JPS5821439B2 - Ceramic splint body warmer Oyobi Sonoseizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a printed circuit board in which an electrically conductive metal thin film with strong adhesive strength is formed on a ceramic substrate.

The main objective is to use a new method to form a metal thin film with excellent crystallinity and adhesion on a ceramic substrate, thereby making it possible to increase circuit density and improve reliability. It is an object of the present invention to provide a simple method for manufacturing a printed circuit board with a shortened process.

Conventionally, ceramic splint circuit boards have been produced by forming a thin film on a ceramic substrate using a physical method such as vacuum deposition or sputtering, or by printing a circuit on the substrate using conductive paint.

However, with conventional physical methods, sufficient adhesion strength could not be obtained, and therefore highly reliable printed circuit boards could not be obtained, excellent film quality with good crystallinity could not be obtained, and precious metals could not be obtained. However, when using this method, there were disadvantages such as low yield and high product cost.

Further, when using conductive paint, there are drawbacks such as high cost due to the need for post-processes such as baking, and difficulty in creating high-density circuits.

In order to resolve these drawbacks of conventional ceramic printed circuit boards, the inventors of the present invention have carried out intensive research and have developed a method that provides strong adhesion strength to ceramic substrates by applying special physical means to the ceramic substrate. The inventors discovered a method of manufacturing a ceramic splint circuit board in which a circuit of an electrically conductive metal thin film was directly formed, and after conducting various researches, the present invention was completed.

Next, a detailed description of the invention An example will be explained.

An example of the apparatus used in the present invention is shown in FIGS. 1 and 2.

The inside of the deposition chamber 3 is changed from I
A vacuum of XIO-7 Torr is maintained, and a vacuum of 0.0 Torr is maintained between the red-hot crucible heater 8 and the crucible 12 containing the metal to be deposited. A DC voltage of IKV to IOKV was applied with the crucible side set as positive, a current of 0.1 to 10A was applied, and a current of 200 to 10A was applied.
Heat to 2500°C.

In this case, the method of heating the crucible may be, in addition to the electron impact method, resistance heating or induction heating, or a heating method that is a combination of these methods.

The crucible needs to be heated in a trench to a temperature that sufficiently evaporates the metal to be evaporated, and depending on the type of metal to be evaporated, the temperature may be below 1500℃, and the electric power consumed between the crucible and the crucible heater must be kept at this temperature. It must be sufficient to understand.

When the crucible temperature rises and the metal vapor pressure inside the crucible increases, the metal vapor is injected in one direction from the small hole at the top of the crucible.

The injected metal vapor is rapidly cooled by the pressure difference between the inside and outside of the crucible, loses kinetic energy in directions other than the direction of injection, and becomes kusisters (clumps of atoms) due to van der Waals forces.

The shape of the crucible may be cylindrical, pipe-shaped, box-shaped, etc. For example, in the case of a cylindrical shape, the diameter of the crucible small hole is 1% to 30% of the crucible inner diameter, but more preferably 5 to 20%. %.

This means that if the diameter of the small hole is smaller than the inner diameter of the crucible,
This is because the pressure difference between the inside and outside of the crucible becomes smaller, the rate of cluster generation becomes smaller, and when the diameter of the small hole becomes smaller than the inner diameter of the crucible, the deposition rate becomes smaller.

Next, the generated clusters are ionized by collision with electrons generated by applying a DC voltage between the red-hot ionization heater 10 and the ionization anode 9 with the ionization anode being positive, and the clusters are ionized by collision with electrons generated by applying a DC voltage between the red-hot ionization heater 10 and the ionization anode 9. 1
It is accelerated by the voltage applied between the ionizing anode and the ionizing anode, and is deposited on the ceramic T of the substrate.

In this case, the DC voltage applied to the ionization heater and the ionization anode is 10 to 100 OV, and the electron current in the ionization tank is, for example, I
The current may be 10 to 1000 mA with respect to the metal vapor pressure of orr, but 10 to 300 mA is preferable for ceramic substrates, and if the metal vapor pressure becomes higher, this current needs to be increased.

Also, the voltage applied between the substrate electrode and the extraction electrode is 1
0 to 100 OOV, preferably 100 to 5000 V for ceramic substrates.

When a metal thin film is deposited on a ceramic substrate in this way, partial deposition is performed by masking the surface of the substrate, and a printed circuit board with a desired pattern can be directly obtained.

Examples of masking methods used here include a method in which a thin metal plate with a pattern opposite to that of the desired circuit, obtained by removing the necessary circuit portion by etching, is closely attached to the vapor-deposited surface of the substrate; There is a method in which a reverse pattern of the pattern is printed in ink or a photograph, and after the deposition is completed, the deposited metal applied on the ink or photographic print is removed by a mechanical or chemical method.

The ceramic substrate moves on a guide chain from the supply section 1 to the recovery section 2, or during vapor deposition, it rests on a mask 14, which is a fixture at the top of the vapor deposition chamber, and is held down by a presser 5 to ensure close contact with the mask. Try to keep it.

In this case, it is of course possible to deposit the circuit while moving the substrate and mask at the same speed.

; In the above method, the degree of vacuum in the deposition chamber is set to 1×10'T.
The reason for increasing I x 10-7 Torr from orr is to obtain a metal film with good crystallinity and good film quality.

In addition, by ejecting metal vapor from the small holes in the upper part of the crucible, metal clusters are generated, and at the same time, the spatial distribution of the vaporized vapor and clusters is narrowed to reduce the rate at which they reach the metal substrate.

The reason why the injected metal vapor and metal clusters are ionized and accelerated is as follows:
This is to provide strong adhesion strength by applying energy from 0 eV to several thousand eV to embed metal atoms and two stars in the substrate surface.

Further, in order to obtain strong adhesion strength and good film quality, it is preferable to heat the ceramic substrate to 100 to 700°C.

The metal substance used to generate the metal vapor here may be any metal as long as it has electrical conductivity and a temperature at which the vapor pressure of 1X10-'' Torr is 2500° C. or less.

Examples include kl, Cu, Pb, Cr, Ni, Fe, Au, etc., but are not particularly limited to these.

Metals with too high evaporation temperature are not preferred because they will seriously damage the crucible.

What kind of ceramics is used as a substrate? Any RR ceramics will suffice.

Examples include steatite, forsterite, alumina, feldspar, beryllia, crystallized glass, and ordinary glass.

There is no particular limit to the thickness of these substrates, and for the present invention, ceramic substrates having a thickness of approximately 0.1 mm to 10 mm are preferred.

The thickness of the metal film can be formed to any thickness depending on the application, and the thickness may be determined depending on the application, or a thickness of several amps to several tens of microns is generally suitable for the purpose of the present invention.

The printed circuit board produced in this manner can be processed by conventional processing methods applied to printed circuit boards, such as wet plating, and can be used in a wide range of applications such as electrical equipment and electronic equipment.

The ceramic printed circuit board made according to the present invention has many advantages over conventional ceramic printed circuit boards.

That is, (1) a pinhole-free, homogeneous electrically conductive thin film with strong adhesion strength is provided on the ceramic substrate.

The adhesion strength is good at 60 kg/CrIL2 or more.

(2) Compared to conventional ceramic printed circuit boards,
Because the metal film has a high density and strong adhesion, it is suitable for creating fine circuits, and it is possible to increase the density of circuits.

(3) Since the film is formed by applying high kinetic energy to the deposited substance in a high vacuum, the film has good crystallinity and therefore good electrical conductivity.

This is advantageous in circuit design.

(4) The spatial distribution of metal vapor is narrowed by ejecting the metal vapor from the small holes in the upper part of the crucible, so the yield of vapor-deposited metal is extremely high.

This is extremely advantageous when noble metals are used as the vapor deposition material.

As described above, the ceramic splint circuit board produced according to the present invention has many excellent features, and the manufacturing method thereof is simple, highly accurate, pollution-free, and resource-saving, making it extremely effective industrially. This is a great method.

Example 1 An alumina plate having a thickness of 1.0 mm was used as a substrate material, and gold was deposited using the apparatus shown in FIGS. 1 and 2.

The crucible has an inner diameter of 30mm, a height of 30mm, and a 3mm point in the center.
It has one hole and is made of carbon.

The deposition conditions were as shown in Table 1, and gold was deposited to a thickness of 1 μm through a stainless steel mask to obtain a circuit board with a circuit in the desired pattern.

The printed circuit board created in this way has a homogeneous gold film circuit with no pinholes, and has an adhesion strength of 60 kg.
/cr/L2 or more.

Furthermore, the minimum circuit width of this circuit board was 20 microns.

It also had excellent solder heat resistance and wear resistance, making it a fully usable printed circuit board.

Example 2 1 A 2μ thick copper film was formed on a 20mm thick steatite porcelain substrate under the same conditions as in Example 1.

In this case as well, a homogeneous copper film without pinholes was obtained, and the adhesion strength was 60 kg/CIrL2 or more.

Although the minimum mesh width was 20μ, the printed circuit board had good DC and AC low voltage and high voltage insulation properties, soldering heat resistance, etc. between the circuits, and was sufficiently durable for practical use.

Example 3 Under the same conditions as Example 1, 1.0 dragon thickness IJ IJ
2 μm of copper is deposited on a ceramic substrate to form a printed circuit.
1 μm of gold was plated thereon by a wet method.

The adhesion strength after gold plating was 50 kg/CIIL2 or more, the solder heat resistance was also good, and it could be used as a high-density small circuit board.

[Brief explanation of drawings]

FIG. 1 shows an overview of the apparatus used in the present invention, and FIG. 2 shows an overview of the vapor deposition chamber. In the figure, 1 is a substrate supply section, 2 is a substrate recovery section, 3 is a deposition chamber, and 4
1 is a cluster ion beam generation unit, 5 is a presser that also serves as a substrate electrode and a substrate heating device, 6 is a guide chain, 7 is a ceramic substrate, 8 is a crucible heater, 9 is an ionization anode, 10 is an ion heater, and 11 is a drawer. electrode, 12
13 indicates a crucible, 13 a metal used for vapor deposition, and 14 a mask. In addition, Al-Al, ', A2-A2', B1-B in Fig. 2
1' and B2-B2' indicate that they are connected.

Claims (1)

[Claims] 1 In an evacuated room, heat a metal steam generation furnace with one or several sets of small holes, generate metal clusters (clump-like atomic groups) from the small holes, and bring this metal 2 star into the room. Ceramics that are ionized by being bombarded with electrons generated from a provided electron generator, and the generated metal cluster ions are accelerated in an atmosphere containing non-ionized metal clusters to attach a continuously moving metal film. A method of manufacturing ceramic printed circuit boards by irradiating the board through a mask to create printed circuits on the board.