JP2022176701A - holding device - Google Patents

Abstract

To provide a holding device capable of controlling a temperature of an object with high accuracy while reducing the generation of an abnormal discharge.SOLUTION: A holding device 100 comprises: a ceramic substrate 10 having a first front surface S1 that holds a wafer W and a second front surface S2 that is positioned at the side opposite to the first front surface S1; a base member 20 having a third front surface S3 that is positioned at the side opposite to the ceramic substrate 10 so as to be bonded to the second front surface S2; and a bonding member 30 that is arranged between the ceramic substrate 10 and the base member 20. In the holding device in which a flow channel 60 communicating between an outflow hole 61 provided to the first front surface S1 and an inflow hole 63 provided to the third front surface S3 so that a fluid can be moved is formed, a porous ceramic region 65 having a sparse area 65A and a dense area 65B having a void rate lower than that of the sparse area 65A and arranged in the first front surface S1 side from the sparse area 65A is provided to the flow channel 60.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a holding device for holding an object.

As an example of the holding device, an electrostatic chuck described in Patent Document 1 below is known. The electrostatic chuck includes a chuck body having a back surface and a chuck surface, an electrode within the chuck body, and a plurality of conduits extending between and providing fluid communication between the back surface and the chuck surface. and each conduit includes a porous region therein integral with and extending into the chuck body. When plasma processing or the like is performed on a wafer held on the chuck surface, a gas such as helium gas, which is a heat transfer fluid, is sent from the back surface to the chuck surface through a pipe in order to improve the temperature controllability of the chuck surface. When a wafer or the like is processed in the apparatus, an abnormal electrical discharge (arc discharge) may occur inside the conduit positioned between the wafer or the like and the metal member included in the electrostatic chuck. In the electrostatic chuck of No. 1, the occurrence of abnormal discharge is reduced by providing the porous region in the conduit.

By the way, when an object such as a wafer is held by a holding device or the held object is processed, impurities in the device and foreign matter such as ceramic pieces generated by friction between the wafer and the chuck surface are removed. , may fall into the pipeline for gas distribution. In the electrostatic chuck as described above, when a foreign object that has fallen into the pipe penetrates into the porous region, gas clogging occurs and the pressure drops, preventing the gas from being sufficiently supplied from the back surface to the chuck surface side. There was a possibility that the temperature controllability of the object would deteriorate.

Japanese Patent No. 4959905

In view of the above situation, an object of the present technology is to provide a holding device that can control the temperature of an object with high accuracy while reducing the occurrence of abnormal discharge.

A holding device according to the present disclosure includes a ceramic substrate having a first surface for holding an object and a second surface opposite to the first surface; (1) a base member having a third surface located opposite to the ceramic substrate, and a bonding material disposed between the ceramic substrate and the base member; A channel is formed in the ceramic substrate and the base member, and allows a fluid to movably communicate between an outflow hole provided on the first surface and an inflow hole provided on the third surface, or (2) The ceramic substrate is formed with a flow path for movably communicating a fluid between an outflow hole provided on the first surface and an inflow hole provided on the second surface, and the flow path is provided with a porous ceramic region, and the porous ceramic region includes a sparse region and a dense region having a lower porosity than the sparse region and arranged closer to the first surface than the sparse region. , provided.

According to the present disclosure, it is possible to provide a holding device capable of controlling the temperature of an object with high accuracy while reducing the occurrence of abnormal discharge.

FIG. 1 is a perspective view schematically showing a schematic configuration with a part of the holding device according to Embodiment 1 cut away. FIG. 2 is a cross-sectional view schematically showing the outline of the internal structure of the holding device. 3 is a cross-sectional view showing an enlarged part of FIG. 2. FIG. FIG. 4 is a cross-sectional view schematically showing an example of the state of porous regions formed in a channel. FIG. 5 is a cross-sectional view schematically showing the outline of the internal structure of the holding device according to the second embodiment. FIG. 6 is a cross-sectional view showing an enlarged part of FIG. FIG. 7 is a cross-sectional view showing an enlarged part of a holding device according to another embodiment. FIG. 8 is a cross-sectional view showing an enlarged part of a holding device according to another example of another embodiment. FIG. 9 is a cross-sectional view showing an enlarged part of a holding device according to still another example of another embodiment. FIG. 10 is a cross-sectional view of a holding device according to still another example of another embodiment.

[Description of Embodiments of the Present Disclosure]
First, the embodiments of the present disclosure are listed and described.
<1> A holding device according to the present disclosure includes a ceramic substrate having a first surface for holding an object and a second surface located on the opposite side of the first surface, and the second surface of the ceramic substrate. a base member disposed on the side, the base member having a third surface located on the opposite side of the ceramic substrate; and a bonding material disposed between the ceramic substrate and the base member; (1) The ceramic substrate and the base member are formed with a flow path for movably communicating a fluid between an outflow hole provided on the first surface and an inflow hole provided on the third surface. or (2) the ceramic substrate is formed with a flow path for movably communicating a fluid between an outflow hole provided on the first surface and an inflow hole provided on the second surface, A porous ceramic region is provided in the flow path, and the porous ceramic region has a lower porosity than the sparse region and the sparse region and is arranged closer to the first surface than the sparse region. a dense area;

According to the above configuration <1>, a porous ceramic region having a sparse region and a dense region is arranged in the channel for supplying gas from the third surface side to the first surface. The dense region positioned on the first surface side makes it difficult for foreign matter resulting from processing of the object to enter into the interior of the porous ceramic region, thereby reducing gas clogging. Further, by arranging the sparse area closer to the third surface than the dense area, the occurrence of abnormal discharge during processing of the object can be prevented without significantly increasing the pressure loss of the gas introduced from the third surface side. can be reduced. As a result, according to the holding device having the above configuration, the temperature of the object can be controlled with high accuracy by stably supplying the gas to the first surface side while reducing the occurrence of abnormal discharge.

<2> In the holding device of <1> above, the extension width of the dense area in the direction from the first surface to the third surface is smaller than the extension width of the sparse area. According to the configuration <2>, the extension width in the direction from the first surface to the third surface, that is, the thickness of the dense region is formed to be smaller (thinner) than the thickness of the sparse region. As a result, the gas pressure loss due to the presence of the porous region can be kept relatively small.

<3> In the holding device of <1> or <2> above, the dense region and the sparse region are arranged between the first surface and the second surface. According to the configuration <3>, the dense region and the sparse region, which are the porous ceramic regions, are arranged between the first surface and the second surface, that is, in the ceramic substrate made of the same material as the porous ceramic region. As a result, it is possible to form a dense area and a sparse area in the holding device, which have high adhesion to the peripheral structure and excellent durability.

<4> In the holding device according to any one of <1> to <3> above, the ceramic substrate includes a first portion including the first surface, a heater electrode formed of a resistance heating element, and the second surface. and a joining portion joining the first portion and the second portion. In the holding device having the structure <4>, for example, the second portion including the heater electrode is formed and joined to the base member, and the electric resistance of the heater electrode is adjusted while supplying power to the heater electrode and cooling the base member. After that, it can be manufactured by joining the second part and the first part. In such a holding device, the electric resistance of the heater electrode can be easily adjusted in the manufacturing process, so the temperature distribution on the first surface can be controlled with high precision. By applying the present technology to such a holding device, it is possible to obtain a holding device capable of controlling the temperature of an object with extremely high accuracy.

[Details of the embodiment of the present disclosure]
A specific example of the holding device of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to these examples, but is indicated by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims. Part of each drawing shows the X-axis, Y-axis, and Z-axis of an orthogonal coordinate system XYZ, and the directions of the axes are drawn in the same direction in each drawing. In the following description, the Z-axis direction is the vertical direction, the upper side of FIG. 2 is the upper side, and the lower side of FIG. . Further, with respect to a plurality of identical members, one member may be given a reference numeral and the other members may be omitted. The relative size and arrangement of members in each drawing are not necessarily accurate, and some members have been changed in scale or the like for convenience of explanation.

<Details of Embodiment 1>
(Holding device)
A holding device 100 according to the present embodiment will be described below with reference to FIGS. 1 to 4. FIG. The holding device 100 is an electrostatic chuck that attracts and holds an object (eg, semiconductor wafer W) by electrostatic attraction while heating the object (eg, semiconductor wafer W) to a predetermined processing temperature (eg, 50° C. to 400° C.). An electrostatic chuck is used as a table on which a wafer W is placed, for example, in a plasma etching process in a decompressed chamber.

FIG. 1 is a diagram schematically showing a schematic configuration of a holding device 100. As shown in FIG. The holding device 100 includes a disk-shaped ceramic substrate 10 and a similarly disk-shaped base member 20 . The diameter of the base member 20 is larger than that of the ceramic substrate 10. For example, if the ceramic substrate 10 is disk-shaped with a diameter of 300 mm and a thickness of 3 mm, the base member 20 can be disk-shaped with a diameter of 340 mm and a thickness of 20 mm. Both the ceramic substrate 10 and the base member 20 are generally disk-shaped, and may be provided with unevenness or the like for alignment. The ceramic substrate 10 and the base member 20 are arranged in the vertical direction and joined by a joining material 30 . A first surface S1 on the upper side of the ceramic substrate 10 serves as an attraction surface for attracting and holding the wafer W, and a second surface S2 on the lower side of the ceramic substrate 10 is bonded to the base member 20 via the bonding material 30. . A lower surface of the base member 20 is referred to as a third surface S3.

(ceramic substrate)
As also shown in FIG. 2, the ceramic substrate 10 is arranged such that its first surface S1 and second surface S2 are substantially perpendicular to the Z-axis. The ceramic substrate 10 is an insulating substrate, and is made of ceramics containing, for example, aluminum nitride (AlN) or alumina (Al ₂ O ₃ ) as a main component. In addition, the main component here means the component with the highest content ratio (weight ratio).

As shown in FIG. 2, inside the ceramic substrate 10, the chuck electrode 40 is arranged on the upper side, that is, the first surface S1 side, and the ceramic substrate 10 is heated below the chuck electrode 40, that is, on the second surface S2 side. A heater electrode 50 made of a resistance heating element is arranged for heating. The chuck electrode 40 and heater electrode 50 are made of a conductive material containing, for example, tungsten or molybdenum. In this embodiment, the chuck electrode 40 has a planar shape substantially parallel to the first surface S1. The heater electrodes 50 are electrodes extending along a plane substantially parallel to the first surface S1, and are arranged so as to form, for example, a spiral or concentric linear pattern when viewed from above. The chuck electrode 40 and the heater electrode 50 are each connected to a power supply through terminals or the like. Electric power is supplied to the heater electrode 50 as necessary, thereby heating the ceramic substrate 10 and heating the wafer W held on the first surface S1 of the ceramic substrate 10 .

As shown in FIGS. 1 and 2, the first surface S1 of the ceramic substrate 10 is provided with a plurality of outflow holes 61. As shown in FIG. The outer peripheral edge of the first surface S1 is formed to protrude slightly higher than the inner peripheral portion. A gap G is formed between the wafer W and the first surface S1. The ceramic substrate 10 is formed with a ceramic side flow path 60C (perforating the interior of the ceramic substrate 10 in the vertical direction) that communicates with the outflow hole 61 and opens to the second surface S2.

In this embodiment, the ceramic-side channel 60C includes a plane-parallel channel portion 60CT extending in the horizontal direction (parallel to the first surface S1). The ceramic-side channel 60C also includes a first connection portion 60CV1 extending vertically (perpendicular to the first surface S1) to connect the outflow hole 61 and the plane-parallel channel portion 60CT, and a vertical direction (perpendicular to the first surface S1). and a second connecting portion 60CV2 extending vertically) to connect the surface-parallel channel portion 60CT and the bonding material internal channel 60J described later. In the present embodiment, the plane-parallel channel portion 60CT is arranged between the heater electrode 50 and the second surface S2 in the vertical direction. The shapes of the outflow holes 61 and the openings in the second surface S2, and the cross-sectional shape of the ceramic-side channel 60C are not limited, but can be substantially circular, for example. In the present embodiment, the diameter of the outflow holes 61 is formed to be smaller than the cross-sectional diameter of the majority of the ceramic-side channel 60C, and a plurality of outflow holes 61 communicate with one ceramic-side channel 60C. (See FIG. 3, etc.).

(bonding material)
As the bonding material 30, for example, a silicone-based organic bonding agent, an inorganic bonding agent, or a bonding sheet containing an Al-based metal adhesive can be used. The bonding material 30 preferably has high adhesive strength to both the ceramic substrate 10 and the base member 20, and also has high heat resistance and thermal conductivity. In the bonding material 30, a hole is provided at a position facing the opening at the lower end of the second connection portion 60CV2 formed in the ceramic substrate 10, and as shown in FIG. A jointing material inner flow path 60J is formed.

(base member)
As shown in FIG. 2 and the like, the base member 20 is joined to the lower side of the ceramic substrate 10, that is, the second surface S2 side, with a joining material 30. As shown in FIG. A third surface S3 located on the opposite side of the ceramic substrate 10 is arranged substantially perpendicular to the Z-axis. The base member 20 can be mainly composed of, for example, aluminum, an aluminum alloy, a composite of metal and ceramics (Al--SiC), or ceramics (SiC). As described above, the base member 20 has a disc shape with a diameter larger than that of the ceramic substrate 10, and the entire ceramic substrate 10 is placed thereon.

As shown in FIGS. 1 and 2, a coolant passage 21 is formed inside the base member 20 . Plasma heat is cooled by flowing a coolant such as water or fluorine-based inert liquid through the coolant path 21 . When the coolant flows through the coolant path 21, the base member 20 is cooled, the ceramic substrate 10 is cooled by heat conduction through the bonding material 30, and the wafer W held on the first surface S1 of the ceramic substrate 10 is cooled. be. The temperature of the wafer W can be controlled by adjusting the coolant flow.

As shown in FIGS. 1 and 2, the third surface S3 of the base member 20 is provided with a plurality of inflow holes 63 into which gas flows. Inside the base member 20, there extends vertically (perpendicularly to the first surface S1) and communicates the bonding material internal flow path 60J with the inflow hole 63 (which penetrates the interior of the base member 20 in the vertical direction). ) A base-side channel 60B is formed.

(Flow path)
The holding device 100 has the first surface S1 and the third surface S1 and the third surface S1 and the third surface penetrating vertically through the inside of the holding device 100 by the above-described ceramic side flow path 60C, bonding material inner flow path 60J, and base side flow path 60B. A channel 60 is formed that opens to S3. The flow path 60 is formed so that the fluid can move inside it over the entire length. An inert gas such as helium gas, which is a heat transfer fluid, flows through the flow path 60 . The gas that has flowed in through the inflow hole 63 of the third surface S3 flows out of the outflow hole 61 of the first surface S1 through the flow path 60, and fills the gap G between the ceramic substrate 10 and the wafer W. FIG. Thereby, the temperature of the first surface S1 is easily transmitted to the wafer W, and the temperature controllability of the wafer W is improved.

(porous ceramic region)
As shown in FIG. 2, in the holding device 100, a porous ceramic region 65 is formed inside the channel 60 and between the first surface S1 and the third surface S3. As shown in FIG. 3, in this embodiment, the porous ceramic region 65 is formed between the first surface S1 and the second surface S2, that is, in the ceramic side channel 60C. More specifically, a portion of the first connection portion 60CV1 positioned between the chuck electrode 40 and the heater electrode 50 in the vertical direction is formed to have a larger diameter than other portions of the first connection portion 60CV1. A porous ceramic region 65 is formed in the large diameter portion. Formation of the porous ceramic region 65 in the flow path 60 reduces the occurrence of abnormal discharge during processing of the wafer W, as will be described later.

FIG. 4 is a diagram schematically showing an example of an XY section of the porous ceramic region 65. As shown in FIG. A large number of voids P are formed in the porous ceramic region 65 formed inside the ceramic-side channel 60C by arranging a porous body M made of an insulating ceramic material. The shape, size, and arrangement of the voids P formed by the porous body M are not particularly limited as long as the fluid can move vertically in the porous ceramic region 65. For example, as shown in FIG. Voids P having irregular sizes and irregular shapes may be arranged at random. The porosity, which is the ratio of the voids P in the porous ceramic region 65, can be calculated based on the area of the voids P per unit area, for example, by analyzing an electron microscope image of the cross section of the porous ceramic region 65. In order to smoothly supply gas from the third surface S3 side to the first surface S1 side, the porosity of the porous ceramic region 65 is preferably high. Moreover, in order to reduce the occurrence of abnormal discharge and the entry of foreign matter, which will be described later, it is preferable that the gap P in the porous ceramic region 65 is small.

As shown in FIG. 3, the area below the porous ceramic area 65 is a sparse area 65A having a relatively high porosity. By doing so, it is possible to effectively reduce the occurrence of abnormal discharge while suppressing gas pressure loss. On the other hand, the upper side (first surface S1 side) of the porous ceramic region 65 is a dense region 65B having a lower porosity than the sparse region 65A. The porosity of the dense region should be 0.50 to 0.90 times the porosity of the sparse region. By doing so, it is possible to effectively reduce the intrusion of foreign matter into the inside of the porous ceramic region 65 without greatly hindering the gas supply. The porosity of the entire porous ceramic region 65 is preferably 30% or more and 70% or less, more preferably 40% or more and 60% or less. With such a range, the gas can be supplied from the third surface S3 side to the first surface S1 while securing sufficient strength for the porous ceramic region 65 .

As shown in FIG. 3, in this embodiment, in the porous ceramic region 65, the thickness (vertical extension width) TB of the dense region 65B is set to be smaller than the thickness TA of the sparse region 65A. (TB<TA). By setting in this way, it is possible to effectively reduce the occurrence of abnormal discharge while suppressing gas pressure loss. Also, the thickness TB of the dense region 65B is set to 0.1 times or more and 0.9 times or less the thickness TA of the sparse region 65A. Within this range, it is possible to effectively reduce the intrusion of foreign matter into the interior of the porous ceramic region 65 without greatly hindering the gas supply.

A method for forming the porous ceramic region 65 is not particularly limited, and various methods can be adopted. For the porous ceramic region 65 of the present embodiment, for example, a cylindrical porous body M having a different porosity in the axial direction is produced, and in the manufacturing process of the ceramic substrate 10, the large diameter portion provided in the first connection portion 60CV1 It can be formed by fitting.

(Use of holding device)
The holding device 100 is used, for example, as part of a semiconductor manufacturing apparatus. When the wafer W is placed on the first surface S1 of the holding device 100 installed in the chamber of the semiconductor manufacturing apparatus, and power is supplied from the power source to the chuck electrode 40, an electrostatic attraction is generated to generate the first surface S1. , the wafer W is sucked. When the raw material gas is introduced into the chamber and a voltage is applied, plasma is generated and the wafer W is processed.

When the wafer W is processed, the wafer W is heated through the ceramic substrate 10 when power is supplied from the power supply to the heater electrode 50 . On the other hand, when the coolant flows through the coolant path 21, the wafer W is cooled. At this time, the heat-conducting gas is introduced from the inflow hole 63 of the third surface S3, and the gas that has flowed through the flow path 60 flows out from the outflow hole 61 of the first surface S1. By filling the formed gap G, the temperature of the wafer W can be controlled with high accuracy.

When plasma is generated to process the wafer W as described above, an abnormal electrical discharge (arc discharge) may occur. For example, between the wafer W and the base member when a metallic base member is used, and between the wafer W and the bonding material when the ceramic substrate and the base member are bonded with a bonding material containing a metal adhesive. Electric discharges can occur in existing spaces. In the holding device 100, the insulating porous ceramic region 65 is arranged in the gas channel 60, so that the occurrence of abnormal discharge in the gas channel 60 is reduced.

(Effect of this embodiment)
A holding device 100 according to this embodiment includes a ceramic substrate 10 having a first surface S1 for holding a wafer (object) W and a second surface S2 located on the opposite side of the first surface S1; A base member 20 arranged on the side of the second surface S2 of the ceramic substrate 10 and having a third surface S3 located on the opposite side of the ceramic substrate 10, the ceramic substrate 10 and the base member 20 The ceramic substrate 10 and the base member 20 have an outflow hole 61 provided on the first surface S1 and an inflow hole provided on the third surface S3. A flow path 60 is formed to allow a fluid to move between the flow path 63 and the flow path 60. The flow path 60 is provided with a porous ceramic region 65. The porous ceramic region 65 includes the sparse region 65A and the sparse region 65A. and a dense region 65B having a lower porosity than the region 65A and arranged closer to the first surface S1 than the sparse region 65A.

When the wafer W is processed, if foreign matter such as impurities or ceramic pieces in the chamber falls into the flow path 60, gas clogging occurs in the porous ceramic region 65, and the gas supply to the gap G becomes insufficient, resulting in poor temperature controllability. may decline. In this regard, in the holding device 100 according to the present embodiment, the dense region 65B is arranged on the first surface S1 side, so that foreign matter caused by processing of the object such as the wafer W is prevented from entering the inside of the porous ceramic region 65. It's getting harder to get into. More specifically, even when foreign matter falls from the outflow hole 61 into the channel 60, most of the foreign matter stays on the upper surface of the dense region 65B. During the processing of the wafer W, the gas is flowed from the third surface S3 side to the first surface S1 side in the channel 60, and the foreign matter existing on the upper surface of the dense region 65B enters the inside of the porous ceramic region 65. is suppressed. As a result, gas clogging of the porous ceramic region 65 due to intrusion of foreign matter is reduced.

Here, if the whole area of the porous ceramic region 65 for reducing the occurrence of abnormal discharge is made the dense region 65B into which foreign matter is difficult to enter, the pressure loss of the gas in the porous ceramic region 65 increases, and the first surface S1 and the wafer The gap G between W may not be supplied with sufficient gas. In this regard, the holding device 100 according to the present embodiment forms the sparse region 65A having a large porosity in the region closer to the third surface S3 than the dense region 65B, thereby minimizing gas pressure loss due to the porous ceramic region 65. It is configured to be able to reduce the occurrence of abnormal discharge when processing the wafer W while keeping it small.

As a result, according to the holding device 100, the temperature of the wafer (object) W can be controlled with high accuracy by stably supplying the gas to the first surface S1 side while reducing the occurrence of abnormal discharge. .

Further, in the holding device 100 according to the present embodiment, the extension width of the dense region 65B in the direction from the first surface S1 toward the third surface S3 (thickness TB of the dense region 65B) is equal to that of the sparse region 65A. (thickness TA of sparse region 65A).

In the holding device 100 of the present embodiment, the extension width in the vertical direction (the direction from the first surface S1 to the third surface S3) of the dense region 65B, that is, the thickness TB is smaller than the thickness TA of the sparse region 65A. )It is formed. As a result, the gas pressure loss due to the presence of the porous ceramic region 65 can be kept relatively small.

Further, in the holding device 100 according to this embodiment, the dense region 65B and the sparse region 65A are arranged between the first surface S1 and the second surface S2.

In the holding device 100 of the present embodiment, the dense region 65B and the sparse region 65A, which are the porous ceramic regions 65, are located between the first surface S1 and the second surface S2, that is, the ceramic substrate made of the same material as the porous ceramic regions 65. Placed in 10. As a result, the dense area 65B and the sparse area 65A having high adhesion to the peripheral structure and excellent durability can be formed inside the holding device 100 .

<Details of Embodiment 2>
The holding device 200 according to this embodiment will be described below with reference to FIGS. 5 and 6. FIG. The holding device 200 according to this embodiment differs from the holding device 100 according to the first embodiment in the structure of the ceramic substrate 210 and the structure of the channel 260 including the porous ceramic region 265 . In the following description, the description of the same configuration as that of the first embodiment is omitted.

(ceramic substrate)
As shown in FIG. 5, the ceramic substrate 210 according to this embodiment includes a first portion 211 including a first surface S1 and a second portion 212 including a second surface S2, which is the lower surface. The first surface S1 is the upper surface of the ceramic substrate 210, and is an attraction surface that attracts and holds an object such as a wafer W by electrostatic attraction. It is a side surface and a bonding surface that is bonded to the base member 220 via the bonding material 230 . The first portion 211 and the second portion 212 are arranged vertically and joined by a joint portion 213 . A chuck electrode 240 is arranged inside the first portion 211 , while a heater electrode 250 is arranged inside the second portion 212 . In addition, as shown in FIG. 5 , a sealing material OR is fitted around the outer circumference of the ceramic substrate 210 .

(Flow path)
As shown in FIG. 5, the holding device 200 has a ceramic side flow channel 260C, a bonding material inner flow channel 260J, and a base side flow channel 260B vertically penetrating the inside of the holding device 200 to provide a first A channel 260 is formed to communicate the outflow hole 261 of the surface S1 and the inflow hole 263 of the third surface S3. Of the flow paths 260 according to the present embodiment, the ceramic side flow path 260C and the bonding material internal flow path 260J vertically penetrate the ceramic substrate 210 or the bonding material 230, respectively. In addition, the base-side channel 260B includes a plane-parallel channel portion 260BT extending in the horizontal direction (parallel to the first surface S1) and a bonding material channel portion 260J extending in the vertical direction (perpendicular to the first surface S1). a first connection portion 260BV1 that connects the parallel channel portion 260BT, a second connection portion 260BV2 that extends in the vertical direction (perpendicular to the first surface S1) and connects the inflow hole 263 and the plane-parallel channel portion 260BT; including. In this embodiment, the plane-parallel flow path portion 260BT is arranged between the upper surface of the base member 220 and the coolant path 221 in the vertical direction.

(porous ceramic region)
As shown in FIG. 6, in this embodiment, the porous ceramic region 265 is formed in the ceramic side channel 260C of the channel 260. As shown in FIG. More specifically, a dense region 265B having a relatively low porosity is formed in the first flow path 260C1 formed in the first portion 211 of the ceramic substrate 210, and a second flow path 260C2 formed in the second portion 212 of the ceramic substrate 210. , and sparse regions 265A having a relatively high porosity are respectively arranged. In this embodiment, the porous ceramic region 265 is not disposed in the joint portion channel 260C3 formed in the joint portion 213, and the sparse region 265A and the dense region 265B are separated from each other in the ceramic side channel 260C. are distributed.

(Manufacture of holding device)
The holding device 200 according to this embodiment can be manufactured, for example, as follows.
First, the second portion 212 including the heater electrode 250 formed in a predetermined pattern and the base member 220 having the coolant passage 221 formed thereon are manufactured and joined with the joining material 230 . In this state, the temperature distribution of the upper surface of the second portion 212 is measured while heating the second portion 212 by supplying power to the heater electrode 250 and cooling the base member 220 by flowing a coolant. Depending on the measurement results, the electrical resistance is adjusted by, for example, partially removing the heater electrode 250 from above the second portion 212 . After that, the separately manufactured first portion 211 is joined to the upper surface of the second portion 212 via the joining portion 213 to obtain the holding device 200 .

In manufacturing the retainer 200 as described above, the porous ceramic regions 265 can be formed, for example, when the second portion 212 and the first portion 211 are made. Specifically, by fitting a prefabricated porous body into the large-diameter portion of the second channel 260C2 or the first channel 260C1, the sparse region 265A and the dense region 265B can be formed.

(Effect of this embodiment)
As described above, in the holding device 200 according to the present embodiment, the ceramic substrate 210 includes the first portion 211 including the first surface S1, the heater electrode 250 formed by the resistance heating element, and the second surface S2. and a joining portion 213 joining the first portion 211 and the second portion 212 .

The holding device 200 according to the present embodiment can measure the electrical resistance of the heater electrode 250 with high accuracy compared to a conventional holding device manufactured by bonding a ceramic substrate including a heater electrode and a chuck electrode to a base member after manufacturing the substrate. can be easily adjusted. Also, the adjustment can be made in consideration of variations in the electrical resistance of the heater electrode caused by firing during the manufacture of the ceramic substrate. Therefore, in the holding device 200, it is possible to improve the temperature controllability as compared with the conventional holding device. By applying the present technology to such a holding device 200, it is possible to obtain a holding device capable of controlling the temperature of the wafer W with very high accuracy.

<Other embodiments>
(1) The porous ceramic region may be formed in a region including outflow holes provided on the first surface S1 of the ceramic substrate. For example, like the ceramic substrate 310 shown in FIG. 7, when forming the porous ceramic region 365 in the first connection portion 360CV1 that connects the plane-parallel channel portion 360CT and the outflow hole 361, The coarse area 365A and the dense area 365B can be arranged in the provided large-diameter portion, and the dense area 365B can also be arranged in the small-diameter portion from the large-diameter portion to the outflow hole 361. FIG. In this way, entry of foreign matter from the first surface S1 side is suppressed at the inlet at the upper end of the flow path 360, so gas clogging of the porous ceramic region 365 can be reduced more effectively. When the porous ceramic region 365 is formed also in the small-diameter portion reaching the outflow hole 361, the area of the outflow hole 361 and the cross-sectional area of the small-diameter portion are reduced in order to avoid an increase in gas pressure loss. It is preferable to set it as large as possible.

(2) In the porous ceramic region, a dense region having a sufficiently low porosity with respect to the sparse region is arranged on the first surface S1 side of the sparse region. does not matter. As described in the first embodiment, the sparse regions 65A and the dense regions 65B may be formed so as to be in contact with each other. may be formed. Also, the boundary between the sparse area and the dense area need not be clear. For example, as in the ceramic substrate 410 shown in FIG. 8, when the porous ceramic region 465 is arranged in the large-diameter portion provided in the ceramic-side channel 460C, from the sparse region 465A having a predetermined porosity, the upper portion of the sparse region 465A The porous ceramic region 465 may be formed such that the porosity gradually decreases toward the dense region 465B located (on the first surface S1 side).

(3) Part or all of the porous ceramic region may be formed inside the base member. For example, like the ceramic substrate 510 shown in FIG. 9, a sparse region 565A is formed in a part of the base member side flow path 560B provided inside the base member 520, and the upper side of the sparse region 565A (first surface S1 side) is formed. ) and provided inside the ceramic substrate 510, the dense region 565B may be formed in the ceramic side flow channel 560C. Alternatively, both the sparse area and the dense area may be formed in the base member side channel.

(4) The channel does not have to be formed in the base member. For example, in the holding device 600 shown in FIG. 10, a channel 660 is formed to communicate an outflow hole 661 provided on the first surface S1 of the ceramic substrate 610 and an inflow hole 662 provided on the second surface S2. , and no flow path is formed in the base member 620 . A groove 664 is formed in the second surface S2 of the ceramic substrate 610 from the inflow hole 662 toward the outer circumference, and the end of the groove 664 opens to the side surface of the holding device 600 so that the gas is introduced through this opening. It has become. By applying the present technology to such a holding device 600 and forming a porous ceramic region 665 including a coarse region and a dense region in the flow path 660, the effect of the present technology can be obtained.

(5) The base member is not limited to one in which coolant channels are formed. As the base member, it is preferable to use a material having a high thermal conductivity and a cooling mechanism such as cooling fins.

(6) The above embodiments can be combined as appropriate. For example, a part of the ceramic substrate 10 described in Embodiment 1 may be provided with a porous ceramic region of the mode described in FIGS. 7 and 8. FIG. Alternatively, the holding device 200 having the configuration described in Embodiment 2 may be provided with the porous ceramic regions described in Embodiment 1 and FIGS. 7 to 9 .

(7) The material forming each member in the holding device of the above embodiment is merely an example, and each member may be formed of another material. Moreover, the manufacturing method of the holding device in the above embodiment is merely an example, and various modifications are possible.

(8) The present disclosure is not limited to the electrostatic chucks exemplified in the above embodiments, and can be similarly applied to other holding devices (for example, heating devices, etc.) that hold an object on the surface of a ceramic substrate. be.

100, 200, 600... Holding device 10, 210, 310, 410, 510, 610... Ceramic substrate 20, 220, 520, 620... Base member 21, 221... Coolant path 30, 230... Joining material 40, 240... Chuck electrode 50, 250 Heater electrodes 60, 260, 360, 660 Flow paths 60B, 260B, 560B Base side flow paths 60C, 260C, 460C, 560C Ceramic side flow paths 60CT, 360CT Plane parallel flow path portions (ceramic side flow path)
60CV1, 360CV1... First connection part (ceramic side flow path)
60CV2...Second connection portion (ceramic side flow path)
60J, 260J ... Bonding material flow paths 61, 261, 361, 661 ... Outflow holes 63, 263, 662 ... Inflow holes 664 ... Grooves 65, 265, 365, 465, 665 ... Porous ceramic regions 65A, 265A, 365A, 465A , 565A... Sparse area 65B, 265B, 365B, 465B, 565B... Dense area 211... First part 212... Second part 213... Joining part 260BT... Plane parallel channel part (base side channel)
260BV1... First connection part (base side flow path)
260BV2...Second connecting portion (base-side channel)
260C1... First channel (ceramic side channel)
260C2...Second channel (ceramic side channel)
260C3 ... Junction channel (ceramic side channel)
G...Gap M...Porous body P...Gap S1...First surface S2...Second surface S3...Third surfaces TA, TB...Thickness (extending width in the vertical direction)
W ... Wafer (object)
OR: sealing material

Claims (4)

a ceramic substrate having a first surface for holding an object and a second surface opposite the first surface;
a base member disposed on the second surface side of the ceramic substrate, the base member having a third surface located on the opposite side of the ceramic substrate; and a base member disposed between the ceramic substrate and the base member. and
(1) The ceramic substrate and the base member are formed with a flow path for movably communicating a fluid between an outflow hole provided on the first surface and an inflow hole provided on the third surface. or (2) the ceramic substrate is formed with a flow path for movably communicating a fluid between an outflow hole provided on the first surface and an inflow hole provided on the second surface,
the channel is provided with a porous ceramic region,
The holding device, wherein the porous ceramic region includes a sparse region and a dense region having a lower porosity than the sparse region and arranged closer to the first surface than the sparse region. 2. The holding device according to claim 1, wherein an extension width of said dense area in a direction from said first surface to said third surface is smaller than an extension width of said sparse area. 3. The holding device according to claim 1 or 2, wherein the dense area and the sparse area are arranged between the first surface and the second surface. The ceramic substrate has a first portion including the first surface, a second portion including a heater electrode formed by a resistance heating element and the second surface, and the first portion and the second portion. 4. A retaining device according to any one of claims 1 to 3, comprising a joining portion joining the .

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