JP2007119871A - Method for depositing metal film, and method for depositing electrode pattern by means of metal film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for depositing a metal film which is inexpensive compared with the deposition of a metal film by the conventional vacuum deposition, and can solve the problem that metal powder does not stuck onto a substrate due to its oxiidadation when the metal powder is sprayed on the substrate to deposit the metal film. <P>SOLUTION: The inside of a working chamber is made into a gaseous nitrogen atmosphere, and a mixed fluid of gaseous nitrogen and metal powder is sprayed on a working substrate in the gaseous nitrogen atmosphere, thus a metal film can be deposited on the surface of the substrate without oxidizing the metal powder, and a wiring pattern by the metal can easily and stably be formed on the working substrate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a method for forming a uniform metal film on an inorganic substrate stably and easily, and further relates to a method for forming a uniform electrode pattern using the metal film.

Conventionally, as a method of generally forming a metal film on a substrate surface, a method of forming a metal film by vacuum deposition has been generally performed.

As a method other than vacuum deposition, a method of forming a metal film by injecting low melting point metal powder into the air using a high-pressure gas such as high-pressure air and using a general sandblasting device has been proposed. .

JP 2001-94235 A JP 2000-265286 A

In the conventional method of forming a metal film by vacuum deposition, it takes a long time to achieve a high vacuum, and if the base material is large, a large vacuum device is required, which increases the price of the device and increases the vacuum device. There is a problem that it takes a long time to make a higher vacuum when the size of the substrate becomes larger.

In addition, in the method of injecting metal powder into the air with high-pressure gas, the metal on the surface of the metal powder melts and adheres to the base material due to the impact heat generated when the metal powder collides with the base material. Is limited to metals with a low melting point such as tin, zinc or indium of 500 ° C. or less. Even when a low melting point metal is used, the surface of the metal powder is oxidized during repeated injection and collision to the substrate surface. There was a problem of not sticking.

In particular, a high melting point metal having a melting point of 600 ° C. or higher has a higher temperature, and an oxide film can be easily formed. In a conventional atmosphere where a large amount of oxygen exists in air, the metal film cannot be formed.

In addition, even if a gas such as nitrogen gas is used as an air source for injecting metal powder, a general suction type sandblasting device sucks and injects the abrasive, so that outside air is also taken in with the abrasive. Therefore, injection with only nitrogen gas is difficult, and oxygen in the atmosphere is also taken in when metal powder is injected from the nozzle, so that the metal is oxidized and a metal film cannot be formed.

In general, copper, aluminum, or silver having a low electric resistance is used as a metal used for forming an electrode pattern for electric wiring or the like, and any metal having a low electric resistance has a high melting point of 600 ° C. or higher. Therefore, there has been a demand for a method by which a high melting point metal film can be easily formed on a substrate without being oxidized.

As a means for solving the above-mentioned problems, the processing chamber is provided with a nitrogen gas atmosphere by feeding nitrogen gas while sucking the air in the processing chamber by the negative pressure of the blower, and the average particle size is 30 μm. The inside of the tank into which the following metal powder was introduced was pressurized with nitrogen gas at a pressure of 0.05 MPa or more, and a certain amount of the metal powder was transferred from the tank pressurized with the nitrogen gas through the metal powder supply device. In addition, it is supplied to a metal powder injection nozzle through a metal powder supply pipe, and by spraying a mixed fluid of the metal powder and nitrogen gas from the metal powder injection nozzle, an inorganic such as metal, ceramic, glass, silicon wafer, compound semiconductor, crystal, etc. A metal film was formed on the substrate surface.

Occurs when the processing chamber has a nitrogen gas atmosphere and a mixed fluid of metal powder and nitrogen gas pressurized with nitrogen gas is blown into the nitrogen gas atmosphere, causing oxygen to become extremely dilute and colliding with the processing substrate. It was possible to prevent the metal powder from being oxidized by the applied heat, and to stably form a metal film on the surface of an inorganic base material such as metal, ceramic, glass, silicon wafer, compound semiconductor, or crystal.

Further, it becomes possible to form a metal film by spraying a metal powder having a melting point of 600 ° C. or higher onto the substrate surface, which could not be performed in air containing a high concentration of oxygen, and has a high conductivity having a melting point of 600 ° C. or higher. It has become possible to form a wiring pattern on the surface of a base material such as ceramic, glass, silicon wafer, compound semiconductor, crystal, or the like, using metals such as aluminum, copper, and silver at low cost.

The best mode for carrying out the metal film forming method and the electrode pattern forming method using the metal film of the present invention will be described below with reference to the drawings.

FIG. 3 shows an example of forming a wiring pattern by using a photosensitive dry film as a resist to form a resist pattern on a substrate and then spraying metal powder with nitrogen gas.

A liquid photosensitive resist other than the photosensitive dry film may be used, or a resist pattern may be formed on the substrate by screen printing using a resist ink.

At (3-1) in FIG. 3, a photosensitive dry film 41 is laminated on the processed substrate 7 using a laminator for dry film.

A mask pattern 40 such as a glass mask or a film mask is placed on the photosensitive dry film 41 attached to the processed substrate 7 in (3-2), and ultraviolet exposure is performed by an exposure apparatus.

The photosensitive dry film 41 exposed in (3-3) is developed by spraying a developer 44 from the developing nozzle 43 with a dry film developing machine.

In (3-4), a mixed fluid 6 of nitrogen gas and metal powder is sprayed in a nitrogen gas atmosphere to form the metal film 50 on the processed substrate 40.

An apparatus as shown in FIGS. 1 and 2 is used as an apparatus for spraying metal powder.
1 and 2, the metal powder pressurization valve 24 is closed after the metal powder pressurization tank 22 is filled with the metal powder 5.

The dust collector 35 is connected to the processing chamber 30 via the cyclone 32, and nitrogen gas is introduced into the nitrogen gas introduction portion 3 for feeding metal powder while sucking air in the processing chamber by the negative pressure of the blower of the dust collector 35. The gas is supplied from the metal powder supply pipe (metal powder supply hose 28) into the processing chamber 30 from the metal powder injection nozzle 20 to bring the processing chamber into a nitrogen gas atmosphere, the oxygen concentration in the processing chamber is lowered, and the nitrogen gas is substantially reduced. It becomes an atmosphere.

Instead of supplying nitrogen gas from the metal powder injection nozzle 20, nitrogen gas may be directly introduced into the processing chamber while sucking air in the processing chamber by the negative pressure of the blower of the dust collector.

After supplying nitrogen gas into the processing chamber 30, nitrogen gas is introduced from the tank pressurizing nitrogen gas introducing unit 2, and the metal powder pressurizing tank 22 is pressurized with nitrogen gas, and a certain amount of metal is supplied from the metal powder quantitative supply device 10. A mixed fluid of powder and nitrogen gas is supplied to a metal powder supply pipe (metal powder supply hose) 28, and a mixed fluid 6 of metal powder and nitrogen gas is sprayed from a metal powder spray nozzle 20 and sprayed onto the processed substrate 7.

The metal powder injection nozzle 20 swings left and right in the processing chamber and moves the processed substrate 7 back and forth, thereby spraying a mixed fluid 6 of metal powder and nitrogen gas over the entire surface of the processed substrate 7.

The sprayed metal powder 5 is collected by the cyclone 32 through the cyclone conduit 27 by the negative pressure of the blower of the dust collector from the hopper 33 in the processing chamber, and enters the metal powder collection tank 29.

The metal powder 5 is supplied from the metal powder collection tank 29 into the metal powder pressurization tank 22 by opening the metal powder pressurization valve 24 after completion of the injection from the metal powder injection nozzle 20, and again with the nitrogen gas from the metal powder injection nozzle 20. A mixed fluid of metal powder is injected.

Two metal powder pressure tanks 24 are provided, and the metal powder 5 continuously collected by the cyclone 32 by opening the valve alternately is injected into the metal powder pressure tank 22 even during the injection from the metal powder injection nozzle 20. 5 may be supplied.

The pressure of the nitrogen gas for injecting the metal powder 5 is 0.05 MPa or more and 0.3 MPa or less, preferably 0.1 MPa or more and 0.3 MPa or less.

If the processing pressure is less than 0.05 MPa, the thermal energy generated by colliding with the substrate will be small, and if it is greater than 0.3 MPa, the generation of thermal energy will increase and it will be easily oxidized by the trace amount of oxygen remaining in the processing chamber. There is a tendency that the adhesion of the metal film becomes worse with time processing.

During processing, it is desirable to introduce nitrogen gas into the processing chamber so that the oxygen concentration is 0%. However, even if a small amount of oxygen remains, if the processing pressure is 0.3 MPa or less, the metal powder is oxidized. It is possible to form a metal film by spraying metal powder while suppressing.

The oxygen concentration in the processing chamber in a nitrogen gas atmosphere is 5% or less, preferably 2% or less.

In the case of forming an electrode pattern, the average particle size of the metal powder to be ejected is 30 μm or less, preferably 20 μm or less.
When the metal particle size is increased, the metal particles are clogged between the patterns and cannot be processed.

In the case of forming an electrode pattern made of metal, it is desirable to use a metal powder having an electrical conductivity of above, and a metal powder such as aluminum, copper, or silver having a melting point of 600 ° C. or higher and 1200 ° C. or lower is used.

When a metal powder having a high melting point higher than 1200 ° C. was blown with nitrogen gas in a nitrogen gas atmosphere, a metal film could not be formed.

Generally, the metal used as an electrode pattern has a melting point of 600 ° C. or higher, and a metal lower than 600 ° C. has low metal hardness and is not practical with a film thickness of several microns attached when a metal film is sprayed. .

In the method of forming a metal film by spraying a mixed fluid of nitrogen gas and metal powder in the nitrogen gas atmosphere of the present invention, since only a film thickness of several microns can be formed, a metal formed by spraying is required to further increase the film thickness. The film thickness is increased by electroless plating based on the film.

Hereinafter, the present invention will be described in detail with reference to examples.

BF45Z manufactured by Tokyo Ohka Kogyo Co., Ltd., which is a photosensitive dry film for sandblasting, is laminated on an alumina substrate at a laminating temperature of 70 ° C. using a dry film laminator ELM-350 manufactured by Elfotec.

It is placed on the photosensitive dry film 41 laminated with a film mask having a line pattern of 200 μm width, and is brought into close contact with a vacuum, and is exposed with an exposure machine EEX350 manufactured by Elfotec Co., Ltd. at an exposure amount of 200 mJ.

The exposed photosensitive dry film is developed using a developing machine manufactured by Elfotec.

The temperature of the developer was 30 ° C., an injection pressure of 0.25 MPa, and an aqueous sodium carbonate solution having a developer concentration of 0.3% was used.

In advance, 5 kg of copper powder having an average particle size of about 10 μm was charged into the metal powder pressure tank, and then the metal powder pressure valve was closed.

Turn on the dust collector, introduce nitrogen gas from the nitrogen gas introduction part for metal powder pumping while making the processing chamber negative pressure by the blower of the dust collector, and only nitrogen gas from the metal powder injection nozzle at a pressure of 0.1 MPa about 3 The process chamber was sprayed for minutes to create a nitrogen gas atmosphere.

The nozzle is swung left and right at a speed of 5 m / min, and the conveyor is moved forward at a speed of 20 mm / min. Pressurize with nitrogen gas, supply copper powder of 170g / min and nitrogen gas of pressure 0.15Mpa from the metal powder quantitative supply device to the metal powder supply pipe (metal powder supply hose) from the metal powder injection nozzle Copper powder was sprayed on the entire surface of the alumina substrate at a pressure of 0.15 MPa.

The alumina substrate onto which the copper powder was sprayed was taken out of the processing chamber, put on a 1% monoethanolamine aqueous solution, the dry film on the surface of the alumina substrate was peeled off, and a wiring pattern with a copper film having a thickness of about 2 μm was formed.

As industrial applicability of the present invention, a metal pattern is sprayed on a substrate such as a ceramic in a nitrogen gas atmosphere at atmospheric pressure, and a wiring pattern can be formed on the substrate such as a heat-resistant ceramic stably. It becomes possible to form.

Side view of a device for jetting metal powder Cross-sectional view of mechanism for injecting metal powder Process diagram of electrode pattern formation with metal

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High pressure gas 2 Nitrogen gas introduction part for tank pressurization 3 Nitrogen gas introduction part for metal powder pressure feeding 5 Metal powder 6 Mixed fluid of nitrogen gas and metal powder 7 Processed substrate 10 Metal powder fixed supply device 16 Metal powder supply roller 17 Metal powder take-out Unit 20 Metal powder injection nozzle 21 Metal powder injection tank 22 Metal powder pressurization tank 23 Metal powder injection nozzle chip 24 Metal powder pressurization valve 26 Nitrogen gas conduit 27 for tank pressurization Cyclone conduit 28 Metal powder supply pipe (metal powder supply hose)
29 Metal powder collection tank 30 Processing chamber 31 Metal powder injection device body 32 Classifier (Cyclone)
33 Hopper 34 Main body conduit 35 Dust collector 36 Vibrator 37 Dust collection conduit 38 Nozzle driving unit 39 Conveyor driving unit 40 Mask pattern 41 Photosensitive dry film 42 Laminating roll 43 Developing nozzle 44 Developer 45 Patterned photosensitive dry film 46 Stripping solution 47 Stripping liquid injection nozzle 50 Metal film

Claims (2)

The inside of a tank into which metal powder having an average particle diameter of 30 μm or less and a melting point of 1200 ° C. or less is introduced is pressurized with nitrogen gas at a pressure of 0.05 MPa or more, and a certain amount of the tank is pressurized from inside the tank pressurized with the nitrogen gas. The metal powder is supplied together with nitrogen gas to the metal powder injection nozzle through the metal powder supply pipe, and the mixed fluid of the metal powder and nitrogen gas is previously supplied from the metal powder injection nozzle to the air in the processing chamber at the negative pressure of the blower. Nitrogen gas is introduced into the processing chamber while inhaling air, and the metal or ceramic is sprayed onto an inorganic base material such as a metal, ceramic, glass, silicon wafer, compound semiconductor, crystal, or the like installed in the processing chamber in an almost nitrogen gas atmosphere state. Or a metal coating characterized by forming a metal film on the surface of an inorganic base material such as glass, silicon wafer, compound semiconductor or crystal. Film forming method. 2. The method of forming a metal film according to claim 1, wherein a resist ink is printed by screen printing on a ceramic, glass, silicon wafer, compound semiconductor, quartz or other processed substrate in advance, or a photosensitive dry film is formed. After forming a resist pattern with a photoresist such as a film, spray a mixed fluid of nitrogen gas and metal powder onto the processed substrate on which the resist pattern is formed, and after forming a metal film on the part other than the resist, the resist is peeled off to form an electrode pattern A method for forming an electrode pattern with a metal film on a processed substrate.

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