JPWO2013051713A1 - Sample holder - Google Patents

Abstract

Provided is a sample holder that can suppress the occurrence of cracks in a substrate when a fluid is passed through a flow path inside the substrate. An electrostatic chuck (1), which is a sample holder according to an embodiment of the present invention, includes a plurality of ceramic layers laminated, and a flow path (11) having a rectangular cross-sectional shape perpendicular to the longitudinal direction. It has a base (10) provided and a coating film (30) that covers the inner surface of the corner (10a) in a cross-sectional shape perpendicular to the longitudinal direction of the flow path (11).

Description

  The present invention relates to a process such as polishing, inspection, and conveyance for each sample such as a silicon wafer or a glass substrate used in each manufacturing process in a manufacturing process of a semiconductor integrated circuit and a manufacturing process of a liquid crystal display device. The present invention relates to a sample holder that holds each sample when performing the above.

  A semiconductor wafer made of silicon or the like used for manufacturing a semiconductor integrated circuit and a plate-like sample such as a glass substrate used for manufacturing a liquid crystal display device are held on a support table of a manufacturing apparatus or an inspection apparatus in the manufacturing process. Then, processing and inspection are performed. In a manufacturing process, it is common to use a plurality of manufacturing apparatuses and inspection apparatuses, and means for holding a sample such as a silicon wafer on a support base are the types of manufacturing apparatuses and inspection apparatuses in the manufacturing process, Various types of devices have been proposed according to the type of the conveying device for conveying to the first device.

  Taking a semiconductor integrated circuit as an example, demands for miniaturization and higher density of the semiconductor integrated circuit and shortening of the manufacturing time of the integrated circuit have been further increased in recent years. Accompanying such a demand, as performance required for the sample holder, for example, when heat treatment is performed on the wafer, temperature uniformity of the sample and suppression of temperature change are required when energy is injected by exposure.

  Japanese Patent Laid-Open No. 3-108737 discloses an electrostatic chuck composed of a plurality of ceramic layers, and this electrostatic chuck has a refrigerant flow path formed in an intermediate ceramic layer. Thereby, the wafer can be directly cooled by the electrostatic chuck.

  In the case where the ceramic layer is formed of a substrate like the electrostatic chuck described in Japanese Patent Laid-Open No. 3-108737, the cross-sectional shape of the flow channel provided inside the substrate is a rectangular shape. When a fluid is caused to flow, the pressure due to the fluid is concentrated at the corner of the flow path. For this reason, cracks may occur at the corners of the substrate facing the flow path, and fluid leakage may occur.

  The present invention provides a sample holder that can suppress the occurrence of cracks in a substrate when a fluid is passed through a flow path inside the substrate.

  A sample holder according to an embodiment of the present invention includes a substrate in which a plurality of ceramic layers are laminated, a channel having a rectangular cross-sectional shape perpendicular to the longitudinal direction is provided inside, and a length of the channel. And a coating film covering the inner surface of the corner in the cross-sectional shape perpendicular to the direction.

  According to the sample holder of this embodiment, it is possible to suppress the occurrence of cracks at the corners of the base body in which the flow path is formed when a fluid is passed through the flow path provided inside the base body.

Objects, features, and advantages of the present invention will become more apparent from the following detailed description and drawings.
It is a perspective view which shows the external appearance of the electrostatic chuck 1 which is embodiment of this invention. It is a top view which shows the external appearance of the electrostatic chuck 1 which is embodiment of this invention. FIG. 3 is a schematic diagram illustrating a planar arrangement position of a flow path 11 inside a base body 10. It is sectional drawing of the electrostatic chuck 1 in cut surface line AA 'shown in FIG. FIG. 4 is a partially enlarged sectional view in which one channel section in the sectional view shown in FIG. 3 is enlarged. It is the elements on larger scale which expanded one channel section of electrostatic chuck 1A which is other embodiments of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1A is a perspective view showing an appearance of an electrostatic chuck 1 according to an embodiment of the present invention. FIG. 1B is a plan view showing an appearance of the electrostatic chuck 1 according to the embodiment of the present invention.

  The electrostatic chuck 1 includes a base 10, an electrode layer 20, and a coating film 30. The electrostatic chuck 1 is a sample holder that holds a sample such as a silicon wafer on the main surface of the substrate 10 by an electrostatic force by applying a voltage to the electrode layer 20 formed on the substrate 10.

  In the present embodiment, the base body 10 is formed of a laminated body in which a plurality of ceramic layers are laminated, and a flow path 11 for flowing a fluid is provided inside the laminated body. The electrostatic chuck 1 can heat, cool, or keep the held sample by flowing a fluid through the flow path 11. Any fluid can be used as the fluid flowing in the flow path 11 as long as it is a heat medium that can exchange heat with the held sample through the ceramic layer and the electrode layer 20 from the flow path 11 to the one main surface of the substrate 10. May be. For example, an aqueous medium such as hot water, cold water, and steam, a brine such as 50% ethylene glycol, and a gas containing air can be used as the fluid.

  As shown in FIG. 1A, the flow path 11 has an opening 11a that communicates with the external space on the end surface of the base 10, and although not shown, an opening that communicates with the external space also on the end surface opposite to the opening 11a. have. For example, the fluid flowing in the flow path 11 flows into the flow path 11 from the opening 11a serving as the supply port, and is discharged from the opening on the opposite side of the opening 11a. When the electrostatic chuck 1 is used in a manufacturing apparatus, an inspection apparatus, or the like, a supply pipe extending from a supply apparatus for supplying a fluid as a heat medium is connected to the opening 11a, and a flow path is supplied from the supply apparatus at a predetermined flow rate and flow rate. 11 is supplied with fluid. A drain pipe is connected to the outlet on the opposite side of the opening 11a, and the fluid that has flowed through the flow path 11 and exchanged heat with the sample is discharged from the flow path 11. Alternatively, a return pipe may be connected to the discharge port so that the fluid that has flowed through the flow path 11 and exchanged heat with the sample is discharged from the flow path 11 and returned to the supply device to circulate the fluid.

FIG. 2 is a schematic diagram illustrating the arrangement position of the flow path 11 inside the base 10 in a plan view.
In order for the fluid flowing through the flow channel 11 to efficiently exchange heat with the held sample, it is effective to increase the heat transfer area. If the opening 11a serving as the supply port is linearly connected to the opening 11b serving as the discharge port, the heat transfer area becomes narrow. Therefore, as shown in FIG. 2, the flow path from the opening 11a to the opening 11b is formed. A meandering shape is preferred. Since the heat transfer area is substantially equal to the projected area of the flow path 11 when the substrate 10 is viewed in plan from the thickness direction, the curvature of the curved portion when the width of the flow path 11 is increased or the flow path 11 is meandered. By reducing the radius, the heat transfer area can be increased. Note that if the distance between the straight line portions when meandering is made too short, the portion that becomes the side wall of the flow path 11 becomes thin and the mechanical strength decreases. It is preferable to arrange the flow path 11 so that the heat area is widened.

  In the example illustrated in FIG. 2, the flow path 11 has a meandering shape, but is not limited thereto, and may have a spiral shape, or may be a combination of a plurality of concentric circles and a straight line extending in the radial direction connecting the circles. .

  In such a channel 11, the channel cross section is formed in a rectangular shape by the inner surface of the base 10, and the base 10 is a flat connecting four corners corresponding to the corners of the channel 11 and adjacent corners. Part. Thus, the inner surface of the base 10 constituting the channel 11 having a rectangular channel cross section is composed of four inner surfaces sequentially connected so as to form an annular shape. In addition, the corner is an inner corner of a portion of the flow path 11 where the two inner surfaces are connected.

  Base 10 is made of, for example, a ceramic sintered body or glass mainly composed of silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, or the like. Among these, an aluminum nitride sintered body or a silicon carbide sintered body is preferable. Since the aluminum nitride sintered body and the silicon carbide sintered body have a thermal conductivity at room temperature of 180 W / (m · K) or more, which is higher than that of other materials, locally heat is applied to the held sample. Even when is added, the heat of the sample can be conducted and dissipated, and the sample is hardly distorted due to thermal expansion. Thereby, in the exposure process in the semiconductor manufacturing process, it is possible to reduce the deterioration of the exposure accuracy due to the distortion of the sample due to heat generation. The thermal conductivity at room temperature is a value measured with the measured atmospheric temperature within the range of 22 ° C. to 24 ° C., and the thermal conductivity measured at any set temperature within this temperature range is 180 W / ( m · K) or more. Furthermore, even in an environment exceeding room temperature, the thermal conductivity can be maintained at a high value, and for example, the thermal conductivity of 60 W / (m · K) or higher can be maintained even at an ambient temperature of 600 ° C. or higher.

  The aluminum nitride sintered body and the silicon carbide sintered body preferably have an average crystal grain size in the range of 3 to 10 μm. When the average particle size is 3 μm or more, the crystal particles in the aluminum nitride sintered body are filled relatively well, and the mechanical properties of the sintered body are made relatively good. In addition, by setting the crystal having an average crystal grain size of 10 μm or less, it is possible to relatively reduce the residual voids existing between the crystals, for example, to favorably suppress the residual particles to the voids. Accordingly, the average crystal grain size is preferably in the range of 3 to 10 μm, more preferably in the range of 3 to 7 μm.

  Returning to FIGS. 1A and 1B, the electrode layer 20 is provided inside the substrate 10 and is composed of two separated electrodes 21 and 22. One of the electrodes 21 and 22 is connected to the positive electrode of the power supply, and the other is connected to the negative electrode. As an example, the electrode connected to the positive electrode is referred to as electrode 21 (hereinafter referred to as “positive electrode 21”), and the electrode connected to the negative electrode is referred to as electrode 22 (hereinafter referred to as “negative electrode 22”). To do. As the electrode layer 20, the electrode 21 may be connected to the negative electrode, and the electrode 22 may be connected to the positive electrode.

  The positive electrode 21 and the negative electrode 22 are each formed in a substantially semicircular shape, and are arranged inside the base body 10 so that the semicircular strings face each other. The two electrodes of the positive electrode 21 and the negative electrode 22 are combined to form a substantially circular outer shape of the entire electrode layer 20. The circular shape that is the outer shape of the electrode layer 20 and the circular shape that is the outer shape of the substrate 10 are concentric circles, and the circular diameter of the outer shape of the electrode layer 20 is smaller than the circular diameter of the outer shape of the substrate 10.

  If the sample to be held by the electrostatic chuck 1 is, for example, a silicon wafer, the outer shape of the silicon wafer is circular. Therefore, it is preferable that the outer shape of the electrode layer 20 be substantially circular according to the outer shape of the sample.

  The positive electrode 21 and the negative electrode 22 are each provided with a connection terminal for electrical connection with an external power source. In the present embodiment, each of the positive electrode 21 and the negative electrode 22 is provided with a connection terminal at a portion where the arc and the string intersect to extend along the string. The connection terminal 21a of the positive electrode 21 and the connection terminal 22a of the negative electrode 22 are provided so as to be adjacent to each other with the same distance as the distance between the strings of the positive electrode 21 and the negative electrode 22, and along the string 10 It extends to the end face of. The connection terminal 21a and the connection terminal 22a are provided so that a part thereof is exposed on the end surface of the base body 10. The positive electrode 21 and the negative electrode 22 are connected to an external power source through this exposed portion.

  The electrode layer 20 is made of a conductive material such as tungsten or molybdenum, for example, and is formed so as to be layered between the ceramic layers of the substrate 10 by, for example, paste screen printing. The thickness of the electrode layer 20 of this embodiment is about 1-5 micrometers, for example.

  The coating film 30 is provided in the flow channel 11 and covers the inner surface of the corner 10 a corresponding to the corner of the flow channel 11.

  3 is a cross-sectional view of the electrostatic chuck 1 taken along a cutting plane line AA ′ shown in FIG. FIG. 4 is a partial enlarged cross-sectional view in which one flow path cross-section in the cross-sectional view shown in FIG. 3 is enlarged. The base 10 is made of a laminate in which four ceramic layers 12, 13, 14, and 15 are laminated, and an electrode layer 20 is disposed therein. In the present embodiment, the electrode layer 20 is provided on the one main surface side that holds the sample with respect to the flow path 11.

  In the following, the outermost ceramic layer 15 is the outermost layer 15, the ceramic layer 12 is provided with the electrode layer 20 between the outermost layer 15, and the upper layer 12 is the ceramic provided on the opposite side of the ceramic layer 13. The layer 14 is referred to as a lower layer 14, and the ceramic layer 13 sandwiched between the upper layer 12 and the lower layer 14 is referred to as an intermediate layer 13. The names of these layers are given for the sake of convenience of explanation, and the upper layer 12 is not necessarily positioned on the upper side in the vertical direction, and the lower layer 14 is not positioned on the lower side in the vertical direction.

  As shown in FIG. 2, the fluid flows from the opening 11a serving as the supply port to the opening 11b serving as the discharge port. Therefore, in FIGS. 3 and 4, the flow direction of the fluid is a direction perpendicular to the paper surface. Therefore, the flow path cross section of the flow path 11 is a cross section in a plane parallel to the paper surface, and is formed in a rectangular shape. Although the flow path 11 in this embodiment is provided in a meandering shape, the cross-sectional shape of the flow path is uniform in the fluid flow direction, and the cross-sectional area of the flow path is also constant.

  In the channel having such a shape, there are four corners, and in this embodiment, the coating film 30 is preferably provided so as to cover all the inner surfaces of the four corners 10a. More specifically, the coating film 30 is bonded to the inner surface of the corner portion 10a constituting the corner on the four inner surfaces of the base body 10 constituting the flow path 11, and covers the inner surface of this portion. Provided.

  Here, in order to describe the four inner surfaces constituting the flow path 11, a method for manufacturing the substrate 10 will be briefly described.

  The substrate 10 of the present embodiment is a laminate in which the four layers of the outermost layer 15, the upper layer 12, the intermediate layer 13, and the lower layer 14 are laminated as described above. The base 10 is formed by applying and laminating four green sheets previously formed into a predetermined shape by applying a metal paste serving as the electrode layer 20 between the green sheet serving as the outermost layer 15 and the green sheet serving as the upper layer 12. It is obtained by firing. The green sheets that become the outermost layer 15, the upper layer 12, and the lower layer 14 after firing have the same disc shape, and the green sheets that become the intermediate layer 13 after firing become green whose outer shapes become the outermost layer 15, the upper layer 12, and the lower layer 14. Although it has the same circular shape as the sheet, a cutout is provided along the shape of the flow path 11.

  When these four green sheets are laminated, the surface facing the notch provided in the green sheet serving as the intermediate layer 13 among the surface of the green sheet serving as the upper layer 12 in contact with the intermediate layer 13 becomes the lower layer 14. Of the surface of the green sheet that is in contact with the intermediate layer 13, a surface facing the notch provided in the green sheet serving as the intermediate layer 13 and two end surfaces facing the notch of the green sheet serving as the intermediate layer 13, It becomes four inner surfaces constituting the flow path 11 after firing. That is, the four inner surfaces constituting the flow path 11 are inner surfaces 131 and 132 that are two end surfaces of the inner surface 121 on the upper layer 12 side, the inner surface 141 on the lower layer 14 side, and the intermediate layer 13.

  The inner surface of the corner portion 10a corresponding to the corner of the flow path 11 is, for example, a first inner surface 121a having a certain width on the inner surface 121 side, the inner surface 121 and the inner surface 131 being connected to each other at an intersecting line perpendicular to each other. The second inner surface 131a having a constant width on the inner surface 131 side.

  Here, the fixed width is not particularly limited as long as it is a width that can suppress the occurrence of cracks in the substrate 10, which is an effect of the present invention. As an example, it can be represented by a ratio with respect to the length of the side in the rectangle of the channel cross section. What is necessary is just to make the width dimension of one inner surface of the inner surface of the corner part 10a into 5 to 50% with respect to the length of the side in a rectangle. Specifically, the length of the side included in the upper layer 12 among the sides in the rectangle is the width dimension of the inner surface 121 in the flow direction, and is 5 mm in the present embodiment. On the other hand, the width of the first inner surface 121a is 1 mm. Moreover, the length of the side contained in the intermediate | middle layer 13 among the sides in a rectangle is the thickness dimension of the intermediate | middle layer 13, and is 3 mm in this embodiment. On the other hand, the width of the second inner surface 131a is 0.6 mm.

  The coating film 30 is provided so as to cover these two inner surfaces, and a portion covering one inner surface and a portion covering the other inner surface are connected and provided integrally. In the case where the coating film 30 is not provided, when a fluid such as water flows in the flow path 11, an outward force is applied to each of the two inner surfaces of the corner 10 a by the flowing fluid. Tensile stress concentrates on the connection location of the two inner surfaces, causing peeling between the upper layer 12 and the intermediate layer 13 or cracking. By providing the coating film 30, the force from the fluid is not directly applied to the two inner surfaces of the corner 10a. Further, there is a portion where the coating film 30 is not provided on the inner surface constituting the flow path 11, and a force from the fluid is applied to this portion, but it is transmitted to the connection location by the coating film 30. Since the force is attenuated, the concentration of stress at the connection point can be greatly reduced.

  Thereby, when a fluid is made to flow through the flow path 11 provided inside the base body 10, it is possible to suppress the occurrence of cracks in the corner portion 10 a of the base body 10.

  The shape of the coating film 30 is not particularly limited as long as it covers the two inner surfaces of the corner 10a. For example, as shown in FIG. 4, the channel cross section may have an L-shaped cross section along the corner. In addition, in the cross-section of the flow path, a triangular prism having a right-angled triangular cross section in which the portions joined to the two inner surfaces of the corner 10a have two sides sandwiching a right angle may be used. In particular, from the viewpoint of stress relaxation, it is desirable that the surface on the opposite side to the side to be joined to the two inner surfaces of the corner portion 10a is a concave curved surface.

  The material of the coating film 30 is not particularly limited as long as a sufficient bonding force with the substrate 10 can be obtained. For example, a ceramic material similar to that of the base 10 may be used, or a metal material may be used, but a metal material is desirable from the viewpoint of strength. If it is a metal material, it should be a refractory metal having a melting point higher than the sintering temperature of the ceramic material, such as tungsten and molybdenum, so that it can be fired simultaneously with the substrate 10 from the viewpoint of the manufacturing method. More preferably, the material is the same as that of the electrode layer 20.

  When a ceramic material is used as the coating film 30, a slurry is prepared by mixing an organic binder, ceramic particles, additives, and the like in the same manner as the green sheet. This slurry is partially applied by printing or the like to a portion where the coating film 30 is to be provided, for example, before the step of laminating the green sheets or during the laminating step. The coating film 30 made of a ceramic material may be formed in the flow path 11 by firing.

  When a metal material is used as the coating film 30, a metal paste in which an organic binder and metal powder are mixed is prepared in advance. For example, a metal paste is partially applied by printing or the like to a portion where the coating film 30 is to be provided before the step of laminating the green sheets or during the step of laminating, and the green sheet and the metal paste And the coating film 30 made of a metal material may be formed in the flow path 11. By forming the coating film 30 using the metal paste in this way, the coating film 30 is thickened to increase the strength and improve the conduction when the ground potential is set as described later. it can.

  When a metal material is used as the coating film 30, a metal film may be formed in the flow path 11 by plating in the base 10 after baking, in addition to baking the metal paste simultaneously with the green sheet. Since the inner surface of the flow path 11 is the surface of the ceramic material, first, a metal thin film is formed by electroless plating, and an electric current is passed through the formed thin film to perform electrolytic plating. When it is desired to provide the coating film 30 only on the corner portion 10a, by selectively depositing a catalyst metal such as palladium on the portion where the coating film 30 is to be provided in advance and performing electroless plating, the corner portion 10a is selectively coated. A thin film can be formed by electroless plating. When the coating film 30 is provided by plating, it is not necessary to consider the sintering temperature of the ceramic material, and a metal material such as copper, silver, gold, nickel, aluminum, or chromium can be used.

  When a metal material is used as the coating film 30, it is provided so that a part of the coating film 30 is exposed to the outside from the opening 11a of the flow path 11 and the like, and exposed to a member that becomes an external ground potential. The coating film 30 may be electrically connected.

  Next, another embodiment of the present invention will be described. In the present embodiment, the coating film 30 </ b> A is provided so as to further cover a portion other than the inner surface of the corner portion 10 a on the inner surface constituting the flow path 11. That is, in addition to the four corners 10a in the flow path 11, the four flat portions 10b are also provided with the coating film 30A so as to further cover the inner surfaces thereof.

  FIG. 5 is a partial enlarged cross-sectional view in which one flow path cross section of an electrostatic chuck 1A according to another embodiment of the present invention is enlarged. The electrostatic chuck 1A of the present embodiment differs from the electrostatic chuck 1 of the above-described embodiment shown in FIGS. 1 to 4 only in the configuration of the coating film 30A. The arrangement of the flow path 11 corresponding to FIG. 2 and the entire cross-sectional view corresponding to FIG. 3 are omitted, and the flow path 11 corresponding to FIG. The present embodiment will be described using an enlarged cross-sectional view.

  In the example shown in FIG. 5, it is provided so that all four inner surfaces which comprise the flow path 11 may be coat | covered, and the more preferable form is shown.

  Electrostatic chucks are broadly classified into two adsorption systems, a Coulomb force type and a Johnson-Labeck force type, depending on the difference in the adsorption system. The Coulomb force type electrostatic chuck uses an insulating material as the base 10 and uses a Coulomb force (electrostatic adsorption force) generated by an electric charge induced between the electrode layer 20 and the object to be processed. Adsorb and hold. On the other hand, the Johnson-Labeck force type electrostatic chuck imparts a slight electrical conductivity to the substrate 10 and holds the object to be processed by suction using the Johnson-Labeck force generated by the charge transfer in the substrate 10.

  In particular, in the case of a Johnson-Rabeck force type electrostatic chuck, when the material of the substrate 10 is a non-oxide ceramic material such as aluminum nitride and silicon carbide, and the fluid flowing in the flow channel 11 is water, the flow channel is A voltage is applied to the flowing water, causing water ionization. Oxygen ions generated by ionization move to the positively charged inner surface of the inner surface constituting the flow channel 11 to cause oxidation on the inner surface, so-called anodic oxidation, and the peripheral portion of the substrate 10 around the flow channel 11 The electrical characteristics of the other parts will be different. Such a partial difference in electrical characteristics causes a variation in characteristics of the substrate 10, which is not preferable.

  Therefore, in this embodiment, by providing the coating film 30A so as to cover all four inner surfaces constituting the flow path 11, even when water is used as the fluid, the occurrence of anodization is suppressed. be able to. More preferably, the coating film 30A is made of a metal material, and the coating film 30A is set to the ground potential.

  The coating film 30 </ b> A of the present embodiment includes a first coating film 31 that covers the entire end face facing the flow path 11 of the intermediate layer 13, an intermediate layer 13 between the upper layer 12 and the intermediate layer 13, and the lower layer 14. The second coating film 32 is provided over the entire area, that is, the entire main surface of the upper layer 12 on the intermediate layer 13 side and the entire main surface of the lower layer 14 on the intermediate layer 13 side. The second coating film 32 does not have to be provided on the entire main surface of the upper layer 12 on the intermediate layer 13 side and on the entire main surface of the lower layer 14 on the intermediate layer 13 side, and faces the flow paths 11 of the upper layer 12 and the lower layer 14. You may provide so that only an inner surface may be coat | covered.

  As a result, the second coating film 32 is exposed on the outer peripheral end surface of the substrate 10, and the exposed member of the ground potential is electrically connected to the exposed second coating film 32. In the coating film 30A, the first coating film 31 and the second coating film 32 are joined at the corner of the flow path 11, and the first coating film 30A is set to the ground potential by setting the second coating film 32 to the ground potential. The coating film 31 also has a ground potential.

  Further, in the present embodiment, the intermediate layer 13 includes a plurality of layers, and in the example illustrated in FIG. 5, the intermediate layer 13 includes two layers of a first intermediate layer 13a and a second intermediate layer 13b. When the intermediate layer 13 is composed of a plurality of layers, each layer has the same shape and is laminated in the thickness direction to form the intermediate layer 13. In such a configuration, the end surface of the intermediate layer 13 facing the flow path 11 is formed by connecting end surfaces of a plurality of layers in the thickness direction.

  As in the above embodiment, when only the inner surface of the corner 10a is covered and the other inner surface where the flow path 11 is desired is exposed, when the intermediate layer 13 is composed of a plurality of layers, the fluid flows into the flow path 11. , The end face of the intermediate layer 13 may be peeled off or cracked at the interface where a plurality of layers are joined. In the present embodiment, by covering the entire end face of the intermediate layer 13 with the first coating film 31, no force from the fluid is directly applied to the end face of the intermediate layer 13 facing the flow path 11. Occurrence of peeling or cracking at the interface to be bonded or the interface between the first intermediate layer 13a and the second intermediate layer 13b can be suppressed.

  Below, an example of the manufacturing method of 1 A of electrostatic chucks shown in FIG. 5 is demonstrated.

  As a starting material, an aluminum nitride powder having an average particle diameter of 1.5 μm, an oxygen content of 0.8%, and a carbon content of 300 ppm manufactured by an alumina reduction nitriding method was used. Then, without adding a sintering aid to the aluminum nitride powder, an organic binder and a solvent were mixed and mixed, and then dried at 60 ° C. to produce granulated powder.

  Next, this granulated powder was filled in a mold, and one disk-shaped molded body having a thickness of 1 mm and three disk-shaped molded bodies having a thickness of 3 mm were molded at a molding pressure of 98 MPa. Thereafter, a notch was formed by cutting on a single molded body having a thickness of 3 mm to be the intermediate layer 13. A metal paste in which an organic binder and tungsten powder were mixed was applied to each of two main surfaces having a thickness of 3 mm in the molded body not cut by a screen printing method to a thickness of 10 μm. Next, the molded body in which the notch was formed was arranged on the surface to which this metal paste was applied. The same metal paste was applied to the side surface of the finished groove. Furthermore, the molded body on which another metal paste was applied was arranged so that the surface on which the paste was applied was in contact with the molded body on which grooves were formed. The finished laminate was press-molded with a molding pressure of 98 MPa and adhered. Further, the electrode layer 20 is formed by screen-printing the tungsten powder paste on the one main surface of the formed compact. On top of that, a 1 mm-thick disk molded body was placed, and press-molded with a molding pressure of 98 MPa to be adhered. Next, degreasing is performed in a nitrogen atmosphere, followed by firing at 1900 ° C. for 2 hours to produce a disk-shaped sintered body (aluminum nitride base) having a radius of 50 mm and a thickness of 8 mm. The provided substrate 10 was obtained.

  In the above description, the configuration in which the electrode layer 20 is provided on the one main surface side with respect to the flow path 11 inside the base body 10 has been described. The structure which provides a layer may be sufficient. Moreover, although the external shape of the electrostatic chucks 1 and 1A is a disk shape, the shape is not limited to this, and may be a rectangular plate shape or other polygonal shape as long as the sample can be held with a sufficient holding force. There may be. In addition, although it has been described that the intermediate layer 13 may have a plurality of layers, the upper layer 12, the lower layer 14, and the outermost layer 13 may have a plurality of layers in the same manner as the intermediate layer 13.

In the above description, the electrostatic chuck has been described as an embodiment of the present invention. However, the present invention is not limited to this, and the present invention can also be applied to a vacuum chuck by vacuum suction without providing the electrode layer 20. In the mode applied to the vacuum chuck, in addition to the flow path 11, another flow path is provided inside the base body 10, and opens toward one main surface of the base body 10, and a plurality of suction holes communicating with the other flow paths are provided. The other channel may be connected to a vacuum pump and the other channel may be in a vacuum state. Similarly to the electrostatic chuck, the flow path 11 is configured to flow a heat medium that exchanges heat with the sample in order to cool or heat the sample held by vacuum suction. A through hole that penetrates the substrate 10 in the thickness direction is provided at a position other than the flow path 11 without providing another flow path, and is connected to the vacuum pump through an opening facing the surface opposite to the surface that holds the sample. The inside of the through hole may be in a vacuum state.
The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all points, and the scope of the present invention is shown in the scope of claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the claims are within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1,1A Electrostatic chuck 10 Base | substrate 10a Corner | angular part 10b Flat part 11 Flow path 11a, 11b Opening 12 Upper layer 13 Intermediate layer 13a 1st intermediate layer 13b 2nd intermediate layer 14 Lower layer 15 Outermost layer 20 Electrode layer 21 Positive electrode 22 Negative electrode 30, 30A Coating film 31 First coating film 32 Second coating film 121, 131, 132, 141 Inner surface

Claims (7)

A base body in which a plurality of ceramic layers are laminated and a flow path having a rectangular cross-sectional shape perpendicular to the longitudinal direction is provided inside;
And a coating film that covers an inner surface of a corner in a cross-sectional shape perpendicular to the longitudinal direction of the flow path.   The sample holder according to claim 1, wherein the coating film is provided so as to further cover a portion of the inner surface of the flow path other than the inner surface of the corner.   The sample holder according to claim 1, further comprising an electrode layer provided inside the substrate.   The sample holder according to claim 1, wherein the coating film is made of a metal material.   The sample holder according to claim 4, wherein a part of the coating film is exposed to the outside of the substrate.   6. The sample holder according to claim 5, wherein a part of the coating film is exposed to the outside of the substrate from the opening of the flow path.   6. The sample holder according to claim 5, wherein a part of the coating film is located between the plurality of ceramic layers and is exposed to the outside of the substrate at an outer peripheral end surface of the substrate.

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