JP5293211B2 - Electrostatic chuck and method of manufacturing electrostatic chuck - Google Patents

Abstract

An electrostatic chuck is provided with: a ferroelectric substrate having a protruding section formed on the main surface on the side where a subject to be processed is to be placed and a flat section formed at the periphery of the protruding section; and a covering section formed to cover the protruding section and the flat section.  At least on a part of the flat section, a region where the covering section is not formed is provided. In a method for manufacturing an electrostatic chuck, the dielectric substrate main surface opposite to the main surface where an electrode is provided is polished, a mask having a desired shape is arranged on the polished main surface, and the portion not covered with the mask is removed using a sandblast method so as to form a flat section and a protruding section.  Then, a resin is applied to cover the protruding section and the flat section, and the surface of the resin applied on the top surface of the protruding section is polished so as to make the arithmetic average height of the surface of the resin applied on the top surface of the protruding section less than that of the surface of the resin applied on the upper surface of the flat section, and the covering section is formed by cutting a part of the resin applied on the upper surface of the flat section and removing the cut resin. Generation of particle contamination is suppressed, the subject to be processed can be excellently removed, and the covering section formed on a part of the placing surface of the electrostatic chuck has improved durability to peeling.

Description

  Aspects of the invention generally relate to electrostatic chucks.

Electrostatic chucks are used as a means to attract and hold semiconductor wafers and glass substrates, etc., to be processed in substrate processing equipment that performs etching, CVD (Chemical Vapor Deposition), sputtering, ion implantation, ashing, exposure, inspection, etc. ing. Examples of the electrostatic chuck include a Coulomb electrostatic chuck that generates a Coulomb force to attract a workpiece, and a Johnsen-Rabeck electrostatic chuck that generates a strong adsorption force by generating a Johnsen-Rabeck force. Are known.
Here, if the mounting surface of the electrostatic chuck and the object to be processed are rubbed, there is a risk of particle contamination. In this case, there is a higher possibility that particle contamination will occur in an electrostatic chuck that can exhibit a strong attracting force, such as a Johnsen-Rahbek type electrostatic chuck. In addition, the detachment response of the object to be processed may be deteriorated.

  For this reason, there has been proposed an electrostatic chuck that reduces the contact area by providing a protrusion on the mounting surface portion of the electrostatic chuck, thereby suppressing particle contamination and improving the detachment response of the workpiece. In addition, a technique for further suppressing particle contamination and generation of scratches by covering the mounting surface of the electrostatic chuck with a resin has been proposed (see FIG. 1A of Patent Document 1). However, according to the study by the present inventors, if the entire mounting surface of the electrostatic chuck is covered with resin as disclosed in Patent Document 1, charges remain in the resin layer and the object to be processed It became clear that the withdrawal responsiveness of was worsened.

In addition, a technique for forming a protrusion made of a resin that holds an object to be processed on a flat ceramic layer has also been proposed (see FIG. 2B of Patent Document 1).
However, according to the study by the present inventors, when a protrusion made of resin is formed on a flat ceramic layer, peeling may occur at the interface between the ceramic layer and the protrusion. It has become clear that it is easy to progress by external force. For example, when forming a protrusion made of resin, the upper surface of a flat ceramic layer is covered with resin, and the peripheral resin is peeled away leaving the protrusion. According to such a manufacturing method, when the resin around the protrusion is peeled off, a force may also act on the protrusion in the peeling direction. When a force in the peeling direction is applied to the protrusions, minute peeling may occur at the interface between the ceramic layer and the protrusions. Once the minute peeling occurs, the generated peeling easily develops due to external force. It became clear that. In particular, it has been found that when the object to be processed is adsorbed on the protrusions made of resin and then the object to be processed is released, if the protrusions are pulled on the object to be processed, the peeling easily proceeds. This is presumably because the tensile strength of the resin itself forming the protrusions is greater than the adhesion strength at the interface.

In addition, a technique has been proposed in which a protrusion is formed on the ceramic layer itself and a resin layer is formed so as to cover only the top surface of the protrusion (see FIG. 2A of Patent Document 1).
However, even in such a case, the peeling is likely to progress for the same reason as described above.

  In the technique disclosed in Patent Document 1, consideration is not given to the base of the resin to be coated, and the arithmetic average height at the contact portion with the object to be processed (the surface of the resin on the top surface of the protrusion). There is a possibility that a chip pocket is formed in this portion. For this reason, fine particles may enter the chip pocket, and the particles may be released later to cause particle contamination. In addition, there is a possibility that the adhesive force of the resin may be reduced around the protrusion.

Also, a method for manufacturing an electrostatic chuck component has been proposed in which two or more kinds of raw material monomers are evaporated and a raw material monomer is vapor-deposited on a substrate to form a coating film of an insulating material (see Patent Document 2).
However, even in the technique disclosed in Patent Document 2, no consideration is given to the base of the resin to be coated, and as in the technique disclosed in Patent Document 1, the occurrence of particle contamination and the resin around the protrusions There was a possibility that the adhesion strength of the steel would be reduced.

JP 2006-287210 A JP-A-63-181345

  The aspect of the present invention has been made based on recognition of such a problem, can suppress the occurrence of particle contamination, has a good detachment response of an object to be processed, and is placed on the mounting surface portion of the electrostatic chuck. Provided are an electrostatic chuck and a manufacturing method of the electrostatic chuck having high peeling durability of a formed covering portion.

According to one aspect of the present invention, a dielectric substrate having a plurality of protrusions formed on a main surface on a side on which an object to be processed is placed, and a flat surface formed around the plurality of protrusions. And a covering portion formed so as to cover the plurality of protrusions and the flat portion, and the volume resistivity of the covering portion at 25 ° C. is 10 ¹⁴ Ωcm. Above, 10 ¹⁸ Ωcm or less, and in a part of the region on the planar portion between the plurality of protrusions, a region where the covering portion is not formed on the planar portion is provided, There is provided an electrostatic chuck characterized in that the amount of electric charge remaining in the part is suppressed.

According to another aspect of the present invention, the main surface of the dielectric substrate opposite to the main surface provided with the electrodes is polished, a mask having a desired shape is provided on the main surface, and the sandblast method is performed. And removing a portion that is not covered by the mask to form a plane portion and a projection portion, and covering the projection portion and the plane portion with resin so as to cover the projection portion. The top surface of the protrusion was coated such that the arithmetic average height of the surface of the resin coated on the top surface was smaller than the arithmetic average height of the surface of the resin coated on the top surface of the flat portion. Polishing the surface of the resin, cutting a part of the resin coated on the upper surface of the flat portion, and removing the cut resin provided a region where the resin is not formed the coated portion formed by charge remaining on the resin Suppressing the amount, method of manufacturing an electrostatic chuck according to claim is provided.

  According to the aspect of the present invention, the occurrence of particle contamination can be suppressed, the detachment response of the object to be processed is good, and the peeling durability of the covering portion formed on the mounting surface portion of the electrostatic chuck is high. An electrostatic chuck and a method for manufacturing the electrostatic chuck are provided.

1 is a schematic cross-sectional view for illustrating an electrostatic chuck according to an embodiment of the present invention. It is a schematic cross section for illustrating the range where a plane part is covered with a covering part. It is a flowchart for illustrating the manufacturing method of an electrostatic chuck. It is a schematic cross section for illustrating the electrostatic chuck which concerns on other embodiment of this invention. 5 is a flowchart for illustrating a specific example of a method for manufacturing the electrostatic chuck shown in FIG. 4.

An embodiment of the first invention is a dielectric substrate having a plurality of protrusions formed on a main surface on a side on which an object to be processed is placed, and a flat surface formed around the plurality of protrusions. And a covering portion formed so as to cover the plurality of protrusions and the flat portion, and the volume resistivity of the covering portion at 25 ° C. is 10 ¹⁴ Ωcm. Above, 10 ¹⁸ Ωcm or less, and in a part of the region on the planar portion between the plurality of protrusions, a region where the covering portion is not formed on the planar portion is provided, An electrostatic chuck characterized in that the amount of electric charge remaining in the part is suppressed.
According to this electrostatic chuck, the occurrence of particle contamination can be suppressed. Further, it is possible to improve the detachment response of the object to be processed and the peeling durability of the covering portion formed on the mounting surface portion of the electrostatic chuck.

According to a second aspect of the present invention, in the first aspect of the present invention, the covering portion is separated from the protrusion from a position where the side surface of the protrusion intersects the flat surface on the flat surface. The electrostatic chuck is characterized in that it is formed in a range of not less than the thickness dimension of the covering portion and not more than 3 mm in a direction to be applied.
According to this electrostatic chuck, it is possible to further suppress particle contamination, improve the detachment response of the object to be processed, and improve the peeling durability of the covering portion.

In addition, according to an embodiment of the third invention, in the embodiment of the first or second invention, the volume resistivity of the dielectric substrate in the use temperature region of the electrostatic chuck is 10 ⁹ Ωcm or more and 10 ¹¹ Ωcm or less. It is an electrostatic chuck characterized by being.
According to this electrostatic chuck, it is possible to improve the adsorption / desorption response of the workpiece without increasing the current value of the adsorption voltage.

An embodiment of the fourth invention is an electrostatic chuck according to any one of the first to third inventions, wherein the covering portion includes a polyimide resin.
According to this electrostatic chuck, it is possible to have a coating portion that has excellent corrosion resistance and excellent coating characteristics.

An embodiment of a fifth invention is the electrostatic chuck according to any one of the first to fourth inventions, wherein the covering portion is formed using a vapor deposition polymerization method. It is. According to this electrostatic chuck, it is possible to have a coating portion with excellent coating characteristics.

Further, according to an embodiment of the sixth invention, in the embodiment of any one of the first to fifth inventions, the contact area ratio between the surface of the covering portion and the object to be processed on the top surface of the protrusion is 0. The electrostatic chuck is characterized by being 0.005% or more and 1.5% or less.
According to this electrostatic chuck, it is possible to suppress particle contamination and improve the detachment response of the object to be processed. In addition, the formation of the protrusion can be facilitated.

In an embodiment of the seventh aspect of the invention, a main surface opposite to a main surface on which an electrode of a dielectric substrate is provided is polished, a mask having a desired shape is provided on the main surface, and the mask is formed using a sandblast method. A flat portion is formed by removing a portion that is not covered by the projection, and a projection is formed. The resin is covered so as to cover the projection and the plane, and the top surface of the projection is covered. The surface of the resin coated on the top surface of the protrusion so that the arithmetic average height of the surface of the resin is smaller than the arithmetic average height of the surface of the resin coated on the upper surface of the flat portion Polishing is performed, a part of the resin coated on the upper surface of the flat part is cut, and the cut resin is removed to form a covering part provided with a region where the resin is not formed suppressing the amount of charge remaining in the resin and Rukoto a manufacturing method of an electrostatic chuck according to claim.
According to this method for manufacturing an electrostatic chuck, it is possible to manufacture an electrostatic chuck capable of suppressing particle contamination, improving the detachment response of the object to be processed, and improving the peeling durability of the covering portion.

An eighth embodiment of the present invention is the method for manufacturing an electrostatic chuck according to the seventh embodiment, wherein the resin is coated using a vapor deposition polymerization method.
According to this method for manufacturing an electrostatic chuck, it is possible to coat a resin with excellent coating characteristics.

An ninth embodiment of the present invention is the electrostatic chuck according to the seventh or eighth embodiment, wherein the resin is cut using a laser processing method or a water jet processing method. It is a manufacturing method.
According to this method for manufacturing an electrostatic chuck, the occurrence of burrs and burrs can be suppressed when the resin is cut.

Hereinafter, embodiments of the present invention will be illustrated with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.
FIG. 1 is a schematic cross-sectional view for illustrating an electrostatic chuck according to an embodiment of the present invention. 1A is a schematic cross-sectional view for illustrating an electrostatic chuck, and FIG. 1B is a schematic enlarged view of a portion B in FIG. 1A.
As shown in FIGS. 1A and 1B, the electrostatic chuck 1 is provided with a base 2, a dielectric substrate 3, and an electrode 4.
An insulator layer 5 made of an inorganic material is formed on one main surface (surface on the electrode 4 side) of the base 2. In addition, the dielectric substrate 3 has a protrusion 3a formed on the main surface on the side where the object to be processed is placed, and a flat surface 3b formed around the protrusion 3a.

The covering portion 7 is formed so as to cover the protruding portion 3a and the flat portion 3b formed in the periphery thereof. Moreover, the coating | coated part 7 is formed in the predetermined range, and the part in which the coating | coated part 7 is not formed is provided between adjacent projection parts 3b. That is, the covering portions 7 that are separated from each other are formed, and at least a part of the flat surface portion 3b is provided with a region where the covering portion 7 is not formed. Further, the planar portion 3b of the dielectric substrate 3 is exposed in a region where the covering portion 7 is not formed.
Moreover, the surface of the coating | coated part 7 in the top surface of the projection part 3a is a mounting surface of to-be-processed objects, such as a semiconductor wafer.

Here, as in the technique disclosed in FIG. 2B of Patent Document 1 (Japanese Patent Laid-Open No. 2006-287210), the entire planar portion 3b on the side on which the object to be processed of the dielectric substrate 3 is placed. If the coating part 7 is covered, the amount of electric charge remaining in the coating part 7 increases, so that the detachment response of the workpiece is deteriorated.
In addition, if the polarity of the residual charge and the polarity of the applied voltage are the same polarity, the attractive force will be strong, and if it is different, the attractive force will be weak, which will cause the attractive force to become unstable. It also becomes.

  According to the present embodiment, since the portion covered with the covering portion 7 is limited to a necessary range, the amount of remaining charge can be suppressed. That is, the cover 3 is formed so as to cover a predetermined range of the flat surface portion 3b around the protrusion 3a that is a portion that rubs against the object to be processed and the protrusion 3a. Therefore, a portion where the covering portion 7 is not formed is provided between the adjacent protrusions 3b, and the amount of remaining charge can be reduced by the portion where the covering portion 7 is not formed. As a result, it is possible to improve the detachment response of the object to be processed and to obtain a stable adsorption force.

  In this case, as in the technique disclosed in FIG. 2A of Patent Document 1 (Japanese Patent Laid-Open No. 2006-287210), the covering portion 7 is formed so as to cover only the top surface of the protruding portion 3a. However, peeling of the covering portion 7 tends to progress, and a new problem arises that burrs and burrs are generated on the mounting surface.

  That is, when the covering portion 7 is partially formed, the planar portion 3b is covered with the resin together with the protruding portion 3a, and unnecessary portions are peeled off while leaving necessary portions. In this case, when the unnecessary portion is peeled off, the end portion of the covering portion 7 may be pulled in the peeling direction to cause minute peeling. Then, when an external force is applied in the peeling direction to the part where such peeling occurs, the peeling easily progresses.

According to the present embodiment, the portion to which an external force is applied can be separated from the end portion of the covering portion 7 that is likely to be peeled due to manufacturing, and thus the force applied in the peeling direction at the end portion of the covering portion 7 is suppressed. Can do. Therefore, progress of peeling can be suppressed.
That is, since the covering portion 7 is formed so as to cover the protruding portion 3a and the surrounding flat portion 3b, the top surface of the protruding portion 3a to which an external force is applied to the end portion of the covering portion 7 that is likely to be peeled due to manufacturing. Can be separated from the vicinity. Therefore, even when an external force (external force acting in the peeling direction) that pulls the covering portion 7 in the vicinity of the top surface of the protruding portion 3a is generated when the workpiece is adsorbed and separated, the end portion of the covering portion 7 Can reduce the external force (external force acting in the peeling direction) that pulls the end of the covering portion 7 upward. As a result, it can be set as the structure where generation | occurrence | production and progress of peeling do not arise easily.

  In addition, there is a possibility that burrs and burrs facing in the peeling direction may occur at the boundary with the part to be peeled off when peeling the unnecessary part of the resin, that is, at the end of the covering part 7. When such burrs and burrs are generated on the surface on which the object to be processed is placed, there is a risk that the surface on the object to be processed will be damaged and the number of particles will increase.

  According to the present embodiment, it is possible to provide the end portion of the covering portion 7 that is likely to generate burrs and burrs in the manufacturing process at a position separated from the surface on which the workpiece is placed. For this reason, even if burrs or burrs are generated at the end of the covering portion 7, it is possible to prevent the burrs or burrs from touching the surface on which the workpiece is placed. As a result, it is possible to suppress damage to the surface on the placement side of the object to be processed and increase in the number of particles.

Here, the range in which the flat surface portion 3b is covered with the covering portion 7 around the protrusion portion 3a will be further described.
FIG. 2 is a schematic cross-sectional view for illustrating a range in which the flat portion is covered by the covering portion. FIG. 2 shows a case where the shape of the protrusion 3a is substantially a truncated cone.
Table 1 is a table for illustrating the evaluation results for the release response after long-time adsorption. The evaluation of the release responsiveness of the object to be processed after long-time adsorption is performed by continuously preloading the object to be processed with a force of 100 gf after the continuous adsorption for 3 hours, turning off the applied voltage, Judgment is made based on whether or not it can be withdrawn within 3 seconds. In this case, it is indicated as “◯” when it is detached and “X” when it is not.

図２、表１に示すように、平面部３ｂが被覆部７により覆われる範囲（被覆部幅Ｌ）は、突起部３ａの側面と平面部３ｂとが交わる位置３ｄを基準とした場合、被覆部７の厚み寸法以上、３ｍｍ以下とすることが好ましい。すなわち、被覆部７は、平面部３ｂ上において、突起部３ａの側面と平面部３ｂとが交わる位置から突起部３ａから離隔する方向に被覆部７の厚み寸法以上、３ｍｍ以下の範囲に形成されるようにすることが好ましい。
被覆部幅Ｌを被覆部７の厚み寸法未満とすれば、平面部３ｂ上を覆う部分の形成が困難となり、また、突起部３ａ部分に形成される被覆部７の剥離耐久性が低くなるおそれがあるからである。また、３ｍｍを超えるものとすれば、残留電荷による吸着力が大きくなりすぎるので、表１に示すように被処理物の離脱応答性が悪化するおそれがあるからである。

As shown in FIG. 2 and Table 1, the range in which the flat surface portion 3b is covered with the covering portion 7 (covering portion width L) is covered when the position 3d where the side surface of the protruding portion 3a and the flat surface portion 3b intersect is a reference. It is preferable to set the thickness of the portion 7 to 3 mm or less. That is, the covering portion 7 is formed on the flat surface portion 3b in a range from the thickness dimension of the covering portion 7 to 3 mm or less in a direction away from the protruding portion 3a from the position where the side surface of the protruding portion 3a intersects the flat surface portion 3b. It is preferable to do so.
If the covering portion width L is less than the thickness dimension of the covering portion 7, it is difficult to form a portion covering the flat portion 3b, and the peeling durability of the covering portion 7 formed on the protruding portion 3a may be reduced. Because there is. Further, if the thickness exceeds 3 mm, the adsorption force due to the residual charge becomes too large, so that the detachment response of the object to be processed may be deteriorated as shown in Table 1.

  Moreover, as shown in Table 1, it is preferable that the covering portion covering ratio obtained by dividing the area of the covering portion 7 by the area of the object to be processed exceeds 0% and not more than 40%. In this case, it is more preferable to exceed 0% and not more than 30%. Moreover, it is more preferable to exceed 0% and not more than 25%. When 0%, that is, when the covering portion 7 is not formed, charges are accumulated in the object to be processed, and the detachment response may be deteriorated. Further, if it exceeds 40%, the amount of electric charge remaining in the covering portion 7 becomes too large, so that the detachment response of the object to be processed may be deteriorated. Here, since reducing the amount of charge remaining in the covering portion 7 leads to improvement in the release response, it is more preferable that the covering portion covering ratio is low. Therefore, it is preferably 30% or less, and more preferably 25% or less.

Next, returning to FIG. 1, other components of the electrostatic chuck 1 will be described.
The main surface of the dielectric substrate 3 provided with the electrode 4 and the main surface of the base 2 provided with the insulator layer 5 are bonded with an insulating adhesive. The bonding layer 6 is obtained by curing the insulating adhesive.
The electrode 4 and the power source 10a and the power source 10b are connected by an electric wire 9. In addition, although the electric wire 9 is provided so that the base 2 may be penetrated, the electric wire 9 and the base 2 are insulated. An example illustrated in FIG. 1 is a so-called bipolar electrostatic chuck in which a positive electrode and a negative electrode are formed on a dielectric substrate 3 so as to be adjacent to each other. However, the present invention is not limited to this, and may be a so-called monopolar electrostatic chuck in which one electrode is formed on the dielectric substrate 3, or a tripolar type or other multipolar type. . In addition, the number and arrangement of the electrodes can be changed as appropriate.

  A through hole 11 is provided so as to penetrate the electrostatic chuck 1. One end of the through hole 11 is open to the flat portion 3b, and the other end is connected to a gas supply means (not shown) via a pressure control means and a flow rate control means (not shown). In addition, when the coating | coated part 7 is formed in the area | region where the through-hole 11 opens, the through-hole 11 is opened on the upper surface of the coating | coated part 7 so that the coating | coated part 7 may be penetrated.

  A gas supply means (not shown) supplies helium gas or argon gas. And the space 3c provided by forming the protrusion part 3a becomes a passage of the supplied gas. Further, the spaces 3c communicate with each other, and the supplied gas spreads throughout.

  In addition, a ring-shaped protrusion (not shown) is disposed around the outer peripheral portion of the surface on which the object to be processed such as a semiconductor wafer is placed and the through holes other than the through holes 11 for supplying the gas. Can also be prevented from leaking. Also in this ring-shaped protrusion, the covering portion 7 can be formed in the same manner as the protrusion 3a. That is, it is possible to cover the predetermined range of the side surface, the top surface, and the flat surface portion 3b around the ring-shaped projection portion (not shown) with the covering portion 7.

  Furthermore, by providing a gas distribution groove (concave groove) (not shown) that is provided radially and concentrically on the flat portion 3b and communicates with the through hole 11, the gas distribution speed can be increased. Then, a predetermined range of the side surface and bottom surface of the gas distribution groove and the flat surface portion 3b around the gas distribution groove can be covered with the covering portion 7.

  The base 2 can be formed of, for example, a metal having a high thermal conductivity such as an aluminum alloy or copper. And the flow path 8 through which a cooling liquid or a heating liquid flows can be provided in the inside. In addition, although the flow path 8 is not necessarily required, it is preferable that it is provided from the viewpoint of temperature control of the object to be processed.

The insulator layer 5 provided on one main surface of the base 2 can be formed of a polycrystalline material such as alumina (Al ₂ O ₃ ) or yttria (Y ₂ O ₃ ). The insulator layer 5 preferably has a higher thermal conductivity than the bonding layer 6, and more preferably has a thermal conductivity of 2 W / mK or more. By doing so, the heat transfer property becomes better than the case of the bonding layer alone, and the temperature controllability of the object to be processed and the uniformity of the in-plane temperature can be further improved.

  In the bonding layer 6, it is preferable to increase its thermal conductivity. For example, the thermal conductivity is preferably 1 W / mK or more, and more preferably 1.6 W / mK or more. Such thermal conductivity can be obtained, for example, by adding alumina or aluminum nitride as a filler to a silicone resin or the like. Moreover, thermal conductivity can also be adjusted with the ratio of addition.

  The thickness of the bonding layer 6 is preferably as thin as possible in consideration of heat transferability. On the other hand, considering that the bonding layer 6 is peeled off due to thermal shear stress caused by the difference in thermal expansion coefficient between the base 2 and the dielectric substrate 3, the thickness of the bonding layer 6 should be as thick as possible. preferable. Therefore, the thickness of the bonding layer 6 is preferably set to 0.1 mm or more and 0.3 mm or less in consideration of these.

  As the dielectric substrate 3, various materials can be used according to various requirements required for the electrostatic chuck. In this case, considering the thermal conductivity and the reliability of electrical insulation, it is preferable to use a ceramic sintered body. Specific examples of the ceramic sintered body include alumina, yttria, aluminum nitride, silicon carbide and the like.

The volume resistivity of the material of the dielectric substrate 3 is preferably 10 ⁸ Ωcm or more in the operating temperature range. In this case, it is more preferable that the volume resistivity is 10 ⁹ Ωcm or more and 10 ¹¹ Ωcm or less in the operating temperature range. This is because if it is less than 10 ⁹ Ωcm, the current value of the applied voltage becomes too large. Further, if it exceeds 10 ¹¹ Ωcm, the release response may be deteriorated.

  The dielectric substrate 3 is preferably a ceramic sintered body having an average particle diameter of 2 μm or less. If a ceramic sintered body having an average particle diameter of 2 μm or less is used, even if a part of the covering portion 7 is eroded or peeled off, it is possible to suppress the occurrence of large-sized degranulation. Because it can.

In the case of an electrostatic chuck having a volume resistivity of 10 ⁹ Ωcm or more and 10 ¹¹ Ωcm or less in the operating temperature range, the thickness of the dielectric substrate 3 is required for use in a practical voltage range (± 500 V to ± 2000 V). Is preferably 1.5 mm or less. In consideration of ease of manufacture, the thickness of the dielectric substrate 3 is preferably 0.2 mm or more (more preferably 0.3 mm or more).

  In addition, it is preferable that the total thickness of the dielectric substrate 3 and the coating | coated part 7 is 0.5 mm or more and 2.0 mm or less. By setting it as such thickness, the electrical insulation between a to-be-processed object and an electrode is securable. In addition, an electrostatic chuck having good heat transfer from the workpiece to the base can be obtained.

  Examples of the material of the electrode 4 include titanium oxide, titanium alone or a mixture of titanium and titanium oxide, titanium nitride, titanium carbide, tungsten, gold, silver, copper, aluminum, chromium, nickel, and gold-platinum. Can do.

  Here, the material, volume resistivity, thickness dimension and variation thereof, arithmetic average height, and the like of the covering portion 7 have a great influence on corrosion resistance, generation of particle contamination, detachment response, and the like. Therefore, it is important to keep the volume resistivity, thickness dimension, variation, arithmetic average height, and the like of the covering portion 7 within a predetermined range. Hereinafter, the knowledge obtained by the inventor regarding the covering portion 7 will be described.

  The material of the covering portion 7 is preferably a resin having corrosion resistance such as polyimide resin or fluororesin. In particular, a polyimide resin is more preferable because it is excellent in corrosion resistance and can be formed into a film having excellent coating properties by a vapor deposition polymerization method described later. In this case, at least a polyimide resin may be included.

The volume resistivity at 25 ° C. of the covering portion 7 is preferably 10 ¹⁴ Ωcm or more and 10 ¹⁸ Ωcm or less. If it is less than 10 ¹⁴ Ωcm, current flows to the object to be processed through the covering portion 7, so that the Johnsen-Rahbek force increases, the residual adsorption force increases, and the detachment response may deteriorate. Moreover, it is because it becomes unnecessary to select a special material and a manufacturing method by setting it as 10 < ¹⁸ > ohm-cm or less, and it becomes possible to select a general and economical polyimide manufacturing method.

  It is preferable that the thickness dimension of the coating | coated part 7 shall be 2 micrometers or more and 15 micrometers or less. Here, the surface shape of the base layer is transferred to the surface of the covering portion 7 formed thereon, and the thickness of the covering portion 7 is more easily affected by the reduction in thickness. For this reason, if the thickness is less than 2 μm, the influence of the base is greatly affected, and it may be difficult to reduce the arithmetic average height in the polishing process (finishing process) after film formation. Moreover, it is because there exists a possibility that film | membrane intensity | strength may become small and peeling may generate | occur | produce. On the other hand, if the thickness exceeds 15 μm, the attractive force may be too small.

  The variation in the thickness dimension of the covering portion 7 is preferably ± 10% or less. This is because if it exceeds ± 10%, the dispersion of the adsorption force becomes large and the in-plane distribution of the adsorption force becomes too large. Such uniform film formation can be performed by, for example, a vapor deposition polymerization method or a CVD (Chemical Vapor Deposition) method.

  The arithmetic average height of the surface of the covering portion 7 (contact surface with the object to be processed) formed on the top surface of the protrusion 3a is smaller than the arithmetic average height of the surface of the covering portion 7 formed on the flat surface portion 3b. It has become. In this case, the arithmetic average height Ra of the surface of the covering portion 7 formed on the top surface of the protruding portion 3a is preferably 0.01 μm or more and 0.1 μm or less. This is because if the thickness is less than 0.01 μm, the time required for polishing (finishing) becomes longer and the productivity is remarkably reduced. On the other hand, if it exceeds 0.1 μm, a chip pocket may be formed in this portion. This is because when the polishing process (finishing process) is performed, fine particles enter the chip pocket, and the particles are discharged later, thereby causing particle contamination. In addition, “arithmetic average height Ra” in the present specification is based on “JIS B0601: 2001”.

  Moreover, it is preferable that arithmetic mean height Ra of the surface of the coating | coated part 7 formed in the plane part 3b shall be 1 micrometer or less. If the thickness exceeds 1 μm, fine particles generated when the covering portion 7 formed on the top surface of the protrusion 3a is polished may enter the chip pocket formed in this portion. This is because there is a possibility that particle contamination is caused by the later release of the particles.

Next, the protrusion 3a will be further described.
The cross section in the direction substantially parallel to the flat surface portion 3b of the protruding portion 3a can be an arbitrary shape. However, if the shape has no corners, such as a circle, cracks and chips can be suppressed.

Moreover, when making the protrusion part 3a into a substantially cylindrical shape, it is preferable that a diameter shall be 0.1 mm or more and 1.0 mm or less. This is because if the thickness is less than 0.1 mm, it is difficult to form the protrusion 3a. On the other hand, if the thickness exceeds 1.0 mm, the total contact area with the object to be processed becomes too large, which may increase particle contamination due to rubbing and deterioration of detachment response.
When the diameter of the protrusion 3a is 1.0 mm and the thickness of the cover is 10 μm, the diameter of the cover 7 that covers the protrusion 3a is 1.02 mm.

  Moreover, it is preferable that the dimension from the surface of the coating | coated part 7 formed in the top face of the projection part 3a to the plane part 3b shall be 5 micrometers or more and 15 micrometers or less. This is because if the thickness is less than 5 μm, there is a possibility that the surface on the side where the processing object is placed and the portion where the flat portion 3b is exposed come into contact when the processing object is adsorbed. On the other hand, if the thickness exceeds 15 μm, the space coulomb force described later is weakened, so that the adsorption force may be insufficient.

  The arrangement pitch dimension of the protrusions 3a is preferably 2 mm or more and 15 mm or less. This is because if the thickness is less than 2 mm, the total contact area with the object to be processed becomes too large, which may increase particle contamination due to rubbing and deteriorate detachment response. On the other hand, if the thickness exceeds 15 mm, there is a possibility that the surface on which the processing object is placed and the portion where the flat surface portion 3b is exposed come into contact when the processing object is adsorbed.

  In addition, the height of the protrusion 3a, the arrangement pitch dimension of the protrusion 3a, the thickness of the cover 7 and the area where the flat surface 3b is covered with the cover 7 around the protrusion 3a The size range is set so that the surface of the workpiece to be placed and the surface of the portion formed on the flat surface portion 3b of the covering portion 7 do not come into contact with each other when sucked.

The contact area ratio between the surface of the covering portion on the top surface of the protrusion 3a and the object to be processed is preferably 0.005% or more and 1.5% or less. If the content is less than 0.005%, it is difficult to form the protrusion 3a, and when the workpiece is adsorbed, the projection 3a is formed on the surface on the placement side of the workpiece and the flat portion 3b of the covering portion 7. This is because there is a risk of contact with the surface of the part. On the other hand, if it exceeds 1.5%, the total contact area with the object to be processed becomes too large, so that there is a possibility that the particle contamination increases due to rubbing and the detachment response deteriorates.
Note that the calculation of the contact area ratio between the protrusion 3a and the object to be processed does not include the area of the ring-shaped protrusion described above.

Next, the base of the covering portion 7 will be described.
The base of the covering portion 7, that is, the surfaces of the protrusion 3a and the flat portion 3b has a great influence on the arithmetic average height and adhesion (peelability) of the covering portion 7 formed thereon. Therefore, it is important that the arithmetic average heights of the protrusion 3a and the flat surface 3b are within a predetermined range. Hereinafter, the knowledge obtained by the present inventor regarding the base of the covering portion 7 will be described.

  The arithmetic average height Ra on the top surface of the protrusion 3a is preferably 0.15 μm or more and 0.30 μm or less. This is because if the thickness is less than 0.15 μm, the adhesion of the covering portion 7 formed on the top surface of the protruding portion 3a may be reduced, and peeling may occur. Further, the surface shape of the underlayer is transferred to the surface of the covering portion 7 formed thereon. Therefore, if the thickness exceeds 0.30 μm, the unevenness formed on the surface of the covering portion 7 will be increased accordingly, and the time required to obtain a smooth surface (polishing time for finishing) will become longer and the productivity will be increased. This is because remarkably decreases.

  From the viewpoint of improving the adhesion (peelability), it is preferable to make the arithmetic average height of the flat surface portion 3b at least larger than the arithmetic average height of the top surface of the protruding portion 3a. In this case, it is preferable that the arithmetic average height Ra of the planar portion 3b is 0.15 μm or more and 1.0 μm or less. This is because if the thickness is less than 0.15 μm, the adhesion of the covering portion 7 formed on the flat surface portion 3b may be reduced and peeling may occur.

  On the other hand, if processing is performed on which a surface exceeding 1.0 μm is formed, the dimensional accuracy of the protrusion 3a may be deteriorated. For example, it is necessary to use an abrasive having a larger particle diameter than usual in order to form the flat surface portion 3b using a sandblasting method described later and to make the arithmetic average height Ra exceed 1.0 μm. Therefore, it is difficult to control the dimensions when forming the protrusions 3a, and the height dimension accuracy may be deteriorated.

Next, the operation of the electrostatic chuck 1 according to the present embodiment will be described.
An object to be processed (for example, a semiconductor wafer) is placed on the surface (mounting surface) of the covering portion 7 formed on the top surface of the protruding portion 3a, and a voltage is applied to the electrode 4 by the power source 10a and the power source 10b. . At this time, charges having different polarities are generated between the object to be processed and the vicinity of the top surface of the protrusion 3a, and the object to be processed is adsorbed and fixed by the Coulomb force acting between the charges. Further, since the space 3c is formed above the plane portion 3b, charges having different polarities are generated in the plane portion 3b and the object to be processed thereabove, and the Coulomb force (space Coulomb force) acting between the charges is generated. The object to be processed is fixed by suction. That is, the electrostatic chuck 1 attracts and fixes the object to be processed by the Coulomb force generated in the protruding portion 3a and the space Coulomb force generated in the flat portion 3b.

  In this case, in the portion where the Coulomb force is generated (protrusion portion 3a portion), the object to be processed and the covering portion 7 come into contact with each other, so that particles may be generated. Therefore, in the present embodiment, the generation of particles is suppressed by setting the arithmetic average height of the surface of the covering portion 7 as described above. Moreover, since the thickness dimension of the coating | coated part 7 is settled in the predetermined range mentioned above, the dispersion | variation in adsorption | suction force is reduced.

Further, in the portion where the space Coulomb force is generated (the portion of the space 3c formed above the flat surface portion 3b), the object to be processed and the flat surface portion 3b or the covering portion 7 do not come into contact with each other. There is no. Therefore, the occurrence of particle contamination can be greatly reduced by increasing the number of portions where the space Coulomb force is generated.
Further, in the electrostatic chuck 1 according to the present embodiment, the portion where the space Coulomb force is generated is increased, and the object to be processed is prevented from being bent and coming into contact with the flat portion 3b or the covering portion 7. As described above, the height dimension, the arrangement pitch dimension, the diameter dimension, the contact area ratio between the surface of the covering part and the object to be processed at the top surface of the projection part 3a, and the like are set. Moreover, these conditions regarding the protrusion part 3a are also conditions under which an appropriate attractive force can be obtained even if the portion where the space coulomb force is generated is increased. The particle reduction effect will be described later (see Table 2).

Further, as described above, since the portion covered with the covering portion 7 is limited to a necessary range, the amount of remaining charges can be suppressed. Therefore, the detachment response of the object to be processed can be improved, and a stable adsorption force can be obtained.
Further, the portion to which the external force is applied is separated from the end portion of the covering portion 7 which is likely to be peeled due to manufacturing. Therefore, even when an external force (external force acting in the peeling direction) that pulls the covering portion 7 in the vicinity of the top surface of the protruding portion 3a is generated when the workpiece is adsorbed and separated, the end portion of the covering portion 7 Can reduce the external force (external force acting in the peeling direction) that pulls the end of the covering portion 7 upward. As a result, the occurrence and progress of peeling can be suppressed.
Further, the end portion of the covering portion 7 that may cause burrs and burrs in production is provided at a position separated from the surface on which the workpiece is placed. For this reason, even if there are burrs and burrs at the end of the covering portion 7, it is possible to prevent the burrs and burrs from touching the surface on which the workpiece is placed. As a result, it is possible to suppress damage to the surface on the placement side of the object to be processed and increase in the number of particles.

  In the processing of the workpiece, the temperature of the workpiece may be controlled via the electrostatic chuck 1 in some cases. In the electrostatic chuck 1 according to the present embodiment, the temperature of the object to be processed can be controlled by flowing a cooling liquid or a heating liquid through the flow path 8. For convenience of explanation, the case where the temperature control is performed by flowing the cooling liquid or the heating liquid is illustrated, but other temperature control means such as a heater may be provided.

  Further, a gas (for example, helium gas) supplied from a gas supply unit (not shown) is adjusted in pressure and flow rate by a pressure control unit and a flow rate control unit (not shown), and then passes through the through hole 11 and above the flat portion 3b. Introduced into the space 3c formed. The introduced gas passes through the space 3c and spreads throughout. And since the thermal conductivity is remarkably increased by the introduced gas, it is possible to effectively heat and cool the workpiece.

In addition, ring-shaped protrusions are arranged in a ring shape around the outer peripheral portion of the mounting surface of the object to be processed such as a semiconductor wafer and through holes other than those for gas introduction so that the aforementioned gas does not leak out. You can also
Furthermore, by providing a gas distribution groove (concave groove) (not shown) that is provided radially and concentrically on the flat portion 3b and communicates with the through hole 11, the gas distribution speed can be increased.
In addition, you may make it form the coating | coated part 7 in the inside of the gas distribution groove | channel which is not shown in figure. If the covering portion 7 is formed inside the gas distribution groove, an effect of preventing discharge between the object to be processed and the flat portion 3b can be expected.

表２からわかるように、本実施の形態に係る静電チャック１によればパーティクルの発生数を低減させることができる。例えば、特許文献１（特開２００６−２８７２１０号公報）において開示がされたものと比較すると、突起を有する静電チャックにおいて、突起の頂面だけを被覆部で覆ったもの（特許文献１の図２（ａ）のもの）の場合では５０００個程度、全面を被覆部で覆ったもの（特許文献１の図１（ａ）のもの）の場合では１０００個であったパーティクル数を、本発明の形態に係る静電チャック１では、７４０個と低減させることができた。 Next, the results of various measurements performed by the inventor will be described.
Table 2 is a table for illustrating the measurement result of the number of particles.

As can be seen from Table 2, according to the electrostatic chuck 1 according to the present embodiment, the number of particles generated can be reduced. For example, in comparison with the one disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2006-287210), in an electrostatic chuck having a protrusion, only the top surface of the protrusion is covered with a covering portion (see FIG. 1 of FIG. 1). 2 (a)), the number of particles was about 5000, and in the case of the case where the entire surface was covered with a covering (FIG. 1 (a) in Patent Document 1), the number of particles was 1000. In the electrostatic chuck 1 according to the embodiment, the number could be reduced to 740.

  In Table 2, as a comparative example, the number of particles generated in an electrostatic chuck without a coating portion (not coated with resin) is shown. In an electrostatic chuck without a covering portion, the number of particles is 3055, and it can be seen that the electrostatic chuck 1 in the present embodiment has a smaller number of generated particles than such an electrostatic chuck.

表３からわかるように、サンドブラスト法を用いて平面部３ｂを形成させるようにすれば、平面部３ｂの算術平均高さＲａを前述した範囲内（０．１５μｍ以上、１．０μｍ以下）に収めることができる。 Table 3 is a table for illustrating the arithmetic average height of the flat surface portion 3b formed using the sandblast method.

As can be seen from Table 3, when the plane portion 3b is formed using the sand blast method, the arithmetic average height Ra of the plane portion 3b falls within the above-described range (0.15 μm or more and 1.0 μm or less). be able to.

表４からわかるように、下地の算術平均高さを０．１５μｍ以上とすれば、良好な密着強度を得ることができる。また、算術平均高さを大きくするほど密着強度を大きくすることができることもわかる。また、前述したように下地の表面形状はその上に形成される被覆部７の表面に転写されるので、算術平均高さを大きくしすぎると平滑面を得るために要する時間（ポリッシュ加工時間）が長くなりすぎることがわかる。 Table 4 is a table for illustrating the relationship between the arithmetic average height Ra of the base, the adhesion strength of the base-covering portion, and the polishing time performed after the coating portion is formed (after resin coating). .

As can be seen from Table 4, when the arithmetic average height of the base is 0.15 μm or more, good adhesion strength can be obtained. It can also be seen that the adhesion strength can be increased as the arithmetic average height is increased. Further, as described above, since the surface shape of the base is transferred to the surface of the covering portion 7 formed thereon, the time required to obtain a smooth surface when the arithmetic average height is excessively increased (polishing time) It turns out that becomes too long.

  Table 5 shows the arithmetic average height Ra of the covering portion 7 immediately after film formation formed on the top surface of the protrusion 3a and the arithmetic average height of the covering portion 7 formed on the top surface of the protrusion 3a after polishing. It is a table | surface for exemplifying Sa.

表５からわかるように、ポリッシュ加工を行えば突起部３ａの頂面に形成された被覆部７表面（被処理物との接触面）の算術平均高さＲａを前述した範囲内（０．０１μｍ以上、０．１μｍ以下）に収めることができる。

As can be seen from Table 5, if the polishing process is performed, the arithmetic average height Ra of the surface of the covering portion 7 (contact surface with the object to be processed) formed on the top surface of the protrusion 3a is within the above-mentioned range (0.01 μm). As described above, it can be within 0.1 μm or less.

表６からわかるように、突起部３ａの配設ピッチを前述した範囲内（２ｍｍ以上、１５ｍｍ以下）に収めれば、吸着力が大きい場合においても被処理物（半導体ウェーハ）の撓み量（１．５５μｍ以下）を前述した突起部３ａの高さ寸法（２μｍ以上、１５μｍ以下）より小さくすることができる。そのため、被処理物の載置側の面と平面部３ｂに形成された被覆部７の表面との接触を防止することができる。 Table 6 is a table for illustrating the relationship between the suction force and the bending of the workpiece (semiconductor wafer) when the arrangement pitch of the protrusions 3a is changed.

As can be seen from Table 6, if the arrangement pitch of the protrusions 3a is within the above-mentioned range (2 mm or more and 15 mm or less), the amount of deflection (1) of the workpiece (semiconductor wafer) even when the adsorption force is large. .55 μm or less) can be made smaller than the height dimension (2 μm or more and 15 μm or less) of the projection 3 a described above. Therefore, it is possible to prevent contact between the surface of the object to be processed and the surface of the covering portion 7 formed on the flat surface portion 3b.

Next, the manufacturing method of the electrostatic chuck 1 according to the present embodiment will be illustrated.
FIG. 3 is a flowchart for illustrating the method of manufacturing the electrostatic chuck.
First, a method for forming the dielectric substrate 3 will be illustrated.

First, for example, an alumina raw material powder having an average particle diameter of 0.1 μm and a purity of 99.99% or more is used as a raw material, and this is mixed and pulverized with titanium oxide (TiO ₂ ) exceeding 0.2 wt% and 0.6 wt% or less. Then, an acrylic binder is added, adjusted, and granulated with a spray dryer to produce granulated powder.

Next, after forming CIP (rubber press) or mechanical press, it is processed into a predetermined shape and fired in a reducing atmosphere of 1150 ° C to 1350 ° C. Thereafter, HIP processing (hot isostatic pressing) is performed. The conditions for the HIP treatment are Ar gas of 1000 atm or higher, and the temperature is 1150 ° C. to 1350 ° C. which is the same as the firing temperature. According to such conditions, the relative density is extremely dense as 99% or more, the average particle diameter of the constituent particles is 2 μm or less, and the volume resistivity is 10 ⁸ to 10 ¹¹ Ωcm at 20 ± 3 ° C., the thermal conductivity. A dielectric substrate 3 having a thickness of 30 W / mK or more is obtained (step 1).

  In addition, the average particle diameter here is a particle diameter obtained by the following planimetric method. First, a picture of the dielectric substrate 3 is taken with a scanning electron microscope (SEM), a known circle with an area A is drawn on this photograph, and the number of particles in the circle nc and the particles that are covered by the circumference The number of particles per unit area NG is obtained from the number ni by the following equation (1).

  M shown here is the magnification of the photograph. Since 1 / NG is the area occupied by one particle, the average particle diameter can be obtained by the following equation (2) of the equivalent circle diameter.

  Next, after grinding one main surface of the dielectric substrate 3, a conductive film made of the aforementioned titanium or titanium compound is formed by a CVD (Chemical Vapor Deposition) method, a PVD (Physical Vapor Deposition) method, or the like, The formed film is formed into a predetermined shape by a sandblasting method or an etching method, thereby forming an electrode 4 having a desired shape (step S2). An electric wire 9 is appropriately wired to the electrode 4.

  Next, the protruding portion 3a and the flat portion 3b are formed on the main surface on the side opposite to the main surface on which the electrodes of the dielectric substrate 3 are provided by using a sand blasting method (step S3).

  In the formation of the protruding portion 3a and the flat portion 3b, first, the main surface of the dielectric substrate 3 is polished, a resist film is attached to the surface, and a mask having a desired shape is formed by performing photosensitivity and removal. (Step S3a). That is, the portion where the flat portion 3b is formed is exposed without a mask, and the portion where the projection 3a is formed is covered with the mask.

  In addition, by polishing the main surface of the dielectric substrate 3, the arithmetic average height Ra is set to 0.15 μm or more and 0.30 μm or less. As will be described later, since the portion covered with the mask becomes the top surface of the protrusion 3a, the arithmetic average height of the top surface of the protrusion 3a is within the above-described range (Ra is 0.15 μm or more and 0.30 μm or less). Can be.

Next, a portion of the main surface of the dielectric substrate 3 that is not covered by the mask is removed using a sandblast method (step S3b). In this case, the portion that has been removed becomes the flat surface portion 3b, and the portion that has not been removed because it is covered with the mask becomes the projection portion 3a.
Thus, if the protrusion 3a and the flat surface 3b are formed by the sandblast method, the dimensional accuracy of the height of the protrusion 3a can be improved. Therefore, since the variation in the dimension from the plane part 3b to a to-be-processed object can be suppressed, the variation in the electrostatic force (space Coulomb force) to express can be suppressed.

  In addition, by forming the flat portion 3b by the sand blast method, the arithmetic average height is within the above-described range (Ra is 0.15 μm or more and 1.0 μm or less) as shown in Table 3. Can do. In this case, the arithmetic average height of the flat surface portion 3b is set to be at least larger than the arithmetic average height of the top surface of the protrusion 3a.

Next, the mask is removed (step S3c).
In addition, you may make it remove the edge of the top part of the projection part 3a as needed.

Next, the resin is coated so as to cover the protrusion 3a and the flat portion 3b (step S4).
This coated resin becomes the covering portion 7.
The material of the resin can be, for example, a polyimide resin. In addition, it can also contain a polyimide resin at least. Further, the thickness dimension of the coated resin is set to 5 μm or more and 15 μm or less. In this case, various film forming methods such as a vapor deposition polymerization method, a CVD (Chemical Vapor Deposition) method, and a spin coating method can be used for coating the resin. However, it is preferable to use a vapor deposition polymerization method, a CVD (Chemical Vapor Deposition) method or the like in order to make the variation in the thickness dimension of the coated resin ± 10% or less.

Next, it finishes so that the surface (contact surface with a to-be-processed object) of resin coat | covered on the top face of the projection part 3a may become smooth (step S5).
In this case, the top surface of the protrusion 3a is coated so that the arithmetic average height of the resin surface coated on the top surface of the protrusion 3a is smaller than the arithmetic average height of the resin surface coated on the flat surface 3b. The surface of the resin is processed.
At this time, the arithmetic average height of the resin surface coated on the top surface of the protrusion 3a is set within the above-described range (Ra: 0.01 μm or more, 0.1 μm or less). For example, such arithmetic average height can be obtained by polishing.

Next, the covering portion 7 is formed by cutting and removing the resin covered by the flat portion 3b (step S6). That is, a part of the resin coated on the upper surface of the flat part 3b is cut, and the cut resin is removed to form the covering part 7.
In this case, the resin can be cut using a laser processing method or a water jet processing method.
For example, the YAG laser is irradiated to the boundary portion of the portion to be removed, and the coated resin is cut. Then, the coating | coated part 7 is formed by removing the resin of the part which becomes unnecessary. At this time, if the resin is cut using a YAG laser, the generation of burrs and burrs can be suppressed, so that the quality of the end portion of the covering portion 7 can be improved.
Moreover, you may make it use the water jet processing method etc. for the cutting | disconnection of resin covered.

On the other hand, the base 2 provided with the flow path 8 is created by cutting or the like, and the insulator layer 5 is formed on one main surface of the base 2 (step S7).
In this case, the insulator layer 5 can be formed on the entire surface of the base 2. Moreover, what is necessary is just to provide the flow path 8 as needed.
The insulator layer 5 can be formed using a thermal spraying method, an aerosol deposition method, or the like.

Next, the main surface of the dielectric substrate 3 on which the electrode 4 is provided and the main surface on which the insulator layer 5 of the base 2 is provided are joined using an insulating adhesive (step S8).
At this time, the electric wire 9 is passed through the base 2 so that the electrode 4 and the power source 10 a and the power source 10 b can be connected by the electric wire 9. The bonding layer 6 is obtained by curing the insulating adhesive.

Next, the surface of the covering portion 7 is cleaned as necessary (step S9).
In this case, for example, ultrasonic cleaning using IPA (Isopropyl Alcohol) is performed after cleaning using a neutral detergent, and then ultrasonic cleaning using ultrapure water is performed. Can do.
As described above, the electrostatic chuck 1 according to the present embodiment can be manufactured.

  FIG. 4 is a schematic cross-sectional view for illustrating an electrostatic chuck according to another embodiment of the present invention, and FIG. 5 is for illustrating a specific example of the method for manufacturing the electrostatic chuck shown in FIG. It is a flowchart of.

  4A is a schematic cross-sectional view for illustrating the electrostatic chuck 1a, and FIG. 4B is a schematic enlarged view of a portion C in FIG. 4A.

  The procedure for forming the protrusion 3a and the flat surface 3b is different from that described with reference to FIG. That is, after the insulator layer 5 and the dielectric substrate 3 are joined, the protrusion 3a and the flat portion 3b are formed on the upper surface of the dielectric substrate 3 (the main surface opposite to the main surface on which the electrodes are provided) by sandblasting. Like that.

Specifically, the dielectric substrate 3 is formed from the raw material through molding, firing, and HIP processing (step S11) in the same manner as in step S1 of FIG. 3, and the dielectric substrate is formed in the same manner as in step S2 of FIG. An electrode is formed on one main surface of No. 3 (step S12).
On the other hand, the insulator layer 5 is formed (step S13).
Then, similarly to step S8 of FIG. 3, the main surface of the dielectric substrate 3 on which the electrode 4 is provided and the main surface of the insulator layer 5 are joined using an insulating adhesive (step S14). .

Next, in the same manner as in step S3a of FIG. 3, the main surface of the dielectric substrate 3 opposite to the main surface provided with the electrode 4 is polished, a resist film is attached to the surface, and the surface is exposed to light. A mask having a desired shape is formed (step S15a).
Next, similarly to step S3b of FIG. 3, the portion not covered with the mask is removed using the sandblast method (step S15b).

  Next, the mask is removed in the same manner as in step S3c in FIG. 3 (step S15c).

Next, in the same manner as in step S4 of FIG. 3, the resin is coated so as to cover the protrusion 3a and the flat portion 3b (step S16).
Next, in the same manner as in step S5 in FIG. 3, the surface of the resin coated on the top surface of the protrusion 3a (contact surface with the object to be processed) is finished to be smooth (step S17).
Next, similarly to step S6 of FIG. 3, the coated resin 7 is cut and removed to form the coated portion 7 (step S18).

Next, as in step S9 in FIG. 3, the surface of the covering 7 is cleaned as necessary (step S19).
The contents in each procedure are the same as those illustrated in FIG.

  DESCRIPTION OF SYMBOLS 1 Electrostatic chuck, 1a Electrostatic chuck, 2 bases, 3 dielectric substrate, 3a protrusion part, 3b plane part, 3c space, 3d position, 4 electrode, 5 insulator layer, 6 bonding layer, 7 coating | coated part, 8 Flow path, 9 wires, 10a power supply, 10b power supply, 11 through hole

Claims (9)

A dielectric substrate having a plurality of protrusions formed on the main surface on the side on which the workpiece is placed, and a flat surface formed around the plurality of protrusions;
A covering portion formed to cover the plurality of protrusions and the planar portion;
An electrostatic chuck comprising:
The volume resistivity at 25 ° C. of the covering portion is 10 ¹⁴ Ωcm or more and 10 ¹⁸ Ωcm or less,
A region where the covering portion is not formed on the flat portion is provided in a partial region on the flat portion between the plurality of protrusions , thereby suppressing the amount of charge remaining on the covering portion. An electrostatic chuck characterized by comprising:
The covering portion is formed in a range of a thickness dimension of the covering portion to 3 mm or less in a direction away from the protruding portion from a position where the side surface of the protruding portion and the flat portion intersect on the flat portion. The electrostatic chuck according to claim 1. 3. The electrostatic chuck according to claim 1, wherein a volume resistivity of the dielectric substrate in an operating temperature region of the electrostatic chuck is 10 ⁹ Ωcm or more and 10 ¹¹ Ωcm or less. The covering portion, the electrostatic chuck according to any one of claims 1-3, characterized in that it comprises a polyimide resin. The covering portion, the electrostatic chuck according to any one of claims 1-4, characterized in that, formed by a vapor deposition polymerization method. Contact area ratio between the surface and the object to be treated of the covering portion which is covered on the top surface of the protrusion, 0.005% or more, according to claim 1-5, characterized in, it is 1.5% or less The electrostatic chuck according to any one of the above. The main surface of the dielectric substrate opposite to the main surface on which the electrodes are provided is polished, a mask having a desired shape is provided on the main surface, and a portion not covered with the mask is removed using a sand blast method. To form a flat part and a protrusion,
A resin is coated so as to cover the protrusion and the flat portion,
The top surface of the protrusion so that the arithmetic average height of the surface of the resin coated on the top surface of the protrusion is smaller than the arithmetic average height of the surface of the resin coated on the top surface of the flat portion. Polishing the surface of the resin coated on
Cutting a part of the resin coated on the upper surface of the flat part,
An electrostatic chuck characterized in that, by removing the cut resin, a covering portion provided with a region where the resin is not formed is formed to suppress the amount of electric charge remaining on the resin . Production method.

The method of manufacturing an electrostatic chuck according to claim 7 , wherein the resin is coated using a vapor deposition polymerization method. The resin production method of an electrostatic chuck according to claim 7 or 8 being cut using a laser processing method or water jet processing method, characterized by.

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