US4232440A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Contact structure for light emitting device
Assignee: AT&T Inc
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Filing: 1979-02-27
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Granted: 1980-11-11
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Expires: 1999-02-27
Abstract
Abstract A contact structure to the light emitting surface 19 of a light emitting device 10 having an array of small distributed contacts 14 is made by selectively depositing a larger area bonding pad 15 over a portion of the distributed contacts. The small contacts not covered by the bonding pad then are removed by sputter etching and contact to the device is made by wire bonding a lead 17 to the bonding pad.
Inventors
- 👤 John J. Bastek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:32
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/83; H10H20/831; H10H20/01; H10H20/032; H10H20/85; H10H20/857; H10W; H10W72/00; H10W72/50; H10W72/531; H10W72/536; H10W72/59; H10W72/90; H10W72/931; H10W72/932
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
122 words
The method of making a substantially ohmic low resistance contact to the light emitting surface 19 of a light emitting semiconductor device 10 comprising the steps of; (1) forming on said light emitting surface an array of small metallic contacts 14, (2) heating said device to alloy a portion of each said contact to said light emitting surface, (3) selectively depositing a large area metal bonding pad 15 on said light emitting surface and over a plurality of said small contacts, (4) subjecting the light emitting contact surface to sputter etching for a period of time sufficient to entirely remove the small contacts not covered by the bonding pad, and (5) attaching a wire lead to the surface of said bonding pad.
Claim 2
Independent Claim
122 words
The method of making a substantially ohmic low resistance contact to the light emitting surface 19 of a light emitting semiconductor device 10 comprising the steps of; (1) forming on said light emitting surface an array of small metallic contacts 14, (2) heating said device to alloy a portion of each said contact to said light emitting surface, (3) selectively depositing a large area metal bonding pad 15 on said light emitting surface and over a plurality of said small contacts, (4) subjecting the light emitting contact surface to sputter etching for a period of time sufficient to entirely remove the small contacts not covered by the bonding pad, and (5) attaching a wire lead to the surface of said bonding pad.
Claim 3
Independent Claim
142 words
The method of making a substantially ohmic low resistance contact to the light emitting surface of a light emitting semiconductor device which is of the III-V compound semiconductor type comprising the steps of (1) forming on said light emitting surface a regular array of small metallic contacts, (2) heating said device to alloy a portion of each said contact to said light emitting surface, (3) selectively depositing a large area metal bonding pad on said light emitting surface and over a plurality of said small contacts, said pad having a thickness at least about an order of magnitude greater than the thickness of small contacts, (4) subjecting the contact surface to sputter etching for a period sufficient to entirely remove the small contacts not covered by the bonding pad, and (5) attaching a wire lead to the surface of said bonding pad.
Claim 4
Independent Claim
142 words
The method of making a substantially ohmic low resistance contact to the light emitting surface of a light emitting semiconductor device which is of the III-V compound semiconductor type comprising the steps of (1) forming on said light emitting surface a regular array of small metallic contacts, (2) heating said device to alloy a portion of each said contact to said light emitting surface, (3) selectively depositing a large area metal bonding pad on said light emitting surface and over a plurality of said small contacts, said pad having a thickness at least about an order of magnitude greater than the thickness of small contacts, (4) subjecting the contact surface to sputter etching for a period sufficient to entirely remove the small contacts not covered by the bonding pad, and (5) attaching a wire lead to the surface of said bonding pad.
Claim 5
Dependent Claim
26 words
The method in accordance with claim 2 in which said small metallic contacts are an alloy of gold and beryllium and said bonding pad is gold.
Claim 6
Dependent Claim
28 words
The method in accordance with claim 2 in which the semiconductor material is one selected from the group consisting of gallium arsenide, gallium phosphide, and gallium alluminum phosphide.
Claim 7
Dependent Claim
38 words
The method in accordance with claim 2 in which said small metallic contacts have a diameter of about 1.5 mils and are spaced about 3.25 mils apart, and said bonding pad has a diameter of about 9 mils.
Claim 8
Dependent Claim
20 words
The method in accordance with claim 2 in which said sputter etching comprises a process of bombardment using argon ions.
Claim 9
Dependent Claim
26 words
The process in accordance with claim 2 in which said wire lead is attached to the surface of said bonding pad by thermocompression and/or ultrasonic bonding.
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) | 1983-11-11 | 1984-05-12 | 1984-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-11 | 1988-05-12 | 1988-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-11 | 1992-05-12 | 1992-11-11 | $7700.00 | Window Closed / Lapsed |