GB2257714A - Treated copper foil for copper laminated board of printed wiring board - Google Patents
Treated copper foil for copper laminated board of printed wiring board Download PDFInfo
- Publication number
- GB2257714A GB2257714A GB9204809A GB9204809A GB2257714A GB 2257714 A GB2257714 A GB 2257714A GB 9204809 A GB9204809 A GB 9204809A GB 9204809 A GB9204809 A GB 9204809A GB 2257714 A GB2257714 A GB 2257714A
- Authority
- GB
- United Kingdom
- Prior art keywords
- copper foil
- copper
- foil
- board
- printed wiring
- 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.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/11—Printed elements for providing electric connections to or between printed circuits
- H05K1/111—Pads for surface mounting, e.g. lay-out
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
- H05K3/382—Improvement of the adhesion between the insulating substrate and the metal by special treatment of the metal
- H05K3/383—Improvement of the adhesion between the insulating substrate and the metal by special treatment of the metal by microetching
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/03—Conductive materials
- H05K2201/0332—Structure of the conductor
- H05K2201/0335—Layered conductors or foils
- H05K2201/0355—Metal foils
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/03—Metal processing
- H05K2203/0307—Providing micro- or nanometer scale roughness on a metal surface, e.g. by plating of nodules or dendrites
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/11—Treatments characterised by their effect, e.g. heating, cooling, roughening
- H05K2203/1152—Replicating the surface structure of a sacrificial layer, e.g. for roughening
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
- H05K3/3457—Solder materials or compositions; Methods of application thereof
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
- H05K3/382—Improvement of the adhesion between the insulating substrate and the metal by special treatment of the metal
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Manufacturing Of Printed Wiring (AREA)
- Manufacturing Of Printed Circuit Boards (AREA)
Abstract
The surface of a copper foil 2 is roughened by forming the foil by deposition on a drum previously provided with a rough surface or by soft etching the foil, and the foil is bonded to the insulating board 3 with the rough surface not in contact with the board. The minute uneveness imparted to the copper foil by the roughening increases the surface area enabling a high density of electronic components to be mounted on the board by soldering having strength and reliability. <IMAGE>
Description
"COPPER FOIL FOR COPPER LAMINATED BOARD"
The present invention generally relates to a copper foil superposed on an insulating layer in a copper laminated board which is a material board of printed wiring boards.
During the manufacture of printed wiring boards, a photosensitive ink is applied over a copper laminated board, which is then subjected to a variety of treatments such as exposure of a circuit pattern, development, etching, and solder resist coating. In order to mount electronic components onto the printed wiring board, the lead wires of the electronic components are connected to junction lands of the printed wiring board by means of soldering. The copper laminated board which is used as a material board of the printed wiring board includes an insulating board made of bakelite or glass epoxy resin, and a copper foil thermally contact bonded on the insulating board, or alternatively includes an insulating board made of paper phenol, and copper foil stuck on the insulating board.For manufacturing the copper foil of the copper laminated board, electric wire scraps having a higher purity are dissolved in sulphuric acid to obtain a copper ion solution which is in turn electrolysed. At the time of electrolysation, a drum whose surface is conditioned to be of the order of Ra = 0.43 m is used as a cathode. Metallic copper is electrodeposited onto the surface of the drum while rotating the drum in the copper ion solution, and subsequently the electrodeposited copper foil is successively peeled off the drum to form a rolled raw foil. To obtain a copper laminated board, the raw foil is then superposed on the insulating board in such a manner that a first surface of the foil peeled off or confronting the drum is not in contact with the insulating board while a second surface of the foil opposite to the first surface is bonded to the insulating board.In this lamination, copper oxide is applied onto the surface of the copper foil to be bonded to the insulating board, thereby securing the required bonding performance with respect to the insulating board. Figure 5 of the accompanying drawing shows thus manufactured copper laminated board, in which the first surface (the surface not in contact with the substrate) of the copper foil 51 superposed on the substrate 52 has an evenness of the order of Ra = 0.43 m.
Incidentally, there is a growing tendency for a greater number of chip components to be mounted on the printed wiring board as compared with discrete components, and that the density of the chip components mounted on the surface becomes greater.
While on the contrary, these chip components are recently reduced in size and increased in capacity, which requires smaller junction lands and circuit of the printed wiring board to be loaded with these chip components and electrically connected therewith.
Nevertheless, the copper foil of the copper laminated board which is the material board of the conventional printed wiring board has a substantially even surface, which restricts the surface area of the junction lands or a circuit per unit area. This results in a limitation in mounting strength or connection strength of the electronic components, thus leading to a reduced reliability.
The present invention was conceived in view of the above problems, and seeks to provide a copper foil for a copper laminated board applicable to printed wiring boards which is capable of mounting and connecting miniaturised electronic components having a larger capacity with a higher reliability than hitherto.
The copper foil for copper laminated boards in accordance with the present invention is characterised in that the surface of the copper foil which is not in contact with the insulating board is roughened to form a minute unevenness.
In this manner, the formation of a minute unevenness on the surface of the copper foil increases the surface area of junction lands to be formed in the later treatment, which improves the mounting strength and connection strength of the electronic components and resultantly also improves the reliability thereof.
In this case, a minute unevenness is previously provided on the surface of the drum used in the raw foil producing step, and the unevenness may be transferred onto the film during the manufacture of the raw foil, thereby simultaneously forming the copper foil and the unevenness thereof.
Also, the unevenness may be formed by soft etching the surface of the raw foil, which facilitates the control and management for the provision of the unevenness.
In order that the invention may be better understood, an embodiment thereof will now be described by way of example only, and with reference to the accompanying drawings in which:
Figure 1 is a sectional view of the copper laminated board including a substrate and a copper foil of the present invention superposed on the substrate;
Figure 2 is an explanatory drawing of the process for manufacturing the copper foil in accordance with the present invention;
Figure 3 is a perspective view of the drum for producing a raw copper foIl;
Figure 4 is a sectional view of the printed wiring board formed from the copper laminated board of the present invention; and
Figure 5 is a sectional view of the conventional copper laminated board.
Figure 2 shows the manufacturing process of copper foil in accordance with an embodiment of the present invention. As a copper raw material 21 there is used electric wire scraps having substantially the same purity as electrolytic copper. The copper raw material 21 is dissolved and ionised by sulphuric acid to obtain a copper sulphate solution 22. A drum 23 serving as a cathode is immersed in the copper sulphate solution 22. A copper plate, lead plate, titanium plate or the like is used as an anode 24.
The drum 23 is rotated for electrolysis to electrodeposit metallic copper onto the surface of the drum 23. A copper foil 25 deposited on the surface of the drum 23 is continuously peeled off with the rotation of the drum 23. Figure 3 shows the drum 23 whose surface 23a has a minute unevenness with Ra = 0.5 to 1.0 pm in depth or height formed by means of etching, grinding or the like. Therefore, at least the surface (closer to the drum 23) of the copper foil 25 electrodeposited on the surface 23a of the drum 23 has substantially the same level of minute unevenness (Ra = 0.5 to 1.0 pm) transferred thereon. The copper foil peeled off the drum 23 in this manner is rolled into a raw foil 26 which is in turn drawn for treatment.
Figure 2 shows a series of treatment vessels 27 through which the copper foil 25 travels for the deposition of copper oxide which keeps the adhesive force with an insulating board, the formation of a barrier which imparts a heat-resisting property on the surface thereof, a rust proof coating and the like.
The copper foil 25 which has passed through the treatment vessels 27 is delivered to a roller 29 for applying an adhesive 28 onto the reverse side of the copper foil 25, and is then dried by a drier 30.
Subsequently, the copper foil is cut by a cutter 31 to obtain a thin sheet of copper foil 2. The surface of the thus-formed copper foil sheet 2, which is noncontacting with the insulating board, is roughened with a minute unevenness, and the copper foil sheet 2 is superposed on the insulating board such as bakelite, glass epoxy resin, paper phenol by means of adhesive applied on the reverse side the copper foil sheet 2 for the manufacture of copper laminated boards.
Figure 1 shows a copper laminated board 1 in which the copper foil sheet 2 is integrally laminated on the top surface of a substrate 3. A photosensitive ink is applied onto the slightly uneven surface of the copper foil sheet 2, which is subjected to exposure, development, etching as well as solder resist coating for circuit pattern to produce printed wiring boards.
Figure 4 shows a printed wiring board 4 including a substrate 3 having thereon junction lands 5 and a circuit 6 made of copper foil, and a solder resist 7. The junction lands 5 are loaded with electronic components (not shown) while the circuit 6 is connected to the lead wires of the electronic components. The loading and connection processes are carried out by soldering. The surfaces of the junction lands 5 and the circuit 6 are advantageously provided with a minute unevenness to increase the surface areas thereof, thereby remarkably improving the bonding strength of soldering to enable a highly reliable loading. The increase in the surface areas due to the unevenness facilitates the miniaturisation, which enables the realisation of a high-density circuit.This imparts a satisfactory reliability even to a circuit with a minute width of 100 pm, thus making it possible to cope with a higher density of electronic components. The adhesion of ink for a pattern resist and the solder resist of the printed wiring board is improved to attain a high performance.
In the above embodiment, the minute unevenness is transferred from the surface of the drum onto the copper foil during the raw foil step. In the present invention, however, the copper foil may be roughened by soft etching after the raw foil step to form a minute unevenness on the surface of the copper foil.
The following formulae A and B are each given for an etching agent applicable to this soft etching:
Formula A
98% (W/W) Sulphuric 100 cc/1
Sodium per sulphate or Ammonium
persulphate 120 to 90 g/1
Water Remainder of 1 lit.
Formula B
98% (W/W) Sulphuric 8 to 16 cc/1
Hydrogen peroxide 6 to 12 cc/1
Water Remainder of 1 lit.
The copper foil is immersed in the thusprescribed etching agent for 15 to 30 seconds to roughen the surface thereof, thereby forming a minute unevenness of Ra = 0.3 to 1.0 pm over the entire surface of the copper foil. It will be noted that such soft etching is carried out for the copper foil not subjected to the treatment steps. The roughening of the copper foil surface by such soft etching can provide any degree of unevenness by controlling the formula of the etching agent, immersion time, and the like in addition to the function of the above embodiment. Consequently, the roughening can be executed in accordance with the object.
In the present invention, the surface of the copper foil to be shaped into junction lands and a circuit is roughened to present a minute unevenness, thereby increasing the surface area. This leads to an improved reliability in loading of electronic components and application to a higher-density loading of electronic components.
Claims (5)
1. A copper foil for a copper laminated board comprising an insulating plate, said copper foil being superposed on said insulating plate, and wherein:
one surface of said foil which is not to be in contact with said insulating plate is roughened to form a minute unevenness.
2. A copper foil according to claim 1, wherein said unevenness is transferred from the surface of a drum used in raw foil producing step onto said one side of said copper foil, said surface of said drum being previously provided with a minute unevenness.
3. A copper foil according to claim 1, wherein said unevenness is formed by soft etching the surface of a raw foil.
4. A copper foil according to claim 1, substantially as hereinbefore described.
5. A copper laminated board comprising an insulating plate having a copper foil according to any one of claims 1 to 4 superposed thereon.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3201455A JPH0521951A (en) | 1991-07-16 | 1991-07-16 | Copper foil for copper-clad laminate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9204809D0 GB9204809D0 (en) | 1992-04-15 |
| GB2257714A true GB2257714A (en) | 1993-01-20 |
Family
ID=16441379
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9204809A Withdrawn GB2257714A (en) | 1991-07-16 | 1992-03-04 | Treated copper foil for copper laminated board of printed wiring board |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH0521951A (en) |
| GB (1) | GB2257714A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0618755A1 (en) * | 1993-03-29 | 1994-10-05 | Japan Energy Corporation | Copper foil for printed circuits and process for producing the same |
| EP0844809A3 (en) * | 1996-11-20 | 1999-12-01 | Ibiden Co, Ltd. | Solder resist composition and printed circuit boards |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10988388B2 (en) | 2017-12-04 | 2021-04-27 | Share Light Co., Ltd. | Sterilizing apparatus |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5268971A (en) * | 1975-12-05 | 1977-06-08 | Hitachi Chemical Co Ltd | Method of pretreating adhesion of multiple layers of multiilayer printed circuit board |
| US4073699A (en) * | 1976-03-01 | 1978-02-14 | Hutkin Irving J | Method for making copper foil |
| US4113576A (en) * | 1976-06-17 | 1978-09-12 | Hutkin Irving J | Method of making a thin-copper foil-carrier composite |
| WO1985002969A1 (en) * | 1983-12-19 | 1985-07-04 | Microclad Laminates Limited | Production of copper-clad dielectric boards |
| JPS63183178A (en) * | 1987-01-23 | 1988-07-28 | Nippon Denkai Kk | Copper foil for printed circuit and production thereof |
| WO1988010327A1 (en) * | 1987-06-23 | 1988-12-29 | Olin Corporation | Cathode surface treatment for electroforming metallic foil or strip |
| JPH03276739A (en) * | 1990-03-27 | 1991-12-06 | Hitachi Cable Ltd | Tape carrier for tab and manufacture thereof |
-
1991
- 1991-07-16 JP JP3201455A patent/JPH0521951A/en active Pending
-
1992
- 1992-03-04 GB GB9204809A patent/GB2257714A/en not_active Withdrawn
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5268971A (en) * | 1975-12-05 | 1977-06-08 | Hitachi Chemical Co Ltd | Method of pretreating adhesion of multiple layers of multiilayer printed circuit board |
| US4073699A (en) * | 1976-03-01 | 1978-02-14 | Hutkin Irving J | Method for making copper foil |
| US4113576A (en) * | 1976-06-17 | 1978-09-12 | Hutkin Irving J | Method of making a thin-copper foil-carrier composite |
| WO1985002969A1 (en) * | 1983-12-19 | 1985-07-04 | Microclad Laminates Limited | Production of copper-clad dielectric boards |
| JPS63183178A (en) * | 1987-01-23 | 1988-07-28 | Nippon Denkai Kk | Copper foil for printed circuit and production thereof |
| WO1988010327A1 (en) * | 1987-06-23 | 1988-12-29 | Olin Corporation | Cathode surface treatment for electroforming metallic foil or strip |
| JPH03276739A (en) * | 1990-03-27 | 1991-12-06 | Hitachi Cable Ltd | Tape carrier for tab and manufacture thereof |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0618755A1 (en) * | 1993-03-29 | 1994-10-05 | Japan Energy Corporation | Copper foil for printed circuits and process for producing the same |
| US5552234A (en) * | 1993-03-29 | 1996-09-03 | Japan Energy Corporation | Copper foil for printed circuits |
| EP0844809A3 (en) * | 1996-11-20 | 1999-12-01 | Ibiden Co, Ltd. | Solder resist composition and printed circuit boards |
| EP1796446A3 (en) * | 1996-11-20 | 2007-09-19 | Ibiden Co., Ltd. | Solder resist composition and printed circuit boards |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9204809D0 (en) | 1992-04-15 |
| JPH0521951A (en) | 1993-01-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |