JP5515365B2 - Electrostatic chuck and method of manufacturing electrostatic chuck - Google Patents

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, when the mounting surface of the electrostatic chuck and the object to be processed rub against each other, particles may be generated. In this case, an electrostatic chuck capable of expressing a strong attracting force such as a Johnsen-Rahbek type electrostatic chuck is more likely to generate particles. In addition, the adsorption / desorption response of the object to be processed may be deteriorated.

  Therefore, an electrostatic chuck has been proposed in which a protrusion is provided on the mounting surface side of the electrostatic chuck to reduce the contact area, thereby suppressing particle contamination and improving the adsorption / desorption response of the workpiece. Yes. In addition, a technique for further suppressing generation of particles and scratches by covering the mounting surface of the electrostatic chuck with a resin layer has been proposed (see Patent Document 1).

  However, in the technique disclosed in Patent Document 1, no consideration is given to the base of the resin layer, and the surface roughness at the contact portion with the object to be processed (the surface of the resin layer on the top surface of the protrusion) increases. There is a possibility that a chip pocket (fine concave portion) 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. Further, depending on the surface roughness of the base of the resin layer, there is a possibility that the adhesion of the resin layer may be reduced.

  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, in the technique disclosed in Patent Document 2, no consideration is given to the foundation of the resin layer. Similar to the technique disclosed in Patent Document 1, the occurrence of particle contamination and the surface roughness of the foundation of the resin layer. There was a possibility that the adhesion of the resin layer may be reduced due to the above.

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

  An aspect of the present invention has been made on the basis of recognition of such a problem, can greatly suppress the occurrence of particle contamination, and adheres to the resin layer formed on the mounting surface side of the electrostatic chuck. An electrostatic chuck having a high force and a method for manufacturing the electrostatic chuck are provided.

According to one aspect of the present invention, possess a protrusion formed on the main surface on the side for placing an object to be processed, and a flat portion formed around the protruding portion, a ceramic sintered body a dielectric substrate that Do, and the protrusion, the a plane portion, and a resin layer formed so as to cover the, an electrostatic chuck having a volume resistivity at 25 ° C. of the resin layer, 10 ¹⁴ Ωcm or more, and the surface roughness of the top surface of the protrusion that is the base of the resin layer is smaller than the surface roughness of the flat portion, and the surface of the top surface of the protrusion that is the base of the resin layer The roughness is 0.06 μm or more and 0.3 μm or less in terms of arithmetic average roughness Ra, and the surface roughness of the planar portion that is the base of the resin layer exceeds 0.06 μm in terms of arithmetic average roughness Ra, An electrostatic chuck characterized by being 0.7 μm or less is provided.

According to another aspect of the present invention, the main surface of the dielectric substrate made of a ceramic sintered body on the side on which the workpiece is placed is polished, and a mask having a desired shape is provided on the main surface. By removing a portion not covered by the mask using a sandblast method, a flat portion is formed and a protrusion is formed, and a resin is coated so as to cover the protrusion and the flat portion. A method of manufacturing an electrostatic chuck that forms a resin layer and polishes the surface of the resin layer formed on the top surface of the protrusion, wherein when forming the flat portion and the protrusion, When the surface roughness of the top surface of the protrusion is made smaller than the surface roughness of the flat surface portion and the main surface is polished, the surface roughness of the main surface is 0.06 μm in terms of arithmetic average roughness Ra. As described above, it is formed by being 0.3 μm or less. The surface roughness of the top surface of the protrusion is such that the arithmetic average roughness Ra is 0.06 μm or more and 0.3 μm or less, and the surface roughness of the planar portion is arithmetic when forming the planar portion. There is provided an electrostatic chuck manufacturing method characterized in that the average roughness Ra is more than 0.06 μm and not more than 0.7 μm .

  According to the aspects of the present invention, the occurrence of particle contamination can be significantly suppressed, and the adhesion of the resin layer formed on the mounting surface side of the electrostatic chuck is high. A manufacturing method is provided.

1 is a schematic cross-sectional view for illustrating an electrostatic chuck according to an embodiment of the present invention. It is a graph for demonstrating the relationship between the surface roughness of a foundation | substrate, and adhesive force. 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. 5 is a flowchart for illustrating a method of manufacturing the electrostatic chuck illustrated in FIG. 4.

Embodiment of the first invention, possess a protrusion formed on the main surface on the side for placing an object to be processed, and a flat portion formed around the protruding portion, a ceramic sintered body a dielectric substrate that Do, and the protrusion, the a plane portion, and a resin layer formed so as to cover the, an electrostatic chuck having a volume resistivity at 25 ° C. of the resin layer, 10 ¹⁴ Ωcm or more, and the surface roughness of the top surface of the protrusion that is the base of the resin layer is smaller than the surface roughness of the flat portion, and the surface of the top surface of the protrusion that is the base of the resin layer The roughness is 0.06 μm or more and 0.3 μm or less in terms of arithmetic average roughness Ra, and the surface roughness of the planar portion that is the base of the resin layer exceeds 0.06 μm in terms of arithmetic average roughness Ra, The electrostatic chuck is characterized by being 0.7 μm or less .
According to this electrostatic chuck, the occurrence of particle contamination can be greatly suppressed, and the adhesion of the resin layer formed on the mounting surface side of the electrostatic chuck can be increased.
According to this electrostatic chuck, it is possible to prevent the processing time (such as polishing time for finishing) from being prolonged so that the surface roughness of the resin layer formed on the top surface of the protrusion is within a predetermined range. can do.
According to this electrostatic chuck, since the adhesive force is small, it is possible to suppress the resin layer from peeling off.
According to this electrostatic chuck, it is possible to suppress an increase in the Johnsen-Rahbek force due to the current flowing through the workpiece through the resin layer. As a result, it is possible to prevent the residual adsorption force from increasing and the adsorption / desorption response from deteriorating.

In addition, in the embodiment of the second invention, in the embodiment of the first invention, the surface roughness of the resin layer formed on the top surface of the protrusion is 0.01 μm or more in terms of arithmetic average roughness Ra, The electrostatic chuck is characterized by being 0.1 μm or less .
Further, according to this electrostatic chuck, it is possible to reduce the polishing (finishing) time after the formation of the resin layer. In addition, since the formation of chip pockets (fine concave portions) can be suppressed, the occurrence of particle contamination can be suppressed.

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 prevent the current value at the time of voltage application from becoming too large. Moreover, it can suppress that adsorption-desorption responsiveness deteriorates.

An embodiment of the fourth invention is an electrostatic chuck according to any one of the first to third inventions, wherein the resin layer includes a polyimide resin.
According to this electrostatic chuck, it is possible to have a resin layer having excellent corrosion resistance and excellent coating properties by vapor deposition polymerization or the like.

An embodiment of a fifth invention is the electrostatic chuck according to any one of the first to fourth inventions, wherein the resin layer is formed using a vapor deposition polymerization method. It is.
According to this electrostatic chuck, the resin layer having excellent coating characteristics can be provided.

In addition, according to an embodiment of the sixth invention, in the embodiment of any one of the first to fifth inventions, a contact area ratio between the protrusion and the object to be processed is 0.005% or more and 1.5%. The electrostatic chuck is characterized by the following.
According to this electrostatic chuck, it is possible to facilitate the formation of the protrusions by the sandblast method or the like. Further, when the object to be processed is adsorbed, it is possible to prevent the surface of the object to be processed from contacting the surface of the resin layer formed on the surface of the flat portion. Further, it is possible to suppress an increase in particle contamination due to rubbing and a deterioration in adsorption / desorption response.

Further, an embodiment of the seventh invention is a sand blasting method in which a principal surface on a side of placing a workpiece of a dielectric substrate made of a ceramic sintered body is polished, and a mask having a desired shape is provided on the principal surface. The resin layer is formed by forming a flat portion by removing a portion not covered with the mask using a mask and forming a protrusion, and covering the protrusion and the flat portion with a resin. And manufacturing the electrostatic chuck for polishing the surface of the resin layer formed on the top surface of the protrusion, wherein the protrusion is formed when the flat portion and the protrusion are formed. When the main surface is polished, the surface roughness of the main surface is 0.06 μm or more in terms of arithmetic average roughness Ra. Before being formed by making it 0.3 μm or less When the surface roughness of the top surface of the projection is 0.06 μm or more and 0.3 μm or less in terms of arithmetic average roughness Ra, the surface roughness of the planar portion is the arithmetic average when forming the planar portion. A method for producing an electrostatic chuck, characterized in that the roughness Ra is more than 0.06 μm and not more than 0.7 μm .
According to this method for manufacturing an electrostatic chuck, an electrostatic chuck that can greatly suppress the occurrence of particle contamination and has a high adhesion force to a resin layer formed on the mounting surface side of the electrostatic chuck is manufactured. can do.
According to this method for manufacturing an electrostatic chuck, the time required for processing so that the surface roughness of the resin layer formed on the top surface of the protrusions is within a predetermined range (such as polishing time for finishing) becomes longer. This can be suppressed.
According to this method for manufacturing an electrostatic chuck, it is possible to prevent the resin layer from being peeled off because the adhesion force is small.

Further, according to an eighth aspect of the present invention, in the seventh aspect of the present invention, the surface roughness of the surface of the resin layer formed on the top surface of the protrusion is arithmetic when performing the polishing process. An electrostatic chuck manufacturing method characterized in that an average roughness Ra is 0.01 μm or more and 0.1 μm or less.
According to this method for manufacturing an electrostatic chuck, the polishing (finishing) time after the formation of the resin layer can be reduced. In addition, it is possible to suppress the formation of chip pockets (fine concave portions).

An ninth embodiment of the present invention is the method for manufacturing an electrostatic chuck according to the seventh or eighth embodiment, wherein the resin layer is formed using a vapor deposition polymerization method. . According to this method of manufacturing an electrostatic chuck, a resin layer having excellent coating characteristics can be formed.

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 A 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 (mounting surface side) on which the object to be processed is placed, and a flat surface portion 3b formed around the protrusion 3a. doing. Moreover, the resin layer 7 is formed so that the projection part 3a and the plane part 3b may be covered. The surface of the resin layer 7 on the top surface of the projection 3a becomes a mounting surface when a workpiece such as a semiconductor wafer is mounted. The surface roughness of the protrusion 3a and the flat surface 3b that are the base of the resin layer 7 will be described later. Further, the main surface of the dielectric substrate 3 provided with the electrodes 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 opens on the surface of the resin layer 7, 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). A gas supply means (not shown) supplies helium gas or argon gas. And the space 3c provided by forming the plane part 3b becomes a passage of the supplied gas. The spaces 3c communicate with each other, and the supplied gas is distributed throughout.

Further, when a workpiece such as a semiconductor wafer is placed, a ring-shaped protrusion (not shown) can be disposed at a position that supports the outer peripheral portion of the workpiece, so that the aforementioned gas can be prevented from leaking. . When a through hole other than the gas supply through hole 11 is provided, a ring-shaped protrusion (not shown) is provided around the through hole so that the gas does not leak out. You can also The resin layer 7 can be formed on such a ring-shaped protrusion as in the case of the protrusion 3a.
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. The resin layer 7 can also be formed in this gas distribution groove.

  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 of the electrostatic chuck.
In this case, it is more preferable that the volume resistivity be 10 ⁹ Ωcm or more and 10 ¹¹ Ωcm or less in the operating temperature region of the electrostatic chuck. 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 adsorption / desorption responsiveness 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 resin layer 7 is eroded or peeled off, large-sized particles are generated from the dielectric substrate 3. It is because it can suppress degranulation.

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).

  The total thickness of the dielectric substrate 3 and the resin layer 7 is preferably 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 the electrode 4 is securable. In addition, the electrostatic chuck 1 having good heat transfer from the workpiece to the base 2 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 a gold-platinum alloy. be able to.

  Here, the material, volume resistivity, thickness dimension and variation thereof, surface roughness, etc. of the resin layer 7 have a great influence on the corrosion resistance, the occurrence of particle contamination, the adsorption / desorption response, and the like. Therefore, it is important to keep the volume resistivity, thickness dimension, variation thereof, surface roughness, and the like of the resin layer 7 within a predetermined range. Hereinafter, the knowledge obtained by the present inventors regarding the resin layer 7 will be illustrated.

  The material of the resin layer 7 is preferably a resin having corrosion resistance such as a polyimide resin, a polyurea resin, and a fluorine resin. In particular, if it is a polyimide resin, it is excellent in corrosion resistance, heat resistance, and insulation, and it is possible to form a film with excellent coating characteristics on a surface with steps and irregularities by the vapor deposition polymerization method described later. This is more preferable. In this case, at least a polyimide resin may be included.

The volume resistivity at 25 ° C. of the resin layer 7 is preferably 10 ¹⁴ Ωcm or more. If it is less than 10 ¹⁴ Ωcm, a current flows to the object to be processed through the resin layer 7, so that the Johnsen-Rahbek force may increase. As a result, the residual adsorptive power increases, and the adsorption / desorption response may be deteriorated.

  The thickness dimension of the resin layer 7 is preferably 5 μm or more and 15 μm or less. Here, the surface shape of the base is transferred to the surface of the resin layer 7 formed thereon, and the lower the thickness dimension of the resin layer 7, the more easily it is affected. Therefore, if the thickness dimension of the resin layer 7 is less than 5 μm, it will be greatly affected by the base, so it is difficult to reduce the surface roughness in the polishing process (finishing process) after the resin layer 7 is formed. This is because there is a case. On the other hand, if the thickness dimension of the resin layer 7 exceeds 15 μm, the adsorptive power may be too small.

  The variation of the thickness dimension of the resin layer 7 is preferably −10% or more and + 10% or less. This is because if the variation in the thickness dimension of the resin layer 7 is less than −10% or exceeds + 10%, the variation in the adsorption force becomes too large, or the in-plane distribution of the adsorption force becomes too large. The resin layer 7 having a thickness dimension variation of −10% or more and + 10% or less can be formed by, for example, a vapor deposition polymerization method or a CVD (Chemical Vapor Deposition) method.

  It is preferable that the surface roughness of the resin layer 7 formed on the top surface of the protrusion 3a is 0.01 μm or more and 0.1 μm or less in terms of arithmetic average roughness Ra. In order for the surface roughness of the resin layer 7 formed on the top surface of the protrusion 3a to be less than 0.01 μm in terms of arithmetic average roughness Ra, the polishing process (finishing process) after the resin layer 7 is formed This is because a lot of time is required to reduce the productivity. On the other hand, if the surface roughness of the resin layer 7 formed on the top surface of the protruding portion 3a exceeds 0.1 μm in terms of arithmetic average roughness Ra, chip pockets (fine concave portions) are formed in this portion. There is a risk. 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. Alternatively, particles contaminated into the chip pocket may be directly attracted and transferred to the object to be processed, thereby causing particle contamination. The “surface roughness” in this specification is based on “JIS B0601: 2001”.

  Further, the surface roughness of the resin layer 7 formed on the surface of the flat portion 3b is preferably 1 μm or less in terms of arithmetic average roughness Ra. If the surface roughness of the resin layer 7 formed on the surface of the planar portion 3b exceeds 1 μm in terms of arithmetic average roughness Ra, a chip pocket may be formed in this portion. Then, fine particles generated when the resin layer 7 formed on the top surface of the protruding portion 3a is polished may enter the chip pocket, and particle contamination may occur due to the release of the particles later. Because there is.

Next, the protrusion 3a will be further illustrated.
The horizontal cross section of the protrusion 3a can have any shape. However, if the shape has no corners, such as a circle, cracks and chips can be suppressed.

  If the shape of the cross section in the horizontal direction of the protrusion 3a is circular, the diameter dimension is preferably 0.1 mm or more and 1.0 mm or less. This is because if the diameter dimension is less than 0.1 mm, it is difficult to form the protrusion 3a. On the other hand, if the diameter 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 deteriorate adsorption / desorption response. is there.

  It is preferable that the height of the protrusion 3a be 2 μm or more and 15 μm or less. If the height of the protrusion 3a is less than 2 μm, the surface of the object to be processed and the surface of the resin layer 7 formed on the surface of the flat part 3b may come into contact when the object to be processed is adsorbed. Because there is. On the other hand, if the height dimension of the protruding portion 3a exceeds 15 μm, the space coulomb force described later is weakened, so that the attractive force may be insufficient.

  It is preferable that the arrangement pitch dimension of the protrusions 3a be 2 mm or more and 15 mm or less. This is because if the arrangement pitch dimension 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 the adsorption / desorption response. On the other hand, if the arrangement pitch dimension exceeds 15 mm, the surface of the object to be processed and the surface of the resin layer 7 formed on the surface of the flat portion 3b may come into contact when the object to be processed is adsorbed. Because there is.

The contact area ratio between the protrusion 3a and the object to be processed is preferably 0.005% or more and 1.5% or less. This is because if the contact area ratio is less than 0.005%, the forming process of the protrusion 3a may be difficult. Moreover, it is because there exists a possibility that the surface of a to-be-processed object and the surface of the resin layer 7 formed in the surface of the plane part 3b may contact when a to-be-processed object is adsorb | sucked. On the other hand, if the contact area ratio exceeds 1.5%, the total contact area with the object to be processed becomes too large, which may increase particle contamination due to rubbing and deteriorate the adsorption / desorption response. Because.
In this case, 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 resin layer 7 is illustrated.
The surface roughness of the base of the resin layer 7, that is, the surface roughness of the protrusion 3 a and the flat portion 3 b is the surface roughness of the resin layer 7 formed on these and the adhesion between the resin layer 7 and the base. (Peeling resistance) is greatly affected. For this reason, it is important that the surface roughness of the protrusion 3a and the flat portion 3b is within a predetermined range.

ここで、下地と樹脂層７との間の密着力の測定には、引き倒し法を用いた。具体的には、樹脂層７に対して垂直に円筒棒を接着し、円筒棒の所定の位置に樹脂層７に対して平行な方向に力を加え、円筒棒が倒れたときの力を測定した。この場合、加えた力をＦ（Ｎ）、円筒棒の半径寸法をＲ（ｍ）、樹脂層７から力の作用点までの高さ寸法をｈ（ｍ）とすると、密着力ｆ（Ｐａ）は、以下の（１）式で表すことができる。 Hereinafter, the knowledge obtained by the inventors regarding the surface roughness of the base of the resin layer 7 will be illustrated. FIG. 2 is a graph for illustrating the relationship between the surface roughness of the base and the adhesion force. The horizontal axis represents the surface roughness (arithmetic average roughness Ra) of the base, and the vertical axis represents the adhesion between the resin layer 7 and the base. In addition, the base is made of a ceramic sintered body used for forming the dielectric substrate 3 described above, and the resin layer 7 is made of a polyimide resin.
Table 1 is a table showing the relationship between the surface roughness of the base and the adhesion force illustrated in FIG.

Here, the pulling-down method was used for the measurement of the adhesive force between the base and the resin layer 7. Specifically, a cylindrical rod is bonded perpendicularly to the resin layer 7, a force is applied in a direction parallel to the resin layer 7 at a predetermined position of the cylindrical rod, and the force when the cylindrical rod falls is measured. did. In this case, if the applied force is F (N), the radial dimension of the cylindrical rod is R (m), and the height dimension from the resin layer 7 to the point of action of the force is h (m), the adhesion force f (Pa) Can be expressed by the following equation (1).

そして、次のようにして密着力の測定を行った。
円筒棒としては、材料が高炭素クロム軸受け鋼材（ＳＵＪ材）、ロックウェル硬さがＨＲＣ５８以上、半径寸法Ｒが３ｍｍ、長さ寸法が５０ｍｍのものを用いた。また、円筒棒と樹脂層７との接着には、エポキシ接着剤（エポキシレジン ＸＤ９１１、ナガセケムテックス製）を用いた。そして、接着乾燥の後、樹脂層７からの高さ寸法ｈが４０ｍｍの位置において、樹脂層７に対して平行な方向に力Ｆを加えた。

And the adhesive force was measured as follows.
As the cylindrical rod, a high carbon chrome bearing steel (SUJ material), a Rockwell hardness of HRC58 or more, a radius R of 3 mm, and a length of 50 mm were used. An epoxy adhesive (epoxy resin XD911, manufactured by Nagase ChemteX) was used for bonding the cylindrical rod and the resin layer 7. Then, after adhesion drying, force F was applied in a direction parallel to the resin layer 7 at a position where the height dimension h from the resin layer 7 was 40 mm.

  Here, when the anchor effect is taken into account, it seems that the adhesion strength increases as the surface roughness of the base increases. Therefore, conventionally, the surface roughness of the base has been increased as much as possible. For example, as described in paragraph [0066] of Patent Document 1 (Japanese Patent Laid-Open No. 2006-287210), the surface roughness of the base is about 1.1 μm in terms of arithmetic average roughness Ra.

However, as a result of the study by the present inventors, it has been found that if the surface roughness of the base is increased too much, the adhesion is rather reduced. That is, as can be seen from FIG. 2, it was found that if the surface roughness of the base is increased, the adhesion is increased, but if it exceeds a certain value, the adhesion is reduced.
In this case, it is preferable that the adhesion is 40 MPa or more in consideration of the peel resistance. This is because if the adhesion force is 40 MPa or more, the resin layer 7 is less likely to be peeled off even when polishing (finishing) is performed after the resin layer 7 is formed. Therefore, the surface roughness (arithmetic average roughness Ra) of the base is preferably 0.06 μm or more and 0.7 μm or less as can be seen from FIG.
In consideration of durability, it is preferable that the adhesion force be 60 MPa or more. As a result of the study by the present inventors, if the adhesion is 60 MPa or more, the polishing process (finishing process) after forming the resin layer 7 can be stably performed. Therefore, as can be seen from FIG. 2 and Table 1, the surface roughness of the base is more preferably 0.1 μm or more and 0.7 μm or less in terms of arithmetic average roughness Ra.
Further, when the surface roughness of the base is 0.17 μm in arithmetic mean roughness Ra and 0.7 μm or less, an adhesive strength of 80 MPa or more can be obtained. Therefore, the peel resistance and durability can be further improved.
Further, if the surface roughness of the base is 0.32 μm or more and 0.41 μm or less in terms of arithmetic average roughness Ra, a very high adhesion force of 110 MPa or more can be obtained. Therefore, the peel resistance and durability can be greatly improved.

The above is the surface roughness of the base that is preferable from the viewpoint of increasing the adhesion, but the surface shape of the base is transferred to the surface of the resin layer 7 formed thereon. Therefore, it may be preferable to consider that the surface shape of the base is transferred.
As described above, in the case of the resin layer 7 formed on the top surface of the protrusion 3a, the surface roughness should be 0.01 μm or more and 0.1 μm or less in terms of arithmetic average roughness Ra. preferable. Therefore, if the transferred irregularities become too large, the processing time (such as the polishing time for finishing) for obtaining such surface roughness (arithmetic average roughness Ra) becomes long, and the productivity is remarkably reduced. There is a fear.

  Therefore, in consideration of these, it is preferable that the surface roughness of the top surface of the protrusion 3a is 0.06 μm or more and 0.3 μm or less in terms of arithmetic average roughness Ra. If the surface roughness of the top surface of the protrusion 3a is less than 0.06 μm in arithmetic mean roughness Ra, the adhesive force becomes too small as described above, and therefore the resin layer 7 formed on the top surface of the protrusion 3a. This is because there is a possibility of peeling. Further, if the surface roughness of the top surface of the protrusion 3a exceeds 0.3 μm in terms of arithmetic average roughness Ra, the unevenness formed on the surface of the resin layer 7 is increased accordingly. As a result, the time required to obtain a surface having the above-described surface roughness (arithmetic average roughness Ra) (such as polishing time for finishing) becomes long, and the productivity may be significantly reduced. .

  The height of the adhesion strength in the flat surface portion 3b also affects the peel resistance in the protruding portion 3a. That is, if the adhesive force in the flat part 3b is high, it can suppress that the resin layer 7 peels in the projection part 3a. Further, as described above, in the case of the resin layer 7 formed on the flat surface portion 3b, the surface roughness may be set to 1 μm or less in terms of arithmetic average roughness Ra. Therefore, the surface roughness (for example, arithmetic average roughness Ra) of the flat portion 3b may be set to the surface roughness (for example, arithmetic average roughness Ra) that is preferable from the viewpoint of increasing the above-described adhesion.

  Therefore, the surface roughness of the flat portion 3b is an arithmetic average roughness Ra, which is preferably 0.06 μm or more and 0.7 μm or less, more preferably 0.1 μm or more and 0.7 μm or less. Moreover, it is more preferable that the surface roughness of the flat portion 3b is 0.32 μm or more and 0.41 μm or less in terms of arithmetic average roughness Ra. In this case, since the surface roughness of the flat portion 3b is 0.7 μm or less in terms of arithmetic average roughness Ra, the surface roughness Ra of the resin layer 7 is suppressed from exceeding 1 μm by the transfer.

  If the forming process is performed such that the surface roughness of the flat surface portion 3b exceeds 1.0 μm in terms of the arithmetic average roughness Ra, the dimensional accuracy of the protruding portion 3a may be deteriorated. For example, in order to form the flat surface portion 3b using a sandblasting method, which will be described later, and to make the surface roughness exceed 1.0 μm in arithmetic average roughness Ra, an abrasive having a particle size larger than usual is used. There is a need to. For this reason, it is difficult to control the size of the protruding portion 3a, and the height dimensional accuracy may be deteriorated. Therefore, it is preferable that the surface roughness of the flat surface portion 3b is 1.0 μm or less in terms of the arithmetic average roughness Ra even when considering the formation processing of the flat surface portion 3b.

  The above is the surface roughness that is preferable for each of the top surface of the protrusion 3a and the flat surface portion 3b. In this case, it is preferable that the surface roughness (for example, arithmetic average roughness Ra) of the top surface of the protrusion 3a is smaller than the surface roughness (for example, arithmetic average roughness Ra) of the flat surface portion 3b. . In this way, it becomes easy to make the surface of the resin layer 7 formed on the top surface of the protrusion 3a (the portion in contact with the object to be processed) a smooth surface with little particle generation. On the other hand, the adhesion strength (peeling resistance) between the resin layer 7 and the base can be ensured in the flat portion 3b. In this case, the total area of the flat surface portion 3b is much larger than the total area of the top surface of the protrusion 3a. Therefore, since it can be set as the structure where a part with higher adhesive force increases, it can suppress effectively that the resin layer 7 peels.

Next, the operation of the electrostatic chuck 1 according to the present embodiment will be illustrated.
An object to be processed (for example, a semiconductor wafer) is placed on the surface (mounting surface) of the resin layer 7 formed on the top surface of the protrusion 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 flat surface portion 3b, charges having different polarities are generated in the flat surface portion 3b and the object to be processed held thereabove, and the Coulomb force (between these charges) ( The object to be processed is adsorbed and fixed by the space Coulomb force. 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, since the object to be processed and the resin layer 7 are in contact with each other in the portion where the Coulomb force is generated (protrusion portion 3a portion), there is a possibility that particles are generated. However, since the surface roughness of the resin layer 7 is as described above, the generation of particles can be suppressed. In addition, since the thickness dimension of the resin layer 7 falls within the predetermined range described above, the variation in the adsorption force is reduced.

  Further, in the portion where the space Coulomb force is generated (the flat portion 3b portion), the object to be processed and the resin layer 7 do not come into contact with each other, so that no particles are generated due to rubbing. Therefore, the occurrence of particle contamination can be greatly reduced by increasing the number of portions where the space Coulomb force is generated. In the electrostatic chuck 1 according to the present embodiment, the height dimension, the arrangement pitch dimension, the diameter dimension, the contact area ratio between the projection part 3a and the object to be processed, and the like are set as described above. Therefore, it is possible to increase the portion where the space Coulomb force is generated. Moreover, even if it is a case where a to-be-processed object bends, it can suppress that the resin layer 7 formed in the plane part 3b and a to-be-processed object contact. 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).

  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. Note that, as an example, the case where the temperature control is performed using the cooling liquid or the heating liquid is illustrated, but other temperature control means such as a heater may be provided to control the temperature of the object to be processed.

  A gas (for example, helium gas) supplied from a gas supply means (not shown) is introduced into the space 3c through the through hole 11 after the pressure and flow rate are adjusted by a pressure control means and a flow rate control means (not shown). Is done. The introduced gas passes through the space 3c and reaches the entire space 3c communicated with each other. And since the thermal conductivity is remarkably enhanced by the introduced gas, the object to be processed is heated and cooled effectively.

  In addition, when a ring-shaped protrusion (not shown) is disposed at a position that supports the outer peripheral portion of the workpiece when a workpiece such as a semiconductor wafer is placed, the gas described above is Leakage to the outside of 1 is suppressed. Further, when a ring-shaped protrusion (not shown) is disposed around the through-holes other than the above-described through-holes 11, the gas leaks out of the electrostatic chuck 1 through the through-holes. It is suppressed. In addition, when a gas distribution groove (concave groove) (not shown) communicating with the through hole 11 is provided, the gas distribution speed can be increased, so that the temperature of the object to be processed can be quickly controlled. .

ここで、パーティクルの発生数の測定を行った際に用いた測定方法について説明をする。
まず、直径２００ｍｍのシリコンベアウェーハ（モニターグレード）を用意する。そして、静電チャック１への吸着前に、ウェーハ裏面のパーティクル数をパーティクルカウンターで測定する。ここで、パーティクルカウンターには、ＫＬＡ−Ｔｅｎｃｏｒ社製、ＳＦＳ−６２２０を用いた。また、レーザのゲインを４、ヘイズ測定をＯＦＦとし、測定レンジとしては、０．１６μｍ以上、１０μｍ以下を５カラムに分け、１０μｍを超えるものについては、巨大欠陥のカウント数として転記することにした。
また、測定には、外径寸法が３００ｍｍ、双極電極タイプ、突起部の直径寸法が０．５ｍｍ、突起部の配設ピッチ寸法が約５ｍｍ、突起部の高さ寸法が１０μｍ、ポリイミド系樹脂からなる樹脂層７の厚み寸法が１０μｍの静電チャック１を用いた。
シリコンベアウェーハの吸着条件としては、印可電圧を±８００ＶＤＣとし、減圧雰囲気（１０^−２Ｐａ以下）中において３０秒間の静電吸着を行なうものとした。
そして、静電吸着の後、ウェーハ裏面のパーティクル数を再度測定し、吸着前のパーティクル数を差し引いたものをパーティクルの発生数として表２にまとめた。 Next, other measurements performed by the present inventors will be exemplified.
Table 2 is a table for illustrating measurement results of the number of generated particles.

Here, a measurement method used when measuring the number of generated particles will be described.
First, a silicon bare wafer (monitor grade) having a diameter of 200 mm is prepared. Then, before adsorption to the electrostatic chuck 1, the number of particles on the back surface of the wafer is measured with a particle counter. Here, as the particle counter, SFS-6220 manufactured by KLA-Tencor was used. In addition, the laser gain is 4, the haze measurement is OFF, and the measurement range is 0.16 μm or more and 10 μm or less is divided into 5 columns, and those exceeding 10 μm are transferred as the count number of giant defects. .
For measurement, the outer diameter is 300 mm, the bipolar electrode type, the diameter of the protrusion is 0.5 mm, the protrusion pitch is about 5 mm, the height of the protrusion is 10 μm, and the polyimide resin is used. The electrostatic chuck 1 having a resin layer 7 with a thickness of 10 μm was used.
As the adsorption conditions for the silicon bare wafer, the applied voltage was set to ± 800 VDC, and electrostatic adsorption was performed for 30 seconds in a reduced pressure atmosphere (10 ⁻² Pa or less).
Then, after electrostatic adsorption, the number of particles on the back surface of the wafer was measured again, and the number of particles before adsorption was subtracted from the number of particles generated in Table 2.

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を形成するようにすれば、平面部３ｂの表面粗さを前述した範囲内（算術平均粗さＲａで０．０６μｍ以上、０．７μｍ以下）に収めることができる。 As can be seen from Table 2, in the electrostatic chuck 1 according to the present embodiment, the number of particles generated can be significantly reduced. For example, in the electrostatic chuck disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2006-287210), the number of generated particles, which is 1000 to 5000 (see paragraph [0074] in Patent Document 1), is 94. It was possible to greatly reduce the number.
Table 3 is a table for illustrating the surface roughness of the flat portion 3b formed by using the sandblast method.

As can be seen from Table 3, if the flat surface portion 3b is formed using the sand blast method, the surface roughness of the flat surface portion 3b is within the above-described range (the arithmetic average roughness Ra is 0.06 μm or more, 0.7 μm). Below).

  Table 4 shows the surface roughness (arithmetic average roughness Ra) immediately after the formation of the resin layer 7 formed on the top surface of the protrusion 3a (immediately after the formation of the resin layer 7) and the surface roughness after polishing ( It is a table | surface for illustrating arithmetic mean roughness Ra).

表４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樹脂層７表面（被処理物との接触面）の表面粗さ（算術平均粗さ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 4, the surface roughness (arithmetic average roughness Ra) of the surface of the resin layer 7 (contact surface with the object to be processed) formed on the top surface of the protrusion 3a is as described above when the polishing process is performed. Within the range (0.01 μm or more and 0.1 μm or less).

表５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であっても被処理物（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、被処理物の表面と平面部３ｂの上方に形成された樹脂層７の表面との接触を防止することができる。 Table 5 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 5, 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 of the object to be processed (semiconductor wafer) even if the adsorption force is large. (1.55 μm or less) can be made smaller than the height dimension (2 μm or more and 15 μm or less) of the protrusion 3 a described above. Therefore, contact between the surface of the object to be processed and the surface of the resin layer 7 formed above the flat portion 3b can be prevented.

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.
The raw material (granular powder) used for forming the dielectric substrate 3 can be manufactured as follows.
For example, in the production of raw materials (granular powder), first, an alumina raw material powder having an average particle size of 0.1 μm and a purity of 99.99% or more is used as a raw material, which exceeds 0.2 wt% and is 0.6 wt% or less. Of titanium oxide (TiO ₂ ). Next, the mixture is pulverized and an acrylic binder is added. And it granulates with a spray dryer after adjustment, and granule powder is manufactured.

Next, the raw material (granular powder) described above is used for molding by CIP (rubber press) or mechanical press. Thereafter, it is processed into a predetermined shape and fired in a reducing atmosphere of 1150 ° C. to 1350 ° C. Then, the dielectric substrate 3 is formed by subjecting the fired product to HIP processing (hot isostatic pressing). (Step S1)
The conditions of 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. Under such conditions, the relative density is 99% or more, the average particle diameter of the constituent particles is 2 μm or less, the volume resistivity is 10 ⁸ to 10 ¹¹ Ωcm at 20 ± 3 ° C., and the thermal conductivity is 30 W / mK. The above dielectric substrate 3 is obtained.

In addition, the average particle diameter here is a particle diameter obtained by the following planimetric method.
When obtaining the particle diameter by the planimetric method, first, a picture of the dielectric substrate 3 is taken with a scanning electron microscope (SEM). Next, a circle with a known area S is drawn on this photograph. Then, the number of particles nc in the circle and the number of particles ni applied to the circumference are calculated, and the number of particles NG per unit area is obtained by the following equation (2).

ここで、ｍは写真の倍率である。

Here, m is the magnification of the photograph.

  Since 1 / NG is the area occupied by one particle, the average particle diameter can be determined by the following equation (3) as the equivalent circle diameter.

次に、誘電体基板３の一方の主面を研削加工する。そして、研削加工がされた面に前述のチタンまたはチタン化合物などからなる導電膜を形成する。導電膜の形成には、ＣＶＤ（Chemical Vapor Deposition）法やＰＶＤ（Physical Vapor Deposition）法などを用いることができる。この形成された導電膜を所定の形状に加工することで、所望の形状の電極４を形成する。導電膜の加工には、サンドブラスト法やエッチング法などを用いることができる。（ステップＳ２）
なお、電極４には電線９が適宜配線される。

Next, one main surface of the dielectric substrate 3 is ground. Then, a conductive film made of the aforementioned titanium or titanium compound is formed on the ground surface. For the formation of the conductive film, a CVD (Chemical Vapor Deposition) method, a PVD (Physical Vapor Deposition) method, or the like can be used. By processing the formed conductive film into a predetermined shape, the electrode 4 having a desired shape is formed. For the processing of the conductive film, a sandblasting method, an etching method, or the like can be used. (Step S2)
An electric wire 9 is appropriately wired to the electrode 4.

Next, the projecting portion 3a and the flat portion 3b are formed on the main surface (the surface facing the surface on which the electrode 4 is formed) on the dielectric substrate 3 on which the object to be processed is placed by using the sandblast method. To do. (Step S3)
In addition, the projection part 3a is formed by forming the plane part 3b as described later.

In the formation of the protrusion 3a and the flat portion 3b, first, the principal surface of the dielectric substrate 3 on the side on which the object to be processed is placed is polished, and the surface roughness is 0.06 μm in terms of arithmetic average roughness Ra. As mentioned above, it is 0.3 micrometer or less. Thereafter, a resist film is attached to the surface, exposed and removed to form a mask having a desired shape. (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. Since the portion covered with the mask is the top surface of the protrusion 3a, the surface roughness of the top surface of the protrusion 3a is within the above-described range (the arithmetic average roughness Ra is 0.06 μm or more and 0.3 μm or less). .

Next, the part which is not covered with the mask among the main surfaces used as the side which mounts the to-be-processed object of the dielectric substrate 3 is removed using the sandblasting method. (Step S3b)
In this case, the removed portion becomes the flat surface portion 3b.
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. For this reason, variations in dimensions from the surface of the planar portion 3b to the object to be processed can be suppressed, and variations in the electrostatic force (space Coulomb force) to be expressed can be suppressed.
In addition, by performing the formation of the flat surface portion 3b by the sand blast method, as shown in Table 3, the surface roughness is within the above-described range (the arithmetic average roughness Ra is 0.06 μm or more and 0.7 μm or less). Can be.
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 layer 7 is formed so as to cover the protruding portion 3a and the flat portion 3b. (Step S4) The material of the resin layer 7 can be a polyimide resin, for example. In addition, it can also contain a polyimide resin at least. Moreover, the thickness dimension of the resin layer 7 shall be 5 micrometers or more and 15 micrometers or less. In this case, the resin layer 7 can be formed by various film forming methods such as vapor deposition polymerization, CVD (Chemical Vapor Deposition), and spin coating. In this case, it is preferable to use a vapor deposition polymerization method or a CVD (Chemical Vapor Deposition) method in order to set the variation of the thickness dimension of the resin layer 7 to −10% or more and + 10% or less.

Next, it finishes so that the surface (contact surface with a to-be-processed object) of the resin layer 7 formed in the top face of the projection part 3a may become smooth. (Step S5)
At this time, the surface roughness of the resin layer 7 formed on the top surface of the protrusion 3a is set within the above-described range (the arithmetic average roughness Ra is 0.01 μm or more and 0.1 μm or less). For example, such a surface roughness can be obtained by polishing.

On the other hand, the base 2 having 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 S6)
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 of the base 2 on which the insulator layer 5 is provided are joined using an insulating adhesive. (Step S7)
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 resin layer 7 is cleaned as necessary. (Step S8)
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 1a according to another embodiment. 4A is a schematic cross-sectional view for illustrating an electrostatic chuck, and FIG. 4B is a schematic enlarged view of a portion B in FIG. 4A.
FIG. 5 is a flowchart for illustrating a method of manufacturing the electrostatic chuck 1a illustrated in FIG.
The electrostatic chuck 1a is the same as the electrostatic chuck 1 illustrated in FIG. 1 except that the base 2 is not provided, and thus the description of the configuration is omitted.

  This is different from the method for manufacturing the electrostatic chuck illustrated in FIG. 3 in the procedure for forming the protrusion 3a and the flat surface 3b. That is, after the insulating layer 5 and the dielectric substrate 3 are joined, the protrusion 3a and the flat portion 3b are formed on the surface of the dielectric substrate 3 (the main surface on which the object to be processed is placed) by sandblasting. I am doing so.

That is, first, as in step S1 of FIG. 3, the dielectric substrate 3 is formed from raw materials through molding, firing, and HIP processing. (Step S11)
Next, an electrode is formed on one main surface of the dielectric substrate 3 in the same manner as in step S2 of FIG. (Step S12)
On the other hand, the insulator layer 5 is formed. (Step S13)
Then, similarly to step S7 in 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, as in 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 as in step S3c of FIG. (Step S15c)
Next, in the same manner as in step S4 of FIG. 3, the resin layer 7 is formed so as to cover the protruding portion 3a and the flat portion 3b. (Step S16)
Next, as in step S5 of FIG. 3, the surface of the resin layer 7 formed on the top surface of the protrusion 3a (contact surface with the object to be processed) is finished to be smooth. (Step S17)
Next, as in step S8 of FIG. 3, the surface of the resin layer 7 is cleaned as necessary. (Step S18)
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, 4 electrode, 5 insulator layer, 6 bonding layer, 7 resin layer, 8 flow path, 9 Electric wire, 10a power supply, 10b power supply, 11 Through hole

Claims (9)

A protrusion formed on the main surface on the side for placing an object to be processed, have a, and a flat portion formed in the periphery of the protrusions, a dielectric substrate ing ceramic sintered body,
A resin layer formed so as to cover the protrusion and the flat portion;
An electrostatic chuck comprising:
The volume resistivity at 25 ° C. of the resin layer is 10 ¹⁴ Ωcm or more,
The surface roughness of the top surface of the protrusion that is the base of the resin layer is smaller than the surface roughness of the planar portion
The surface roughness of the top surface of the protrusion, which is the base of the resin layer, is 0.06 μm or more and 0.3 μm or less in terms of arithmetic average roughness Ra,
The electrostatic chuck characterized in that the surface roughness of the flat portion, which is the base of the resin layer, is 0.06 μm or more and 0.7 μm or less in terms of arithmetic average roughness Ra .   2. The electrostatic chuck according to claim 1, wherein the surface roughness of the resin layer formed on the top surface of the protrusion is 0.01 μm or more and 0.1 μm or less in arithmetic mean roughness Ra. . 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 electrostatic chuck according to the resin layer, any one of claims 1-3, characterized in that it comprises a polyimide resin. The resin layer, the electrostatic chuck according to any one of claims 1-4, characterized in that, formed by a vapor deposition polymerization method. Contact area ratio of the projections and the object to be processed, 0.005% or more, the electrostatic chuck according to 1.5% or less, any one claims 1 to 5, characterized in. Polishing the main surface of the dielectric substrate made of a ceramic sintered body on the side on which the workpiece is placed, providing a mask of a desired shape on the main surface,
By forming a flat portion by removing a portion that is not covered by the mask using a sandblast method, a protrusion is formed,
A resin layer is formed by coating the resin so as to cover the protrusion and the flat portion,
A method of manufacturing an electrostatic chuck for polishing the surface of the resin layer formed on the top surface of the protrusion,
When forming the flat portion and the protrusion, the surface roughness of the top surface of the protrusion is made smaller than the surface roughness of the flat portion ,
When polishing the main surface, the surface roughness of the main surface is such that the arithmetic average roughness Ra is 0.06 μm or more and 0.3 μm or less, so that the top surface of the protrusion is formed. The surface roughness is such that the arithmetic average roughness Ra is 0.06 μm or more and 0.3 μm or less,
When forming the flat portion, the surface roughness of the flat portion is set to an arithmetic average roughness Ra of more than 0.06 μm and 0.7 μm or less. . When performing the polishing process, the surface roughness of the surface of the resin layer formed on the top surface of the protrusion is set to an arithmetic average roughness Ra of 0.01 μm or more and 0.1 μm or less. The method of manufacturing an electrostatic chuck according to claim 7 . The method for manufacturing an electrostatic chuck according to claim 7 , wherein the resin layer is formed using a vapor deposition polymerization method.

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