Electrostatic chuck and substrate fixing device

Abstract

To improve the connection reliability of wiring passing through a chucking electrode.SOLUTION: An electrostatic chuck includes a ceramic plate, an attraction electrode, a ground electrode, and wiring. The attraction electrode is embedded near one surface of the ceramic plate. The ground electrode is disposed within the ceramic plate between the other surface of the ceramic plate and the attraction electrode and is connectable to a ground potential. The wiring is connected to the ground electrode within the ceramic plate and extends through the attraction electrode to one surface of the ceramic plate. The wiring includes a connection pad disposed at the same height position as the attraction electrode, a first via connecting the connection pad to the ground electrode or another connection pad disposed closer to the ground electrode side than the connection pad, and a second via connecting the connection pad to one surface of the ceramic plate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electrostatic chuck and a substrate fixing device. [Background technology]

[0002] Generally, a substrate clamping device that clamps and holds a substrate such as a wafer when manufacturing semiconductor parts, for example, is equipped with an electrostatic chuck (ESC) configured using a ceramic plate with a built-in clamping electrode. The substrate clamping device has a structure in which the electrostatic chuck is fixed to a base plate, and by applying a voltage to the clamping electrode built into the ceramic plate, the substrate is clamped to the electrostatic chuck using electrostatic force. By clamping and holding the substrate on the electrostatic chuck, processes such as micromachining and etching can be performed efficiently on the substrate.

[0003] The ceramic plate constituting the electrostatic chuck is formed by laminating and firing green sheets made of, for example, aluminum oxide and additives. An attraction electrode is built into the ceramic plate near the attraction surface that attracts the substrate. When the electrostatic chuck attracts a substrate, a voltage is applied to the attraction electrode, and when the substrate is released from the electrostatic chuck, the application of the voltage to the attraction electrode is stopped. Even when the application of the voltage to the attraction electrode is stopped, electric charge may remain on the attraction surface of the ceramic plate. The electric charge remaining on the attraction surface generates an attraction force corresponding to the electric charge between the attraction surface and the substrate, preventing the substrate from being released. Therefore, a ground electrode and wiring are formed inside the ceramic plate to dissipate the electric charge from the attraction surface to ground potential.

[0004] Specifically, a ground electrode connectable to a ground potential is formed on a green sheet stacked between the surface of the ceramic plate opposite the chucking surface and the chucking electrode, and conductive connecting pads are formed on the surface of each green sheet adjacent to this green sheet. Vias penetrating each green sheet connect the ground electrode to the connecting pad, the connecting pads of adjacent green sheets, and the connecting pads to the chucking surface, respectively. As a result, with multiple green sheets stacked, the connecting pads and vias formed on each green sheet form wiring that passes through the chucking electrode and connects the ground electrode to the chucking surface of the ceramic plate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-6762 Summary of the Invention [Problem to be solved by the invention]

[0006] However, an electrostatic chuck having wiring passing through an adsorption electrode formed therein has a problem in that the connection reliability of the wiring is reduced due to misalignment of the vias that occurs in the adsorption electrode where the wiring passes.

[0007] Specifically, in the wiring passage portion of the chucking electrode, a via penetrating the green sheet on which the chucking electrode is formed is connected to a via penetrating another green sheet on which the chucking electrode is not formed, thereby forming a wiring portion. The green sheet on which the chucking electrode is formed has more limited thermal shrinkage than the other green sheets on which the chucking electrode is not formed. Because the green sheet on which the chucking electrode is formed and the other green sheets are stacked and fired in this manner, after firing at high temperatures, the difference in the amount of thermal shrinkage between the green sheets causes misalignment of the vias in the wiring passage portion of the chucking electrode. As a result, the contact area of ​​the vias in the wiring passage portion of the chucking electrode becomes smaller, which hinders the connection between the vias and may result in poor resistance or disconnection of the wiring portion.

[0008] The disclosed technology has been made in view of the above, and aims to provide an electrostatic chuck and a substrate fixing device that can improve the connection reliability of wiring passing through an attraction electrode. [Means for solving the problem]

[0009] In one aspect, the electrostatic chuck disclosed herein includes a ceramic plate, an attraction electrode, a ground electrode, and wiring. The attraction electrode is embedded near one surface of the ceramic plate. The ground electrode is disposed within the ceramic plate between the other surface of the ceramic plate and the attraction electrode and is connectable to a ground potential. The wiring is connected to the ground electrode within the ceramic plate and extends through the attraction electrode to one surface of the ceramic plate. The wiring includes a connection pad disposed at the same height as the attraction electrode, a first via connecting the connection pad to the ground electrode or another connection pad disposed closer to the ground electrode than the connection pad, and a second via connecting the connection pad to one surface of the ceramic plate. [Effects of the Invention]

[0010] According to one aspect of the electrostatic chuck disclosed in the present application, it is possible to improve the connection reliability of the wiring passing through the chucking electrode. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing the configuration of a substrate fixing device according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing a cross section of the substrate fixing device according to the first embodiment. [Figure 3] FIG. 3 is a flowchart showing a method for manufacturing the substrate fixing device according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing a cross section of a substrate fixing device according to a modified example of the first embodiment. [Figure 5] FIG. 5 is a schematic diagram showing a cross section of a substrate fixing device according to the second embodiment. [Figure 6] FIG. 6 is a schematic diagram showing a cross section of a substrate fixing device according to the third embodiment. [Figure 7] FIG. 7 is a schematic diagram showing a cross section of a substrate fixing device according to the fourth embodiment. [Figure 8] FIG. 8 is a schematic diagram showing a cross section of a substrate fixing device according to the fifth embodiment. [Figure 9] FIG. 9 is a schematic diagram showing a cross section of a substrate fixing device according to the sixth embodiment. [Figure 10] FIG. 10 is a schematic diagram showing a cross section of a substrate fixing device according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of an electrostatic chuck and a substrate fixing device disclosed in the present application will be described in detail with reference to the drawings. Note that the disclosed technology is not limited to these embodiments. Furthermore, the respective embodiments can be appropriately combined. Furthermore, the same components in the following embodiments are denoted by the same reference numerals, and redundant explanations will be omitted.

[0013] (First embodiment) 1 is a perspective view showing the configuration of a substrate fixing device 100 according to the first embodiment. The substrate fixing device 100 shown in FIG.

[0014] The base plate 110 is a circular member made of metal such as aluminum. The base plate 110 is a base material for fixing the electrostatic chuck 120. The base plate 110 is attached to, for example, a semiconductor manufacturing apparatus, and causes the substrate fixing device 100 to function as a semiconductor holding device for holding a wafer. Note that the base plate 110 may be attached to, for example, an exposure device, a machining device, a bonding device, a measuring device, or an inspection device in addition to the semiconductor manufacturing apparatus, and causes the substrate fixing device 100 to function as a semiconductor holding device.

[0015] The electrostatic chuck 120 is attached to the base plate 110 and uses electrostatic force to attract an object such as a wafer. The electrostatic chuck 120 is a circular member with a smaller diameter than the base plate 110, and one surface is attached to the center of the base plate 110. The electrostatic chuck 120 attracts an object such as a wafer to an attracting surface opposite to the bonding surface attached to the base plate 110. That is, the electrostatic chuck 120 is made of ceramic with an attracting electrode built in near the attracting surface, and when a voltage is applied to the attracting electrode from the base plate 110, the object is attracted to the attracting surface by electrostatic force.

[0016] Fig. 2 is a schematic diagram showing a cross section of the substrate fixing device 100 according to the first embodiment. Fig. 2 shows a schematic cross section taken along line II-II in Fig. 1. As shown in Fig. 2, the substrate fixing device 100 is configured by bonding an electrostatic chuck 120 to a base plate 110 with an adhesive layer 200. For convenience, the following description will be given assuming that the direction from the base plate 110 to the electrostatic chuck 120 is the upward direction, and the direction from the electrostatic chuck 120 to the base plate 110 is the downward direction. However, the substrate fixing device 100 may be manufactured and used in any orientation, such as upside down.

[0017] The base plate 110 is a member made of a metal such as aluminum and has a thickness of 5 to 100 mm. A power supply line 115 is provided to pass through the base plate 110. The power supply line 115 is formed, for example, in the shape of a pin, and passes through the adhesive layer 200 to connect to a power supply pad 130 of the electrostatic chuck 120. When the power supply line 115 comes into contact with the power supply pad 130, power is supplied to wiring 150 inside the electrostatic chuck 120. A switch 115a is connected to the power supply line 115. The switch 115a can switch between a connection between the power supply line 115 and the anode or cathode of a DC power supply 115b and a connection between the power supply line 115 and ground potential.

[0018] A ground wire 116 is provided to pass through the base plate 110. The ground wire 116 is switched by a switch 116a between a state where it is connected to the ground potential and a state where it is not connected to the ground potential. The ground wire 116 is formed, for example, in a pin shape, passes through the adhesive layer 200, and is connected to the ground pad 140 of the electrostatic chuck 120. The wiring 180 connected to the ground electrode 170 and the ground wire 116 are connected to the ground potential, so that the ground pad 140 is connected to the ground potential.

[0019] The electrostatic chuck 120 has built-in conductive wiring 150 and is made of a ceramic plate obtained by, for example, firing aluminum oxide. The thickness of the electrostatic chuck 120 is, for example, about 1 to 20 mm. A cavity 120b, which is a recess capable of accommodating the power supply line 115 of the base plate 110, is formed around the outer periphery of the lower surface of the electrostatic chuck 120, and the lower surface of the power supply pad 130 is exposed in the cavity 120b. When the tip of the power supply line 115 comes into contact with the lower surface of the power supply pad 130, power is supplied from the base plate 110 to the wiring 150 in the electrostatic chuck 120.

[0020] The upper surface of the electrostatic chuck 120 is an attraction surface 120a that attracts an object. An attraction electrode 160 for generating electrostatic force is built in near the attraction surface 120a. A power supply pad 130 that contacts the power supply line 115 is built in near the lower surface of the electrostatic chuck 120 opposite the attraction surface 120a. The power supply pad 130 and the attraction electrode 160 are electrically connected by wiring 150 that is configured by stacking multiple connection pads 151 and vias 152. In other words, multiple layers of connection pads 151 are arranged between the power supply pad 130 that contacts the power supply line 115 and the attraction electrode 160. The power supply pad 130 and the connection pad 151, adjacent connection pads 151, and the connection pad 151 and the attraction electrode 160 are connected by vias 152, respectively.

[0021] In the configuration shown in FIG. 2, the chucking electrode 160 is a bipolar electrode separated into a first electrode 160A and a second electrode 160B. The first electrode 160A is a positive electrode connectable to the positive electrode of the DC power supply 115b, and the second electrode 160B is a negative electrode connectable to the negative electrode of the DC power supply 115b. The first electrode 160A and the second electrode 160B each include a plurality of semicircular arc-shaped conductor patterns arranged concentrically, and are disposed inside the electrostatic chuck 120 such that the chord sides of the semicircular arcs face each other. Each of the first electrode 160A and the second electrode 160B includes a passing portion 161 through which a ground wiring 190 (described later) passes. The passing portion 161 may be, for example, a gap between the conductor patterns of the first electrode 160A and the second electrode 160B. Alternatively, the passing portion 161 may be, for example, a through-hole penetrating the chucking electrode 160 in the thickness direction.

[0022] The first electrode 160A and the second electrode 160B may each be made of a semicircular conductor pattern and disposed inside the electrostatic chuck 120 so that the chord sides of the semicircles face each other. In this case, the passing portion 161 may be, for example, a through-hole that penetrates the chucking electrode 160 in the thickness direction.

[0023] The wiring 150 is arranged in two sets on the left and right according to the first electrode 160A and the second electrode 160B of the chucking electrode 160, and each wiring 150 is formed by stacking two layers of connection pads 151 between the power supply pad 130 and the chucking electrode 160.

[0024] The connection pads 151 are formed of a conductive material such as tungsten or molybdenum, and the vias 152 are formed by filling via holes formed between the connection pads 151 of adjacent layers with a conductive material such as tungsten or molybdenum.

[0025] A ground electrode 170 is disposed within the electrostatic chuck 120 between the lower surface of the electrostatic chuck 120 and the chucking electrode 160. The ground electrode 170 is disposed, for example, at the same height as the connecting pad 151 closest to the chucking electrode 160. The ground electrode 170 is made of a metal such as tungsten or molybdenum, has a circular pattern with a diameter of approximately 270 to 300 mm and a thickness of approximately 10 to 50 μm, and is configured to be connectable to a ground potential. Specifically, a cavity 120c, which is a recess capable of accommodating the end of the ground wire 116 of the base plate 110, is formed in the center of the lower surface of the electrostatic chuck 120. The cavity 120c exposes the lower surface of the ground pad 140, which contacts the ground wire 116. The ground pad 140 and the ground electrode 170 are connected by wiring 180 configured by stacking a connecting pad 181 and a via 182.

[0026] The end of the ground wire 116, which is connected to the ground potential, is connected to the lower surface of the ground pad 140, thereby connecting the ground electrode 170 to the ground potential. For example, when an object is attracted to the attracting surface 120a of the electrostatic chuck 120, the power supply line 115 is connected to the anode or cathode of the DC power supply 115b by the switch 115a, and the ground wire 116 is disconnected from the ground potential by the switch 116a. This disconnects the ground electrode 170 from the ground potential. On the other hand, when an object is released from the attracting surface 120a, the power supply line 115 is connected to the ground potential by the switch 115a, and the ground wire 116 is connected to the ground potential by the switch 116a. This connects the ground electrode 170 to the ground potential.

[0027] A ground wiring 190 (an example of wiring) configured by laminating a connecting pad 191 and vias 192 and 193 is connected to the ground electrode 170. The ground wiring 190 passes through the passing portion 161 of the chucking electrode 160 and extends to the attracting surface 120a of the electrostatic chuck 120. The ground electrode 170 and the attracting surface 120a are electrically connected by the ground wiring 190 configured by laminating the connecting pad 191 and vias 192 and 193. That is, for example, a single layer of connecting pad 191 is disposed between the ground electrode 170 and the attracting surface 120a. The ground electrode 170 and the connecting pad 191 are connected by a via 192 (an example of a first via), and the connecting pad 191 and the attracting surface 120a are connected by a via 193 (an example of a second via). An end face of the via 193, i.e., an end face of the ground wiring 190, is exposed from the attracting surface 120a.

[0028] In this manner, a ground electrode 170 connectable to a ground potential is disposed within the electrostatic chuck 120, and a ground wiring 190 extending to the attracting surface 120a is connected to the ground electrode 170. Therefore, when the application of voltage to the attracting electrode 160 is stopped, the charge remaining on the attracting surface 120a can be released to the ground electrode 170 via the ground wiring 190. In other words, the amount of charge remaining on the attracting surface 120a is reduced, thereby reducing the attracting force between the attracting surface 120a and the wafer due to the charge on the attracting surface 120a. As a result, it is possible to facilitate detachment of the wafer from the attracting surface 120a.

[0029] 2, two sets of ground wirings 190 are arranged on the left and right sides in accordance with the first electrode 160A and the second electrode 160B of the chucking electrode 160. Each ground wiring 190 is formed by laminating one layer of connection pads 191 and vias 192 and 193 between the ground electrode 170 and the chucking surface 120a.

[0030] The connection pad 191 is formed of a conductive material such as tungsten or molybdenum. The via 192 is formed by filling a via hole formed between the ground electrode 170 and the connection pad 191 with a conductive material such as tungsten or molybdenum. The via 193 is formed by filling a via hole formed between the connection pad 191 and the chucking surface 120a with a conductive material such as tungsten or molybdenum.

[0031] The linking pad 191 is disposed at the same height as the chucking electrode 160 in the thickness direction of the electrostatic chuck 120. That is, the linking pad 191 is disposed in the passing portion 161 of the chucking electrode 160 while being electrically independent from the chucking electrode 160, and is disposed in the same layer as the chucking electrode 160 in a side view. The lower surface of the linking pad 191 is connected to the upper surface of the chucking electrode 160 by a via 192. The lower surface of the linking pad 191 has a larger area than the end surface of the via 192 that contacts the linking pad 191. The upper surface of the linking pad 191 is connected to the chucking surface 120a of the electrostatic chuck 120 by a via 193. The upper surface of the linking pad 191 has a larger area than the end surface of the via 193 that contacts the linking pad 191.

[0032] As described above, in the embodiment, the connection pad 191 of the ground wiring 190 is disposed at the same height as the chucking electrode 160, the connection pad 191 and the ground electrode 170 are connected by the via 192, and the connection pad 191 and the chucking surface 120a are connected by the via 193. That is, at the passing portion 161 of the ground wiring 190 in the chucking electrode 160, the via 192 and the via 193 are not directly connected to each other but are connected to each other via the connection pad 191. Therefore, even if the vias 192 and 193 are misaligned in the horizontal direction at the passing portion 161 of the chucking electrode 160 due to differences in the amount of thermal contraction between the green sheets constituting the electrostatic chuck 120 (ceramic plate), it is possible to prevent the connection between the vias 192 and 193 from being impaired. As a result, the connection reliability of the ground wiring 190 can be improved.

[0033] The via 193 has an end face exposed from the attracting surface 120a of the electrostatic chuck 120. The exposed end face of the via 193 may be located on the same plane as the attracting surface 120a. The exposed end face of the via 193 may be located at a position lower than the attracting surface 120a. By exposing the end face of the via 193 from the attracting surface 120a, charges accumulated on the attracting surface 120a can be quickly released to the ground electrode 170, making it easier to detach the wafer from the attracting surface 120a.

[0034] Furthermore, the connection pad 191 is electrically independent from the chucking electrode 160 and is disposed in the passage portion 161 of the chucking electrode 160. This makes it possible to suppress a decrease in electrostatic force caused by leakage from the chucking electrode 160 to the connection pad 191.

[0035] Next, a method for manufacturing the substrate fixing device 100 according to the first embodiment will be described with reference to Fig. 3. Fig. 3 is a flowchart showing the method for manufacturing the substrate fixing device 100 according to the first embodiment.

[0036] First, a plurality of green sheets are prepared to form the electrostatic chuck 120 (step S101). Specifically, for example, aluminum oxide and a predetermined auxiliary agent are mixed together, and the resulting slurry mixture is dried to prepare the green sheets. The green sheets are, for example, 0.7 mm thick and square sheets measuring 500 mm x 500 mm.

[0037] Vias 152 and 182 are formed in each green sheet to connect the connecting pads 151 and 181 of adjacent layers. Also, a via 192 for connecting the ground electrode 170 and the connecting pad 191, or a via 193 for connecting the chucking surface 120a and the connecting pad 191 is appropriately formed in each green sheet (step S102). Specifically, at the position where the connecting pads 151 and 181 of adjacent layers overlap, a via hole is formed penetrating the green sheet, and the via hole is filled with a conductor such as tungsten or molybdenum, thereby forming the vias 152 and 182. Also, at the position where the ground electrode 170 and the connecting pad 191 overlap, a via hole is formed penetrating the green sheet, and the via hole is filled with a conductor such as tungsten or molybdenum, thereby forming the via 192. Furthermore, a via hole is formed through the green sheet at the position where the chucking surface 120a and the connection pad 191 overlap, and the via hole is filled with a conductor such as tungsten or molybdenum, thereby forming a via 193.

[0038] Like via holes, the cavities 120b and 120c are formed from through holes that penetrate the green sheets. That is, the through holes of the stacked green sheets are connected to form openings, thereby forming the cavities 120b and 120c.

[0039] The patterns of the connection pads 151 and 181 are printed on the green sheet on which the vias 152 and 182 are formed, and the pattern of the connection pad 191 is printed on the green sheet on which the vias 192 are formed (step S103). That is, the connection pads 151, 181, and 191 are formed by printing a metal paste such as tungsten or molybdenum on the surface of the green sheet.

[0040] Furthermore, the chucking electrode 160 is formed on the green sheet on which the connection pad 191 is formed and which is laminated near the chucking surface 120a of the electrostatic chuck 120 (step S104). At this time, a passing portion 161 through which the ground wiring 190 passes is formed in the chucking electrode 160, and the connection pad 191 is accommodated in the passing portion 161. As a result, the connection pad 191 and the chucking electrode 160 are disposed on the same layer.

[0041] Furthermore, a ground electrode 170 is formed on the green sheet laminated between the lower surface of the electrostatic chuck 120 opposite to the attracting surface 120a and the attracting electrode 160 (step S105).

[0042] The green sheets on which the connection pads 151, 181, and 191, the chucking electrodes 160, and the ground electrodes 170 are formed are stacked one on top of the other (step S106). That is, the green sheets are stacked in this order so that the connection pads 151, 181, the chucking electrodes 160, and the ground electrodes 170 of adjacent layers are connected by the vias 152 and 182, and the connection pad 191, the ground electrodes 170, and the chucking surface 120a are connected by the vias 192 and 193. As a result, the connection pads 151 and the vias 152 are stacked to form the wiring 150, and the connection pads 181 and the vias 182 are stacked to form the wiring 180. Furthermore, the connection pads 191 and the vias 192 and 193 are stacked to form the ground wiring 190. The end face of the via 193, i.e., the end face of the ground wiring 190, is exposed on the chucking surface 120a. The stack of green sheets is then cut into a circle to fit the shape of the base plate 110 (step S107).

[0043] The laminate cut into a circle is fired in a firing furnace to become ceramic (step S108). The firing causes the laminate to thermally shrink. At this time, differences in the amount of thermal shrinkage between the green sheets constituting the laminate cause horizontal positional deviation of the vias 192 and 193 at the passing portion 161 of the chucking electrode 160. However, because the vias 192 and 193 are connected via the connection pad 191, it is possible to prevent the connection between the vias 192 and 193 from being obstructed. As a result, the connection reliability of the ground wiring 190 can be improved even during firing, which exposes the laminate to high temperatures.

[0044] The thickness of the ceramic circular plate obtained by firing is, for example, about 10 mm. Because the laminated body thermally shrinks during firing, the thickness of the circular plate becomes thinner than the thickness of the laminated body before firing. The ceramic circular plate thus formed becomes the electrostatic chuck 120, and the electrostatic chuck 120 is adhered to the metal base plate 110 by an adhesive layer 200 (step S109). The adhesive layer 200 is formed using, for example, a bonding material. In this way, the substrate fixing device 100 is completed.

[0045] As described above, the electrostatic chuck (e.g., electrostatic chuck 120) according to the first embodiment includes a ceramic plate, an adsorption electrode (e.g., adsorption electrode 160), a ground electrode (e.g., ground electrode 170), and wiring (e.g., ground wiring 190). The adsorption electrode is embedded near one surface (e.g., adsorption surface 120a) of the ceramic plate. The ground electrode is disposed within the ceramic plate between the other surface of the ceramic plate and the adsorption electrode and is connectable to a ground potential. The wiring is connected to the ground electrode within the ceramic plate, passes through the adsorption electrode, and extends to one surface of the ceramic plate. The wiring includes a connection pad (e.g., connection pad 191) disposed at the same height as the adsorption electrode, a first via (e.g., via 192) connecting the connection pad to the ground electrode, and a second via (e.g., via 193) connecting the connection pad to one surface of the ceramic plate. This improves the connection reliability of the wiring passing through the adsorption electrode.

[0046] Furthermore, the vias 193 may have end faces exposed from one surface of the ceramic plate, which makes it easier to detach the wafer from the chucking surface.

[0047] The chucking electrode may also have a passage (e.g., passage 161) through which the wiring passes. The connection pad may be disposed in the passage electrically independent of the chucking electrode. This makes it possible to suppress a decrease in electrostatic force due to leakage from the chucking electrode to the connection pad.

[0048] It should be noted that various modifications can be made to the arrangement of the ground electrode 170 and the structure of the ground wiring 190 described in the first embodiment. Modifications of the substrate fixing device 100 will now be described in detail.

[0049] 4 is a schematic diagram showing a cross section of a substrate fixing device 100 according to a modified example of the first embodiment. In FIG. 4, the same parts as in FIG. 2 are denoted by the same reference numerals.

[0050] 4, in the substrate fixing device 100 according to the modified example, the ground electrode 170 is disposed at the same height as the connecting pad 151 that is farthest from the chucking electrode 160. The ground electrode 170 and the ground pad 140 are connected by a wiring 180 consisting only of a via 182.

[0051] The ground electrode 170 and the suction surface 120a are electrically connected by a ground wiring 190 configured by stacking connecting pads 191 and 194 and vias 192, 193, and 195. That is, for example, two adjacent connecting pads 191 and 194 are arranged between the ground electrode 170 and the suction surface 120a. The connecting pad 194 (an example of another connecting pad) is arranged closer to the ground electrode 170 than the connecting pad 191. The ground electrode 170 and the connecting pad 194 are connected by a via 195, the adjacent connecting pads 191 and 194 are connected by a via 192 (an example of a first via), and the connecting pad 191 and the suction surface 120a are connected by a via 193 (an example of a second via). The end face of the via 193, i.e., the end face of the ground wiring 190, is exposed from the suction surface 120a.

[0052] As described above, in the substrate fixing device 100 according to the modified example, the via 192 of the ground electrode 170 connects the connecting pad 191 arranged in the passing portion 161 of the chucking electrode 160 to the connecting pad 194 arranged closer to the ground electrode 170 than the connecting pad 191. Even in this case, the via 192 and the via 193 are connected to each other through the connecting pad 191 in the passing portion 161 of the chucking electrode 160, so that it is possible to prevent the connection between the via 192 and the via 193 from being obstructed, and it is possible to improve the connection reliability of the ground wiring 190.

[0053] Furthermore, the size of the connection pad 191 in the direction perpendicular to the extending direction of the ground wiring 190 (horizontal direction) may be smaller than that of the connection pad 194. This allows the size of the passing portion 161 in the chucking electrode 160 to be reduced, and as a result, it is possible to suppress a decrease in electrostatic force caused by a decrease in the volume of the chucking electrode 160.

[0054] (Second embodiment) The second embodiment relates to a variation of the structure of the attracting surface 120a of the electrostatic chuck 120 in the first embodiment.

[0055] 5 is a schematic diagram showing a cross section of the substrate fixing device 100 according to the second embodiment. In FIG. 5, the same parts as in FIG. 2 are denoted by the same reference numerals.

[0056] 5, in the second embodiment, a recess 120d may be formed in the attracting surface 120a of the electrostatic chuck 120. The recess 120d is formed to surround a predetermined region including an end face of the via 193 exposed from the attracting surface 120a. The recess 120d is formed, for example, by blasting the attracting surface 120a in a state where a mask is formed on the predetermined region including the end face of the via 193 exposed from the attracting surface 120a. The depth of the recess 120d can be, for example, about 10 μm.

[0057] In this way, by forming a recess 120d on the adsorption surface 120a of the electrostatic chuck 120, which surrounds a predetermined area including the exposed end face of the via 193, the contact area between the adsorption surface 120a and the wafer can be reduced, thereby suppressing damage to the wafer.

[0058] (Third embodiment) The third embodiment differs from the second embodiment in that an insulating film is formed on the attracting surface 120a of the electrostatic chuck 120.

[0059] 6 is a schematic diagram showing a cross section of the substrate fixing device 100 according to the third embodiment. In FIG. 6, the same parts as in FIG. 5 are denoted by the same reference numerals.

[0060] 6, in the third embodiment, an insulating film 210 may be formed on the attracting surface 120a of the electrostatic chuck 120. The insulating film 210 covers the attracting surface 120a of the electrostatic chuck 120 and the end faces of the vias 193 exposed from the attracting surface 120a. If a recess 120d is formed in the attracting surface 120a, the insulating film 210 also covers the inner surface of the recess 120d. The insulating film 210 is formed by thermal spraying, deposition, sputtering, or CVD (Chemical Vapor Deposition) using a material such as aluminum oxide, yttrium oxide, silicon oxide (SiO), silicon nitride (SiN), or diamond-like carbon. The insulating film 210 may have a thickness of, for example, about 0.1 to 1 μm.

[0061] In this way, by covering the chucking surface 120a of the electrostatic chuck 120 and the end surface of the via 193 exposed from the chucking surface 120a with the insulating film 210, the generation of particles due to contact between the via 193 and the wafer can be suppressed.

[0062] (Fourth embodiment) The fourth embodiment differs from the third embodiment in the coverage area of ​​the insulating film 210.

[0063] 7 is a schematic diagram showing a cross section of a substrate fixing device 100 according to a fourth embodiment. In FIG. 7, the same parts as in FIG. 6 are denoted by the same reference numerals.

[0064] 7, in the fourth embodiment, the insulating film 210 covers only the end face exposed from the suction surface 120a of the via 193 and the suction surface 120a around this end face. This makes it possible to reduce the coverage area of ​​the insulating film 210 compared to the third embodiment, and therefore the amount of material used for the insulating film 210 can be reduced.

[0065] (Fifth embodiment) The fifth embodiment differs from the first embodiment in the structure of the via 193 in the ground wiring 190.

[0066] 8 is a schematic diagram showing a cross section of the substrate fixing device 100 according to the fifth embodiment. In FIG. 8, the same parts as in FIG. 2 are denoted by the same reference numerals.

[0067] 8, in the fifth embodiment, the end of the via 193 may protrude from the chucking surface 120a. Therefore, the via 193 comes into contact with the wafer chucking to the chucking surface 120a. This allows the charge accumulated on the chucking surface 120a as well as on the wafer to be quickly released to the ground electrode 170, making it easier to detach the wafer from the chucking surface 120a.

[0068] The end of the via 193 protruding from the suction surface 120a is formed by blasting the area of ​​the suction surface 120a that does not overlap with the via 193.

[0069] (Sixth embodiment) The sixth embodiment differs from the fifth embodiment in that an insulating film is formed on the attracting surface 120a of the electrostatic chuck 120.

[0070] 9 is a schematic diagram showing a cross section of the substrate fixing device 100 according to the sixth embodiment. In FIG. 9, the same parts as in FIG. 8 are denoted by the same reference numerals.

[0071] 9, in the sixth embodiment, an insulating film 220 may be formed on the attracting surface 120a of the electrostatic chuck 120. The insulating film 220 covers the attracting surface 120a of the electrostatic chuck 120 and the end portions of the vias 193 that protrude from the attracting surface 120a. The insulating film 220 is formed by thermal spraying, vapor deposition, sputtering, or CVD using a material such as aluminum oxide, yttrium oxide, silicon oxide (SiO), silicon nitride (SiN), or diamond-like carbon. The insulating film 220 may have a thickness of, for example, about 0.1 to 1 μm.

[0072] In this way, by covering the chucking surface 120a of the electrostatic chuck 120 and the end of the via 193 protruding from the chucking surface 120a with the insulating film 220, the generation of particles due to contact between the via 193 and the wafer can be suppressed.

[0073] (Seventh embodiment) The seventh embodiment differs from the sixth embodiment in the coverage area of ​​the insulating film 220.

[0074] 10 is a schematic diagram showing a cross section of the substrate fixing device 100 according to the seventh embodiment. In FIG. 10, the same parts as in FIG. 9 are denoted by the same reference numerals.

[0075] 10, in the seventh embodiment, the insulating film 220 covers only the end face of the via 193 protruding from the suction surface 120a and the suction surface 120a around this end face. This makes it possible to reduce the coverage area of ​​the insulating film 220 compared to the sixth embodiment, and therefore the amount of material used for the insulating film 220 can be reduced.

[0076] (others) In the above embodiments, the chucking electrode 160 is a bipolar electrode, but the chucking electrode 160 may be a unipolar electrode. For example, the chucking electrode 160 may be formed from a single, unseparated, disk-shaped conductor pattern. In this case, one pair of the power supply pad 130 and the wiring 150 is arranged for the chucking electrode 160.

[0077] Even when the chucking electrode 160 is a monopolar electrode, a ground electrode 170 is disposed within the electrostatic chuck 120 and a ground wiring 190 is connected to the ground electrode 170, so that the charge on the chucking surface 120a can be released to the ground electrode 170 via the ground wiring 190. [Explanation of symbols]

[0078] 100 Board fixing device 110 base plate 120 Electrostatic Chuck 120a Adsorption surface 130 Power Pad 140 Grounding Pad 150 Wiring 160 Adsorption electrode 161 Passage section 170 Ground electrode 180 Wiring 190 Ground wiring 191, 194 Connecting pad 192, 193, 195 via 200 Adhesive layer 210, 220 insulating film

Claims

1. Ceramic plate and an adsorption electrode built in near one surface of the ceramic plate; a ground electrode that is disposed within the ceramic plate between the other surface of the ceramic plate and the chucking electrode and that can be connected to a ground potential; a wiring connected to the ground electrode within the ceramic plate, passing through the chucking electrode, and extending to one surface of the ceramic plate; and The wiring is a connection pad disposed at the same height as the chucking electrode; a first via that connects the connection pad to the ground electrode or another connection pad that is disposed closer to the ground electrode than the connection pad; a second via connecting the connection pad and one surface of the ceramic plate; An electrostatic chuck comprising:

2. The second via is The ceramic plate has an end surface exposed from one side thereof.

2. The electrostatic chuck of claim 1.

3. One surface of the ceramic plate is a recess surrounding a predetermined region including the exposed end face of the second via; 3. The electrostatic chuck of claim 2.

4. an insulating film covering one surface of the ceramic plate and the exposed end surface of the second via; 3. The electrostatic chuck of claim 2, further comprising:

5. The second via is The ceramic plate has an end portion protruding from one surface thereof.

2. The electrostatic chuck of claim 1.

6. 6. The electrostatic chuck according to claim 5, further comprising an insulating film that covers one surface of the ceramic plate and the protruding end of the second via.

7. The chucking electrode is a passage portion through which the wiring passes, The connection pad is The electrode is electrically independent from the chucking electrode and is disposed in the passage portion.

2. The electrostatic chuck of claim 1.

8. The first via is connecting the connection pad disposed in the passing portion to the other connection pad; The connection pad is The size of the connecting pad in the direction perpendicular to the extending direction of the wiring is smaller than that of the other connecting pads.

8. The electrostatic chuck of claim 7.

9. A base plate and an electrostatic chuck fixed to the base plate and configured to attract the substrate by electrostatic force; The electrostatic chuck comprises: Ceramic plate and an adsorption electrode built in near one surface of the ceramic plate; a ground electrode that is disposed within the ceramic plate between the other surface of the ceramic plate and the chucking electrode and that can be connected to a ground potential; a wiring connected to the ground electrode within the ceramic plate, passing through the chucking electrode, and extending to one surface of the ceramic plate; and The wiring is a connection pad disposed at the same height as the chucking electrode; a first via that connects the connection pad to the ground electrode or another connection pad that is disposed closer to the ground electrode than the connection pad; a second via connecting the connection pad and one surface of the ceramic plate; A substrate fixing device comprising:

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