Patent US4739142A successfully refreshed from Google Patents.
US4739142A
Expired / Lapsed
US
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Method of producing a wire bonding ball
Assignee: Mitsubishi Electric Corp
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Filing: 1986-12-10
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Granted: 1988-04-19
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Expires: 2006-12-10
Abstract
Abstract A method of producing a wire bonding ball for ball bonding a metal wire to an electrode of a semiconductor chip involves producing a ball by melting the top end of the metal wire by a discharge which is conducted by applying a high voltage between said metal wire and a discharge electrode in an inactive gas ambient. The metal wire is at a positive voltage said the discharge electrode is at a negative voltage, respectively. Next, a latter period discharge is conducted by inverting the voltage polarities of the discharge electrode elements. The metal wire used is a material capable of being oxidated.
Inventors
- 👤 Jitsuho Hirota
- 👤 Kazumichi Machida
- 👤 Masaaki Shimotomai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:41
CPC Classifications
B; B23; B23K; B23K20/00; B23K20/002; B23K20/004; B23K20/005; B23K20/007; H; H10; H10W; H10W72/00; H10W72/01; H10W72/015; H10W72/01551; H10W72/071; H10W72/0711; H10W72/07141; H10W72/075; H10W72/07511; H10W72/07541; H10W72/50; H10W72/531; H10W72/536; H10W72/551; H10W72/552; H10W72/5522; H10W72/5524; H10W72/5525; H10W72/59; H10W72/90; H10W72/951; H10W72/952; H10W90/00; H10W90/701; H10W90/751; H10W90/756
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
182 words
A method for producing a wire bonding ball for use in ball bonding a metal wire to an electrode of a semiconductor chip comprising the steps of: providing a metal wire and a discharge electrode, said metal wire being located proximate to said electrode, said metal wire and said discharge electrode being located in an inactive ambient gas and said metal wire being comprised of material which is capable of being oxidated but which oxidation is avoided as the metal wire is located in said inactive ambient gas; applying a high voltage between said metal wire and said discharge electrode, said metal wire is placed at a positive voltage while said discharge electrode is placed at a negative voltage; melting an end portion of said wire due to said applying a high voltage, said melting forming a generally, spherical shape at said end portion; switching the voltage only once such that the metal wire is placed at a negative voltage and the discharge electrode is placed at a positive voltage; and cleaning said generally, spherical shape due to said switching the voltage.
Claim 2
Independent Claim
182 words
A method for producing a wire bonding ball for use in ball bonding a metal wire to an electrode of a semiconductor chip comprising the steps of: providing a metal wire and a discharge electrode, said metal wire being located proximate to said electrode, said metal wire and said discharge electrode being located in an inactive ambient gas and said metal wire being comprised of material which is capable of being oxidated but which oxidation is avoided as the metal wire is located in said inactive ambient gas; applying a high voltage between said metal wire and said discharge electrode, said metal wire is placed at a positive voltage while said discharge electrode is placed at a negative voltage; melting an end portion of said wire due to said applying a high voltage, said melting forming a generally, spherical shape at said end portion; switching the voltage only once such that the metal wire is placed at a negative voltage and the discharge electrode is placed at a positive voltage; and cleaning said generally, spherical shape due to said switching the voltage.
Claim 3
Dependent Claim
26 words
A method of producing a wire bonding ball as defined in claim 1, further including the step of using a copper wire for said metal wire.
Claim 4
Dependent Claim
43 words
The method for producing as recited in claim 1 wherein said switching includes the steps of; using less current for said voltage after said switching; and applying the lower voltage for a period of time less than said applying of said high voltage.
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) | 1991-04-19 | 1991-10-19 | 1992-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-19 | 1995-10-19 | 1996-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-19 | 1999-10-19 | 2000-04-19 | $7700.00 | Window Closed / Lapsed |