US4398993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Neutralizing chloride ions in via holes in multilayer printed circuit boards
Assignee: International Business Machines Corp
•
Filing: 1982-06-28
•
Granted: 1983-08-16
•
Expires: 2002-06-28
Abstract
Abstract A neutralization process is provided for neutralizing chloride ions in etched via holes in multilayer printed circuit boards. The process comprises two dip operations of the board in a Neutra-Clean and water solution which is continuously re-circulated. This is followed by subjecting the board to a heated de-ionized cascaded water feed, an ambient overflow de-ionized water rinse, and conveyorized air drying. The Neutra-Clean solution has the ability to penetrate down to the bottom of the via hole and to attract the free chloride ions from the etchant residue. The de-ionized water feed and rinse steps rinse out and remove the Neutra-Clean solution and any residuals formed by chemical reaction.
Inventors
- 👤 David W. Hume, Jr.
- 👤 John Rasile
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:54
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/22; H05K3/26; H05K3/0011; H05K3/0017; H05K3/0026; H05K3/0032; H05K3/0035; H05K3/02; H05K3/022; H05K3/025; H05K2201/00; H05K2201/03; H05K2201/0332; H05K2201/0335; H05K2201/0355; H05K2201/09; H05K2201/09209; H05K2201/095; H05K2201/09509; H05K2203/00; H05K2203/01; H05K2203/0147; H05K2203/0152; H05K2203/05; H05K2203/0548; H05K2203/0554; H05K2203/07; H05K2203/0703; H05K2203/0723; H05K2203/0726; H05K2203/0756; H05K2203/0766; H05K2203/0779; H05K2203/0786; H05K2203/13; H05K2203/1377; H05K2203/1388
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
65 words
The process of drilling blind via holes in a printed circuit board composite which consists of a peel-apart-copper layer covering an epoxy substrate which consists of the steps of: etching holes through the peel-apart-copper layer; subjecting said holes to a circulating Neutra-Clean solution; cleaning said holes to remove said Neutra-Clean solution; and utilizing a laser drill to extend said etched holes into the epoxy substrate.
Claim 2
Dependent Claim
65 words
The process of drilling blind via holes in a printed circuit board composite which consists of a peel-apart-copper layer covering an epoxy substrate which consists of the steps of: etching holes through the peel-apart-copper layer; subjecting said holes to a circulating Neutra-Clean solution; cleaning said holes to remove said Neutra-Clean solution; and utilizing a laser drill to extend said etched holes into the epoxy substrate.
Claim 3
Dependent Claim
97 words
The process of drilling blind via holes in a printed circuit board composite which consists of a peel-apart-copper layer covering an epoxy substrate which consists of the steps of: etching holes through the peel-apart-copper layer with a cupric chloride etchant containing HCl acid; subjecting said holes to a circulating solution of Neutra-Clean and water to neutralize chloride ions in the etchant residue in said holes; cleaning said holes with de-ionized water to remove said Neutra-Clean solution and any residuals due to chemical reaction; and utilizing a laser drill to extend said etched holes into the epoxy substrate.
Claim 4
Dependent Claim
97 words
The process of drilling blind via holes in a printed circuit board composite which consists of a peel-apart-copper layer covering an epoxy substrate which consists of the steps of: etching holes through the peel-apart-copper layer with a cupric chloride etchant containing HCl acid; subjecting said holes to a circulating solution of Neutra-Clean and water to neutralize chloride ions in the etchant residue in said holes; cleaning said holes with de-ionized water to remove said Neutra-Clean solution and any residuals due to chemical reaction; and utilizing a laser drill to extend said etched holes into the epoxy substrate.
Claim 5
Dependent Claim
105 words
The process of drilling blind via holes in a printed circuit board composite which consists of a peel-apart-copper layer covering an epoxy substrate which consists of the steps of: etching holes through the peel-apart-copper layer with a cupric chloride etchant containing HCl acid; first and second 5 minute dip operations of said holes in a solution of 50% Neutra-Clean and 50% water at 120° F.; subjecting said holes to a 2 minute heated de-ionized cascaded water feed at 100° F. subjecting said holes to a 2 minute ambient overflow de-ionized water rinse; and utilizing a laser drill to extend said etched holes into the epoxy.
Claim 6
Dependent Claim
105 words
The process of drilling blind via holes in a printed circuit board composite which consists of a peel-apart-copper layer covering an epoxy substrate which consists of the steps of: etching holes through the peel-apart-copper layer with a cupric chloride etchant containing HCl acid; first and second 5 minute dip operations of said holes in a solution of 50% Neutra-Clean and 50% water at 120° F.; subjecting said holes to a 2 minute heated de-ionized cascaded water feed at 100° F. subjecting said holes to a 2 minute ambient overflow de-ionized water rinse; and utilizing a laser drill to extend said etched holes into the epoxy.
Claim 7
Dependent Claim
82 words
A process for neutralizing chloride ions in etched via holes in a multilayer printed circuit board, wherein said via holes are etched by a cupric chloride etchant containing HCl acid, said process comprising the steps of: first and second dip operations of said via holes in a solution of Neutra-Clean and water which is continuously re-circulated; subjecting said via holes to a heated de-ionized cascaded water feed; subjecting said via holes to ambient overflow de-ionized water rinse; and air drying the board.
Claim 8
Dependent Claim
82 words
A process for neutralizing chloride ions in etched via holes in a multilayer printed circuit board, wherein said via holes are etched by a cupric chloride etchant containing HCl acid, said process comprising the steps of: first and second dip operations of said via holes in a solution of Neutra-Clean and water which is continuously re-circulated; subjecting said via holes to a heated de-ionized cascaded water feed; subjecting said via holes to ambient overflow de-ionized water rinse; and air drying the board.
Claim 9
Dependent Claim
124 words
A process for neutralizing chloride ions in etched via holes in a multilayer printed circuit board, wherein said via holes are etched by a cupric chloride etchant containing HCl acid, said process comprising the steps of: first and second dip operations of said via holes in a solution of Neutra-Clean and water which is continuously re-circulated, said solution containing ammonium chloride and sodium chloride which attract free chloride ions from etchant residue in said via holes; subjecting said via holes to a heated de-ionized cascaded water feed; subjecting said via holes to an ambient overflow de-ionized water rinse, said water feed and water rinse removing the Neutra-Clean solution and any residuals due to chemical reaction from said via holes; and air drying the board.
Claim 10
Dependent Claim
124 words
A process for neutralizing chloride ions in etched via holes in a multilayer printed circuit board, wherein said via holes are etched by a cupric chloride etchant containing HCl acid, said process comprising the steps of: first and second dip operations of said via holes in a solution of Neutra-Clean and water which is continuously re-circulated, said solution containing ammonium chloride and sodium chloride which attract free chloride ions from etchant residue in said via holes; subjecting said via holes to a heated de-ionized cascaded water feed; subjecting said via holes to an ambient overflow de-ionized water rinse, said water feed and water rinse removing the Neutra-Clean solution and any residuals due to chemical reaction from said via holes; and air drying the board.
Claim 11
Dependent Claim
99 words
A process for neutralizing chloride ions in etched via holes in a multilayer printed circuit board, wherein said via holes are etched by a cupric chloride etchant containing HCl acid, said process comprising the steps of: first and second 5 minute dip operations of said via holes in a solution of 50% Neutra-Clean and 50% water which is continuously re-circulated at 120° F.; subjecting said via holes to a 2 minute heated de-ionized cascaded water feed at 100° F.; subjecting said via holes to a 2 minute ambient overflow de-ionized water rinse; and conveyorized air drying of the board.
Claim 12
Dependent Claim
99 words
A process for neutralizing chloride ions in etched via holes in a multilayer printed circuit board, wherein said via holes are etched by a cupric chloride etchant containing HCl acid, said process comprising the steps of: first and second 5 minute dip operations of said via holes in a solution of 50% Neutra-Clean and 50% water which is continuously re-circulated at 120° F.; subjecting said via holes to a 2 minute heated de-ionized cascaded water feed at 100° F.; subjecting said via holes to a 2 minute ambient overflow de-ionized water rinse; and conveyorized air drying of the board.
References Cited (Backward Citations)
US4155775A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |