JPS63162848A - Production of ceramic coated copper foil - Google Patents

Abstract

PURPOSE:To improve the adhesion of a ceramic coat to electrolytic copper foil, by electrodepositing fine particles on the roughened surface of the foil to make the surface finely uneven and by plasma-spraying ceramics on the uneven surface. CONSTITUTION:The surface of electrolytic copper foil is roughened and fine particles of copper, a copper compd. or a copper alloy are electrodeposited on the roughened surface to make the surface finely uneven. A ceramic layer is then formed on the uneven surface by plasma-spraying ceramics such as alumina. Thus, ceramic coated copper foil whose ceramic coat has superior adhesion to the base copper foil is obtd. The ceramic coated copper foil can be used as a material for a printed circuit board or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for manufacturing a ceramic-coated copper foil that has the layered properties of ceramic.

(Prior Art) In recent years, with the advent of new ceramics, ceramics have come to be actively used as functional materials, including structural materials, electronic materials, and the like. Under these circumstances, ceramic coating is a useful technique for modifying the surface of metal, plastic, etc. by providing a ceramic layer on the surface of metal, plastic, etc. Ceramic coating improves the abrasion resistance and surface li! Every time,
Features such as heat resistance, electrical insulation, and heat insulation can be easily imparted to the base material, and the disadvantages of ceramic alone, such as brittleness and poor workability, can be compensated for.

Ceramic coating methods include CVD method and PV
There are many methods such as D method, sol-gel method, thermal spray method, etc.
ZorL! Il! Among these methods, thermal spraying has a faster film formation rate than other methods, and there are fewer restrictions on the shape and area of the substrate to be coated, so it can be easily mass-produced. Since the temperature of the material to be thermally sprayed does not need to be exposed to a high temperature of several hundred degrees Celsius as in the case of CVD, PVD, etc., it has the advantage that it can be used as a solvent even for materials with poor heat resistance.

Therefore, it is considered to form a ceramic layer on the gold m4 body using molten g4fF: to form a composite. Among these materials, a material in which a ceramic layer is formed by thermally spraying ceramic on copper foil is very useful for surface modification of printed MA boards. That is, by integrating such ceramic-coated copper foil with conventional organic substrates such as glass/epoxy, paper/phenol, etc. It is possible to improve the basic characteristics such as low thermal conductivity, heat resistance, and coefficient of thermal expansion. On the other hand, if ceramic-coated copper foil is integrated with a metal layer such as an aluminum plate, the thermal conductivity of conventional metal base or metal core base machines is low because the insulating layer is made of resin, but if ceramic-coated copper foil is used Immediately below the copper foil that forms the circuit is a ceramic layer at 7'L that has high thermal conductivity and heat resistance, so the thermal conductivity can be further improved.

(Problems to be Solved by the Invention) However, when ceramic is applied to copper foil using the conventional method, the adhesion between the copper foil and the ceramic layer is very low and cannot be put to practical use.

The first reason for this is that in ceramic thermal spraying, there is a large difference in adhesion depending on the type of material to be thermally sprayed, and among these, it is said that the adhesion of steel or steel alloy materials is particularly poor. However, the reason for this has not yet been clearly determined.

Second, surface roughening treatment by blast treatment may be difficult. In the general double-spraying method, a blast treatment is performed to roughen the sprayed surface of the material to be sprayed and improve the adhesion of the spraying due to the anchor effect. In addition to the effect of forming an uneven surface on the sprayed surface, this blast treatment also has the effect of forming an uneven surface on the sprayed surface.
, j, and has the effect of forming and activating a new surface. This blast treatment is a method of roughening the treated surface by blowing a hard material such as alumina or glass beads onto the treated surface at high speed using air pressure. However, in the case of copper, M is very soft, so the uneven surface initially formed during blasting is easily flattened by the subsequent collision with the plastic material, forming a fine uneven surface that produces an anchor effect. It's hard. Furthermore, in the case of 4 pieces like @ foil, defects such as dents and breaks are likely to occur due to the high-speed collision of the plastic material. It is difficult to form.

To determine these causes, when ceramic is completely sprayed onto copper foil using conventional technology, the adhesion between the ceramic and copper foil is extremely low, and in severe cases, the ceramic powder does not drip onto the copper foil during thermal spraying. Even if it is flicked or piled up, it easily cracks and peels (I cannot find anything that can withstand practical use).

The present invention aims to improve the above-mentioned drawbacks and provide a method for obtaining a ceramic coated copper foil by a melting process, which improves the adhesion between the ceramic and the copper foil.

(Means for Solving the Problems) In other words, the present invention can be used as copper foil in the decoration of ceramic foil! Using decopper foil, further copper, f is applied to the roughened surface.
The main feature is that fine particles of a compound or alloy such as copper or copper are electrodeposited to form fine irregularities, and a ceramic layer is formed by applying ceramic to the fine irregular surface.

The reason for using electrolytic copper foil as the copper foil in the present invention is that a roughened surface can be easily obtained. Copper foil is roughly divided into two types depending on its manufacturability: electrolytic copper foil and rolled @ foil.

Electrolytic copper foil is produced by dissolving copper raw material in a sulfuric acid aqueous solution and ionizing it, then continuously subjecting the copper to T* through an electrolysis reaction using a rotating drum as a cathode, and continuously peeling it off from the drum and rolling it onto a winding roll. It is obtained by winding it up.

The surface peeled off from the drum becomes a smooth surface because it transfers the drum surface, but the opposite surface becomes a roughened surface just like the 'x-attached surface. That is, a roughened surface can be obtained in one step.

Rolled copper foil is produced by melting and solidifying electrical steel to form an ingot, which is then rolled using a rolling mill to form a foil. Are both sides of the copper foil flat as is? Since it becomes an l# surface, further roughening is required to obtain a roughened surface.

Next, on the roughened surface of the NRS electrolytic copper foil obtained in this way, fine particles of steel, or a compound or alloy containing steel are further electrodeposited to form fine irregularities. This is to obtain an anchor effect during thermal spraying by forming the entire surface. The roughened surface obtained in the first step of decoppering foil has insufficient unevenness, has little anchoring effect, and does not provide sufficient adhesion between the ceramic and copper foil. Therefore, it is necessary to make the irregularities even finer by attaching finer particles to this roughened surface.

The reason why the electrodeposition method is commonly used as a method for forming fine irregularities is to simplify the process. That is, following the first step of manufacturing electrolytic foil, electrodeposition of fine particles onto the roughened surface can be performed continuously as a second step. Further, by electrodeposition, it is possible to obtain a product with high adhesion between the copper foil and the fine particles. As fine particles formed by electrodeposition, those containing steel such as steel, oxidized steel, sub-oxidized steel, steel-nickel attached, steel-zinc attached, copper-chromium alloy, etc. are preferable from the viewpoint of adhesion to cavities. It is.

Ceramic spraying methods include gas spraying, plasma spraying, low-pressure plasma spraying, and water plasma spraying, and the ceramic materials to be sprayed include alumina, titania, zirconia, silica, and spinel. , mullite, barium titanate, and the like can all be used.

Note that the thickness of the copper foil is preferably 10 μm or more and 250 μm or less. If the thickness of the copper foil is less than 10 μm, the copper foil is likely to be deformed or broken due to heat absorption during thermal spraying. Moreover, if the thickness exceeds 250 μm, the foil is too thick and cannot be etched in the etching process, for example, as a printed wiring layer, which greatly limits its uses.

(Function) In order to obtain a ceramic-coated copper foil by pricking a ceramic foil with a ceramic coating, electrolytic copper foil is used as the copper foil, and further fine particles are electrodeposited on the roughened surface of the foil to obtain a ceramic-coated copper foil. Create unevenness,
By thermally spraying ceramic onto that surface, a ceramic-coated copper foil can be obtained which has excellent adhesion that could not be obtained with the prior art.

In conventional methods, when spraying ceramics,
# The surface to be thermally sprayed of the material is treated with a plasto to create unevenness, but in the case of copper foil, the copper foil is soft,
Moreover, since it is thin, it is easily deformed, and a sufficient blast treatment cannot be performed, making it impossible to form irregularities that would improve adhesion. Furthermore, since copper is the material with the poorest adhesion in ceramic baths, it is impossible to obtain a ceramic-coated copper foil with adhesion that can withstand practical use.

However, as in the present invention, by electrodepositing fine particles made of steel on the roughened surface of copper foil, it is possible to obtain a finely uneven surface that cannot be obtained by plasting. When ceramic is thermally sprayed onto such a finely uneven surface, a so-called anchor effect is obtained by the ceramic spraying material penetrating into the finely uneven surface. B can't be obtained with conventional plastic processing due to the rL, which is large! I!
! Adhesiveness is obtained.

In addition, by using the thermal spraying method as a means of forming ceramic/I#, it is possible to coat a large area of copper foil with ceramic.
can be mass-produced at a high deposition rate.

The present invention will be described below with examples. ! -Explain.

(Example) The roughened surface ([the back side of the peeled surface from the rotating drum which becomes the cathode during the production of the decopper foil] of the ``IIL counterfeit copper foil with a thickness of 65 μnl obtained by the electrolytic method'' was coated with ``v17!r''). Fine particles of copper oxide (particle size: 5 μm to 2 μm) were deposited to obtain a copper foil having a finely uneven surface.

Alumina was sprayed onto the thus obtained surface of the foil with 9 fine irregularities using a plasma spraying method to a thickness of approximately 10 mm.
The adhesion between the alumina of the alumina aami obtained in this way and the J11 foil was a tensile sag of 1.2 toughness/d.

Note that FIG. 1 is a schematic cross-sectional view of an alumina-coated copper foil showing an example of the present invention.

(Comparative Example 1) An alumina layer was formed by coating an alumina-coated copper foil on the magnetized surface of an electrolytic copper foil by a plasma m-side method without depositing fine particles as it was on the magnetized surface of an electrolytic copper foil. At this time, the tensile strength of the alumina and copper foil was cL2kg/w.

(Comparative Example 2) The roughened surface of the copper foil used in Comparative Example 1 was subjected to a blast treatment using an alumina grid, and then alumina was applied by plasma spraying. At this time, the adhesion between the alumina and the copper foil was 0.25 kg/mII+ in terms of tensile strength, and almost no effect of the blast treatment was observed.

(Effects of the Invention λ According to the present invention, in order to obtain a ceramic coating, fine grains are electrodeposited on the roughened surface of the electrolytic copper foil to form fine irregularities, and then the surface is subjected to a blast treatment. The method of thermal spraying ceramic without any
Ceramic coated steel W3T with excellent adhesion between ceramic and copper foil? Obtainable.

Such ceramic-coated copper foil is extremely useful in a variety of fields, including materials for printed guns.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an alumina-coated copper foil showing an example of the present invention. Code explanation 1 Electrolytic copper w321! Fine particle layer of chemical steel 3 Alumina Numagi layer 1 □- Representative patent attorney Gun Hirose・1.゛)V'''+-,=

Claims (1)

[Claims] 1. Ceramic in which fine particles of copper or a compound or alloy containing copper are electrodeposited on the roughened surface of electrolytic copper foil to form fine irregularities, and ceramic is sprayed onto the fine roughened surface to form a ceramic layer. A method for producing coated copper foil.