Patent US4175011A successfully refreshed from Google Patents.
US4175011A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sulfate-free method of etching copper pattern on printed circuit boards
Assignee: Honeywell International Inc
•
Filing: 1978-07-17
•
Granted: 1979-11-20
•
Expires: 1998-07-17
Abstract
Abstract In printed circuit board manufacture, a copper pattern on the board is slightly etched and then a tin/lead layer is plated onto the etched copper pattern. The etching step is free of sulfate materials and includes etching the copper pattern with an aqueous solution of hydrogen peroxide and fluoboric acid.
Inventors
- 👤 Nicholas J. Spiliotis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:21
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16; C23F1/18; H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/067
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
80 words
In a method of forming printed circuit boards of a type wherein a copper pattern on a board is etched and then a tin/lead layer is plated onto the etched copper pattern, the improvement wherein the etching step consists essentially of contacting the surface with an aqueous etchant solution comprising between about 0.5 and about 70 weight % hydrogen peroxide, between about 2.5 and about 90 weight % fluoboric acid and between about 5 and about 85 weight % water.
Claim 2
Dependent Claim
80 words
In a method of forming printed circuit boards of a type wherein a copper pattern on a board is etched and then a tin/lead layer is plated onto the etched copper pattern, the improvement wherein the etching step consists essentially of contacting the surface with an aqueous etchant solution comprising between about 0.5 and about 70 weight % hydrogen peroxide, between about 2.5 and about 90 weight % fluoboric acid and between about 5 and about 85 weight % water.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein the aqueous etchant solution comprises between about 2 and about 15 weight % hydrogen peroxide and between about 20 and about 50 weight % fluoboric acid.
Claim 4
Dependent Claim
32 words
The method of claim 2 wherein the aqueous etchant soluton comprises between about 3 and about 7 weight % hydrogen peroxide and between about 35 and about 45 weight % fluoboric acid.
Claim 5
Dependent Claim
34 words
The method of claim 1 wherein said process consists of said etching step, a water rinse, a dip in an aqueous fluoboric acid solution and a step of plating in a tin/lead fluoborate bath.
Claim 6
Dependent Claim
21 words
A method as in claim 1 which comprises said etching step, a water rinse and plating in a tin/lead fluoborate bath.
References Cited (Backward Citations)
US3181984A
Cited
US3293093A
Cited
US3554878A
Cited
US3677949A
Cited
US3864271A
Cited
US3859182A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-11-19 | 1983-05-21 | 1983-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-19 | 1987-05-21 | 1987-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-19 | 1991-05-21 | 1991-11-20 | $7700.00 | Window Closed / Lapsed |