W70/00; H10W70/099; H10W72/00; H10W72/071; H10W72/075; H10W74/00; H10W74/01; H10W74/012; H10W74/10; H10W74/15; H10W90/00; H10W90/701; B23K2101/00; B23K2101/36; B23K2101/40; C; C25; C25D; C25D21/00; C25D21/02; G; G01; G01R; G01R3/00; G01R31/00; G01R31/28; G01R31/2851; G01R31/2884; H01; H01R; H01R12/00; H01R12/50; H01R12/51; H01R12/52; H05K1/00; H05K1/02; H05K1/14; H05K1/141; H05K2201/00; H05K2201/03; H05K2201/0332; H05K2201/0388; H05K2201/0397; H05K2201/06; H05K2201/068; H05K2201/10; H05K2201/10227; H05K2201/1031; H05K2201/10318; H05K2201/10378; H05K2201/10613; H05K2201/10621; H05K2201/10719; H05K2201/10734; H05K2201/10742; H05K2201/1075; H05K2201/10757; H05K2201/10878; H05K2201/10886; H05K2201/10909; H05K2201/10946; H05K3/10; H05K3/20; H05K3/36; H05K3/368; H05K3/4092; H10W70/60; H10W70/67; H10W70/68; H10W70/682; H10W72/01; H10W72/012; H10W72/01221; H10W72/01225; H10W72/015; H10W72/01551; H10W72/0711; H10W72/07141; H10W72/072; H10W72/07231; H10W72/07236; H10W72/07502; H10W72/07511; H10W72/07531; H10W72/07532; H10W72/07551; H10W72/07554; H10W72/20; H10W72/251; H10W72/252; H10W72/50; H10W72/521; H10W72/522; H10W72/541; H10W72/547; H10W72/551; H10W72/552; H10W72/5522; H10W72/553; H10W72/555; H10W72/851; H10W72/853; H10W72/856; H10W90/20; H10W90/22; H10W90/721; H10W90/722; H10W90/751; H10W90/754; Y; Y02; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
116 words
Method of severing and forming balls at the end of bond wires, comprising: bonding a bond wire to a terminal of an electronic component with a capillary of a wire bonder; with an electrode disposed at or beyond an end of the capillary, causing a first electrical discharge to sever the bond wire so that a first portion of the bond wire is bonded to the electronic component and an end of a second portion of the bond wire extends from the end of the capillary of the wire bonder; and after causing the first electrical discharge, causing a second electrical discharge to form a ball at the end of the second portion of the wire.
Claim 2
Dependent Claim
116 words
Method of severing and forming balls at the end of bond wires, comprising: bonding a bond wire to a terminal of an electronic component with a capillary of a wire bonder; with an electrode disposed at or beyond an end of the capillary, causing a first electrical discharge to sever the bond wire so that a first portion of the bond wire is bonded to the electronic component and an end of a second portion of the bond wire extends from the end of the capillary of the wire bonder; and after causing the first electrical discharge, causing a second electrical discharge to form a ball at the end of the second portion of the wire.
Claim 3
Dependent Claim
22 words
A Method, according to claim 1, wherein: the first electrical discharge melts the bond wire, resulting in the two separated portions thereof.
Claim 4
Dependent Claim
32 words
Method, according to claim 1, wherein: the first electrical discharge severs the first portion so that a free end thereof is at a controlled height above a surface of the electronic component.
Claim 5
Dependent Claim
39 words
Method, according to claim 1, performed on a plurality of bond wires which are bonded to a plurality of terminals on the electronic component, further comprising: severing the plurality of bond wires with a plurality of first electrical discharges.
Claim 6
Dependent Claim
26 words
Method, according to claim 4, wherein: the plurality of first electrical discharges sever the plurality of first portions so that free ends (tips) thereof are coplanar.
Claim 7
Dependent Claim
50 words
Method, according to claim 1, further comprising: controlling an intensity of the first electrical discharge so as to be just sufficient to sever the bond wire, without causing balls of significant size to be formed at ends of either of the first or second portions of the severed bond wire.
Claim 8
Dependent Claim
26 words
Method, according to claim 6, further comprising: in a subsequent processing step, forming a ball on the end of the second portion of the bond wire.
Claim 9
Dependent Claim
41 words
Method, according to claim 6, further comprising: in a subsequent processing step, forming a ball on the end of the second portion of the bond wire without forming a ball on the end of the first portion of the bond wire.
Claim 10
Dependent Claim
22 words
Method, according to claim 1, further comprising: prior to generating the first electrical discharge, moving the capillary relative to the electronic component.
Claim 11
Dependent Claim
13 words
Method, according to claim 9, wherein: the capillary is moved approximately 0.5 mm.
Claim 12
Dependent Claim
32 words
Method, according to claim 1, further comprising: after bonding the bond wire to the electronic component and prior to causing the first electrical discharge, moving the capillary relative to the electronic component.
Claim 13
Dependent Claim
13 words
Method, according to claim 11, wherein: the capillary is moved approximately 0.5 mm.
Claim 14
Dependent Claim
26 words
Method, according to claim 11, further comprising: while severing the bond wire, illuminating at least one of the electrode and the bond wire with ultraviolet light.
Claim 15
Dependent Claim
23 words
Method, according to claim 13, further comprising: directing the ultraviolet light at the at least one of the electrode and the bond wire.
Claim 16
Dependent Claim
60 words
Method, according to claim 14, wherein: providing the first electrical discharge with an EFO electrode; the EFO electrode and the wire function, in use, as a spark gap, a one of the EFO electrode and the wire functioning as a cathode element of the spark gap; and the ultraviolet light is directed at the cathode element of the spark gap.
Claim 17
Dependent Claim
26 words
Method, according to claim 15, wherein: the cathode element is illuminated with light having sufficient energy to stimulate the production of photo-electrons at the cathode element.
Claim 18
Dependent Claim
34 words
Method, according to claim 16, wherein: the energy of the light is limiting to be below the absorption cutoff for any medium between a light source providing the light energy and the cathode element.
Claim 19
Dependent Claim
27 words
Method, according to claim 16, wherein: the cathode element has a work function; and the light energy is greater than the work function of the cathode element.
Claim 20
Dependent Claim
14 words
Method, according to claim 13, further comprising: flood-illuminating the electrode and the bond wire.
Claim 21
Dependent Claim
15 words
Method, according to claim 13, wherein: the light has a wavelength of 184 nanometers (nm).
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-06-29 | 2001-12-29 | 2002-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-29 | 2005-12-29 | 2006-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-29 | 2009-12-29 | 2010-06-30 | $7700.00 | Window Closed / Lapsed |