JP2020009932A - Retainer - Google Patents

Abstract

To control temperature distribution on the first surface of a plate-like member.SOLUTION: A retainer includes a plate-like member having a substantially planar first surface perpendicular to a first direction, multiple external terminals provided on the front side of the plate-like member, and a heater electrode placed in the plate-like member, and electrically connected with at least a pair of external terminals out of the multiple external terminals. In a retainer for retaining an object on the first surface of the plate-like member, the plate-like member includes a dummy via which is not electrically connected with any of the multiple external terminals, formed of a material having heat conductivity higher than that of the formation material of the plate-like member, placed between the first surface and the heater electrode in the first direction, and extending in a direction substantially parallel with the first direction.SELECTED DRAWING: Figure 5

Description

  The technology disclosed in the present specification relates to a holding device.

  For example, an electrostatic chuck is used as a holding device for holding a wafer when manufacturing a semiconductor. The electrostatic chuck is provided inside a ceramic member having a substantially planar surface (hereinafter, referred to as “adsorption surface”) substantially perpendicular to a predetermined direction (hereinafter, referred to as “first direction”). And chucking the wafer on the suction surface of the ceramic member using electrostatic attraction generated by applying a voltage to the chuck electrode. (See Patent Documents 1 and 2 below).

  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.

International Publication No. WO 2014/156519 JP-A-2002-222851

  In the electrostatic chuck, for example, a low temperature singularity may exist due to the internal structure of the ceramic member. Therefore, in the conventional electrostatic chuck, there is room for improvement in controllability of the temperature distribution on the suction surface of the ceramic member (and, consequently, controllability of the temperature distribution of the wafer).

  Such a problem is not limited to an electrostatic chuck that holds a wafer using electrostatic attraction, but is a common problem in general holding devices that hold an object on the surface of a ceramic member having a heater electrode.

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

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

(1) A holding device disclosed in the present specification includes a plate-like member having a substantially planar first surface substantially perpendicular to a first direction, and a plurality of plate-like members provided on the surface side of the plate-like member. An external terminal, and a heater electrode disposed inside the plate-shaped member and electrically connected to at least a pair of external terminals of the plurality of external terminals. In the holding device for holding the object on the surface of the, the plate-shaped member is electrically connected to only one of the plurality of external terminals, or to any of the plurality of external terminals A dummy via that is not electrically connected, and is formed of a material having a higher thermal conductivity than a material for forming the plate-like member, and is disposed between the first surface and the heater electrode in the first direction. And extends in a direction substantially parallel to the first direction. It is equipped with a dummy via that. In the present holding device, the plate member has a dummy via. The dummy via is formed of a material having a higher thermal conductivity than the material of the plate member. Therefore, between the first surface and the heater electrode, the portion where the dummy via is arranged has higher heat conductivity than the portion where the dummy via is not arranged. Further, the dummy via is electrically connected to only one of the plurality of external terminals, or is not electrically connected to any of the plurality of external terminals. That is, even during the operation of the holding device, no current flows through the dummy via, so that the dummy via does not generate heat. Therefore, the dummy via does not become a high temperature singularity due to the heat generated by the dummy via itself. Further, since the dummy vias extend in a direction substantially parallel to the first direction, the heat storage effect per unit area in the first direction can be compared with, for example, a flat dummy portion arranged on a virtual plane. Is high. Thus, according to the present holding device, by arranging the dummy vias, the temperature difference between the low-temperature portion having a relatively low temperature on the first surface and the surrounding portion of the low-temperature portion is reduced, so that the low-temperature portion is formed. The occurrence of a temperature singularity can be suppressed, and the temperature distribution on the first surface of the plate member can be controlled. Further, for example, as compared with a configuration in which a dummy via is arranged between the heater electrode of the plate-shaped member and the surface opposite to the first surface, the dummy via is formed between the heater electrode of the plate-shaped member and the surface opposite to the first surface. Interference with the internal structure disposed between them can be suppressed.

(2) In the holding device, the plate-shaped member is further electrically connected to only one of the plurality of external terminals, or electrically connected to any of the plurality of external terminals. A dummy portion that is not connected, and is formed of a material having a higher thermal conductivity than the material for forming the plate-shaped member, and has an area in a first direction as viewed in the first direction of the dummy via. A configuration may be provided in which a dummy portion larger than the area and electrically connected to the dummy via is provided. In the present holding device, since the dummy portion is electrically connected to the dummy via, the heat transmitted to the dummy via spreads in a direction parallel to the first surface by the dummy portion. Therefore, according to the present holding device, since the heat accumulated in the dummy via is diffused as compared with the configuration without the dummy portion, the occurrence of the temperature singular point on the first surface is more effectively suppressed. Thus, the temperature distribution on the first surface of the plate member can be controlled.

(3) In the holding device, a gas flow path is formed in the plate-shaped member, and at least a part of the dummy via is configured to be connected to a gas inlet in the gas flow path in the first direction. It is good also as a structure which overlaps. In the present holding device, the dummy via is arranged at a position overlapping the gas inlet having a relatively low temperature in the gas flow path when viewed in the vertical direction. For this reason, according to the present holding device, it is possible to suppress the occurrence of a low-temperature singularity caused by the presence of the gas flow inlet, and to control the temperature distribution on the first surface of the plate-shaped member. Can be.

(4) In the holding device, the plate-shaped member has a second surface disposed on a side opposite to the first surface in the first direction, and the holding device further includes a third surface. A base member having a surface, the third surface being disposed so as to face the second surface of the plate-like member, and a base member formed of a material having a higher thermal conductivity than a material for forming the plate-like member; And a joint disposed between the second surface of the plate member and the third surface of the base member, and joining the plate member and the base member. . For example, due to the structure of the base member or the like, a difference occurs in the heat absorbing effect from the ceramic member to the base member between the specific position on the third surface of the base member and another position, so that so-called uneven heat absorption occurs. Sometimes. Even when such heat absorption unevenness occurs in the base member, in the present holding device, for example, a dummy via is arranged at a position corresponding to a position where the heat absorption effect of the base member is relatively large, so that a low temperature singular point is obtained. Can be suppressed, and the temperature distribution on the first surface of the plate member can be controlled.

(5) In the holding device, a coolant flow path is formed in the base member, and at least a part of the dummy via overlaps a coolant inlet in the coolant flow path in the first direction. May be adopted. In the present holding device, the dummy via is arranged at a position overlapping with the inlet of the refrigerant having a relatively low temperature in the refrigerant flow path when viewed in the vertical direction. For this reason, according to the present holding device, it is possible to suppress the occurrence of a low-temperature singularity due to the presence of the inflow port of the coolant channel, and to control the temperature distribution on the first surface of the plate-shaped member. Can be.

  The technology disclosed in the present specification can be realized in various forms, for example, a heater device such as an electrostatic chuck, a CVD heater, a vacuum chuck, and other ceramic members provided with heater electrodes. , And a method of manufacturing them.

FIG. 1 is a perspective view schematically illustrating an external configuration of an electrostatic chuck 10 according to an embodiment. FIG. 2 is an explanatory diagram schematically illustrating an XZ cross-sectional configuration of the electrostatic chuck 10 according to the embodiment. FIG. 3 is an explanatory diagram schematically showing an XY cross-sectional configuration of the electrostatic chuck according to the embodiment. FIG. 3 is an explanatory diagram schematically showing an XY cross-sectional configuration of the electrostatic chuck according to the embodiment. FIG. 2 is an explanatory diagram schematically showing a configuration of an electrostatic chuck 10. 4 is a flowchart illustrating a first method for manufacturing the electrostatic chuck 10.

A. Embodiment:
A-1. Configuration of electrostatic chuck 10:
FIG. 1 is a perspective view schematically illustrating an external configuration of the electrostatic chuck 10 according to the present embodiment, and FIG. 2 is an explanatory diagram schematically illustrating an XZ cross-sectional configuration of the electrostatic chuck 10 according to the present embodiment. 3 and 4 are explanatory diagrams schematically showing the XY cross-sectional configuration of the electrostatic chuck 10 in the present embodiment. FIG. 2 shows an XZ cross-sectional configuration of the electrostatic chuck 10 at the position II-II in FIGS. 3 and 4. FIG. 3 shows the electrostatic chuck 10 at the position III-III in FIG. An XY cross-sectional configuration is shown, and FIG. 4 shows an XY cross-sectional configuration of the electrostatic chuck 10 at a position IV-IV 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 10 is actually installed in a direction different from such a direction. May be done.

  The electrostatic chuck 10 is a device that attracts and holds an object (for example, a 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 10 includes a ceramic member 100 and a base member 200 arranged side by side in a predetermined arrangement direction (a vertical direction (Z-axis direction) in the present embodiment). The ceramic member 100 and the base member 200 are arranged such that the lower surface S2 of the ceramic member 100 and the upper surface S3 of the base member 200 face in the arrangement direction.

  The ceramic member 100 is, for example, a plate member having a circular flat surface, and is formed of ceramics (for example, alumina, aluminum nitride, or the like). The diameter of the ceramic member 100 is, for example, about 50 mm to 500 mm (normally, about 200 mm to 450 mm), and the thickness of the ceramic member 100 is, for example, about 1 mm to 10 mm.

  Inside the ceramic member 100, a pair of chuck electrodes 400 formed of a conductive material (for example, tungsten or molybdenum) are provided (only one chuck electrode 400 is shown in FIG. 2). When a voltage is applied to the pair of chuck electrodes 400 from a power supply (not shown), an electrostatic attraction is generated, and the wafer W is placed on the surface of the ceramic member 100 opposite to the lower surface S2 (hereinafter, referred to as an electrostatic attraction). (Referred to as “adsorption surface S1”). The suction surface S1 of the ceramic member 100 is a substantially planar surface that is substantially perpendicular to the above-described arrangement direction (Z-axis direction). In this specification, a direction perpendicular to the Z-axis (that is, a direction parallel to the suction surface S1) is referred to as a “plane direction”.

  The base member 200 is, for example, a circular plate-shaped member having the same diameter as the ceramic member 100 or having a larger diameter than the ceramic member 100, and is formed of, for example, a metal (aluminum, aluminum alloy, or the like). The diameter of the base member 200 is, for example, about 220 mm to 550 mm (normally, 220 mm to 470 mm), and the thickness of the base member 200 is, for example, about 20 mm to 40 mm.

  A coolant channel 210 is formed inside the base member 200 (see FIG. 2). On the lower surface S4 of the base member 200, a coolant supply hole 226 for supplying the coolant CF from the outside into the coolant channel 210 and a coolant discharge hole 228 for discharging the coolant CF from the inside of the coolant channel 210 to the outside are formed. I have. When a coolant (for example, a fluorine-based inert liquid or water) flows through the coolant channel 210, the base member 200 is cooled and heat is transferred between the base member 200 and the ceramic member 100 via the adhesive layer 300. The ceramic member 100 is cooled, and the wafer W held on the suction surface S1 of the ceramic member 100 is cooled. Thereby, the temperature control of the wafer W is realized.

  The ceramic member 100 and the base member 200 are joined to each other by an adhesive layer 300 disposed between the lower surface S2 of the ceramic member 100 and the upper surface S3 of the base member 200. The adhesive layer 300 is made of, for example, an adhesive such as a silicone resin, an acrylic resin, or an epoxy resin. The thickness of the adhesive layer 300 is, for example, about 0.1 mm to 1 mm.

  As shown in FIGS. 2 and 4, inside the ceramic member 100, a heater electrode 500 formed of a resistance heating element formed of a conductive material (for example, tungsten or molybdenum) is provided. When a voltage is applied to the heater electrode 500 from a power supply (not shown), the heater electrode 500 generates heat, thereby heating the ceramic member 100 and the wafer W held on the suction surface S1 of the ceramic member 100. Thereby, the temperature control of the wafer W is realized.

  In the present embodiment, the heater electrode 500 includes a first heater 500L and a second heater 500R in order to accurately control the temperature of the suction surface S1 of the ceramic member 100. The first heater 500L and the second heater 500R are independently arranged on one virtual plane (for example, the XY plane in FIG. 4) substantially perpendicular to the Z-axis direction. In other words, each of the heaters 500L and 500R is included in each segment (region) when at least a part of the ceramic member 100 is virtually divided into a plurality of segments (regions) arranged in a direction substantially perpendicular to the Z-axis direction. It is a heating resistor arranged. As a setting mode of the segment, a mode is used in which the whole or a part of the ceramic member 100 is divided into a plurality of segments arranged in a circumferential direction around the center point of the suction surface S1. Each of the heaters 500L and 500R includes a linear heater line portion 506 and a pair of heater pad portions 508 joined to both ends of the heater line portion 506 when viewed in the vertical direction (Z direction).

  In the electrostatic chuck 10, a plurality of terminal holes (only one terminal hole 224 is shown) extending from the lower surface S4 of the base member 200 to the lower surface S2 of the ceramic member 100 are formed. Accommodates an external terminal (only the common external terminal 530 accommodated in the terminal hole 224 is shown). At least the terminal hole 224 and the common external terminal 530 are arranged at the center of the suction surface S1 of the ceramic member 100 when viewed in the vertical direction (Z-axis direction). One heater pad portion 508 of each of the two heaters 500L and 500R is electrically connected to a different individual external terminal (not shown) via a via, an electrode pad (both not shown), or the like. On the other hand, the other heater pad portion 508 of each of the two heaters 500L and 500R is electrically connected to the common external terminal 530 via the energizing via 510 and the electrode pad 520. Since different power sources are connected between each of the two individual external terminals and the common external terminal, different voltages can be applied to each of the two heaters 500L and 500R. According to such a configuration, the temperature can be controlled for each segment by individually controlling the heaters 500L and 500R arranged in each segment, and as a result, the temperature control of the suction surface S1 of the ceramic member 100 can be performed. Can be performed with high accuracy.

A-2. Configuration for supplying gas:
In addition, the electrostatic chuck 10 increases the heat transfer between the ceramic member 100 and the wafer W to further increase the uniformity of the temperature distribution of the wafer W, so that the suction surface S1 of the ceramic member 100 and the surface of the wafer W There is provided a configuration for supplying gas to a space existing between them. In the present embodiment, helium gas (He gas) is used as such a gas. Hereinafter, a configuration for supplying a helium gas will be described with reference to FIGS. 1 to 3.

A-2-1. Configuration for supplying gas in base member 200:
As shown in FIG. 2, a gas source connection hole 221 connected to a helium gas source (not shown) is formed on the lower surface S4 of the base member 200, and a gas supply hole 222 is formed on the upper surface S3 of the base member 200. It is open. Inside the base member 200, a gas supply channel 220 that connects the gas source connection hole 221 and the gas supply hole 222 is formed.

A-2-2. Configuration for supplying gas in adhesive layer 300:
As shown in FIG. 2, a through hole 310 is formed in the adhesive layer 300 so as to communicate with the gas supply hole 222 formed in the base member 200 and penetrate the adhesive layer 300 in the thickness direction (vertical direction). Have been.

A-2-3. Configuration for supplying gas in ceramic member 100:
Further, as shown in FIGS. 1 and 2, eight gas ejection holes 102 are opened on the adsorption surface S1 of the ceramic member 100. Further, inside the ceramic member 100, a gas ejection flow path 110 connecting the lower surface S <b> 2 of the ceramic member 100 and the gas ejection hole 102 opened on the adsorption surface S <b> 1 of the ceramic member 100 is formed. As shown in FIGS. 2 and 3, the gas ejection channel 110 has a first vertical channel 111 extending upward from the lower surface S <b> 2, and a lateral flow that communicates with the first vertical channel 111 and extends annularly in the plane direction. It comprises a channel 114 and a second vertical channel 112 extending upward from the horizontal channel 114 and communicating with the gas ejection holes 102.

  In the electrostatic chuck 10 of the present embodiment, there are two helium gas supply paths. That is, as shown in FIG. 3, two lateral channels 114 are formed inside the ceramic member 100. As shown in FIGS. 2 and 3, one of the two lateral channels 114 closer to the center of the ceramic member 100 is connected to the through hole 310 of the adhesive layer 300 via the first vertical channel 111. And, through the second vertical flow path 112, with the four gas ejection holes 102 close to the center of the ceramic member 100 among the eight gas ejection holes 102 opening to the adsorption surface S1. ing. Further, of the two horizontal channels 114, the horizontal channel 114 farther from the center of the ceramic member 100 communicates with the through hole (not shown) of the adhesive layer 300 via the first vertical channel 111, and The second vertical flow path 112 communicates with the four gas ejection holes 102 far from the center of the ceramic member 100 among the eight gas ejection holes 102 opening to the adsorption surface S1. In the present embodiment, the first vertical flow path 111 and the second vertical flow path 112 communicating with the horizontal flow path 114 far from the center of the ceramic member 100 are located at different positions in the vertical direction. (See FIGS. 3 and 5).

  As shown in FIGS. 2 and 3, helium gas supplied from a helium gas source (not shown) flows into the gas supply channel 220 inside the base member 200 from the gas source connection hole 221. The helium gas flowing into the gas supply channel 220 flows into the through hole 310 of the adhesive layer 300 from the gas supply channel 220 via the gas supply hole 222. The helium gas that has flowed into the through hole 310 flows into the first vertical flow path 111 that forms the gas ejection flow path 110 inside the ceramic member 100, and passes through the horizontal flow path 114 and the second vertical flow path 112. The gas is ejected from each gas ejection hole 102 formed on the suction surface S1. Thus, the helium gas is supplied to the space existing between the suction surface S1 and the surface of the wafer W.

A-3. Configuration for controlling temperature distribution on adsorption surface S1 of ceramic member 100:
FIG. 5 is an explanatory diagram schematically showing the configuration of the electrostatic chuck 10. FIG. 5 shows an XY plane configuration when the electrostatic chuck 10 is viewed from above, and also shows an enlarged configuration of four portions X1 to X4 in the ceramic member 100.

  Inside the ceramic member 100, a dummy via 600 (610, 620, 630, 640) and a dummy portion 700 are provided. The dummy via 600 and the dummy section 700 are not electrically connected to any external terminals. Therefore, during the operation of the electrostatic chuck 10, no voltage is applied to the dummy via 600 and the dummy portion 700, and no current flows, so that the dummy via 600 does not generate heat. Therefore, neither the dummy via 600 nor the dummy section 700 becomes a high temperature singular point due to its own heat generation. The dummy via 600 and the dummy portion 700 are formed of a material having a higher thermal conductivity than the material for forming the ceramic member 100 (for example, a ceramic mainly composed of alumina). In the present embodiment, the dummy via 600 and the dummy portion 700 are formed of the same material as the material of the heater electrode 50 (for example, a conductive material containing tungsten).

  As shown in FIG. 2, the shape of the dummy via 600 is a linear shape extending in a direction substantially parallel to the vertical direction (Z-axis direction). Specifically, when viewed in the vertical direction, the maximum width of the dummy via 600 is smaller than the width dimension of the heater electrode 500 (the dimension in the direction perpendicular to the longitudinal direction of the heater electrode 500). The vertical length of the dummy via 600 is larger than the vertical length (that is, the thickness dimension) of the heater electrode 500. In the present embodiment, the dummy via 600 has a configuration similar to a conductive via (both the conducting via 510 and the like) whose both ends are electrically connected to external terminals, and is not electrically connected to any external terminals. This is different from the via for conduction. Further, the whole of the dummy via 600 is disposed between the suction surface S1 of the ceramic member 100 and the heater electrode 500 in the vertical direction. Each arrangement of the dummy vias 600 will be described later in detail.

  As shown in FIG. 2, the shape of the dummy portion 700 is a substantially flat shape that extends in the surface direction. Specifically, the area of the dummy portion 700 in the vertical direction (Z-axis direction) is larger than the area of the dummy via 600 in the vertical direction. The length of the dummy portion 700 in the up-down direction is shorter than the length of the dummy via 600 in the up-down direction (that is, the thickness dimension). In the present embodiment, the dummy portion 700 has a configuration similar to a flat conductive body for conduction (electrode pad 520 or the like) whose both ends are electrically connected to external terminals. It differs from a flat conductor in that it is not electrically connected. Further, the entirety of the dummy portion 700 is disposed between the suction surface S1 of the ceramic member 100 and the heater electrode 500 in the vertical direction, and is electrically connected to the dummy via 600. The arrangement of the dummy unit 700 will be described later in detail.

A-3-1. Configuration of Gas Inlet Forming Portion X1 in Ceramic Member 100:
As shown in FIG. 5, the gas flow inlet forming portion X1 in the ceramic member 100 has a first longitudinal flow communicating with a horizontal flow passage 114 farther from the center of the ceramic member 100 when viewed in the vertical direction (Z direction). This is the portion where the path 111 is formed. A plurality of (four in the present embodiment) first dummy vias 610 are provided in the gas inlet forming portion X1. At least a part of each first dummy via 610 overlaps the first vertical flow channel 111 when viewed in the vertical direction. Further, the plurality of first dummy vias 610 are arranged at regular intervals in the circumferential direction on a circle centered on the central axis of the first vertical flow path 111.

A-3-2. Configuration of coolant inlet port forming portion X2 in ceramic member 100:
As shown in FIGS. 2 and 5, a coolant supply hole 226 of the base member 200 is formed in the coolant inlet port forming portion X2 of the ceramic member 100 when viewed in the vertical direction (Z direction). A plurality of (four in the present embodiment) second dummy vias 620 and dummy portions 700 are provided in the coolant inlet port forming portion X2. At least a part of each second dummy via 620 overlaps with the coolant supply hole 226 when viewed in the vertical direction. Further, the plurality of second dummy vias 620 are arranged at equal intervals in the circumferential direction on a circle centered on the central axis of the coolant supply hole 226. The dummy unit 700 is disposed above the plurality of second dummy vias 620, and the lower surface of the dummy unit 700 is electrically connected to the upper end of each of the plurality of second dummy vias 620. When viewed in the up-down direction, the outline of the dummy portion 700 is located outside the coolant supply hole 226 over the entire circumference.

A-3-3. Configuration of hole forming portion X3 in ceramic member 100:
As shown in FIGS. 2 and 5, the hole forming portion X3 in the ceramic member 100 is a portion where the opening of the gas ejection channel 110 (gas ejection hole 102) is formed when viewed in the vertical direction (Z direction). is there. A plurality of (eight in the present embodiment) third dummy vias 630 are provided in the hole forming portion X3. The plurality of third dummy vias 630 are arranged so as to surround the opening of the gas ejection hole 102 when viewed in the up-down direction. The plurality of third dummy vias 630 are arranged at regular intervals in the circumferential direction on a circle centered on the central axis of the gas ejection hole 102.

A-3-4. Configuration of heater non-formed portion X4 in ceramic member 100:
As shown in FIG. 5, the heater non-formed portion X4 of the ceramic member 100 is a portion including a portion where the heater electrode 500 is not formed when viewed in the vertical direction (Z direction). In the heater non-formed portion X4, the fourth dummy via 640 is arranged at a position different from the heater electrode 500 when viewed in the vertical direction. Specifically, the fourth dummy via 640 is provided between the heater pad portions 508 of the heater electrode 500 when viewed in the vertical direction. Since the heater pad 508 of the heater electrode 500 has a relatively low temperature, it is particularly effective to dispose the fourth dummy via 640 near the heater pad 508.

The lower surface S2 of the ceramic member 100 corresponds to a second surface in the claims, and the upper surface S3 of the base member 200 corresponds to a third surface in the claims.
The suction surface S1 of the ceramic member 100 corresponds to a first surface in the claims, and the Z-axis direction corresponds to a first direction in the claims. The common external terminal 530 corresponds to an external terminal in the claims, and the adhesive layer 300 corresponds to a joint in the claims. Further, the gas ejection passage 110 corresponds to a gas passage in the claims, and the gas ejection hole 102 corresponds to a gas inlet in the claims. Further, the refrigerant flow path 210 corresponds to a refrigerant flow path in the claims, and the refrigerant supply hole 226 corresponds to a refrigerant inflow port in the claims.

A-4. Manufacturing method of the electrostatic chuck 10:
Next, a method for manufacturing the electrostatic chuck 10 according to the present embodiment will be described. FIG. 6 is a flowchart illustrating a method for manufacturing the electrostatic chuck 10 according to the present embodiment.

  First, for example, a plurality of ceramic green sheets mainly containing alumina are prepared, and necessary processing such as formation of through holes and filling of via ink is performed on each ceramic green sheet (S110). At this time, through holes and filling of via ink are performed on the ceramic green sheet to form not only the energizing vias (energizing vias 510) but also the dummy vias 600. That is, in the present embodiment, the formation of the through holes and the filling of the via ink for the formation of the energizing vias and the dummy vias 600 are performed collectively (at the same timing). As the via ink, for example, a metallized ink that is made into a slurry by mixing a tungsten powder with a raw material powder for a ceramic green sheet containing alumina as a main component is used.

  Next, necessary processing such as application of electrode ink is performed on some of the ceramic green sheets (S120). For example, a metallized ink for forming the chuck electrode 400, the heater electrode 500, or the electrode pad 520 is applied on one ceramic green sheet by, for example, screen printing. At this time, a metallized ink is applied to one ceramic green sheet for forming the dummy portion 700 as well as the current-carrying conductor (electrode pad 520). That is, in the present embodiment, the application of the electrode conductor ink for forming the electric conductor and the dummy portion 700 is performed collectively (at the same timing). In addition, as the electrode ink, for example, a metallized ink that is made into a slurry by mixing a tungsten powder with a raw material powder for a ceramic green sheet containing alumina as a main component is used.

  Next, a plurality of ceramic green sheets are laminated and thermocompression-bonded, and the laminate is cut into a predetermined shape and fired in a reducing atmosphere (for example, fired at 1400 to 1800 ° C. for 5 hours) (S130). ). By this baking treatment, the plurality of ceramic green sheets become the ceramic member 100, the layers of each metallized ink become the chuck electrode 400, the heater electrode 500, the electrode pad 520, and the dummy portion 700, and the portion filled with the via ink becomes The conductive via and the dummy via 600 are formed.

  Next, the ceramic member 100 and the base member 200 are joined using an adhesive such as a silicone resin, an acrylic resin, or an epoxy resin (S140). Thus, the manufacture of the electrostatic chuck 10 having the above-described configuration is completed.

A-5. Effects of this embodiment:
As described above, in the electrostatic chuck 10 according to the present embodiment, the ceramic member 100 includes the dummy via 600. The dummy via 600 is formed of a material having a higher thermal conductivity than the material of the ceramic member 100. Therefore, between the attraction surface S1 of the ceramic member 100 and the heater electrode 500, the heat conductivity of the portion where the dummy via 600 is arranged is higher than the heat conductivity of the portion where the dummy via 600 is not arranged. Further, the dummy via 600 is not electrically connected to any of the plurality of external terminals. That is, even during the operation of the electrostatic chuck 10 (during energization of the chuck electrode 400 and the heater electrode 500), no current flows through the dummy via 600, so that the dummy via 600 does not generate heat. Therefore, the dummy via 600 does not become a high temperature singular point due to heat generated by the dummy via 600 itself. Further, since the dummy via 600 extends in a direction substantially parallel to the vertical direction (Z-axis direction), the heat storage per unit area when viewed in the vertical direction is compared with, for example, the flat dummy portion 700 which spreads in the plane direction. High effect. Thus, according to the present embodiment, by arranging the dummy via 600, the temperature difference between the low-temperature portion having a relatively low temperature and the surrounding portion of the low-temperature portion on the suction surface S1 of the ceramic member 100 is reduced. Thus, the occurrence of a low-temperature singular point can be suppressed, and the temperature distribution on the adsorption surface S1 of the ceramic member 100 is controlled (for example, the temperature distribution on the adsorption surface S1 is changed to a predetermined temperature distribution (for example, when the temperature is substantially uniform). )). This will be specifically described later.

  Also, for example, as compared with the configuration in which the dummy via 600 is disposed between the heater electrode 500 and the lower surface S2 of the ceramic member 100, the dummy via 600 is disposed between the heater electrode 500 and the lower surface S2 of the ceramic member 100. Interference with the structure can be suppressed. That is, in this embodiment, the degree of freedom in the arrangement of the dummy via 600 and the dummy unit 700 is high.

  Further, for example, due to the structure of the base member 200, a difference occurs in a heat absorbing effect from the ceramic member 100 to the base member 200 between a specific position on the upper surface S3 of the base member 200 and another position, so-called heat absorption. Unevenness may occur. Even in the case where such heat absorption unevenness occurs in the base member 200, in the present embodiment, for example, the dummy via 600 is disposed at a position corresponding to a position where the heat absorption effect of the base member 200 is relatively large, so that a low temperature can be obtained. The occurrence of the temperature singularity can be suppressed, and the temperature distribution on the adsorption surface S1 of the ceramic member 100 can be controlled.

A-5-1. Temperature distribution in the surface area corresponding to the gas inlet forming portion X1 on the adsorption surface S1:
As shown in FIG. 5, a first vertical flow path 111 exists in the gas inlet forming portion X1 of the ceramic member 100. The first vertical channel 111 is an inlet for gas into the horizontal channel 114, and a relatively low-temperature gas before being heated by the heater electrode 500 flows from the first vertical channel 111 into the horizontal channel 114. . For this reason, the temperature of the connecting portion of the horizontal flow channel 114 with the first vertical flow channel 111 becomes low. Therefore, the surface region corresponding to the gas inlet forming portion X1 on the suction surface S1 is likely to be a low temperature singular point due to the internal structure (the first vertical flow path 111) of the electrostatic chuck 10.

  On the other hand, in the present embodiment, a plurality of first dummy vias 610 are arranged in the gas inlet forming portion X1, and at least a part of each first dummy via 610 is the first dummy via 610 when viewed in the vertical direction. It overlaps with the vertical channel 111. Thus, according to the present embodiment, it is possible to suppress the occurrence of a low-temperature singular point due to the presence of the first vertical flow channel 111 (the inlet of the horizontal flow channel 114). The uniformity of the temperature distribution on the surface S1 can be improved.

A-5-2. Temperature distribution in the surface area on the adsorption surface S1 corresponding to the coolant inlet port forming portion X2:
As shown in FIGS. 2 and 5, a coolant supply hole 226 is present in the coolant inlet forming portion X2 of the ceramic member 100 when viewed in the up-down direction (Z direction). The coolant supply hole 226 is an inflow port of the coolant CF into the coolant channel 210, and a relatively low-temperature coolant CF before being heated by the heat moving from the ceramic member 100 to the base member 200 passes through the coolant supply hole 226 through the coolant supply hole 226. It flows into the channel 210. Therefore, the temperature of the coolant supply hole 226 in the base member 200 becomes low. Therefore, the surface area corresponding to the coolant inlet port forming portion X2 on the adsorption surface S1 is likely to be a low temperature singular point due to the internal structure of the electrostatic chuck 10 (the coolant supply hole 226).

  On the other hand, in the present embodiment, a second dummy via 620 is provided in the coolant inlet port forming portion X2, and at least a part of each second dummy via 620 is viewed in the up-down direction (Z-axis direction). Overlaps the coolant supply holes 226. Thus, according to the present embodiment, it is possible to suppress the occurrence of a low-temperature singular point due to the presence of the coolant supply hole 226 (the inlet of the coolant channel 210). For example, the adsorption surface S1 of the ceramic member 100 Can improve the uniformity of the temperature distribution.

  Further, a dummy portion 700 is further provided in the coolant inlet port forming portion X2, and the dummy portion 700 is arranged above the second dummy via 620, and the lower surface of the dummy portion 700 is It is electrically connected to the upper end of the dummy via 620. As a result, the heat transmitted to the dummy via 600 is spread in the plane direction by the dummy portion 700. For this reason, according to the present embodiment, the heat accumulated in the dummy via 600 is dispersed in the plane direction, as compared with the configuration without the dummy section 700, so that the occurrence of a temperature singular point on the suction surface S1 is effectively prevented. And the temperature distribution on the suction surface S1 can be more effectively controlled. In addition, when viewed in the up-down direction, the dummy vias 600 are arranged in a relatively narrow space between the gas flow paths and the vicinity of the heater electrode 500, and the dummy section 700 is arranged in a relatively wide space. Accordingly, by dispersing the heat from the heater electrode 500 to the dummy via 600 in the plane direction from the dummy via 600 to the dummy portion 700, the temperature distribution on the suction surface S1 can be more effectively controlled.

A-5-3. Temperature distribution in the surface area corresponding to the hole forming portion X3 on the suction surface S1:
As shown in FIG. 2 and FIG. 5, an opening of the gas ejection channel 110 (gas ejection hole 102) exists in the hole forming portion X3 of the ceramic member 100. The gas ejection hole 102 is a gas outlet of the gas ejection channel 110, from which gas flows between the suction surface S <b> 1 and the wafer W. Therefore, the temperature near the gas ejection holes 102 between the suction surface S1 and the wafer W becomes low. Therefore, the surface area corresponding to the hole forming portion X3 on the suction surface S1 is likely to be a low-temperature singularity caused by the internal structure of the electrostatic chuck 10 (gas ejection hole 102).

  On the other hand, in the present embodiment, the plurality of third dummy vias 630 are provided in the hole forming portion X3, and the plurality of third dummy vias 630 are formed by opening the gas ejection holes 102 in the vertical direction. It is arranged to surround the part. Thus, according to the present embodiment, it is possible to suppress the generation of a low-temperature singular point due to the presence of the gas ejection flow channel 110 (the gas ejection holes 102). For example, the temperature at the adsorption surface S1 of the ceramic member 100 The uniformity of distribution can be improved.

A-5-4. Temperature distribution in the surface region corresponding to heater non-formed portion X4 on suction surface S1:
As shown in FIG. 5, the heater non-formed portion X4 includes a portion where the heater electrode 500 is not formed when viewed in the vertical direction (Z direction). Specifically, the fourth dummy via 640 is provided between the heater pad portions 508 of the heater electrode 500 when viewed in the vertical direction. Therefore, when viewed in the vertical direction, the temperature of the portion where the heater electrode 500 is not formed is lower than that of the portion where the heater electrode 500 is formed. Therefore, the surface area corresponding to the heater non-formed portion X4 on the suction surface S1 is likely to be a low temperature singularity due to the internal structure of the electrostatic chuck 10 (the portion where the heater electrode 500 is not formed).

  On the other hand, in the present embodiment, the fourth dummy via 640 is disposed in the heater non-formed portion X4, and the heater electrode 500 is formed on at least a part of the fourth dummy via 640 when viewed in the vertical direction. Overlaps with the missing part. Thus, according to the present embodiment, it is possible to suppress the occurrence of a low-temperature singular point due to the presence of the portion where the heater electrode 500 is not formed. For example, the temperature distribution on the adsorption surface S1 of the ceramic member 100 can be suppressed. Uniformity can be improved. Since the heater pad 508 of the heater electrode 500 has a relatively low temperature, it is particularly effective to arrange the fourth dummy via 640 near the heater pad 508.

B. 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 10 in the above embodiment is merely an example, and can be variously modified. For example, in the above embodiment, the common external terminal 530 and the like provided on the surface (lower surface S2) of the ceramic member 100 opposite to the suction surface S1 (first surface) are illustrated as the external terminals. The external terminal may be, for example, an external terminal provided in a concave portion on the lower surface S2 side of the ceramic member 100, or an external terminal provided on a surface side other than the suction surface S1 and the lower surface S2 in the ceramic member 100. It may be a terminal. Further, the shape of the external terminal is not limited to the rod shape, and may be, for example, a flat shape extending in a plane direction.

  Further, in the above embodiment, the suction surface S1 (first surface) of the ceramic member 100 is a flat surface, but may be, for example, a gentle concave surface or a surface on which a plurality of protrusions are formed. In short, the suction surface S1 only needs to be substantially flat.

  Further, the number of heater electrodes 500, the shape of each heater electrode 500, and the arrangement of each heater electrode 500 in the ceramic member 100 in the above embodiment are merely examples, and can be variously modified. For example, the electrostatic chuck 10 of the above embodiment includes two heater electrodes 500, but the number of heater electrodes 500 included in the electrostatic chuck 10 may be one, or may be three or more. Good. In the above-described embodiment, the plurality of heater electrodes 500 included in the electrostatic chuck 10 are arranged at the same position in the Z-axis direction. However, the plurality of heater electrodes 500 having different positions in the Z-axis direction are different from each other. A heater electrode 500 may be provided. Further, the heater electrode 500 may be electrically connected to the common external terminal 530 or the like via another conductor such as a driver electrode. In the above-described embodiment, the plurality of heater electrodes 500 may be electrically connected between a pair of different external terminals.

  Further, in the above embodiment, the bipolar method in which the pair of chuck electrodes 400 are provided inside the ceramic member 100 is adopted, but the monopolar method in which one chuck electrode 400 is provided inside the ceramic member 100 is used. May be employed.

  In the above embodiment, each dummy via 600 is not electrically connected to any external terminal. For example, each dummy via 600 is electrically connected to only one external terminal (for example, common external terminal 530). May be connected. In short, each of the dummy vias 600 is disposed inside the ceramic member 100 so that no current flows through the dummy via 600 when a voltage is applied to a conductor such as the chuck electrode 400 or the heater electrode 500 provided on the ceramic member 100. Whatever is done is good. The “dummy via that is not electrically connected to any of the plurality of external terminals” may include another conductor such as a heater electrode (an electrically conductive conductor that is electrically connected between a pair of external terminals and that can conduct electricity). ) Means that the terminal is not electrically connected to an external terminal.

  In the above-described embodiment, the dummy unit 700 is not electrically connected to any external terminal. For example, the dummy unit 700 is electrically connected to only one external terminal (for example, the common external terminal 530). May be connected. In short, the dummy portion 700 is provided inside the ceramic member 100 so that no current flows through the dummy portion 700 when a voltage is applied to a conductor such as the chuck electrode 400 or the heater electrode 500 provided on the ceramic member 100. What is necessary is just the thing arrange | positioned. The “dummy portion that is not electrically connected to any of the plurality of external terminals” includes another conductor such as a heater electrode (an electrically conductive material that is electrically connected between a pair of external terminals and that can conduct electricity). This means that a form electrically connected to an external terminal via the body is not included. In the above embodiment, the dummy portion is electrically connected to at least one end (at least one of the upper end and the lower end) of the first dummy via 610, the third dummy via 630, and the fourth dummy via 640. It may be. Further, the dummy portion may be electrically connected to the lower end of the second dummy via 620, or the dummy portion may not be electrically connected to any end of the second dummy via 620. .

  In the above-described embodiment, the dummy via 600 has a configuration similar to that of the energizing via 510. However, for example, the energizing via 510 includes at least one of a forming material and a shape (for example, length and thickness). One may have a different configuration. Specifically, the dummy via 600 may be formed of a material having a higher thermal conductivity or a material having a lower thermal conductivity than the material of the conductive via 510.

  Further, in the above embodiment, the dummy portion 700 has a configuration similar to that of the electrode pad 520 or the like. However, for example, the electrode pad 520 or the like has at least a forming material and a shape (for example, length and thickness). One may have a different configuration. Specifically, the dummy portion 700 may be formed of a material having a higher or lower thermal conductivity than the material of the electrode pad 520.

  In the above embodiment, the dummy vias 600 have substantially the same length in the Z-axis direction, but the dummy vias 600 have different lengths in the Z-axis direction according to the temperature distribution of the suction surface S1. A dummy via may be included. Further, the plurality of dummy vias 600 are arranged at substantially equal intervals from each other, but the plurality of dummy vias 600 may include a plurality of dummy vias whose arrangement intervals are different from each other according to the temperature distribution of the suction surface S1. Further, in the above embodiment, the electrostatic chuck 10 may not include any one of the first dummy via 610, the second dummy via 620, the third dummy via 630, and the fourth dummy via 640. In addition, the electrostatic chuck 10 may include a dummy via arranged at a position different from the above-described dummy via 600. For example, the electrostatic chuck 10 may include a dummy via arranged on the outer peripheral side of the heater electrode 500 when viewed in the vertical direction.

  Further, in the above embodiment, each via (dummy via 600, energizing via 510) may be configured by a single via, or may be configured by a group of a plurality of vias. In the above-described embodiment, each via may have a single-layer configuration including only a via portion, or a multi-layer configuration (for example, a configuration in which a via portion, a pad portion, and a via portion are stacked). Is also good.

  Further, the material forming each member in the electrostatic chuck 10 of the above embodiment is merely an example, and each member may be formed of another material. For example, in the above-described embodiment, the ceramic member 100 is exemplified as the plate-shaped member. However, the present invention is not limited to this. For example, a plate-shaped member formed of an insulating material other than ceramics (eg, polyimide resin) may be used. . Further, in the above embodiment, the dummy via 600 and the dummy portion 700 are formed of a conductive material, but may be formed of a material other than the conductive material. In short, the dummy vias 600 and the dummy portions 700 only need to be formed of a material having a higher thermal conductivity than the material of the plate member.

  Further, the present invention is not limited to the electrostatic chuck 10 that includes the ceramic member 100 and the base member 200 and holds the wafer W using electrostatic attraction, but also includes a plate-shaped member and a heater provided on the plate-shaped member. The present invention can be similarly applied to other holding devices (for example, a heater device such as a CVD heater, a vacuum chuck, or the like) that includes an electrode and holds an object on the surface of a plate member.

10: Electrostatic chuck 50: Heater electrode 100: Ceramic member 102: Gas ejection hole 110: Gas ejection channel 111: First vertical channel 112: Second vertical channel 114: Horizontal channel 200: Base member 210: Refrigerant flow path 220: Gas supply flow path 221: Gas source connection hole 222: Gas supply hole 224: Terminal hole 226: Refrigerant supply hole 228: Refrigerant discharge hole 300: Adhesive layer 310: Through hole 400: Chuck electrode 500: Heater Electrode 506: heater line section 508: heater pad section 510: via for conduction 520: electrode pad 530: common external terminal 600: dummy via 700: dummy section CF: refrigerant S1: adsorption surface S2: lower surface S3: upper surface S4: lower surface W: Wafer X1: Gas inlet forming part X2: Refrigerant inlet forming part X3: Hole forming part X4: heater non-forming part

Claims (5)

A plate member having a substantially planar first surface substantially perpendicular to the first direction;
A plurality of external terminals provided on the surface side of the plate-shaped member,
A heater electrode disposed inside the plate-shaped member and electrically connected to at least a pair of external terminals of the plurality of external terminals;
A holding device for holding an object on the first surface of the plate-like member,
The plate member,
A dummy via electrically connected to only one of the plurality of external terminals or not electrically connected to any of the plurality of external terminals, the material being a material for forming the plate-shaped member. A dummy via formed of a material having higher thermal conductivity, disposed between the first surface and the heater electrode in the first direction, and extending in a direction substantially parallel to the first direction. Has,
A holding device characterized by the above-mentioned. The holding device according to claim 1,
The plate-shaped member further comprises:
A dummy portion electrically connected to only one of the plurality of external terminals or not electrically connected to any of the plurality of external terminals; The dummy via is formed of a material having a higher thermal conductivity than the material, and has an area as viewed in a first direction larger than the area of the dummy via as viewed in the first direction, and is electrically connected to the dummy via. Equipped with a dummy part,
A holding device characterized by the above-mentioned. In the holding device according to claim 1 or 2,
A gas flow path is formed in the plate-like member,
In the first direction, at least a part of the dummy via overlaps a gas inlet in the gas flow path,
A holding device characterized by the above-mentioned. In the holding device according to any one of claims 1 to 3,
The plate-shaped member has a second surface disposed on the opposite side of the first surface in the first direction,
The holding device further comprises:
It has a third surface, the third surface is disposed so as to face the second surface of the plate-shaped member, and is formed of a material having a higher thermal conductivity than a material for forming the plate-shaped member. A base member,
A joint disposed between the second surface of the plate member and the third surface of the base member, for joining the plate member and the base member;
Comprising,
A holding device characterized by the above-mentioned. The holding device according to claim 4,
In the base member, a coolant channel is formed,
In the first direction, at least a portion of the dummy via overlaps with a coolant inlet in the coolant channel.
A holding device characterized by the above-mentioned.

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