GB2206451A - Substrates for circuit panels - Google Patents
Substrates for circuit panels Download PDFInfo
- Publication number
- GB2206451A GB2206451A GB8708457A GB8708457A GB2206451A GB 2206451 A GB2206451 A GB 2206451A GB 8708457 A GB8708457 A GB 8708457A GB 8708457 A GB8708457 A GB 8708457A GB 2206451 A GB2206451 A GB 2206451A
- Authority
- GB
- United Kingdom
- Prior art keywords
- acid
- substrate
- circuit
- anodised
- surface layer
- 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.)
- Pending
Links
- 239000000758 substrate Substances 0.000 title claims abstract description 44
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000004411 aluminium Substances 0.000 claims abstract description 25
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 25
- 229910052751 metal Inorganic materials 0.000 claims abstract description 17
- 239000002184 metal Substances 0.000 claims abstract description 17
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 3
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims abstract description 3
- 239000011777 magnesium Substances 0.000 claims abstract description 3
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 3
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 3
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims abstract description 3
- 239000010936 titanium Substances 0.000 claims abstract description 3
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 3
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 3
- 239000002344 surface layer Substances 0.000 claims abstract 6
- 238000000034 method Methods 0.000 claims description 39
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 12
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 9
- 239000001117 sulphuric acid Substances 0.000 claims description 9
- 235000011149 sulphuric acid Nutrition 0.000 claims description 9
- 150000001991 dicarboxylic acids Chemical class 0.000 claims description 6
- 239000003792 electrolyte Substances 0.000 claims description 6
- -1 sulpho Chemical class 0.000 claims description 5
- YQUVCSBJEUQKSH-UHFFFAOYSA-N 3,4-dihydroxybenzoic acid Chemical compound OC(=O)C1=CC=C(O)C(O)=C1 YQUVCSBJEUQKSH-UHFFFAOYSA-N 0.000 claims description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 4
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 claims description 4
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 claims description 4
- 239000000976 ink Substances 0.000 claims description 4
- 235000006408 oxalic acid Nutrition 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- 239000012670 alkaline solution Substances 0.000 claims description 3
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims description 3
- 239000004327 boric acid Substances 0.000 claims description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical class OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 claims description 3
- 239000004020 conductor Substances 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- 239000007789 gas Substances 0.000 claims description 3
- YCPXWRQRBFJBPZ-UHFFFAOYSA-N 5-sulfosalicylic acid Chemical group OC(=O)C1=CC(S(O)(=O)=O)=CC=C1O YCPXWRQRBFJBPZ-UHFFFAOYSA-N 0.000 claims description 2
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 claims description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 2
- 239000011521 glass Substances 0.000 claims description 2
- 239000012535 impurity Substances 0.000 claims description 2
- 239000001301 oxygen Substances 0.000 claims description 2
- 229910052760 oxygen Inorganic materials 0.000 claims description 2
- 230000001681 protective effect Effects 0.000 claims description 2
- 238000007650 screen-printing Methods 0.000 claims description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 2
- 239000000243 solution Substances 0.000 claims description 2
- IIACRCGMVDHOTQ-UHFFFAOYSA-N sulfamic acid Chemical compound NS(O)(=O)=O IIACRCGMVDHOTQ-UHFFFAOYSA-N 0.000 claims description 2
- RYCLIXPGLDDLTM-UHFFFAOYSA-J tetrapotassium;phosphonato phosphate Chemical compound [K+].[K+].[K+].[K+].[O-]P([O-])(=O)OP([O-])([O-])=O RYCLIXPGLDDLTM-UHFFFAOYSA-J 0.000 claims description 2
- 239000010409 thin film Substances 0.000 claims description 2
- 238000001771 vacuum deposition Methods 0.000 claims description 2
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 claims 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims 3
- RTBFRGCFXZNCOE-UHFFFAOYSA-N 1-methylsulfonylpiperidin-4-one Chemical compound CS(=O)(=O)N1CCC(=O)CC1 RTBFRGCFXZNCOE-UHFFFAOYSA-N 0.000 claims 1
- JFCQEDHGNNZCLN-UHFFFAOYSA-N anhydrous glutaric acid Natural products OC(=O)CCCC(O)=O JFCQEDHGNNZCLN-UHFFFAOYSA-N 0.000 claims 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 claims 1
- 239000011976 maleic acid Substances 0.000 claims 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 claims 1
- 239000010410 layer Substances 0.000 abstract 2
- 239000010408 film Substances 0.000 description 23
- 238000000576 coating method Methods 0.000 description 11
- 230000004888 barrier function Effects 0.000 description 10
- 238000007743 anodising Methods 0.000 description 7
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 6
- 238000004544 sputter deposition Methods 0.000 description 5
- LTPBRCUWZOMYOC-UHFFFAOYSA-N Beryllium oxide Chemical compound O=[Be] LTPBRCUWZOMYOC-UHFFFAOYSA-N 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 230000015556 catabolic process Effects 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000007772 electroless plating Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 238000004070 electrodeposition Methods 0.000 description 1
- 238000005323 electroforming Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000010574 gas phase reaction Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 239000004922 lacquer Substances 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002488 metal-organic chemical vapour deposition Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 230000007096 poisonous effect Effects 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
- H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
- H01L23/3736—Metallic materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4814—Conductive parts
- H01L21/4871—Bases, plates or heatsinks
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/12—Mountings, e.g. non-detachable insulating substrates
- H01L23/14—Mountings, e.g. non-detachable insulating substrates characterised by the material or its electrical properties
- H01L23/142—Metallic substrates having insulating layers
-
- 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
- H05K1/0201—Thermal arrangements, e.g. for cooling, heating or preventing overheating
- H05K1/0203—Cooling of mounted components
-
- 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
- H05K1/03—Use of materials for the substrate
- H05K1/05—Insulated conductive substrates, e.g. insulated metal substrate
- H05K1/053—Insulated conductive substrates, e.g. insulated metal substrate the metal substrate being covered by an inorganic insulating layer
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
-
- 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
- H05K1/09—Use of materials for the conductive, e.g. metallic pattern
- H05K1/092—Dispersed materials, e.g. conductive pastes or inks
-
- 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
- H05K2203/0315—Oxidising metal
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Power Engineering (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Insulated Metal Substrates For Printed Circuits (AREA)
Abstract
Printed or hybrid circuits are formed on a metal substrate having an anodised surface layer, the substrate serving as a heat sink and the anodised layer forming a black body radiator. The circuit may be preformed or may be deposited directly on to the anodised layer. The substrate may be made of aluminium, titanium, tantalum, zirconium or magnesium.
Description
Circuit Panels
This invention relates to anodisable metal substrates for use in circuit panels and particularly, but not exclusively to substrates for anodised hybrid circuit panels wherein an anodic film produced on the surface of the substrate serves as a heat sink, the circuit being deposited directly upon the anodised layer.
Known printed circuit board assemblies have a resin or plastic base that gets hot. To overcome this problem, it is known to interleave the printed circuit boards with metal panels, usually aluminium panels, to remove the heat. Alternatively the aluminium itself is used as the base the circuit being produced by electrodeposition onto the aluminium, so that the circuit and heat sink are one structure, an anodic layer on the metal providing the insulation previously supplied by a phenolic or epoxy board.
The object of the invention is to provide an inexpensive substrate which has good heat emissivity characteristics and superior properities to known substrates and whose properties can be modified according to the requirements of the particular circuit to be produced, using a method suitable for the required circuit.
A further object of this invention is to provide a drilled and anodised panel onto which adheres a preformed metal circuit. The preforming being achieved by punching, chemical milling or electroforming.
The important characteristics of a substrate are the mechanical and thermal properties. Good mechanical strength is required along with high thermal conductivity/emissivity1 for heat dissipation, and a low coefficient of thermal expansion for stability. The majority of thick film circuit manufacturers use an alumina substrate of 90-99% pure alumina. Aluminium loses heat by convection and conduction. However, under the same conditions anodised aluminium loses considerably more heat than bare aluminium because anodised aluminium also loses heat by radiation and can approach the theoretical ideal of a perfect radiator, for example:
Heat loss
Polished Aluminium 4.3-6.4%
Anodised Aluminium 38-92%
Radiation increases with the film thickness, thus the heat loss properties of the substrate can be changed to meet the required characteristics.
As anodised aluminium is a black body radiator it minimises the problem of the differing coefficient of linear expansion for aluminium and the anodic film.
The use of alumina as a substrate is also limited with respect size because of the problem of maintaining surface flatness over large areas without resorting to expensive treatments such as grinding and lapping.
The following is a summary of characteristics of the commonly used substrates and anodised aluminium details of which are shown in the attached table:
Substrate Characteristics
Alumina Limited by size, breakable
Porcelanizied steel Expansion problems, heavy.
Ion migration from porcelain
into circuit material.
Keralloy As above
Beryllia Good heat characteristics,
very expensive, poisonous
Anodised Aluminium Heat loss characteristics better
than alumina. Cheap. No limit to
size.
Anodising is carried out by making the metal which is to form the substrate the anode in an electrolytic cell and passing an electric current until the desired film thickness is obtained. To obtain the required physical properties in the anodic film the parameters of the anodising electrolyte have to be controlled. These are composition, temperature, agitation, current density, current waveform and time.
The three commonly used electrolytes for producing anodic films are sulphuric acid, chromic acid and oxalic acid. They produce anodic films differing in appearance and physical properties. Many other electrolytes have been used, some commercially. Examples are sulphamic acid, phosphoric acid, saturated dicarboxylic acids (Glutaric, malonic, oxalic) unsaturated dicarboxylic acids (maleic), alpha hydroxy carboxylic acids (citric), sulpho derivatives such as sulpho-salicylic acid and hydroxy aromatic acids ie, protocatechuic acid.
The anodising process chosen will have an effect on the properties of the anodic film such as hardness, porosity, heat loss, di-electric constant and breakdown voltage. In general, the anodic film consists of an amorphous barrier layer in contact with the aluminium.
Onto this will grow a more structured layer. In the case of the sulphuric acid process the structure layer consists of a hexagonal columnar growth perpendicular to the barrier layer. It has a degree of porosity that allows dyeing during the product of a circuit to take place.
Other electrolytes produce varying degrees of porosity.
The choice of electrolyte has an effect on such properties as the ratio of barrier layer to columnar growth, hardness, porosity, dielectric constant, breakdown voltage, and heat emissivity etc.
The barrier layer prevents access of aggressive ions to the aluminium metal that is underneath; it also provides electrical insulation. The film can be 'tailored' to have a sufficient thickness of barrier layer to provide the required insulation value and an adequate amount of columnar growth to create adhesion of the circuit to the substrate.
The properties of the substrate can, therefore, be controlled to suit the product requirements.
In one embodiment of the present invention, the substrate is anodised using the chromic acid anodising process. The process gives thin flexible coatings of about 2.5 microns. The coating is compact and flexible and is useful where the requirement for heat emission is limited.
In another embodiment of the invention, the anodic film is produced using -the sulphuric acid process. This produces anodic films of thickness in the range of 1-100 microns and the ratio of outward growth to barrier layer can be altered by altering the operating conditions.
However, it can never be a 100% barrier layer. Coatings from the sulphuric acid process can be used for replacing ordinary printed circuit laminates or where a great amount of heat has to be dissipated. For a printed circuit panel replacement a 25 micron coating from the sulphuric acid process would suffice. For losing a lot of heat a 50-80 micron coating would be used. Thicker coatings generally give higher values for breakdown voltages and di-electric constants. However, the sealing method will influence these values.
In another embodiment of the invention, the anodic film is produced by a sulphuric acid bath of strength 10% vol/vol which contains aluminium, copper, and trace impurities and the anodising process is carried out at a temperature of 70'F and a current density of 10 amperes/sq. ft. Thicker coatings are produced, according to the invention, by using the same bath at a temperature of 0'C and with a higher current density. As the film is produced anodically it is also being dissolved chemically; lowering the temperature reduces the chemical dissolution so that more film is produced for the same amount of current. At the 2.50 micron range the chromic acid film is superior to the sulphuric.
In another embodiment, the oxalic acid process is used to produce the film as an alternative to the sulphuric acid process.
In another embodiment of the invention boric acid/borate solutions are used to produce the barrier layer coatings. This boric acid process is an "all barrier" process; the coatings are very thin.
In an other embodiment of the invention alkaline solutions, such as sodium carbonate or potassium pyrophosphate, are used to produce the barrier layer coatings.
In another embodiment of the invention a dense oxide film such as that produced by anodising, is produced on the substrate, by using a gas plasma in an atmosphere of oxygen or by using high pressure steam on the heat substrate.
For most ' requirements an anodised aluminium substrate will be preferred, but any other anodisable metal such as titanium, tantalum, zirconium or magnesium may be employed for some applications.
After anodising the substrate a circuit is then produced on this anodised substrate.
Thick film hybrid circuits are manufactured by screen printing conductor, resistor and protective materials in the form of special inks and glasses onto the anodised aluminium substrate. Each of the inks is then subjected to a firing process at a controlled temperature.
During the manufacture the resistors are trimmed to specific values, components such as integrated circuits are attached to the conductor material by microsoldering techniques. Leads are fitted to the terminal pads and the whole assembly is encapsulated in resin for protection.
The thin film circuits required by some electronic devices can be produced on the anodised substrate, the vacuum deposition techniques providing a variety of methods for achieving this. Sputtering is an example of a vacuum technique in which in vacuo metals are deposited onto the anodised aluminium. Patterns are produced by sputtering through a mask or sputtering all over the substrate and then etching defined areas by laser or ion gun.
Other vacuum techniques include magnetron Sputtering which is faster than sputtering and gives thicker coats,
Vapour Deposition in which the metal is vaporised in a low vacuum to coat the substrate, Ion Plating which is a combination of vapour deposition and sputtering, Chemical
Vapour Deposition which employs two reactive gases and a carrier gas to produce a non-volatile material which deposits onto the substrate, Metal Organic Chemical Vapour
Deposition in which metals are made volatile by adding alkyl groups to them, Plasma deposition where an involatile material is produced by gas phase reactions in a glow discharge, the involatile material then depositing on the heated substrate.In Wet and Dry Combination processes either the anodised substrate is coated with resin, adhesive or lacquer and then plated with electroless nickel or copper, the circuit pattern is then being put down and any unwanted material etched away, or the circuit pattern is printed onto the anodised substrate with a special ink that initiates electroless plating. The processes initiated in the dry mode may be continued by electro/chemical plating. The circuit is resin coated with through connections and may be repeated to form a layered circuit. These processes also apply to circuits started by electroplating or electroless plating.
Properties of Anodised Aluminium compared with other materials.
Property Anodised Sapphire Sintered Sintered Keralloy aluminium (A1203) Alumina Beryllia (Al2 Os (A1203 Density 2.5-3.0 9 3.98 Z 3.6-3.82 2.85 z 7.22 Purity % 99 - 100 100 z 92-99.5 99.5 Linear 5g 4.5-5.3 6.0 6.5 11.0 expel x 10 6 in/ cbare x- 10 sinlo, 3 Electrical 132 z 1.33ohm resistivity 4101s 10 ohm/c#2/cm my2 /metre Surface finish full choice 0.6 .1 t Flexural - - - strength ASTM.F417.78 Volume Resistivity ASTM1829-66 8109 (3000 c) ohm/cm Dielectric (PERMITTIVITY constant ASTM D 150.74 # 11.8-15.4 8 9.5@25 c Dielectric strength < 3 ASTM D150-74 9500v-10 680v/ 9 lKV.D.C.
(.025" ) 0.001 Loss tangent ss004.0010 (lhz-100MHz) Size ANY 4" x 4" Thickness ANY .0015-.0030" Cost Impact resistance Good poor poor Good Thermal ~ I conductivity 810f.05 X .07 l .52 n.52 Cal.Cm-i.Sec-i2610f.15 .06 .40 deg-lc EMISSIVITY 10 coating =80% and
increases
with anodic
thickness.
Approaches
black body
condition.
Other values:
polished 10
aluminium 4 1 #film 30
3y #film 70 lop film 80
Perfect
Black body
= 100
Claims (19)
- Claims: 1. A circuit structure including a metal substrate having an anodic surface layer such that the substrate and heat sink are one structure onto which the circuit is applied wherein the substrate has predetermined characteristics and properties.
- 2. A circuit structure according to claim 1, wherein the substrate is an anodisable metal.
- 3. A circuit structure according to claim 2, wherein the substrate is Aluminium, Titanium, Tantalum, Zirconium or Magnesium.
- 4. A circuit structure according to claim 1, 2 or 3, wherein the metal substrate is perforated and anodised.
- 5. A circuit structure according to claim 4, wherein the circuit is preformed.
- 6. A method of producing a circuit structure including the steps of forming an anodised surface layer upon a metal substrate using a predetermined process and conditions and applying the circuit directly onto the anodised surface of the substrate.
- 7. A method according to claim 6, wherein the metal substrate is anodised using sulphuric acid, chromic acid, oxalic acid, sulphamic acid, phosphoric acid, saturated dicarboxylic acid, unsaturated dicarboxylic acid, alpha hydroxy carboxylic acid, or sulpho derivative as an electrolyte.
- 8. A method according to claim 7, wherein the saturated dicarboxylic acid is glutaric, malonic or oxalic acid.
- 9. A method according to claim 7, wherein the unsaturated dicarboxylic acid is maleic acid.
- 10. A method according to claim 7, wherein the alpha hydroxy carboxylic acid is citric acid.
- 11. A method according to claim 7, wherein the sulpho derivative is sulpho-salicylic acid, hydroxy aromatic acid or protocatechuic acid.
- 12. A method according to claim 6, wherein the metal substrate is anodised using a sulphuric acid bath of strength 10% vol/vol which contains aluminium, copper, and trace impurities, at a temperature of 700F and a current density of 10 amps/sq.ft.
- 13. A method according to claim 6, wherein the surface layer is formed using a boric acid/borate solution.
- 14. A method according to claim 6, wherein the surface layer is formed using an alkaline solution.
- 15. A method according to claim 6, wherein the alkaline solution is sodium carbonate or potassium pyrophosphate.
- 16. A method according to claim 6, wherein the surface layer is formed by using a gas plasma in an atmosphere of oxygen or by using high pressure steam on the substrate.
- 17. A method according to any one of claims 6 to 16, wherein the circuit is a hybrid circuit which is produced by screen printing conductor, resistor and protective materials in the form of inks and glasses onto said anodised substrate.
- 18. A method according to any one of claims 6 to 16, wherein the circuit is a thin film circuit which is produced by vacuum deposition techniques.
- 19. A method according to claim 18, wherein said
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8708457A GB2206451A (en) | 1987-04-09 | 1987-04-09 | Substrates for circuit panels |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8708457A GB2206451A (en) | 1987-04-09 | 1987-04-09 | Substrates for circuit panels |
Publications (2)
Publication Number | Publication Date |
---|---|
GB8708457D0 GB8708457D0 (en) | 1987-05-13 |
GB2206451A true GB2206451A (en) | 1989-01-05 |
Family
ID=10615496
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB8708457A Pending GB2206451A (en) | 1987-04-09 | 1987-04-09 | Substrates for circuit panels |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2206451A (en) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3910699A1 (en) * | 1989-04-03 | 1990-10-04 | Omt Oberflaechen Materialtech | Printed circuit board for integrated circuits |
FR2646311A1 (en) * | 1989-04-24 | 1990-10-26 | Pechiney Recherche | ISOLATED METAL SUBSTRATES AND PROCESS FOR PRODUCING THESE SUBSTRATES |
EP0504532A1 (en) * | 1991-03-22 | 1992-09-23 | PECHINEY RECHERCHE (Groupement d'Intérêt Economique géré par l'ordonnance du 23 Septembre 1967) | Material for passive electronic components |
US5230788A (en) * | 1989-04-24 | 1993-07-27 | Pechiney Recherche | Insulated metal substrates and process for the production thereof |
EP0936849A1 (en) * | 1998-02-17 | 1999-08-18 | Pressac Interconnect Limited | Printed circuit assembly and method of making the same |
US6448510B1 (en) * | 1997-05-20 | 2002-09-10 | Micro Components Ltd. | Substrate for electronic packaging, pin jig fixture |
US6670704B1 (en) | 1998-11-25 | 2003-12-30 | Micro Components Ltd. | Device for electronic packaging, pin jig fixture |
EP1587348A1 (en) * | 2004-03-30 | 2005-10-19 | Feng Chia University | Conductive base board |
WO2007091976A1 (en) * | 2006-02-10 | 2007-08-16 | Opulent Electronics International Pte Ltd | Anodised aluminium, dielectric, and method |
WO2007133074A1 (en) * | 2006-05-12 | 2007-11-22 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | A process for preparing a heatsink system and heatsink system obtainable by said process |
WO2008021269A2 (en) * | 2006-08-11 | 2008-02-21 | E. I. Du Pont De Nemours And Company | Device chip carriers, modules, and methods of forming thereof |
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GB1229418A (en) * | 1967-08-03 | 1971-04-21 | ||
GB1591895A (en) * | 1977-12-12 | 1981-07-01 | Smolko G G | Electronic devices |
GB2080630A (en) * | 1980-08-21 | 1982-02-03 | Ingram & Glass Ltd | Printed circuit panels |
EP0153098A2 (en) * | 1984-02-14 | 1985-08-28 | Shin-Etsu Chemical Co., Ltd. | Copper foil laminate for use as a base plate or substrate for electronic devices |
GB2162694A (en) * | 1984-08-04 | 1986-02-05 | British Aerospace | Printed circuits |
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1987
- 1987-04-09 GB GB8708457A patent/GB2206451A/en active Pending
Patent Citations (5)
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GB1229418A (en) * | 1967-08-03 | 1971-04-21 | ||
GB1591895A (en) * | 1977-12-12 | 1981-07-01 | Smolko G G | Electronic devices |
GB2080630A (en) * | 1980-08-21 | 1982-02-03 | Ingram & Glass Ltd | Printed circuit panels |
EP0153098A2 (en) * | 1984-02-14 | 1985-08-28 | Shin-Etsu Chemical Co., Ltd. | Copper foil laminate for use as a base plate or substrate for electronic devices |
GB2162694A (en) * | 1984-08-04 | 1986-02-05 | British Aerospace | Printed circuits |
Non-Patent Citations (1)
Title |
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WO A1 85/02750 * |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3910699A1 (en) * | 1989-04-03 | 1990-10-04 | Omt Oberflaechen Materialtech | Printed circuit board for integrated circuits |
FR2646311A1 (en) * | 1989-04-24 | 1990-10-26 | Pechiney Recherche | ISOLATED METAL SUBSTRATES AND PROCESS FOR PRODUCING THESE SUBSTRATES |
EP0395544A1 (en) * | 1989-04-24 | 1990-10-31 | Société Anonyme de Traitement des Métaux et Alliages (SATMA) | Insulated metallic substrates and method of making these substrates |
US5112668A (en) * | 1989-04-24 | 1992-05-12 | Pechiney Recherche | Insulated metal substrates and process for the production thereof |
US5230788A (en) * | 1989-04-24 | 1993-07-27 | Pechiney Recherche | Insulated metal substrates and process for the production thereof |
EP0504532A1 (en) * | 1991-03-22 | 1992-09-23 | PECHINEY RECHERCHE (Groupement d'Intérêt Economique géré par l'ordonnance du 23 Septembre 1967) | Material for passive electronic components |
US6448510B1 (en) * | 1997-05-20 | 2002-09-10 | Micro Components Ltd. | Substrate for electronic packaging, pin jig fixture |
EP0936849A1 (en) * | 1998-02-17 | 1999-08-18 | Pressac Interconnect Limited | Printed circuit assembly and method of making the same |
US6670704B1 (en) | 1998-11-25 | 2003-12-30 | Micro Components Ltd. | Device for electronic packaging, pin jig fixture |
EP1587348A1 (en) * | 2004-03-30 | 2005-10-19 | Feng Chia University | Conductive base board |
WO2007091976A1 (en) * | 2006-02-10 | 2007-08-16 | Opulent Electronics International Pte Ltd | Anodised aluminium, dielectric, and method |
WO2007133074A1 (en) * | 2006-05-12 | 2007-11-22 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | A process for preparing a heatsink system and heatsink system obtainable by said process |
US8296942B2 (en) | 2006-05-12 | 2012-10-30 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | Process for preparing a heatsink system and heatsink system obtainable by said process |
WO2008021269A2 (en) * | 2006-08-11 | 2008-02-21 | E. I. Du Pont De Nemours And Company | Device chip carriers, modules, and methods of forming thereof |
WO2008021269A3 (en) * | 2006-08-11 | 2008-04-10 | Du Pont | Device chip carriers, modules, and methods of forming thereof |
US8710523B2 (en) | 2006-08-11 | 2014-04-29 | E I Du Pont De Nemours And Company | Device chip carriers, modules, and methods of forming thereof |
Also Published As
Publication number | Publication date |
---|---|
GB8708457D0 (en) | 1987-05-13 |
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