US3921285A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for joining microminiature components to a carrying structure
Assignee: International Business Machines Corp
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Filing: 1974-07-15
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Granted: 1975-11-25
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Expires: 1994-07-15
Abstract
Abstract A method for joining microminiature components to a carrying structure wherein the height of the electrical connecting structures are adjusted during the joining process. The height of the electrical connecting structures may either be adjusted during the original joining of the component to the carrying structure or it may be done in a two step solder reflow process. In the two step process the component is first joined to the carrying structure and then an additional height is given to the electrical connecting structures which improves the lifetime of the joining terminals. In each of the alternatives, a bridge together with a vaporizable fluid which wets both the bridge and a surface of the component opposite to the surface which carries the connecting structure. At the temperature of melting of the material used in the connecting structure, the fluid evaporates and surface tension pulls the component closer to the bridge which in turn elongates or increases the height of the electrical connecting structures between the carrying structure and the component.
Inventors
- 👤 Bogdan Krall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:17
CPC Classifications
H; H10; H10W; H10W95/00; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/341; H05K3/3431; H05K3/3436; H05K2201/00; H05K2201/20; H05K2201/2036; H05K2203/00; H05K2203/04; H05K2203/0465; H05K2203/07; H05K2203/0756; H05K2203/0776; H05K2203/08; H05K2203/083; H05K2203/30; H05K2203/306; H10W72/00; H10W72/071; H10W72/072; H10W72/07231; H10W72/07236; H10W72/20; H10W72/251; H10W72/252; H10W72/851; H10W72/874; H10W72/877; Y; Y02; Y02P; Y02P70/00; Y02P70/50; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/4913; Y10T29/49144
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
150 words
A method for elongating the solder terminals physically and electrically connecting a component to a carrying structure comprising: positioning a component onto a carrying structure spaced therefrom by solder terminals; placing an amount of vaporizable material upon the surface of said component opposite to the surface having said solder terminals; placing a bridge over the components so that there is a cavity between the surface of said component having said material thereon and the bottom of the bridge; said material becomes liquid with temperature rise at least before the said solder melts at which time it wets the said bridge and said surface; heating the structure until said solder terminals are softened and until a desired portion of said material is evaporated which pulls by surface tension the said component closer to said bridge and which in turn elongates the said solder terminals; and cooling the structure to room temperature.
Claim 2
Independent Claim
150 words
A method for elongating the solder terminals physically and electrically connecting a component to a carrying structure comprising: positioning a component onto a carrying structure spaced therefrom by solder terminals; placing an amount of vaporizable material upon the surface of said component opposite to the surface having said solder terminals; placing a bridge over the components so that there is a cavity between the surface of said component having said material thereon and the bottom of the bridge; said material becomes liquid with temperature rise at least before the said solder melts at which time it wets the said bridge and said surface; heating the structure until said solder terminals are softened and until a desired portion of said material is evaporated which pulls by surface tension the said component closer to said bridge and which in turn elongates the said solder terminals; and cooling the structure to room temperature.
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein the said component is physically and electrically connected to said carrying structure at the beginning of the method for elongating the said solder terminals.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein the said component is physically and electrically connected to said carrying structure while simultaneously forming the desired elOngated said solder terminals.
Claim 5
Dependent Claim
16 words
The method of claim 1 wherein the said solder terminals are composed of a lead-indium solder.
Claim 6
Dependent Claim
16 words
The method of claim 1 wherein the said solder terminals are composed of a tin-lead solder.
Claim 7
Dependent Claim
15 words
The method of claim 1 wherein the vaporizable material is a liquid at room temperature.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein the solder terminals are elongated at least 50%.
Claim 9
Dependent Claim
20 words
The method of claim 1 wherein the component is a silicon semiconductor chip and the carrying structure a ceramic substrate.
Claim 10
Dependent Claim
16 words
The method of claim 8 wherein the substrate is composed of alumina with metallic conductors thereon.
Claim 11
Dependent Claim
15 words
The method of claim 9 wherein the metallic conductors are composed of chromium and copper.
Claim 12
Dependent Claim
19 words
The method of claim 9 wherein the metallic conductors are composed of a noble metal containing coalesced glass frit.
Claim 13
Independent Claim
254 words
A method for positioning microminiature components in electrical contact with and otherwise spaced from a carrying structure while adjusting the height of the electrical connecting structures comprising: providing an electrically conductive pattern on said carrying structure having a plurality of connecting areas; said connecting areas being wettable with solder; the areas immediately surrounding the said connecting areas being not wettable by solder; applying a coating of solder to the said connecting areas; positioning a microminiature component having solder contacts extending therefrom onto preselected connecting areas of said conductive pattern; placing an amount of vaporizable material upon the surface of the said component opposite to the surface having the solder contacts; placing a bridge over the component so that there is a cavity between the surface of said component having said material thereon and the bottom of the bridge; heating the said solder contacts and said preselected connecting areas to a temperature and for time sufficient to soften the respective solder areas and to fuse the said component to the said substrate in spaced relation to said substrate, the surface tension of said solder during heating being sufficient to support said microminiature component from the surface of said substrate until said contacts are fused to said connecting areas and the said material which becomes liquid at least before the said solder melts wets both the surface and the bridge, the said material evaporating which pull by surface tension the said component closer to said bridge and which in turn elongates the said electrical conducting structures.
Claim 14
Independent Claim
254 words
A method for positioning microminiature components in electrical contact with and otherwise spaced from a carrying structure while adjusting the height of the electrical connecting structures comprising: providing an electrically conductive pattern on said carrying structure having a plurality of connecting areas; said connecting areas being wettable with solder; the areas immediately surrounding the said connecting areas being not wettable by solder; applying a coating of solder to the said connecting areas; positioning a microminiature component having solder contacts extending therefrom onto preselected connecting areas of said conductive pattern; placing an amount of vaporizable material upon the surface of the said component opposite to the surface having the solder contacts; placing a bridge over the component so that there is a cavity between the surface of said component having said material thereon and the bottom of the bridge; heating the said solder contacts and said preselected connecting areas to a temperature and for time sufficient to soften the respective solder areas and to fuse the said component to the said substrate in spaced relation to said substrate, the surface tension of said solder during heating being sufficient to support said microminiature component from the surface of said substrate until said contacts are fused to said connecting areas and the said material which becomes liquid at least before the said solder melts wets both the surface and the bridge, the said material evaporating which pull by surface tension the said component closer to said bridge and which in turn elongates the said electrical conducting structures.
Claim 15
Dependent Claim
15 words
The method of claim 12 wherein said solder terminals are composed of a lead-indium solder.
Claim 16
Dependent Claim
15 words
The method of claim 12 wherein said solder terminals are composed of a tin-lead solder.
Claim 17
Dependent Claim
25 words
The method of claim 12 wherein said component is a silicon semiconductor chip and said carrying structure is an alumina substrate with metallic conductors thereon.
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) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |