Substrate fixing device, electrostatic chuck and method of manufacturing electrostatic chuck

Abstract

A substrate fixing device comprises a base plate; and an electrostatic chuck fixed to the base plate and configured to adsorb a substrate by electrostatic force. The electrostatic chuck comprises: a ceramic layer formed of ceramic and configured to adsorb a substrate while the ceramic layer is in contact with the substrate; a first heater pattern disposed on the ceramic layer and configured to generate heat; an insulating resin layer disposed on the first heater pattern and covering the first heater pattern; a second heater pattern disposed on the insulating resin layer and configured to generate heat; and a conductive member penetrating the insulating resin layer such that one end of the conductive member contacts the surface of the first heater pattern and the other end of the conductive member contacts the surface of the second heater pattern.

Description

Technology Field

[0001] The present invention relates to a substrate fixing device, an electrostatic chuck, and a method for manufacturing an electrostatic chuck. Background Technology

[0002] An electrostatic chuck (ESC) is typically installed in a substrate fixing device that adsorbs and holds a wafer, for example, to manufacture semiconductor components. The electrostatic chuck is constructed using a ceramic plate with embedded electrodes. The substrate fixing device has a structure in which the electrostatic chuck is fixed to a base plate. When voltage is applied to the electrodes embedded in the ceramic plate, the wafer is adsorbed to the electrostatic chuck using electrostatic force. Since the wafer is adsorbed to the electrostatic chuck and held by the electrostatic chuck, processes such as microfabrication and etching on the wafer can be performed efficiently.

[0003] Such electrostatic chucks can have a temperature control function to control the temperature of the wafer. Specifically, for example, a heater electrode can be formed by screen printing a metal paste, such as tungsten, so that the heater electrode can be fired simultaneously when forming a ceramic plate. In addition, a technique has been devised to form an external heater electrode by etching a rolled metal foil on an insulating resin using photolithography to obtain high thermal uniformity on the wafer mounting surface.

[0004] As an electrostatic chuck utilizing an external heater electrode, the electrode chuck was examined as follows. In the electrostatic chuck, the heater electrode is divided into two layers of heater electrodes and deposited on a ceramic plate, and the two layers of heater electrodes are connected through vias. Dividing the heater electrode into two layers of heater electrodes can improve the degree of freedom for designing the heater wiring, and can further improve the thermal uniformity of the wafer mounting surface by placing the heater electrodes in mutually complementary positions in each layer (see, for example, JP-A-2016-100474, JP-A-2018-026427, and JP-A-2001-028036).

[0005] However, when two layers of external heater electrodes are provided in the electrostatic chuck, a step of forming vias to connect the layers of heater electrodes to each other is required. Consequently, there is a problem of reduced manufacturing efficiency of the electrostatic chuck. Specifically, to form vias, via holes are formed in the insulating resin between the two layers of heater electrodes using, for example, a laser, and the via holes are filled with metal paste. The above-described steps are performed to form a single via. Therefore, as the number of vias increases, it is necessary to repeat the process of forming via holes and filling the via holes with metal paste, which reduces the manufacturing efficiency of the electrostatic chuck.

[0006] A specific embodiment provides a substrate fixing device. The substrate fixing device comprises: a base plate; and an electrostatic chuck fixed to the base plate and configured to adsorb a substrate by electrostatic force. The electrostatic chuck comprises: a ceramic layer formed of ceramic, wherein the ceramic layer is configured to adsorb the substrate while in contact with the substrate; a first heater pattern disposed on the ceramic layer and configured to generate heat; an insulating resin layer disposed on the first heater pattern to cover the first heater pattern; a second heater pattern disposed on the insulating resin layer and configured to generate heat; and the conductive member penetrating the insulating resin layer such that one end of the conductive member contacts the surface of the first heater pattern and the other end contacts the surface of the second heater pattern.

[0007] A specific embodiment provides an electrostatic chuck. The electrostatic chuck comprises: a ceramic layer formed of ceramic and configured to adsorb an object; a first heater pattern disposed on the ceramic layer and configured to generate heat; an insulating resin layer disposed on the first heater pattern to cover the first heater pattern; a second heater pattern disposed on the insulating resin layer and configured to generate heat; and a conductive member penetrating the insulating resin layer such that one end of the conductive member contacts the surface of the first heater pattern and the other end of the conductive member contacts the surface of the second heater pattern.

[0008] A specific embodiment provides a method for manufacturing an electrostatic chuck. The method comprises the steps of: forming a ceramic layer comprising an electrode and a ceramic surrounding the electrode; forming a first heater pattern on the ceramic layer ― the first heater pattern is configured to generate heat ―; placing a conductive member on the surface of the first heater pattern; providing an insulating resin layer on the ceramic layer to cover the conductive member and the first heater pattern ― a metal layer is formed on one surface of the insulating resin layer ―; and patterning the metal layer to form a second heater pattern, wherein the conductive member penetrates the insulating resin layer so as to come into contact with the metal layer in the step of providing the insulating resin layer. Brief explanation of the drawing

[0009] FIG. 1 is a perspective view showing the configuration of a substrate fixing device according to an embodiment. FIG. 2 is a schematic diagram illustrating a cross-section of a substrate fixing device according to an embodiment. FIG. 3 is a flowchart showing a method for manufacturing a substrate fixing device according to an embodiment. FIG. 4 is a drawing showing a specific example of the ceramic layer formation step. FIG. 5 is a drawing showing a specific example of the first insulating resin layer deposition step. FIG. 6 is a drawing showing a specific example of the first heater pattern forming step. FIG. 7 is a drawing showing a specific example of the conductive member placement step. FIG. 8 is a drawing showing a specific example of the second insulating resin layer deposition step. FIG. 9 is a drawing showing a specific example of the second heater pattern forming step. FIG. 10 is a drawing showing a specific example of the first heater patterns. FIG. 11 is a drawing showing specific examples of second heater patterns. FIG. 12 is a drawing showing a specific example of the third insulating resin layer deposition step. FIG. 13 is a drawing showing a specific example of the opening formation step. Specific details for implementing the invention

[0010] Hereinafter, embodiments of the substrate fixing device, electrostatic chuck, and method for manufacturing the electrostatic chuck disclosed by the present application will be described in detail with reference to the drawings. Furthermore, the present disclosure is not limited by the embodiments.

[0011] FIG. 1 is a perspective view showing the configuration of a substrate fixing device (100) according to one embodiment. The substrate fixing device (100) shown in FIG. 1 has a structure in which an electrostatic chuck (120) is adhesively bonded to a base plate (110).

[0012] The base plate (110) is a circular member made of a metal such as aluminum. The base plate (110) is a base material to which the electrostatic chuck (120) is fixed. The base plate (110) is attached, for example, to a semiconductor manufacturing device, and enables the substrate fixing device (100) to function as a semiconductor holding device for holding a wafer.

[0013] The electrostatic chuck (120) controls the temperature of an object, such as a wafer, by adsorbing it using electrostatic force. That is, the electrostatic chuck (120) is formed by providing a ceramic layer for adsorbing the object and a heater layer for heating the object. The electrostatic chuck (120), which has a smaller diameter than the base plate (110), is fixed to the center of the base plate (110). In this case, the heater layer of the electrostatic chuck (120) is bonded to the base plate (110), thereby fixing the electrostatic chuck (120) to the base plate (110). A ceramic layer is provided on the upper surface of the heater layer, so that the adsorption surface of the ceramic layer for adsorbing the object is exposed.

[0014] FIG. 2 is a schematic diagram showing a cross-section along line II of FIG. 1. As shown in FIG. 2, the substrate fixing device (100) has a configuration in which an electrostatic chuck (120) is adhesively bonded to a base plate (110).

[0015] The base plate (110) is a member made of metal and having cooling water channels (111) provided inside as cooling water channels. For example, the thickness of the base plate (110) is about 20 mm to 50 mm. The base plate (110) is configured to cool the electrostatic chuck (120) by cooling water flowing into the cooling water channels (111) from outside the substrate fixing device (100). As a result of cooling the electrostatic chuck (120), an object such as a wafer adsorbed to the electrostatic chuck (120) is cooled.

[0016] Additionally, the base plate (110) may have cooling gas channels provided as cooling gas channels instead of cooling water channels (111). That is, the base plate (110) has a cooling gas passage through which a refrigerant, such as cooling water or cooling gas, passes.

[0017] The electrostatic chuck (120) has a ceramic layer (130), a first insulating resin layer (140), a second insulating resin layer (150), and a third insulating resin layer (160), and the third insulating resin layer (160) is adhesively bonded to a base plate (110).

[0018] The ceramic layer (130) is composed of a ceramic (132) having a conductive electrode (131) provided inside. For example, the thickness of the ceramic layer (130) is about 4.5 mm. The ceramic (132) is obtained by firing green sheets manufactured using, for example, aluminum oxide. Due to the electrostatic force generated by the voltage applied to the electrodes (131) of the ceramic layer (130), the ceramic layer (130) comes into contact with and adsorbs an object such as a substrate. That is, in FIG. 2, the upper surface of the ceramic layer (130) functions as an adsorption surface that contacts an object, and when voltage is applied to the electrode (131), the object is adsorbed to the adsorption surface.

[0019] The first insulating resin layer (140) is formed on the ceramic layer (130) and is a layer made of an insulating resin having high heat resistance and thermal conductivity, such as epoxy resin or bismaleimide-triazine resin. The thickness of the first insulating resin layer (140) is, for example, about 40 μm to 100 μm. The first heater patterns (141) are formed on one side (the lower side in FIG. 2) opposite to the ceramic layer (130) of the first insulating resin layer (140).

[0020] The first heater patterns (141) are electrodes made of an alloy such as CN49 (constantan) (Cu-Ni-Mn-Fe alloy), geranine (Cu-Mn-Sn alloy), or manganin (Cu-Mn-Ni alloy). The first heater patterns (141) generate heat when voltage is applied. The thickness of each first heater pattern (141) is, for example, about 25 µm to 50 µm, and falls within the range of 15 µm to 200 µm.

[0021] A second insulating resin layer (150) is formed to cover the first heater patterns (141) on the first insulating resin layer (140). The second insulating resin layer (150) is a layer made of an insulating resin with high heat resistance and thermal conductivity, such as epoxy resin or bismaleimide-triazine resin, similar to the first insulating resin layer (140). The second insulating resin layer (150) is thicker than the first insulating resin layer (140), for example, with a thickness of about 40 μm to 300 μm. The second heater patterns (151) are formed on one side (the bottom side in FIG. 2) of the second insulating resin layer (150) opposite to the first insulating resin layer (140).

[0022] The second heater patterns (151) are electrodes made of an alloy such as CN49 (constantan) (Cu-Ni-Mn-Fe alloy), geranine (Cu-Mn-Sn alloy), or manganin (Cu-Mn-Ni alloy). The second heater patterns (151) generate heat when voltage is applied. The thickness of each second heater pattern (151) is, for example, about 25 µm to 50 µm, and falls within the range of 15 µm to 200 µm. The second heater patterns (151) are electrically connected to the first heater patterns (141) through conductive members (170) described later.

[0023] A third insulating resin layer (160) is formed to cover the second heater patterns (151) on the second insulating resin layer (150). The third insulating resin layer (160), like the first insulating resin layer (140) and the second insulating resin layer (150), is a layer made of an insulating resin with high heat resistance and thermal conductivity, such as epoxy resin or bismaleimide-triazine resin. The thickness of the third insulating resin layer (160) is, for example, about 40 μm to 300 μm. Power supply sections (161) are formed inside the third insulating resin layer (160) to supply power from the base plate (110) to the second heater patterns (151).

[0024] The power supply sections (161) are conductive members that electrically connect the base plate (110) and the second heater patterns (151). The power supply sections (161) apply voltage supplied from the base plate (110) to the second heater patterns (151).

[0025] Conductive members (170) are embedded in the second insulating resin layer (150). Each conductive member (170) is a conductive member having one end in contact with one surface of a corresponding first heater pattern (141) among the first heater patterns (141) and the other end in contact with one surface of a corresponding second pattern (151) among the second heater patterns (151). The conductive member (170) has an upper surface (172) and a lower surface (173) located on the opposite side of the upper surface (172). A conductive adhesive sheet is formed by including conductive fillers in a resin, for example, an acrylic resin or a urethane resin. The conductive member (170) is cut from the conductive adhesive sheet to form, for example, a cylindrical shape or a square column shape. The bottom diameter of the conductive member (170) in contact with the corresponding first heater pattern (141) and the corresponding second heater pattern (151) is, for example, about 0.1 mm to 3 mm. In addition, the height of the conductive member (170) is equal to the distance between the opposing surfaces of the corresponding first heater pattern (141) and the corresponding second heater pattern (151). The height of the conductive member (170) is, for example, about 60 μm to 70 μm.

[0026] The conductive member (170) can be adhesively bonded to the corresponding first heater pattern (141) in a semi-cured state and is formed of a material having a hardness in the semi-cured state higher than that of the insulating resin forming the second insulating resin layer (150). Accordingly, when the second insulating resin layer (150) is formed on the first insulating resin layer (140) and the second insulating resin layer (150) is pressed against the insulating resin layer (140) while one end of the conductive member (170) is adhesively bonded to the corresponding first heater pattern (141), the other end of the conductive member (170) penetrates the second insulating resin layer (150). As a result, the other end of the conductive member (170) reaches the surface of the corresponding second heater pattern (151), so that the upper surface (172) of the conductive member (170) contacts the surface of the corresponding first heater pattern (141) and the lower surface (173) of the conductive member (170) contacts the surface of the corresponding second heater pattern (151). Additionally, the upper surface (172) of the conductive member (170) is coplanar with the surface of the corresponding first heater pattern (141), and the lower surface (173) of the conductive member (170) is coplanar with the surface of the corresponding second heater pattern (151).

[0027] When power is supplied from the base plate (110) to the second heater pattern (151) through the power supply unit (161) in the substrate fixing device (100) having such a configuration, power is also supplied to the first heater pattern (141) through the conductive member (170). When voltage is applied to the first heater patterns (141) and the second heater patterns (151), the first heater patterns (141) and the second heater patterns (151) generate heat to heat the ceramic layer (130) and heat the object adsorbed on the ceramic layer (130).

[0028] In the substrate fixing device (100), the temperature of the ceramic layer (130) is controlled by heating by the first heater pattern (141) and the second heater pattern (151) and cooling by the base plate (110), so that the temperature of the object adsorbed to the ceramic layer (130) can be controlled to a desired temperature. Additionally, the second heater patterns (151) can function as bypass electrodes that electrically connect the electrodes of the first heater patterns (141) to each other or electrically connect the first heater patterns (141) to the power supply units (161), instead of functioning as heating heater electrodes.

[0029] Meanwhile, when the second heater patterns (151) function as bypass electrodes, the second heater patterns (151) may be formed using a low-resistance conductor such as copper or a copper alloy. Additionally, in the substrate fixing device (100) described above, the thermal conductivity of the insulating resin layers may be improved by including fillers such as alumina or aluminum nitride in the first insulating resin layer (140), the second insulating resin layer (150), and the third insulating resin layer (160).

[0030] Next, a method for manufacturing a substrate fixing device (100) having the above-described configuration is explained with reference to the flowchart shown in FIG. 3.

[0031] First, a ceramic layer (130) for adsorbing an object is formed (step S101). Specifically, for example, a plurality of green sheets containing aluminum oxide as a main material are produced, and electrodes (131) are appropriately formed on one surface of the green sheets. The electrodes (131) can be formed, for example, by screen printing a metal paste onto the surface of the green sheets. Then, a plurality of green sheets are stacked and fired. As a result, a ceramic layer (130) is formed. The ceramic layer (130) has a layer of electrodes (131) inside, for example, as shown in FIG. 4.

[0032] When the ceramic layer (130) is formed, a first insulating resin layer (140) is provided on the surface of the ceramic layer (130) (step S102). A metal foil layer is formed on the side of the first insulating resin layer (140) opposite to the ceramic layer (130). That is, for example, as shown in FIG. 5, a first insulating resin layer (140) with a thickness of about 40 μm to 100 μm is formed on the surface of the ceramic layer (130), including a metal foil layer (141a) formed with a thickness of about 25 μm to 50 μm on one side of the first insulating resin layer (140). The first insulating resin layer (140) and the metal foil layer (141a) are bonded to the ceramic layer (130) by vacuum hot press bonding based on vacuum lamination and pressing.

[0033] The first insulating resin layer (140) is formed using an insulating resin with high heat resistance and thermal conductivity, such as epoxy resin or bismaleimide-triazine resin. Additionally, for example, to improve the thermal conductivity of the first insulating resin layer (140), fillers such as alumina or aluminum nitride may be included in the first insulating resin layer (140). Meanwhile, any rolled alloy exemplified as the material for the first heater patterns (141) and the second heater patterns (151) may be used as the material for the metal foil layer (141a). That is, the metal foil layer (141a) is made of an alloy such as CN49 (constantan) (Cu-Ni-Mn-Fe alloy), geranine (Cu-Mn-Sn alloy), or manganin (Cu-Mn-Ni alloy).

[0034] When the first insulating resin layer (140) is provided, the metal foil layer (141a) is etched, for example, using photolithography, to form first heater patterns (141) having desired patterns (step S103). That is, a resist is formed on the upper surface of the metal foil layer (141a), and the resist is exposed and developed to form resist patterns to cover the portions to be left as the first heater patterns (141). The exposed metal foil layer (141a) that is not covered by the resist patterns is removed by etching. As a result, first heater patterns (141) having desired shapes are formed, for example, as shown in FIG. 6. FIG. 6 is illustrated in a cross-sectional view of, for example, two concentric first heater patterns (141).

[0035] Once the first heater patterns (141) are formed, conductive members (170) are placed on the surfaces of the first heater patterns (141) (step S104). Specifically, the conductive adhesive sheet comprises conductive fillers in a resin such as acrylic resin or urethane resin. The thickness of the conductive adhesive sheet is, for example, 40 μm to 100 μm. The conductive members (170) are each cut from the conductive adhesive sheet to have a cylindrical shape with a bottom diameter of about 0.1 mm to 3 mm. The conductive members (170) thus formed are adhesively bonded to the upper surfaces of the first heater patterns (141). Additionally, the conductive members (170) may be formed into a cylindrical or rectangular column shape cut from an assembly that bonds a plurality of conductive adhesive sheets onto each other.

[0036] Conductive members (170) are positioned at locations where they can be electrically connected to the first heater patterns (141) and the second heater patterns (151), for example, as shown in FIG. 7. Since the conductive members (170) are formed by cutting from a conductive adhesive sheet, the positions of the conductive members (170) can be easily fixed when the conductive members (170) are adhesively bonded to the upper surface of the first heater patterns (141). Additionally, at the time the conductive members (170) are adhesively bonded to the first heater patterns (141), the resin forming the conductive members (170) is in a semi-cured state, and the semi-cured conductive members (170) have a higher hardness than the semi-cured insulating resin formed as the second insulating resin layer (150). Additionally, to increase the hardness of the semi-cured conductive members (170), the conductive members (170) can be heated and cured within a predetermined range after the conductive members (170) are adhesively bonded to the first heater patterns (141).

[0037] If conductive members (170) are disposed on the first heater patterns (141), a second insulating resin layer (150) is formed to cover the first heater patterns (141) (step S105). A metal foil layer is formed on the side of the second insulating resin layer (150) opposite to the first heater patterns (141). That is, for example, as shown in FIG. 8, a second insulating resin layer (150) having a thickness of for example about 40 μm to 100 μm, comprising a metal foil layer (151a) formed on one side of the second insulating resin layer (150) with a thickness of for example 25 μm to 50 μm, is formed on the upper surfaces of the first insulating resin layer (140) and the first heater patterns (141). The second insulating resin layer (150) and the metal foil layer (151a) are bonded to the first insulating resin layer (140) by vacuum hot press bonding based on vacuum lamination and pressing.

[0038] The second insulating resin layer (150) is formed using an insulating resin with high heat resistance and thermal conductivity, such as epoxy resin or bismaleimide-triazine resin. Additionally, to improve the thermal conductivity of the second insulating resin layer (150), fillers such as alumina or aluminum nitride may be included in the second insulating resin layer (150). Meanwhile, as the material for the metal foil layer (151a), any rolled alloy exemplified as the material for the first heater patterns (141) and the second heater patterns (151) may be used. That is, the metal foil layer (151a) is made of an alloy such as CN49 (constantan) (Cu-Ni-Mn-Fe alloy), geranine (Cu-Mn-Sn alloy), or manganin (Cu-Mn-Ni alloy).

[0039] Additionally, the second heater patterns (151) may function as bypass electrodes that electrically connect the electrodes of the first heater patterns (141) or electrically connect the first heater patterns (141) and the power supply units (161), instead of functioning as heating heater electrodes. When the second heater patterns (151) function as bypass electrodes, a metal with low electrical resistance, such as copper or a copper alloy, may be used as the material for the metal foil layer (151a).

[0040] When the second insulating resin layer (150) is provided, the insulating resin forming the second insulating resin layer (150) is in a semi-cured state and has a lower hardness than the conductive members (170). Therefore, the insulating resin forming the second insulating resin layer (150) is pushed out by the conductive members (170). As a result, the conductive members (170) penetrate the second insulating resin layer (150), and the upper ends of the conductive members (170) come into contact with the lower surface of the metal foil layer (151a) formed on the surface of the second insulating resin layer (150). Thus, one end of the conductive members (170) comes into contact with the upper surface of the first heater patterns (141), and the other end of the conductive members (170) comes into contact with the lower surface of the metal foil layer (151a). Additionally, during vacuum hot press bonding applied to the second insulating resin layer (150), the second insulating resin layer (150) is cured and the conductive members (170) are also cured by heating and pressurizing. During deposition, the second insulating resin layer (150) is pressed and the conductive members (170) are cured. Thus, the conductive members (170) can be firmly in contact with the lower surface of the metal foil layer (151a), and the connection reliability between the two layers of heater patterns can be improved.

[0041] Once the second insulating resin layer (150) is provided, the metal foil layer (151a) is etched, for example, using photolithography, to form second heater patterns (151) having desired patterns (step S106). That is, a resist is formed on the upper surface of the metal foil layer (151a), and the resist is exposed and developed to form resist patterns that cover the portion to be left as the second heater patterns (151). Subsequently, the exposed metal foil layer (151a) not covered by the resist patterns is removed by etching to form second heater patterns (151) having desired shapes, for example, as shown in FIG. 9. As shown in FIG. 9, the second heater patterns (151) are located at positions where at least a portion of the second heater patterns (151) does not overlap with the first heater patterns (141). That is, at least some portions of the second heater patterns (151) are formed in locations that overlap with areas where the first heater patterns (141) are not formed when viewed in a plane. Additionally, other portions of the second heater patterns (151) are formed in locations that overlap with the first heater patterns (141) in areas including the locations of the conductive members (170) when viewed in a plane.

[0042] FIG. 10 is a drawing showing a specific example of the first heater patterns (141). FIG. 11 is a drawing showing a specific example of the second heater patterns (151). As shown in FIG. 10, when the first heater patterns (141) are formed in the shape of two concentric circles, conductive members (170) are formed at positions that contact the electrodes forming the concentric circles, respectively. As shown in FIG. 11, when the second heater patterns (151) are formed at positions where, when viewed in a plane, a part of the second heater patterns (151) overlaps with the first heater patterns (141) and another part of the second heater patterns (151) does not overlap, conductive members (170) are formed in the parts of the areas where the second heater patterns (151) overlap with the first heater patterns (141) when viewed in a plane.

[0043] In this way, in regions including the locations of the conductive members (170), the first heater patterns (141) and the second heater patterns (151) overlap when viewed in a plane, and one end of the conductive members (170) contacts the upper surface of the first heater patterns (141), while the other end of the conductive members (170) contacts the lower surface of the second heater patterns (151). Accordingly, the first heater patterns (141) and the second heater patterns (151) are electrically connected to each other through the conductive members (170) without undergoing a via formation step. That is, the connection between the two layers of heater patterns can be achieved in simple steps, thereby improving the manufacturing efficiency of the electrostatic chuck (120) and the substrate fixing device (10).

[0044] If second heater patterns (151) connected to first heater patterns (141) through conductive members (170) are formed, a third insulating resin layer (160) is formed to cover the second heater patterns (151) (step S107). Specifically, the third insulating resin layer (160) in a semi-cured state is formed to cover the second insulating resin layer (150) and the second heater patterns (151). Subsequently, the third insulating resin layer (160) is heated and pressurized to cure the third insulating resin layer (160). As a result, two layers of heaters are formed in which the first heater patterns (141) and the second heater patterns (151) are connected to each other through conductive members (170), for example, as shown in FIG. 12.

[0045] Next, openings are formed in the third insulating resin layer (160) at positions corresponding to the electrode pads of the second heater patterns (151) (step S108). That is, openings (161a) are formed in the third insulating resin layer (160) so as to expose the second heater patterns (151) at positions that function as electrode pads in contact with the power supply portions (161), for example, as shown in FIG. 13. In this way, an electrostatic chuck (120) can be obtained in which the two layers of heater electrodes are connected to each other through a conductive member (170).

[0046] The electrostatic chuck (120) is bonded to the base plate (110) using an adhesive (step S109). Specifically, the surface of the third insulating resin layer (160) in which the openings (161a) are formed is bonded to the base plate (110) using, for example, a silane coupling agent and an adhesive. In this case, the position of the openings (161a) is bonded so that it is aligned with the position of the power supply portions (161). Thus, the power supply portions (161) and the second heater patterns (151) come into contact with each other, so that power can be supplied to the second heater patterns (151). Additionally, the second heater patterns (151) are connected to the first heater patterns (141) through conductive members (170). Thus, power can also be supplied to the first heater pattern (141). When the electrostatic chuck (120) is bonded to the base plate (110), the substrate fixing device (100) is completed.

[0047] According to the present embodiment, as described above, with conductive members disposed on the surface of the first heater patterns, an insulating resin layer is formed to cover the first heater patterns, and the conductive members penetrate the insulating resin layer. Then, the leading ends of the conductive members that have penetrated the insulating resin layer come into contact with the second heater patterns. Accordingly, the first heater patterns and the second heater patterns can be electrically connected to each other through the conductive members without forming any vias connecting the first heater patterns and the second heater patterns. As a result, the step of forming via holes in the insulating resin layer and filling the via holes with metal paste can be omitted, thereby improving manufacturing efficiency.

[0048] In addition, in the manufacturing method of the background technology, in which a via hole is first formed in an insulating resin layer and then a metal paste is filled into the via hole to form a via that electrically connects a first heater pattern to a second heater pattern, it is determined that the metal paste cannot be completely filled into the via hole. In this case, the reliability of the electrical connection between the via and the heater patterns cannot be sufficiently ensured. Meanwhile, according to the present embodiment, the lower and upper surfaces of the conductive members (170) firmly contact the first heater patterns (141) and the second heater patterns (151). Therefore, the reliability of the electrical connection between the first heater patterns (141) and the second heater patterns (151) can be further improved by the conductive members (170).

[0049] In addition, in the above-described embodiment, two layers of heater electrodes, namely first heater patterns (141) and second heater patterns (151), are provided in the electrostatic chuck (120). However, instead, three or more layers of heater patterns may be provided in the electrostatic chuck (120). Even when three or more layers of heater patterns are provided, conductive members are placed on the surface of each layer of the heater patterns, and an insulating resin layer is deposited thereon so that the conductive members penetrate the insulating resin layer and come into contact with the upper layer of the heater patterns. Accordingly, the upper and lower layers of the heater patterns can be easily electrically connected, thereby increasing manufacturing efficiency.

[0050] Additionally, in the above-described embodiment, electrode pads are formed in portions of the first heater patterns (141) that contact the conductive members (170), or in portions of the second heater patterns (151) that contact the power supply portions (161). The electrode pads are regions having a diameter greater than a certain size so as to be firmly connected to the conductive members (170) or the power supply portions (161). The periphery of the electrode pads tends to be blank regions of the heater patterns. Therefore, the temperature around the periphery of the electrode pads tends to decrease, which may lead to a decrease in thermal uniformity.

[0051] Accordingly, in the above-described embodiment, the electrode pads of the heater patterns on one layer side can overlap with the heater patterns on the other layer side, thereby preventing a temperature drop around the electrode pads and improving thermal uniformity.

[0052] Additionally, in the above-described embodiment, the conductive members (170) are formed from a material comprising a resin and conductive fillers in the resin, but the conductive members (170) may instead be formed from another conductor. However, the conductive members (170) are formed from a material having a higher hardness than the insulating resin forming the second insulating resin layer (150). Accordingly, when the second insulating resin layer (150) is formed to cover the first heater patterns (141) on which the conductive members (170) are arranged, the ends of the conductive members (170) penetrate the second insulating resin layer (150) and come into contact with the metal foil layer (151a).

[0053] Although preferred embodiments and the like have been described in detail above, the present disclosure is not limited to the embodiments and the like, and various modifications and substitutions can be made to the embodiments and the like without departing from the scope described in the claims.

Claims

Claim 1 A substrate fixing device comprising: a base plate; and an electrostatic chuck fixed to the base plate and configured to adsorb a substrate by electrostatic force, wherein the electrostatic chuck comprises: a ceramic layer formed of ceramic, wherein the ceramic layer is configured to adsorb the substrate while in contact with the substrate; a first heater pattern disposed on the ceramic layer and configured to generate heat; an insulating resin layer disposed on the first heater pattern to cover the first heater pattern; a second heater pattern disposed on the insulating resin layer and configured to generate heat; and a conductive member penetrating the insulating resin layer such that one end of the conductive member contacts the surface of the first heater pattern and the other end of the conductive member contacts the surface of the second heater pattern, wherein the conductive member is formed of a material having a higher hardness than the insulating resin forming the insulating resin layer, and the conductive member is formed of a material comprising a resin and a conductive filler contained in the resin. Claim 2 A substrate fixing device according to claim 1, wherein the conductive member comprises an upper surface and a lower surface opposite to the upper surface, the upper surface of the conductive member is coplanar with the surface of the first heater pattern, and the lower surface of the conductive member is coplanar with the surface of the second heater pattern. Claim 3 delete Claim 4 A substrate fixing device according to claim 1 or 2, wherein the conductive member comprises an upper surface and a lower surface opposite to the upper surface, the upper surface contacts the first heater pattern and the lower surface contacts the second heater pattern, and the diameter of each of the upper surface and the lower surface is within the range of 0.1 mm to 3 mm. Claim 5 In claim 1 or 2, the conductive member is a substrate fixing device that overlaps with the first heater pattern and the second heater pattern when viewed in a planar view. Claim 6 A substrate fixing device according to claim 1 or 2, wherein the ceramic layer comprises: the electrode configured to generate an electrostatic force according to a voltage applied to the electrode; and the ceramic surrounding the electrode. Claim 7 An electrostatic chuck comprising: a ceramic layer formed of ceramic and configured to adsorb an object; a first heater pattern disposed on the ceramic layer and configured to generate heat; an insulating resin layer disposed on the first heater pattern to cover the first heater pattern; a second heater pattern disposed on the insulating resin layer and configured to generate heat; and a conductive member penetrating the insulating resin layer such that one end of the conductive member contacts the surface of the first heater pattern and the other end of the conductive member contacts the surface of the second heater pattern, wherein the conductive member is formed of a material having a higher hardness than the insulating resin forming the insulating resin layer, and the conductive member is formed of a material comprising a resin and a conductive filler contained in the resin. Claim 8 An electrostatic chuck according to claim 7, wherein the conductive member comprises an upper surface and a lower surface opposite to the upper surface, the upper surface of the conductive member is coplanar with the surface of the first heater pattern, and the lower surface of the conductive member is coplanar with the surface of the second heater pattern. Claim 9 A method for manufacturing an electrostatic chuck, comprising: forming a ceramic layer including an electrode and a ceramic surrounding the electrode; forming a first heater pattern on the ceramic layer ― the first heater pattern is configured to generate heat ―; placing a conductive member on the surface of the first heater pattern; providing an insulating resin layer on the ceramic layer to cover the conductive member and the first heater pattern ― a metal layer is formed on one surface of the insulating resin layer ―; and patterning the metal layer to form a second heater pattern, wherein the conductive member penetrates the insulating resin layer to contact the metal layer in the step of providing the insulating resin layer, and the conductive member is formed of a resin including a conductive filler. Claim 10 In claim 9, a method of penetrating the insulating resin layer by applying pressure and heating to the insulating resin layer in the step of providing the insulating resin layer, so that the conductive member contacts the metal layer. Claim 11 A method according to claim 9 or 10, wherein the conductive member is formed of a material having a higher hardness than the insulating resin forming the insulating resin layer. Claim 12 A method according to claim 9 or 10 in which the conductive member is disposed on the surface of the first heater pattern in a semi-cured state. Claim 13 A method according to claim 9 or 10, wherein the step of placing the conductive member comprises the step of heating the conductive member placed on the first heater pattern to cure the conductive member to a predetermined range.

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