JPH08296035A - Formation of thin film using laser-beam abrasion - Google Patents

Abstract

PURPOSE: To provide a method for easily forming a soft magnetic thin film at low temp. on a large area by laser beam abrasion. CONSTITUTION: A product jetted from a target 8 by the irradiation with a pulsed first laser beam 2 is allowed to fly in an oxidizing gas at 10-500mTorr or deposited on a substrate 11, these are respectively irradiated with a high- speed second laser beam 20 or the gas is blown against the substrate, and a flying magnetic substance particle is captured by a magnetic field. Besides, the target 8 is irradiated with the first laser beam 2 with the scanning width changed, the deposition position on the substrate 11 is changed and hence the irradiation position of the second laser beam 20 is moved, or the product is deposited on the substrate moving in the magnetic field to form a soft magnetic thin film good in crystallinity is formed on a large area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming method using laser ablation used for manufacturing a magnetic thin film.

[0002]

2. Description of the Related Art A conventional method for manufacturing a magnetic thin film will be described below. High-frequency magnetron sputtering is generally used to form a magnetic thin film, and it is widely used for manufacturing amorphous magnetic thin films, permalloy thin films, sendust thin films, and the like. Also, in the production of ferrite magnetic thin films, a high frequency sputtering method has been tried. For example, Chen, Tsujimoto, Shirae, etc. have published in the Institute of Electrical Engineers of Japan, Magnetics Research Group material MAG-88-120, p. 49 (1988). The outline of this sputtering apparatus will be described with reference to FIG. In the vacuum chamber 51, a substrate platform 52 and a target platform 54 electrically insulated from the vacuum chamber 51 by an insulator 53 are attached, and a gas introduction port 55 is installed.
When Ar is introduced into the vacuum chamber 51 and the inside of the vacuum chamber 51 is maintained at 1 to 10 mTorr by the exhaust board 56 and high frequency power is applied to the target table 54 by the power source 57, plasma 58 is generated between the substrate table 52 and the target table 54. To do. In this state, when the target 59, which is a raw material of the magnetic thin film, is placed on the target table 54, the plasma 58
The ions inside hit the surface of the target 59, a sputtering phenomenon occurs, and a thin film 60 is formed on the substrate table 52.

[0003]

However, in the above conventional structure, the kinetic energy of atoms and molecules flying from the target (for example, Ni-Zn-ferrite) is small, and the pressure of the reactive gas that can be introduced is also small. ,
When the surface temperature of the substrate table 52 is low, for example, 450 ° C. or lower, the thin film 60 becomes an amorphous or a polycrystalline thin film with low orientation, and the thin film does not have a spinel-type crystal structure peculiar to ferrite. There was a problem that the characteristics did not reach the practical level. For this, 500 ° C
Attempts have been made to improve the soft magnetic characteristics by performing the above substrate heating, annealing at 1000 ° C. or higher, and the like. Furthermore, it is difficult for the sputtering method to accurately control the composition ratio of three or more elements. Therefore, the thin film formed by the sputtering method has poor soft magnetic properties for application to a device, cannot be applied to a substrate having a low heat resistance temperature, and is still in a difficult state for practical use. It was also found that there is a problem that granular or flaky particles are mixed in the thin film.

The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a thin film forming method using laser ablation for easily forming a soft magnetic thin film in a large area at low temperature.

[0005]

To achieve this object, a thin film forming method using laser ablation according to the first aspect of the present invention is characterized in that a target and a substrate are provided in an oxidizing gas atmosphere in a vacuum chamber. The target is irradiated with the first laser light to generate the constituent elements of the target, and the product that is flying or is deposited on the substrate is irradiated with the second laser light.

In the above structure, the wavelength of the second laser light is preferably 500 nm or less. Further, the oxidizing gas is preferably O ₂ , N ₂ O or NO ₂ . Also, the intensity of the second laser light with which the substrate is irradiated is 0.0.
It is preferably 01 J / cm ² or more and 1.0 J / cm ² or less.

In the thin film forming method using the second laser ablation of the present invention, the target provided in the vacuum chamber is irradiated with the first laser beam to generate the constituent elements of the target, and the target element is produced during flight or The product deposited on the substrate is irradiated with pulsed laser light or continuous light having a higher irradiation repetition rate than the first laser light as the second laser light.

In the thin film forming method using laser ablation according to the third aspect of the present invention, the target provided in the vacuum chamber is irradiated with the first laser light to generate the constituent elements of the target, and the first element is formed. The product is deposited by the first laser light by moving the position where the product is deposited on the substrate by scanning the laser light and irradiating the product that is flying or is deposited on the substrate with the second laser light. The scanning is performed following the movement of the area.

According to the fourth method for forming a thin film using laser ablation of the present invention, a target provided in a vacuum chamber is irradiated with laser light having a variable scanning width, and a product from the target is deposited on a substrate. It is to be deposited.

In the above structure, it is preferable that at least the substrate is moved and the laser beam is scanned in a uniaxial direction, and the moving direction of the substrate does not coincide with the scanning direction. Further, it is preferable that the substrate and the target do not move and the surface of the target is scanned with the laser light.

In the thin film forming method using laser ablation according to the fifth aspect of the present invention, a target containing an element constituting a magnetic material is provided in a vacuum chamber, and lines of magnetic force are arced between the target and the substrate. On the substrate that is provided with such a magnetic field generation source, irradiates the target with pulsed laser light so that the constituent components generated from the target pass through a specific position of the magnetic force line, and moves in a certain direction in the magnetic force line. The product is deposited on.

According to the sixth method for forming a thin film using laser ablation of the present invention, a target containing an element constituting a magnetic material is provided in a vacuum chamber so that a magnetic field is constant in a magnetic force line generated from a magnetic field source. A substrate is provided on the substrate, the target is irradiated with laser light to generate constituent components of the target, and the product is deposited on the substrate while moving or rotating the substrate relative to the irradiation position of the laser light. It is what makes me.

According to a seventh method of forming a thin film using laser ablation of the present invention, a target containing an element constituting a magnetic material is provided in a vacuum chamber, and the target is irradiated with pulsed laser light to produce a target of the target. A component is generated, a magnetic field generation source is provided between the target and the substrate so as to surround the product, and the product passed through the magnetic field generation source is deposited on the substrate.

In the eighth thin film forming method using laser ablation of the present invention, a pulse is applied to a target in a vacuum chamber.
By irradiating a laser beam to generate the constituent components of the target, depositing the product on the substrate, and at the same time, injecting a gas that does not generate a reactant other than the target in a pulsed manner on the product deposited on the substrate. is there.

According to a ninth method for forming a thin film using laser ablation of the present invention, a target in a vacuum chamber is irradiated with a first laser beam to generate constituent elements of the target, and a product in flight is produced. The second laser light is irradiated, and the product deposited on the substrate is irradiated with the third laser light.

According to a tenth method of forming a thin film using laser ablation of the present invention, a target in a vacuum chamber is irradiated with a first laser beam to generate constituent elements of the target, which are deposited in flight and on a substrate. At least one of the products thus formed is irradiated with ultraviolet light, and the product deposited on the substrate is
The laser light is emitted.

In the above structure, the target contains an element constituting a magnetic material, and after forming a thin film on the substrate,
It is preferable to anneal at 250 ° C. or higher for 30 minutes or longer.

[0018]

With this structure, the product ejected from the target by the irradiation of the first laser light is made to fly in the oxidizing gas or is deposited on the substrate, and at the same time, the product is irradiated with the second laser light to oxidize the product. A thin film having good crystallinity can be formed at a low substrate temperature by promoting reaction and migration. The higher the frequency of irradiation with the second laser light, the better the crystallinity of the thin film. Further, by blowing gas onto the substrate or capturing magnetic particles in flight with a magnetic field, it is possible to prevent particles from being mixed into the thin film and form a high-quality thin film.

Further, by irradiating the target with the laser beam for ablation while changing the scanning width, moving the deposition position on the substrate, and following it, the irradiation position of the annealing laser beam is moved efficiently and greatly. A thin film with good crystallinity can be formed in the area. This method can also be applied to film formation in a magnetic field, which is effective in forming a soft magnetic thin film.

[0020]

【Example】

(Embodiment 1) A first embodiment of a thin film forming method using laser ablation according to the present invention will be described with reference to FIG. 1A is a front view and FIG. 1B is a side view thereof.

In FIG. 1, reference numeral 1 denotes an ablation pulse for oscillating a pulsed ablation laser beam.
A laser oscillator, 2 is a first laser beam which is a pulse laser beam for ablation, 3 is a vacuum chamber, 4 is a vacuum pump, 5 is a moving mechanism of the pulse laser oscillator for ablation 1, 6 is a reflecting mirror, and 7 is Condensing lens, 8 is Ni, Zn
And a ferrite solid target containing at least one of Mn (hereinafter referred to as a target), 9 is a target holder, 10 is a plume, 11 is a substrate, 12 is a substrate holder,
Reference numeral 13 is a permanent magnet, 14 is a magnetic field generation source, 15 is a gas ejection tube, 16 is a linear introduction machine, 17 is a laser oscillator for annealing, 18 is a moving mechanism of the laser oscillator for annealing 17, 1
Reference numeral 9 is a lens, 20 is a second laser beam, and 24 is an introduction window.

First laser emitted from the pulse laser oscillator 1
When the target 8 in the vacuum chamber 3 is irradiated with the laser light 2 of 1., the product becomes a plume 10 that emits bright light and is ejected, and the product is deposited on the substrate 11 to form a thin film. By irradiating the product that is flying or deposited on the substrate with the second laser light 20 for annealing, the oxidation reaction and the migration of the deposit on the substrate 11 are promoted, and a thin film with good crystallinity is formed. A gas pressure of 10 to 500 mTorr, which has a relatively high pressure, is suitable in order to cause a sufficient oxidation reaction and not reduce the kinetic energy of the product.
If the wavelength of the second laser light is set to 500 nm or less,
Owing to the large light energy of the laser light, the oxidation reaction and migration are promoted. O ₂ , N as oxidizing gas
_{If 2} O and NO ₂ are used, 180 nm and 200 n, respectively
Since the dissociation becomes large with respect to light having a wavelength of m or 400 nm or less, the oxidation reaction is actively carried out. The laser intensity that improves the crystallinity and does not damage the deposit is 0.001 to 1.0 J / cm ² .

Further, in FIG. 1, the second laser light 20 for annealing is more effective in improving the crystallinity when the pulse irradiation speed is higher. That is, irradiation may be performed faster than the first laser light 2 for ablation, or continuous light may be used.

Further, in FIG. 1, in order to form a film on a large area, the moving mechanism 5 of the pulse laser oscillator is moved in a direction perpendicular to the paper surface to move the deposition position of the product and follow the movement of the deposition. As described above, by moving the moving mechanism 18 of the annealing laser oscillator in the direction of the arrow in the figure, wide width annealing can be performed.

Further, in FIG. 1, the scanning width of the laser beam 2 for ablation on the target 8 is made variable so as to be continuous in a zigzag shape or a substantially rectangular pulse shape as in the case of the disk-shaped target 21 shown in FIG. Scanning increases the efficiency of use of the laser light 2. The same effect is obtained even when the substrate has a disk shape. In FIG. 1, the target 8 and the substrate 11 are moved in the direction of the arrow by the straight line introducing device 16, so that a thin film can be efficiently formed in a large area by scanning the laser beam for ablation in a direction that does not match these moving directions. Alternatively, when the target 8 and the substrate 11 are fixed, the first laser beam 2 for ablation may be scanned within the target plane. Particularly when the magnetic thin film is formed in a magnetic field, the permanent magnets 13 are provided in parallel,
A thin film can be formed in a large area by depositing the product from the target 8 on the substrate 11 in the magnetic force lines while passing the substrate 11 through the arc-shaped magnetic force lines.

Granular or flaky particles are mixed in the thin film. These are generated by spraying a gas, which does not generate a reaction product other than the intended one, from the gas ejection pipe 15 onto the product deposited on the substrate in a pulsed manner. The particles can be removed without slowing the formation rate of. When the target 8 contains an element that constitutes a magnetic material, a magnetic field generation source 14 is provided during the flight of the product, and this is used to capture the particulate magnetic material in flight,
It is possible to prevent them from being mixed in the thin film.

Further, the formed thin film is kept at 250 ° C. or higher for 3 hours.
By annealing for 0 minutes or more, the coercive force decreases, the saturation magnetic flux density increases, and the soft magnetic characteristics are improved. Especially when annealed at 400 ° C or higher for 60 minutes or longer, the coercive force is 10
Saturation magnetic flux density is 1500 gauss below Oersted
s or more, the effect is remarkable.

(Embodiment 2) A second embodiment of the thin film forming method using laser ablation of the present invention will be described with reference to FIG. In FIG. 3, the first point different from the first embodiment is that the beam is emitted in the middle of the optical path of the second laser light 20.
The splitter 22 is provided to irradiate the laser light both during the flight of the product from the target and after the deposition on the substrate. By irradiating both with laser light, the promotion of oxidation reaction and migration can be further enhanced, and the crystallinity of the formed thin film can be further enhanced.

In FIG. 3, a second embodiment different from the first embodiment is used.
The point is that the substrate 11 and the permanent magnet 13 are fixed to the support 12 and the support is rotated by the rotating mechanism 23 to form a thin film. As a result, a thin film can be formed in a large area while keeping the magnetic force acting on the substrate 11 constant. Further, the substrate may move relative to the laser irradiation position. Other than this fixing method, another method such as rotating in synchronization may be used as long as the relative position between the substrate 11 and the permanent magnet 13 can be kept constant.

(Embodiment 3) A third embodiment of the thin film forming method using laser ablation of the present invention will be described with reference to FIG. In FIG. 4, the difference from the first or second embodiment is that at least one of the products in flight and the product deposited on the substrate is irradiated with ultraviolet light 26 from an ultraviolet lamp 25,
The point is that the laser beam 20 is irradiated onto the deposit on the substrate 11. The ultraviolet light 26 accelerates the oxidation reaction, and the laser light 20 is used for heating the deposit, thereby
A costly laser beam can be effectively used.
The source of the ultraviolet light 26 may be another means such as an excimer lamp.

[0031]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, the product ejected from the target by the irradiation of the first laser light for ablation is caused to fly in the oxidizing gas or is deposited on the substrate, and the product is annealed. By irradiating with the second laser light, an oxidation reaction and migration are promoted, and a soft magnetic thin film having good crystallinity can be easily formed in a large area at a low substrate temperature. In addition, the crystallinity of the thin film can be improved as the frequency of irradiation of the second laser light is higher.

Further, by blowing gas onto the substrate or trapping magnetic particles of magnetic particles in flight with a magnetic field, it is possible to prevent the particles from being mixed into the thin film and form a high quality thin film.

Further, by irradiating the target with the first laser light while changing the scanning width, moving the deposition position on the substrate, and following the movement of the irradiation position of the second laser light, the efficiency can be improved. A thin film with good crystallinity can be formed in a large area. This method can also be applied to film formation in a magnetic field, which is effective in forming a soft magnetic thin film.

[Brief description of drawings]

FIG. 1A is a configuration diagram showing a first embodiment of a thin film forming method using laser ablation of the present invention, and FIG. 1B is a first embodiment of a thin film forming method using laser ablation of the present invention. Configuration diagram showing an embodiment

FIG. 2 is a diagram showing a scanning trajectory of laser light on a cylindrical target in the first embodiment.

FIG. 3 is a configuration diagram showing a second embodiment of a thin film forming method using laser ablation of the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of a thin film forming method using laser ablation of the present invention.

FIG. 5 is a configuration diagram of a sputtering apparatus in a conventional method of manufacturing a magnetic thin film.

[Explanation of symbols]

 1 pulse laser oscillator 2 first laser beam 3 vacuum chamber 4 vacuum pump 5 moving mechanism 6 reflecting mirror 7 condenser lens 8 target 9 target holder 10 plume 11 substrate 12 substrate holder 13 permanent magnet 14 magnetic field source 15 gas Ejection tube 16 Straight line introducer 17 Laser oscillator 18 Moving mechanism 19 Second lens 20 Laser light 21 Cylindrical target 22 Beam splitter 23 Rotating mechanism 24 Introduction window 25 Ultraviolet lamp 26 Ultraviolet light

Front Page Continuation (72) Inventor Kansuke Mikami 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (16)

[Claims] 1. A target and a substrate are provided in an oxidizing gas atmosphere in a vacuum chamber, and the target is irradiated with a first laser beam to generate constituent elements of the target, which are deposited in flight or on the substrate. A method for forming a thin film using laser ablation, which comprises irradiating a second laser beam to the produced product. 2. The thin film forming method using laser ablation according to claim 1, wherein the wavelength of the second laser light is 500 nm or less. 3. The method of forming a thin film using laser ablation according to claim ₂ , wherein the oxidizing gas is O ₂ , N ₂ O or NO ₂ . 4. The intensity of the second laser light is 0.001 J / c.
The method for forming a thin film using laser ablation according to claim 1 or 2, wherein m ² or more and 1.0 J / cm ² or less. 5. A target provided in a vacuum chamber is irradiated with pulsed laser light as a first laser light to generate constituent elements of the target, and the constituents of the target in flight are deposited with respect to the product. A thin film forming method using laser ablation, wherein pulsed laser light or continuous light having an irradiation repetition rate faster than that of the first laser light is irradiated as the second laser light. 6. A target provided in a vacuum chamber is irradiated with a first laser beam to generate constituent elements of the target,
By scanning the first laser light, the position where the product is deposited on the substrate is moved, and the second laser light that irradiates the product that is flying or is deposited on the substrate is irradiated with the first laser light. A thin film forming method using laser ablation, which is characterized in that scanning is performed following the movement of a deposition area of a product by. 7. A thin film formation using laser ablation, characterized in that a target provided in a vacuum chamber is irradiated with laser light having a variable scanning width to deposit a product from the target on a substrate. Law. 8. The laser according to claim 7, wherein at least the substrate is moved, the laser light is scanned in one axis direction, and the moving direction of the substrate and the scanning direction do not coincide with each other.
Thin film formation method using ablation. 9. The method for forming a thin film using laser ablation according to claim 7, wherein the substrate and the target do not move and the surface of the target is scanned with laser light. 10. A substrate and a target containing an element constituting a magnetic substance are provided in a vacuum chamber, and a magnetic field generation source is provided between the target and the substrate so that magnetic lines of force are arcuate. The target is irradiated with a pulsed laser beam so that constituent components to be generated pass through a specific position of the magnetic force line, and the product is deposited on the substrate moving in a constant direction in the magnetic force line. Thin film formation method using laser ablation. 11. A target containing an element constituting a magnetic body is provided in a vacuum chamber, a substrate is provided so that a magnetic field is constant in magnetic lines of force generated from a magnetic field source, and the target is irradiated with pulsed laser light. Using the laser ablation, wherein the constituent components of the target are generated and the product is deposited on the substrate while moving or rotating the substrate relative to the irradiation position of the laser light. Thin film formation method. 12. A target containing an element constituting a magnetic material is provided in a vacuum chamber, the target is irradiated with pulsed laser light to generate constituent components of the target, and the product is surrounded so as to surround the target. A laser, characterized in that a magnetic field generation source is provided between the target and the substrate, and the product that has passed through the magnetic field generation source is deposited on the substrate.
Thin film formation method using ablation. 13. A target in a vacuum chamber is irradiated with pulsed laser light to generate constituent components of the target, and these products are deposited on a substrate, and at the same time, a gas that does not generate a reactant other than the intended one is generated on the substrate. A method for forming a thin film using laser ablation, characterized in that the product deposited on the substrate is sprayed in a pulse shape. 14. A target provided in a vacuum chamber is irradiated with a first laser beam to generate constituent elements of the target, and a product in flight is irradiated with a second laser beam to be deposited on a substrate. A thin film forming method using laser ablation, wherein the product is irradiated with a third laser beam. 15. A pulse is applied to a target provided in the vacuum chamber.
Irradiating a laser beam to generate the constituent elements of the target, irradiating at least one of the product in flight and the product deposited on the substrate with ultraviolet light, and applying a second laser beam to the product deposited on the substrate. A thin film forming method using laser ablation characterized by irradiation. 16. The target according to claim 1, wherein the target contains an element constituting a magnetic substance, and after forming a thin film on a substrate, annealing is performed at 250 ° C. or higher for 30 minutes or more. Thin film formation method using laser ablation of.