Electrostatic chuck member, electrostatic chuck device, and method for manufacturing electrostatic chuck member

Abstract

Provided is an electrostatic chuck member on which a plate-shaped sample is placed, and that comprises: a first substrate and a second substrate laminated in a thickness direction; and a layered heater electrode provided between the first substrate and the second substrate. The heater electrode has a belt shape forming a predetermined pattern when viewed from the thickness direction. In the thickness direction, the first substrate side is defined as a first side, the second substrate side is defined as a second side, the plate-shaped sample is placed on the first side with respect to the heater electrode, and a first width of an end portion of the first side of the heater electrode is larger than a second width of an end portion of the second side of the heater electrode.

Description

Electrostatic chuck member, electrostatic chuck device, and method for manufacturing an electrostatic chuck member

[0001] The present invention relates to an electrostatic chuck member, an electrostatic chuck device, and a method for manufacturing an electrostatic chuck member. This application claims priority under Japanese Patent Application No. 2024-196274, filed on November 8, 2024, the contents of which are incorporated herein by reference.

[0002] In the semiconductor manufacturing process, plate-shaped samples such as silicon wafers are fixed to an electrostatic chuck member by electrostatic adsorption and subjected to predetermined processing. The electrostatic chuck member has a substrate which is a ceramic molded body, electrostatic adsorption electrodes provided inside the substrate for electrostatically adsorbing the plate-shaped sample, and heater electrodes for suppressing temperature unevenness of the plate-shaped sample (see, for example, Patent Document 1). The heater electrodes are continuous linear (or strip-shaped) members. The surface of the substrate is the surface on which the plate-shaped sample is adsorbed and fixed by the electrostatic chuck member (the mounting surface of the plate-shaped sample).

[0003] Japanese Patent Publication No. 2012-209499

[0004] A heater electrode generates resistive heat when current is passed from one end to the other. Such a heater electrode can increase its resistance and thus its heat output by reducing its cross-sectional area (conductor cross-sectional area) perpendicular to its length. On the other hand, reducing the cross-sectional area of ​​the heater electrode, i.e., making it thin, makes it difficult to secure sufficient contact area between the heater electrode and the substrate, thus hindering the efficient transfer of heat from the heater electrode to the substrate's mounting surface.

[0005] The present invention has been made in view of these circumstances, and one of its objectives is to provide an electrostatic chuck member, an electrostatic chuck device, and a method for manufacturing an electrostatic chuck member that can suppress temperature unevenness of a plate-shaped sample held on a mounting surface by efficiently transferring heat from a heater electrode to a plate-shaped sample.

[0006] To solve the above problems, one aspect of the present invention includes the following aspects.

[0007] [1] An electrostatic chuck member for mounting a plate-shaped sample, comprising: a first substrate and a second substrate stacked in the thickness direction; and a layered heater electrode provided between the first substrate and the second substrate, wherein the heater electrode is strip-shaped and forms a predetermined pattern when viewed from the thickness direction, the first substrate side is designated as the first side and the second substrate side as the second side in the thickness direction, the plate-shaped sample is mounted on the first side with respect to the heater electrode, and the first width dimension of the first side end of the heater electrode is greater than the second width dimension of the second side end of the heater electrode.

[0008] [2] The electrostatic chuck member according to [1], wherein the difference between the first width dimension and the second width dimension is greater than or equal to the thickness dimension of the heater electrode disposed between the first substrate and the second substrate.

[0009] [3] An electrostatic chuck member according to [1] or [2], wherein an insulating portion is provided between adjacent heater electrodes between the first substrate and the second substrate, and the third width dimension of the first end of the insulating portion is smaller than the fourth width dimension of the second end of the insulating portion.

[0010] [4] The electrostatic chuck member according to [3], wherein the ratio of the difference between the first width dimension and the second width dimension to the difference between the third width dimension and the fourth width dimension is 0.7 or more and 1.3 or less.

[0011] [5] The electrostatic chuck member according to [3] or [4], wherein the side surface of the heater electrode and the side surface of the insulating part face each other with a gap in between.

[0012] [6] The electrostatic chuck member according to [5], wherein the width dimension of the gap is greater than or equal to the thickness dimension of the heater electrode disposed between the first substrate and the second substrate, and less than or equal to the fourth width dimension.

[0013] [7] The electrostatic chuck member according to any one of [3] to [6], wherein the resistivity of the material constituting the insulating portion is greater than the resistivity of the materials constituting the first substrate and the second substrate.

[0014] [8] The electrostatic chuck member according to any one of [1] to [7], comprising a power supply terminal for supplying power to the heater electrode, wherein the second substrate is provided with a through hole that penetrates in the thickness direction and into which the power supply terminal is inserted, and the heater electrode has an intrusion portion located between the inner circumferential surface of the through hole and the outer circumferential surface of the power supply terminal.

[0015] [9] The electrostatic chuck member according to [8], wherein the dimension of the penetration portion in the thickness direction is greater than the thickness dimension of the heater electrode disposed between the first substrate and the second substrate.

[0016]

[10] The electrostatic chuck member according to any one of [1] to [9], wherein the side surface of the heater electrode has a first region located at the end on the first side and a second region located to the second side of the first region, the first region is inclined at an angle of 0° or more in the direction toward the inside in the width direction of the heater electrode as it approaches the first side, and the second region is inclined at an angle greater than 0° in the direction toward the outside in the width direction of the heater electrode as it approaches the first side.

[0017]

[11] The electrostatic chuck member according to any one of [1] to [8], wherein the heater electrode is made of a thin metal plate.

[0018]

[12] An electrostatic chuck device comprising an electrostatic chuck member described in any one of [1] to

[11] , and a base for cooling the electrostatic chuck member and adjusting the temperature of the electrostatic chuck member.

[0019]

[13] A method for manufacturing an electrostatic chuck member for mounting a plate-shaped sample on a first side in the thickness direction, comprising: a first coating step of applying an electrode paste in a strip shape to a first coated surface of a first substrate; a drying step of drying the electrode paste and shrinking the electrode paste so that its width dimension decreases as it moves away from the first coated surface; a lamination step of placing the first substrate on top of the second substrate from the first side with the first coated surface facing the second substrate; and a sintering step of sintering the electrode paste.

[0020]

[14] A method for manufacturing an electrostatic chuck member according to

[13] , comprising a second coating step performed before the drying step, wherein an insulating paste is applied to the second coated surface of the second substrate, the drying step dries the insulating paste together with the electrode paste and shrinks the insulating paste so that its width decreases as it moves away from the second coated surface, and the sintering step sinters the insulating paste together with the electrode paste.

[0021]

[15] A method for manufacturing an electrostatic chuck member according to

[13] or

[14] , comprising: a through-hole forming step performed before the lamination step to form through holes in the second substrate; and an insertion step performed after the lamination step and before the sintering step to insert electrode terminals into the through-holes and bring them into contact with the electrode paste.

[0022]

[16] A method for manufacturing an electrostatic chuck member on which a plate-shaped sample is mounted on a first side in the thickness direction, comprising: an electrode forming step of cutting a plate-shaped metal material from the first surface side by etching or laser processing to form a strip-shaped heater electrode; and a lamination step of laminating a first substrate and a second substrate with the heater electrode sandwiched between them, wherein in the lamination step, the first surface is positioned facing the second side opposite to the first side in the thickness direction.

[0023]

[17] A method for manufacturing an electrostatic chuck member according to

[16] , comprising a groove formation step performed before the lamination step to form a groove in the second substrate, wherein in the lamination step, the heater electrode is arranged inside the groove, and the width dimension of the groove increases toward the first side.

[0024] According to the present invention, it is possible to provide an electrostatic chuck member, an electrostatic chuck device, and a method for manufacturing an electrostatic chuck member that can suppress temperature unevenness in a plate-shaped sample by efficiently transferring heat from a heater electrode to the plate-shaped sample.

[0025] Figure 1 is a schematic cross-sectional view showing an electrostatic chuck device and electrostatic chuck member of the first embodiment. Figure 2 is an enlarged cross-sectional view of the electrostatic chuck member of the first embodiment. Figure 3 is a flowchart showing the manufacturing method of the electrostatic chuck member of the first embodiment. Figure 4 is a schematic diagram showing the manufacturing process of the electrostatic chuck member of the first embodiment. Figure 5 is a schematic diagram showing the manufacturing process of the electrostatic chuck member of the first embodiment. Figure 6 is an image of a cross-section of the heater electrode and insulating part of the first embodiment. Figure 7 is an image of a cross-section of the heater electrode and second power supply terminal of the first embodiment. Figure 8 is an enlarged cross-sectional view of the electrostatic chuck member of the second embodiment. Figure 9 is a flowchart showing the manufacturing method of the electrostatic chuck member of the second embodiment. Figure 10 is a schematic diagram showing the electrode formation process by etching of the second embodiment. Figure 11 is a schematic diagram showing the electrode formation process by laser processing of the second embodiment. Figure 12 is a schematic diagram showing the lamination process of the second embodiment.

[0026] The electrostatic chuck member and electrostatic chuck device according to this embodiment will be described below with reference to the drawings. Note that in all the following drawings, the dimensions and proportions of each component have been appropriately altered for clarity.

[0027] <First Embodiment> (Electrostatic Chuck Device) Figure 1 is a schematic cross-sectional view showing an electrostatic chuck device 1 and an electrostatic chuck member 2 of the first embodiment. The electrostatic chuck device 1 includes an electrostatic chuck member 2 on which a mounting surface 2s for mounting a wafer (plate-shaped sample) W is provided, a base 3 that supports the electrostatic chuck member 2 from the opposite side of the mounting surface 2s, a plurality of first power supply terminals 16A, and a plurality of second power supply terminals 16B. A focus ring (not shown) surrounding the wafer W may be arranged on the outer periphery of the upper surface of the electrostatic chuck member 2.

[0028] Furthermore, the Z-axis is shown in each figure. In this specification, the Z-axis indicates the thickness direction of the first ceramic plate (first substrate) 11 and the second ceramic plate (second substrate) 12 (the thickness direction of the electrostatic chuck member 2), which will be described later. The Z-axis is assumed to extend in the vertical direction, and the direction in which the arrow of the Z-axis points is considered the upper side (first side), and the opposite side is considered the lower side (second side), as each part of the electrostatic chuck device 1 is described. Also, in this specification, "plan view" means viewing the object from above in the Z-axis direction.

[0029] (Electrostatic Chuck Member) The electrostatic chuck member 2 is disc-shaped. The electrostatic chuck member 2 includes a first ceramic plate 11, a second ceramic plate 12, a heater electrode 21, and an insulating portion 22. The first ceramic plate 11 corresponds to the "first substrate" in the present invention, and the second ceramic plate 12 corresponds to the "second substrate" in the present invention. The first ceramic plate 11 and the second ceramic plate 12 are stacked in the thickness direction. The heater electrode 21 and the insulating portion 22 are provided between the first ceramic plate 11 and the second ceramic plate 12.

[0030] (First ceramic plate) The first ceramic plate 11 is a circular plate in plan view. The upper surface of the first ceramic plate 11 is the mounting surface 2s of the electrostatic chuck member 2.

[0031] An electrostatic adsorption electrode 13 is provided inside the first ceramic plate 11. The first ceramic plate 11 has a mounting surface 2s facing upward and a first opposing surface 11f facing downward. The mounting surface 2s may have, for example, a plurality of protrusions (not shown) formed at predetermined intervals. The mounting surface 2s supports the wafer W with the tips of the plurality of protrusions. The first opposing surface 11f faces the second ceramic plate 12.

[0032] The first ceramic plate 11 has a first plate portion 11a, a second plate portion 11b, a third plate portion 11c, a first bonding layer 11d, and a second bonding layer 11e. The first plate portion 11a, the second plate portion 11b, and the third plate portion 11c are plate-shaped with the Z-axis direction as the thickness direction. The first plate portion 11a, the second plate portion 11b, and the third plate portion 11c are stacked in this order from top to bottom in the thickness direction.

[0033] Between the first plate portion 11a and the second plate portion 11b, a first bonding layer 11d and an electrostatic adsorption electrode 13 are arranged. The first bonding layer 11d is provided so as to surround the electrostatic adsorption electrode 13. The first bonding layer 11d joins the first plate portion 11a and the second plate portion 11b. The electrostatic adsorption electrode 13 extends in a layered manner along a plane orthogonal to the thickness direction (Z-axis direction) of the first ceramic plate 11. Thereby, the electrostatic adsorption electrode 13 is embedded inside the first ceramic plate 11.

[0034] In this specification, "layered" means a state having a portion forming a layer or recognized as a layer between the first ceramic plate 11 and the second ceramic plate 12. In this sense, the "layer" may be a single layer or a plurality of layers.

[0035] Between the second plate portion 11b and the third plate portion 11c, a second bonding layer 11e is arranged. The second bonding layer 11e joins the second plate portion 11b and the third plate portion 11c. Note that a bias electrode surrounded by the second bonding layer 11e may be arranged between the second plate portion 11b and the third plate portion 11c.

[0036] The second plate portion 11b and the third plate portion 11c may be provided with through holes 11k penetrating in the thickness direction. The through holes 11k may be circular in plan view. A first power supply terminal 16A is inserted into the through holes 11k.

[0037] The first ceramic plate 11 is formed by applying, between a first plate portion 11a, a second plate portion 11b, and a third plate portion 11c which are a sintered body formed by sintering in advance, unsintered pastes constituting the electrostatic adsorption electrode 13, the first bonding layer 11d, and the second bonding layer 11e, laminating them in the thickness direction, and integrally hot pressing them under high temperature and high pressure.

[0038] The first plate portion 11a, the second plate portion 11b, the third plate portion 11c, the first bonding layer 11d, and the second bonding layer 11e constituting the first ceramic plate 11 are made of a ceramic material. Examples of the ceramic material constituting the first ceramic plate 11 include aluminum oxide (Al ２ O ３), sintered bodies, aluminum nitride (AlN) sintered bodies, aluminum oxide (Al ２ O ３ ) - silicon carbide (SiC) composite sintered bodies and the like are preferably used. The first plate portion 11a, the second plate portion 11b, the third plate portion 11c, the first bonding layer 11d, and the second bonding layer 11e may be composed of materials having the same composition. The first plate portion 11a, the second plate portion 11b, the third plate portion 11c, the first bonding layer 11d, and the second bonding layer 11e may be composed of mutually different materials.

[0039] The electrostatic adsorption electrode 13 is a composite of an insulating substance and a conductive substance. The insulating substance contained in the electrostatic adsorption electrode 13 is not particularly limited. For example, Al ２ O ３ , AlN, silicon nitride (Si ３ N ４ ), yttrium (III) oxide (Y ２ O ３ ), yttrium aluminum garnet (YAG), and SmAlO ３ It is preferably at least one selected from the group consisting of.

[0040] A columnar first power supply terminal 16A may be connected to the electrostatic adsorption electrode 13. The first power supply terminal 16A applies a voltage to the electrostatic adsorption electrode 13. When a voltage is applied to the electrostatic adsorption electrode 13, an electrostatic adsorption force for holding the wafer W on the mounting surface 2s is generated. The first power supply terminal 16A penetrates the second plate portion 11b, the third plate portion 11c, the second ceramic plate 12, and the base 3. A cylindrical insulator 18 for insulation may be attached to a part of the outer peripheral surface of the first power supply terminal 16A. The insulator 18 insulates the first power supply terminal 16A and the base 3 from each other.

[0041] (Second ceramic plate) The second ceramic plate 12 is circular plate-shaped in plan view. The second ceramic plate 12 has a second opposing surface 12f facing upward. The second opposing surface 12f faces the first opposing surface 11f of the first ceramic plate 11 in the vertical direction.

[0042] The second ceramic plate 12 may be provided with through holes 12d and 12h that penetrate in the thickness direction. The through holes 12d and 12h may be circular in plan view. The first power supply terminal 16A may be inserted into the through hole 12d. The second power supply terminal 16B may be inserted into the through hole 12h.

[0043] The second ceramic plate 12 is made of a ceramic material. Examples of ceramic materials that make up the second ceramic plate 12 include Al ２ O ３ Sintered body, AlN sintered body, Al ２ O ３ - SiC composite sintered bodies are preferably used. The second ceramic plate 12 may be made of the same material as the first ceramic plate 11. However, the second ceramic plate 12 may be made of a different material than the first ceramic plate 11. Also, the second ceramic plate 12 is made from a single sintered body. However, the second ceramic plate 12 may be made by stacking and joining multiple sintered bodies in the thickness direction. In this case, the multiple sintered bodies may be made of different ceramic materials.

[0044] (Heater electrode, insulating part) The heater electrode 21 and the insulating part 22 are located between the first ceramic plate 11 and the second ceramic plate 12. Both the heater electrode 21 and the insulating part 22 are layered. The thickness direction of the heater electrode 21 coincides with the thickness direction of the first ceramic plate 11 and the second ceramic plate 12.

[0045] The heater electrode 21 is strip-shaped and forms a predetermined pattern. Cylindrical second power supply terminals 16B are connected to both ends of the heater electrode 21 in the longitudinal direction. The second power supply terminals 16B supply current to the heater electrode 21. That is, the second power supply terminals 16B supply power to the heater electrode 21. The second power supply terminals 16B are connected to the surface facing downwards of the heater electrode 21 and extend downwards from the heater electrode 21. The second power supply terminals 16B penetrate the second ceramic plate 12 and the base 3. A cylindrical insulator 18 for insulation may be attached to a part of the outer circumferential surface of the second power supply terminals 16B. The insulator 18 insulates the second power supply terminals 16B from the base 3.

[0046] The insulating portion 22 is provided in a shape complementary to the heater electrode 21. The insulating portion 22 is located between a part of the strip-shaped heater electrode 21 and another part adjacent to that part, and insulates them from each other. Furthermore, the insulating portion 22 joins and integrates the first ceramic plate 11 and the second ceramic plate 12 around the heater electrode 21.

[0047] Preferably, the volume resistivity of the material constituting the insulating portion 22 is greater than the volume resistivity of the materials constituting the first ceramic plate 11 and the second ceramic plate 12. By making the volume resistivity of the insulating portion 22 greater than the volume resistivity of the first ceramic plate 11 and the second ceramic plate 12, the insulation between the heater electrodes 21 can be sufficiently improved. For example, the insulating portion 22 is made of Al ２ O ３ It is composed of, and the first ceramic plate 11 and the second ceramic plate 12 are made of Al ２ O ３ - When composed of a SiC composite sintered body, the above-mentioned volume resistivity relationship can be satisfied. The insulating portion 22 may be made of the same insulating material as the material constituting the first ceramic plate 11 and the second ceramic plate 12, for example.

[0048] Furthermore, if the first ceramic plate 11 and the second ceramic plate 12 are each composed of multiple components, the volume resistivity of the insulating portion 22 should be greater than the volume resistivity of the components that make up the first opposing surface 11f and the second opposing surface 12f.

[0049] The heater electrode 21 and the insulating part 22 will be described in detail later.

[0050] (Base) The base 3 is a disc-shaped member in plan view and supports the electrostatic chuck member 2 from below. A flow path 31 for circulating refrigerant is provided inside the base 3. The refrigerant flowing through the flow path 31 is water, He gas, N ２ Gases and the like are used. The refrigerant in the flow path 31 cools the entire base 3 and, by cooling the base 3, indirectly cools the electrostatic chuck member 2 that is in contact with the upper surface of the base 3, thereby adjusting the temperature of the electrostatic chuck member 2.

[0051] The base 3 is connected to an external high-frequency power supply via a matching circuit (not shown) and may also serve as an internal electrode for plasma generation.

[0052] (Other configurations) The electrostatic chuck device 1 may be provided with a gas flow path 19. The gas flow path 19 has a first gas hole 19a, a second gas hole 19b, and a connecting passage 19c. The first gas hole 19a and the second gas hole 19b communicate with each other via the connecting passage 19c, and together they constitute the gas flow path 19.

[0053] The first gas hole 19a extends downward from the communication passage 19c and connects to the heat transfer gas introduction section (not shown) at the lower end of the base 3. An insulator 18 is provided around the portion of the first gas hole 19a that passes through the base 3.

[0054] The second gas hole 19b extends upward from the connecting passage 19c and opens onto the mounting surface 2s.

[0055] The connecting passage 19c is located inside the electrostatic chuck member 2 and extends along the planar direction of the mounting surface 2s. In Figure 1, the connecting passage 19c is provided in the second bonding layer 11e described above.

[0056] A heat transfer gas flows through the gas channel 19. The heat transfer gas is a cooling gas, such as He. The heat transfer gas is supplied to the mounting surface 2s via the gas channel 19 and cools the wafer W mounted on the mounting surface 2s.

[0057] (Connection structure between heater electrode and second power supply terminal) Figure 2 is an enlarged cross-sectional view of the electrostatic chuck member 2 of the first embodiment, and is a cross-sectional view perpendicular to the direction in which the heater electrode 21 extends.

[0058] As shown in Figure 2, a second power supply terminal 16B is inserted into a through hole 12h provided in the second ceramic plate 12. A first chamfered portion 16k may be formed on the upper end of the outer circumferential surface of the second power supply terminal 16B, continuously in the circumferential direction of the second power supply terminal 16B. A second chamfered portion 12k may also be formed on the upper end of the inner circumferential surface of the through hole 12h, continuously in the circumferential direction of the through hole 12h. The area of ​​the outer circumferential surface of the second power supply terminal 16B below the first chamfered portion 16k is in contact with the area of ​​the inner circumferential surface of the through hole 12h below the second chamfered portion 12k. Note that the first chamfered portion 16k and the second chamfered portion 12k may each have discontinuous portions in the circumferential direction.

[0059] The first chamfered portion 16k may be formed naturally during the molding of the second power supply terminal 16B. In that case, the dimensions of the first chamfered portion 16k are sufficiently small. However, the first chamfered portion 16k may also be formed by chamfering the corner portion of the second power supply terminal 16B. Similarly, the second chamfered portion 12k may be formed naturally during the processing of the through hole 12h. In that case, the dimensions of the second chamfered portion 12k are sufficiently small. However, the second chamfered portion 12k may also be formed by chamfering the opening of the through hole 12h.

[0060] The first chamfered portion 16k and the second chamfered portion 12k face each other in the radial direction with a gap in between. A portion of the heater electrode 21 enters the gap between the first chamfered portion 16k and the second chamfered portion 12k. In the following description, the portion of the heater electrode 21 that enters the gap between the first chamfered portion 16k and the second chamfered portion 12k will be referred to as the entry portion 21p. That is, the heater electrode 21 has an entry portion 21p located between the inner circumferential surface of the through hole 12h and the outer circumferential surface of the second power supply terminal 16B.

[0061] The penetration portion 21p penetrates the second opposing surface 12f of the second ceramic plate 12 to a depth of D. In this embodiment, the penetration portion 21p is a closed annular ring surrounding the second power supply terminal 16B. However, if the first chamfered portion 16k and the second chamfered portion 12k are formed discontinuously, the penetration portion 21p may be an open annular ring. The penetration portion 21p contacts and joins the inner circumferential surface of the through hole 12h. Similarly, the penetration portion 21p contacts and joins the outer circumferential surface of the second power supply terminal 16B.

[0062] The intrusion portion 21p surrounds and contacts the outer surface of the second power supply terminal 16B, thereby ensuring a large contact area between the heater electrode 21 and the second power supply terminal 16B. This reduces the connection resistance between the heater electrode 21 and the second power supply terminal 16B. Furthermore, the intrusion portion 21p is positioned between the outer surface of the second power supply terminal 16B and the inner surface of the through hole 12h, and is joined to them, thereby firmly fixing the second power supply terminal 16B to the inner surface of the through hole 12h and preventing the second power supply terminal 16B from detaching from the through hole 12h. In other words, with an electrostatic chuck member 2 having such a configuration, the reliability of the connection between the heater electrode 21 and the second power supply terminal 16B can be increased.

[0063] The depth D of the intrusion portion 21p may be greater than the thickness H of the heater electrode 21, which is positioned between the first ceramic plate 11 and the second ceramic plate 12. By making the depth D of the intrusion portion 21p greater than the thickness H of the heater electrode 21, the contact area with the second power supply terminal 16B at the intrusion portion 21p can be sufficiently widened, and the connection resistance between the heater electrode 21 and the second power supply terminal 16B can be sufficiently reduced. The depth D of the intrusion portion 21p is the dimension in the thickness direction of the intrusion portion 21p, and can be deeper than the chamfer dimensions of the first chamfer portion 16k and the second chamfer portion 12k.

[0064] To ensure a sufficiently deep penetration portion 21p, it is preferable to make the chamfer dimensions of the first chamfer portion 16k and the second chamfer portion 12k larger than the thickness dimension H of the heater electrode 21. Also, to ensure a sufficiently deep penetration portion 21p, for example, the diameter of the through hole 12h may be made 100 μm or more larger than the diameter of the second power supply terminal 16B. In this case, the gap between the outer surface of the second power supply terminal 16B and the inner surface of the through hole 12h can be widened, allowing the penetration portion 21p to penetrate deeply into this gap. However, if this chamfer dimension is made too large, a gap will be created inside the ceramic plate, so it is desirable to set it to an upper limit of about 1000 μm.

[0065] In this specification, the structure of the connection portion between the heater electrode 21 and the second power supply terminal 16B has been described. A similar structure can also be used for the connection portion between the electrostatic adsorption electrode 13 and the first power supply terminal 16A shown in Figure 1. That is, the electrostatic adsorption electrode 13 may have an intrusion portion located between the inner circumferential surface of the through hole 11k of the second plate portion 11b and the outer circumferential surface of the first power supply terminal 16A. By having such an intrusion portion, a wider contact area can be secured between the electrostatic adsorption electrode 13 and the first power supply terminal 16A, thereby improving the reliability of the connection.

[0066] The type of electrode having an intrusion portion is not limited to the heater electrode 21 or the electrostatic adsorption electrode 13, but may also be other electrodes such as an RF (Radio Frequency) electrode.

[0067] (Heater electrodes and insulating portion) As shown in Figure 2, an insulating portion 22 is placed between adjacent heater electrodes 21 to suppress electrical conductivity between the heater electrodes 21. Furthermore, a gap 29 is provided between the insulating portion 22 and the heater electrodes 21. In addition, the side surface 21a of the heater electrode 21 and the side surface 22a of the insulating portion 22 are inclined.

[0068] The heater electrode 21 gradually decreases in width from the upper side (+Z) to the lower side (-Z). Here, the width of the upper end (first end) of the heater electrode 21 is defined as the first width dimension L1, and the width of the lower end (second end) is defined as the second width dimension L2. The first width dimension L1 is greater than the second width dimension L2. L1 > L2

[0069] In this specification, the width dimensions of the heater electrode 21, the insulating portion 22, and the gap 29 refer to the dimensions of the heater electrode 21 in a direction perpendicular to both the thickness direction and the direction in which the heater electrode 21 extends.

[0070] The heater electrode 21 having the cross-sectional shape described above can secure a large contact area between the heater electrode 21 and the first ceramic plate 11 while suppressing the cross-sectional area of ​​the heater electrode 21. The heater electrode 21 can increase its heat generation by reducing its cross-sectional area. Therefore, the heater electrode 21 can increase its heat generation while efficiently transferring the heat generated from the heater electrode 21 to the first ceramic plate 11. As a result, the temperature of the mounting surface 2s can be quickly controlled by the heater electrode 21, and temperature unevenness of the mounting surface 2s can be immediately suppressed.

[0071] Furthermore, as will be described later, the heater electrode 21 is formed by drying and sintering the electrode paste. The electrode paste is dried and sintered after application. The electrode paste shrinks during drying, and its width decreases as it moves away from the application surface in the thickness direction. Therefore, the heater electrode 21 after sintering also decreases in width from one side to the other in the thickness direction. By positioning the side with the larger width dimension upwards, the contact area between the heater electrode 21 and the first ceramic plate 11 can be made larger than the contact area between the heater electrode 21 and the second ceramic plate 12. This makes it easier to transfer heat from the heater electrode 21 to the mounting surface 2s of the first ceramic plate 11.

[0072] In recent electrostatic chuck components, heater electrodes 21 are densely arranged inside the electrostatic chuck component 2. For example, in an electrostatic chuck component 2 with a diameter of 30 cm, the total length of the heater electrodes 21 reaches approximately 900 cm. If the difference between the first width dimension L1 and the second width dimension L2 (L1-L2) is approximately 100 μm, the contact area between the heater electrodes 21 and the first ceramic plate 11 is 9 cm larger than the contact area between the heater electrodes 21 and the second ceramic plate 12. 2The contact area becomes significantly larger. Thus, even a small difference in contact length of about 100 μm in one cross-section of the heater electrode 21 results in a sufficiently large contact area across the entire heater electrode 21. The heater electrode 21 having the shape described above has a significant impact on the temperature controllability of the mounting surface 2s as a whole. As a result, the electrostatic chuck device 1 can significantly improve the temperature controllability of the mounting surface 2s.

[0073] The difference between the first width dimension L1 and the second width dimension L2 (L1 - L2) is preferably greater than or equal to the thickness dimension H of the heater electrode 21 placed between the first ceramic plate 11 and the second ceramic plate 12. L1 - L2 ≥ H

[0074] With this configuration, the heater electrode 21 can have a contact area between the heater electrode 21 and the first ceramic plate 11 that is significantly larger than the contact area between the heater electrode 21 and the second ceramic plate 12. This makes it possible to efficiently transfer heat from the heater electrode 21 to the first ceramic plate 11 while suppressing the cross-sectional area of ​​the heater electrode 21.

[0075] Furthermore, the difference between the first width dimension L1 and the second width dimension L2 (L1-L2) is preferably 10 μm or more and 1000 μm or less. By setting the difference (L1-L2) to 10 μm or more, it is possible to suppress the cross-sectional area of ​​the heater electrode 21 while making it easier to transfer heat to the first ceramic plate 11, and effectively suppressing temperature unevenness on the mounting surface 2s.

[0076] On the other hand, if the difference (L1-L2) exceeds 1000 μm, it becomes difficult to secure a sufficient contact area between the heater electrode 21 and the second ceramic plate 12. The first ceramic plate 11 is supported by the second ceramic plate 12 via the heater electrode 21 and the insulating portion 22. Therefore, if the contact area between the heater electrode 21 and the second ceramic plate 12 becomes too small, the first ceramic plate 11 may not be adequately supported, and there is a risk of the first ceramic plate 11 bending. By keeping the difference (L1-L2) of the heater electrode 21 to 1000 μm or less, bending of the first ceramic plate 11 can be suppressed.

[0077] As shown in Figure 2, the width of the insulating portion 22 gradually decreases from the bottom (-Z) to the top (+Z). Here, the width of the upper end (first end) of the insulating portion 22 is defined as the third width dimension L3, and the width of the lower end (second end) is defined as the fourth width dimension L4. The third width dimension L3 may be smaller than the fourth width dimension L4. L3 < L4

[0078] Here, the width dimension of the upper end of the insulating portion 22 refers to the width dimension of the insulating portion 22 along the extension line of the upper end surface of the heater electrode 21. Similarly, the width dimension of the lower end of the insulating portion 22 refers to the width dimension of the insulating portion 22 along the extension line of the lower end surface of the heater electrode 21.

[0079] In an electrostatic chuck member 2 having such an insulating portion 22, the side surface 22a of the insulating portion 22 can be inclined in a direction substantially parallel to the side surface 21a of the opposing heater electrode 21. This allows the heater electrode 21 and the insulating portion 22 to be brought closer together, making it possible to precisely arrange the heater electrode 21 and the insulating portion 22. By precisely arranging the heater electrode 21 and the insulating portion 22, it becomes easier to reduce temperature unevenness on the mounting surface 2s by the heater electrode 21.

[0080] The insulating paste is dried and sintered after application. The insulating paste shrinks during drying, and its width decreases as it moves away from the application surface in the thickness direction. Therefore, the insulating portion 22 after sintering also decreases in width from one side to the other in the thickness direction. The insulating portion 22 formed in this way can be positioned so that the side surface 22a of the insulating portion 22 is separated from the side surface 21a of the heater electrode 21 along its entire thickness direction by making the side with the larger width of the insulating portion 22 the lower side, which is the side with the smaller width of the heater electrode 21. This makes it possible to precisely position the heater electrode 21 and the insulating portion 22 while ensuring sufficient distance between them.

[0081] The difference between the third width dimension L3 and the fourth width dimension L4 (L4-L3) is more preferably 10 μm or more and 1000 μm or less, similar to the difference between the first width dimension L1 and the second width dimension L2 (L1-L2). This suppresses conductivity between adjacent heater electrodes 21 while suppressing the deflection of the first ceramic plate 11. Furthermore, by setting the difference between the third width dimension L3 and the fourth width dimension L4 (L4-L3) and the difference between the first width dimension L1 and the second width dimension L2 (L1-L2) to approximately the same value, it becomes possible to further increase the installation density of the heater electrodes 21.

[0082] The ratio of the difference between the first width dimension L1 and the second width dimension L2 (L1-L2) to the difference between the third width dimension L3 and the fourth width dimension L4 (L4-L3) is preferably 0.7 or more and 1.3 or less. 0.7 ≤ (L1-L2) / (L4-L3) ≤ 1.3

[0083] When this ratio ((L1-L2) / (L4-L3)) is 1, the heater electrodes 21 and the insulating part 22 can be arranged most densely. Furthermore, if the above ratio is in the range of 0.7 to 1.3, the heater electrodes 21 and the insulating part 22 can be arranged sufficiently densely, and the temperature unevenness of the mounting surface 2s can be sufficiently reduced.

[0084] The side surface 21a of the heater electrode 21 and the side surface 22a of the insulating portion 22 may face each other with a gap 29 in between. In an electrostatic chuck member 2 with such a configuration, an air layer can be provided between the heater electrode 21 and the insulating portion 22, thereby improving the insulation performance between the heater electrodes 21. Furthermore, it becomes easier to suppress the mixing of these components during the molding of the heater electrode 21 and the insulating portion 22, making it easier to ensure the insulation performance of the insulating portion 22.

[0085] The width dimension of the gap 29 is defined as the fifth width dimension L5. Preferably, the fifth width dimension L5 is greater than or equal to the thickness dimension H of the heater electrode 21, which is placed between the first ceramic plate 11 and the second ceramic plate 12, and less than or equal to the fourth width dimension L4. H ≤ L5 ≤ L4

[0086] By making the fifth width dimension L5 greater than or equal to the thickness dimension H of the heater electrode 21, the heater electrode 21 and the insulating part 22 can be reliably separated by the gap 29, and the insulation performance between the heater electrodes 21 can be sufficiently improved. On the other hand, if the fifth width dimension L5 is made too wide, the distance between the heater electrodes 21 becomes too wide, and the temperature controllability of the mounting surface 2s decreases. Therefore, by making the fifth width dimension L5 less than or equal to the fourth width dimension L4, the heater electrodes 21 can be arranged more densely, making it easier to reduce temperature unevenness on the mounting surface 2s.

[0087] Note that the fifth width dimension L5 is not necessarily constant throughout the entire thickness direction of the gap 29. At any position in the thickness direction, the fifth width dimension L5 should be greater than or equal to the thickness dimension H of the heater electrode 21 and less than or equal to the fourth width dimension L4.

[0088] (Method for manufacturing electrostatic chuck member) The electrostatic chuck member 2 is manufactured as follows, as an example. Figure 3 is a flowchart of the method for manufacturing the electrostatic chuck member 2. The method for manufacturing the electrostatic chuck member 2 includes a through-hole forming step S10, a first coating step S20, a second coating step S30, a drying step S40, a lamination step S50, an insertion step S60, and a sintering step S70.

[0089] Figure 4 is a schematic diagram showing the manufacturing process of the electrostatic chuck member 2 up to the lamination process S50. The through-hole formation process S10 is a process of forming a through-hole 12h in the second ceramic plate 12. The through-hole formation process S10 is performed before the first coating process S20, the second coating process S30, and the drying process S40. However, the through-hole formation process S10 may be performed at any time before the lamination process S50.

[0090] In the through-hole formation step S10, the through-hole 12h is formed, for example, by machining the second ceramic plate 12 with a diamond drill. Alternatively, the through-hole 12h may be formed by laser processing, electrical discharge machining, ultrasonic processing, or the like.

[0091] The first coating step S20 is a step of applying electrode paste 211 in a strip shape to the first opposing surface (first coating surface) 11f of the first ceramic plate 11. In the first coating step S20, a pattern of electrode paste 211 is formed on the first opposing surface 11f using a printing method such as screen printing. This pattern has a shape that corresponds to the pattern shape of the heater electrode 21 in a plan view.

[0092] The electrode paste 211 can be made from any known material as long as it can form the heater electrode 21. The electrode paste 211 may, for example, contain a conductive material, ceramic powder, a binder, and a solvent.

[0093] Examples of conductive materials include tungsten, tungsten carbide, platinum, silver, palladium, nickel, and molybdenum.

[0094] Examples of ceramic powders include powders made from the same type of ceramic material as the materials constituting the first ceramic plate 11 and the second ceramic plate 12.

[0095] Examples of binders include ethylcellulose, polymethyl methacrylate, and polyvinyl butyral. Examples of solvents include terpineol.

[0096] The second coating step S30 is a step of applying insulating paste 221 to the second opposing surface (second coating surface) 12f of the second ceramic plate 12. In the second coating step S30, a printing method such as screen printing is used to form a pattern of insulating paste 221 on the second opposing surface 12f. The electrode paste 211 and the insulating paste 221 are provided complementaryly between the first ceramic plate 11 and the second ceramic plate 12. In addition, the insulating paste 221 is provided in a position that avoids the opening of the through hole 12h.

[0097] The insulating paste 221 may, for example, contain insulating ceramic powder, a binder, and a solvent. Examples of insulating ceramic powder include the powder of the material described above as the material for the insulating part 22. The binder and solvent of the insulating paste 221 can be the same materials used in the electrode paste 211 described above.

[0098] The first coating step S20 and the second coating step S30 may be performed at any time before the drying step S40. For example, the first coating step S20 and the second coating step S30 may be performed before the through-hole forming step S10, or the second coating step S30 may be performed before the first coating step S20.

[0099] The drying step S40 is a step in which the electrode paste 211 is dried to form the first precursor 212 of the heater electrode 21, and the insulating paste 221 is dried to form the second precursor 222 of the insulating part 22.

[0100] The cross-sectional shape of the first precursor 212 formed in drying step S40 is a roughly trapezoidal shape, with the width decreasing towards the bottom. On the other hand, the cross-sectional shape of the second precursor 222 formed in drying step S40 is a roughly trapezoidal shape, with the width decreasing towards the top. In other words, drying step S40 is a step in which the electrode paste 211 is shrunk so that its width decreases as it moves away from the first opposing surface 11f, and the insulating paste 221 is shrunk so that its width decreases as it moves away from the second opposing surface 12f.

[0101] The roughly trapezoidal first precursor 212 and second precursor 222 can be formed by drying the paste in a high-temperature environment for a short period of time, for example, by drying it at 90°C for 30 minutes, instead of the usual drying conditions of 30°C for 6 hours.

[0102] Figure 5 is a schematic diagram showing the manufacturing process of the electrostatic chuck member 2 from the lamination process S50 onwards. The lamination process S50 is a process in which the first ceramic plate 11 is stacked on the second ceramic plate 12 with the first opposing surface 11f facing the second ceramic plate 12. In the through-hole formation process S10, the through-hole 12h is formed in a position that overlaps with the electrode paste 211 applied in the first coating process S20. Therefore, by laminating the first ceramic plate 11 and the second ceramic plate 12 in the lamination process S50, the first precursor 212 (i.e., the dried electrode paste 211) is exposed from the through-hole 12h.

[0103] Insertion step S60 is the step of inserting the second power supply terminal 16B into the through hole 12h and bringing it into contact with the first precursor 212 (i.e., the dried electrode paste 211). The end face of the second power supply terminal 16B is pressed against the electrode paste 211. As a result, a portion of the electrode paste 211 penetrates into the gap between the inner circumferential surface of the through hole 12h and the outer circumferential surface of the second power supply terminal 16B.

[0104] Sintering step S70 is a step in which the first precursor 212 and the second precursor 222 are sintered. Sintering step S70 is a step in which the first ceramic plate 11 and the second ceramic plate 12 are joined and integrated by hot pressing at a temperature of 1400°C to 1900°C in a non-oxidizing atmosphere while applying pressure of 1 MPa to 50 MPa in the thickness direction.

[0105] As shown in Figure 2, through the sintering process S70, the first precursor 212 becomes the heater electrode 21, and the second precursor 222 becomes the insulating portion 22. The first ceramic plate 11, the second ceramic plate 12, and the second power supply terminal 16B are joined together by the heater electrode 21 and the insulating portion 22, forming a single unit. A portion of the electrode paste 211 is sintered while penetrating the gap between the inner surface of the through hole 12h and the outer surface of the second power supply terminal 16B, forming an intrusion portion 21p.

[0106] In conventional manufacturing methods, through-holes 12h were formed after the lamination process S50. In this case, it was difficult to adjust the drilling depth so that the tip of the through-hole 12h aligned with one surface of the thin-film heater electrode 21. Furthermore, there was a concern that processing residue could get stuck between the heater electrode 21 and the second power supply terminal 16B, increasing the connection resistance.

[0107] In contrast, according to the manufacturing method of the electrostatic chuck member of this embodiment, the through-hole formation step S10 is performed before the lamination step S50. With this manufacturing method, it is not necessary to form the through-hole 12h in the second ceramic plate 12 in advance before performing the lamination step S50 and to precisely adjust the depth of the through-hole 12h. Therefore, problems such as damage to the heater electrode 21 or an increase in the connection resistance between the heater electrode 21 and the second power supply terminal 16B can be suppressed in the through-hole formation step S10. As a result, an electrostatic chuck member 2 with improved reliability of the connection between the heater electrode 21 and the second power supply terminal 16B can be manufactured.

[0108] Furthermore, in the electrostatic chuck member 2, a through hole 12h is formed in the second ceramic plate 12. Therefore, when applying electrode paste 211 to the second ceramic plate 12, the electrode paste 211 flows into the inner circumferential surface of the through hole 12h, making it impossible to apply the electrode paste 211 with a uniform film thickness.

[0109] In contrast, according to the manufacturing method described above, in the first coating step S20, the electrode paste 211 is applied to the first opposing surface 11f of the first ceramic plate 11. By applying the electrode paste 211 to the first ceramic plate 11 in which no through holes 12h are formed, an electrode paste 211 with a uniform film thickness can be formed.

[0110] Furthermore, in order to prevent the electrode paste 211 from flowing into the through hole 12h, it is also possible to apply the electrode paste 211 to the second ceramic plate 12 after inserting the second power supply terminal 16B into the through hole 12h. In this case, even if the second opposing surface 12f is polished with the second power supply terminal 16B inserted, a minute step will remain between the second opposing surface 12f and the second power supply terminal 16B. For this reason, even if the electrode paste 211 is applied after inserting the second power supply terminal 16B into the through hole 12h, it is difficult to apply the electrode paste 211 uniformly.

[0111] According to the manufacturing method described above, in the drying step S40, the electrode paste 211 (i.e., the first precursor 212) after drying can be shrunk so that its width decreases as it moves away from the first opposing surface 11f. As a result, the area of ​​the heater electrode 21 in contact with the first opposing surface 11f can be made larger than the area of ​​contact with the second opposing surface 12f.

[0112] According to the manufacturing method described above, the insulating paste 221 is applied to the second opposing surface 12f of the second ceramic plate 12 in the second coating step S30, and then dried in the drying step S40. As a result, the insulating paste 221 (i.e., the second precursor 222) after drying can be shrunk so that its width decreases as it moves away from the second opposing surface 12f. This allows the side surface 22a of the insulating part 22 to be inclined in the same direction as the side surface 21a of the heater electrode 21 after sintering, and the insulating part 22 and the heater electrode 21 to be brought close together and the heater electrode 21 to be densely arranged while securing a gap 29 between the insulating part 22 and the heater electrode 21.

[0113] In the lamination process S50, the upper and lower ends of the first precursor 212 and the second precursor 222 are compressed and spread in the width direction. At this time, if the first precursor 212 and the second precursor 222 are too close together, the first precursor 212 and the second precursor 222, which are spreading in the width direction, may mix with each other, potentially reducing the insulating properties of the insulating portion 22.

[0114] In contrast, in the manufacturing method of this embodiment described above, the electrode paste 211 and the insulating paste 221 are applied to the opposing surfaces (first opposing surface 11f and second opposing surface 12f) of the ceramic plates facing each other. The paste applied in a strip shape on each surface shrinks as it dries, reducing its width as it moves away from the surface. In the position where the ceramic plates on which the first precursor 212 and the second precursor 222 are formed are facing each other, the first precursor 212 has a larger upper width and a smaller lower width, while the second precursor 222 has a smaller upper width and a larger lower width.

[0115] Therefore, the sides of the first precursor 212 and the second precursor 222, which face each other, can be tilted in a direction that is approximately parallel to each other. This allows the upper end of the first precursor 212 to be positioned away from the upper end of the second precursor 222, and the lower end of the first precursor 212 to be positioned away from the lower end of the second precursor 222. As a result, even if the upper and lower ends of the first precursor 212 and the second precursor 222 spread out in the width direction, mixing of these parts with each other can be suppressed, and electrical conductivity between adjacent heater electrodes 21 can be suppressed.

[0116] The insertion step S60 is performed after the lamination step S50. Therefore, in the insertion step S60, the tip surface of the second power supply terminal 16B can be sufficiently pressed against the electrode paste 211, and the remaining gap between the second power supply terminal 16B and the electrode paste 211 can be suppressed. In contrast, if the lamination step S50 is performed with the second power supply terminal 16B inserted into the through hole 12h, there is a risk that a gap will remain between the electrode paste 211 and the second power supply terminal 16B. According to the manufacturing method of this embodiment, the reliability of the connection between the second power supply terminal 16B and the electrode paste 211 can be improved.

[0117] Figure 6 is a photograph of the cross-section of the heater electrode 21 and the insulating portion 22 in the electrostatic chuck member 2. As shown in Figure 6, it was confirmed that the side surface 21a of the heater electrode 21 and the side surface 22a of the insulating portion 22 are inclined in a direction that is substantially parallel to each other. Furthermore, it was confirmed that the side surface 21a of the heater electrode 21 and the side surface 22a of the insulating portion 22 face each other with a gap 29 in between.

[0118] Figure 7 is a photograph of the cross-section of the heater electrode 21 and the second power supply terminal 16B in the electrostatic chuck member 2. As shown in Figure 7, it was confirmed that the entry portion 21p enters the gap between the inner circumferential surface of the through hole 12h and the outer circumferential surface of the second power supply terminal 16B when using the electrostatic chuck member 2.

[0119] <Second Embodiment> Figure 8 is an enlarged cross-sectional view of the electrostatic chuck member 102 of the second embodiment, and is a cross-sectional view perpendicular to the direction in which the heater electrode 121 extends. The electrostatic chuck member 102 differs from the embodiment described above mainly in the material of the heater electrode 121. In the description of this embodiment, components that are the same as those in the embodiment described above are denoted by the same reference numerals and their descriptions are omitted. Also, the definitions of the first width dimension L1 to the fourth width dimension L4 in this embodiment are the same as in the embodiment described above.

[0120] (Electrostatic Chuck Member) The electrostatic chuck member 102 includes a first ceramic plate (first substrate) 111, a second ceramic plate (second substrate) 112, a heater electrode 121, and a bonding layer 128. The heater electrode 121 is located between the first ceramic plate 111 and the second ceramic plate 112. The heater electrode 121 is arranged in a groove 115 provided in the second ceramic plate 112. Similar to the embodiment described above, the heater electrode 121 is strip-shaped.

[0121] The heater electrode 121 is made of a resistance heating material and generates heat when an electric current flows through it. The heater electrode 121 is manufactured by processing a non-magnetic metal sheet, such as an Inconel® sheet, a titanium sheet, a tungsten (W) sheet, or a molybdenum (Mo) sheet, into a desired heater shape by etching or laser processing. The heater shape can be, for example, a strip-shaped conductive sheet that is meandering, with an overall contour being annular. The heater electrode 121 is arranged in a meandering manner between the first ceramic plate 111 and the second ceramic plate 112. Although not shown in the figures, similar to the embodiment described above, second power supply terminals 16B (see Figure 1) are connected to both ends of the heater electrode 121 in the longitudinal direction.

[0122] In the electrostatic chuck member 102, the heater electrode 121 is made of a thin metal plate. Compared to the case in which a composite of an insulating material and a conductive material is used as the heater electrode, as in the electrostatic chuck member 2 of the first embodiment, the electrostatic chuck member 102 allows a large current to be passed through the heater electrode 121, enabling precise temperature control of the wafer W over a wide range from low to high temperatures.

[0123] Similar to the embodiment described above, the heater electrode 121 gradually decreases in width from the upper side (+Z) to the lower side (-Z). The first width dimension L1 is larger than the second width dimension L2 (L1 > L2). The heater electrode 121 allows for a wide contact area between the heater electrode 121 and the bonding layer 128 between the heater electrode 121 and the first ceramic plate 111, while suppressing the cross-sectional area of ​​the heater electrode 121. This makes it easier to quickly control the temperature of the wafer W with the heater electrode 121, and to immediately suppress temperature unevenness in the wafer W.

[0124] Furthermore, the electrostatic chuck member 102 has a bonding layer 128 between the heater electrode 121 and the first ceramic plate 111. Therefore, in the electrostatic chuck member 102, the heater electrode 121 and the first ceramic plate 111 are not in direct contact, but are adjacent to each other via the bonding layer 128.

[0125] The bonding layer 128 is sufficiently thin compared to the first ceramic plate 111 and the second ceramic plate 112. Furthermore, the bonding layer 128 can be made of a material with sufficiently high thermal conductivity that does not hinder heat transfer between the heater electrode 121 and the first ceramic plate 111. For this reason, it is considered that the presence of the bonding layer 128 can be ignored when considering heat transfer between the heater electrode 121 and the first ceramic plate 111.

[0126] In other words, when heating the first ceramic plate 111 using the heater electrode 121, the heat generated by the heater electrode 121 is thought to be quickly transferred in the thickness direction, and there is no need to consider diffusion in the planar direction in the bonding layer 128. For this reason, in a configuration where the heater electrode 121 and the first ceramic plate 111 are in direct contact, the area A over which the heater electrode 121 heats the first ceramic plate 111 is considered to be approximately the same as the area B over which the heater electrode 121 heats the first ceramic plate 111 in a configuration where the bonding layer 128 is interposed between the heater electrode 121 and the first ceramic plate 111 (A ≈ B).

[0127] Therefore, in the following explanation, the contact area between the heater electrode 121 and the bonding layer 128 will simply be referred to as the "contact area between the heater electrode 121 and the first ceramic plate 111".

[0128] Similar to the first embodiment, it is preferable that the difference between the first width dimension L1 and the second width dimension L2 (L1-L2) is greater than or equal to the thickness dimension H of the heater electrode 121 positioned between the first ceramic plate 111 and the second ceramic plate 112 (L1-L2≧H). In this case, the contact area between the heater electrode 121 and the first ceramic plate 111 can be made sufficiently larger than the contact area between the heater electrode 121 and the second ceramic plate 112, making it possible to efficiently transfer heat from the heater electrode 121 to the first ceramic plate 111 while suppressing the cross-sectional area of ​​the heater electrode 121.

[0129] In the electrostatic chuck member 102, a first region 121t and a second region 121k are provided on the side surface 121a of the heater electrode 121. The first region 121t and the second region 121k are arranged side by side in the thickness direction. The first region 121t is located at the upper (+Z) end of the side surface 121a. That is, the first region 121t is connected to the bonding layer 128 located above the heater electrode 121. The second region 121k is located below the first region 121t. The upper (+Z) end of the second region 121k is connected to the lower (-Z) end of the first region 121t.

[0130] The first region 121t is inclined at a first angle α with respect to the thickness direction. Here, the first angle α is an angle in which the inclination towards the inside of the width direction of the heater electrode 121 as it moves upward (+Z) is considered positive. In the electrostatic chuck member 102, the first angle α is an angle of 0° or more. Note that if the first angle α is 0°, the first region 121t extends parallel to the thickness direction. That is, in the electrostatic chuck member 102, the first region 121t may be a region that extends parallel to the thickness direction.

[0131] In this specification, the width direction of the heater electrode 121 is the direction perpendicular to both the extending direction and the thickness direction of the heater electrode 121. Furthermore, the inner side in the width direction of the heater electrode 121 is the side of the heater electrode 121 that is closer to the center of the heater electrode 121 in the width direction. Moreover, the outer side in the width direction of the heater electrode 121 is the side of the heater electrode 121 that is further away from the center of the heater electrode 121 in the width direction.

[0132] The first region 121t may extend at a constant first angle α throughout, or the first angle α may change continuously or stepwise along the thickness direction. The first region 121t is a curved surface in which the first angle α continuously increases as it moves upward.

[0133] The second region 121k is inclined at a second angle β with respect to the thickness direction. Here, the second angle β is an angle in which the inclination toward the outside in the width direction of the heater electrode 121 is considered positive as it moves upward (+Z). In the electrostatic chuck member 102, the second angle β is an angle greater than 0°. That is, the second region 121k is inclined at a second angle β greater than 0° in the direction toward the outside in the width direction of the heater electrode 121 as it moves upward. The second region 121k may be inclined at a constant second angle β throughout, or the second angle β may be changed continuously or stepwise along the thickness direction.

[0134] The thickness dimension of the second region 121k is sufficiently larger than the thickness dimension of the first region 121t. The heater electrode 121 is tilted outward in the width direction as the second region 121k of the side surface 121a moves upward, so the overall width dimension gradually increases from bottom to top, and the first width dimension L1 is larger than the second width dimension L2.

[0135] The heater electrode 121 has a first region 121t at the upper end of the side surface 121a of the heater electrode 121, which is inclined at a first angle α of 0° or more in the direction toward the inside in the width direction of the heater electrode 121 as it moves upward. Here, if the side surface 121a of the heater electrode 121 has only a second region 121k, the thermal conductivity to the first ceramic plate 111 tends to decrease at the outer end of the heater electrode 121 in the width direction. This is because the outer end of the upper end surface (second surface 121d, described later) of the heater electrode 121 does not receive heat from the outside in the width direction, so its temperature is lower than other parts. Therefore, it is conceivable to increase the first width dimension L1 of the upper end of the heater electrode 121, but in this case, there is a risk that the leakage current through the bonding layer 128 between adjacent heater electrodes 121 in the width direction will increase.

[0136] In contrast, the heater electrode 121 has a first region 121t at the upper end of the side surface 121a of the heater electrode 121 that slopes inward in the width direction as it extends upward. When the first angle α exceeds 0°, the heater electrode 121 has a portion 121x that protrudes further outward in the width direction than the width direction end of the upper end surface. In Figure 8, the portion corresponding to reference numeral 121x is enclosed by a dashed line. In a heater electrode 121 with this configuration, heat is supplied to the width direction end of the upper end surface of the heater electrode 121 from the protruding portion 121x as well, making it difficult for the temperature of the width direction end to drop.

[0137] Furthermore, when the first angle α is 0°, a portion of the heater electrode 121 is also positioned below the widthwise end of the upper end surface. In this configuration, heat is supplied from the portion of the heater electrode 121 located below the widthwise end of the upper end surface of the heater electrode 121, making it difficult for the temperature of the widthwise end to drop.

[0138] For these reasons, the electrostatic chuck member 102 makes it possible to uniformly transfer heat from the heater electrode 121 to the first ceramic plate 111. Furthermore, the electrostatic chuck member 102 makes it possible to secure a distance between the upper ends of adjacent heater electrodes 121 at the upper end of the heater electrode 121, thereby suppressing an increase in leakage current through the bonding layer 128.

[0139] The first angle α is effective when it is 0° or greater, but it is more preferable when the angle exceeds 0°. In this case, the uniformity of heating at the upper end of the heater electrode 121 can be further improved.

[0140] Furthermore, in this embodiment, the case in which only the first region 121t and the second region 121k are provided on the side surface 121a of the heater electrode 121 has been described. However, other regions with different inclination angles with respect to the thickness direction may be provided on the side surface 121a of the heater electrode 121. For example, a third region different from the first region 121t and the second region 121k may be provided in the thickness direction.

[0141] An insulating portion 122 is provided between adjacent heater electrodes 121 between the first ceramic plate 111 and the second ceramic plate 112. The insulating portion 122 is integrally provided with the second ceramic plate 112. The insulating portion 122 is a region located between grooves 115 provided in the second ceramic plate 112. The insulating portion 122 may be made of a different material from the first ceramic plate 111 and the second ceramic plate 112, as long as it is located between the heater electrodes 121 and can ensure insulation between the heater electrodes 121.

[0142] Similar to the embodiment described above, the width of the insulating portion 122 gradually decreases from the bottom (-Z) to the top (+Z). The third width dimension L3 is smaller than the fourth width dimension L4 (L3 < L4). The electrostatic chuck member 102 allows the side surface 122a of the insulating portion 122 to be tilted in a direction substantially parallel to the side surface 121a of the opposing heater electrode 121. This brings the heater electrode 121 and the insulating portion 122 closer together, making it possible to precisely arrange the heater electrode 121 and the insulating portion 122. By precisely arranging the heater electrode 121 and the insulating portion 122, it becomes easier to reduce temperature unevenness in the wafer W by the heater electrode 121.

[0143] Similar to the first embodiment, the ratio of the difference between the first width dimension L1 and the second width dimension L2 (L1-L2) to the difference between the third width dimension L3 and the fourth width dimension L4 (L4-L3) is preferably 0.7 or more and 1.3 or less. 0.7 ≤ (L1-L2) / (L4-L3) ≤ 1.3

[0144] When this ratio ((L1-L2) / (L4-L3)) is 1, the heater electrodes 121 and the insulating portion 122 can be arranged most densely. Furthermore, if the above ratio is in the range of 0.7 to 1.3, the heater electrodes 121 and the insulating portion 122 can be arranged sufficiently densely, and the temperature unevenness of the wafer W can be sufficiently reduced.

[0145] In the electrostatic chuck member 102, the side surface 121a of the heater electrode 121 and the side surface 122a of the insulating portion 122 face each other with a gap 129 in between. The electrostatic chuck member 102 allows for the creation of an air layer between the heater electrode 121 and the insulating portion 122, thereby improving the insulation performance between the heater electrodes 121.

[0146] Furthermore, even when the heater electrode 121, which is made of a thin metal plate, is in contact with the insulating part 122, the constituent components do not mix with each other, making it easy to ensure insulation. Therefore, the heater electrode 121 can be placed close to the insulating part 122, making it easier to arrange the heater electrodes 121 densely.

[0147] The bonding layer 128 is placed between the first ceramic plate 111 and the insulating portion 122 of the second ceramic plate 112. The bonding layer 128 bonds the first ceramic plate 111 and the second ceramic plate 112. The bonding layer 128 also bonds the first ceramic plate 111 and the heater electrode 121.

[0148] The bonding layer 128 is made of an insulating material. Therefore, even when the bonding layer 128 is brought into contact with the heater electrode 121, no current flows through the bonding layer 128. As the insulating material constituting the bonding layer 128, for example, high-purity alumina (Al ２ O ３ ) and the like can be suitably adopted.

[0149] (Method for manufacturing electrostatic chuck member) The electrostatic chuck member 102 is manufactured as follows, for example. Figure 9 is a flowchart showing the method for manufacturing the electrostatic chuck member 102. The method for manufacturing the electrostatic chuck member 102 includes an electrode formation step S110, a groove formation step S120, a lamination step S150, and a sintering step S170.

[0150] The electrode formation step S110 is a step in which a plate-shaped metal material is cut by etching or laser processing to form a strip-shaped heater electrode. Figure 10 is a schematic diagram showing an electrode formation step S110 by etching, which is one example of this embodiment. Figure 11 is a schematic diagram showing an electrode formation step S110 by laser processing, which is another example of this embodiment.

[0151] As shown in Figure 10, the metal plate 121P has a first surface 121c and a second surface 121d. In the electrode formation process S110 in Figure 10, first, a mask M is formed on the first surface 121c of the plate 121P. The mask M has approximately the same shape as the heater electrode 121.

[0152] Next, with the plate material 121P mounted on the base B, etching is performed on the plate material 121P from the first surface 121c side, and the portion of the plate material 121P exposed from the mask M is etched to cut the plate material 121P and form a strip-shaped heater electrode 121. After the heater electrode 121 is formed, the mask M is removed. The side surface 121a of the heater electrode 121 formed by the etching process becomes an inclined surface. More specifically, the width dimension of the heater electrode 121 increases from the first surface 121c side to the second surface 121d side.

[0153] In the electrode formation process S110 shown in Figure 10, a first region 121t is formed at the corner between the side surface 121a and the second surface 121d of the heater electrode 121. When etching is performed, some of the etching solution enters the small gap between the second surface 121d of the heater electrode 121 and the base B. As a result, etching progresses on the outer edge in the width direction of the second surface 121d of the heater electrode 121, and the first region 121t is formed.

[0154] In the electrode formation process S110 shown in Figure 11, with the plate material 121P mounted on the base B, the plate material 121P is cut by irradiating it with laser light L from the first surface 121c side to form a strip-shaped heater electrode 121. The side surface 121a of the heater electrode 121 formed by laser processing becomes an inclined surface. More specifically, the width dimension of the heater electrode 121 increases from the first surface 121c side, which is the side irradiated with laser light L, to the second surface 121d side.

[0155] The groove formation step S120 is a step in which grooves 115 are formed on the second opposing surface 112f of the second ceramic plate 112. The grooves 115 are formed by methods such as milling, laser processing, or sandblasting. Note that the groove formation step S120 may be performed before the electrode formation step S110.

[0156] As shown in Figure 8, the groove 115 is formed such that its width increases as it moves upward. That is, the width of the opening of the groove 115 is greater than the width of the bottom of the groove 115. The width of the bottom of the groove 115 is greater than the width of the first surface 121c of the heater electrode 121. Also, the width of the opening of the groove 115 is greater than the width of the second surface 121d of the heater electrode 121.

[0157] Figure 12 is a schematic diagram showing the lamination process S150. The lamination process S150 is a process of laminating a first ceramic plate 111 and a second ceramic plate 112 with a heater electrode 121 sandwiched in between. In the lamination process S150, the heater electrode 121 is positioned inside the groove 115. Also, in the lamination process S150, the first surface 121c is positioned facing downwards in the thickness direction. As a result, the side surface 121a of the heater electrode 121 and the side surface 122a of the insulating portion 122 face each other.

[0158] In the lamination process S150, first, an unsintered paste-like bonding layer 128 is applied to the first opposing surface 111f of the first ceramic plate 111. The procedure for applying the bonding layer 128 paste to the first opposing surface 111f may be carried out using a brush, spatula, trowel, etc., or by screen printing.

[0159] Next, the first opposing surface 111f is placed against the second opposing surface 112f of the second ceramic plate 112, which has the heater electrode 121 positioned in the groove 115, and the first ceramic plate 111 and the second ceramic plate 112 are stacked in the thickness direction.

[0160] Next, the first ceramic plate 111 and the second ceramic plate 112 are hot-pressed together under high temperature and high pressure. Through this process, the bonding layer 128 is bonded to the entire surface of the first opposing surface 111f. The bonding layer 128 is also bonded to the upper surface of the insulating portion 122 and the upper surface of the heater electrode 121 on the second opposing surface 112f.

[0161] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but the present invention is not limited to these examples. The shapes and combinations of the constituent members shown in the above examples are merely examples, and can be modified in various ways based on design requirements, etc., without departing from the spirit of the present invention.

[0162] For example, in the above-described embodiment, the heater electrode 21 was described in a case where both sides in the width direction are inclined, but the inclination shape of both sides is not limited as long as the first width dimension L1 and the second width dimension L2 satisfy the above-described relationship. Similarly, in the above-described embodiment, the insulating portion 22 was described in a case where both sides in the width direction are inclined, but the inclination shape of both sides is not limited as long as the third width dimension L3 and the fourth width dimension L4 satisfy the above-described relationship.

[0163] 1...Electrostatic chuck device, 2, 102...Electrostatic chuck member, 3, B...Base, 11f...First opposing surface (first coating surface), 11k, 12d, 12h...Through hole, 12f...Second opposing surface (second coating surface), 21, 121...Heater electrode, 21a, 22a, 121a, 122a...Side, 21p...Intrusion part, 22, 122...Insulating part, 29, 129...Gap, 121t...First region, 121k...Second region, 115...Groove, 121c...First surface, 211...For electrode Paste, 221...Insulating paste, H...Thickness dimension, L1...First width dimension, L2...Second width dimension, L3...Third width dimension, L4...Fourth width dimension, S10...Through hole formation process, S20...First coating process, S30...Second coating process, S40...Drying process, S50, S150...Lamination process, S60...Insertion process, S70, S170...Sintering process, S110...Electrode formation process, S120...Groove formation process, W...Wafer (plate-shaped sample), α...First angle, β...Second angle

Claims

1. An electrostatic chuck member for mounting a plate-shaped sample, comprising: a first substrate and a second substrate stacked in the thickness direction; and a layered heater electrode provided between the first substrate and the second substrate, wherein the heater electrode is strip-shaped and forms a predetermined pattern when viewed from the thickness direction, the first substrate side is designated as the first side and the second substrate side as the second side in the thickness direction, the plate-shaped sample is mounted on the first side relative to the heater electrode, and the first width dimension of the first side end of the heater electrode is greater than the second width dimension of the second side end of the heater electrode.

2. The electrostatic chuck member according to claim 1, wherein the difference between the first width dimension and the second width dimension is greater than or equal to the thickness dimension of the heater electrode disposed between the first substrate and the second substrate.

3. An insulating portion is provided between adjacent heater electrodes between the first substrate and the second substrate, and the third width dimension of the first end of the insulating portion is smaller than the fourth width dimension of the second end of the insulating portion, according to claim 1.

4. The electrostatic chuck member according to claim 3, wherein the ratio of the difference between the first width dimension and the second width dimension to the difference between the third width dimension and the fourth width dimension is 0.7 or more and 1.3 or less.

5. The electrostatic chuck member according to claim 3, wherein the side surface of the heater electrode and the side surface of the insulating portion face each other with a gap in between.

6. The electrostatic chuck member according to claim 5, wherein the width dimension of the gap is greater than or equal to the thickness dimension of the heater electrode disposed between the first substrate and the second substrate, and less than or equal to the fourth width dimension.

7. The electrostatic chuck member according to claim 3, wherein the resistivity of the material constituting the insulating portion is greater than the resistivity of the materials constituting the first substrate and the second substrate.

8. The electrostatic chuck member according to claim 1, comprising a power supply terminal for supplying power to the heater electrode, wherein the second substrate is provided with a through hole that penetrates in the thickness direction and into which the power supply terminal is inserted, and the heater electrode has an intrusion portion located between the inner circumferential surface of the through hole and the outer circumferential surface of the power supply terminal.

9. The electrostatic chuck member according to claim 8, wherein the dimension of the penetration portion in the thickness direction is greater than the thickness dimension of the heater electrode disposed between the first substrate and the second substrate.

10. The electrostatic chuck member according to claim 1, wherein the side surface of the heater electrode has a first region located at the first end and a second region located to the second side of the first region, the first region is inclined at an angle of 0° or more in the direction toward the inside in the width direction of the heater electrode as it approaches the first side, and the second region is inclined at an angle greater than 0° in the direction toward the outside in the width direction of the heater electrode as it approaches the first side.

11. The electrostatic chuck member according to claim 1, wherein the heater electrode is made of a thin metal plate.

12. An electrostatic chuck device comprising an electrostatic chuck member according to any one of claims 1 to 11, and a base for cooling the electrostatic chuck member and adjusting the temperature of the electrostatic chuck member.

13. A method for manufacturing an electrostatic chuck member for mounting a plate-shaped sample on a first side in the thickness direction, comprising: a first coating step of applying an electrode paste in a strip shape to a first coated surface of a first substrate; a drying step of drying the electrode paste and shrinking the electrode paste so that its width decreases as it moves away from the first coated surface; a lamination step of placing the first substrate on top of the second substrate from the first side with the first coated surface facing the second substrate; and a sintering step of sintering the electrode paste.

14. A method for manufacturing an electrostatic chuck member according to claim 13, comprising a second coating step performed before the drying step, wherein the second coating step is applied to the second coated surface of the second substrate, the drying step is to dry the insulating paste together with the electrode paste and shrink the insulating paste so that its width decreases as it moves away from the second coated surface, and the sintering step is a step of sintering the insulating paste together with the electrode paste.

15. A method for manufacturing an electrostatic chuck member according to claim 13, comprising: a through-hole forming step performed before the lamination step to form through holes in the second substrate; and an insertion step performed after the lamination step and before the sintering step to insert electrode terminals into the through-holes and bring them into contact with the electrode paste.

16. A method for manufacturing an electrostatic chuck member on which a plate-shaped sample is mounted on a first side in the thickness direction, comprising: an electrode forming step of cutting a plate-shaped metal material from the first surface side by etching or laser processing to form a strip-shaped heater electrode; and a lamination step of laminating a first substrate and a second substrate with the heater electrode sandwiched between them, wherein in the lamination step, the first surface is positioned facing the second side opposite to the first side in the thickness direction.

17. A method for manufacturing an electrostatic chuck member according to claim 16, comprising a groove formation step performed before the lamination step, wherein a groove is formed in the second substrate, and in the lamination step, the heater electrode is arranged inside the groove, and the width dimension of the groove increases toward the first side.

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