JP6935132B2 - Manufacturing method of electrostatic chuck plate - Google Patents

Description

The present invention relates to a method for manufacturing an electrostatic chuck plate used for holding a plate-shaped workpiece or the like.

When processing semiconductor wafers, optical device wafers, package substrates, etc. with cutting equipment, grinding equipment, laser processing equipment, etc., protective members such as adhesive tapes and hard substrates are applied to these plate-shaped workpieces. It is common to paste it. As a result, the workpiece can be protected from the impact applied during processing, transportation, and the like.

The above-mentioned protective member is usually attached to a work piece by an adhesive having a certain degree of adhesive strength. Therefore, for example, the protective member may not be easily peeled off from the work piece after processing. Further, when a disposable adhesive tape or the like that cannot be reused is used, the cost required for processing the workpiece tends to be high.

Therefore, in recent years, the development of an electrostatic chuck plate that attracts and holds a work piece by using static electricity has been promoted (see, for example, Patent Document 1). In this electrostatic chuck plate, for example, by forming an electrode for generating an attractive force due to static electricity in a comb-teeth shape, a strong attractive force is maintained even after the power supply to the electrode is stopped.

Japanese Unexamined Patent Publication No. 2016-51836

The electrodes of the electrostatic chuck plate represented by the above-mentioned comb-shaped electrodes are often formed by wet etching. However, this wet etching requires a mask that matches the pattern of the electrodes, so there is a problem that it is easy to increase the cost. Therefore, there has been a demand for a method for manufacturing an electrostatic chuck plate capable of forming an electrode at a lower cost.

The present invention has been made in view of such problems, and an object of the present invention is to provide a method for manufacturing an electrostatic chuck plate capable of forming an electrode at a lower cost than before.

According to one aspect of the present invention, it is a method of manufacturing an electrostatic chuck plate that attracts and holds an workpiece by an electrostatic force, and a conductor film containing a metal oxide is provided on the first surface side. After the resin sheet preparation step for preparing the resin sheet and the resin sheet preparation step, the conductor film is ablated with a laser beam having a wavelength that is transparent to the resin sheet, and the first surface of the resin sheet is processed. After the electrode forming step of forming positive and negative electrodes on the side and the electrode forming step, the electrode is attached to the insulating surface side made of an insulator of the base substrate, and the resin sheet is peeled off from the electrode. Provided is a method for manufacturing an electrostatic chuck plate comprising an electrode transfer step of transferring positive and negative electrodes to the insulating surface side of the base substrate.

In one aspect of the present invention described above, the resin sheet is a resin sheet that is transparent in the visible region, and the wavelength of the laser beam is preferably 1000 nm or more.

In the production how the electrostatic chuck plate according to one embodiment of the present invention, a conductive film with a laser beam ablation, because it forms a positive and negative electrode, when using a method such as easily wet etching costly In comparison, positive and negative electrodes can be formed at low cost.

FIG. 1A is a cross-sectional view schematically showing a state in which a conductor film is formed on a base substrate, and FIG. 1B is a cross-sectional view schematically showing a state in which the conductor film is ablated. FIG. 1 (C) is a cross-sectional view schematically showing the structure of the completed electrostatic chuck plate. It is a top view which shows typically the structure of the completed electrostatic chuck plate. It is a perspective view which shows typically the structure of the frame unit which used the electrostatic chuck plate. It is sectional drawing which shows typically the structure of the frame unit which used the electrostatic chuck plate. It is a perspective view which shows typically how the work piece is adsorbed on the frame unit. FIG. 6A is a cross-sectional view schematically showing how the conductor film is ablated by the method for manufacturing an electrostatic chuck plate according to a modified example, and FIG. 6B is a static electricity according to the modified example. FIG. 6C is a cross-sectional view schematically showing how the resin sheet is peeled off from the electrodes attached to the base substrate in the method for manufacturing an electric chuck plate, and FIG. 6C is a method for manufacturing an electrostatic chuck plate according to a modified example. It is sectional drawing which shows typically the structure of the electrostatic chuck plate manufactured in.

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. The method for manufacturing the electrostatic chuck plate according to the present embodiment includes a conductor film forming step (see FIG. 1 (A)) and an electrode forming step (see FIGS. 1 (B), 1 (C) and 2). include.

In the conductor film forming step, a conductor film containing a metal oxide is provided at least on the first surface side of the base substrate whose first surface is an insulator. In the electrode forming step, the conductor film is ablated with a laser beam having a wavelength that is transparent to the base substrate, and positive and negative electrodes are formed on the first surface side of the base substrate. Hereinafter, the wafer processing method according to the present embodiment will be described in detail.

In the method for manufacturing an electrostatic chuck plate according to the present embodiment, first, a conductor film forming step of providing a conductor film containing a metal oxide on a base substrate is performed. FIG. 1A is a cross-sectional view schematically showing a state in which the conductor film 3 is formed on the first surface (insulating surface) 1a side of the base substrate 1.

As shown in FIG. 1 (A), the base substrate 1 is made of a glass material such as soda glass, borosilicate glass, or quartz glass that is transparent to light in the visible region (wavelength: 360 nm to 830 nm). It is formed in a shape and has a generally flat first surface 1a and a second surface 1b. That is, the first surface 1a and the second surface 1b of the base substrate 1 are made of an insulator.

It is desirable that the diameter of the base substrate 1 is, for example, about the same as or larger than the diameter of the workpiece 11 (see FIG. 5 and the like) to be adsorbed. The thickness of the base substrate 1 is typically about 1 mm to 30 mm. However, there are no restrictions on the material, shape, structure, size, thickness, etc. of the base substrate 1.

For example, a base substrate 1 made of a material such as resin or ceramics can also be used. Further, the base substrate 1 may have at least the first surface 1a made of an insulator. Therefore, for example, a substrate made of a semiconductor, a conductor, or the like can be coated with an insulator and used as the base substrate 1.

In the conductor film forming step of the present embodiment, the conductor film 3 containing the metal oxide is formed on the entire first surface 1a side of the base substrate 1 by a method such as sputtering. As the metal oxide, it is desirable to use a material that is transparent to light in the visible region, such as indium tin oxide (ITO). As a result, the conductor film 3 becomes transparent in the visible region, so that the electrostatic chuck plate of the present embodiment can be used, for example, during laser processing using a laser beam in the visible region. The thickness of the conductor film 3 is typically about 1 μm to 100 μm.

However, there are no particular restrictions on the material, shape, size, thickness, forming method, etc. of the conductor film 3, and the conductor film 3 may be formed by, for example, CVD, vacuum deposition, coating, or the like. Further, the conductor film 3 can also be formed by a method of attaching the conductor film provided on the resin sheet to the first surface 1a side of the base substrate 1. In this case, for example, a transparent conductive film ELECRYSTA (registered trademark) manufactured by Nitto Denko KK may be used.

After the conductor film forming step, the conductor film 3 provided on the first surface 1a side of the base substrate 1 is ablated with a laser beam to perform an electrode forming step of forming positive and negative electrodes. FIG. 1B is a cross-sectional view schematically showing how the conductor film 3 is ablated. The electrode forming step is performed using, for example, a laser processing apparatus 2 as shown in FIG. 1 (B).

The laser processing apparatus 2 includes a chuck table 4 for sucking and holding the base substrate 1. The chuck table 4 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis substantially parallel to the vertical direction. Further, a moving mechanism (not shown) is provided below the chuck table 4, and the chuck table 4 is provided with a machining feed direction (first horizontal direction) and an indexing feed direction (second horizontal direction) by the moving mechanism. Move to.

A part of the upper surface of the chuck table 4 is a holding surface 4a for sucking and holding the base substrate 1. The holding surface 4a is connected to a suction source (not shown) via a suction path (not shown) formed inside the chuck table 4. By applying the negative pressure of the suction source to the holding surface 4a, the base substrate 1 is sucked and held by the chuck table 4.

A laser irradiation unit 6 is arranged above the chuck table 4. The laser irradiation unit 6 irradiates and condenses a laser beam 6a pulse-oscillated by a laser oscillator (not shown) at a predetermined position. The laser oscillator is configured to pulse-oscillate a laser beam 6a having a wavelength that is transparent to the base substrate 1 and can ablate the conductor film 3.

In the electrode forming step, first, an irradiation scheduled line (not shown) on which the laser beam 6a is irradiated is set on the conductor film 3. This irradiation schedule line needs to be set in a shape that separates the conductor film 3 into two or more. However, the timing of setting the scheduled irradiation line may be arbitrary. At least, the irradiation schedule line may be set before irradiating the conductor film 3 with the laser beam 6a.

Next, the second surface 1b side of the base substrate 1 is brought into contact with the holding surface 4a of the chuck table 4, and the negative pressure of the suction source is applied. As a result, the base substrate 1 is held by the chuck table 4 in a state where the conductor film 3 provided on the first surface 1a side is exposed upward. After that, the chuck table 4 is rotated and moved to adjust the positional relationship between the base substrate 1 and the laser irradiation unit 6.

Then, the chuck table 4 is moved while irradiating the laser beam 6a from the laser irradiation unit 6 toward the conductor film 3 so that the laser beam 6a is irradiated along the scheduled irradiation line (not shown). As a result, a part of the conductor film 3 can be removed by ablation processing, and an insulating region 3a along the scheduled irradiation line can be formed.

In the present embodiment, the conductor film 3 is irradiated with a laser beam 6a having a wavelength that is transparent to the base substrate 1. More specifically, for example, it is desirable to irradiate the conductor film 3 with a laser beam 6a having a wavelength of 500 nm or ^{more under the condition of 0.44 J / cm 2 or more.} Thereby, a part of the conductor film 3 can be removed to form the insulating region 3a while suppressing the deterioration of the base substrate 1.

When the insulating region 3a is formed in all of the scheduled irradiation lines, the conductor film 3 has a positive electrode pattern (positive electrode) 3b (see FIG. 1C, etc.) and a negative electrode pattern due to the insulating region 3a. It is separated into (negative electrode) 3c (see FIG. 1C and the like). That is, a positive electrode pattern 3b and a negative electrode pattern 3c are formed on the first surface 1a side of the base substrate 1. As a result, an electrostatic chuck plate 5 (see FIG. 1C and the like) having a positive electrode pattern 3b and a negative electrode pattern 3c on the first surface 1a side of the base substrate 1 is completed.

As described above, in the present embodiment, since it is only necessary to irradiate the laser beam 6a along the scheduled irradiation line of the conductor film 3, the time required for processing is shortened as compared with a method such as wet etching which requires a mask. Easy to do. Further, since it is not necessary to form a mask as in wet etching, the cost for forming the positive electrode pattern 3b and the negative electrode pattern 3c can be suppressed low.

FIG. 1C is a cross-sectional view schematically showing the structure of the electrostatic chuck plate 5, and FIG. 2 is a plan view schematically showing the structure of the electrostatic chuck plate 5. As shown in FIGS. 1C and 2, the shapes of the positive electrode pattern 3b and the negative electrode pattern 3c are, for example, a pair of comb teeth formed by alternately arranging the positive electrode and the negative electrode. It is good to set it to.

In such a comb-shaped electrode, since the positive electrode and the negative electrode are arranged at a high density, for example, a strong electrostatic force called a gradient force acting between the electrode and the workpiece 11 is also strong. Become. That is, the workpiece 11 can be attracted and held with a strong force. Further, even after the power supply to the positive electrode and the negative electrode is stopped, the strong adsorption force can be maintained.

However, there are no particular restrictions on the shape, size, etc. of the positive electrode pattern 3b and the negative electrode pattern 3c. For example, the positive electrode pattern 3b and the negative electrode pattern 3c can be formed of a curve, a circle, or the like. As shown in FIG. 2, by setting the irradiation schedule line on which the insulating region 3a is formed into a shape that allows one stroke, the time required for processing can be further shortened.

As described above, in the method for manufacturing the electrostatic chuck plate according to the present embodiment, the conductor film 3 is ablated with the laser beam 6a, and the positive electrode pattern (positive electrode) 3b and the negative electrode pattern (negative electrode) are processed. ) 3c is formed, so that the positive electrode pattern 3b and the negative electrode pattern 3c can be formed at a lower cost as compared with the case of using a method such as wet etching, which tends to cost more.

The electrostatic chuck plate 5 manufactured in this way is used by being incorporated into various devices for sucking and holding the workpiece 11. FIG. 3 is a perspective view schematically showing the structure of the frame unit 12 in which the electrostatic chuck plate 5 is used, and FIG. 4 is a schematic view of the structure of the frame unit 12 in which the electrostatic chuck plate 5 is used. It is sectional drawing which shows.

As shown in FIGS. 3 and 4, the frame unit 12 includes an annular frame 14 made of a material such as aluminum. An opening 14c is formed in the central portion of the frame 14 so as to penetrate the frame 14 from the first surface 14a to the second surface 14b. The shape of the opening 14c is, for example, substantially circular when viewed from the first surface 14a side (or the second surface 14b side). There are no particular restrictions on the material, shape, size, etc. of the frame 14.

A film-like base sheet 16 made of a material such as polyethylene (PE) or polyethylene terephthalate (PET) is fixed to the second surface 14b of the frame 14 so as to cover the opening 14c. Specifically, the outer peripheral portion of the circular base sheet 16 on the first surface 16a side is attached to the second surface 14b of the frame 14.

The base sheet 16 has, for example, flexibility enough to protect the workpiece 11 and insulating property not hindering the force of static electricity described later. However, there are no particular restrictions on the material, shape, thickness, size, etc. of the base sheet 16. The workpiece 11 is held on the first surface 16a side of the base sheet 16. On the other hand, the above-mentioned electrostatic chuck plate 5 is provided at the central portion of the base sheet 16 on the second surface 16b side.

In the electrostatic chuck plate 5, for example, the conductive film 3 (positive electrode pattern 3b and negative electrode pattern 3c) side is brought into close contact with the second surface 16b side of the base sheet 16 by the adhesive cover sheet 18. It is fixed. In this case, the electric field generated from the conductor film 3 is applied to the workpiece on the first surface 16a side as compared with the case where the second surface 1b side of the base substrate 1 is brought into close contact with the second surface 16b side of the base sheet 16. 11 can be made to act efficiently.

The cover sheet 18 includes, for example, a circular base sheet formed of the same material as the base sheet 16 and an adhesive layer (glue layer) provided on one surface of the base sheet. Here, the diameter of the cover sheet 18 (base material sheet) is larger than the diameter of the electrostatic chuck plate 5 (base substrate 1). However, there are no particular restrictions on the material, shape, thickness, size, structure, etc. of the cover sheet 18.

On the second surface 16b side of the base sheet 16, a first wiring 20a connected to the positive electrode pattern 3b and a second wiring 20b connected to the negative electrode pattern 3c are arranged. As shown in FIG. 3, a power feeding unit 22 is provided on the first surface 14a side of the frame 14, and the first wiring 20a and the second wiring 20b, for example, wrap around the frame 4 so that the power feeding unit 22 is provided. Connected to.

The power supply unit 22 includes a battery holder 22a for accommodating the battery 24 used for power supply to the positive electrode pattern 3b and the negative electrode pattern 3c described above. Further, a switch 22b for switching between feeding and non-feeding to the positive electrode pattern 3a and the negative electrode pattern 3b is provided at a position adjacent to the battery holder 22a.

For example, when the switch 22b is put into a conductive state (on state), the electric power of the battery 24 housed in the battery holder 22a is transferred to the positive electrode pattern 3b and the negative electrode pattern via the first wiring 20a and the second wiring 20b. It is supplied to 3c. On the other hand, when the switch 22b is set to the non-conducting state (off state), the power supply to the positive electrode pattern 3b and the negative electrode pattern 3c is stopped.

Although the power supply unit 22 is arranged on the first surface 14a side of the frame 14 in FIGS. 3 and 4, there is no particular limitation on the arrangement of the power supply unit 22 and the like. At least, the power feeding unit 22 may be arranged at a position that does not interfere with the use of the frame unit 12 (that is, sucking and holding the workpiece 11). For example, the power supply unit 22 can be arranged in the opening 14c of the frame 14. Further, the battery 24 may be a primary battery such as a button type battery (coin type battery) or a secondary battery that can be repeatedly used by charging.

FIG. 5 is a perspective view schematically showing how the workpiece 11 is adsorbed on the frame unit 12. The workpiece 11 is, for example, a disk-shaped wafer made of a material such as silicon (Si). The surface 11a side of the workpiece 11 is divided into a plurality of regions by scheduled division lines (streets) 13 set in a grid pattern, and each region includes an IC (Integrated Circuit) and a MEMS (Micro Electro Mechanical). A device 15 such as Systems) is formed.

However, there are no restrictions on the material, shape, structure, size, etc. of the workpiece 11. The work piece 11 made of other materials such as semiconductors, ceramics, resins, and metals can be adsorbed and held by the frame unit 12. Similarly, there are no restrictions on the type, quantity, shape, structure, size, arrangement, etc. of the device 15.

When adsorbing the work piece 11 to the frame unit 12, first, the work piece 11 is brought into contact with the base sheet 16 so that the back surface 11b side of the work piece 11 and the first surface 16a side of the base sheet 16 come into contact with each other. Put on. More specifically, the workpiece 11 is placed on the region (central portion) of the base sheet 16 corresponding to the electrostatic chuck plate 5. Next, the switch 22b of the power feeding unit 22 is brought into a conductive state, and the electric power of the battery 24 is supplied to the positive electrode pattern 3b and the negative electrode pattern 3c.

As a result, an electric field is generated around the positive electrode pattern 3b and the negative electrode pattern 3c, and as an effect, an electrostatic force acts between the workpiece 11 and the conductor film 3. The workpiece 11 is attracted to and held by the frame unit 12 by the force of static electricity. The electrostatic force acting between the workpiece 11 and the conductor film 3 includes a Coulomb force, a Johnson-Labeck force, a gradient force, and the like.

The present invention is not limited to the description of the above embodiment and can be implemented with various modifications. For example, in the above embodiment, after the conductor film 3 containing the metal oxide is provided on the base substrate 1, the conductor film 3 is ablated with the laser beam 6a, but the electrostatic chuck plate is subjected to another procedure. 5 can also be manufactured.

FIG. 6A is a cross-sectional view schematically showing how the conductor film 3 is ablated by the method for manufacturing an electrostatic chuck plate according to a modified example. In the method for manufacturing an electrostatic chuck plate according to a modified example, first, a resin sheet preparation step of preparing a resin sheet 7 provided with a conductor film 3 containing a metal oxide is performed.

The resin sheet 7 is formed of, for example, a resin material such as polyethylene terephthalate (PET) that is transparent to light in the visible region, and a conductor film 3 containing a metal oxide is formed on the first surface 7a side thereof. Is provided. As the resin sheet 7 with such a conductor film 3, for example, a transparent conductive film ELECRYSTA (registered trademark) manufactured by Nitto Denko KK can be used.

After the resin sheet preparation step, the conductor film 3 provided on the first surface 7a side of the resin sheet 7 is ablated with a laser beam 6a to perform an electrode forming step of forming positive and negative electrodes. The electrode forming step is performed using, for example, the laser processing apparatus 2. Most of the configurations of the laser processing device 2 used in this modification are the same as those of the laser processing device 2 used in the above embodiment, but the laser oscillator has transparency to the resin sheet 7. It is configured to pulse-oscillate a laser beam 6a having a wavelength capable of ablating the conductor film 3.

In the electrode forming step according to the modified example, first, an irradiation scheduled line (not shown) on which the laser beam 6a is irradiated is set on the conductor film 3. This irradiation schedule line needs to be set in a shape that separates the conductor film 3 into two or more. However, the timing of setting the scheduled irradiation line may be arbitrary. At least, the irradiation schedule line may be set before irradiating the conductor film 3 with the laser beam 6a.

Next, the second surface 7b side of the resin sheet 7 is brought into contact with the holding surface 4a of the chuck table 4, and the negative pressure of the suction source is applied. As a result, the resin sheet 7 is held on the chuck table 4 in a state where the conductor film 3 provided on the first surface 7a side is exposed upward. Next, the chuck table 4 is rotated and moved to adjust the positional relationship between the resin sheet 7 and the laser irradiation unit 6.

Then, the chuck is while irradiating the laser beam 6a from the laser irradiation unit 6 toward the conductor film 3 so that the laser beam 6a is irradiated along the scheduled irradiation line (not shown) set on the conductor film 3. Move the table 4. As a result, a part of the conductor film 3 can be removed by ablation processing, and an insulating region 3a along the scheduled irradiation line can be formed.

In this modification, the conductor film 3 is irradiated with a laser beam 6a having a wavelength that is transparent to the resin sheet 7. More specifically, for example, it is desirable to irradiate the conductor film 3 with a laser beam 6a having a wavelength of 1000 nm or more ^{under the condition of 0.44 J / cm 2} or more and less than 8.84 J / cm ^2. As a result, a part of the conductor film 3 can be removed to form the insulating region 3a without deteriorating or damaging the resin sheet 7 as in the case of using a laser beam in the ultraviolet region (wavelength: less than 360 nm).

When the insulating region 3a is formed on the entire irradiation schedule line, the conductor film 3 is separated into a positive electrode pattern (positive electrode) 3b and a negative electrode pattern (negative electrode) 3c by the insulating region 3a. Will be done. That is, a positive electrode pattern 3b and a negative electrode pattern 3c are formed on the first surface 7a side of the resin sheet 7.

After the electrode forming step, an electrode relocation step of relocating the positive electrode pattern 3b and the negative electrode pattern 3c to the first surface (insulating surface) 1a side of the base substrate 1 is performed. In this electrode transfer step, for example, the positive electrode pattern 3b and the negative electrode pattern 3c on the resin sheet 7 are attached to the first surface 1a side of the base substrate 1, and then the resin sheet 7 is peeled off.

FIG. 6B schematically shows how the resin sheet 7 is peeled off from the positive electrode pattern 3b and the negative electrode pattern 3c attached to the base substrate 1 in the method of manufacturing the electrostatic chuck plate according to the modified example. It is sectional drawing which shows. As shown in FIG. 6B, the positive electrode pattern 3b and the negative electrode pattern 3c are attached to the first surface 1a side of the base substrate 1 by using the adhesive 9. The base substrate 1 may be the same as the base substrate 1 used in the above embodiment.

After the positive electrode pattern 3b and the negative electrode pattern 3c are attached to the first surface 1a side of the base substrate 1 using the adhesive 9, the resin sheet 7 is applied from the positive electrode pattern 3b and the negative electrode pattern 3c. Peel off. As a result, the positive electrode pattern 3b and the negative electrode pattern 3c are transferred to the first surface 1a side of the base substrate 1, and the electrostatic chuck plate 5a is completed. FIG. 6C is a cross-sectional view schematically showing the structure of the electrostatic chuck plate manufactured by the method for manufacturing the electrostatic chuck plate according to the modified example.

As described above, also in the method of manufacturing the electrostatic chuck plate according to the modified example, the conductor film 3 is ablated with the laser beam 6a to form a positive electrode pattern (positive electrode) 3b and a negative electrode pattern (negative electrode). Since 3c is formed, the positive electrode pattern 3b and the negative electrode pattern 3c can be formed at a lower cost than when a method such as wet etching, which tends to be costly, is used.

In addition, the structures, methods, and the like according to the above-described embodiments and modifications can be appropriately modified and implemented as long as they do not deviate from the scope of the object of the present invention.

1 Base substrate 1a 1st surface (insulation surface)
1b 2nd surface 3 Conductor film 3a Insulation area 3b Positive electrode pattern (positive electrode)
3c Negative electrode pattern (negative electrode)
5,5a Electrostatic chuck plate 7 Resin sheet 7a 1st surface 7b 2nd surface 9 Adhesive 2 Laser processing device 4 Chuck table 4a Holding surface 6 Laser irradiation unit 6a Laser beam 12 frame unit 14 frame 14a 1st surface 14b 2nd Surface 14c Opening 16 Base sheet 16a First surface 16b Second surface 18 Cover sheet 20a First wiring 20b Second wiring 22 Power supply unit 22a Battery holder 22b Switch 24 Battery

Claims (2)

A method for manufacturing an electrostatic chuck plate that attracts and holds an workpiece by the force of static electricity.
A resin sheet preparation step for preparing a resin sheet provided with a conductor film containing a metal oxide on the first surface side, and
After the resin sheet preparation step, an electrode forming step in which the conductor film is ablated with a laser beam having a wavelength transparent to the resin sheet to form positive and negative electrodes on the first surface side of the resin sheet. When,
After the electrode forming step, the electrodes are attached to the insulating surface side of the base substrate made of an insulator, and the resin sheet is peeled off from the electrodes to transfer the positive and negative electrodes to the insulating surface side of the base substrate. A method of manufacturing an electrostatic chuck plate, comprising: The resin sheet is a resin sheet that is transparent in the visible region.
The method for manufacturing an electrostatic chuck plate according to claim 1 , wherein the wavelength of the laser beam is 1000 nm or more.

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