Electrostatic chuck and substrate holding apparatus

Abstract

The present invention provides an electrostatic chuck and a substrate fixing device. The electrostatic chuck includes a ceramic plate, an adsorption electrode, a grounding electrode, and a wiring. The adsorption electrode is built in the vicinity of one surface of the ceramic plate. The grounding electrode is arranged in the ceramic plate between the other surface of the ceramic plate and the adsorption electrode, and can be connected to a ground potential. The wiring is connected to the grounding electrode in the ceramic plate, and extends to one surface of the ceramic plate.

Description

Technical Field

[0001] This invention relates to electrostatic chucks and substrate fixing devices. Background Technology

[0002] A substrate holder is configured to adsorb and hold devices such as wafers during the manufacture of semiconductor components. This substrate holder includes an electrostatic chuck (ESC) made of a ceramic plate with built-in adsorption electrodes. The substrate holder has a structure in which the electrostatic chuck is fixed to a base plate and configured to apply a voltage to the adsorption electrodes built into the ceramic plate, thereby using electrostatic force to adsorb the substrate onto the electrostatic chuck. By adsorbing and holding the substrate on the electrostatic chuck, microfabrication, etching, and other processing on the substrate can be performed efficiently.

[0003] Citation List

[0004] Patent documents

[0005] Patent Document 1: JP-A-2013-542590 Summary of the Invention

[0006] Meanwhile, in the substrate fixing device, when the processing of the substrate is finished, the voltage applied to the adsorption electrode is stopped to release the electrostatic force in the electrostatic chuck, and the substrate is separated from the adsorption surface of the electrostatic chuck by using lifting pins or the like.

[0007] However, even when the voltage applied to the adsorption electrode is stopped, residual charge remains on the adsorption surface of the electrostatic chuck. When the adsorption surface is charged, the adsorption force corresponding to the charge remains between the adsorption surface and the substrate, which may hinder the separation of the substrate from the adsorption surface.

[0008] A non-limiting aspect of this disclosure is to provide an electrostatic chuck and substrate fixing device that can facilitate substrate separation.

[0009] In one aspect, the electrostatic chuck of this disclosure includes a ceramic plate, an adsorption electrode, a grounding electrode, and wiring. The adsorption electrode is embedded near one surface of the ceramic plate. The grounding electrode is disposed in the ceramic plate between the other surface of the ceramic plate and the adsorption electrode, and can be connected to a ground potential. The wiring is connected to the grounding electrode in the ceramic plate and extends to one surface of the ceramic plate.

[0010] According to one aspect of the electrostatic chuck disclosed herein, an effect that can promote the separation of substrates is achieved. Attached Figure Description

[0011] Figure 1 This is a perspective view showing the structure of the substrate fixing device according to the first embodiment.

[0012] Figure 2This is a schematic diagram showing a cross-section of the substrate fixing device according to the first embodiment.

[0013] Figure 3 This is a flowchart illustrating a method for manufacturing a substrate fixing device according to the first embodiment.

[0014] Figure 4 This is a schematic diagram showing a cross-section of the substrate fixing device according to the second embodiment.

[0015] Figure 5 This is a schematic diagram showing a cross-section of the substrate fixing device according to the third embodiment.

[0016] Figure 6 This is a schematic diagram showing a cross-section of the substrate fixing device according to the fourth embodiment.

[0017] Figure 7 This is a schematic diagram showing a cross-section of the substrate fixing device according to the fifth embodiment.

[0018] Figure 8 This is a schematic diagram showing a cross-section of the substrate fixing device according to the sixth embodiment.

[0019] Figure 9 This is a schematic diagram showing a cross-section of the substrate fixing device according to the seventh embodiment.

[0020] Figure 10 This is a schematic diagram showing a cross-section of the substrate fixing device according to the eighth embodiment.

[0021] Figure 11 A modified embodiment of the adsorption electrode structure is shown.

[0022] Figure 12 This is a schematic diagram showing a cross-section of the substrate fixing device according to a variant embodiment. Detailed Implementation

[0023] Hereinafter, embodiments of the electrostatic chuck and substrate fixing device of this disclosure will be described in detail with reference to the accompanying drawings. It should be noted that the disclosed technology is not limited to these embodiments.

[0024] (First Embodiment)

[0025] Figure 1 This is a perspective view showing the structure of the substrate fixing device 100 according to the first embodiment. Figure 1 The substrate fixing device 100 shown has a structure in which an electrostatic chuck 120 is attached to the substrate 110.

[0026] The substrate 110 is a circular component made of metal such as aluminum. The substrate 110 is a base component for fixing the electrostatic chuck 120. The substrate 110 is attached, for example, to a semiconductor manufacturing apparatus, and the substrate holder 100 is used as a semiconductor holding device for holding wafers. It should be noted that, in addition to being attached to a semiconductor manufacturing apparatus, the substrate 110 can also be attached to, for example, an exposure apparatus, a processing apparatus, a bonding apparatus, a measuring apparatus, an inspection apparatus, etc., and the substrate holder 100 can be used as a semiconductor holding device.

[0027] An electrostatic chuck 120 is attached to a base plate 110 and configured to attract target objects such as wafers using electrostatic force. The electrostatic chuck 120 is a circular component with a diameter smaller than that of the base plate 110, and one surface of the electrostatic chuck 120 is attached to the center of the base plate 110. The electrostatic chuck 120 is configured to attach target objects such as wafers to an adsorption surface on the opposite side of the attachment surface to the base plate 110. Specifically, the electrostatic chuck 120 is made of ceramic with adsorption electrodes built into the adsorption surface and is configured to attract target objects to the adsorption surface by electrostatic force when a voltage is applied from the base plate 110 to the adsorption electrodes.

[0028] Figure 2 This is a schematic diagram showing a cross-section of the substrate fixing device 100 according to the first embodiment. Figure 2 The diagram illustrates the route along... Figure 1 The cross-sectional view taken from line II-II in the diagram. (See diagram below.) Figure 2 As shown, the substrate fixing device 100 is constructed by bonding the electrostatic chuck 120 to the base plate 110 via the adhesive layer 200. Hereinafter, for convenience, the direction from the base plate 110 toward the electrostatic chuck 120 will be referred to as the upward direction, and the direction from the electrostatic chuck 120 toward the base plate 110 will be referred to as the downward direction. However, the substrate fixing device 100 can be manufactured and used in any orientation (such as an inverted orientation).

[0029] The base plate 110 is a component with a thickness of 5 mm to 100 mm and is made of a metal such as aluminum. A power supply line 115 extends through the base plate 110. The power supply line 115 is formed, for example, in the shape of a pin, extends through the adhesive layer 200, and connects to the power supply pad 130 of the electrostatic chuck 120. The power supply line 115 contacts the power supply pad 130, thereby supplying power to the wiring 140 in the electrostatic chuck 120. A switch 115a is connected to the power supply line 115. The switch 115a can switch the connection between the power supply line 115 and the positive or negative terminal of the DC power supply 115b, as well as the connection between the power supply line 115 and ground potential.

[0030] Additionally, the base plate 110 is provided with a grounding wire 116 that penetrates the base plate. The grounding wire 116 is switched between a state connected to the ground potential and a state not connected to the ground potential by a switch 116a. The grounding wire 116 is formed, for example, in the shape of a pin, penetrates the adhesive layer 200, and is connected to the grounding electrode 160 of the electrostatic chuck 120. The grounding wire 116 connected to the grounding electrode 160 is connected to the ground potential, so that the grounding electrode 160 is connected to the ground potential.

[0031] The electrostatic chuck 120 has internally energized wiring 140 and is made of, for example, a ceramic plate obtained by firing alumina. The thickness of the electrostatic chuck 120 is, for example, about 1 mm to 20 mm. A cavity 120b is formed at the outer periphery of the lower surface of the electrostatic chuck 120. The cavity 120b is a recess that can accommodate the power supply line 115 of the base plate 110, and the lower surface of the power supply pad 130 is exposed in the cavity 120b. The end of the power supply line 115 contacts the lower surface of the power supply pad 130, thereby supplying power from the base plate 110 to the wiring 140 in the electrostatic chuck 120.

[0032] The upper surface of the electrostatic chuck 120 is an adsorption surface 120a for adsorbing target objects. An adsorption electrode 150 for generating electrostatic force is built into the vicinity of the adsorption surface 120a. A power supply pad 130, in contact with the power supply line 115, is built into the lower surface of the electrostatic chuck 120 on the opposite side of the adsorption surface 120a. The power supply pad 130 and the adsorption electrode 150 are electrically connected to each other via wiring 140 consisting of multiple stacked (laminated) connection pads 141 and conductive portions 142. That is, multiple layers of connection pads 141 are arranged between the power supply pad 130 in contact with the power supply line 115 and the adsorption electrode 150. The power supply pads 130 and connection pads 141, adjacent connection pads 141, and connection pads 141 and adsorption electrodes 150 are connected via conductive portions 142.

[0033] exist Figure 2 In the illustrated configuration, the adsorption electrode 150 is a bipolar electrode, divided into a first electrode 150A and a second electrode 150B. The first electrode 150A is a positive electrode that can be connected to the positive terminal of the DC power supply 115b, and the second electrode 150B is a negative electrode that can be connected to the negative terminal of the DC power supply 115b. Each of the first electrode 150A and the second electrode 150B consists of multiple concentrically arranged semi-circular arc-shaped conductor patterns, arranged inside the electrostatic chuck 120 such that the chord sides of the semi-circles face each other.

[0034] The wiring 140 is arranged in two groups on the left and right sides according to the first electrode 150A and the second electrode 150B of the adsorption electrode 150, and each wiring 140 is formed by stacking two layers of connecting pads 141 between the power supply pad 130 and the adsorption electrode 150.

[0035] The connection pads 141 are formed of a conductor such as tungsten. In addition, the conductive portions 142 are formed by filling the vias formed between the connection pads 141 in adjacent layers with a conductor such as molybdenum.

[0036] A grounding electrode 160 is disposed within the electrostatic chuck 120 between the lower surface of the electrostatic chuck 120 and the adsorption electrode 150. The grounding electrode 160 is made of a metal such as tungsten and has a circular pattern with a diameter of approximately 270 mm to 300 mm and a thickness of approximately 10 μm to 50 μm, and is configured to be connected to a grounding potential. Specifically, a cavity 120c is formed in the center of the lower surface of the electrostatic chuck 120. The cavity 120c is a recess capable of accommodating the end of the grounding wire 116 of the base plate 110, and the lower surface of the grounding electrode 160 is exposed in the cavity 120c. The end of the grounding wire 116, which is connected to the grounding potential, is connected to the lower surface of the grounding electrode 160, thereby connecting the grounding electrode 160 to the grounding potential. For example, when a target object is adsorbed onto the adsorption surface 120a of the electrostatic chuck 120, the power supply line 115 is connected to the positive or negative terminal of the DC power supply 115b via a switch 115a, and the grounding line 116 is disconnected from the ground potential via a switch 116a. Thus, the grounding electrode 160 is disconnected from the ground potential. On the other hand, when the target object is separated from the adsorption surface 120a, the power supply line 115 is connected to the ground potential via a switch 115a, and the grounding line 116 is connected to the ground potential via a switch 116a. Thus, the grounding electrode 160 is connected to the ground potential.

[0037] Wiring 170, formed by stacking multiple connection pads 171 and conductive portions 172, is connected to the ground electrode 160. Wiring 170 extends to the adsorption surface 120a of the electrostatic chuck 120. The ground electrode 160 and the adsorption surface 120a are electrically connected to each other via wiring 170, which consists of stacked multiple connection pads 171 and conductive portions 172. That is, multiple layers of connection pads 171 are arranged between the ground electrode 160, which contacts the ground wire 116, and the adsorption surface 120a. Conductive portions 172 connect the ground electrode 160 and the connection pads 171, adjacent connection pads 171, and the connection pads 171 and the adsorption surface 120a, respectively. The end face of the conductive portion 172 connecting the connection pads 171 and the adsorption surface 120a (i.e., the end face of the wiring 170) is exposed from the adsorption surface 120a.

[0038] exist Figure 2 In the configuration shown, the wiring 170 is arranged in two groups on the left and right sides according to the first electrode 150A and the second electrode 150B of the adsorption electrode 150, and each wiring 170 is formed by stacking two layers of connecting pads 171 between the ground electrode 160 and the adsorption surface 120a.

[0039] The connection pads 171 are formed of a conductor such as tungsten. In addition, the conductive portions 172 are formed by filling the vias formed between the connection pads 171 in adjacent layers with a conductor such as molybdenum.

[0040] Thus, a grounding electrode 160, connectable to a ground potential, is arranged in the electrostatic chuck 120, and a wiring 170 extending to the adsorption surface 120a is connected to the grounding electrode 160. Therefore, when the voltage applied to the adsorption electrode 150 is stopped, the charge remaining on the adsorption surface 120a can escape to the grounding electrode 160 via the wiring 170. That is, since the amount of charge remaining on the adsorption surface 120a is reduced, the adsorption force generated between the adsorption surface 120a and the wafer due to the charge on the adsorption surface 120a can be reduced. As a result, separation of the wafer from the adsorption surface 120a can be facilitated.

[0041] The grounding electrode 160 is positioned in the electrostatic chuck 120 at a distance from the adsorption electrode 150 equal to the distance from the power supply pad 130 to the adsorption electrode 150. This allows the lengths of the power supply line 115 (contacting the lower surface of the power supply pad 130) and the grounding line 116 (contacting the lower surface of the grounding electrode 160) to be identical, simplifying the manufacturing process of the electrostatic chuck 120.

[0042] The end face of the wiring 170 exposed from the adsorption surface 120a of the electrostatic chuck 120 is covered by a metal layer 180. The metal layer 180 is formed by electrolytic plating or chemical plating using a metal such as nickel or a nickel-gold alloy as the material. The adsorption surface 120a of the electrostatic chuck 120 and the metal layer 180 are covered by a barrier film 190. The barrier film 190 is formed, for example, by thermal spraying, sputtering, or CVD (chemical vapor deposition) using a material such as alumina, yttrium oxide, or diamond-like carbon. A protrusion 190a is formed in the barrier film 190 at the location of the metal layer 180, protruding in a direction away from the adsorption surface 120a of the electrostatic chuck 120. After forming the barrier film 190 and polishing its upper surface, the protrusion 190a is formed by sandblasting the area of ​​the barrier film 190 that does not overlap with the metal layer 180. For example, protrusion 190a has a diameter of about 100 μm to 2 mm and a height of about 5 μm to 20 μm, and metal layer 180 has a height of 1 μm to 20 μm. The height of protrusion 190a is the distance from the upper surface of the portion of the insulating film 190 covering the adsorption surface 120a to the upper surface of protrusion 190a covering the metal layer 180.

[0043] In this way, the end face of the wiring 170 exposed from the adsorption surface 120a of the electrostatic chuck 120 is covered by the metal layer 180, and the insulating film 190 forms a protrusion 190a at the location of the metal layer 180, thereby reducing the contact area between the adsorption surface 120a and the wafer. Therefore, the adsorption force generated between the adsorption surface 120a and the wafer due to the charge on the adsorption surface 120a can be further reduced. As a result, the separation of the wafer from the adsorption surface 120a can be further promoted.

[0044] Next, refer to Figure 3 A method for manufacturing the substrate fixing device 100 according to the first embodiment is described. Figure 3 This is a flowchart illustrating a method for manufacturing the substrate fixing device 100 according to the first embodiment.

[0045] First, multiple green sheets are prepared to form the electrostatic chuck 120 (step S101). Specifically, the green sheets are prepared by drying a slurry mixture obtained by mixing, for example, alumina and a specified auxiliary agent. The green sheets are, for example, square sheets with a length and width of 500 mm × 500 mm and a thickness of 0.7 mm.

[0046] Each green wafer is formed with conductive portions 142 and 172 for connecting pads 141 and 171 of adjacent layers (step S102). Specifically, through-holes are formed at the overlapping locations of the connecting pads 141 and 171 of adjacent layers, and the through-holes are filled with a conductor such as molybdenum to form conductive portions 142 and 172. It should be noted that, similar to the through-holes, cavities 120b and 120c are also formed as through-holes through the green wafer. That is, the through-holes of multiple stacked green wafers are connected to form openings, thereby forming cavities 120b and 120c.

[0047] Patterns of connection pads 141 and 171 are printed on the green wafer on which conductive portions 142 and 172 are formed (step S103). That is, connection pads 141 and 171 are formed by printing a metal paste such as tungsten on the surface of the green wafer.

[0048] Additionally, an adsorption electrode 150 is formed on a green sheet stacked near the adsorption surface 120a of the electrostatic chuck 120 (step S104). Furthermore, a ground electrode 160 is formed on a green sheet stacked between the lower surface of the electrostatic chuck 120 and the adsorption electrode 150 on the opposite side (step S105).

[0049] Green wafers having connecting pads 141 and 171, adsorption electrodes 150 and ground electrodes 160 formed thereon are stacked sequentially, wherein the connecting pads 141 and 171, adsorption electrodes 150 and ground electrodes 160 of adjacent layers are connected by conductive portions 142 and 172 (step S106). Thus, two layers of connecting pads 141 are stacked to form wiring 140 between the power supply pad 130 and the adsorption electrode 150, and two layers of connecting pads 171 are stacked to form wiring 170 between the ground electrode 160 and the adsorption surface 120a. The end faces of the wiring 170 are exposed on the adsorption surface 120a. Then, the stack of green wafers is cut into a circle according to the shape of the substrate 110 (step S107).

[0050] The stacked body, cut into a circle, is fired in a firing furnace to become ceramic (step S108). The ceramic disc obtained by firing becomes an electrostatic chuck 120. Then, a metal layer 180 is formed on the end face of the wiring 170 exposed from the adsorption surface 120a of the electrostatic chuck 120 (step S109). That is, a metal layer 180 made of, for example, nickel or a nickel-gold alloy is formed on the end face of the wiring 170 exposed from the adsorption surface 120a by electrolytic plating or chemical plating.

[0051] After the metal layer 180 is formed, an insulating film 190 is formed on the adsorption surface 120a of the electrostatic chuck 120 and on the surface of the metal layer 180 (step S110). That is, an insulating film 190 made of materials such as alumina, yttrium oxide, or diamond-like carbon is formed on the adsorption surface 120a of the electrostatic chuck 120 and on the surface of the metal layer 180 by thermal spraying, sputtering, or CVD.

[0052] Then, the electrostatic chuck 120 is bonded to the metal base plate 110 via the adhesive layer 200 (step S111). To form the adhesive layer 200, a bonding material is used, for example. Thus, the substrate fixing device 100 is completed.

[0053] As described above, the electrostatic chuck according to the first embodiment (e.g., electrostatic chuck 120) includes a ceramic plate, an adsorption electrode (e.g., adsorption electrode 150), a ground electrode (e.g., ground electrode 160), and wiring (e.g., wiring 170). The adsorption electrode is embedded near one surface of the ceramic plate (e.g., adsorption surface 120a). The ground electrode is disposed in the ceramic plate between the other surface of the ceramic plate and the adsorption electrode, and can be connected to a ground potential. The wiring is connected to the ground electrode in the ceramic plate and extends to one surface of the ceramic plate. Thus, the electrostatic chuck according to the first embodiment can facilitate the separation of substrates (e.g., wafers).

[0054] Additionally, the electrostatic chuck may also include a metal layer (e.g., metal layer 180) and a barrier film (e.g., barrier film 190). The metal layer may be configured to cover the end face of the wiring exposed from one surface of the ceramic plate. The barrier film may be configured to cover one surface of the ceramic plate and the metal layer, and a protrusion (e.g., protrusion 190a) may be formed at the location of the metal layer. Thus, the electrostatic chuck according to the first embodiment can further facilitate the separation of the substrate.

[0055] Additionally, the electrostatic chuck may include a power supply pad (e.g., power supply pad 130) embedded near another surface of the ceramic plate, electrically connected to the adsorption electrode via wiring (e.g., wiring 140), and connected to a power supply line (e.g., power supply line 115). A ground electrode may be arranged in the ceramic plate at a location where the distance from the ground electrode to the adsorption electrode is the same as the distance from the power supply pad to the adsorption electrode. Thus, the manufacturing process of the electrostatic chuck according to the first embodiment can be simplified.

[0056] Furthermore, the grounding electrode can be connected to a grounding wire (e.g., grounding wire 116), which switches between being connected to a grounding potential and not connected to a grounding potential. Thus, according to the electrostatic chuck of the first embodiment, the grounding electrode can be connected to a grounding potential when, for example, the substrate is separated from the adsorption surface.

[0057] (Second Embodiment)

[0058] The second embodiment involves a change in the arrangement of the grounding electrode 160 of the first embodiment.

[0059] Figure 4 This is a schematic diagram showing a cross-section of the substrate fixing device 100 according to the second embodiment. Figure 4 In, with Figure 2 The same parts are indicated by the same reference numerals. Figure 4 The grounding electrode 160 shown is arranged in the electrostatic chuck 120 at a position where the distance between the grounding electrode 160 and the adsorption electrode 150 is closer than the distance between the power supply pad 130 and the adsorption electrode 150.

[0060] exist Figure 4 In the illustrated configuration, the ground electrode 160 is positioned such that the distance between the ground electrode 160 and the adsorption electrode 150 is the same as the distance between the closest layer of the bonding pad 141 to the adsorption electrode 150. The ground electrode 160 is positioned close to the adsorption electrode 150, thereby shortening the wiring 170 used to connect the ground electrode 160 and the adsorption surface 120a. That is, in Figure 4 In the configuration shown, wiring 170 does not have connection pads 171 (see...) Figure 2It consists only of a conductive portion 172 that connects the ground electrode 160 and the adsorption surface 120a, and the wiring 170 is short in length.

[0061] In this way, the ground electrode 160 is positioned closer to the adsorption electrode 150 than the power supply pad 130 is to the adsorption electrode, thereby shortening the length of the wiring 170 used to connect the ground electrode 160 and the adsorption surface 120a. Therefore, when voltage is stopped being applied to the adsorption electrode 150, the charge remaining on the adsorption surface 120a can quickly escape to the ground electrode 160 via the short wiring 170. Thus, the electrostatic chuck 120 according to the second embodiment can shorten the time from when voltage is stopped being applied to the adsorption electrode 150 until the substrate (e.g., a wafer) is separated.

[0062] (Third Embodiment)

[0063] The third embodiment involves a change in the structure of the barrier membrane 190 of the first embodiment.

[0064] Figure 5 This is a schematic diagram showing a cross-section of the substrate fixing device 100 according to the third embodiment. Figure 5 In, with Figure 2 The same parts are indicated by the same reference numerals. Figure 5 The barrier film 190 shown only covers the metal layer 180, and a protrusion 190a is formed at the location of the metal layer 180, protruding in a direction away from the adsorption surface 120a of the electrostatic chuck 120. For example, the protrusion 190a is formed by dripping alumina paste onto the location of the metal layer 180, firing the alumina paste, and polishing the upper surface of the obtained barrier film 190.

[0065] Thus, the barrier film 190 only covers the metal layer 180, and protrusions 190a are formed at the locations of the metal layer 180, thereby reducing the contact area between the adsorption surface 120a and the wafer. Therefore, the adsorption force generated between the adsorption surface 120a and the wafer due to the charge on the adsorption surface 120a can be further reduced. Therefore, the electrostatic chuck 120 according to the third embodiment can further facilitate the separation of the substrate (e.g., the wafer) from the adsorption surface 120a. Furthermore, the electrostatic chuck 120 according to the third embodiment, since the coverage area of ​​the barrier film 190 can be reduced, can reduce the amount of material used in the barrier film 190 compared to the barrier film 190 of the first embodiment.

[0066] (Fourth Embodiment)

[0067] The fourth embodiment involves a change in the structure of the insulating film 190 and the adsorption surface 120a of the electrostatic chuck 120 of the first embodiment.

[0068] Figure 6 This is a schematic diagram showing a cross-section of the substrate fixing device 100 according to the fourth embodiment. Figure 6 In, with Figure 2 The same parts are indicated by the same reference numerals. Figure 6 In the configuration shown, the wiring 170 is arranged in two groups on the left and right sides according to the first electrode 150A and the second electrode 150B of the adsorption electrode 150. The end faces of the two wirings 170 are exposed from the adsorption surface 120a of the electrostatic chuck 120. The metal layer 180 is formed at each of the two locations on the adsorption surface 120a where the end faces of the two wirings 170 are exposed.

[0069] Figure 6 The barrier film 190 shown is configured to cover only the metal layer 180 at each of the two locations where the end faces of the two exposed wirings 170 are on the adsorption surface 120a. Additionally, a step 120d is formed on the adsorption surface 120a and around the protrusion 190a formed by the barrier film 190. The step 120d is formed by forming the barrier film 190 covering the adsorption surface 120a and the surface of the metal layer 180 of the electrostatic chuck 120, and then sandblasting the inside of the electrostatic chuck 120 to form the protrusion 190a.

[0070] In this way, the barrier film 190 only covers the metal layer 180, and the step 120d is formed on the adsorption surface 120a and around the protrusion 190a formed by the barrier film 190, thereby reducing the possibility of contact between the adsorption surface 120a and the wafer. As a result, the electrostatic chuck 120 according to the fourth embodiment can suppress the generation of particles due to contact between the adsorption surface 120a and the wafer.

[0071] (Fifth Embodiment)

[0072] The fifth embodiment relates to a change in the structure of the barrier membrane 190 of the first embodiment.

[0073] Figure 7 This is a schematic diagram showing a cross-section of the substrate fixing device 100 according to the fifth embodiment. Figure 7 In, with Figure 2 The same parts are indicated by the same reference numerals. Figure 7 In the configuration shown, the wiring 170 is arranged in two groups on the left and right sides according to the first electrode 150A and the second electrode 150B of the adsorption electrode 150. The end faces of the two wirings 170 are exposed from the adsorption surface 120a of the electrostatic chuck 120. Furthermore, no metal layer 180 is formed (see [reference]). Figure 2 ).

[0074] Figure 7The barrier film 190 shown is formed at each of two locations on the end faces of the two wires 170 exposed from the adsorption surface 120a. The barrier film 190 is configured to cover only the end faces of the two wires 170 exposed from the adsorption surface 120a, and a protrusion 190a protruding away from the adsorption surface 120a of the electrostatic chuck 120 is formed at the location of each end face of the wire 170. For example, the protrusion 190a is formed by dripping alumina paste onto the location of each end face of the wire 170, firing the alumina paste, and polishing the upper surface of the resulting barrier film 190.

[0075] Thus, the insulating film 190 only covers the end face of the wiring 170, and a protrusion 190a is formed at the end face of the wiring 170, thereby reducing the contact area between the adsorption surface 120a and the wafer. Therefore, the adsorption force generated between the adsorption surface 120a and the wafer due to the charge on the adsorption surface 120a can be further reduced. Therefore, the electrostatic chuck 120 according to the fifth embodiment can further facilitate the separation of the substrate (e.g., the wafer) from the adsorption surface 120a. Furthermore, the electrostatic chuck 120 according to the fifth embodiment can omit the metal layer 180 formation process, which simplifies the manufacturing process of the electrostatic chuck 120.

[0076] (Sixth Embodiment)

[0077] The sixth embodiment relates to a change in the structure of the barrier membrane 190 of the first embodiment.

[0078] Figure 8 This is a schematic diagram showing a cross-section of the substrate fixing device 100 according to the sixth embodiment. Figure 8 In, with Figure 2 The same parts are indicated by the same reference numerals. Figure 8 In the structure shown, no metal layer 180 is formed (see...). Figure 2 ).

[0079] Figure 8 The barrier film 190 shown is configured to cover the adsorption surface 120a of the electrostatic chuck 120 and the end face of the wiring 170 exposed from the adsorption surface 120a, and a protrusion 190a is formed at the end face of the wiring 170. After forming the barrier film 190 and polishing its upper surface, the protrusion 190a is formed by sandblasting in the area of ​​the barrier film 190 that does not overlap with the end face of the wiring 170. It should be noted that by sandblasting the protrusion towards the inside of the electrostatic chuck 120, a step reaching the inside of the electrostatic chuck 120 can be formed around the protrusion 190a.

[0080] Thus, the end face of the wiring 170 exposed from the adsorption surface 120a is covered by the insulating film 190, and the insulating film 190 forms a protrusion 190a at the position of the end face of the wiring 170, thereby reducing the contact area between the adsorption surface 120a and the wafer. Therefore, the adsorption force generated between the adsorption surface 120a and the wafer due to the charge on the adsorption surface 120a can be further reduced. Therefore, the electrostatic chuck 120 according to the sixth embodiment can further promote the separation of the wafer from the adsorption surface 120a. In addition, the process of forming the metal layer 180 can be omitted in the electrostatic chuck 120 according to the sixth embodiment, which simplifies the manufacturing process of the electrostatic chuck 120.

[0081] (Seventh Embodiment)

[0082] The seventh embodiment involves a change in the structure of the metal layer 180 and the insulating film 190 of the first embodiment.

[0083] Figure 9 This is a schematic diagram showing a cross-section of the substrate fixing device 100 according to the seventh embodiment. Figure 9 In the image, the area near the adsorption surface 120a of the electrostatic chuck 120 is shown magnified. Figure 9 In, with Figure 2 The same parts are indicated by the same reference numerals.

[0084] Figure 9 The metal layer 180 shown has a two-layer structure. Specifically, the metal layer 180 has a first metal layer 181 and a second metal layer 182.

[0085] The first metal layer 181 is configured to cover the end face of the wiring 170 exposed from the adsorption surface 120a of the electrostatic chuck 120. The first metal layer 181 is formed by electrolytic plating or chemical plating using a metal such as nickel or a nickel-gold alloy as the material.

[0086] A second metal layer 182 is stacked on top of a first metal layer 181, and the upper surface of the second metal layer 182 protrudes in a spherical shape. The second metal layer 182 is formed by attaching solder paste, solder plating, or solder balls to the upper surface of the first metal layer 181. The second metal layer 182 is melted and solidified by undergoing a reflow process and protrudes upward in a spherical shape.

[0087] It should be noted that the second metal layer 182 can also be formed by applying silver paste to the upper surface of the first metal layer 181. In this case, the second metal layer 182 is heated and cured by undergoing a thermosetting process and protrudes upward in a spherical shape.

[0088] The insulating film 190, configured to cover a metal layer 180 having a two-layer structure, has a flat surface at the top of the protrusion 190a corresponding to the position of the second metal layer 182. The flat surface of the insulating film 190 is formed by polishing.

[0089] Thus, the metal layer 180 covered by the insulating film 190 has a two-layer structure, and the upper second metal layer 182 protrudes upward in a spherical shape, thereby allowing the protrusions 190a of the insulating film 190 to be formed into a tapered shape with the width decreasing towards the top. Therefore, the contact area between the protrusions 190a and the wafer can be reduced. Consequently, the electrostatic chuck 120 according to the seventh embodiment can suppress the generation of particles due to contact between the surface of the protrusions 190a and the wafer.

[0090] Furthermore, since the insulating film 190 has a flat surface at the top of the protrusion 190a corresponding to the position of the second metal layer 182, the contact area between the protrusion 190a and the wafer can be further reduced. Therefore, the electrostatic chuck 120 according to the seventh embodiment can further suppress the generation of particles due to the contact between the surface of the protrusion 190a and the wafer.

[0091] (Eighth Embodiment)

[0092] The eighth embodiment involves a change in the structure of the metal layer 180 and the insulating film 190 of the first embodiment.

[0093] Figure 10 This is a schematic diagram showing a cross-section of the substrate fixing device 100 according to the eighth embodiment. Figure 10 In the image, the area near the adsorption surface 120a of the electrostatic chuck 190 is shown magnified. Figure 10 In, with Figure 2 The same parts are indicated by the same reference numerals.

[0094] Figure 10 The metal layer 180 shown has a two-layer structure. Specifically, the metal layer 180 has a first metal layer 181 and a second metal layer 183.

[0095] The first metal layer 181 is configured to cover the end face of the wiring 170 exposed from the adsorption surface 120a of the electrostatic chuck 120. The first metal layer 181 is formed by electrolytic plating or chemical plating using a metal such as nickel or a nickel-gold alloy as the material.

[0096] The second metal layer 183 is stacked on the first metal layer 181 and has a width smaller than that of the first metal layer 181. For example, when forming the second metal layer 183, a protective strip is attached to the upper surface of the first metal layer 181, and the protective strip is patterned by laser processing to form openings in the protective strip with a width smaller than that of the first metal layer 181. Then, using the protective strip with the openings as a plating mask, the second metal layer 183, such as nickel or gold, is formed by electrolytic plating or chemical plating. After the second metal layer 183 is formed, the protective strip is peeled off.

[0097] It should be noted that a photosensitive dry film can be used instead of a protective strip when forming the second metal layer 183. In this case, for example, a photosensitive dry film is laminated onto the upper surface of the first metal layer 181, and the dry film is patterned by photolithography to form a resist layer with openings narrower than the width of the first metal layer 181. Then, using the resist layer as a plating mask, a second metal layer 183 of nickel, gold, etc., is formed by electrolytic plating or chemical plating. After forming the second metal layer 183, the resist layer is removed by an alkaline stripping solution. Alternatively, the second metal layer 183 can also be formed directly on the upper surface of the first metal layer 181 using a wire bump method.

[0098] The insulating film 190, configured to cover a metal layer 180 having a two-layer structure, has a flat surface at the top of the protrusion 190a corresponding to the position of the second metal layer 183. The flat surface of the insulating film 190 is formed by polishing.

[0099] Thus, the metal layer 180 covered by the insulating film 190 has a two-layer structure, and the width of the upper second metal layer 183 is smaller than the width of the first metal layer 181. Therefore, the protrusions 190a of the insulating film 190 can be formed into a tapered shape with the width decreasing towards the top. This reduces the contact area between the protrusions 190a and the wafer. Consequently, the electrostatic chuck 120 according to the eighth embodiment can suppress the generation of particles due to contact between the surface of the protrusions 190a and the wafer.

[0100] Furthermore, since the insulating film 190 has a flat surface at the top of the protrusion 190a corresponding to the position of the second metal layer 183, the contact area between the protrusion 190a and the wafer can be further reduced. Thus, the electrostatic chuck 120 according to the eighth embodiment can further suppress the generation of particles due to the contact between the surface of the protrusion 190a and the wafer.

[0101] (other)

[0102] In each of the above embodiments, the adsorption electrode 150 is a bipolar electrode, but the adsorption electrode 150 can also be a unipolar electrode. For example, as... Figure 11 As shown, the adsorption electrode 150 can be formed from an unseparated disk-shaped conductor pattern. Figure 11 A modified embodiment of the structure of the adsorption electrode 150 is shown. Figure 11 In the configuration shown, the power supply pads 130 and wiring 140 are arranged as a set for attracting the electrodes 150.

[0103] Even when the adsorption electrode 150 is a unipolar electrode, since the ground electrode 160 is arranged in the electrostatic chuck 120 and the wiring 170 is connected to the ground electrode 160, the charge on the adsorption surface 120a can also escape to the ground electrode 160 through the wiring 170.

[0104] Furthermore, in each of the above embodiments, an insulating film 190 covering the metal layer 180 or an insulating film 190 covering the end face of the wiring 170 is formed. However, the insulating film 190 covering the metal layer 180 and the insulating film 190 covering the end face of the wiring 170 may also be mixed.

[0105] In addition, as Figure 6 The structural changes of the barrier membrane 190 shown in the fourth embodiment are, for example, as Figure 12 As shown, an insulating film 190 can be formed at each of two locations on the adsorption surface 120a where the two end faces of the wiring 170 are exposed. The insulating layer can be configured to cover only the end faces of the two wirings 170 without covering the metal layer 180.

Claims

1. An electrostatic chuck, comprising: Ceramic slab; An adsorption electrode is embedded near one surface of the ceramic plate; A grounding electrode is disposed in the ceramic plate between the other surface of the ceramic plate and the adsorption electrode, extending within the ceramic plate to a position where the grounding electrode overlaps with the adsorption electrode when the electrostatic chuck is viewed from above, and is connectable to a ground potential; Wiring is provided that connects to the ground electrode in the ceramic plate and extends to one surface of the ceramic plate; A metal layer configured to cover the end face of the wiring exposed from one surface of the ceramic plate; as well as An insulating membrane is configured to cover one surface of the ceramic plate and the metal layer, or only the metal layer, and to form protrusions at the location of the metal layer.

2. The electrostatic chuck according to claim 1, wherein, The metal layer includes: A first metal layer, configured to cover the end face of the wiring exposed from one surface of the ceramic plate, and A second metal layer is stacked on top of the first metal layer, and the surface of the second metal layer away from the first metal layer protrudes in a spherical shape.

3. The electrostatic chuck according to claim 1, wherein, The metal layer includes: A first metal layer, configured to cover the end face of the wiring exposed from one surface of the ceramic plate, and A second metal layer is stacked on top of the first metal layer and has a width smaller than that of the first metal layer.

4. The electrostatic chuck according to claim 2 or 3, wherein, The insulating membrane has a flat surface on the top of the protrusion corresponding to the position of the second metal layer.

5. The electrostatic chuck according to any one of claims 1 to 3, comprising: Multiple wiring, The metal layer is formed at each of a plurality of locations on one surface of the ceramic plate where the end faces of the plurality of wirings are exposed. The insulating membrane is configured to cover the metal layer only at each of the plurality of locations, and One surface of the ceramic plate has steps formed around the protrusions formed by the insulating membrane.

6. The electrostatic chuck according to claim 1, wherein, The grounding electrode is connected to a grounding wire, which switches between being connected to the grounding potential and not being connected to the grounding potential.

7. An electrostatic chuck, comprising: Ceramic slab; An adsorption electrode is embedded near one surface of the ceramic plate; A grounding electrode is disposed in the ceramic plate between the other surface of the ceramic plate and the adsorption electrode, extending within the ceramic plate to a position where the grounding electrode overlaps with the adsorption electrode when the electrostatic chuck is viewed from above, and is connectable to a ground potential; Wiring is provided that connects to the ground electrode in the ceramic plate and extends to one surface of the ceramic plate; as well as An insulating membrane is configured to cover the one surface of the ceramic plate and the end face of the wiring exposed from the one surface of the ceramic plate, or to cover only the end face of the wiring exposed from the one surface of the ceramic plate, and to form a protrusion at the location of the end face of the wiring.

8. The electrostatic chuck according to claim 7, comprising: Multiple wiring, The insulating film is formed at each of a plurality of locations on one surface of the ceramic plate where the end faces of the plurality of wirings are exposed, and is configured to cover only the end faces of the plurality of wirings. One surface of the ceramic plate has steps formed around the protrusions formed by the insulating membrane.

9. An electrostatic chuck, comprising: Ceramic slab; An adsorption electrode is embedded near one surface of the ceramic plate; A grounding electrode is disposed in the ceramic plate between the other surface of the ceramic plate and the adsorption electrode, extending within the ceramic plate to a position where the grounding electrode overlaps with the adsorption electrode when the electrostatic chuck is viewed from above, and is connectable to a ground potential; Wiring is provided that connects to the ground electrode in the ceramic plate and extends to one surface of the ceramic plate; as well as A power supply pad, which is embedded near the other surface of the ceramic plate, is electrically connected to the adsorption electrode via wiring and is also connected to the power supply line. The grounding electrode is arranged in the ceramic plate at the following position: at this position, the distance between the grounding electrode and the adsorption electrode is the same as the distance between the power supply pad and the adsorption electrode.

10. An electrostatic chuck, comprising: Ceramic slab; An adsorption electrode is embedded near one surface of the ceramic plate; A grounding electrode is disposed in the ceramic plate between the other surface of the ceramic plate and the adsorption electrode, extending within the ceramic plate to a position where the grounding electrode overlaps with the adsorption electrode when the electrostatic chuck is viewed from above, and is connectable to a ground potential; Wiring is provided that connects to the ground electrode in the ceramic plate and extends to one surface of the ceramic plate; as well as A power supply pad, which is embedded near the other surface of the ceramic plate, is electrically connected to the adsorption electrode via wiring and is also connected to the power supply line. The grounding electrode is arranged in the ceramic plate at a position where the distance between the grounding electrode and the adsorption electrode is closer than the distance between the power supply pad and the adsorption electrode.

11. A substrate fixing device, comprising: Base plate; as well as An electrostatic chuck is fixed to the base plate and configured to attract the substrate by electrostatic force. The electrostatic chuck includes: Ceramic slab; An adsorption electrode is embedded in the ceramic plate near one surface of the substrate. A grounding electrode is disposed in the ceramic plate between the other surface of the ceramic plate and the adsorption electrode, extending within the ceramic plate to a position where the grounding electrode overlaps with the adsorption electrode when the electrostatic chuck is viewed from above, and is connectable to a ground potential; Wiring that connects to the ground electrode in the ceramic plate and extends to one surface of the ceramic plate; A metal layer configured to cover the end face of the wiring exposed from one surface of the ceramic plate; and An insulating membrane is configured to cover one surface of the ceramic plate and the metal layer, or only the metal layer, and to form protrusions at the location of the metal layer.

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