Patent US4086375A successfully refreshed from Google Patents.
US4086375A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Batch process providing beam leads for microelectronic devices having metallized contact pads
Assignee: Boeing North American Inc
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Filing: 1975-11-07
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Granted: 1978-04-25
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Expires: 1995-11-07
Abstract
Abstract A monometallic batch process for forming beam leads of a preferred metal such as aluminum or gold. The process is applied to a wafer of finished microelectronic devices already having metal contact pads of the same preferred metal. Where aluminum is the desired metal, high deposition rates are used to minimize aluminum oxide contamination. High yield is achieved by forming the beam leads to have an elevated cantilevered configuration, by deep scribing of the wafer and, when desired, by providing an energy absorbing cushion to reduce the effect of collisions between chip edges and beam leads.
Inventors
- 👤 Theodore J. LaChapelle, Jr.
- 👤 John R. Davis
- 👤 James J. Licari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:27
CPC Classifications
H; H10; H10P; H10P76/00; H10P76/40
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
137 words
A method of forming beam leads for a plurality of electronic devices fabricated on a wafer, the electronic devices having contact pads of a metal, said method comprising: depositing a relatively thin layer of a removable release material on said wafer wherein said removable release material is susceptible to etching by etchants which do not react significantly with said metal; selectively masking and etching said relatively thin layer of a removable release material to remove said release material from said contact pads; depositing a relatively thick layer of said metal on said relatively thin layer of a removable release material and on said contact pads; selectively masking and etching said relatively thick layer of said metal to form interdigitated beam leads for said electronic devices; and removing the remainder of said removable release material from said wafer.
Claim 2
Independent Claim
137 words
A method of forming beam leads for a plurality of electronic devices fabricated on a wafer, the electronic devices having contact pads of a metal, said method comprising: depositing a relatively thin layer of a removable release material on said wafer wherein said removable release material is susceptible to etching by etchants which do not react significantly with said metal; selectively masking and etching said relatively thin layer of a removable release material to remove said release material from said contact pads; depositing a relatively thick layer of said metal on said relatively thin layer of a removable release material and on said contact pads; selectively masking and etching said relatively thick layer of said metal to form interdigitated beam leads for said electronic devices; and removing the remainder of said removable release material from said wafer.
Claim 3
Dependent Claim
12 words
The method set forth in claim 1 wherein said metal is aluminum.
Claim 4
Dependent Claim
12 words
The method set forth in claim 1 wherein said metal is gold.
Claim 5
Dependent Claim
24 words
The method set forth in claim 1 wherein said removable release material is selected from the group consisting of copper, magnesium, zinc and titanium.
Claim 6
Dependent Claim
47 words
The method set forth in claim 2 wherein the step of depositing said relatively thick layer of aluminum is accomplished by evaporating said aluminum in a vacuum chamber in a manner which produces a relatively high rate of deposition of said aluminum essentially free of aluminum oxide.
Claim 7
Dependent Claim
83 words
The method set forth in claim 1 wherein said wafer has first and second opposing sides, wherein said electronic devices are fabricated on said first side of said wafer and wherein said electronic devices have boundaries spaced apart from each other leaving street regions free of usable circuitry between said boundaries, said method comprising scribing said wafer on the second side thereof to a depth of about ninety percent to ninety-five percent of the thickness of said wafer in the street regions thereof.
Claim 8
Dependent Claim
98 words
The method set forth in claim 1 wherein said electronic devices have boundaries spaced apart from each other leaving street regions free of usable circuitry between said boundaries and wherein, prior to the step of depositing said relatively thin layer of a removable release material, said method comprises: depositing a relatively thin layer of a flexible organic material on said wafer; selectively masking and etching said layer of flexible organic material to form a pattern thereof on the street regions of said wafer; and curing said flexible organic material to form an energy absorbing cushion resistant to etchants.
Claim 9
Dependent Claim
24 words
The method set forth in claim 7 wherein said flexible organic material is selected from the group consisting of polymerizable resins, elastomers and fluorocarbons.
Claim 10
Dependent Claim
14 words
The method set forth in claim 8 wherein said flexible organic material is polyimide.
Claim 11
Dependent Claim
74 words
The method set forth in claim 1 wherein, prior to the step of depositing said relatively thin layer of a removable release material, said method comprises: depositing a relatively thin layer of a flexible organic material on said wafer; selectively masking and etching said layer of flexible organic material to remove said flexible organic material from above said contact pads; and curing said flexible organic material to cause it to be resistant to etchants.
Claim 12
Dependent Claim
24 words
The method set forth in claim 10 wherein said flexible organic material is selected from the group consisting of polymerizable resins, elastomers and fluorocarbons.
Claim 13
Dependent Claim
14 words
The method set forth in claim 11 wherein said flexible organic material is polyimide.
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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) | 1981-04-24 | 1981-10-24 | 1982-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-24 | 1985-10-24 | 1986-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-24 | 1989-10-24 | 1990-04-25 | $7700.00 | Window Closed / Lapsed |