US3708876A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vacuum-heat treatment of printed circuit boards
Assignee: Unisys Corp
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Filing: 1969-01-28
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Granted: 1973-01-09
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Expires: 1989-01-28
Abstract
Abstract Relates to the avoidance of electrical discontinuities arising in the production of two-sided printed circuit boards having plated-through-holes and particularly occurring in the use of solder for improving the electrical interconnections. Research disclosed that the cause of these discontinuities lay in the material of the boards surrounding the holes which either included entrapped gas or matter vaporizable under the high temperatures of the liquid solder applied to fill the holes to assure reliable plated-through-hole connections. A vacuum evaporation operation was incorporated in the fabrication process and found highly useful and efficient in the production of reliable hole connections substantially reducing if not completely eliminating any need to apply solder touch-ups to the boards thereafter. Specifically, the boards were treated prior to the soldering of the plated-through holes to a temperature of approximately 250* F while concurrently being exposed to a vacuum of approximately 10 2 mm Hg for a sufficient time to drive out of the boards all matter vaporizable under such conditions.
Inventors
- 👤 W Klehm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:25
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/0011; H05K3/0055; H05K2201/00; H05K2201/09; H05K2201/09209; H05K2201/095; H05K2201/09572; H05K2203/00; H05K2203/08; H05K2203/083; H05K2203/085; H05K2203/11; H05K2203/1105; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/49155
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
101 words
In the method of making printed circuit boards wherein such boards are composed of a plastic composition and bear electrical conductors on opposite surfaces thereof connected by one or more holes extending through the boards and wherein molten solder is introduced into the holes formed therein, the step of subjecting the boards to a vacuum evaporation treatment prior to the introduction of solder into the holes which includes subjecting the boards to a temperature approaching but below that which would detrimentally affect the material of the boards and while concurrently subjecting the boards to a vacuum of at least 1 Torr.
Claim 2
Dependent Claim
101 words
In the method of making printed circuit boards wherein such boards are composed of a plastic composition and bear electrical conductors on opposite surfaces thereof connected by one or more holes extending through the boards and wherein molten solder is introduced into the holes formed therein, the step of subjecting the boards to a vacuum evaporation treatment prior to the introduction of solder into the holes which includes subjecting the boards to a temperature approaching but below that which would detrimentally affect the material of the boards and while concurrently subjecting the boards to a vacuum of at least 1 Torr.
Claim 3
Dependent Claim
91 words
In the method of making printed circuit boards composed at least in part of plastic material and bearing printed wiring on opposite surfaces thereof connected by one or more holes lined with electrically conductive material, the step of subjecting such boards prior to the application of molten solder thereto to a vacuum evaporation treatment operating at a temperature of approximately 250* F and at a vacuum of approximately 10 2 mm Hg for the duration of time sufficient to drive out substantially all material in the boards vaporizable under such conditions.
Claim 4
Dependent Claim
91 words
In the method of making printed circuit boards composed at least in part of plastic material and bearing printed wiring on opposite surfaces thereof connected by one or more holes lined with electrically conductive material, the step of subjecting such boards prior to the application of molten solder thereto to a vacuum evaporation treatment operating at a temperature of approximately 250* F and at a vacuum of approximately 10 2 mm Hg for the duration of time sufficient to drive out substantially all material in the boards vaporizable under such conditions.
Claim 5
Dependent Claim
105 words
In the method of manufacturing printed circuit boards wherein such boards are composed of a plastic composition and bear conductors on surfaces thereof connected by plated-through-holes, the method of pretreating each such hole plated board prior to the application of solder to fill the holes comprising the steps of placing the board in an air-tight chamber, heating the chamber to a temperature above 212* F but below that at which the material of the board would be detrimentally affected thereby and concurrently lowering the vacuum in the chamber below 1 Torr for a time sufficient to drive out substantially all vaporizable matter in the board.
Claim 6
Dependent Claim
105 words
In the method of manufacturing printed circuit boards wherein such boards are composed of a plastic composition and bear conductors on surfaces thereof connected by plated-through-holes, the method of pretreating each such hole plated board prior to the application of solder to fill the holes comprising the steps of placing the board in an air-tight chamber, heating the chamber to a temperature above 212* F but below that at which the material of the board would be detrimentally affected thereby and concurrently lowering the vacuum in the chamber below 1 Torr for a time sufficient to drive out substantially all vaporizable matter in the board.
Claim 7
Independent Claim
90 words
The method of preparing plastic composition boards having printed conductors on surfaces thereof connected by plated-through-holes for the application of liquid solder for filling the holes which comprises subjecting each board to a concurrent heat and vacuum treatment to outgas the board, the temperature of the treatment being above 212* F but below the temperature which would detrimentally affect the composition of the board and the vacuum being less than 1 Torr, and then thereafter without further treatment of the boards filling the plated-through-holes of the board with liquid solder.
Claim 8
Independent Claim
90 words
The method of preparing plastic composition boards having printed conductors on surfaces thereof connected by plated-through-holes for the application of liquid solder for filling the holes which comprises subjecting each board to a concurrent heat and vacuum treatment to outgas the board, the temperature of the treatment being above 212* F but below the temperature which would detrimentally affect the composition of the board and the vacuum being less than 1 Torr, and then thereafter without further treatment of the boards filling the plated-through-holes of the board with liquid solder.
Claim 9
Dependent Claim
27 words
The invention described in claim 4 characterized in that the temperature of the treatment is approximately 250* F and the vacuum is approximately 10 2 mm Hg.
Claim 10
Dependent Claim
97 words
In the method of manufacturing printed circuit boards wherein such boards are composed of a plastic composition and bear conductors on surfaces thereof connected by plated-through-holes, the method of pretreating such boards prior to the application of solder to fill the holes including the steps of subjecting such boards to a vacuum evaporation treatment of several hours duration at a temperature above 212* F but below that at which the material of the board would be detrimentally affected thereby and concurrently at a vacuum at least 1 Torr, and then thereafter filling the plaTed-through-holes with liquid solder.
Claim 11
Dependent Claim
97 words
In the method of manufacturing printed circuit boards wherein such boards are composed of a plastic composition and bear conductors on surfaces thereof connected by plated-through-holes, the method of pretreating such boards prior to the application of solder to fill the holes including the steps of subjecting such boards to a vacuum evaporation treatment of several hours duration at a temperature above 212* F but below that at which the material of the board would be detrimentally affected thereby and concurrently at a vacuum at least 1 Torr, and then thereafter filling the plaTed-through-holes with liquid solder.
Claim 12
Independent Claim
95 words
The method of outgassing plastic composition boards having printed conductors on the exterior surfaces thereof and containing plated-through-hole interconnections which comprises the steps of loading a vacuum chamber with a batch of such printed conductor boards of like composition, heating the chamber to a temperature above 212* F but below the temperature which would detrimentally affect the boards therein, lowering the vacuum in the chamber below 1 Torr while the boards are so heated in the chamber, and maintaining such temperature and vacuum conditions of the chamber for at least approximately 3 to 5 hours.
Claim 13
Independent Claim
95 words
The method of outgassing plastic composition boards having printed conductors on the exterior surfaces thereof and containing plated-through-hole interconnections which comprises the steps of loading a vacuum chamber with a batch of such printed conductor boards of like composition, heating the chamber to a temperature above 212* F but below the temperature which would detrimentally affect the boards therein, lowering the vacuum in the chamber below 1 Torr while the boards are so heated in the chamber, and maintaining such temperature and vacuum conditions of the chamber for at least approximately 3 to 5 hours.
Claim 14
Dependent Claim
97 words
In the method of fabricating plastic composition boards which bear printed wiring on opposite surfaces thereof and are electrically connected by plated-through-holes and which are subjected to a soldering operation filling the holes with molten solder, the steps of preparing such boards for the soldering operation which comprises enclosing the boards within an airtight chamber, heating the chamber to a temperature higher than 212* F but no higher than that which would detrimentally affect the boards, and while the boards are so being heated maintaining the chamber in a high vacuum condition of less than 1 Torr.
Claim 15
Dependent Claim
97 words
In the method of fabricating plastic composition boards which bear printed wiring on opposite surfaces thereof and are electrically connected by plated-through-holes and which are subjected to a soldering operation filling the holes with molten solder, the steps of preparing such boards for the soldering operation which comprises enclosing the boards within an airtight chamber, heating the chamber to a temperature higher than 212* F but no higher than that which would detrimentally affect the boards, and while the boards are so being heated maintaining the chamber in a high vacuum condition of less than 1 Torr.
Claim 16
Dependent Claim
61 words
The invention described in claim 8 characterized in that the temperature to which the chamber is heated is approximately 250* F and that the vacuum therein is approximately 10 2 mm Hg, and further characterized in that such temperature and vacuum levels in the chamber are maintained until substantially all material in the boards vaporizable under such conditions are outgassed therefrom.
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) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |