US5576052A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of metallizing high aspect ratio apertures
Assignee: Motorola Solutions Inc
•
Filing: 1996-04-22
•
Granted: 1996-11-19
•
Expires: 2016-04-22
Abstract
Abstract A method of manufacturing high aspect ratio plated through holes in a circuit carrying substrate. High aspect ratio apertures or holes (16) are formed in a substrate (10). A thin film of copper (20) is sputtered onto the substrate and in the apertures that a macroscopically discontinuous copper film (26) is formed on part of the aperture walls. The macroscopically discontinuous copper film is substantially thinner than the copper film that is deposited on the surface. A catalytic copper coating (30) is plated directly on the vacuum deposited thin film of copper by electroless copper plating in a manner sufficient to form a macroscopically continuous copper layer on the aperture walls.
Inventors
- 👤 John K. Arledge
- 👤 Thomas J. Swirbel
- 👤 Joaquin Barreto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:55
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/40; H05K3/4038; H05K3/4076; C; C23; C23C; C23C18/00; C23C18/16; C23C18/1601; C23C18/1633; C23C18/1646; C23C18/165; C23C18/31; C23C18/38; C23C18/40; C23C18/405; C23C28/00; C23C28/02; C23C28/023; H05K3/42; H05K3/422; C23C18/1603; C23C18/1653; C23C18/1689; H05K3/425; H05K3/427
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
127 words
A method of manufacturing a circuit carrying substrate, comprising the following steps in the order named: a) providing a substrate having an aperture therein, the aperture having walls and a high aspect ratio; b) vacuum depositing a thin film of copper on a major surface of the substrate and in the aperture, in a manner sufficient to form a macroscopically discontinuous copper film on the aperture walls, said macroscopically discontinuous copper film being substantially thinner than the thin film of copper deposited on the major surface; and c) depositing a catalytic copper coating directly on the vacuum deposited thin film of copper by immersing the substrate in an electroless copper plating bath in a manner sufficient to form a macroscopically continuous copper layer on the aperture walls.
Claim 2
Independent Claim
127 words
A method of manufacturing a circuit carrying substrate, comprising the following steps in the order named: a) providing a substrate having an aperture therein, the aperture having walls and a high aspect ratio; b) vacuum depositing a thin film of copper on a major surface of the substrate and in the aperture, in a manner sufficient to form a macroscopically discontinuous copper film on the aperture walls, said macroscopically discontinuous copper film being substantially thinner than the thin film of copper deposited on the major surface; and c) depositing a catalytic copper coating directly on the vacuum deposited thin film of copper by immersing the substrate in an electroless copper plating bath in a manner sufficient to form a macroscopically continuous copper layer on the aperture walls.
Claim 3
Dependent Claim
17 words
The method as described in claim 1, wherein the step of vacuum depositing comprises sputtering or evaporation.
Claim 4
Dependent Claim
22 words
The method as described in claim 1, wherein the electroless copper plating bath comprises an alkaline solution of copper, formaldehyde and EDTA.
Claim 5
Dependent Claim
27 words
The method as described in claim 1, wherein the electroless copper plating bath contains trace quantities of palladium, tin or reaction byproducts of palladium, tin or copper.
Claim 6
Dependent Claim
24 words
The method as described in claim 1, wherein the high aspect ratio is greater than 3/1 and aperture diameter is less than 0.5 millimeters.
Claim 7
Dependent Claim
16 words
The method as described in claim 1, wherein the high aspect ratio is greater than 5/1.
Claim 8
Dependent Claim
24 words
The method as described in claim 1, wherein the thin film of copper on the major surface is between 4,000 and 20,000 Angstroms thick.
Claim 9
Dependent Claim
23 words
The method as described in claim 1, wherein the macroscopically discontinuous copper film on the aperture walls is less than 100 Angstroms thick.
Claim 10
Dependent Claim
18 words
The method as described in claim 1, wherein the macroscopically discontinuous copper film is a discontinuous island structure.
Claim 11
Dependent Claim
15 words
The method as described in claim 1, wherein the substrate is a printed circuit board.
Claim 12
Independent Claim
141 words
A method of metallizing high aspect ratio apertures in a printed circuit board, comprising the following steps in the order named: a) providing a printed circuit laminate having apertures therein, the apertures having sidewalls and an aspect ratio greater than 4/1; b) sputtering a thin film of copper on a major surface of the printed circuit laminate and in the apertures, such that the thin film of copper deposited on the major surface is between 4,000 and 20,000 Angstroms thick and such that the thin film of copper deposited on the aperture sidewalls is less than 100 Angstroms thick and macroscopically discontinuous; and c) depositing a layer of electroless copper on the thin film of copper by immersing the printed circuit laminate in an auto-catalytic copper plating bath until a macroscopically continuous layer of copper is formed on the aperture sidewalls.
Claim 13
Independent Claim
141 words
A method of metallizing high aspect ratio apertures in a printed circuit board, comprising the following steps in the order named: a) providing a printed circuit laminate having apertures therein, the apertures having sidewalls and an aspect ratio greater than 4/1; b) sputtering a thin film of copper on a major surface of the printed circuit laminate and in the apertures, such that the thin film of copper deposited on the major surface is between 4,000 and 20,000 Angstroms thick and such that the thin film of copper deposited on the aperture sidewalls is less than 100 Angstroms thick and macroscopically discontinuous; and c) depositing a layer of electroless copper on the thin film of copper by immersing the printed circuit laminate in an auto-catalytic copper plating bath until a macroscopically continuous layer of copper is formed on the aperture sidewalls.
Claim 14
Dependent Claim
22 words
The method as described in claim 11, wherein the auto-catalytic copper plating bath comprises an alkaline solution of copper, formaldehyde and EDTA.
Claim 15
Dependent Claim
27 words
The method as described in claim 11, wherein the auto-catalytic copper plating bath contains trace quantities of palladium, tin or reaction byproducts of palladium, tin or copper.
References Cited (Backward Citations)
US4054483A
Cited
US4521280A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-11-19 | 2000-05-20 | 2000-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-19 | 2004-05-20 | 2004-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-19 | 2008-05-20 | 2008-11-19 | $7700.00 | Window Closed / Lapsed |