US3677906A - Method and apparatus for producing thin copper foil - Google Patents
Method and apparatus for producing thin copper foil Download PDFInfo
- Publication number
- US3677906A US3677906A US99035A US3677906DA US3677906A US 3677906 A US3677906 A US 3677906A US 99035 A US99035 A US 99035A US 3677906D A US3677906D A US 3677906DA US 3677906 A US3677906 A US 3677906A
- Authority
- US
- United States
- Prior art keywords
- copper
- rhenium
- plated
- copper foil
- drum
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title abstract description 35
- 239000011889 copper foil Substances 0.000 title abstract description 16
- 238000000034 method Methods 0.000 title abstract description 12
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical group [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 abstract description 20
- 229910052702 rhenium Inorganic materials 0.000 abstract description 19
- 238000009713 electroplating Methods 0.000 abstract description 3
- 229910052802 copper Inorganic materials 0.000 description 19
- 239000010949 copper Substances 0.000 description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 6
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 5
- 229910052737 gold Inorganic materials 0.000 description 5
- 239000010931 gold Substances 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 3
- 239000011888 foil Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000007747 plating Methods 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical group ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000008151 electrolyte solution Substances 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 230000006911 nucleation Effects 0.000 description 2
- 238000010899 nucleation Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 244000187656 Eucalyptus cornuta Species 0.000 description 1
- 229920001410 Microfiber Polymers 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 229940067232 ethanol 0.3 ml/ml medicated liquid soap Drugs 0.000 description 1
- XGFJCRNRWOXGQM-UHFFFAOYSA-N hot-2 Chemical compound CCSC1=CC(OC)=C(CCNO)C=C1OC XGFJCRNRWOXGQM-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 108010017584 romiplostim Proteins 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 1
- 229910000406 trisodium phosphate Inorganic materials 0.000 description 1
- 235000019801 trisodium phosphate Nutrition 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D1/00—Electroforming
- C25D1/04—Wires; Strips; Foils
Definitions
- the surface of the rotating drum is rhenium.
- This invention relates in general to a method and apparatus for manufacturing thin copper foils and more particularly to an electrolytic process using a rotating cathode drum to produce ultra-thin copper foils.
- Thin copper foils having a thickness of 0.003 inch or less, free of pinholes, and having a purity of greater than 99 percent are required for printed circuit applications.
- Foils for this purpose are generally produced in an electrolytic process in which copper from a copper anode or a copper containing electrolyte is plated onto a rotating drum, which serves as a cathode, and the foil is peeled off the drum as it rotates.
- the initial processes developed for this purpose employed a lead rotating drum as the cathode. However, the softness of the lead reulted in contamination of the produced copper foil which lead particles. Subsequently stainless steel cathode drums were used to overcome this problem.
- the stainless steel drum must be vary carefully prepared and, even when so prepared, non-conducting stainless steel oxides which are not uniform result in preferential sites for nucleation of the deposited copper resulting in pinhole forma tions in the ultra-thin foils, for example, less than 1 mil.
- the single figure is a schematic representation of an electrolytic plating apparatus suitable for use in the practice of this invention.
- an electrolytic tank 11 contains an electrolytic solution 12 in which is inserted an anode 18 and a cathode 16, the latter including a rotating drum 14 from which electrolytically plated copper foil 20 is peeled by means of a lifting mechanism 21.
- the drum 14 is kept rotating at a relatively slow speed in a counterclockwise direction by means of a motor (not shown).
- the anode 18 was formed of soluble copper and the electrolytic solution was 1 mole of CuSO .5H O, 1 mole of H and 1000 cc. of H 0.
- the lifting mechanism can simply be a driven roller mechanism on which the produced copper foil is wound.
- the cathod drum 14 is a rhenium plated copper rod.
- the copper rod is first wetted with oil and polished using a series of abrasive papers with grit numbers 180, 320, 420, 500, 600 2/0 in succession.
- the polished copper rod is then degreased with a solution of trichlorethylene followed by an alcohol rinse and a cold water rinse.
- the rod is then electro-cleaned with trisodium phosphate and rinsed with cold water. Following this the rod is dipped in a hot 2 percent citric acid solution and again rinsed with cold water.
- the rod is next plated with a gold strike, such as that manufactured under the trade name Sol-Rex Aurobond by Sel-Rex Corp., Nutley, NJ.
- the rod is then further plated with a gold plate to an approximate thickness of of a mil and once more rinsed with cold water.
- the plated gold is polished with water and alumina to a 1 micron finish, washed with green soap and rinsed. It is then buffed with microcloth, degreased with trichlorethylene followed by an alcohol rinse and a deionized cold water rinse.
- the initial step in the rhenium plating is to dip the gold plated copper rod in a 2 percent citric acid solution and then use a distilled water rinse. Rhenium is then plated on at about 65 C. with a current of about ma./ cm. for 18 hours using a platinum anode and a solution of ACR Rhe'nplate (trademark of American Chemical & Refining Co., Waterbury, Conn.) until the rhenium plate has a thickness of 1.5 mil.
- the plating current for producing the copper sheet was 62 amps/ sq. ft. and the resultant copper sheet deposited uniformly on the rhenium plated roll and peeled off readily. Consistently good copper foils of 0.2 mils were thus produced. While in the above example the cathode drum was a rhenium plated copper rod, high density rhenium tubing or a solid rhenium rod made from rhenium powder may also be employed. Using a high density rhenium tubing, copper foils of thicknesses down to 0.113 mil have been successfully produced.
- Apparatus for the electrolytic production of copper foil comprising,
- an electrolyte tank a copper anode having at least a portion of its surface within said electrolyte tank, a rotatable drum having a portion of its surface disposed within said tank, said rotatable drum having a rhenium surface and means to rotate said drum.
- said rotatable drum is formed of an underlying surface of copper on which there has been deposited gold plate with a surface finish of 1 micron, on which a rhenium surface has been plated.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrolytic Production Of Metals (AREA)
Abstract
A PROCESS AND APPARATUS FOR PRODUCING THIN COPPER FOILS BY ELECTROPLATING THE COPPER ONTO A ROTATING DRUM WHICH IS CONNECTED AS A CATHODE. THE SURFACE OF THE ROTATING DRUM IS RHENIUM.
Description
13, 1972 CHlH-CHUNG WANG 3,577,0
METHOD AND APPARATUS FOR PRODUCING THIN COPPER FOIL Filed Dec. 17. 1970 LIFTING MECHANlSM 2| INVENTQR CH|H-CHUNG WANG BY L,
ATTORNEYS United States Patent 7 Claims ABSTRACT OF DISCLOSURE A process and apparatus for producing thin copper foils by electroplating the copper onto a rotating drum which is connected as a cathode. The surface of the rotating drum is rhenium.
FIELD OF THE INVENTION This invention relates in general to a method and apparatus for manufacturing thin copper foils and more particularly to an electrolytic process using a rotating cathode drum to produce ultra-thin copper foils.
BACKGROUND OF THE INVENTION Thin copper foils having a thickness of 0.003 inch or less, free of pinholes, and having a purity of greater than 99 percent are required for printed circuit applications. Foils for this purpose are generally produced in an electrolytic process in which copper from a copper anode or a copper containing electrolyte is plated onto a rotating drum, which serves as a cathode, and the foil is peeled off the drum as it rotates. The initial processes developed for this purpose employed a lead rotating drum as the cathode. However, the softness of the lead reulted in contamination of the produced copper foil which lead particles. Subsequently stainless steel cathode drums were used to overcome this problem. However, the stainless steel drum must be vary carefully prepared and, even when so prepared, non-conducting stainless steel oxides which are not uniform result in preferential sites for nucleation of the deposited copper resulting in pinhole forma tions in the ultra-thin foils, for example, less than 1 mil.
Various techniques have been employed to overcome the deficiency of the pinhole formation resulting from the drums. Platinum has been employed as a surface for cathode drums. Nickel coated steel mandrels have also been used to produce copper foils. Some success in producing pinhole free copper foils at thicknesses down to about 0.0007 inch has been achieved using especially prepared chromium-coated drums. All the above materials have a common shortcoming of having an electrically nonconductive oxide fihn which causes preferential nucleation of deposited copper resulting in pinholes.
SUMMARY OF THE INVENTION DESCRIPTION OF THE DRAWINGS The single figure is a schematic representation of an electrolytic plating apparatus suitable for use in the practice of this invention.
3,677,906 P atented July 18, 1972 DESCRIPTION OF PREFERRED EMBODIMENTS With reference now to the drawing, an electrolytic tank 11 contains an electrolytic solution 12 in which is inserted an anode 18 and a cathode 16, the latter including a rotating drum 14 from which electrolytically plated copper foil 20 is peeled by means of a lifting mechanism 21. The drum 14 is kept rotating at a relatively slow speed in a counterclockwise direction by means of a motor (not shown). It will be understoodthat the apparatus illustra'tedis schematic in form and that the actual physical apparatus may take any of several conventional forms well known in the art. In one example, the anode 18 was formed of soluble copper and the electrolytic solution was 1 mole of CuSO .5H O, 1 mole of H and 1000 cc. of H 0. The lifting mechanism can simply be a driven roller mechanism on which the produced copper foil is wound.
In one embodiment, the cathod drum 14 is a rhenium plated copper rod. The copper rod is first wetted with oil and polished using a series of abrasive papers with grit numbers 180, 320, 420, 500, 600 2/0 in succession. The polished copper rod is then degreased with a solution of trichlorethylene followed by an alcohol rinse and a cold water rinse. The rod is then electro-cleaned with trisodium phosphate and rinsed with cold water. Following this the rod is dipped in a hot 2 percent citric acid solution and again rinsed with cold water. The rod is next plated with a gold strike, such as that manufactured under the trade name Sol-Rex Aurobond by Sel-Rex Corp., Nutley, NJ. and then rinsed with a deionized cold water. The rod is then further plated with a gold plate to an approximate thickness of of a mil and once more rinsed with cold water. The plated gold is polished with water and alumina to a 1 micron finish, washed with green soap and rinsed. It is then buffed with microcloth, degreased with trichlorethylene followed by an alcohol rinse and a deionized cold water rinse.
The initial step in the rhenium plating is to dip the gold plated copper rod in a 2 percent citric acid solution and then use a distilled water rinse. Rhenium is then plated on at about 65 C. with a current of about ma./ cm. for 18 hours using a platinum anode and a solution of ACR Rhe'nplate (trademark of American Chemical & Refining Co., Waterbury, Conn.) until the rhenium plate has a thickness of 1.5 mil.
In one example, the plating current for producing the copper sheet was 62 amps/ sq. ft. and the resultant copper sheet deposited uniformly on the rhenium plated roll and peeled off readily. Consistently good copper foils of 0.2 mils were thus produced. While in the above example the cathode drum was a rhenium plated copper rod, high density rhenium tubing or a solid rhenium rod made from rhenium powder may also be employed. Using a high density rhenium tubing, copper foils of thicknesses down to 0.113 mil have been successfully produced.
What is claimed is:
1. In a process for preparing thin copper foils, the improvement comprising,
electro-depositing the copper on a rotating electrode having a rhenium surface.
2. A process in accordance with claim 1 wherein the rotating rhenium electrode is formed of a copper roll having rhenium plated thereon.
3. A process in accordance with claim 1 wherein the rotating electrode is formed of a high density rhenium tubing.
4. A process in accordance with claim 1 wherein the copper is plated from a soluble anode in a plating solution of 1 mole CuSO .5H O, 1 mole H 80, and 1000 cc. of H 0.
5. Apparatus for the electrolytic production of copper foil comprising,
an electrolyte tank, a copper anode having at least a portion of its surface within said electrolyte tank, a rotatable drum having a portion of its surface disposed within said tank, said rotatable drum having a rhenium surface and means to rotate said drum. 6. Apparatus in accordance with claim 5 wherein said rotatable drum is formed of an underlying surface of copper on which there has been deposited gold plate with a surface finish of 1 micron, on which a rhenium surface has been plated.
7. Apparatus in accordance with claim 5 wherein said rotatable drum is formed of a high density rhenium tubing or high density rhenium. I
References Cited UNITED STATES PATENTS Wilkins 204-28l Yates 204l3 Macon 204l3 Sternfels 204-43 Brown 204-'6 Harrison 204l3 Edison 204-13 US. Cl. X.R.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US9903570A | 1970-12-17 | 1970-12-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3677906A true US3677906A (en) | 1972-07-18 |
Family
ID=22272210
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US99035A Expired - Lifetime US3677906A (en) | 1970-12-17 | 1970-12-17 | Method and apparatus for producing thin copper foil |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US3677906A (en) |
| JP (1) | JPS5519991B1 (en) |
| CA (1) | CA978893A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3930962A (en) * | 1975-02-21 | 1976-01-06 | Kennecott Copper Corporation | Process and apparatus for producing thin copper foils on a molybdenum or tzm alloy drum |
| US20060211247A1 (en) * | 2005-03-18 | 2006-09-21 | Hitachi Global Storage Technologies Netherlands B.V. | Lapping of gold pads in a liquid medium for work hardening the surface of the pads |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6229535U (en) * | 1985-08-01 | 1987-02-23 |
-
1970
- 1970-12-17 US US99035A patent/US3677906A/en not_active Expired - Lifetime
-
1971
- 1971-12-09 CA CA129,771A patent/CA978893A/en not_active Expired
- 1971-12-17 JP JP10199471A patent/JPS5519991B1/ja active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3930962A (en) * | 1975-02-21 | 1976-01-06 | Kennecott Copper Corporation | Process and apparatus for producing thin copper foils on a molybdenum or tzm alloy drum |
| US20060211247A1 (en) * | 2005-03-18 | 2006-09-21 | Hitachi Global Storage Technologies Netherlands B.V. | Lapping of gold pads in a liquid medium for work hardening the surface of the pads |
| US7538035B2 (en) * | 2005-03-18 | 2009-05-26 | Hitachi Global Storage Technologies Netherlands B.V. | Lapping of gold pads in a liquid medium for work hardening the surface of the pads |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5519991B1 (en) | 1980-05-30 |
| CA978893A (en) | 1975-12-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: KENNECOTT MINING CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:KENNECOTT CORPORATION;REEL/FRAME:004815/0036 Effective date: 19870220 Owner name: KENNECOTT CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:KENNECOTT COPPER CORPORATION;REEL/FRAME:004815/0016 Effective date: 19800520 Owner name: KENNECOTT CORPORATION, 200 PUBLIC SQUARE, CLEVELAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:KENNECOTT MINING CORPORATION;REEL/FRAME:004815/0063 Effective date: 19870320 |
|
| AS | Assignment |
Owner name: GAZELLE CORPORATION, C/O CT CORPORATION SYSTEMS, C Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:RENNECOTT CORPORATION, A DE. CORP.;REEL/FRAME:005164/0153 Effective date: 19890628 |
|
| AS | Assignment |
Owner name: KENNECOTT UTAH COPPER CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:GAZELLE CORPORATION;REEL/FRAME:005604/0237 Effective date: 19890630 |