US4897164A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing the through hole walls of a printed wiring board for electroplating
Assignee: MacDermid Acumen Inc
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Filing: 1989-04-24
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Granted: 1990-01-30
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Expires: 2009-04-24
Abstract
Abstract In the process for electroplating the walls of through holes in a laminated printed wiring board comprised of at least one non-conducting layer laminated to at least two separate conductive metal layers, which comprises the steps: (a) contacting said printed wiring board having said through holes with a liquid dispersion of carbon blaock comprised of: (1) carbon black particles having an average particle size of less than about 3.0 microns in said dispersion; (2) an effective dispersing amount of a surfactant which is compatible with said carbon black; and (3) a liquid dispersing medium, wherein the amount of carbon black is sufficient to coat substantially all of said non-conducting surfaces and is less than about 4% by weight of said liquid dispersion; (b) separating substantially all of the liquid dispersing medium from said applied dispersion, thereby depositing said carbon black particles in a substantially continuous layer on said non-conducting portions of said hole walls; (c) microetching said metal layers of said printed wiring board to remove deposited carbon black therefrom; (e) electroplating a substantially continuous metal layer over the deposited carbon black layer on said non-conducting portions of hole walls, thereby electrically connecting said metal layers of said printed wiring board; wherein said improvement comprises: contacting said deposited carbon black particles after step (b) and before step (c) with aqueous alkaline solution of an alkali metal borate.
Inventors
- 👤 Anthony M. Piano
- 👤 Randolfo Galvez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:34
CPC Classifications
C; C25; C25D; C25D5/00; C25D5/54; H; H05; H05K; H05K3/00; H05K3/40; H05K3/42; H05K3/423; H05K3/424; H05K2201/00; H05K2201/03; H05K2201/032; H05K2201/0323; H05K2203/00; H05K2203/12; H05K2203/122; H05K3/38; H05K3/382; H05K3/383; H05K3/425; H05K3/427; Y; Y10; Y10S; Y10S205/00; Y10S205/92
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
229 words
In the process for electroplating the walls of through holes in a laminated printed wiring board comprised of at least one non-conducting layer laminated to at least two separate conductive metal layers, which comprises the steps: (a) contacting said printed wiring board having said through holes with a liquid dispersion of carbon black comprised of: (1) carbon black particles having an average particle size of less than about 3.0 microns in said dispersion; (2) an effective dispersing amount of a surfactant which is compatible with said carbon black; and (3) a liquid dispersing medium, wherein the amount of carbon black is sufficient to coat substantially all of said non-conducting surfaces and is less than about 4% by weight of said liquid dispersion; (b) separating substantially all of the liquid dispersing medium from said applied dispersion, thereby depositing said carbon black particles in a substantially continuous layer on said non-conducting portions of said hole walls; (c) microetching said metal layers of said printed wiring board to remove deposited carbon black therefrom; and (d) later electroplating a substantially continuous metal layer over the deposited carbon black layer on said non-conducting portions of hole walls, thereby electrically connecting said metal layers of said printed wiring board; wherein said improvement comprises: contacting said deposited carbon black particles after step (b) and before step (c) with aqueous alkaline solution of an alkal metal borate.
Claim 2
Dependent Claim
229 words
In the process for electroplating the walls of through holes in a laminated printed wiring board comprised of at least one non-conducting layer laminated to at least two separate conductive metal layers, which comprises the steps: (a) contacting said printed wiring board having said through holes with a liquid dispersion of carbon black comprised of: (1) carbon black particles having an average particle size of less than about 3.0 microns in said dispersion; (2) an effective dispersing amount of a surfactant which is compatible with said carbon black; and (3) a liquid dispersing medium, wherein the amount of carbon black is sufficient to coat substantially all of said non-conducting surfaces and is less than about 4% by weight of said liquid dispersion; (b) separating substantially all of the liquid dispersing medium from said applied dispersion, thereby depositing said carbon black particles in a substantially continuous layer on said non-conducting portions of said hole walls; (c) microetching said metal layers of said printed wiring board to remove deposited carbon black therefrom; and (d) later electroplating a substantially continuous metal layer over the deposited carbon black layer on said non-conducting portions of hole walls, thereby electrically connecting said metal layers of said printed wiring board; wherein said improvement comprises: contacting said deposited carbon black particles after step (b) and before step (c) with aqueous alkaline solution of an alkal metal borate.
Claim 3
Dependent Claim
23 words
The process of claim 1 wherein said aqueous alkaline solution is a mixture of an alkaline metal hydroxide and an alkali metal borate.
Claim 4
Dependent Claim
12 words
The process of claim 1 wherein said alkaline borate is sodium borate.
Claim 5
Dependent Claim
31 words
The process of claim 1 wherein said contacting step of the improvement is carried out by immersing the printed wiring board in an aqueous alkaline bath containing said alkali metal borate.
Claim 6
Dependent Claim
24 words
The process of claim 1 wherein said contacting step of the improvement occurs at a temperature from about 30° C. to about 60° C.
Claim 7
Dependent Claim
70 words
The process of claim 1 wherein said contacting step of the improvement is carried out by placing said printed wire board in an aqueous alkaline bath containing said alkali metal borate at a temperature from about 30° C. to about 60° C. and said solution comprising water and about 2 to about 50 grams of sodium borate per liter of water having a pH from about 9.5 to about 11.5.
Claim 8
Dependent Claim
38 words
The process of claim 6 wherein said liquid carbon black dispersion further comprises a sufficient amount of at least one alkaline hydroxide to raise the pH of said liquid dispersion in the range from about 10 to 12.
Claim 9
Dependent Claim
12 words
The process of claim 7 wherein said alkaline hydroxide is potassium hydroxide.
Claim 10
Dependent Claim
18 words
The process of claim 8 wherein said liquid dispersion contains less than about 10% by weight solids constituents.
Claim 11
Dependent Claim
20 words
The process of claim 7 wherein said carbon black particles have an initial pH from about 2 to about 4.
Claim 12
Dependent Claim
21 words
The process of claim 7 wherein said printed wiring board is contacted with a cleaner and a conditioner before step (a).
Claim 13
Dependent Claim
14 words
The process of claim 7 wherein said surfactant is a phosphate ester anionic surfactant.
Claim 14
Dependent Claim
11 words
The process of claim 7 wherein said conductive metal is copper.
Claim 15
Dependent Claim
12 words
The process of claim 7 wherein said liquid dispersing medium is water.
Claim 16
Dependent Claim
17 words
The process of claim 7 wherein said microetch in step (c) comprises sodium persulfate and sulfuric acid.
References Cited (Backward Citations)
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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) | 1993-01-29 | 1993-07-31 | 1994-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-29 | 1997-07-31 | 1998-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-29 | 2001-07-31 | 2002-01-30 | $7700.00 | Window Closed / Lapsed |