US4733292A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of fragile devices
Assignee: The General Electric Company PLC
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Filing: 1986-08-06
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Granted: 1988-03-22
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Expires: 2006-08-06
Abstract
Abstract A method of fabricating a generally planar device such as a lead frame, having fragile portions contiguous respectively with relatively robust portions, which includes in sequence, the steps of providing a robust, generally sheet-like blank, removing material from selective portions of a surface layer of the blank at one of its main surfaces to define first portions of the surface layer to be the relatively robust portions in the finished device and second portions to be fragile portions of the finished device, firmly embedding the second portions in a fixing material layer, and removing material from the other main surface of the blank in the region of the embedded portions to a sufficient depth to expose an underside of the surface layer, thereby to isolate the embedded portions from each other and to render them thinner and thus more fragile than the first portions. With such a method, there is fabricated a generally planar lead frame including several leads, each having a relatively robust portion and a contiguous, relatively fragile portion thinner and more narrow than the robust portion, the fragile portion having a flat face. The lead frame further includes a flat support in the plane of the lead frame, all of the fragile portions being embedded in the flat support such that only the flat face of each fragile portion is exposed in the plane for electrical contact, and each fragile portion is as wide at the flat face as it is beneath that flat face.
Inventors
- 👤 Charles R. Jarvis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:02
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/01; H10W70/04; H10W70/042; H10W70/40; H10W70/421; H10W74/00; H10W90/00; H10W90/701; H10W90/751; H10W90/756; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49121
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
168 words
A method of fabricating a generally planar device having fragile portions contiguous respectively with relatively robust portions, comprising, in sequence, the steps of: (a) providing a robust, generally sheet-like blank having opposite main surfaces; (b) removing material from selected portions of a surface layer of the blank at one of the main surfaces, to define first and second remaining portions of the surface layer, the second portions to be the fragile portions of the finished device and the first portions being contiguous with respective ones of the first portions and to be the relatively robust portions in the finished device; (c) firmly embedding the second portions of the surface layer in a fixing material layer; and (d) removing material from the other main surface of the blank in the region of the embedded portions to a sufficient depth to expose an underside of the surface layer, thereby to isolate the embedded portions from each others and to render them thinner and thus more fragile than the first portions.
Claim 2
Independent Claim
168 words
A method of fabricating a generally planar device having fragile portions contiguous respectively with relatively robust portions, comprising, in sequence, the steps of: (a) providing a robust, generally sheet-like blank having opposite main surfaces; (b) removing material from selected portions of a surface layer of the blank at one of the main surfaces, to define first and second remaining portions of the surface layer, the second portions to be the fragile portions of the finished device and the first portions being contiguous with respective ones of the first portions and to be the relatively robust portions in the finished device; (c) firmly embedding the second portions of the surface layer in a fixing material layer; and (d) removing material from the other main surface of the blank in the region of the embedded portions to a sufficient depth to expose an underside of the surface layer, thereby to isolate the embedded portions from each others and to render them thinner and thus more fragile than the first portions.
Claim 3
Dependent Claim
55 words
A method as in claim 1, wherein the planar device is a lead frame of which each fragile, second portion and its corresponding relatively robust first portion together constitute a lead, and the step of removing material from the surface layer of the blank comprises the step of defining a lead pattern for the device.
Claim 4
Dependent Claim
37 words
A method as in claim 2, wherein the step of providing a blank comprises the step of providing a blank formed from a material selected from the group of materials consisting of nickel-alloys, copper and copper-based alloys.
Claim 5
Dependent Claim
44 words
A method as in claim 2, wherein the steps of removing material include the step of forming each first portion as a leg which is tough enough to withstand handling, and forming each embedded portion as an extremely fine conductor finer than human hair.
Claim 6
Dependent Claim
39 words
A method as in claim 2, wherein the steps of removing material include the step of forming each first portion as a leg which is tough enough to withstand handling, and forming each embedded portion about 25 microns wide.
Claim 7
Dependent Claim
59 words
A method as claimed in claim 2, wherein said step of removing material from the other main surface includes the step of removing material to a depth equal to roughly half the original thickness of the blank, so that the embedded portions, constituting inner portions of the leads, have a thickness roughly half the original thickness of the blank.
Claim 8
Independent Claim
19 words
A method as claimed in 1, wherein said steps of removing material are performed by a chemical etching technique.
Claim 9
Independent Claim
19 words
A method as claimed in 2, wherein said steps of removing material are performed by a chemical etching technique.
Claim 10
Independent Claim
32 words
A method as claimed in 1, in which the first and second portions are defined simultaneously in said step of removing material from selected portions of the surface layer of the blank.
Claim 11
Dependent Claim
57 words
A method as claimed in claim 9, further comprising the step of removing material from the other main surface of the blank in the region of the first portions, so as to isolate the first portions from each other, during said step of removing material from the other main surface in the region of the embedded portions.
Claim 12
Dependent Claim
38 words
A method as claimed in claim 2, wherein said step of firmly embedding includes the step of firmly embedding the second portions in a fixing material seleceted from the group consisting of silica-filled epoxy, glass and glass-ceramic materials.
Claim 13
Dependent Claim
11 words
A lead frame fabricated by the method claimed in claim 13.
Claim 14
Dependent Claim
90 words
A generally planar lead frame comprising: several leads each having a relatively robust portion and a contiguous, relatively fragile portion thinner and narrower than the robust portion, the fragile portion having a flat face; and a flat support in the plane of the lead-frame, all of the fragile portions being embedded in said flat support such only said flat face of each fragile portion is exposed in said plane for electrical contact, and each fragile portion is as wide at said flat face as it is beneath that flat face.
Claim 15
Dependent Claim
90 words
A generally planar lead frame comprising: several leads each having a relatively robust portion and a contiguous, relatively fragile portion thinner and narrower than the robust portion, the fragile portion having a flat face; and a flat support in the plane of the lead-frame, all of the fragile portions being embedded in said flat support such only said flat face of each fragile portion is exposed in said plane for electrical contact, and each fragile portion is as wide at said flat face as it is beneath that flat face.
References Cited (Backward Citations)
US3539259A
Cited
US3532802A
Cited
US3795044A
Cited
US3711625A
Cited
GB2025129A
Cited
US4404059A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-22 | 1991-09-21 | 1992-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-22 | 1995-09-21 | 1996-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-22 | 1999-09-21 | 2000-03-22 | $7700.00 | Window Closed / Lapsed |