Patent US5197294A successfully refreshed from Google Patents.
Patent US4898651A successfully refreshed from Google Patents.
US4898651A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anodic coatings on aluminum for circuit packaging
Assignee: International Business Machines Corp
•
Filing: 1989-08-25
•
Granted: 1990-02-06
•
Expires: 2009-08-25
Abstract
Abstract A process for preparing aluminum alloy substrates for use in electrical packaging includes anodizing in an aqueous bath solution containing sulfuric acid, citric acid, urea, and ammoniated colloidal silica; the latter three components being a complexing agent, a leveling agent and a stabilizing agent, respectively, so as to result in an oxide layer having an amorphous structure which eliminates the necessity of sealing thick anodic coating.
Inventors
- 👤 Issa S. Mahmoud
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:30
CPC Classifications
C; C25; C25D; C25D11/00; C25D11/02; C25D11/04; C25D11/16; C25D11/06; H; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/05; H05K1/053
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
139 words
A method of preparing aluminum alloy substrates for use in electrical packaging applications comprising the sequential steps of: (a) cleaning aluminum alloy workpieces; (b) polishing the aluminum alloy workpieces; (c) rinsing the polished aluminum alloy workpieces; (d) anodizing the aluminum alloy workpieces in an electrochemical cell in which the aluminum alloy workpieces are made positive and the cell solution comprises: deionized water, sulfuric acid, a complexing agent, urea and ammoniated colloidal silica; at a temperature of about 5 to about 15 degrees centigrade at a current density initially of about 30 to about 50 amps per square foot for a time determined as a function of the desired thickness in accordance with thickness=15 Angstroms per second times seconds; (e) rinsing the anodized aluminum alloy workpieces in flowing deionized water; and (f) drying the anodized aluminum workpieces in forced air.
Claim 2
Independent Claim
139 words
A method of preparing aluminum alloy substrates for use in electrical packaging applications comprising the sequential steps of: (a) cleaning aluminum alloy workpieces; (b) polishing the aluminum alloy workpieces; (c) rinsing the polished aluminum alloy workpieces; (d) anodizing the aluminum alloy workpieces in an electrochemical cell in which the aluminum alloy workpieces are made positive and the cell solution comprises: deionized water, sulfuric acid, a complexing agent, urea and ammoniated colloidal silica; at a temperature of about 5 to about 15 degrees centigrade at a current density initially of about 30 to about 50 amps per square foot for a time determined as a function of the desired thickness in accordance with thickness=15 Angstroms per second times seconds; (e) rinsing the anodized aluminum alloy workpieces in flowing deionized water; and (f) drying the anodized aluminum workpieces in forced air.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the cleaning step (a) includes immersing in a chlorinated solvent.
Claim 4
Dependent Claim
45 words
The method of claim 1 wherein the cleaning step (a) includes immersing in an alkaline solution having a pH in the range of about 8 to 10, at a temperature in the range from about 50 to about 65 degrees centigrade, and rinsing in water.
Claim 5
Independent Claim
63 words
The method of claims 1,2 or 3 wherein the polishing step (b) comprises: immersing the workpieces for about 2 to 3 minutes in a bath containing, per liter, 784 ml phosphoric acid, 98 ml nitric acid, 40 grams sodium nitrate, and 118 ml water, while said bath is maintained at a temperature in the range from about 80 to about 90 degrees centigrade.
Claim 6
Dependent Claim
42 words
The method of claim 1 wherein the rinsing step (c) comprises: placing the workpieces in flowing deionized water at a temperature in a range from about 120 to about 130 degrees fahrenheit for a period of about 1 to about 2 minutes.
Claim 7
Dependent Claim
38 words
The method of claim 1 wherein the anodizing step (d) includes a cell solution containing per liter: 974 ml deionized water, 20 ml sulfuric acid, 5.5 grams complexing agent, 3.0 grams urea and 6.0 ml ammoniated colloidal silica.
References Cited (Backward Citations)
US3935349A
Cited
US3985629A
Cited
US4478689A
Cited
US4589925A
Cited
US4406757A
Cited
US4439287A
Cited
US4606796A
Cited
US4481083A
Cited
US4507179A
Cited
US4539146A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-05 | 1993-08-07 | 1994-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-05 | 1997-08-07 | 1998-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-05 | 2001-08-07 | 2002-02-06 | $7700.00 | Window Closed / Lapsed |