JP2020047747A - Holding device - Google Patents

Abstract

To improve the thermal conductivity between a plate member and a base member by improving the thermal conductivity of a joint portion while suppressing the occurrence of peeling between members of a holding device and cracking of the member.SOLUTION: A holding device includes a plate member having a first surface substantially orthogonal to the first direction, a base member having a cooling mechanism, and a joint portion that joins the plate member and the base member, and holds an object on the first surface of the plate member. The joint portion contains a joining material and fibers having a higher thermal conductivity than that of the joining material.SELECTED DRAWING: Figure 3

Description

  The technology disclosed in this specification relates to a holding device that holds an object.

  For example, in a semiconductor manufacturing apparatus, an electrostatic chuck is used as a holding device for holding a wafer. The electrostatic chuck includes, for example, a plate member made of ceramics, a base member made of metal, for example, a joining portion that joins the plate member and the base member, and a chuck electrode provided inside the plate member. The wafer is sucked and held on the surface of the plate-shaped member (hereinafter, referred to as “suction surface”) by using electrostatic attraction generated by applying a voltage to the chuck electrode.

  If the temperature of the wafer held on the suction surface of the electrostatic chuck does not reach the desired temperature, the accuracy of each processing (film formation, etching, etc.) on the wafer may be reduced. The ability to control the distribution is required. However, since the thermal conductivity of the material forming the joint tends to be lower than the thermal conductivity of the material forming the plate member and the base member, the thermal conductivity between the plate member and the base member tends to be lower. May be reduced. 2. Description of the Related Art Conventionally, a member (thermal connection member) in which a material having good heat conductivity is formed in a mesh shape and a member to which an adhesive is applied is disposed between a plate-shaped member and a base member of an electrostatic chuck. Thus, a technique for improving the thermal conductivity between the plate member and the base member is known (for example, see Patent Document 1).

JP-A-7-263527

  In the above-described conventional configuration, a member formed of a material having good thermal conductivity in a mesh shape does not have sufficient flexibility because the wire does not extend particularly in a direction parallel to the wire of the mesh. In the above-described conventional configuration, since the member having no sufficient flexibility is disposed between the plate member and the base member, the stress caused by the difference in thermal expansion between the plate member and the base member. Is not effectively mitigated, and there is a problem that peeling between members and cracking of members may occur.

  In addition, such a problem is not limited to the electrostatic chuck that holds a wafer using electrostatic attraction, but includes a plate-shaped member, a base member, and a joint, and an object on the surface of the plate-shaped member. This is a common problem in general for a holding device that holds the data.

  This specification discloses a technique capable of solving the above-described problem.

  The technology disclosed in this specification can be realized, for example, as the following modes.

(1) A holding device disclosed in the present specification includes a plate-shaped member having a first surface substantially perpendicular to a first direction and a second surface opposite to the first surface. A base member having a third surface, the third surface being located on the second surface side of the plate member, and having a cooling mechanism; and a base member having a cooling mechanism. A joining portion disposed between a second surface and the third surface of the base member to join the plate member and the base member, wherein the first surface of the plate member is provided. In the holding device for holding an object above, the joint includes a joining material and a fiber having a higher thermal conductivity than the thermal conductivity of the joining material.

  As described above, in the present holding device, the bonding portion contains a material having a higher thermal conductivity than the thermal conductivity of the resin material in the form of fibers, so that the bonding portion has good thermal conductivity and sufficient thermal conductivity. It has flexibility. Therefore, according to the present holding device, by ensuring good thermal conductivity in the first direction (that is, between the plate-shaped member and the base member via the joint), the first shape of the plate-shaped member can be improved. The responsiveness of the surface temperature (that is, the rate of temperature rise or the rate of temperature decrease) can be improved. Thereby, the rate of temperature rise and the rate of temperature decrease of the object held on the first surface of the plate member can be improved, and the processing efficiency of the object can be improved. Further, according to the present holding device, by the joint, the joint between the plate member and the base member is secured, and the stress due to the difference in thermal expansion between the plate member and the base member is effectively reduced. Due to (stress relaxation), deformation of the plate-like member due to thermal stress can be suppressed, and occurrence of peeling between members and cracking of the member can be suppressed.

(2) In the holding device, the average orientation direction of the fibers at the joint may be substantially parallel to a second direction orthogonal to the first direction. The heat transmitted to the fiber is more diffused in the fiber orientation direction (longitudinal direction). For this reason, if the orientation direction (longitudinal direction) of the fiber is substantially parallel to the second direction at the joining portion, in other words, the average orientation direction of the fiber as viewed in the second direction is substantially parallel to the second direction. Then, the heat transferred to the joint portion can be more effectively applied to the joint portion at the joint surface with the second surface of the plate member, the joint surface with the third surface of the base member, or the joint portion. It can be diffused in a second direction inside. That is, the thermal conductivity of the joint in the second direction is improved. Thereby, in the first surface of the plate-shaped member, a region which is likely to become a temperature singular point due to the influence of the base member located via the joint portion, for example, a cooling mechanism formed on the base member when viewed in the first direction Can be suppressed from becoming a low-temperature singular point. Therefore, according to the present holding device, it is possible to improve the uniformity of the temperature distribution on the first surface while securing the responsiveness of the temperature on the first surface of the plate-shaped member.

(3) In the holding device, a thermal conductivity of the joint in the second direction may be higher than a thermal conductivity of the joint in the first direction. For this reason, the heat transmitted to the joint portion can be more effectively applied to the joint portion at the joint surface with the second surface of the plate member, the joint surface with the third surface of the base member, or at the inside of the joint portion. In the second direction. That is, the thermal conductivity of the joint in the second direction is improved. Thereby, in the first surface of the plate-shaped member, a region which is likely to become a temperature singular point due to the influence of the base member located via the joint portion, for example, a cooling mechanism formed on the base member when viewed in the first direction Can be suppressed from becoming a low-temperature singular point. Therefore, according to the present holding device, it is possible to improve the uniformity of the temperature distribution on the first surface while securing the responsiveness of the temperature on the first surface of the plate-shaped member.

(4) In the holding device, the bonding portion may include a fiber-containing layer containing the fiber and a fiber-free layer that does not contain the fiber and that is disposed at a position different from the fiber-containing layer in the first direction. And a layer. Since the non-fiber-containing layer does not contain fibers, it has higher flexibility than the fiber-containing layer. As described above, in the present holding device, the joint has the fiber-containing layer having good thermal conductivity and the fiber-free layer having higher flexibility. Therefore, according to the present holding device, the responsiveness of the temperature of the first surface of the plate-shaped member is ensured, and the joining portion secures the jointability between the plate-shaped member and the base member. Stress relaxation between the base member and the base member can be ensured.

(5) In the holding device, in the first direction, the thickness of the fiber-containing layer may be larger than the thickness of the non-fiber-containing layer. Due to such a configuration, compared to a configuration in which all of the joints are made of the fiber-free layer or a configuration in which the fiber-free layer is thicker than the fiber-containing layer, a reduction in the thermal conductivity at the joint is suppressed. can do. Further, in the holding device, the thermal conductivity in the second direction can be higher than the thermal conductivity in the first direction in the entire joint. Therefore, according to the present holding device, the stress resilience between the plate-shaped member and the base member is ensured, and the temperature responsiveness of the first surface of the plate-shaped member (that is, the temperature rising rate or the temperature falling rate). Is suppressed, and the uniformity of the temperature distribution on the first surface of the plate-shaped member can be improved.

(6) The holding device further includes a heater electrode that is a resistance heating element disposed on the plate-shaped member, and in the first direction, the fiber-containing layer includes the plate-shaped member in the joint. It may be configured to be arranged on the member side. The portion of the joining portion that constitutes the plate-like member side provided with the heater electrode is a portion that may be exposed to high-temperature heat. This is because the heater electrode and the wafer are heated by heat or the like generated during processing. Since the fiber-containing layer contains the above-mentioned fibers, it has good heat resistance. This is because, in addition to the fiber itself having high heat resistance, the fiber-containing layer contains fibers, so that oxygen, which can cause deterioration of the resin material contained in the fiber-containing layer, passes through the fiber-containing layer. This is because it becomes difficult. In addition, radicals derived from oxygen deteriorate the resin material, but the fibers contained in the fiber-containing layer trap the radicals and deactivate the radicals, whereby the deterioration of the resin material can be suppressed. For this reason, it is possible to suppress the occurrence of peeling between the members due to the decomposition of the resin contained in the joint portion, and thus to suppress the non-uniform temperature distribution of the first surface of the plate-shaped member. be able to.

(7) In the holding device, the joint may have a shear adhesion strain of 40% or more. That is, the joint has a certain degree of resistance to shear fracture. For this reason, in the present holding device, due to the presence of the fiber in the bonding portion, while maintaining good thermal conductivity between the plate member and the base member, the difference in thermal expansion between the plate member and the base member is caused. It is possible to prevent the joint from being broken by the stress and the peeling from occurring between the members (between the joint and the plate member or between the joint and the base member). Therefore, according to the present holding device, the thermal conductivity (heat drawing characteristic) between the plate-shaped member and the base member is reduced due to the portion where the joint is broken or the member is separated, and In the first direction of the member, when viewed in the first direction, it is possible to suppress a region where a joint breakage or separation between members occurs and an overlapping region from becoming a high temperature singularity. Therefore, according to the present holding device, it is possible to improve the uniformity of the temperature distribution on the first surface while securing the responsiveness of the temperature on the first surface of the plate-shaped member.

(8) In the holding device, the bonding portion may have a Young's modulus of 10 MPa or less. In the present holding device, the joint has a certain degree of flexibility. For this reason, in the present holding device, due to the presence of the fiber in the bonding portion, while maintaining good thermal conductivity between the plate member and the base member, the difference in thermal expansion between the plate member and the base member is caused. The occurrence of warpage due to stress can be suppressed. Therefore, according to the present holding device, it is possible to suppress the processing speed (for example, the etching speed) for the target from becoming non-uniform or the processing depth from being restricted due to the warpage.

(9) In the holding device, the rigidity of the joint may be 4 MPa or less. In this holding device, the joint has a certain degree of flexibility, particularly in the shear direction. For this reason, in the present holding device, due to the presence of the fiber in the bonding portion, while maintaining good thermal conductivity between the plate member and the base member, the difference in thermal expansion between the plate member and the base member is caused. The occurrence of warpage due to stress can be suppressed. Therefore, according to the present holding device, it is possible to suppress the processing speed (for example, the etching speed) for the target from becoming non-uniform or the processing depth from being restricted due to the warpage.

(10) In the holding device, the joint may include a resin material. Therefore, according to the present holding device, the joint portion effectively secures the joining property between the plate-shaped member and the base member, and effectively reduces the stress due to the difference in thermal expansion between the plate-shaped member and the base member. And the occurrence of peeling between members and cracking of the members can be effectively suppressed. Further, according to the present holding device, since the joint includes the resin material, when a hole is formed in the joint, airtightness between the hole and the inside of the vacuum chamber is ensured. For this reason, it is possible to suppress a decrease in the degree of vacuum in the vacuum chamber due to the gas in the hole leaking into the vacuum chamber in which the holding device is placed. In the case where the plurality of holes are formed in the joint portion, airtightness between the holes is ensured, so that it is possible to suppress gas from being mutually mixed between the holes. .

  Note that the technology disclosed in the present specification can be realized in various forms, for example, a holding device, an electrostatic chuck, a vacuum chuck, and a method of manufacturing the same. is there.

FIG. 2 is a perspective view schematically showing an external configuration of the electrostatic chuck 100 according to the first embodiment. FIG. 2 is an explanatory diagram schematically showing an XZ cross-sectional configuration of the electrostatic chuck 100 according to the first embodiment. FIG. 3 is an explanatory diagram showing an XZ cross-sectional configuration of the electrostatic chuck 100 in an X1 part of FIG. 2 in an enlarged manner. FIG. 3 is an explanatory diagram schematically showing a configuration of a joining unit 30. It is explanatory drawing which shows typically the identification method of shear adhesion strain. It is explanatory drawing which shows the detailed structure near the joining part 30a in the electrostatic chuck 100a of 2nd Embodiment.

A. First embodiment:
A-1. Configuration of electrostatic chuck 100:
FIG. 1 is a perspective view schematically illustrating an external configuration of the electrostatic chuck 100 according to the first embodiment, and FIG. 2 is an explanatory diagram schematically illustrating an XZ cross-sectional configuration of the electrostatic chuck 100 according to the first embodiment. FIG. 3 is an explanatory diagram showing an enlarged XZ cross-sectional configuration of the electrostatic chuck 100 at a portion X1 in FIG. Each drawing shows XYZ axes orthogonal to each other for specifying the direction. In this specification, for the sake of convenience, the positive direction of the Z axis is referred to as an upward direction, and the negative direction of the Z axis is referred to as a downward direction. However, the electrostatic chuck 100 is actually installed in a direction different from such a direction. May be done.

  The electrostatic chuck 100 is a device that attracts and holds an object (for example, a semiconductor wafer W) by electrostatic attraction, and is used, for example, for fixing the wafer W in a vacuum chamber of a semiconductor manufacturing apparatus. The electrostatic chuck 100 includes a plate-shaped member 10 and a base member 20 arranged side by side in a predetermined arrangement direction (in this embodiment, a vertical direction (Z-axis direction)). The plate-shaped member 10 and the base member 20 are arranged such that the lower surface S2 of the plate-shaped member 10 (see FIG. 2) and the upper surface S3 of the base member 20 are opposed to each other in the above-described arrangement direction with a joint 30 described later interposed therebetween. Is done. That is, the base member 20 is arranged such that the upper surface S3 of the base member 20 is located on the lower surface S2 side of the plate-shaped member 10.

  The plate-shaped member 10 is a member having a substantially circular flat upper surface (hereinafter, referred to as “adsorption surface”) S1 that is substantially orthogonal to the above-described arrangement direction (Z-axis direction), for example, ceramics (for example, alumina or aluminum nitride). Etc.). The diameter of the plate member 10 is, for example, about 50 mm to 500 mm (generally about 200 mm to 350 mm), and the thickness of the plate member 10 is, for example, about 1 mm to 10 mm. The suction surface S1 of the plate member 10 corresponds to the first surface in the claims, the lower surface S2 of the plate member 10 corresponds to the second surface in the claims, and the Z-axis direction is This corresponds to the first direction in the claims. In this specification, a direction orthogonal to the Z-axis direction is referred to as a “plane direction”. The plane direction corresponds to the second direction in the claims.

  As shown in FIG. 2, a chuck electrode 40 formed of a conductive material (for example, tungsten, molybdenum, platinum, or the like) is arranged inside the plate-shaped member 10. The shape of the chuck electrode 40 as viewed in the Z-axis direction is, for example, substantially circular. When a voltage is applied to the chuck electrode 40 from a power supply (not shown), an electrostatic attraction is generated, and the wafer W is suction-fixed to the suction surface S1 of the plate member 10 by the electrostatic attraction.

  Inside the plate-shaped member 10, a heater electrode 50 formed of a resistance heating element containing a conductive material (for example, tungsten, molybdenum, platinum, or the like) is arranged. When a voltage is applied to the heater electrode 50 from a power supply (not shown), the heater electrode 50 generates heat, thereby heating the plate-like member 10 and warming the wafer W held on the suction surface S1 of the plate-like member 10. Can be Thereby, control of the temperature distribution of the wafer W is realized.

  The base member 20 is, for example, a plate member having the same diameter as the plate member 10 or a circular flat plate having a larger diameter than the plate member 10, and is formed of, for example, a metal (aluminum, an aluminum alloy, or the like). The diameter of the base member 20 is, for example, about 220 mm to 550 mm (normally, 220 mm to 350 mm), and the thickness of the base member 20 is, for example, about 20 mm to 40 mm. The upper surface S3 of the base member 20 corresponds to a third surface in the claims.

  The base member 20 is joined to the plate member 10 by a joint 30 disposed between the lower surface S2 of the plate member 10 and the upper surface S3 of the base member 20. The joint 30 includes, for example, a resin material (adhesive material). The thickness of the joint 30 is, for example, about 0.1 mm to 1 mm. The configuration of the joint 30 will be described later in detail.

  A coolant channel 21 is formed inside the base member 20. When a coolant (for example, a fluorine-based inert liquid or water) flows through the coolant channel 21, the base member 20 is cooled, and heat transfer between the base member 20 and the plate member 10 via the joint 30. The plate member 10 is cooled by the (heat drawing), and the wafer W held on the suction surface S1 of the plate member 10 is cooled. Thereby, control of the temperature distribution of the wafer W is realized. The coolant channel 21 corresponds to a cooling mechanism in the claims.

  As shown in FIG. 2, the electrostatic chuck 100 is formed with a pin insertion hole 140 extending vertically from the lower surface S <b> 4 of the base member 20 to the suction surface S <b> 1 of the plate-shaped member 10. That is, the pin insertion hole 140 includes the hole 26 that penetrates the base member 20 in the Z-axis direction, the hole 36 that penetrates the joint 30 in the Z-axis direction, and the hole 16 that penetrates the plate member 10 in the Z-axis direction. Are integral holes communicating with each other. The pin insertion hole 140 is a hole for inserting a lift pin (not shown) for pushing up the wafer W held on the suction surface S1 of the plate-shaped member 10 and separating the wafer W from the suction surface S1.

  Further, as shown in FIG. 2, the electrostatic chuck 100 increases the heat transfer between the plate member 10 and the wafer W to further enhance the controllability of the temperature distribution of the wafer W. A configuration is provided in which an inert gas (for example, helium gas) is supplied to a space existing between the surface S1 and the surface of the wafer W. That is, the electrostatic chuck 100 has a first gas passage hole 131 extending vertically from the lower surface S <b> 4 of the base member 20 to the upper surface of the joining portion 30, and communicates with the first gas passage hole 131 and has a plate-like shape. A second gas passage hole 132 is formed in the suction surface S1 of the member 10 and is open. The first gas passage hole 131 is an integrated hole in which a hole 25 that penetrates the base member 20 in the Z-axis direction and a hole 35 that penetrates the joint 30 in the Z-axis direction communicate with each other. Further, the lower end of the second gas passage hole 132 is an enlarged diameter portion 134 whose diameter is enlarged. In the enlarged diameter portion 134, a filling member (air permeable plug) 160 having air permeability is provided. Is filled. Further, inside the plate-shaped member 10, a horizontal flow path 133 communicating with the second gas flow path hole 132 and extending annularly in the plane direction is formed. When the helium gas supplied from the helium gas source (not shown) flows into the first gas passage hole 131, the helium gas that flows in is filled from the first gas passage hole 131 into the enlarged diameter portion 134. The gas flows through the inside of the filled gas-permeable member 160 into the second gas passage hole 132 inside the plate-shaped member 10, flows in the plane direction through the horizontal passage 133, and flows through the suction surface S 1. It is ejected from the gas ejection hole formed in the air. Thus, the helium gas is supplied to the space existing between the suction surface S1 and the surface of the wafer W.

A-2. Detailed configuration of the joint 30:
Next, with reference to FIGS. 3 and 4, a detailed configuration of the joint 30 that joins the plate member 10 and the base member 20 will be described.

  FIG. 4 is an explanatory diagram schematically showing the configuration of the joining section 30. The joint 30 includes a resin material 321. In the present embodiment, the joint 30 includes the resin material 321 as a main component. In addition, in this specification, a main component means the component whose volume content is more than 50 vol%.

  Various resin materials such as a silicone resin, an acrylic resin, and an epoxy resin can be used as the resin material 321 included in the joint portion 30, but it is preferable to use a silicone resin. Among resin materials, silicone resin is excellent in cold resistance, heat resistance and flexibility. Therefore, if a silicone resin is used as the resin material contained in the bonding portion 30, the cold resistance and heat resistance of the bonding portion 30 can be improved, and the electrostatic chuck 100 can be used in a wide temperature range, and the bonding can be performed. By extremely effectively relieving the stress due to the difference in thermal expansion between the plate-like member 10 and the base member 20 by the part 30, it is possible to extremely effectively suppress the occurrence of peeling between members and cracking of the members. Because it can be. Further, among silicone resins, it is more preferable to use an addition-curable silicone resin. Among silicone resins, addition-curable silicone resins do not generate volatile by-products during curing. Therefore, if an addition-curable silicone resin is used as the resin material contained in the joint portion 30, it is possible to suppress the generation of air bubbles in the joint portion 30 due to the by-product, and as a result, the presence of the air bubbles To suppress a decrease in thermal conductivity (heat-drawing characteristic) between the plate member 10 and the base member 20 due to the above, and a decrease in the uniformity of the temperature distribution on the suction surface S1 of the plate member 10. Can be. The resin material 321 corresponds to a bonding material in the claims.

  Further, the joint 30 includes a fiber 322 in addition to the resin material 321. Here, the fiber is a thin thread-like object, and more specifically, an average with respect to an average diameter (diameter in the case of a substantially circular cross section, diameter of a circle having the same cross-sectional area as the rectangular cross section in the case of a rectangular cross section). The object has a length ratio (aspect ratio) of 10 or more. The aspect ratio of the fiber 322 is, for example, preferably 20 or more, and more preferably 30 or more. The average diameter of the fibers 322 is, for example, preferably 2 μm or more and 200 μm or less, and more preferably 2 μm or more and 100 μm or less in order to form an adhesive sheet. The average length of the fibers 322 is preferably, for example, not less than 20 μm and not more than 30 mm. The material forming the fiber 322 is not particularly limited as long as the fiber has a higher thermal conductivity than the resin material 321 included in the joint 30. The thermal conductivity of the material constituting the fiber 322 is preferably, for example, 1 W / (m · K) or more, more preferably 5 W / (m · K) or more, and further preferably 10 W / (m · K). / (M · K) or more. In addition, the average diameter of the fiber 322 is in an arbitrary region in an SEM image (for example, 300 times) of the fiber 322 obtained by using FE-SEM (field emission scanning electron microscope, acceleration voltage 1.5 kV). This is the average value of the lengths of the included 100 fibers 322 in the lateral direction. The average length of the fiber 322 is an average value of the length in the longitudinal direction of 100 fibers 322 included in an arbitrary region in the SEM image (for example, 300 times) of the fiber 322 obtained as described above. The thermal conductivity can be measured with reference to JIS R1611, JIS A1412-1, JIS A1412-2, JIS A1412-3, and the like. Or you may measure using the thermal conductivity measuring device mentioned later.

As a material for forming the fibers 322, for example, inorganic fibers, metal fibers, carbon-based fibers, and the like can be used. Examples of the inorganic fibers include, for example, calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, alumina fiber, soda glass fiber, quartz glass fiber, rock wool (ie, containing silicon dioxide and calcium oxide as main components). Artificial mineral fibers) can be used. As the metal fiber, for example, stainless steel fiber, aluminum fiber, copper fiber, brass fiber, titanium fiber, and the like can be used. As the carbon-based fiber, a fibrous body in which carbon fiber carbon nanotubes, graphene, graphite, and the like are aggregated in a fibrous form can be used. The fibers 322 are more preferably inorganic fibers and carbon-based fibers, and still more preferably alumina fibers. Note that two or more kinds of the fibers 322 can be used in combination. When an addition-curable silicone resin is used as the resin material 321, carbon fibers may be used as the fibers 322 from the viewpoint of improving heat resistance. The thermal conductivity (W / (m · K)) as a raw material of the main material forming the fiber 322, that is, as a dense body instead of an aggregate of fibers is as follows.
Alumina: 21
Soda glass: 0.55 to 0.75
Quartz glass: 1.4
Stainless steel: 12
Aluminum: 230
Copper: 403
Brass: 106
Titanium: 22
Graphite: 80-230

  The content of the fibers 322 in the joint portion 30 is preferably, for example, not less than 2% by weight and not more than 30% by weight. When the content is less than 2% by weight, the effect of increasing the thermal conductivity of the joint portion 30 by the fiber 322 is small, and good heat between the plate member 10 and the base member 20 via the joint portion 30 is obtained. There is a tendency that conductivity cannot be ensured. On the other hand, if the content exceeds 30% by weight, the resin material 321 cannot be substantially blended, and the stress due to the difference in thermal expansion between the plate-shaped member 10 and the base member 20 tends not to be sufficiently reduced. . On the other hand, if the content is 2% by weight or more and 30% by weight or less, it is possible to secure good thermal conductivity between the plate member 10 and the base member 20 via the joint 30. In addition, since the joint 30 has sufficient flexibility, stress due to a difference in thermal expansion between the plate-shaped member 10 and the base member 20 can be reduced. The content is more preferably 3% by weight or more and 25% by weight or less, and still more preferably 5% by weight or more and 20% by weight or less.

  As shown in FIG. 4, the fibers 322 are not regularly woven and are dispersed in the resin material 321 of the joint portion 30. More preferably, at least a part of the fibers 322 is independently dispersed in the resin material 321 of the joint portion 30 for each fiber. Since the fibers 322 exist in the resin material 321 of the bonding portion 30 in the above-described form, the fibers 322 made of a nonwoven fabric or a fiber sheet can be used.

  Further, in the joint portion 30, the average orientation direction of the fibers 322 in the plane direction is substantially parallel to the plane direction. In other words, generally, the longitudinal direction of the fiber 322 substantially coincides with the surface direction, and exists in the XY plane. Here, the “average orientation direction of the fiber 322 in the planar direction” is the average angle between the longitudinal direction and the planar direction of the fiber 322 in the planar direction, and the “average orientation direction of the fiber 322 in the planar direction”. “The orientation direction is substantially parallel to the plane direction” means that the average angle between the average orientation direction and the plane direction of the fiber 322 in the plane direction is ± 20 °. In addition, from the viewpoint of improving the flexibility of the joint portion 30 in the XY plane, when viewed in the Z-axis direction, the fibers 322 are preferably not oriented in a specific direction in the XY plane. It may be bent inside. That is, when viewed in the Z-axis direction, the fibers 322 are preferably located in various directions (ie, random) on the XY plane. Note that the average orientation direction of the fibers 322 as viewed in the plane direction corresponds to the average orientation direction of the fibers in the claims.

  The average orientation direction of the fiber 322 as viewed in a plane direction can be determined, for example, by the following method. First, an XZ section parallel to the up-down direction in the joining section 30 is arbitrarily set, and an SEM image (for example, 300 times) of the FE-SEM (acceleration voltage 1.5 kV) is obtained in the XZ section. In the obtained SEM image, out of the fibers 322 included in an arbitrary region, the number n of fibers having a length Lf in the longitudinal direction of 50 μm or more is specified. A first virtual straight line VL1 approximating in the longitudinal direction of the specified fiber 322 is specified. Next, a second virtual straight line VL2 parallel to the surface direction is specified. Then, the minimum angle θ among the angles formed by the first virtual straight line VL1 and the second virtual straight line VL2 is specified. The minimum angle θ is specified for the specified n fibers 322. The average angle θav of the specified minimum angle θ is the average orientation direction of the fiber 322 in the planar direction. When the average angle θav is ± 20 ° or less, it can be said that the average orientation direction of the fibers 322 in the plane direction is substantially parallel to the plane direction.

  Further, the thermal conductivity of the joint 30 in the surface direction is higher than the thermal conductivity of the joint 30 in the Z-axis direction (thickness direction). In other words, the thermal conductivity in the surface direction of the joint 30 on the surface and inside of the joint 30 is superior to the thermal conductivity in the Z-axis direction (thickness direction). The bonding portion 30 has, for example, a thermal conductivity of 0.4 W / (m · K) or more and 50 W / (m · K) or less in the plane direction, and a Z-axis direction (thickness) with respect to the thermal conductivity in the plane direction. It is preferable that the ratio of the thermal conductivity in the direction is 1.5 or more and 10 or less.

The thermal conductivity of the joint 30 can be determined by, for example, a laser flash method. Specifically, the joint 30 is cut out, and a substantially rectangular parallelepiped sample having a length of 10 mm, a width of 10 mm, and a thickness of 1 mm is prepared so that the Z-axis direction (thickness direction) and the surface direction of the joint 30 can be understood. In the laser flash method, the surface of the manufactured sample is instantaneously and uniformly heated by a pulsed laser beam, and the temperature change on the back surface of the sample is measured by a radiation thermometer, thereby obtaining a thermal diffusivity in a thickness direction. In order to improve the absorption and emissivity of the laser energy, the surface of the sample may be subjected to a blackening treatment by carbon spray, gold deposition, or both of them as pretreatment. The thermal conductivity in the surface direction of the joint 30 was determined by cutting out 10 samples of 10 mm long × 1 mm wide × 1 mm thick from the joint 30 and measuring 10 samples so that the 1 mm wide portion was in the thickness direction in laser flash measurement. By arranging and bundling, a substantially rectangular parallelepiped sample of 10 mm long × 10 mm wide × 1 mm thick is produced. After that, the thermal diffusivity in the plane direction is obtained by performing the measurement in the same manner as the measurement method in the thickness direction. The measurement by the laser flash method can be performed at the measurement temperature at room temperature and in the air. As shown in the following equation (1), the thermal conductivity (W / (m · K)) is calculated by multiplying the specific heat and thermal diffusivity obtained above by the density of the sample. The density can be measured, for example, by the Archimedes method, and the specific heat can be measured by a known differential scanning calorimeter (DSC).
K = Cp × α × ρ (1)
(Where K is the thermal conductivity of the sample (W / (m · K)), Cp is the specific heat of the sample (J / (kg · K)), α is the thermal diffusivity of the sample (m ² / s), ρ represents the density (kg / m ³ ) of the sample.)

  In addition, other than the laser flash method, even when using a thermal diffusivity / thermal conductivity measuring device ai-Phase Mobile 1u (manufactured by Hitachi High-Tech Science) or a thermal conductivity measuring device TCi (manufactured by Rigaku Corporation) Good.

  The joint 30 may include, for example, a ceramic filler in addition to the resin material 321 and the fibers 322. Examples of the ceramic filler include alumina, silica, aluminum nitride, boron nitride, barium sulfate, and calcium carbonate.

  In the electrostatic chuck 100 of the present embodiment, the shear bonding strain of the joint 30 is 40% or more. In other words, the joint 30 has a certain degree of difficulty in shear fracture.

The shear bond strain of the joint 30 can be specified as follows. FIG. 5 is an explanatory diagram schematically showing a method for specifying the shear bond strain. First, as shown in columns A and B in FIG. 5, two substantially flat adherends 201 and 202 (for example, an aluminum plate) are sampled by a sample SA (initial thickness t) for which shear adhesion strain is specified. ) To join. For example, the size of the adherends 201 and 202 is 12.5 mm in width × 100 mm in length × 1 mm in thickness, and the joint portion is 12.5 mm in width × 12 in length at the end of each of the adherends 201 and 202. 0.5 mm. Next, as shown in column C of FIG. 5, the two adherends 201 and 202 are relatively moved so that a shear force acts on the sample SA. For example, using a known tensile tester (for example, Autograph AG-IS manufactured by Shimadzu Corporation), one of the adherends 201 is moved in one direction parallel to the bonding surface (for example, the upward direction in column C of FIG. 5). ) At a predetermined speed (for example, 2 mm / min) while measuring the load and the moving distance. The shear stress is calculated by dividing the load by the area of the joint before the test. The relative movement of the adherends 201 and 202 is continued until the sample SA breaks, and the distance ΔL when the shear stress is maximized is measured. Finally, as shown in the following equation (2), the distance ΔL is divided by the initial thickness t of the sample SA to calculate the shear strain (%) of the sample SA.
Shear adhesion strain (%) = (ΔL / t) × 100 (2)

  Moreover, when measuring the shear strain of the joining material already joined to the adherend, for example, it is performed as follows. First, the joint is cut out together with the adherend by a processing method such as laser cutting. The shape of the test piece to be cut out can be held by a jig of a tensile tester, and the joined adherends can be pulled in directions opposite to each other as shown in FIG. I just need. Before performing a tensile test, the area of the joint and the thickness of the joint in the cut test piece are measured. Thereafter, a tensile test is performed in the same manner as described above, and the shear strain (%) is calculated by dividing the distance ΔL when the shear stress is maximized by the initial thickness t of the joint.

  Further, in the electrostatic chuck 100 of the present embodiment, the Young's modulus of the bonding portion 30 is 10 MPa or less. That is, the joint 30 has a certain degree of flexibility.

  The Young's modulus of the joint portion 30 is specified using a known specifying method (for example, a method of performing a tensile test using a known tensile tester (for example, Autograph AG-IS manufactured by Shimadzu Corporation) as described below). be able to. The test piece can be manufactured by forming it into a sheet shape, heating and curing it according to the material, and then cutting it out to a predetermined size. The size of the test piece is, for example, 10 mm wide × 70 mm long. A portion having a length of 20 mm at both ends of the test piece is held by a jig, and a portion having an intermediate length of 30 mm is defined as a sample length. The moving distance and the load at that time are measured while pulling in the longitudinal direction at a speed of, for example, 50 mm / min until the test piece breaks. The tensile stress is calculated by dividing the load by the cross-sectional area of the test piece before the test, and the Young's modulus (elastic modulus) is calculated from the inclination near the origin of the tensile stress-strain diagram. The shape of the test piece may be a dumbbell shape specified in JIS K6251: 2010.

  Also, when measuring the Young's modulus of the bonding material that has been bonded to the adherend, the bonding material is cut off from the adherend using a knife or the like, and cut into, for example, the same width 10 mm × length 70 mm as described above and tested. A piece is prepared, and the Young's modulus can be calculated in the same manner as described above.

  In addition, in the electrostatic chuck 100 of the present embodiment, the rigidity of the joint 30 is 4 MPa or less. That is, the joint 30 has a certain degree of flexibility, particularly in the shear direction.

The rigidity of the joint 30 can be specified as follows. That is, similarly to the above-described method for specifying the shear bond strain, the two substantially flat adherends 201 and 202 (for example, an aluminum plate) are separated by the sample SA (initial thickness t) whose rigidity is to be specified. The two adherends 201 and 202 are moved relative to each other so that a shearing force acts on the sample SA (see column C in FIG. 5). For example, using a known tensile tester (for example, Autograph AG-IS manufactured by Shimadzu Corporation), one of the adherends 201 is moved in one direction parallel to the bonding surface (for example, the upward direction in column C of FIG. 5). ) At a predetermined speed (for example, 2 mm / min) while measuring the load and the moving distance ΔL ′. The shear stress is calculated by dividing the load by the area of the joint before the test. As shown in the following equation (3), the strain (%) is calculated by dividing the moving distance ΔL ′ by the initial thickness t of the sample SA. The rigidity is calculated from the inclination near the origin in the shear bond stress-strain diagram.
Strain (%) = (ΔL ′ / t) × 100 (3)

  Further, when measuring the rigidity of the bonding material already bonded to the adherend, for example, the measurement is performed as follows. First, the joint is cut out together with the adherend by a processing method such as laser cutting. The shape of the test piece to be cut out can be held by a jig of a tensile tester, and the joined adherends can be pulled in directions opposite to each other as shown in FIG. I just need. Before performing a tensile test, the area of the joint and the thickness of the joint in the cut test piece are measured. Thereafter, a tensile test is performed in the same manner as described above, and the rigidity is calculated from the inclination near the origin in the shear adhesive stress-strain diagram.

A-3. Manufacturing method of the electrostatic chuck 100:
The method for manufacturing the electrostatic chuck 100 of the present embodiment is, for example, as follows. First, the plate member 10 is manufactured by a known method. For example, a plurality of ceramic green sheets are prepared, and a predetermined processing is performed on a predetermined ceramic green sheet. Examples of the predetermined processing include printing of a metallizing paste for forming the chuck electrode 40, the heater electrode 50, and the like, drilling of holes for forming various vias, and filling of the metallizing paste. By laminating these ceramic green sheets, performing thermocompression bonding, and performing processing such as cutting, a laminated body of ceramic green sheets is produced. By firing the laminated body of the manufactured ceramic green sheets, the plate member 10 which is a fired ceramic body is manufactured. The base member 20 is manufactured by a known method.

  Further, a sheet-like adhesive for forming the joint 30 is prepared. Specifically, after the fiber sheet is impregnated with a liquid resin material, for example, after being placed in a film shape on a release sheet, it is semi-cured by a predetermined curing process to form the bonding portion 30. To prepare a sheet adhesive. In the sheet-like adhesive for forming the joint portion 30, the fibers 322 are partially entangled with each other, and a continuous space defined by the fibers 322 is filled with a resin material. A filler may be added to the liquid resin material in advance. Alternatively, the fiber-containing layer 32 is formed by applying a paste prepared by adding fibers and fillers to a liquid resin material, for example, in the form of a film on a release sheet, and semi-curing by a predetermined curing treatment. May be produced for the purpose. For example, by punching each sheet-like adhesive, the shape of each sheet-like adhesive is made into a desired shape (for example, a substantially annular shape and a substantially circular shape).

  Thereafter, the plate member 10 and the base member 20 are joined using the sheet adhesive for the joining portion 30. Specifically, a sheet-like adhesive for the joint 30 is applied to one surface (joint surface) of the plate-like member 10 and the base member 20 at a predetermined position (for example, a substantially annular sheet for the joint 30). The plate-like adhesive is disposed in the plane direction at the lower surface S2 of the plate-like member 10 or the center of the upper surface S3 of the base member 20), and the plate-like member 10 and the base member 20 are bonded via each sheet-like adhesive. The bonding portion 30 is formed by performing a curing process for curing the sheet-like adhesive. The electrostatic chuck 100 of the present embodiment is manufactured mainly through the above steps.

A-4. Effects of this embodiment:
As described above, the electrostatic chuck 100 of the present embodiment includes the plate member 10, the base member 20, and the joint 30. The plate-shaped member 10 has a suction surface S1 substantially orthogonal to the Z-axis direction and a lower surface S2 opposite to the suction surface S1. The base member 20 has an upper surface S3, and is arranged such that the upper surface S3 is located on the lower surface S2 side of the plate-shaped member 10. The base member 20 has a coolant channel 21. The joining portion 30 is disposed between the lower surface S2 of the plate member 10 and the upper surface S3 of the base member 20, and joins the plate member 10 and the base member 20. Further, in the electrostatic chuck 100 of the present embodiment, the bonding portion 30 includes the resin material 321 and the fibers 322 having a higher thermal conductivity than the thermal conductivity of the resin material 321.

  As described above, in the electrostatic chuck 100 of the present embodiment, since the bonding portion 30 contains a material having a higher thermal conductivity than the resin material 321 in the form of the fiber 322, the bonding portion 30 Has good thermal conductivity and sufficient flexibility. That is, since the fibers 322 can slide following the deformation of the resin material 321 at the joint 30, the joint 30 has sufficient flexibility as a whole. In this respect, it differs from the joint where the thermally conductive material is contained in the form of a woven fabric or mesh. Therefore, according to the electrostatic chuck 100 of the present embodiment, by ensuring good thermal conductivity in the Z-axis direction (that is, between the plate-shaped member 10 and the base member 20 via the joint portion 30), The responsiveness of the temperature of the suction surface S1 of the plate-shaped member 10 (that is, the temperature rising rate or the temperature falling rate) can be improved. Thereby, the rate of temperature rise and the rate of temperature decrease of the wafer W held on the suction surface S1 of the plate member 10 can be improved, and the processing efficiency of the wafer W can be increased. Further, according to the electrostatic chuck 100 of the present embodiment, the thermal expansion between the plate member 10 and the base member 20 while securing the bondability between the plate member 10 and the base member 20 by the bonding portion 30. By effectively relieving the stress caused by the difference (stress relaxation), the plate-shaped member can be prevented from being deformed due to thermal stress, and the occurrence of peeling between members and cracking of the member can be suppressed. can do.

  In the electrostatic chuck 100 of the present embodiment, the average orientation direction of the fibers 322 in the bonding portion 30 when viewed in the plane direction is substantially parallel to the plane direction orthogonal to the Z-axis direction. The heat transmitted to the fibers 322 spreads more in the longitudinal direction of the fibers 322. For this reason, if the longitudinal direction of the fiber 322 is substantially parallel to the plane direction in the joint section 30, in other words, if the average orientation direction of the fiber 322 in the plane direction is substantially parallel to the plane direction, the joint section 30 More effectively, the heat transmitted to the joint portion 30 is diffused in a joint surface with the lower surface S2 of the plate-shaped member 10, a joint surface with the upper surface S3 of the base member 20, and a surface direction inside the joint portion 30. Can be done. That is, the thermal conductivity in the surface direction of the joint 30 is improved. As a result, in the suction surface S1 of the plate-shaped member 10, an area which is likely to become a temperature singular point due to the influence of the base member 20 located via the joint portion 30, for example, is formed on the base member 20 when viewed in the Z-axis direction. It is possible to suppress a region overlapping with the refrigerant flow path 21 from becoming a low-temperature singular point. Therefore, according to the electrostatic chuck 100 of the present embodiment, it is possible to improve the uniformity of the temperature distribution of the suction surface S1 while ensuring the temperature responsiveness of the suction surface S1 of the plate-shaped member 10.

  Further, in the electrostatic chuck 100 of the present embodiment, the thermal conductivity in the surface direction of the joint 30 is higher than the thermal conductivity of the joint 30 in the Z-axis direction. For this reason, the heat transmitted to the joint portion 30 can be more effectively applied to the joint portion 30 at the joint surface with the lower surface S2 of the plate member 10, the joint surface with the upper surface S3 of the base member 20, and the joint portion 30. It can be diffused in the inner surface direction. That is, the thermal conductivity in the surface direction of the joint 30 is improved. As a result, in the suction surface S1 of the plate-shaped member 10, an area which is likely to become a temperature singular point due to the influence of the base member 20 located via the joint portion 30, for example, is formed on the base member 20 when viewed in the Z-axis direction. It is possible to suppress a region overlapping with the refrigerant flow path 21 from becoming a low-temperature singular point. Therefore, according to the electrostatic chuck 100 of the present embodiment, it is possible to improve the uniformity of the temperature distribution of the suction surface S1 while ensuring the temperature responsiveness of the suction surface S1 of the plate-shaped member 10.

  Further, in the electrostatic chuck 100 of the present embodiment, the shear bond strain of the joint 30 is 40% or more. In other words, the joint 30 has a certain degree of difficulty in shear fracture. As described above, such a high value of the shear bond strain is because the fibers 322 can slide following the deformation of the resin material 321 at the joint portion 30 and the joint portion 30 as a whole has sufficient flexibility. Can be realized. Therefore, in the electrostatic chuck 100 of the present embodiment, the presence of the fibers 322 in the bonding portion 30 ensures good thermal conductivity between the plate-like member 10 and the base member 20 while maintaining good thermal conductivity between the plate-like member 10 and the base member 20. The joint 30 is broken by stress due to a difference in thermal expansion between the base member 20 and peeling occurs between members (between the joint 30 and the plate member 10 or between the joint 30 and the base member 20). The occurrence can be suppressed. Therefore, according to the electrostatic chuck 100 of the present embodiment, the thermal conductivity (heat drawing) between the plate-shaped member 10 and the base member 20 due to the portion where the joint portion 30 is broken or the member is peeled off. Characteristic) is reduced, and in the adsorption surface S1 of the plate-shaped member 10, a region overlapping with the region where the fracture of the joint portion or the separation between the members has occurred in the Z-axis direction is suppressed from becoming a high temperature singular point. can do. Therefore, according to the electrostatic chuck 100 of the present embodiment, it is possible to improve the uniformity of the temperature distribution of the suction surface S1 while ensuring the temperature responsiveness of the suction surface S1 of the plate-shaped member 10.

  For example, the diameter of the plate member 10 is 360 mm, the thickness of the joint 30 is 1 mm, the plate member 10 is formed of alumina (coefficient of thermal expansion: 8.2 ppm / K), and the base member 20 is formed of aluminum. When the temperature at which the stress is zero is formed at 100 ° C. (curing temperature) and the temperature at the time of use is 150 ° C. for the plate member 10 and 20 ° C. for the base member 20, the bonding is performed. If the shear bond strain of the part 30 is 40% or more, the joint part 30 will not be broken.

  Further, in the electrostatic chuck 100 of the present embodiment, the Young's modulus of the bonding portion 30 is 10 MPa or less. That is, the joint 30 has a certain degree of flexibility. Such a low value of Young's modulus is realized because, as described above, each fiber 322 can slide following the deformation of the resin material 321 at the joint portion 30 and the joint portion 30 as a whole has sufficient flexibility. can do. Therefore, in the electrostatic chuck 100 of the present embodiment, the presence of the fibers 322 in the bonding portion 30 ensures good thermal conductivity between the plate-shaped member 10 and the base member 20 while maintaining good thermal conductivity between the plate-shaped member 10 and the base member 20. It is possible to suppress the occurrence of warpage due to stress due to a difference in thermal expansion between the base member 20 and the base member 20. Therefore, according to the electrostatic chuck 100 of the present embodiment, it is possible to prevent the processing speed (for example, the etching speed) for the wafer W from becoming non-uniform or the processing depth from being restricted due to the warpage. can do.

  In addition, in the electrostatic chuck 100 of the present embodiment, the rigidity of the joint 30 is 4 MPa or less. That is, the joint 30 has a certain degree of flexibility, particularly in the shear direction. Such a low rigidity value is realized because, as described above, each fiber 322 can slide following the deformation of the resin material 321 at the joint portion 30 and the joint portion 30 as a whole has sufficient flexibility. can do. Therefore, in the electrostatic chuck 100 of the present embodiment, the presence of the fibers 322 in the bonding portion 30 ensures good thermal conductivity between the plate-shaped member 10 and the base member 20 while maintaining good thermal conductivity between the plate-shaped member 10 and the base member 20. It is possible to suppress the occurrence of warpage due to stress due to a difference in thermal expansion between the base member 20 and the base member 20. Therefore, according to the electrostatic chuck 100 of the present embodiment, it is possible to prevent the processing speed (for example, the etching speed) for the wafer W from becoming non-uniform or the processing depth from being restricted due to the warpage. can do.

  Further, in the electrostatic chuck 100 of the present embodiment, the joint 30 includes the resin material 321. Therefore, according to the electrostatic chuck 100 of the present embodiment, the joining portion 30 effectively secures the joining property between the plate-shaped member 10 and the base member 20 while maintaining the joint between the plate-shaped member 10 and the base member 20. The stress caused by the difference in thermal expansion between the members can be effectively reduced, and the occurrence of peeling between members and cracking of the members can be effectively suppressed. Further, according to the electrostatic chuck 100 of the present embodiment, since the joint portion 30 includes the resin material 321, each of the first gas passage hole 131 and the pin insertion hole 140 formed in the joint portion 30 is formed. Airtightness between the hole and the inside of the vacuum chamber is ensured. For this reason, the helium gas in the first gas passage hole 131 and the air in the pin insertion hole 140 leak into the vacuum chamber in which the electrostatic chuck 100 is mounted, so that the degree of vacuum in the vacuum chamber is reduced. Reduction can be suppressed. In addition, since airtightness between the first gas passage hole 131 and the pin insertion hole 140 formed in the joint portion 30 is ensured, the helium gas in the first gas passage hole 131 and the pin Mixing with the atmosphere in the insertion hole 140 can be suppressed.

B. Second embodiment:
B-1. Configuration of electrostatic chuck 100a:
FIG. 6 is an explanatory diagram showing a detailed configuration near the joint 30a in the electrostatic chuck 100a of the second embodiment. FIG. 6 shows an XZ cross-sectional configuration of the electrostatic chuck 100a of the second embodiment corresponding to the XZ cross-sectional configuration of the electrostatic chuck 100 of the first embodiment shown in FIG. Hereinafter, among the configurations of the electrostatic chuck 100a of the second embodiment, the same components as those of the above-described electrostatic chuck 100 of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. .

  As shown in FIG. 6, the electrostatic chuck 100a according to the second embodiment includes a bonding portion 30a instead of the bonding portion 30 included in the electrostatic chuck 100 according to the first embodiment. The joint 30a is composed of a normal layer 31 and a fiber-containing layer 32, and differs from the joint 30 in this point. The normal layer 31 corresponds to the non-fiber-containing layer in the claims.

  The fiber-containing layer 32 of the joint 30a includes the resin material 321 and the fibers 322 as in the joint 30 of the electrostatic chuck 100 according to the first embodiment. In the electrostatic chuck 100a according to the second embodiment, the fiber-containing layer 32 includes a resin material 321 as a main component, similarly to the joint 30 of the electrostatic chuck 100 according to the first embodiment. The fiber-containing layer 32 may include, for example, a ceramic filler in addition to the resin material 321 and the fibers 322.

  On the other hand, the normal layer 31 of the joint 30a includes the resin material 321. In 100a of the second embodiment, the normal layer 31 includes a resin material 321 as a main component. As the resin material 321 included in the normal layer 31, various resin materials such as a silicone resin, an acrylic resin, and an epoxy resin can be used as in the case of the resin material 321 included in the fiber-containing layer 32. It is preferable to use an addition-curable silicone resin among the silicone resins. Note that the resin material 321 included in the normal layer 31 and the resin material 321 included in the fiber-containing layer 32 are preferably the same type of resin. This is because if the resin materials 321 are of the same type, the mutual wettability will be high and the adhesiveness will be good.

  The normal layer 31 of the joint 30a may include, for example, a ceramic filler in addition to the resin material 321. However, unlike the fiber-containing layer 32, the normal layer 31 does not include the fiber 322.

  As shown in FIG. 6, the joint 30 a is arranged such that the normal layer 31 is located on the base member 20 side and the fiber-containing layer 32 is located on the plate member 10 side. Specifically, the bonding portion 30a is bonded to the upper surface S3 of the base member 20 on the surface on the normal layer 31 side (the lower surface in the bonding portion 30a) in the Z-axis direction, and Is joined to the lower surface S2 of the plate-like member 10 on the surface (upper surface of the joint 30a). That is, the joint 30a has the fiber-containing layer 32 and the normal layer 31 arranged at a position different from the fiber-containing layer 32 in the Z-axis direction. Further, in the Z-axis direction, the fiber-containing layer 32 is disposed on the plate-like member 10 side in the joint 30a.

  In the joint 30a, the thickness T2 of the fiber-containing layer 32 in the Z-axis direction is larger than the thickness T1 of the normal layer 31. Preferably, the thickness T2 of the fiber-containing layer 32 is, for example, 0.1 mm or more and 1 mm or less, and the ratio of the thickness T2 of the fiber-containing layer 32 to the thickness T1 of the normal layer 31 is 2 or more. . More preferably, the thickness T2 of the fiber-containing layer 32 is 0.3 mm or more and 0.8 mm or less, and the ratio of the thickness T2 of the fiber-containing layer 32 to the thickness T1 of the normal layer 31 is 3 or more, 10 or less. The method for specifying the normal layer 31 and the fiber-containing layer 32 in the joint 30a and the method for measuring the thicknesses T1 and T2 of the layers 31 and 32 will be described later in detail.

B-2. Method for specifying the internal configuration at the joint 30a:
The internal configuration of the joint 30a in the electrostatic chuck 100a, that is, the method for specifying the normal layer 31 and the fiber-containing layer 32 in the joint 30a is as follows. First, an XZ section parallel to the up-down direction in the joining portion 30a is arbitrarily set, and an SEM image (for example, 300 times) of the FE-SEM (acceleration voltage 1.5 kV) is obtained in the XZ section.

  The boundary between the normal layer 31 and the fiber-containing layer 32 can be specified as follows. When the resin materials 321 contained in the normal layer 31 and the fiber-containing layer 32 are of different types, the boundary between the normal layer 31 and the fiber-containing layer 32 is usually clearly identified by observation with an FE-SEM. be able to. If the resin material 321 contained in the normal layer 31 and the fiber-containing layer 32 is of the same kind and the boundary between the normal layer 31 and the fiber-containing layer 32 cannot be clearly specified, the resin material 321 is contained in the fiber-containing layer 32. A virtual line connecting the lower ends of the fibers 322 to be formed can be specified as a boundary between the normal layer 31 and the fiber-containing layer 32. Specifically, it can be obtained by the following method. First, after the electrostatic chuck 100a is cut and the cut surface is polished, the processed surface is imaged with a FE-SEM (acceleration voltage 1.5 kV) at a magnification of 100 times. At this time, the imaging is performed so that the plate-shaped member 10, the base member 20, and the joint 30a fall within the obtained SEM image, and the thickness direction of the joint 30a matches the Z-axis direction in the SEM image. In the obtained SEM image, a plurality of lines orthogonal to the Z-axis direction are drawn at predetermined intervals (for example, at 1 μm intervals) from above. Among the lines, the first line which is the line on which the plate-shaped member 10 does not overlap and which is located at the uppermost direction is specified. Next, among the lines, a second line which is the line on which the base member 20 does not overlap and which is located at the lowest position is specified. Next, in the Z-axis direction, among the lines located between the first line and the second line, the third line, which is the line on which the fiber 322 does not overlap on the line, is located at the uppermost position. Identify the line. In the Z-axis direction, the distance between the first line and the third line is specified as the thickness of the fiber-containing layer 32, and the distance between the third line and the second line is usually determined. The thickness of the layer 31 can be specified. The thickness of each of the layers 31 and 32 can be calculated by comparison with the scale in the SEM image.

B-3. Manufacturing method of electrostatic chuck 100a:
The method for manufacturing the electrostatic chuck 100a of the second embodiment is, for example, as follows. The plate member 10 and the base member 20 can be manufactured by the same method as the plate member 10 and the base member 20 in the electrostatic chuck 100 according to the first embodiment.

  Further, each layer (the normal layer 31 and the fiber-containing layer 32) of the joint 30a can be manufactured by the following method. First, a sheet adhesive for forming the normal layer 31 and the fiber-containing layer 32 is prepared. Specifically, a paste prepared by adding a filler as necessary to a liquid resin material, for example, is applied in the form of a film on a release sheet, and then semi-cured by a predetermined curing treatment to form a normal layer. A sheet-like adhesive for forming 31 is produced. The sheet adhesive for forming the fiber-containing layer 32 can be manufactured by the same method as the sheet adhesive for forming the joint 30 in the electrostatic chuck 100 according to the first embodiment. For example, by punching each sheet-like adhesive, the shape of each sheet-like adhesive is made into a desired shape (for example, a substantially annular shape and a substantially circular shape).

  Thereafter, the plate-shaped member 10 and the base member 20 are joined using the sheet-shaped adhesive for the normal layer 31 and the sheet-shaped adhesive for the fiber-containing layer 32. Specifically, the sheet-like adhesive for the fiber-containing layer 32 is applied to the surface (joining surface) of the plate-like member 10 at a predetermined position (for example, the sheet-like adhesive for the substantially annular fiber-containing layer 32 is (The center of the lower surface S2 of the shaped member 10) in the plane direction. On the other hand, on the surface (joining surface) of the base member 20, the sheet-like adhesive for the normal layer 31 is applied at a predetermined position (for example, the substantially annular sheet-like adhesive for the normal layer 31 is applied to the upper surface S3 of the base member 20). (Center) in the plane direction. Thereby, the plate member 10 and the base member 20 are bonded together via the respective sheet-like adhesives, and a curing process for curing the respective sheet-like adhesives is performed, so that the bonding portion 30a (the normal layer 31 and the fiber-containing layer 32) is formed. The electrostatic chuck 100a of the second embodiment is manufactured mainly through the above steps.

B-4. Effects of this embodiment:
As described above, in the electrostatic chuck 100a according to the second embodiment, the bonding portion 30a is disposed at a position different from the fiber-containing layer 32 in the Z-axis direction with the fiber-containing layer 32 containing the fiber 322. , A normal layer 31 containing no fibers 322. Since the normal layer 31 does not contain the fiber 322, it has higher flexibility than the fiber-containing layer 32. As described above, in the electrostatic chuck 100a, the joint 30a has the fiber-containing layer 32 having good thermal conductivity and the normal layer 31 having higher flexibility. Therefore, according to the electrostatic chuck 100a of the second embodiment, the temperature responsiveness of the suction surface S1 of the plate-shaped member 10 is ensured, and the bonding property between the plate-shaped member 10 and the base member 20 is determined by the bonding portion 30a. And the stress relaxation between the plate member 10 and the base member 20 can be ensured.

  In the electrostatic chuck 100a of the second embodiment, the thickness T2 of the fiber-containing layer 32 is larger than the thickness T1 of the normal layer 31 in the Z-axis direction. For this reason, it is possible to suppress a decrease in the thermal conductivity at the joint 30a as compared with a configuration in which the entire joint 30a is formed of the normal layer 31 or a configuration in which the normal layer 31 is thicker than the fiber-containing layer 32. . Further, in the electrostatic chuck 100a of the second embodiment, the thermal conductivity in the plane direction can be made higher than the thermal conductivity in the Z-axis direction in the entire joint 30a. Therefore, according to the electrostatic chuck 100a of the second embodiment, while the stress relaxation between the plate member 10 and the base member 20 is ensured, the temperature responsiveness of the suction surface S1 of the plate member 10 (that is, the temperature response) , And the uniformity of the temperature distribution on the suction surface S1 of the plate-shaped member 10 can be improved while suppressing a decrease in the temperature rising rate and the temperature decreasing rate.

  Further, the electrostatic chuck 100a of the second embodiment further includes a heater electrode 50 which is a resistance heating element disposed on the plate member 10, and the fiber-containing layer 32 Is disposed on the side of the plate-shaped member 10. The portion of the joining portion 30a that constitutes the plate member 10 including the heater electrode 50 is a portion that may be exposed to high-temperature heat. This is because the heater electrode 50 and the wafer W are heated by heat or the like generated during processing. Since the fiber-containing layer 32 contains the fiber 322, it has good heat resistance. This is because, in addition to the fiber 322 itself having high heat resistance, since the fiber-containing layer 32 contains the fiber 322, oxygen which may be a factor of deteriorating the resin material 321 contained in the fiber-containing layer 32, This is because it becomes difficult to pass through the fiber-containing layer 32. In addition, radicals derived from oxygen deteriorate the resin material 321, but the fibers 322 included in the fiber-containing layer 32 capture and inactivate the radicals, so that deterioration of the resin material 321 can be suppressed. For this reason, it is possible to suppress the occurrence of peeling between the members due to the decomposition of the resin contained in the joint portion 30, and thus to suppress the nonuniform temperature distribution of the adsorption surface S <b> 1 of the plate-shaped member 10. can do.

C. Modification:
The technology disclosed in the present specification is not limited to the above-described embodiment, and can be modified into various forms without departing from the gist thereof. For example, the following modifications are also possible.

  The configuration of the electrostatic chuck 100 in the above embodiment is merely an example, and can be variously modified. More specifically, in the above-described embodiment, the average orientation direction of the fibers 322 in the planar direction is substantially parallel to the planar direction in the joint portion 30, but the average orientation direction of the fibers 322 in the planar direction is not necessarily the planar direction. Need not be substantially parallel to.

  Further, in the above-described embodiment, the fiber-containing layer 32 of the bonding portion 30 and the bonding portion 30a, that is, the portion containing the fiber 322 is disposed over the entire surface in the plane direction. However, the bonding portion 30 and / or the bonding portion 30a The fiber-containing layer 32 may be disposed only in a part of the surface direction, or may be disposed in a plurality of parts in the surface direction.

  In the second embodiment, the fiber-containing layer 32 is disposed over the normal layer 31 over the entire surface in the joint portion 30a, but the fiber-containing layer 32 is disposed under the normal layer 31. Or the fiber-containing layer 32 may be arranged on both the upper side and the lower side of the normal layer 31.

  In the above embodiment, the shear bond strain of the joint 30 is 40% or more, the Young's modulus of the joint 30 is 10 MPa or less, and the rigidity of the joint 30 is 4 MPa or less. Is a preferable range, and it is not always necessary to satisfy the numerical ranges of these physical property values.

  In the above embodiment, the heater electrode 50 is disposed inside the plate member 10, but the heater electrode 50 does not necessarily need to be disposed inside the plate member 10, and the heater electrode 50 is disposed on the surface of the plate member 10. The electrode 50 may be provided. Further, in the above-described embodiment, the refrigerant flow path 21 is formed in the base member 20. However, the refrigerant flow path 21 does not necessarily need to be formed in the base member 20. A cooling mechanism may be provided.

  In the above-described embodiment, a monopolar system in which one chuck electrode 40 is provided inside the plate member 10 is adopted. However, a bipolar system in which a pair of chuck electrodes 40 are provided inside the plate member 10 is used. May be employed.

  The material for forming each member in the electrostatic chuck 100 of the above embodiment is merely an example, and can be arbitrarily changed. For example, in the above embodiment, the plate member 10 is formed of ceramics, but the plate member 10 may be formed of a material other than ceramics (for example, a resin material). In the above embodiment, the resin material 321 included in the normal layer 31 of the joint 30 and the resin material 321 included in the fiber-containing layer 32 may be the same or different. However, it is preferable that the resin materials 321 be of the same kind, since the mutual wettability is high and the adhesiveness is good. Further, in the above-described embodiment, the normal layer 31 and the fiber-containing layer 32 of the joint 30 include the resin material 321 as a main component, but the normal layer 31 and / or the fiber-containing layer 32 include the resin material 321 as a subcomponent. It may be included.

  The method of manufacturing the electrostatic chuck 100 according to the above-described embodiment is merely an example, and can be variously modified. For example, in the second embodiment, a sheet-like adhesive for forming the normal layer 31 of the joint 30 and a sheet-like adhesive for forming the fiber-containing layer 32 are prepared, and the normal layer 31 is formed on the base member 20. After arranging the fiber-containing layer 32 on the plate member 10, the plate member 10 and the base member 20 are bonded to each other with each sheet adhesive. After forming a sheet-like adhesive for forming the sheet-like adhesive and a sheet-like adhesive for forming the fiber-containing layer 32, these sheet-like adhesives are laminated to produce an adhesive laminate, and the produced laminate is produced. The plate member 10 and the base member 20 are arranged such that the surface on the normal layer 31 side of the adhesive laminate is located on the base member 20 side and the surface on the fiber-containing layer 32 side is located on the plate member 10 side. May be attached via an adhesive laminate. .

  The present invention is not limited to the electrostatic chuck 100 that holds a wafer W using electrostatic attraction, but includes a plate-shaped member, a base member, and a joint, and holds an object on the surface of the plate-shaped member. The present invention can be similarly applied to other holding devices (for example, a vacuum chuck or the like).

10: Plate member 16: Hole 20: Base member 21: Refrigerant channel 25: Hole 26: Hole 30: Joint 30a: Joint 31: Normal layer 32: Fiber-containing layer 35: Hole 36: Hole 40: Chuck electrode 50: heater electrode 100: electrostatic chuck 100a: electrostatic chuck 131: first gas passage hole 132: second gas passage hole 133: lateral passage 134: enlarged diameter portion 140: pin insertion hole 160: filling member (Breathable plugs) 201, 202: adherend 321: resin material 322: fiber Lf: length S1: adsorption surface S2: lower surface S3: upper surface S4: lower surface SA: sample T1, T2: thickness VL1: first Virtual straight line VL2: Second virtual straight line W: Semiconductor wafer

Claims (10)

A plate-shaped member having a first surface substantially orthogonal to a first direction and a second surface opposite to the first surface;
A base member having a third surface, the third surface being disposed so as to be located on the second surface side of the plate-like member, and having a cooling mechanism;
A joint disposed between the second surface of the plate member and the third surface of the base member to join the plate member and the base member;
A holding device for holding an object on the first surface of the plate-shaped member,
The bonding portion includes a bonding material, and a fiber having a higher thermal conductivity than the thermal conductivity of the bonding material.
A holding device characterized by the above-mentioned. The holding device according to claim 1,
In the bonding portion, an average orientation direction of the fibers is substantially parallel to a second direction orthogonal to the first direction.
A holding device characterized by the above-mentioned. The holding device according to claim 2,
The thermal conductivity of the joint in the second direction is higher than the thermal conductivity of the joint in the first direction,
A holding device characterized by the above-mentioned. In the holding device according to any one of claims 1 to 3,
The bonding portion has a fiber-containing layer containing the fiber, and a fiber-free layer that does not contain the fiber, which is disposed at a position different from the fiber-containing layer in the first direction.
A holding device characterized by the above-mentioned. The holding device according to claim 4,
In the first direction, the thickness of the fiber-containing layer is greater than the thickness of the non-fiber-containing layer,
A holding device, characterized in that: The holding device according to claim 4 or 5, further comprising:
A heater electrode that is a resistance heating element disposed on the plate-shaped member,
In the first direction, the fiber-containing layer is disposed on the plate-like member side of the joint portion.
A holding device characterized by the above-mentioned. In the holding device according to any one of claims 1 to 6,
The shear bond strain of the joint is 40% or more;
A holding device characterized by the above-mentioned. The holding device according to any one of claims 1 to 7,
Young's modulus of the joint is 10 MPa or less,
A holding device characterized by the above-mentioned. The holding device according to any one of claims 1 to 8,
The rigidity of the joint is 4 MPa or less;
A holding device characterized by the above-mentioned. The holding device according to any one of claims 1 to 9,
The joint includes a resin material,
A holding device, characterized in that:

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