JPH0544045A - Method for controlling physical property of superfine particle film - Google Patents

Abstract

PURPOSE:To control or adjust physical properties, electric properties, chemical properties and other properties of a superfine particle film after the film is formed. CONSTITUTION:After a superfine particle film 2 is formed on a circuit substrate 1 by gas deposition method, this film 2 is heated by irradiation of laser light 15 so as to control the physical properties, electric properties, chemical properties, etc., of the film 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling physical properties of ultrafine particle film. More specifically, the present invention relates to a method for adjusting physical properties, electrical properties, chemical properties, etc. of an ultrafine particle film formed by a gas deposition method or the like.

[0002]

2. Description of the Related Art Ultrafine particles (for example, a particle size of about 0.1 μm or less) can be obtained by using a gas deposition method.
It has been reported that it is possible to form a film of (90th New Ceramics Society Research Committee material). Here, the gas deposition method means that the substance vapor generated in the ultrafine particle generation chamber is sent to the film formation chamber together with He gas through a carrier pipe.
Ultrafine particles agglomerated in the air are jetted from the nozzle of the transfer tube to the surface of the substrate in the film forming chamber, and the ultrafine particles are brought into close contact with the surface of the substrate to form an ultrafine particle film.

In a thick film method of firing a printing paste or a thin film method such as vacuum deposition or sputtering, the film quality that can be formed on a substrate is limited to a metal oxide or the like. On the other hand, in the method of forming the ultrafine particle film on the substrate by the gas deposition method, the film quality is not particularly limited, and the metal or the inorganic material,
An ultrafine particle film can be formed with an organic compound or the like.

Further, in a hybrid integrated circuit, a wiring board, etc., a thick film formed by screen-printing a conductive paste or the like and firing it is used. This thick film is formed by firing particles in the paste (particle size 10 μm
m or more) and particles are subjected to a solid phase reaction (for example, solid solution) to form a sintered body. On the other hand, since the ultrafine particle film has a large specific surface area (surface area / volume) and high activity, the solid-solid reaction starts with a small energy. This solid-solid reaction is also promoted by the dense particle matrix. As a result, the solid solution point becomes low between the ultrafine particles.

Further, in the thick film method and the thin film method, the substrate is required to have heat resistance because it is accompanied by baking and heating, and there is a limit to the substrate that can be used. On the other hand, in the method of forming the ultrafine particle film by the gas deposition method, there is no fear of damaging the substrate by heating. Moreover, the adhesion of the ultrafine particle film obtained by spraying ultrafine particles onto the substrate without heating the substrate is
This is equivalent to the adhesiveness when a vapor deposition film is formed on the surface of a substrate heated by vacuum vapor deposition.

Since the ultrafine particle film formed by the gas deposition method has the unique characteristics as described above, the ultrafine particle film is formed by using various materials, and the physical properties, electrical characteristics, and chemical properties of these materials are formed. It is conceivable to utilize the above for various purposes. For example, it may be used for resistors, capacitors, coils, wirings, functional materials for various sensors, and the like.

[0007]

However, in order to obtain desired characteristics and accuracy as an element, a sensor, etc., it is necessary to adjust the physical quantity, electric constant, etc. of the ultrafine particle film after forming the ultrafine particle film on the substrate. There is.

As a tuning method for the ultrafine particle film, a method of irradiating the ultrafine particle film with laser light to evaporate and remove the ultrafine particle film, which is conventionally used in a thin film method or the like, can be considered.

However, in such a method, a large amount of laser light is required, which consumes a large amount of energy, and the substrate may be damaged by the laser light, or heat may damage internal elements or the like. was there.

The present invention has been made in view of the drawbacks of the above conventional examples, and an object of the present invention is to obtain physical properties and electrical characteristics of an ultrafine particle film after forming the ultrafine particle film. It is to provide a method for easily controlling or adjusting chemical properties and other physical properties.

[0011]

The method for controlling the physical properties of an ultrafine particle film according to the present invention is characterized in that the physical properties of the ultrafine particle film are changed by irradiating the ultrafine particle film with light. Further, the ultrafine particle film can be formed by a gas deposition method.

[0012]

[Function] Since ultrafine particles have high light absorption ability, when the ultrafine particle film is irradiated with light, the ultrafine particles absorb light energy, and the ultrafine particles aggregate to increase the particle size or change the crystal grain boundaries. As a result, the physical properties, electrical properties, and chemical properties of the ultrafine particle film change. Therefore, the physical properties of the ultrafine particle film can be tuned by adjusting the irradiation time of light, the irradiation intensity, and the like.

Moreover, according to the method of the present invention, the physical properties of the ultrafine particle film can be adjusted without changing the shape (pattern) of the ultrafine particle film with a small energy.
Further, there is no fear of damaging the substrate by tuning the ultrafine particle film.

[0014]

EXAMPLE FIG. 1 is a schematic diagram showing a gas deposition apparatus 3 for forming an ultrafine particle film 2. This is an apparatus for directly drawing an ultrafine particle film using a gas deposition method, which has an ultrafine particle generation chamber 4 and a film forming chamber 5, and both chambers 4 and 5 are connected by a transfer pipe 6. ing. A vacuum pump 7 is provided in the ultrafine particle generation chamber 4 and the film formation chamber 5.
The pressure can be reduced by. A gas 9 such as He gas is supplied to the ultrafine particle generation chamber 4 via a flow rate adjusting valve 8. The ultrafine particle generation chamber 4 is provided with an evaporation tank 10 using a resistance heating method as a heat source, and a raw material 11 for forming the ultrafine particle film 2 is placed in the evaporation tank 10. On the other hand, a manipulator 12 for holding and moving the circuit board 1 is provided in the film forming chamber 5, and a nozzle 13 projects from the transfer pipe 6 toward the manipulator 12 side. Further, the laser light emitting end 14a of the optical fiber 14 is arranged in the vicinity of the nozzle 13 in the film forming chamber 5, and the laser light emitted from a laser oscillator (not shown) is emitted from the other end 14b of the optical fiber 14. 15 is made incident.

Then, the circuit board 1 is replaced with the manipulator 1
2, the film forming chamber 5 is decompressed by the vacuum pump 7, and the gas 9 is sent to the ultrafine particle generation chamber 4 to pressurize it while heating the raw material 11 in the evaporation tank 10 to evaporate the vaporized atoms. Are agglomerated into ultrafine particles and are sent to the film forming chamber 5 through the carrier pipe 6 together with the gas 9 such as He gas due to the pressure difference between the ultrafine particle generating chamber 4 and the film forming chamber 5, and the high speed circuit from the nozzle 13 It is jetted onto the surface of the substrate 1 to form an ultrafine particle film 2 as shown in FIG. At this time, the circuit board 1 is moved and scanned to obtain the ultrafine particle film 2 having a desired pattern.

The density of the ultrafine particle film 2 depends on the pressure difference between the ultrafine particle generating chamber 4 and the film forming chamber 5, the temperature of the circuit board 1, the temperature of the ultrafine particles, the jetting speed and the flow rate. The diameter, the crystal grain boundary, the crystal state, the degree of adhesion to the substrate, and the like can be changed, and the film thickness of the ultrafine particle film 2 can be changed depending on the moving speed of the circuit board 1, the injection amount of the ultrafine particles, and the like. The width of the ultrafine particle film 2 can be changed depending on the nozzle diameter. Therefore, the properties of the ultrafine particle film 2 can be changed by controlling these variables, and the characteristic values such as resistance and capacitance can be adjusted over a wide range.

According to the gas deposition method, there is no particular limitation on the material that can be used as the ultrafine particle film 2, and not only metal materials but also alloys, metal oxides, nitrides, carbides, organic compounds and the like can be used. You can

If an alloy of metals having the same boiling temperature is put in the evaporation tank, the ultrafine particle film 2 of the alloy can be formed. Furthermore, if two or more evaporation tanks are provided in the ultrafine particle generation chamber 5 and different metal materials are put therein, even if the boiling temperatures of both metal materials are different, it is possible to obtain an alloy such as a binary alloy (eutectic alloy) or the like. The fine particle film 2 can be formed. For example, according to such an alloy manufacturing method, it is possible to improve the ohmic contact property of the ultrafine particle film 2 and to add an appropriate dopant to the base metal. The circuit board 1 may be a ceramic substrate, an organic compound substrate such as an epoxy resin, or a metal substrate.

Further, after the ultrafine particle film 2 is formed on the circuit board 1, the surface of the ultrafine particle film 2 is irradiated with the laser light 15 emitted from the laser light emitting end 14a. Is a close order dimension,
The ultrafine particle film 2 has a high light absorption ability, and the ultrafine particles are laser light 1
Absorb 5 energy. As a result, FIG.
As shown in (b), the particles 16a to 16 in the ultrafine particle film are
c absorbs the energy of the laser beam 15 and is melted and recrystallized to grow into larger crystal grains 17, the crystal type is changed, or the crystal grain boundary is changed. The state and physical properties of 2a change, and the physical properties, electrical properties, and chemical properties of the ultrafine particle film 2 can be finely adjusted. Moreover, since the heat annealing can be efficiently performed by light, the circuit board 1 is not deteriorated by heat. Therefore, for example, it is possible to form the ultrafine particle film 2 in a state in which the adhesion to the circuit board 1 is good and then irradiate the laser beam 15 to adjust the physical properties of the surface layer portion 2c. Moreover, since the ultrafine particle film 2 easily absorbs light, it can be efficiently heated and annealed by the laser light, and there is no fear of applying thermal stress to the circuit board 1. The apparatus for irradiating the ultrafine particle film 2 with the laser beam 15 is separate from the apparatus for forming the ultrafine particle film 2 by the gas deposition method, and the bump forming step and the laser beam irradiating step may be separate steps. Good.

Further, as shown in FIG. 5, among the ultrafine particles, particles 18 having a diameter substantially the same as the wavelength of the laser light 15 absorb light energy, and particles 19 having a diameter larger than the wavelength of the laser light 15 are generated. Since light energy is transmitted, smaller particles are more likely to grow, and homogeneous grain growth is possible.

For example, FIG. 3 shows a capacitor 21 formed by forming an ultrafine particle film of a dielectric material on the circuit board 1. That is, the pair of comb-teeth electrodes 22 and 23 formed on the surface of the circuit board 1 are made to face each other so as to be meshed with each other, and the dielectric 24 is superposed between the comb-teeth electrodes 22 and 23 by a gas deposition method. A fine particle film is formed. Capacitor 2 having such a plane structure
When the laser light 15 is irradiated to the dielectric 24 of No. 1
Since the surface layer of No. 4 deteriorates and the dielectric constant changes, the capacitance of the capacitor 21 can be adjusted.

In the above example, the case where the capacitor is constructed by utilizing the dielectric constant of the ultrafine particle film and the dielectric constant is changed by irradiating the laser beam to adjust the capacitance of the capacitor has been described. There are various other properties of the ultrafine particle film that can be adjusted by irradiating laser light. First, (1) if the degree of adhesion with a substrate is tuned by laser light, it can be used as a surface lubricating coating or as a friction coefficient adjusting means. (2) By tuning the partial size or the entire size of the crystal grains or crystal grain boundaries of the ultrafine particle film 2 with laser light, the electrical characteristics, mechanical characteristics, optical characteristics, etc. of the ultrafine particle film can be adjusted.

As electrical characteristics, conductivity, resistivity, permittivity, etc. can be adjusted. (2A) By tuning the conductivity and the insulation resistance of the ultrafine particle film made of a conductor or an insulator, it can be used as a precision resistance of a circuit board,
(2B) By tuning the dielectric constant or capacitance of the ultrafine particle film made of a dielectric material, it can be used as a capacitor or a radio wave filter.

As mechanical properties, hardness, Young's modulus, coefficient of thermal expansion, surface roughness, etc. can be adjusted.
Then, by tuning the hardness (2C) and Young's modulus, it can be used as a bump or plating, and (2D)
If the coefficient of thermal expansion is tuned, it can be used as a bimetal or a linear expansion adjusting coating, and if the surface roughness of (2E) is tuned, it can be used as a surface roughness adjusting means or a fitting adjusting means of precision parts.

Further, as the optical characteristics, the refractive index, the reflection intensity, the intrinsic absorption wavelength, the light scattering characteristics, etc. can be adjusted. And, if the refractive index of the (2F) ultrafine particle film is adjusted, it can be used for optical recording and reading, and if the (2G) reflection intensity is adjusted, it can be used as a forgery prevention coating agent, and (2H) ) If the color is tuned by adjusting the intrinsic absorption wavelength (optical window), the light scattering property, etc., it can be used for the hue adjustment of pigments and coloring materials.

In addition to this, (3) tuning the physical adsorption amount of the ultrafine particle film can enhance the selectivity of the gas sensor, and (4) adjusting the chemical affinity can enhance the selectivity of the humidity sensor. (5) If the reactivity is adjusted, it may be used for tuning the electrical characteristics of the transducer.

According to the method of the present invention, even when different materials are mutually melted, they are mixed in the form of ultrafine particles,
By irradiating with laser light, the ion diffusivity can be increased, the composition can be taken beyond the stoichiometric constraint, and it is also suitable for use in doping impurities and the like.

[0028]

According to the present invention, the physical properties of the ultrafine particle film can be tuned by irradiating the ultrafine particle film with light and adjusting the light irradiation time and the irradiation intensity.

Moreover, the physical properties of the ultrafine particle film can be adjusted without changing the shape (pattern) of the ultrafine particle film with a small amount of energy. Further, there is no fear of damaging the substrate by tuning the ultrafine particle film.

Therefore, when the ultrafine particle film is used for a sensor, an electronic component, etc., it is possible to manufacture a sensor, an electronic component, etc. with high accuracy and reliability.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a gas deposition apparatus according to an embodiment of the present invention.

FIG. 2 is a partially cutaway front view showing an ultrafine particle film after being irradiated with a laser beam by the same apparatus.

FIG. 3 is a plan view showing a capacitor using an ultrafine particle film and a method for adjusting the capacitance thereof.

FIG. 4 is an explanatory view of the operation of the present invention.

FIG. 5 is a diagram for explaining another operation of the present invention.

[Explanation of symbols]

 1 circuit board 2 ultra fine particle film 15 laser light

Claims (2)

[Claims] 1. A method for controlling physical properties of an ultrafine particle film, which comprises changing the physical properties of the ultrafine particle film by irradiating the ultrafine particle film with light. 2. The ultrafine particle film is formed by a gas deposition method.
The method for controlling physical properties described in.