JP3481215B2 - Laser heating apparatus and laser heating method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser heating apparatus and a laser heating method capable of measuring a magnetic field change caused by a heating state with a SQUID in order to grasp the heating state of an object.

[0002]

2. Description of the Related Art Conventionally, most laser heating treatments are performed by irradiating a laser beam with a preset output. It is possible to control the output of the laser beam while checking the condition of the object to be heated after heating. The current situation is that it is not available.

[0003]

In the conventional laser heating apparatus, since heating is performed with a constant irradiation output, there is a problem that heating can be adjusted only by the irradiation frequency. Therefore, for example, when laser welding is performed, the thermal resistance varies depending on the quality of contact between the objects to be welded.If the output value is not optimal, the temperature of the welded part rises too much and holes are opened. On the other hand, if the welding temperature is low, welding is insufficient and sufficient welding strength cannot be obtained. Further, since the reflectance of the laser beam varies depending on the surface shape and the surface roughness of the object to be heated, there is a problem that the temperature rise varies depending on the place and stable welding processing cannot be performed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a laser heating apparatus and a laser heating method capable of adjusting the output of laser light during heat treatment.

[0005]

The technical means of the present invention for solving the above problems is a laser heating apparatus provided with a heating means for outputting a laser beam to heat an object to be heated. When a stage that supports the heating target capable of irradiating laser light, a magnetic field generating unit that generates a magnetic field for the heating target supported by the stage, and the heating target is being heated by the heating unit A SQUID magnetic field detection means for detecting a heating magnetic field change that occurs with a SQUID, and an object generated by the structural change or phase change of the heating target object by heating from a magnetic signal related to the heating magnetic field change detected by the SQUID magnetic field detection unit. An object magnetic field change extraction means for extracting a magnetic field change, and an output control of laser light of the heating means are performed based on the extracted object magnetic field change. And a configuration in which an earthenware pots output control means. The structural change due to the heating of the heated object is measured with high accuracy using the SQUID, and the output of the laser light is controlled while grasping the heating state of the heated object based on the magnetic signal detected by the SQUID. Also, the upper Symbol magnetic field generating means, constituted by a coil. A magnetic field is easily generated by passing an alternating current of a predetermined frequency through the coil. Change
In the upper Symbol magnetic field generating means is constituted by a cancel coil to produce a magnetic field that cancels the magnetic field generated by the coil. Even if a high magnetic field that cannot be measured is generated by the SQUID in order to increase the measurement sensitivity, only the minute magnetic field change is detected by the SQUID.

[0006] was even or upper Symbol heating object, when it is a semiconductor, the magnetic field generating means, and configured to include a magnetic field excitation laser for exciting a magnetic field on the semiconductor surface.
When the object to be heated is a semiconductor, it is difficult to detect changes in the magnetic field even if a magnetic field is externally applied. Therefore, the change in the magnetic field in the semiconductor is detected by utilizing the characteristic that a magnetic field is generated from the semiconductor surface when the semiconductor surface is irradiated with a laser. Also, the upper SL output control means, based on the object field change in the extracted and configured with a function of controlling the optimum annealing temperature. When the annealing treatment is performed to eliminate the unevenness on the metal surface or the unevenness generated on the semiconductor surface when ions are implanted into the semiconductor, the semiconductor surface is controlled to an optimum annealing temperature. Furthermore, if necessary, the object magnetic field change extraction means is configured to include an amplitude extraction unit that extracts the amplitude of the magnetic signal. The laser light output is adjusted based on the change in the amplitude of the magnetic signal. Furthermore, if necessary, the object magnetic field change extraction means is configured to include a phase change extraction unit that extracts a phase change of the magnetic signal. The laser light output is adjusted based on the change in the phase of the magnetic signal. In addition, the SQUID magnetic field detecting means includes a differential SQUID, if necessary. Avoid adding noise due to geomagnetism to magnetic signals. Further, a magnetic shield for shielding at least the object to be heated and the SQUID magnetic field detecting means from an external magnetic field is provided as necessary. Avoid adding noise to the magnetic signal due to objects in the vicinity of the device.

Another technical means of the present invention is a laser heating method for heating an object to be heated with laser light,
Using the laser heating device, the object to be heated is supported so that it can be irradiated with laser light, and a magnetic field is applied to the object to be heated,
The object to be heated is irradiated with the laser light, and the change in the magnetic field generated when the object to be heated is heated is detected by the SQUID. The structural change due to the heating of the object to be heated is detected with high accuracy by SQUID. Also, when the upper Symbol laser beam is irradiated to the object to be heated, and a configuration in which adjustment of the output of laser light based on the magnetic field variation detected in the SQUID. The output of the laser light is adjusted based on the magnetic signal detected by the SQUID, and heating can be adjusted.

[0008]

DETAILED DESCRIPTION OF THE INVENTION A laser heating apparatus and a laser heating method according to an embodiment of the present invention will be described below with reference to the accompanying drawings. Since the laser heating method according to the embodiment is realized by the laser heating device according to the embodiment, it will be described in the description of the operation of this device. As shown in FIG. 1, the laser heating device S includes a heating unit 1
A stage 2 for supporting the heating target T capable of irradiating laser light; a magnetic field generating means 10 for generating a magnetic field for the heating target T supported on the stage 2; Squid magnetic field detection means 20 for detecting a heating magnetic field change generated while being heated with a SQUID,
An object magnetic field change extraction means 30 for extracting an object magnetic field change caused by a structural change or a phase change of the heating object T by heating from a magnetic signal related to the heating magnetic field change detected by the SQUID magnetic field detection means 20, and And the output control means 40 for controlling the output of the laser light of the heating means 1 based on the change of the magnetic field of the object. Heating means 1
Is equipped with a light source capable of emitting high-energy laser light for heating the heating target T. The stage 2 is provided with a mechanism for fixing the heating target T and allowing three-dimensional displacement, and allows the heating target T to be moved arbitrarily. Specifically, the magnetic field generating means 10 is configured to include a coil c and a canceling coil c ′ that generates a magnetic field that cancels the magnetic field generated by the coil c, as shown in FIG. An AC signal having a predetermined frequency is supplied from the transmission source 11 to the coil c and the cancel coil c ′.

The SQUID magnetic field detecting means 20 senses a SQUID ring biased with a constant current and a pickup coil for sensing and transmitting the magnetic flux to the SQUID ring and a feedback coil for feeding back the magnetic flux so that a constant current flows through the SQUID ring. (Not shown) and a dude portion 21 having a dual for holding them at a low temperature, and a magnetic flux lock portion 22 for controlling the feedback amount of the magnetic flux and outputting it as a magnetic signal. Further, although not shown, a shield for protecting the heating target T and the SQUID magnetic field detecting means 20 from an external magnetic field is provided. The measurement accuracy of the magnetic field change using the SQUID has the highest sensitivity among existing magnetic sensors, and it is possible to detect a weak magnetic field of about 10 fT. Since noise such as geomagnetism can be canceled by using a gradiometer whose pickup coil is a differential type (differential type SQUID), it is easy to extract a magnetic field change due to the heating target T without an expensive magnetic shield room. . Further, when a SQUID made of a recent high-temperature superconducting material is used, cooling with liquid nitrogen becomes possible, and the cooling cost is low and easy.

The object magnetic field change extraction means 30 comprises an amplitude extraction section 31a for extracting the amplitude of the magnetic signal. The amplitude extraction unit 31a extracts a change in the amplitude of the AC signal by converting the AC signal supplied to the coil into a magnetic field and passing through the heating target T. The amplitude extraction unit 31a includes a first multiplier 32a that performs a product of a magnetic signal and an AC signal of the transmission source 11, a shifter 33 that shifts the phase of the AC signal of the transmission source 11 by π / 2, and a magnetic signal and a shifter. A second multiplier 32b that performs the product of the output signal of 33 and the first multiplier 32.
a first low-pass filter 3 for passing the low-pass of the output of a
4a, a second low pass filter 34b that passes the low band of the output of the second multiplier 32b, a first squarer 35a that squares the output of the first low pass filter 34a, and a second Second squarer 35b that squares the output of the low-pass filter 34b, and the first squarer 35a and the second squarer 3
It is composed of an adder 36 for adding the outputs of 5b and a square root 37 for taking the square root of the output of the adder 36. The amplitude extraction unit 31a extracts the amplitude of the magnetic signal (change in the magnetic field of the object) by processing the magnetic signal (change in the heating magnetic field) output from the SQUID magnetic field detection unit 20 and the AC signal of the transmission source 11. The output control unit 40 controls the output of the heating unit based on the amplitude value of the magnetic signal extracted by the supplied amplitude extraction unit 31a. The output control is performed based on the characteristic of the magnetic signal in the heating state of the heating target T that is acquired in advance.

Therefore, the heating of the object T to be heated by using the laser heating apparatus S according to this embodiment is performed according to the flow shown in FIG. The heating characteristics of the heating target T are investigated in advance. The heating characteristic is information about the change of the magnetic field according to the heating state of the heating target T, and includes the influence on the magnetic field in the molten state. The heating target T is placed on the stage 2 so that the heating spot is irradiated with laser light.
The magnetic field is applied to the heating target T. Heating target T
A laser beam having a desired output is applied to the. Irradiation with laser light can be performed continuously or intermittently. The laser light is emitted from the light source to the heating target T through the mirror m, the objective lens o, and the protective glass g. The magnetic signal at the time of laser light irradiation is sampled to examine the change in the magnetic field. The heating state of the heating target T can be grasped from the sampled magnetic signal and the heating characteristic of the heating target T. When the heating state is the desired state, the heat treatment is stopped. When the heating state is not the desired state, the laser light output control is performed and the heating process is performed until the desired state is reached.

As for the coil c and the cancel coil c'shown in FIG. 2 used in the embodiment, the coil c and the cancel coil c'can be formed as the same coil Cx as shown in FIG.

FIG. 5 shows a laser heating apparatus S according to another embodiment of the present invention. Laser heating device S
Is configured in the same manner as the laser heating apparatus S according to the embodiment, except that the object magnetic field change extraction means 30 is further provided with a phase change extraction section 31b for extracting the phase change of the magnetic signal. The phase change extraction unit 31b uses the first squarer 3
Divider 3 that divides the output of 5a by the output of the second squarer 35b
8 and the arctangent unit 39 for outputting the arctangent of the output of the divider 38
Composed of and. The phase change extraction unit 31b processes the output in the amplitude extraction unit 31a and extracts the phases of the AC signal and the magnetic signal of the transmission source 11. The output control unit 40 controls the output of the heating unit 1 based on the amplitude value of the magnetic signal extracted by the supplied amplitude extraction unit 31a and the phase difference value (change in the magnetic field of the object) extracted by the phase change extraction unit 31b. . The output control is performed based on the characteristic of the magnetic signal in the heating state of the heating target T that is acquired in advance.

FIG. 6 shows a laser heating apparatus S according to another embodiment of the present invention. The laser heating apparatus S shown here is limited to the semiconductor T as the object to be heated, and is related to the embodiment except that the magnetic field excitation means 12 uses a magnetic field excitation laser 12 for exciting a magnetic field on the semiconductor surface. It has the same structure as the laser heating device S. The magnetic field excitation laser 12 is provided with a laser light source having a photon energy larger than the band gap of the semiconductor. By irradiating the semiconductor surface with the magnetic field excitation laser 12 through the mirror m, the laser light is converted into a current in the semiconductor, and the magnetic field generated by the converted current is measured to detect the change in the magnetic field. With the magnetic field excitation laser 12,
The semiconductor surface can be annealed more effectively. For example, if the optimum annealing temperature as the heating characteristic is known, the annealing process can be performed while gradually raising the heating temperature.

[0015]

As described above, according to the laser heating apparatus of the present invention, a stage for supporting a heating target capable of irradiating laser light and a magnetic field for the heating target supported on the stage are generated. A magnetic field generation means, a SQUID magnetic field detection means for detecting a heating magnetic field change generated when the heating object is being heated by the heating means with a SQUID, and a heating object from a magnetic signal relating to the heating magnetic field change detected by the SQUID magnetic field detection means Object magnetic field change extraction means for extracting an object magnetic field change caused by structural change or phase change due to heating, and output control means for controlling laser light output of the heating means based on the extracted object magnetic field change Since it is configured by including, the output of the laser light can be adjusted while grasping the heating state of the heating target during the heat treatment. In addition, the magnetic field generating means is configured with a coil.
Therefore, the magnetic field can be easily generated. It is possible to generate a magnetic field that serves as a probe signal for measuring the change in magnetic permeability of the heated portion. Furthermore, since the magnetic field generating means is configured by including the cancel coil that generates the magnetic field that cancels the magnetic field generated by the coil, magnetic saturation of the SQUID can be avoided and the operating dynamic range can be greatly increased. Furthermore, the heating object, when it is a semiconductor, a magnetic field generating means, since it is configured provided with a magnetic field excitation laser for exciting a magnetic field on the semiconductor surface, the magnetic field change of the photocurrent of the temperature rise of the semiconductor Therefore, it is possible to eliminate the need for a coil for generating a magnetic field that requires a power supply wiring. Further, since the output control means is configured to have a function of controlling the optimum annealing temperature based on the extracted change in the magnetic field of the object, the optical state of the object to be heated and the nonuniform thermal conductivity in the vicinity thereof are obtained. Uniform annealing can be performed without being affected by the property. Furthermore, when the object magnetic field change extraction means is configured with an amplitude extraction unit that extracts the amplitude of the magnetic signal, the temperature is measured from the change in the amplitude of the magnetic signal, and thermal processing is performed at a uniform temperature. You can

Furthermore, the object magnetic field change extraction means is
When configured with a phase change extraction unit that extracts the phase change of the magnetic signal, the shape effect of the object is corrected, and it is possible to measure the temperature change rate that is difficult to capture only with the amplitude of the magnetic signal, and the sensitivity is higher. Control can be performed. Also,
When the SQUID magnetic field detection unit is configured to include a differential SQUID, it is possible to obtain a magnetic signal that is not affected by the geomagnetism. Further, when at least the object to be heated and the SQUID magnetic field detecting means are provided with a magnetic shield for shielding from an external magnetic field, a magnetic signal without the influence of magnetism generated by the peripheral substance can be obtained. According to the laser heating method of the present invention, the object to be heated is supported so that it can be irradiated with laser light, a magnetic field is applied to the object to be heated, the object to be heated is irradiated with laser light, and the object to be heated is heated. Since the change in the magnetic field is detected by the SQUID, it is possible to magnetically grasp the heating state of the object to be heated during the heat treatment. In addition, because the laser light output is adjusted based on the change in the magnetic field detected by the SQUID while the laser light is being applied to the object to be heated, the heating state of the object to be heated can be grasped magnetically to adjust the heating. Can be done.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a laser heating device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a cancel coil used in the laser heating device according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing processing steps of a laser heating method according to an embodiment of the present invention.

FIG. 4 is an explanatory view of another cancel coil that can be used in the laser heating apparatus according to the embodiment of the present invention, where (1) shows a form and (2) shows an arrangement example.

FIG. 5 is an explanatory diagram showing a laser heating device according to another embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a laser heating device according to another embodiment of the present invention.

[Explanation of symbols]

S laser heating device T heating target c coil c'cancel coil 1 heating means 2 stages 10 Magnetic field generating means 11 Source 12 Laser for magnetic field excitation 20 Squid magnetic field detection means 21 Squid part 22 Magnetic flux lock 30 Object Magnetic Field Change Extraction Means 31a Amplitude extraction unit 31b Phase change extraction unit 32a First multiplier 32b Second multiplier 33 shifter 34a First low-pass filter 34b Second low-pass filter 35a First squarer 35b Second squarer 36 adder 37 Square root device 38 Divider 39 Inverse tangent device 40 Output control means

Claims (7)

(57) [Claims] 1. A laser heating apparatus comprising a heating means for outputting a laser beam to heat an object to be heated, the stage supporting the object to be heated so that the laser beam can be irradiated, and the stage supported on the stage. A magnetic field generating means for generating a magnetic field with respect to the heating object, a SQUID magnetic field detecting means for detecting a heating magnetic field change occurring when the heating object is being heated by the heating means with a SQUID, and the SQUID magnetic field detecting means are An object magnetic field change extraction means for extracting an object magnetic field change caused by a structural change or a phase change of the object to be heated from a magnetic signal related to the detected heating magnetic field change, and the extracted object magnetic field change Based on the above laser light
And an output control means for controlling the output of the laser light of the heating means when irradiating the object to be heated , and the magnetic field generating means is configured to include a coil.
A magnetic field that cancels the magnetic field generated by the coil
And a cancel coil, wherein the output control means is based on the extracted object magnetic field change.
Then , a laser heating device having a function of controlling the annealing temperature to be optimum . 2. A heating object is heated by outputting a laser beam.
In a laser heating device having a heating means for performing the above , the above-mentioned object to be heated is supported so that it can be irradiated with the above-mentioned laser light.
Generates a magnetic field for the stage and the heating target supported on the stage
When the heating target is heated by the magnetic field generating means and the heating means,
Squid magnet for detecting changes in heating magnetic field caused by SQUID
Field detecting means and the heating magnetic field change detected by the SQUID magnetic field detecting means.
The magnetic signal from the
The magnetic field change of the object caused by phase change or phase change
Object magnetic field change extraction means for performing the laser light based on the extracted object magnetic field change
When irradiating the object to be heated,
With an output control means for controlling the output of the laser light
When the object to be heated is made of a semiconductor, the magnetic field generating means excites a magnetic field on the semiconductor surface.
A magnetic field excitation laser is provided, and the output control means is based on the extracted magnetic field change of the object.
Then , a laser heating device having a function of controlling the annealing temperature to be optimum . 3. The laser heating apparatus according to claim 1, wherein the object magnetic field change extraction means is configured to include an amplitude extraction section for extracting the amplitude of the magnetic signal. 4. The laser heating apparatus according to claim 1, wherein the object magnetic field change extraction means comprises a phase change extraction section for extracting a phase change of the magnetic signal. 5. The SQUID magnetic field detecting means comprises a differential SQUID .
The laser heating device according to 2, 3, or 4 . 6. The at least claim 1, 2, 3, 4, characterized in that a magnetic shield for shielding the above heating object and the SQUID magnetic field detection means from external magnetic fields or
Or the laser heating device according to item 5 . 7. A laser heating method for heating an object to be heated with laser light, according to any one of claims 1 to 6.
Using the laser heating device described above, the heating object is supported so that it can be irradiated with laser light, a magnetic field is applied to the heating object, and the laser light is irradiated to the heating object, and the heating object is heated. The change in the magnetic field that occurs when the SQUID is detected, and the laser light is heated
When irradiating an object, the magnetic field change detected by the SQUID
A laser heating method characterized in that the output of laser light is adjusted based on the conversion .