WO2005031036A1 - Ceramic film structure and forming method and device therefor - Google Patents

Abstract

A fine crystal ceramic film formed by an aerosol deposition method or the like is heat treated by laser irradiation using the optical characteristics of infrared rays, with respect to a ceramic material, of being easily absorbed by ceramics itself but reflected off metal, thereby providing a ceramic film structure in which a fine crystal ceramic film is not stripped off a substrate and which permits grain growth and defect recovery; and a forming method and device therefore. The forming method for the ceramic film structure is characterized by applying infrared laser to fine crystal ceramic film that has been formed in advance on a metal substrate.

Description

 Ceramic film structure and method and apparatus for forming the same

 Technical field

 The present invention relates to a ceramic film structure by aerosol deposition, a method and an apparatus for forming the same, and more particularly, to a ceramic film structure such as a dielectric, ferroelectric, magnetic or ferromagnetic material on a substrate. The present invention relates to a ceramics film structure capable of recovering grains and recovering defects without exfoliating the body, and a method and an apparatus for forming the same.

 Background art

 [0002] Conventionally, as a method of forming an electronic ceramic film such as a dielectric, a ferroelectric, a magnetic or a ferromagnetic material on a substrate made of metal or plastic, a balta is thinly machined and attached with an adhesive. There are two types of thin film forming technology: direct sputtering on a substrate, such as a sputtering method and a sol-gel method. However, each of these technologies is for forming a thick film with a thickness of 100 m or more and a thin film with a thickness of 1 m or less, and it is not possible to form a film of L m-100 m in a short time and with good performance.

 In recent years, cold spraying and gas spraying techniques have been developed to enable ultra-fine particles, such as submicron particles and nanoparticles, to collide with the substrate in a solid state without melting, and to form ultra-fine particles at low temperature and high speed. There are a deposition method and an aerosol deposition method. However, there is no example of forming a ceramic film using only a metal film in the cold spray method, and when a ceramic film is formed in the gas deposition method, a green compact with a film density of 55 to 80% is obtained. A heat treatment is indispensable to make a sintered body. Regarding the gas deposition method, as a heat treatment for forming a ceramics film, a technique of irradiating a laser perpendicular to the jetting direction of the ultrafine particle flow (Patent Document 1) and a technique of irradiating during the deposition (Patent Document 1) Reference 2) or a technique for irradiation after film formation (Patent Document 3, Patent Document 4, Patent Document 5).

On the other hand, there is a method of forming a film or structure of a brittle material called an aerosol deposition method. The aerosol deposition method transports an aerosol in which fine particles of a brittle material are dispersed in a gas, and jets and collides with the substrate surface at high speed to crush and deform the fine particles. By forming an anchor layer at the interface with the substrate and joining it together, and joining the crushed fragment particles together, a brittle material structure with good adhesion to the substrate and high strength is formed directly on the substrate. It is a technique that can be. This aerosol deposition method can form a very dense crystallized thick film with a density of 95% or more of the theoretical density directly on metal, glass, or plastic in a short time by the room temperature impact solidification phenomenon (Non-Patent Document 1) This is an epoch-making technology that is unparalleled in other processes, and can form the above film with a film thickness of 1 μm-100 μm with good performance in a short time without using an adhesive. Reference 2). The ceramic film formed by the aerosol deposition method is characterized by the fact that it is already crystallized as it is formed. When a device is formed due to having a crystal structure (Non-Patent Document 3), electric characteristics and electromechanical characteristics are not sufficiently exhibited as compared with characteristics of a Balta sintered body. Therefore, in order to obtain characteristics that can be put into practical use, it is essential to apply a heating process such as substrate heating or post annealing to promote film grain growth and recover defects. For example, in the case of lead zirconate titanate (PZT), which is one of the so-called piezoelectric materials, such as a microactuator optical scanner, conventionally, an electric furnace is used to perform post-annealing at 850 ° C or higher for at least 1 hour, and finally the Electric properties equivalent to those of the sintered body can be obtained (Non-Patent Document 4).

However, not only the substrate heating at the high temperature as described above, but also the external heating by the heating element provided inside the furnace like the electric furnace heating, not only the film but also the entire substrate is heated. Unnecessary other members may be heated to cause thermal damage and deviation in dimensional accuracy due to thermal stress, which may significantly reduce the performance of electronic ceramics, greatly hindering practical use. That is, as described above, the heat treatment is a force that is indispensable for the ceramic film to recover the crystal grain size, electrical characteristics, and electromechanical characteristics equivalent to those of the bulk sintered body. It is not possible to use fragile metal or plastic substrates. Specifically, the process temperature must be 600 ° C or less for metal substrates and 300 ° C or less for plastic substrates! In the case of an electric heating furnace, since the film itself is placed in the furnace, for example, in the case of a film on a metal substrate, the loss of metallic luster due to the thermal effect of the metal substrate, thermal melting, thermal deformation, and poor mechanical properties. And so on. In addition, since the entire film placed in the furnace is heated, separation occurs due to the difference in the coefficient of thermal expansion between the film and the substrate, and another layer consisting of a thick interdiffusion layer is formed at the interface between the film and the substrate. There is.

Patent Document 1: JP-A-2000-256832

Patent Document 2: JP-A-2000-260323

Patent Document 3: JP-A-5-44045

Patent Document 4: JP-A-6-49656

Patent Document 5: JP-A-6-116743

Non-Patent Document 1: Jun Akito, Maxim Lebedev: Materia 41 (2002) 459-466.

Non-Patent Document 2: Jun Akito: Ceramics 38 (2003) 363-368.

Non-Patent Document 3: Jun Akito and Masakatsu Kiyohara: Journal of the Society of Powder Technology 40 (2003) 46-54.

Non-Patent Document 4: J. Akedo and M. Lebedev: J. Cryst. Growth 235 (2002) 4

15 -420.

Disclosure of the invention

Problems to be solved by the invention

 As described above, the ceramic film formed by the gas deposition method is a green compact, and the laser is a heat treatment for forming this into a sintered body. The selection is made at a wavelength larger than the particle diameter of the ultrafine particles constituting the particle beam! / ヽ wavelength.

Further, not only a film formed by the aerosol deposition method but also a film formed by the sputtering method or the sol-gel method may be separated from the substrate depending on heat treatment conditions. Furthermore, when the film is directly irradiated with a laser and heated, the film is very easily peeled off due to the rapid heating and quenching process. Furthermore, in the technology combined with conventional laser irradiation, the difference in the coefficient of thermal expansion between the substrate and the film, the thermal conductivity of the substrate, the Young's modulus and the thickness depend on the type of laser, power, time, irradiation method, etc. In addition, there is a problem that peeling occurs due to the size, and it is particularly noticeable when a thick film is formed. In other words, conventional techniques combined with laser irradiation cannot cope with film peeling, and this is an issue that should be solved rather than practical. Furthermore, when irradiating a laser during film formation, the amount of heat radiation of the film decreases under reduced pressure. When laser irradiation is performed under the same conditions as those under atmospheric pressure, excessive heating occurs, which causes decomposition of the film and oxygen deficiency. Furthermore, in the case of lead-based ceramics such as lead zirconate titanate (PZT), which is a material for piezoelectric actuators, and lanthanum lead zirconate titanate (PLZT), which is a material for optical shutters, lead deficiency also occurs, resulting in a stoichiometric composition ratio. A problem arises in that the material collapses and the characteristics deteriorate significantly.

 In the present invention, a microcrystalline ceramic film formed by an aerosol deposition method or the like is subjected to a heat treatment by laser irradiation utilizing an optical property of an infrared ceramic material, which absorbs the ceramic itself and immediately reflects the metal back. An object of the present invention is to provide a ceramic film structure capable of performing grain growth and recovering defects without peeling off a microcrystalline ceramic film by a substrate force, and a method and an apparatus for forming the same.

 In addition, the present invention provides a technique for incorporating laser irradiation into an aerosol deposition method or the like, in which a substrate material is selected in terms of thermal expansion coefficient, thermal conductivity, Young's modulus, and substrate size to control laser power. To solve problems related to film peeling and to provide practical technology by devising the heating time and temperature control (heating and cooling patterns), laser scanning method, and the relationship between the particle beam and the laser irradiation position. With the goal.

Means for solving the problem

 In order to achieve the above object, a first invention of the present invention is a method for forming a ceramic film structure, comprising forming a microcrystalline ceramic film on a metal substrate, and then irradiating the microcrystalline ceramic film with an infrared laser. It is characterized by:

 The second invention according to the present invention is the first invention according to the first invention, wherein the irradiation with the infrared laser is performed at a temperature of 1 ° CZ μm—100 ° C. from the surface side of the microcrystalline ceramic film toward the metal substrate. It is characterized by maintaining a temperature gradient that decreases in the range of ° CZ μm.

 Further, a third invention of the present invention is characterized in that, in the above first or second invention, a microcrystalline ceramic film is formed on a metal substrate by an aerosol deposition method.

Further, a fourth invention according to the present invention is the method according to any one of the first to third inventions described above, wherein a unit area per unit area of the microcrystalline ceramic film by irradiation with an infrared laser is provided. It is characterized in that the upper limit of the film thickness and the film area of the microcrystalline ceramic film formed on the metal substrate is determined from the amount of heat input and the difference in the coefficient of thermal expansion between the metal substrate and the microcrystalline ceramic film.

 In a fifth aspect of the present invention, in the fourth aspect, the microcrystalline ceramics film is formed by lamination.

Further, the sixth invention of the present invention is the invention according to the fourth or fifth invention, wherein the microcrystalline ceramic film is made of lead zirconate titanate, and a unit area of the lead zirconate titanate film by irradiation of infrared laser is provided. When the heat input per unit is 10 j / mm ² or more, the film area of the lead zirconate titanate film is 100 mm ² or less or the film thickness is 20 m or less.

 Further, a seventh invention of the present invention is the invention according to any one of the first to third inventions described above, wherein the heat input due to the irradiation of the infrared laser is reduced by a heat input amount per unit area of the microcrystalline ceramic film, a laser beam. It is characterized by controlling by the diameter and irradiation time and by controlling the temperature gradually by bias heating after laser irradiation. Further, an eighth invention of the present invention is characterized in that, in the above-mentioned seventh invention, the temperature is controlled to be 300 ° C or less Zh until the temperature of the film becomes 300 ° C or less. ing.

In a ninth aspect of the present invention, in the method for forming a ceramic film structure, a film is formed by irradiating an infrared laser during the formation of the microcrystalline ceramic film on the metal substrate. It is characterized by irradiating an infrared laser in a gas pressure atmosphere! Further, the tenth aspect of the present invention, in the ninth invention described above, the low gas圧雰囲気is 1 X 10- ⁶ - are characterized by a LkPa.

 Further, an eleventh invention according to the present invention is the ninth or tenth invention according to the ninth or the tenth invention, wherein the infrared laser irradiation in a low gas pressure atmosphere after the film formation removes the substrate force of the film from the infrared laser. It is characterized by detection by another visible light laser.

According to a twelfth aspect of the present invention, a movable substrate holder for fixing a metal substrate is provided, a nozzle for spraying ceramic aerosol is provided on the surface of the metal substrate, and an infrared laser oscillator and an optical system are provided. Output from infrared laser oscillator The obtained infrared laser is irradiated to a microcrystalline ceramics film crystallized on a metal substrate via an optical system.

 A thirteenth invention of the present invention is the twelfth invention, characterized in that the substrate holder is rotatable.

 A fourteenth aspect of the present invention is the twelfth or thirteenth aspect of the present invention, wherein the aerosol jet using a reactive gas such as oxygen and nitrogen with respect to the oxidized ceramics and the nitrided ceramics through the nozzle. It is characterized by the fact that it is injected. In a fifteenth aspect of the present invention, in any one of the twelfth to fourteenth aspects described above, the optical system includes a collimator and a lens, and when an infrared laser is scanned over a wide range by a mirror, the film is always formed. It is characterized by controlling the power and beam diameter of the infrared laser so that the heat input to the laser beam is the same.

 Further, a sixteenth invention of the present invention is characterized in that, in any one of the twelfth to fifteenth inventions described above, a heating means for heating the aerosol carrier gas and the metal substrate is provided. .

 Further, a seventeenth invention according to the present invention is the method according to any one of the twelfth to sixteenth inventions, wherein the heating means controls the degree of heating of the ceramic film in accordance with the thermal conductivity of the metal substrate. It is characterized by the fact that

Also, eighteenth aspect of the present invention, in any one invention of the twelfth to seventeenth mentioned above, a metal substrate at least the coefficient of thermal expansion is a combination of the following substrates 30 X 10- ⁶ Z ° C It is characterized by the fact that it has been used.

 In a nineteenth aspect of the present invention, in any one of the twelfth to eighteenth aspects, a metal substrate formed by combining at least a base material having a thermal conductivity of 450 WZmK or less is used. As a feature! Puru.

 A twentieth invention of the present invention is characterized in that, in any one of the twelfth to nineteenth inventions described above, a metal substrate having a thickness of at least 110 m is used.

Further, a twenty-first invention of the present invention is the metal according to any one of the twelfth to twentieth inventions described above, wherein at least a base material having a Young's modulus of 500 GPa or less is combined. It is characterized by using a substrate.

 A twenty-second invention of the present invention is characterized in that, in any one of the twelfth to seventeenth inventions described above, SUS430 is used as the metal substrate.

In addition, the 23 invention of the present invention, the thermal expansion coefficient of 30 X 10- ⁶ Z ° C or less, thermal conduction rate thicknesses 450WZmK less and the Young's modulus is a combination of the following substrates 500GPa is 1 one It is characterized in that a microcrystalline ceramic film is formed on a metal substrate of 100 m, and the microcrystalline ceramic film is irradiated with an infrared laser.

 A twenty-fourth aspect of the present invention is the invention according to the twenty-third aspect, wherein the metal substrate is SUS430.

 Further, a twenty-fifth aspect of the present invention is characterized in that, in the twenty-third aspect or the twenty-fourth aspect, the material composition of the microcrystalline ceramic film is mainly composed of lead zirconate titanate.

 A twenty-sixth aspect of the present invention is the liquid crystal display device according to any one of the twenty-third to twenty-fifth aspects, wherein the thickness of the microcrystalline ceramic film is 0.1-20 / zm.

 Further, a twenty-seventh aspect of the present invention is the liquid crystal display device according to any one of the twenty-third to the twenty-sixth aspects, wherein the crystal grain size of the microcrystalline ceramic film is closer to the vicinity of the film surface and the vicinity of the metal substrate interface. It is characterized by a gradient distribution so that it becomes smaller.

 In a twenty-eighth aspect of the present invention, the interdiffusion layer formed at the interface between the microcrystalline ceramic film and the metal substrate has a thickness of lnm-200 nm in any one of the twenty-third to twenty-seventh aspects. It is characterized by being in the range.

The invention's effect

 According to the present invention, the following effects can be obtained.

 (1) It is possible to obtain a ceramic film structure in which separation between a microcrystalline ceramic film and a substrate is prevented, and in which grain growth and defect recovery of the microcrystalline ceramic film are performed.

(2) Infrared laser irradiation does not have a thermal effect on the substrate unlike heating in an electric furnace, so an inexpensive stainless steel substrate or the like can be used. Further, a ceramic film structure having higher remanent polarization than that obtained by heating in an electric furnace can be obtained. (3) Selective heat treatment is possible, and heat energy can be used efficiently.

(4) Since the laser can be applied only to the film to be heated, there is almost no thermal effect on the metal substrate. Even if a laser beam is applied to a metal part, the laser used is reflected at the metal part because of the infrared wavelength, and only the film part is absorbed and heated.

 (5) By further laminating a film on a thin film that does not cause film peeling, a thick film without film peeling can be obtained. Further, a laminate of ceramic films having different characteristics such as a ferroelectric film and a ferromagnetic film can be obtained.

 (6) By selecting an appropriate coefficient of thermal expansion, thermal conductivity, Young's modulus and substrate size as a substrate, a ceramic film structure without peeling can be obtained. Also, the degree of heating of the film by the substrate can be controlled.

 (7) According to the laser irradiation, the film is heated from the inside by laser absorption of the film, so that grain growth and defect recovery can be performed at a lower temperature than in the case of electric furnace heating.

 (8) The crystallinity and grain growth of the film due to the thermal effect of laser irradiation are most remarkable near the surface of the irradiated film, and the effect decreases toward the interface with the substrate. The crystal grain size of the internal film closer to the surface than the film can be grown.

 (9) Since the thermal effect of laser irradiation has a gradient in the film thickness direction, it is possible to reduce the hetero phase composed of the interdiffusion layer formed at the interface between the film and the substrate, and to reduce the thickness of the hetero phase to lnm It can be suppressed to the range of 200 nm.

 (10) By rotating the substrate, the scanning speed can be increased, the film thickness can be controlled to be very thin, and the heat input of laser irradiation can be reduced.

 (11) By irradiating the laser in a low-gas atmosphere, it is possible to efficiently apply low heat input to the film, which suppresses the heat radiation of the film surface force. Can be suppressed.

 (12) In addition to irradiating the infrared laser during film formation, by irradiating the infrared laser after the film is formed, a film having a high remanent polarization value can be obtained, and the infrared laser is irradiated only during the film formation. The effect of remarkable improvement of the characteristics was observed as compared with those obtained.

(13) By detecting the reflected light of the visible light laser that irradiates the film formation part, The presence can be checked immediately.

 Brief Description of Drawings

 FIG. 1 is a view for explaining an example of a method by which a microcrystalline ceramic according to the present invention can form a thick film.

 FIG. 2 is an explanatory view of a heating pattern by laser irradiation according to the present invention.

 FIG. 3 is an explanatory diagram of a beam profile of a laser according to the present invention.

 FIG. 4 is a diagram illustrating an example of a structure according to the present invention in which the heating state of a film can be controlled by the thermal conductivity of a substrate.

 [Fig. 5] Fig. 5 is a graph showing the temperature characteristics of the back of the stainless steel substrate on which no film is formed and the stainless steel substrate with a PZT film, with respect to one laser irradiation.

 FIG. 6 is a schematic diagram showing an apparatus for forming a ceramic film structure according to the present invention.

 [FIG. 7] FIG. 7 is an optical micrograph of a film surface that was not peeled off by laser irradiation and a film surface that was peeled off.

 [Fig. 8] Fig. 8 is a graph showing electric field strength-residual polarization value characteristics of an untreated PZT film as-deposited and a PZT film subjected to electric furnace heating and laser irradiation.

 FIG. 9 is a graph showing remanent polarization characteristics of a PZT film when an infrared laser is irradiated after the film formation in addition to the infrared laser irradiation during the film formation.

 [Figure 10] Figure 1Ο shows cross-sectional transmission electron microscope images (upper figure) and electron beam diffraction images (lower figure) of the substrate-side PZT film and the internal PZT film near the surface of the PZT film formed directly on the stainless steel substrate. It is shown.

 FIG. 11 shows cross-sectional transmission microscope images of an electric furnace annealing and a laser annealing of a PZT film directly formed on a stainless steel substrate.

 Explanation of symbols

[0007] 1 Deposition chamber 1

 2 Vacuum pump

 3 X— Y— Z stage

 4 Board holder a

5 Metal substrate 6 nozzles

 7 CO2 laser oscillator

 8 Controller

 9 No Monitor

 10 Shutter

 11 Function generator

 12 Oscilloscope

 13 Optical system a

 14 Infrared transmission window

 15 Power monitor b

 16 PCB holder b

 17 Optical system b

BEST MODE FOR CARRYING OUT THE INVENTION

 The present invention relates to a ceramic film structure and a method and an apparatus for forming the same, wherein a laser is applied to a ceramic film formed on a substrate so that the film does not peel off the substrate force, and grain growth and defect recovery of the ceramic film are performed. Can be realized.

 The ceramic film formed on the substrate is already dense and crystallized, and laser irradiation is used to promote the growth of fine crystal grains and recover defects. The laser for irradiation is an infrared laser oscillating in the infrared region, and a carbon dioxide laser is optimal. Carbon dioxide gas lasers have the property of absorbing many ceramics and hardly absorbing metals as compared to YAG lasers having the same wavelength in the infrared region. In other words, by utilizing this property, only the ceramic film can be effectively heat-treated, and only the ceramic film formed on the metal surface of the substrate or the ceramic film smaller than the beam diameter can be selectively heat-treated. It is possible to do.

Also, since the laser can be irradiated only to the film to be heated, there is almost no thermal effect on the metal substrate. Even if the laser is applied to a metal part, the laser used is of an infrared wavelength, so it is almost reflected by the metal part, and absorption occurs only in the film part, resulting in calorie. Heat treated.

 Furthermore, from the viewpoint of utilizing only the thermal effect of the laser, the laser power required for irradiation is sufficient to be a class 4 laser of 100 W or less, and the laser power is appropriately controlled to satisfy the above points. Then, infrared semiconductor lasers and YAG lasers can be used. The temperature at which grain growth and defect recovery are caused in the ceramic film by such heating depends on the target ceramic material, but a temperature of at least 600 ° C is required, and a temperature of 800 ° C or more is preferable. Required. In addition, laser irradiation as described above has a sufficient effect of recovering characteristics even in a film formed by a sputtering method, a sol-gel method, a CVD method, or the like.

 The ceramic film formed on the substrate is preferably formed by aerosol deposition. In order to form microcrystalline ceramics that can withstand the practical application of the present invention, it is necessary that the film before laser irradiation has already been crystallized. Furthermore, the film must be dense and have sufficient mechanical properties, and only need to be at a level where heating promotes grain growth and recovers defects. The aerosol deposition method uses ultra-fine particles of ceramic sintered body with a particle size of about 0.02 to 2 m to form a film crystallized on a metal, glass or plastic substrate at room temperature with a high adhesion of 20 MPa or more. This is the only method that can form films at high speed and with high precision. The microstructure of the film formed at room temperature is characterized by a microcrystalline structure with a crystal grain size of about 5 nm to 80 nm.

When a carbon dioxide laser is applied to a ceramic film on a metal substrate, the film absorbs the laser and generates heat, and the underlying metal substrate is heated only by heat conduction from the film, which is not possible with laser absorption. At this time, the larger the film thickness and the film area, the more the carbon dioxide gas laser is absorbed and heat is generated. As a result, thermal shock occurs due to the difference in the thermal expansion coefficient between the base material and the base material and the film, and film separation occurs. . Therefore, it is necessary to determine the upper limit of the film thickness and the film area with respect to the laser power to be irradiated and the coefficient of thermal expansion of the metal substrate, and to determine the range of the film thickness in which film peeling does not occur. When the PZT film on a stainless steel (SUS304) substrate has a film area of at least 100 mm ² or a film thickness of 20 m or more, peeling is caused by heat input of at least lOjZmm ² or more. The film thickness is 20 m, preferably 0.1-20 / zm, more preferably 110 m. Laser irradiation on a film with an area smaller than 100 mm ² even if the A ceramic film having a thickness of 20 μm or more can be formed without laminating a ceramic film by laminating a ceramic film on a film that does not peel and having a thickness of less than m. It is also possible to laminate ceramic films having different characteristics such as a ferroelectric film and a ferromagnetic film.

 [0010] When a ceramic film formed on a substrate is irradiated with a laser, it is necessary to consider a heat input step for the film. In other words, heat input is represented by the product of laser power per unit area and irradiation time, so it is necessary to control the laser power, beam diameter, and irradiation time. The beam diameter can be controlled by a lens. When the area of the PZT film is significantly larger than the beam diameter, the laser is not only the strain introduced during film formation that acts on the interface between the film and the substrate. Occurs.

 In particular, it is considered that film peeling occurs when the temperature suddenly drops after laser irradiation. Therefore, it is effective to perform bias heating to prevent the film temperature from dropping rapidly after laser irradiation as shown in Fig. 2. For example, by slowly lowering the laser power, expanding the beam diameter with a lens to suppress sudden changes in heat input, or by using a preheating laser after irradiating the heating laser. It is possible to prevent film peeling. In addition, the actual cooling pattern by heating in an electric furnace is furnace cooling, but if the cooling pattern is set so that the cooling rate does not exceed 300 ° CZh until the furnace temperature drops to 300 ° C, film peeling will occur. Has not occurred. Therefore, in the heat input step by laser, after laser irradiation, bias heating may be performed at a temperature lowering rate of 300 ° CZh or less until the temperature of the film becomes 300 ° C or less. If a film that does not cause film peeling can be formed by the above-mentioned technology, a ceramic film is further formed on the film, and then a laser is irradiated! / By repeating the process, film stacking is realized, and a thicker film is realized. For example, it is possible to stack a ferroelectric film and a ferromagnetic film (Fig. 1).

When irradiating a carbon dioxide gas laser inside the chamber after film formation, the inside of the chamber is under reduced pressure, so that the heat radiation of the same laser as under the atmospheric pressure reduces the amount of heat released, and the thermal balance is lost. The film is heated more than necessary, and as a result, the film is peeled off. Therefore, it is necessary to consider the atmosphere during laser irradiation from the viewpoint of heat radiation. Where the thermal balance is Is expressed.

Where m is the total heat capacity of the irradiated object, t is the irradiation time, T is the initial temperature, and T is the laser i 0

Temperature at one irradiation, I is absorption power, e is emissivity, σ is Stefan-Boltzmann constant, S

 0

Is the surface area of the irradiated object, and G is the thermal conductivity of the atmosphere.

 Conversely, even under reduced pressure, the supply of reactive gases such as oxygen and nitrogen for oxidized ceramics and nitrided ceramics, and pressure control, will result in lower heat input than when no reactive gas is supplied. It is thought that the laser accelerates the grain growth of the film. That is, a reactive gas such as oxygen or nitrogen is used for the particle beam (aerosol jet), or mixed with an inert gas such as helium or argon, or a separate nozzle for supplying a reactive gas is provided. There is a way. It is preferable that the reactive gas is blown close to the laser irradiation position so that the nozzle does not block the aerosol jet or the laser. The method of supply is to make the gas supply and laser irradiation perpendicular to the aerosol jet, thereby creating an active ultra-fine particle flow before the ultra-fine particle flow reaches the substrate or film to grow the particles. Supply of gas and laser irradiation to the position where a non-thermal equilibrium state occurs, that is, the position where the aerosol jet collides with the substrate or the film, to promote the grain growth, There is a method that promotes grain growth by supplying gas and laser irradiation.

In addition, when heating a film with a wider range than the laser beam diameter, it is necessary to scan the laser with a mirror. In that case, the irradiation area on the film changes depending on the irradiation angle of the laser. Therefore, it is important to control the power and beam diameter so that the heat input to the film is always the same, in order to realize a uniform heat treatment that is more than just suppressing the film separation. Also, it is thought that there is a remarkable temperature gradient near the periphery of the beam. The beam profile is preferably such that the beam intensity is larger at the periphery than at the center (Fig. 3).

 When irradiating a laser during film formation, the positional relationship between the aerosol jet and the laser is also very important. When the laser is irradiated before and after with respect to the scanning direction of the aerosol jet, the film thickness is thinner than when the irradiation is performed after the film formation, and the same result as the laser irradiation effect after the film formation is obtained with lower laser power. Could be obtained. In addition, when the laser is irradiated to the position where the aerosol jet collides with the substrate, the non-equilibrium process by rapid heating and quenching of the laser is superimposed on the non-equilibrium film formation process unique to the aerosol deposition method. The non-thermal equilibrium process is spurred, for example, the control of physical properties by introducing intentional defects or controlling the amount of defects

However, there is a possibility that functional ceramics with completely new mechanical and electrical properties and crystal structure can be formed. On the other hand, when irradiating a laser to the aerosol jet, control of laser power controls the defects in the film by cleaning the ultra-fine particles by heating, and the crystal grains are large by the growth of the ultra-fine particles! Is done.

 However, when irradiating the laser beam back and forth with respect to the scanning direction of the aerosol jet, the carrier gas flowing on the substrate surface cools the film, so it is necessary to consider the balance between heat absorption and heat dissipation of the laser irradiation surface. In addition, when the laser is applied to the position where the aerosol jet collides with the substrate or the film, the substrate and the formed film exposed to the aerosol jet ejected from the nozzle cap may be locally cooled by adiabatic expansion. Therefore, a very large temperature gradient occurs in the film thickness direction and the scanning direction, and as a result, film peeling due to thermal shock may occur.

As a method of solving the above-mentioned cooling problem, it is possible to suppress the thermal shock by raising the temperature of the carrier gas and the substrate to several hundred degrees in advance. The temperature of the film before laser irradiation is preferably 600 ° C or less in consideration of prevention of peeling due to thermal shock, and preferably at most about 400 ° C in consideration of damage to the substrate. As a method of heating the substrate, laser irradiation is used, and the input energy density is changed by controlling the beam diameter or laser power, so that it is possible to distinguish between preheating of the substrate and heat treatment of the film. I do. At that time, a separate laser for substrate surface temperature sensing It is assumed that the input energy density can be controlled by feed knocking to the laser controller for pre-heating the substrate and for heat treatment of the film by using the above method. In addition, when laser irradiation is performed while heating the substrate or the carrier gas, the thermal shock due to the laser irradiation is reduced, controllability is improved, and practicality is considered to be high.

Other means suppressing film peeling method in addition to infrared radiation, 1 X 10- ⁶ kPa after film formation, to morphism irradiation of infrared laser at a low gas pressure atmosphere and more preferably 50- LkPa during deposition There is. As a result, it is possible to efficiently apply a lower heat input to the film as described above, and the heat radiation of the film surface force is suppressed, so that the heat release effect, that is, compared with the case of the atmosphere or a high gas pressure atmosphere, is released. Cooling is suppressed, and rapid cooling, which is one of the major causes of film peeling, can be suppressed. Furthermore, since the aerosol jet alone is stopped after film formation and the infrared laser is irradiated, the structure of the substrate film mask does not change at all in the state of film formation. Good accuracy V ヽ Thick film or multilayer film can be formed.

 By providing a means for irradiating a visible light laser to the film forming part separately from the infrared laser for heat treatment described above, when the film is peeled from the substrate during the infrared irradiation after the film formation, the visible light laser is irradiated. Since the light is reflected on the surface where the substrate is peeled off, by detecting the light, the presence or absence of the film peeling can be immediately confirmed.

Even if the ceramic film generates heat by absorbing the carbon dioxide laser, if the thermal conductivity of the substrate is too high, the ceramic film is not heated to such an extent that the characteristics are improved. In this case, when the film is heated by laser irradiation with a larger heat input to improve the characteristics of the film, the surrounding members are also heated simultaneously with the film. That is, as a result, the surrounding members that are not covered by the ceramic film are damaged by heat. Conversely, if the thermal conductivity of the substrate is too low, a large shear force due to the difference in the thermal expansion coefficient occurs at the bonding interface between the ceramic film to be heated and the substrate, and film peeling occurs. At this time, if the thickness of the substrate is not too thin, the substrate may be greatly deformed by the generated shear force, or may be significantly discolored or deteriorated by thermal influence. Therefore, it is important to select an appropriate thermal expansion coefficient, thermal conductivity, and substrate size for the substrate. Conversely, the degree of heating of the film can be controlled by designing and combining the materials of such substrates, especially with thermal conductivity (Fig. 4). [0015] As a ceramic film irradiated with a carbon dioxide gas laser, a film containing lead zirconate titanate (PZT) as a main component is preferable, and its crystal structure is a dense nanocrystalline structure. It is necessary to control the grain growth to a crystallite size of 0.08 m or more and 2 μm or less by laser irradiation controlled to suppress the above-mentioned film peeling. This is because when the electromechanical properties of a piezoelectric material such as a PZT actuator are used, the large piezoelectric response and high mechanical strength, temperature stability, and frequency stability can be achieved by adjusting the crystal grain size range as described above. This makes it possible to improve the performance as an actuator, for example, because depolarization is unlikely to occur.

[0016] As a material of the substrate, a stainless steel substrate having a Young's modulus similar to that of single crystal silicon is preferable. As shown in Table 1, the thermal conductivity of stainless steel substrates is generally lower than that of pure metals (S US304 = 17.3 WZmK, SUS430 = 26 WZmK), so the formed ceramics film is easily heated by laser irradiation . Still considering the thermal bulging expansion coefficient among the stainless steel substrate, the SUS430 thermal expansion coefficient smaller than SUS304 (SUS430: 10. 5 X 10- 6 Z ° C, SUS304: 16. 3 X 10- 6 Z ° C) The use of SUS430 is considered to be effective in reducing the thermal stress during laser irradiation. For pure metals, it is considered appropriate to use a titanium substrate that exhibits a thermal conductivity (17 WZmK) similar to that of stainless steel and a low thermal expansion coefficient (8.6 X 10 "V ° O). conditions of the substrate without peeling the total to at least the thermal expansion coefficient of less 30 X 10- ⁶ Z ° C, preferably 1 X 10 "V ° C one 30 X 10- ⁶ Z ° C, more preferably 1 X 10 ^{- 6 Z ° C- 20 X 10-} 6 Z ° C, thermal conductivity of 450 W ZMK less, preferably 0. 01- 450WZmK :, more preferably 10- 150WZmK der Rukoto component force Ru.

table 1 Material Tensile coefficient [X 1 «H Thermal conductivity [W / mK] Young's modulus [GPa]

 Al 23.1 240 68.5

 Ir 6.4 145 514

 Au 14.2 313 79.5

 Ag 18.9 422 73.2

 Si 2.6 168 105

 W 4.5 163 354

 Ta 6.3 58 186

 Ti 8.6 17 108

 Cu 16.5 395 123

 Ni 13.4 83 201

 Pt 8.8 72 168

Al ₂ 0 ₃ ~ 7.8 ~ 20 -400

Zr0 _{2 to} 9.2 to 3.3 to 210

 AIN ~ 4.6 ~ 170 ~ 320

 SiC -4,2 ~ 75 ~ 390

Si ₃ N * ~ 3.5 ~ 25 ~ 290

 SUS304 16.3 17.3 193

 SUS430 10.5 26 200

 RT-100. C On the other hand, from the viewpoint of mechanical properties, materials with low Young's modulus! / Aluminum (68.5 GPa), gold (79.5 GPa), silver (73.2 GPa), etc. are also effective as a substrate material (Table 1). ). That is, since the Young's modulus is small and soft, the shear stress acting on the interface between the film and the substrate is alleviated even if the difference in thermal expansion coefficient is large. Therefore, these materials are effective not only as the material of the substrate but also as a relaxation layer inserted between the film and the substrate. As described above, a Young's modulus of at least 500 GPa or less, preferably 0.001 to 500 GPa, more preferably 50 to 100 GPa is effective in preventing film peeling.

According to the present invention, a dense and crystallized PZT thick film formed on a SUS304 stainless steel substrate having a thickness of 100 μm by aerosol deposition method is used to promote grain growth and its electrical and electromechanical properties. To improve this, the film was irradiated with a carbon dioxide laser with a power of 13 W at a beam diameter of 4 mm. As a result, when laser irradiation is performed for 50 seconds, film peeling occurs when the film thickness is 20 μm or more, and when the film thickness is 5 μm or less, film peeling does not occur. The substrate was hardly affected by heat, and only the film was heat-treated. Electron microscopy of the PZT film irradiated with laser showed grain growth and necking, and showed a high remanent polarization value of 30 CZcm. This value is superior to that of the film heated by an electric furnace, and even if a stainless steel substrate on which no PZT film is formed is irradiated with a laser, the substrate has no change in force. We found that selective heating of small PZT piezoelectric devices formed on inexpensive stainless steel substrates could be realized in a short time.

 Example 1

 FIG. 5 shows the stainless steel substrate on which nothing was formed and the stainless steel substrate on which 4 の having a film thickness of 45 μm and 45 μm were formed were irradiated with carbon dioxide gas laser. It is a graph which shows a temperature change. The data port logger also recorded the force 10 seconds before the laser irradiation and irradiated the laser for 50 seconds. The laser irradiation shows that the maximum temperature can be reached in less than 10 seconds from the start of irradiation. When nothing was deposited, the temperature rose only about 120 ° C. when the stainless steel substrate was irradiated with a laser, and no deformation of the substrate or a change in the color of the substrate surface was observed. On the other hand, when the stainless steel substrate on which the PZT film was formed was irradiated with a laser, a rise in temperature on the back of the substrate of 280 ° C to 350 ° C at 45 μm and 600 ° C at 45 ^ m was confirmed. It can be seen that the absorption characteristics of the carbon dioxide laser differ between the PZT film and the stainless steel substrate. On the other hand, when the furnace was heated at 600 ° C for 1 hour, the entire stainless steel substrate turned brown! In addition, in the case of electric furnace heating, the ceramic film is heated from the outside by radiant heat of a heating element in the furnace, but in the case of laser irradiation, the film is internally heated by laser absorption. Therefore, the effects of grain growth and defect recovery at a lower temperature than in the case of electric furnace heating by laser irradiation are expected.

 Example 2

FIG. 6 is a schematic view for explaining a microcrystalline ceramic forming apparatus of the present invention, and the microcrystalline ceramic is formed by aerosol deposition. That is, in the drawing, reference numeral 1 denotes a film forming chamber, which is evacuated to about 50-lkPa by a vacuum pump 2 and adjusted to about 50-1 × 10 ³ Pa by introducing an atmosphere gas. Deposition chamber 1 An X-Y-Z stage 3 is installed inside, connected to the substrate holder a4, and can be scanned by a program. The metal substrate 5 is fixed to the substrate holder a4, and can freely change its direction with respect to the aerosol jet ejected from the nozzle 6 or the irradiation of the infrared laser introduced into the film forming chamber 11. The substrate holders a4 and bl6 are provided with a rotation mechanism. The laser irradiation time is controlled by the number of rotations, or the substrate is coaxially rotated to reduce the film thickness and the unevenness of the laser irradiation on the film. Suppression is possible. By controlling the film thickness with an accuracy of lOOnm, it is possible to reduce the heat input to the laser film, which can be achieved only by preventing film peeling by controlling the film thickness. In other words, it is difficult to scan more than lOmmZs by moving the substrate using the XYZ stage. Therefore, by increasing the scanning speed by one rotation by using a motor, the thickness of one layer can be extremely increased. The thickness can be reduced, and heat input by laser irradiation can be reduced. Further, by laminating a single layer as described above, a film having a particle size of 0.02 to 2 m can be formed with a lower heat input than when the XYZ stage is used. At this time, the peripheral speed of the substrate is preferably lOmmZs-lkmZs.

 The laser is output by a carbon dioxide laser oscillator 7 and can be turned on and off by a controller 8. The laser output from the carbon dioxide laser oscillator 7 is monitored by a power monitor a9, and a laser with a desired power can be output by interlocking with the controller 8.

 The laser can also be turned on and off by the shutter 10, and by making it independent of the controller 8, the shutter can be closed until the infrared laser oscillator 7 oscillates the laser stably. The shutter 10 can adjust the opening and closing time of the shutter by a signal generated by the function generator 11, thereby controlling the irradiation time of the laser. The signal waveform of the function generator 11 is monitored by an oscilloscope 12.

When irradiating laser during the formation of a ceramic film by the aerosol deposition method, the film is irradiated onto the film through an infrared transmission window 14 provided in the film formation chamber 11 by an optical system al3 equipped with a collimator, lens, and mirror. Is done. The irradiated laser can have a desired beam diameter by the optical system al3. Also, the laser Alternatively, irradiation can be performed before or after the aerosol jet, or during the aerosol jet, and two-dimensional scanning can be performed by controlling a mirror in the optical system al3. Immediately before being introduced into the deposition chamber 11 Since the laser power may be slightly lost by the optical system al3, it can also be monitored by the power monitor b15 to obtain a more accurate laser power.

 When laser irradiation is performed after the formation of the ceramic film by the aerosol deposition method, the substrate with the ceramic film is fixed to the substrate holder bl6 shown by the broken line and subjected to heat treatment. The diameter of the laser beam irradiated on the film can be adjusted by using an optical system bl7 having a collimator and a lens after the shutter 10. The substrate holder bl6 may be installed inside or outside the film forming chamber 11.

Example 3

In the aerosol deposition method, a PZT film was formed on a 100 mm thick stainless steel (SUS304) substrate. The surface of the substrate was not particularly mirror-polished. The substrate was fixed on a substrate holder a4 connected to the XYZ stage 3, and scanned in a uniaxial direction at a speed of 1.25mmZs for 30mm. The film formation atmosphere was about 40 Pa, and an aerosol jet of PZT fine particles and helium gas was sprayed from the nozzle 6 onto the substrate. The nozzle used had an orifice shape with a tip outlet of 10 × 0.4 mm ² , and the distance between the nozzle and the substrate was 10 mm. PZT fine particles used were commercially available sintering materials prepared by the solid phase method, and the composition was Pb (Zr, Ti) O and the particle size distribution was 0.08-0.5 μm. Helium gas flow

 0.52 0.48 3

The volume was 2.5 lZmin. The film was formed using a mask, and a PZT film was formed in an area of 4 mm square.

The PZT film prepared above was irradiated with a carbon dioxide laser. The irradiation atmosphere was atmospheric pressure and air, the laser power was 13 W, the beam diameter was 4 mm, the irradiation time was 50 seconds, and no measures were taken against film peeling due to substrate bias heating. As a result, when the thickness of PZT was 20 / zm or more, all the films grew red during laser irradiation, and peeling occurred at the size of the beam diameter. On the other hand, when the film thickness is 20 / zm or less, some films do not peel off, and when the film thickness is 5 m or less, no film separation occurs in all films. Was confirmed to have turned yellow.

 FIG. 7 is an optical micrograph of a typical exfoliated film and a non-exfoliated force film. The result is that as the film thickness increases, the amount of heat absorbed by the film by the laser increases, and a large shear force occurs at the interface due to the difference in the coefficient of thermal expansion between the film and the substrate, which exceeds the adhesion of the film to the substrate and peels off. Is considered to have occurred. Film detachment was also observed when the laser irradiation time was longer than 50 seconds, and is considered to be the same factor as above.

Example 4

 When the same experiment was performed using a stainless steel substrate having a thickness of 50 / zm, significant deformation of the substrate due to thermal influence and large discoloration of the back surface of the substrate were confirmed after laser irradiation. Inspection of the electric field strength remanent polarization characteristics showed a hysteresis curve, but a remarkable decrease in withstand voltage and deformation of the hysteresis curve due to the influence of leakage current were observed. This is due to the difference in the thermal expansion coefficient between the film and the substrate caused by the heat conducted from the film heated by the laser irradiation to the substrate, resulting in large thermal deformation of the substrate. It is probable that the film was easily peeled or a gap was formed in the film, and an electrical short-circuit path was likely to be formed when the upper electrode was formed. This is because heating the substrate during laser irradiation reduces the thermal stress generated at the interface between the film and the substrate, and instead of shortening the irradiation time, increasing the laser power to control the heat input, which reduces the thermal effects of the substrate. The problem can be solved by heating the film to such an extent that it will not be affected.

 Next, heat the substrate at 600 ° C on PtZAl O substrate and PtZTiZSiO ZSi substrate.

 2 3 2

A laser having a film thickness of 20 μm, which was formed by the aerosol deposition method, was irradiated with a laser under the conditions described in Example 3 while performing the above steps. As a result, PZT on Pt / AlO substrate changes.

 twenty three

Although it was colored, film peeling and substrate crushing occurred. On the other hand, on PtZTiZSiO ZSi substrate

 2

The PZT showed no change at all, and showed no change even when the laser was focused with a lens and the energy density was increased. After that, the electrical characteristics were measured, and only a slight improvement in the characteristics compared to the unirradiated film was observed. This result is considered to be due to the fact that the thermal conductivity of the substrate is a major factor in addition to the difference in the coefficient of thermal expansion of the substrate as clarified in Example 1. That is, when laser is irradiated on PZT on Pt / Al O substrate, Pt becomes thermal conductivity

 twenty three

Because the film thickness is very thin, the underlying Al 2 O 3 substrate is also immediately heated. But Al O Although the thermal conductivity of the three substrates is about the same as that of stainless steel and the coefficient of thermal expansion is small, it is considered that they are brittle materials unlike metallic materials, and thermal shock is caused by rapid thermal quenching by laser irradiation, resulting in crushing. Regarding this problem, PtZAl O substrate after laser irradiation

 The solution can be solved by heating the substrate, heating with a preliminary laser, and irradiating the laser as shown in Fig. 1 so that 23 is not rapidly cooled.

 On the other hand, when ρζτ on the ptZTiZsio Zsi substrate is irradiated with laser,

 2

The Si substrate is heated through the high thermal conductivity Pt layer and the ultra-thin Ti layer. However, although the thermal expansion coefficient of the Si substrate is small, the thermal conductivity is very large, so it removes heat from the heated film, and as a result, PZT is considered to be a force not heated to 600 ° C or more. Can be In this case, the heat deprived from the film is averaged over the entire Si substrate, but if the input heat is increased by lengthening the irradiation time so that the film is expected to be modified, the Si substrate will also be heated. As a result, the members around the film are damaged by heat. Therefore, the problem can be solved by increasing the laser power and controlling the irradiation time and irradiation pattern so that at least the members around the film do not become more than 400 ° C due to heat conduction. Table 1 shows the thermal expansion coefficients and thermal conductivity of typical metals and ceramics.

Example 5

 3.5 Two PZT films with a thickness of 5 μm were formed on a stainless steel (SUS304) substrate under the same conditions as in Example 1, one was heated in a general-purpose electric furnace, and the other was irradiated with laser. Heat treatment was performed. The electric furnace was heated from room temperature to 600 ° C at a heating rate of 300 ° CZh in an air atmosphere, kept for 1 hour, subjected to a heat treatment, and then cooled in the furnace. Laser irradiation was performed under the same conditions as above. Then, the surface of the heat-treated PZT film is polished and cleaned using a diamond paste, and then a lmm square gold electrode is formed by a sputtering method using a mask. And the case of laser irradiation were compared.

FIG. 8 is a graph showing electric field strength remanent polarization value characteristics when an unprocessed PZT film as-deposited on a stainless steel substrate and an electric furnace heating and laser irradiation are performed. The film thickness was 3.5 m in both cases. An untreated PZT film that has been formed shows a linear behavior that passes through the origin with respect to the electric field strength. It turns out that it is paraelectric rather than dielectric. This is a film formation process that uses the impact solidification phenomenon of the aerosol deposition method, so that various structural defects and residual stresses are introduced into the film at the time of film formation, and furthermore, the formed film has fine crystal grains. It is considered that the domain inversion is very difficult because of the structure. On the other hand, a hysteresis loop was drawn for the electric field intensity for the PZT film that was irradiated with the electric furnace heating laser. This indicates that the PZT film formed by aerosol deposition and exhibiting a paraelectric property exhibits ferroelectricity, which is the original characteristic, because the crystal growth and defect recovery of microcrystals are performed by heat treatment. Conceivable.

When the electric furnace heating and the laser irradiation were compared, the electric furnace heating showed a residual polarization value of 16 CZcm ² , whereas the laser irradiation showed a higher residual polarization value of 30 CZcm ^2. Indicated. In addition, as a result of electron microscopic observation and X-ray diffraction of the laser-irradiated film and the non-irradiated film, the laser-irradiated film showed more necking and grain growth than the non-irradiated film. The X-ray diffraction peak was also sharp. From the above results, in the electric furnace heating, the film and the entire stainless steel substrate are heated by the radiant heat of the heating element, whereas the laser irradiation is irradiated and absorbed only to the film portion and converted to heat, so that almost only the film is heated. Is considered to have been efficiently heat-treated. In addition, due to the difference in laser focusing properties and the absorption characteristics of carbon dioxide lasers for ceramics and metals, the stainless steel substrate does not overheat as in electric furnace heating, and the oxide on the metal substrate surface deteriorates the electrical characteristics of the film. It is considered that the formation of layers and the deterioration of the mechanical properties of the substrate are also suppressed.

The crystallinity and grain growth of the film due to the thermal effects of laser irradiation are most prominent near the surface of the irradiated film, and the effect decreases toward the interface with the substrate. That is, the thermal effect of laser irradiation has a gradient in the film thickness direction. Specifically, the surface side force of the microcrystalline ceramic film can also generate a temperature gradient that decreases in the thickness direction in the range of 1 ° CZm to 100 ° CZm toward the metal substrate. Therefore, the temperature near the interface with the substrate is extremely low as compared with the surface layer of the film, so that melting and deformation, surface oxidation, and deterioration of mechanical properties due to the thermal influence of the substrate can be suppressed. Further, by suppressing the formation of a hetero phase composed of an interdiffusion layer at the interface between the film and the substrate, it is possible to prevent the film from being misaligned. In addition, Since the phase is often a low dielectric constant layer, it is possible to prevent the dielectric properties of the high dielectric constant film from deteriorating due to a series circuit with the high dielectric constant layer. In the conventional furnace annealing method, a large structure has a temperature gradient inside, but a film structure heats up the entire structure. As a result, a different phase between the film and the substrate interface also grows.

 Fig. 10 shows the PZT film formed directly on the stainless steel substrate, close to the substrate side PZT film and the surface! 2 shows a cross-sectional transmission electron microscope image (upper figure) and an electron diffraction image (lower figure) of the internal PZT film. As a result, the crystal size of the internal PZT film near the surface is larger than that of the substrate-side PZT film, and the electron diffraction image showing crystallinity does not include a halo-like broad component showing microcrystals (amorphous). It can be seen that it shows a perfect ring. In other words, the crystallinity of the internal PZT film is improved more than the PZT film on the substrate side, that is, the crystal grain size grows.Specifically, the crystal grain size near the film surface is 1000 nm, and the vicinity of the interface with the substrate is near. The crystal grain size lOnm and the gradient distribution are formed. Since the crystal grain size distribution has a gradient, the stress in the film is reduced (dispersed and relaxed), and thus the separation of the film and the deterioration of film characteristics such as electrical characteristics caused by the stress can be prevented. In addition, it is possible to achieve both the mechanical strength of the film due to the fine grain size and the electrical characteristics of the film due to the grain growth. In addition, the introduction of crystallographic pressure at the interface between particles of different particle sizes causes the crystal lattice of the film to be distorted, resulting in very high temperatures that exceed those of the electric furnace annealed film and sintered body. It is expected that a large physical property value, for example, a physical property value such as a giant dielectric constant will be exhibited.

 FIG. 11 shows cross-sectional transmission microscope images of an electric furnace annealing and a laser annealing of a PZT film directly formed on a stainless steel substrate. Since the thermal effect of laser irradiation has a gradient in the film thickness direction, it is possible to reduce the thickness of the hetero-phase, which is the force of the interdiffusion layer formed at the interface between the film and the substrate. Moreover, at this time, the adhesion between the film and the substrate is maintained. Specifically, the thickness of the hetero phase can be suppressed to the range of lnm-200nm.

Actually, when the present invention was applied to a PZT film with a thickness of 35 nm formed on a stainless steel foil substrate with a thickness of lOO nm, the crystal grain size was 40-60 η m and the phase was different in the case of the conventional electric furnace. Thickness is 250nm, laser irradiation is 30 ~ 5 crystal grain size Onm, the thickness of the foreign phase was 100 nm. Moreover, the electrical properties were superior to those obtained by heating the electric furnace, although the average crystal grain size of the laser-irradiated film was smaller than that obtained by heating the electric furnace, that is, the mechanical strength was increased. Actually, as a result of measuring the ferroelectricity, the remanent polarization value and the coercive electric field value were CZcm2 and 50 kVZcm for the electric heating furnace, and CZcm2 and 30 kVZcm for the laser irradiation, respectively. The rate and dielectric loss were 680.7% in the case of electric furnace heating and 130.5% in the case of laser irradiation, respectively, at a frequency of 1 kHz.

抗電界が 47. 6kV/c mの膜を直接 SUS430ステンレス基板上で得ることができた。すなわち、赤外線レー ザ一照射による特性改善の効果は成膜中の照射だけでは得られず、成膜後の照射 によって初めて得られた。 The PZT film is formed on a SUS430 stainless steel substrate reciprocating at a scanning speed of 0.3125 mmZs with an aerosol jet with an oxygen flow rate of 6 lZmin and an infrared laser with a power of 10 W and a beam diameter of 4 mm for 5 minutes while irradiating with an aerosol jet. Only the substrate was stopped, and the heat treatment was performed for about 3 minutes under the low gas pressure of 5 Pa or less while keeping the scanning speed of the substrate and the infrared laser irradiation conditions unchanged. As a result, irradiation of the infrared laser at the time of film formation had no effect on the film having a film thickness of 15111, but the irradiation of the infrared laser after the film formation showed a residual effect as shown in Fig. 9. Polarization value of 28.4 μ

A film with a coercive electric field of 47.6 kV / cm was obtained directly on a SUS430 stainless steel substrate. In other words, the effect of improving properties by infrared laser irradiation was not obtained only by irradiation during film formation, but was first obtained by irradiation after film formation.

Industrial applicability

 The present invention relates to the formation of a ceramic ultrafine particle film in which a dense and crystallized film is irradiated with a laser to promote grain growth of the film and to improve electrical and electromechanical characteristics. Applications include high-speed optical scanners, key components of next-generation display devices such as next-generation inkjet printers and laser displays, and retinal projection displays, high-speed actuators for nanopositioning, and micro ultrasonic devices. Can be. In addition, applications in the fields of high-frequency circuit components used in next-generation mobile terminals, microelectromechanical systems (MEMS, NEMS), and microchemical analysis systems (-TAS) can be expected.

Claims

The scope of the claims  [1] A method for forming a ceramic film structure, comprising: after forming a microcrystalline ceramic film on a metal substrate, irradiating the microcrystalline ceramic film with an infrared laser.  [2] Surface temperature of microcrystalline ceramic film by infrared laser irradiation Maintains a temperature gradient that decreases from 1 ° CZm to 100 ° CZm in the film thickness direction toward the metal substrate. 2. The method for forming a ceramic film structure according to claim 1, wherein:  3. The method for forming a ceramic film structure according to claim 1, wherein a microcrystalline ceramic film is formed on a metal substrate by an aerosol deposition method.  [4] The amount of heat input per unit area to the microcrystalline ceramic film by the irradiation of the infrared laser, and the difference in the coefficient of thermal expansion between the metal substrate and the microcrystalline ceramic film, the microcrystalline ceramic film formed on the metal substrate The method for forming a ceramic film structure according to any one of claims 1 to 3, wherein upper limits of the thickness and the film area are set.  [5] The method for forming a ceramic film structure according to claim 4, wherein the microcrystalline ceramic film is formed by lamination. [6] The microcrystalline ceramic film as a lead zirconate titanate, if the amount of heat input per unit area of the P ZT film by the irradiation of infrared laser is 10j / mm ² or more, the membrane area of the lead zirconate titanate film method of forming a ceramic film structure paragraph 5, wherein the range of paragraph 4, wherein the range of billed characterized by 100 mm ² below or thickness less 20 m.  [7] Heat input by infrared laser irradiation is controlled by the amount of heat input per unit area of the microcrystalline ceramic film, laser beam diameter, and irradiation time, and is controlled so that the temperature is gradually decreased by laser heating after laser irradiation. The method for forming a ceramic film structure according to any one of claims 1 to 3, characterized in that:  [8] The method for forming a ceramic film structure according to claim 7, wherein the temperature is controlled to be 300 ° CZh or less until the temperature of the film becomes 300 ° C or less. [9] According to a method of forming a ceramic film structure, a microcrystalline ceramic film is formed on a metal substrate. A method for forming a ceramic film structure, comprising: irradiating an infrared laser during film formation to form a film; and irradiating the film with an infrared laser in a low gas pressure atmosphere after the film is formed. Method of forming a ceramic film structures ranging ninth claim of claim, which is a lkPa - [10] a low gas pressure atmosphere 1 X 10- ^6.  [11] The method according to claim 9, wherein, during the irradiation with the infrared laser in a low gas pressure atmosphere after the film formation, the separation of the film from the substrate is detected by a visible light laser different from the infrared laser. 11. The method for forming a ceramic film structure according to claim 10 or claim 10.  [12] A movable substrate holder for fixing the metal substrate is provided, a nozzle for injecting the aerosol of the ceramics is provided on the surface of the metal substrate, and an infrared laser oscillator and an optical system are provided. An apparatus for forming a ceramic film structure, characterized in that the irradiated infrared laser is applied to a microcrystalline ceramic film crystallized on a metal substrate via an optical system. 13. The apparatus for forming a ceramics film structure according to claim 12, wherein the substrate holder is rotatable. [14] The claim 12 or claim, characterized in that an aerosol jet using a reactive gas such as oxygen and nitrogen is jetted from the nozzle onto the oxidized ceramics and the nitrided ceramics. 14. The apparatus for forming a ceramic film structure according to claim 13. [15] The optical system is equipped with a collimator and lens, and when the infrared laser is driven over a wide range by a mirror, the power and beam diameter of the infrared laser are controlled so that the heat input to the film is always the same. The apparatus for forming a ceramic film structure according to any one of claims 12 to 14, wherein: [16] The apparatus for forming a ceramic film structure according to any one of claims 12 to 15, wherein a heating means for heating the carrier gas of the aerosol and the metal substrate is provided. .  [17] The method according to any one of claims 12 to 16, wherein a means for controlling the degree of heating of the ceramic film according to the thermal conductivity of the metal substrate is provided. An apparatus for forming the ceramic film structure according to the above. [18] at least a metal substrate having a thermal expansion coefficient is a combination of the following substrates 30 X 10- ⁶ Z ° C The apparatus for forming a ceramic film structure according to any one of claims 12 to 17, wherein a ceramic film structure is used. [19] The ceramic film according to any one of claims 12 to 18, wherein a metal substrate obtained by combining at least a substrate having a thermal conductivity of 450 WZmK or less is used. An apparatus for forming a structure. [20] The first aspect of the present invention wherein a metal substrate having a thickness of at least 100 / zm is used. 20. The apparatus for forming a ceramic film structure according to any one of claims 2 to 19.  [21] The ceramic film structure according to any one of claims 12 to 20, wherein a metal substrate obtained by combining a substrate having a Young's modulus of at least 500 GPa is used. Body shaping device. [22] The apparatus for forming a ceramic film structure according to any one of claims 12 to 17, wherein SUS430 is used as the metal substrate. [23] the thermal expansion coefficient of less 30 X 10- ⁶ Z ° C, the thermal conductivity is 450WZmK less and the Young's modulus A microcrystalline ceramic film is formed on a metal substrate with a thickness of 110 μm, which is a combination of substrates of 500 GPa or less, and the microcrystalline ceramic film is manufactured by irradiating an infrared laser. Ceramic film structure. 24. The ceramic film structure according to claim 23, wherein the metal substrate is SUS430.  25. The ceramic film structure according to claim 23 or claim 24, wherein the material composition of the microcrystalline ceramic film is mainly composed of lead zirconate titanate.  [26] The ceramic film structure according to any one of claims 23 to 25, wherein the thickness of the microcrystalline ceramic film is 0.1-20 / zm. body.  [27] The claim 23 to claim, wherein the crystal grain size of the microcrystalline ceramic film is inclinedly distributed so as to decrease toward the vicinity of the film surface and the vicinity of the interface with the metal substrate. 27. The ceramic film structure according to any one of the items 26 to 26. 28. The method according to claim 23, wherein the thickness of the interdiffusion layer formed at the interface between the microcrystalline ceramic film and the metal substrate is in the range of 1 nm to 200 nm. Item 2. The ceramic film structure according to Item 1.