Electrostatic chuck member and electrostatic chuck device

Abstract

This electrostatic chuck member comprises: a first substrate and a second substrate which are stacked in the thickness direction; a band-shaped heater electrode which is provided between the first substrate and the second substrate and forms a predetermined pattern; and an insulating layer which is provided, complementarily to the heater electrode, between the first substrate and the second substrate. A side surface of the heater electrode and a side surface of the insulating layer face each other with a gap therebetween. In a cross section orthogonal to the extension direction of the heater electrode, at least one among the heater electrode and the insulation layer gradually decreases in width in the thickness direction.

Description

Electrostatic chuck member and electrostatic chuck device

[0001] This application claims priority to Japanese Patent Application No. 2024-029456, filed February 29, 2024, the contents of which are incorporated herein by reference.

[0002] In a conventional semiconductor manufacturing process for manufacturing semiconductor devices such as ICs, LSIs, and VLSIs, a plate-shaped sample such as a silicon wafer is electrostatically fixed to an electrostatic chuck member having an electrostatic chuck function and then subjected to a predetermined process. In such a process, for example, after the silicon wafer is fixed by an electrostatic chuck device, the silicon wafer is subjected to a plasma etching process or a film deposition process.

[0003] In the above-described film formation process, it is known that the temperature of the plate-shaped sample during processing affects the processing results. Therefore, an electrostatic chuck device is configured to be able to heat and cool the plate-shaped sample, and is capable of controlling the temperature difference within the surface of the plate-shaped sample during processing to be small, or in other words, to prevent temperature unevenness within the surface. Hereinafter, the temperature difference within the surface of the plate-shaped sample during processing may be referred to as the "in-plane temperature difference." One such configuration is a heater electrode provided inside an electrostatic chuck member (see, for example, Patent Document 1).

[0004] JP 2012-209499 A

[0005] In the above-mentioned Patent Document 1, the heater electrode is formed by printing an electrode paste into the shape of the electrode and firing it. This method has the advantage that the heater electrode can be formed simply and at low cost.

[0006] The heater electrodes to be formed have a heater pattern in which strip-shaped electrodes are routed. An insulating layer is formed between a pair of heater electrodes adjacent to each other in the width direction of the heater electrodes in a plan view, thereby insulating the heater electrodes from each other. In an electrostatic chuck member having such heater electrodes, if it is desired to heat to a higher temperature and reduce the in-plane temperature difference, it is necessary to configure the heater electrodes to be wider in a plan view and the insulating layer to be narrower.

[0007] The inventors used an electrostatic chuck member having a heater electrode formed by the above-described method to check the temperature distribution of the surface (mounting surface) on which a plate-shaped member is placed, and found that the temperature distribution on the mounting surface sometimes varied, which differed from the simulation results based on the heater electrode design. Since the temperature variation on the mounting surface makes it difficult to control the temperature of a plate-shaped sample electrostatically attracted to the mounting surface, an improvement was required.

[0008] As a result of further investigation, the inventors found that in the electrostatic chuck member in which temperature unevenness occurred, there were locations where adjacent heater electrodes were conducting electricity and causing leakage current. In the locations where such leakage current occurred, the heater electrodes could not generate heat as designed, and it was believed that this resulted in temperature unevenness.

[0009] The inventors hypothesized that the leakage current is caused by the shape of the dried body (precursor) obtained when the electrode paste is printed and dried in the process of forming the heater electrode, and further verified this hypothesis. As a result of extensive research based on this hypothesis, the inventors have completed the present invention.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electrostatic chuck member that suppresses temperature unevenness on the mounting surface, and a further object of the present invention is to provide an electrostatic chuck device that has such an electrostatic chuck member and that enables suitable temperature control of a plate-like sample.

[0011] In order to solve the above problems, aspects of the present invention include the following electrostatic chuck member and electrostatic chuck device.

[0012] [1] An electrostatic chuck member comprising: a first substrate and a second substrate stacked in a thickness direction; a strip-shaped heater electrode provided between the first substrate and the second substrate and forming a predetermined pattern; and an insulating layer provided between the first substrate and the second substrate to be complementary to the heater electrode, wherein a side surface of the heater electrode and a side surface of the insulating layer face each other via a gap, and at least one of the heater electrode and the insulating layer has a width that gradually decreases in the thickness direction in a cross section perpendicular to an extending direction of the heater electrode.

[0013] [2] The electrostatic chuck member according to [1], wherein the heater electrode and the insulating layer have a narrower width on the first substrate side than on the second substrate side.

[0014] [3] The electrostatic chuck member described in [1], wherein the insulating layer has a narrower width on the second substrate side than on the first substrate side, and the heater electrode has a narrower width on the first substrate side than on the second substrate side.

[0015] [4] The electrostatic chuck member according to any one of [1] to [3], wherein the maximum value of the width of the gap is greater than the thickness of the insulating layer.

[0016] [5] An electrostatic chuck member according to any one of [1] to [4], wherein the width of the insulating layer gradually decreases in the thickness direction, and the amount of decrease in the width on one side of the insulating layer is greater than ¼ of the thickness of the insulating layer.

[0017] [6] The electrostatic chuck member according to any one of [1] to [5], wherein the maximum width of the heater electrode is greater than twice the maximum width of the insulating layer.

[0018] [7] An electrostatic chuck device comprising: the electrostatic chuck member according to any one of [1] to [6]; and a base that cools the electrostatic chuck member and adjusts the temperature of the electrostatic chuck member.

[0019] According to the present invention, it is possible to provide an electrostatic chuck member in which the occurrence of temperature unevenness on the mounting surface is suppressed, and it is also possible to provide an electrostatic chuck device that has such an electrostatic chuck member and enables suitable temperature control of a plate-like sample.

[0020] FIG. 1 is a cross-sectional schematic view showing an electrostatic chuck device 1 and an electrostatic chuck member 2 which are preferred examples of this embodiment. FIG. 2 is an enlarged cross-sectional view of the electrostatic chuck member 2. FIG. 3 is a process diagram showing an example of a method for manufacturing the electrostatic chuck member 2. FIG. 4 is a process diagram showing an example of a method for manufacturing the electrostatic chuck member 2. FIG. 5 is a process diagram showing an example of a method for manufacturing the electrostatic chuck member 2. FIG. 6 is a process diagram showing an example of a method for manufacturing the electrostatic chuck member 2. FIG. 7 is a schematic cross-sectional view showing an electrostatic chuck member 4 according to a modified example. FIG. 8 is an explanatory diagram of a conventional method for manufacturing an electrostatic chuck member. FIG. 9 is an explanatory diagram of a conventional method for manufacturing an electrostatic chuck member.

[0021] Hereinafter, preferred examples of an electrostatic chuck member and an electrostatic chuck device according to this embodiment will be described with reference to FIGS. 1 to 9. In all of the following drawings, the dimensions and proportions of the components have been appropriately changed to make the drawings easier to understand. The following description is provided for specific purposes to facilitate a better understanding of the spirit of the invention, and does not limit the present invention unless otherwise specified. For example, unless otherwise specified, conditions such as size, shape, position, material, amount, type, number, and ratio may be changed, added, or omitted as necessary.

[0022] 1 is a cross-sectional schematic diagram showing an electrostatic chuck device 1 and an electrostatic chuck member 2. The electrostatic chuck device 1 includes an electrostatic chuck member 2 having a mounting surface 2s on which a wafer (sample) W is mounted, a base 3 supporting the electrostatic chuck member 2 from the side opposite the mounting surface 2s, a plurality of first power supply terminals 16A, and a plurality of second power supply terminals 16B. A focus ring surrounding the wafer W may be disposed on the outer periphery of the upper surface of the electrostatic chuck member 2.

[0023] The Z axis is also shown in each drawing. In this specification, the Z axis indicates the thickness direction of a first ceramic plate 11 and a second ceramic plate 12 (the thickness direction of the electrostatic chuck member 2), which will be described later. The Z axis extends in the vertical direction, and each part of the electrostatic chuck device 1 will be described with the direction indicated by the arrow on the Z axis as the upper side and the opposite side as the lower side.

[0024] In addition, in this specification, "planar view" means viewing an object from above in the Z-axis direction.

[0025] <Electrostatic Chuck Member> The electrostatic chuck member 2 is disk-shaped. The electrostatic chuck member 2 includes a first ceramic plate 11, a second ceramic plate 12, a heater electrode 21, and an insulating layer 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 layer 22 are provided between the first ceramic plate 11 and the second ceramic plate 12.

[0026] (First Ceramic Plate) The first ceramic plate 11 has a circular plate shape in a plan view. The upper surface of the first ceramic plate 11 is a mounting surface 2s of the electrostatic chuck member 2.

[0027] An electrostatic attraction 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. For example, a plurality of protrusions (not shown) are formed at predetermined intervals on the mounting surface 2s. The mounting surface 2s supports the wafer W at the tips of the plurality of protrusions. The first opposing surface 11f faces the second ceramic plate 12.

[0028] The first ceramic plate 11 includes 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 their thickness direction aligned in the Z-axis 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.

[0029] A first bonding layer 11d and an electrostatic attraction electrode 13 are disposed between the first plate portion 11a and the second plate portion 11b. The first bonding layer 11d is provided so as to surround the electrostatic attraction electrode 13. The first bonding layer 11d bonds the first plate portion 11a and the second plate portion 11b together. The electrostatic attraction electrode 13 extends in a layered form along a plane perpendicular to the thickness direction (Z-axis direction) of the first ceramic plate 11. As a result, the electrostatic attraction electrode 13 is embedded inside the first ceramic plate 11.

[0030] A second bonding layer 11e is disposed between the second plate portion 11b and the third plate portion 11c. The second bonding layer 11e bonds the second plate portion 11b and the third plate portion 11c. A bias electrode surrounded by the second bonding layer 11e may be disposed between the second plate portion 11b and the third plate portion 11c.

[0031] The first ceramic plate 11 is formed by applying unsintered pastes constituting the electrostatic attraction electrode 13, the first bonding layer 11d, and the second bonding layer 11e between the first plate portion 11a, the second plate portion 11b, and the third plate portion 11c, which are sintered bodies formed in advance, stacking them in the thickness direction, and hot pressing them under high temperature and high pressure to integrate them.

[0032] The first ceramic plate 11 includes 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 ceramic plate 11 is made of a ceramic material. For example, aluminum oxide (Al ２ O ３ ) sintered body, aluminum nitride (AlN) sintered body, aluminum oxide (Al ２ O ３ A sintered body of silicon carbide (SiC)-based composite sintered body is preferably used. In this embodiment, 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 are made of materials having the same composition. However, 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 made of materials different from each other.

[0033] The electrostatic attraction electrode 13 is a composite of an insulating material and a conductive material. The insulating material contained in the electrostatic attraction electrode 13 is not particularly limited, but may be, 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 The conductive material is not particularly limited and can be selected arbitrarily. For example, molybdenum carbide (Mo ２ It is preferable that the material is at least one selected from the group consisting of molybdenum (Mo), tungsten carbide (WC), tungsten (W), tantalum carbide (TaC), tantalum (Ta), silicon carbide (SiC), carbon black, carbon nanotubes, and carbon nanofibers.

[0034] A first power supply terminal 16A is connected to the electrostatic attraction electrode 13. The first power supply terminal 16A applies a voltage to the electrostatic attraction electrode 13. When a voltage is applied to the electrostatic attraction electrode 13, an electrostatic attraction force is generated that holds the plate-shaped sample on the mounting surface 2s. 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 insulating insulator 18 is attached to a portion of the outer periphery of the first power supply terminal 16A. The insulator 18 insulates the first power supply terminal 16A from the base 3.

[0035] (Second Ceramic Plate) The second ceramic plate 12 has a circular plate shape in a plan view. The second ceramic plate 12 has a second opposing surface 12 f facing upward. The second opposing surface 12 f faces the first opposing surface 11 f of the first ceramic plate 11 in the up-down direction.

[0036] The second ceramic plate 12 is made of a ceramic material. Examples of the ceramic material that constitutes the second ceramic plate 12 include Al. ２ O ３ Sintered body, AlN sintered body, Al ２ O ３A -SiC composite sintered body or the like is preferably used. In this embodiment, the second ceramic plate 12 is made of the same material as the first ceramic plate 11. However, the second ceramic plate 12 may be made of a material different from that of the first ceramic plate 11. Furthermore, the second ceramic plate 12 is made of a single sintered body. However, the second ceramic plate 12 may be made by stacking and bonding multiple sintered bodies in the thickness direction. In this case, the multiple sintered bodies may be made of different ceramic materials.

[0037] (Heater Electrode, Insulating Layer) The heater electrode 21 and insulating layer 22 are located between the first ceramic plate 11 and the second ceramic plate 12. The heater electrode 21 is strip-shaped and its thickness direction coincides with that of the first ceramic plate 11 and the second ceramic plate 12, forming a predetermined pattern. The insulating layer 22 is provided in a shape complementary to the heater electrode 21. The number of insulating layers 22 and heater electrodes 21 and their shapes in a plan view can be selected arbitrarily. Note that "complementary" may mean having shapes that complement each other. For example, the side surfaces of the insulating layer 22 and the heater electrode 21 facing each other may preferably have approximately the same shape in a plan view.

[0038] A second power supply terminal 16B is connected to both longitudinal ends of the heater electrode 21. The second power supply terminal 16B passes a current through the heater electrode 21. The second power supply terminal 16B extends downward from the heater electrode 21. The second power supply terminal 16B penetrates the second ceramic plate 12 and the base 3. A cylindrical insulating insulator 18 is attached to a portion of the outer periphery of the second power supply terminal 16B. The insulator 18 insulates the second power supply terminal 16B from the base 3.

[0039] The insulating layer 22 integrally bonds the first ceramic plate 11 and the second ceramic plate 12 around the heater electrode 21. The insulating layer 22 is made of an insulating material having the same composition or the same main component as the material that forms the opposing surfaces of the first ceramic plate 11 and the second ceramic plate 12.

[0040] The heater electrode 21 and the insulating layer 22 will be described in detail later.

[0041] <Base> The base 3 is a disc-shaped member in a plan view, and supports the electrostatic chuck member 2 from below. A flow path 31 for circulating a coolant is provided inside the base 3. The coolant flowing through the flow path 31 can be selected arbitrarily, and may be, for example, water, He gas, N ２ The coolant in the flow path 31 cools the entire base 3 and also cools the electrostatic chuck member 2 in contact with the upper surface of the base 3, thereby adjusting the temperature of the electrostatic chuck member 2.

[0042] The base 3 is preferably connected to an external high frequency power source via a matching box (not shown) and also serves as an internal electrode for generating plasma.

[0043] (Other Configurations) The electrostatic chuck device 1 is 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 communication path 19c. The first gas hole 19a and the second gas hole 19b communicate with each other via the communication path 19c, and together they form the gas flow path 19.

[0044] The first gas hole 19a extends downward from the communication passage 19c and is connected to an inlet portion (not shown) for heat transfer gas at the lower end portion of the base 3. An insulator 18 is provided around the portion of the first gas hole 19a that passes through the base 3.

[0045] The second gas hole 19b extends upward from the communication passage 19c and opens to the mounting surface 2s.

[0046] The communication path 19c is located inside the electrostatic chuck member 2 and extends along the planar direction of the mounting surface 2s. In Fig. 1, the communication path 19c is provided in the second bonding layer 11e described above.

[0047] A heat transfer gas flows through the gas flow passage 19. The heat transfer gas is a cooling gas such as He. The heat transfer gas is supplied to the mounting surface 2s through the gas flow passage 19 and cools the wafer W mounted on the mounting surface 2s.

[0048] FIG. 2 is an enlarged cross-sectional view of the electrostatic chuck member 2, taken along a line perpendicular to the extending direction of the heater electrode 21. As shown in FIG.

[0049] As shown in FIG. 2, a side surface 21 a of the heater electrode 21 and a side surface 22 a of the insulating layer 22 face each other with a gap 29 therebetween.

[0050] The width of the heater electrode 21 gradually decreases in the thickness direction (Z-axis direction) from the second ceramic plate 12 toward the first ceramic plate 11. The width W11 of the heater electrode 21 on the first ceramic plate 11 (first substrate) side is narrower than the width W12 on the second ceramic plate 12 (second substrate) side.

[0051] The width of the insulating layer 22 gradually decreases in the thickness direction (Z-axis direction) from the first ceramic plate 11 toward the second ceramic plate 12. The width W22 of the insulating layer 22 on the second ceramic plate 12 side is narrower than the width W21 of the insulating layer 22 on the first ceramic plate 11 side.

[0052] The electrostatic chuck member 2 of this embodiment can solve the above problem by adopting a configuration as shown in FIG.

[0053] The inventors believe that the cause of current leakage in the heater electrode and temperature unevenness in an electrostatic chuck member in which the heater electrode is formed by printing is due to the shape of the heater electrode precursor formed in the process of forming the heater electrode.

[0054] 8 and 9 are explanatory diagrams showing a conventional method for manufacturing an electrostatic chuck member, and are explanatory diagrams for explaining a hypothesis as to the cause of leakage current.

[0055] 8 , in a conventional method for manufacturing an electrostatic chuck member, for example, a pattern of electrode paste is formed on the surface of second ceramic plate 12 and then dried to form a heater electrode precursor 511. Similarly, a pattern of insulating paste is formed on the surface of second ceramic plate 12 and then dried to form an insulating layer precursor 521. Precursor 511 and precursor 521 are spaced apart.

[0056] The precursors 511 and 521 have no noticeable difference between the upper and lower ends in cross section, and are formed into a substantially rectangular shape in cross section.

[0057] Here, the inventors believe that when the conductive paste is dried, a protruding ridge portion 51X, which is formed by segregation of solid material contained in the conductive paste, may be formed at the end of the upper surface of the precursor 511 in a cross-sectional view. When the liquid (solvent) evaporates from a liquid material (paste) containing solid matter, a ring-shaped solid matter precipitates along the outer edge of the liquid material, a phenomenon known as the "coffee ring effect."

[0058] Similarly, when the insulating paste is dried, it is believed that a protruding ridge portion 52X, which is formed by segregation of solid material contained in the insulating paste, may be formed at the end of the upper surface of the precursor 521 in a cross-sectional view.

[0059] The first ceramic plate 11 is superimposed on the second ceramic plate 12 and then fired to obtain a conventional electrostatic chuck member.

[0060] At this time, as shown in Figure 9, the convex rib portion 51X of the precursor 511 is crushed by the first ceramic plate 11, and it is thought that a transformed portion 51Y is formed in which the dried material constituting the precursor 511 spreads to the interface between the first ceramic plate 11 and the precursor 511.

[0061] Similarly, it is thought that the convex rib portion 52X of the precursor 521 is also crushed by the first ceramic plate 11, and a transformed portion 52Y is formed in which the dried material constituting the precursor 521 spreads to the interface between the first ceramic plate 11 and the precursor 521.

[0062] Furthermore, it is considered that by compressing the precursors 511 and 521 to adjust the gap between the first ceramic plate 11 and the second ceramic plate 12 (i.e., the thickness of the heater electrode and the insulating layer) to a design value, the transformation portion 51Y spreads toward the precursor 521, and the transformation portion 52Y spreads toward the precursor 511. As a result, it is considered that a mixed portion 50 is formed between the precursor 511 and the precursor 521, in which the transformation portion 51Y and the transformation portion 52Y are mixed with each other.

[0063] Furthermore, in order to heat the electrostatic chuck member to a higher temperature and reduce the in-plane temperature difference, a configuration is required in which the heater electrode is widened in plan view and the insulating layer width is narrowed. When manufacturing such an electrostatic chuck member, the mixed portions 50 generated on both sides of the precursor 521 are likely to penetrate the narrow (thin) precursor 521 from both sides in the planar direction and connect to each other. In other words, the mixed portions 50 arranged on both sides are likely to connect to each other via the transformation portion 52Y.

[0064] The mixed portion 50 contains a material of the conductive paste. Therefore, if firing is performed in a state where the mixed portion 50 is formed to form the heater electrodes 51 and the insulating layer 52, it is thought that in the area where the mixed portion 50 is formed, the heater electrodes 51 adjacent to each other with the insulating layer 52 in between will short-circuit, causing current leakage.

[0065] On the other hand, the electrostatic chuck member 2 is manufactured, for example, as follows. Figures 3 to 6 are process diagrams showing a manufacturing method of the electrostatic chuck member 2. First, as shown in Figure 3, a pattern 211 of electrode paste is formed on the surface (second opposing surface 12f) of the second ceramic plate 12 using a printing method such as screen printing. The pattern 211 has a shape corresponding to the pattern shape of the heater electrode 21 in a plan view.

[0066] The electrode paste may be made of any known material as long as it can form the heater electrode 21. The electrode paste may contain, for example, a conductive material, ceramic powder, a binder, and a solvent. The conductive material, ceramic powder, binder, and solvent may be selected arbitrarily.

[0067] Examples of conductive materials include tungsten, tungsten carbide, platinum, silver, palladium, nickel, and molybdenum.

[0068] The ceramic powder may be, for example, powder made of the same type of ceramic material as the material that constitutes the first ceramic plate 11 and the second ceramic plate 12 .

[0069] Examples of binders include ethyl cellulose, polymethyl methacrylate, and polyvinyl butyral.

[0070] The solvent may, for example, be terpineol.

[0071] 4, the pattern 211 is dried to form a precursor 212 of the heater electrode 21. The precursor 212 has a shape corresponding to the pattern shape of the heater electrode 21 in a plan view.

[0072] The width of the precursor 212 formed gradually decreases upward from the second ceramic plate 12. It may be formed into a generally trapezoidal shape in cross section. Precursor 212 of this shape may be obtained, for example, by controlling the drying conditions. For example, instead of the usual drying conditions of 30°C for 6 hours, the pattern 211 may be dried in a high-temperature environment for 30 minutes at 90°C. A protruding ridge 21X, where the solid material contained in the conductive paste segregates, is formed at the end of the upper surface of the precursor 212 in cross section. Examples of drying conditions include a higher temperature and a shorter time than usual drying conditions. Specific examples of drying temperatures include 50°C to 150°C, 150°C to 200°C, or 200°C to 250°C. The drying time may be, but is not limited to, 20 minutes to 60 minutes, 60 minutes to 120 minutes, or 120 minutes to 180 minutes. To obtain a preferred precursor, a pre-processing step for achieving preferred drying conditions may be included. For example, after forming a pattern, drying may be repeated multiple times at different temperatures and times, and these may be observed and evaluated to determine the temperature and time conditions under which a precursor with a desirable gradually decreasing width is obtained, and a precursor may be formed using these conditions.

[0073] Next, as shown in FIG. 5, a first ceramic plate 11 on which a precursor 222 of an insulating layer 22 is formed is separately prepared.

[0074] The precursor 222 is formed by forming a pattern of insulating paste on the surface (first opposing surface 11 f) of the first ceramic plate 11 using a printing method such as screen printing, and then drying the pattern, similar to the precursor 212. The precursor 222 may be formed by drying in a higher temperature environment for a shorter period of time than usual drying conditions.

[0075] The insulating paste may contain, for example, insulating ceramic powder, a binder, and a solvent.

[0076] Examples of the insulating ceramic powder include powders of the materials described above as the materials for the insulating layer 22. Examples of the binder and solvent for the insulating paste include the same materials as those used for the conductive paste described above.

[0077] It is believed that even in the precursor 222 formed in this manner, a protruding ridge portion 22X, in which the solid material contained in the conductive paste is segregated, can be formed at the end of the upper surface of the precursor 222 in a cross-sectional view.

[0078] Next, the first ceramic plate 11 and the second ceramic plate 12 are stacked together with the first opposing surface 11f and the second opposing surface 12f facing each other, and then fired to obtain the desired electrostatic chuck member.

[0079] 6 , it is believed that the protruding ridge portion 21X of the precursor 212 is crushed by the first ceramic plate 11, and a transformation portion 21Y is formed in which the dried material constituting the precursor 212 spreads to the interface between the first ceramic plate 11 and the precursor 212. The transformation portion 21Y spreads toward the interior of the precursor 212 and the gap 29 between the precursor 212 and the precursor 222. Furthermore, it is believed that the transformation portion 21Y spreads toward the precursor 222 by crushing the precursor 212 in order to adjust the gap between the first ceramic plate 11 and the second ceramic plate 12 (i.e., the thicknesses of the heater electrode 21 and the insulating layer 22) to the design value.

[0080] Similarly, it is considered that the protruding ridge portion 22X of the precursor 222 is crushed by the second ceramic plate 12, and a modified portion 22Y is formed in which the dried material constituting the precursor 222 spreads to the interface between the second ceramic plate 12 and the precursor 222. The modified portion 22Y spreads toward the interior of the precursor 222 and the gap 29. Furthermore, it is considered that the modified portion 22Y spreads toward the precursor 222 by crushing the precursor 222 to adjust the gap between the first ceramic plate 11 and the second ceramic plate 12 to the design value.

[0081] However, in the electrostatic chuck member 2, the heater electrode 21 is formed so that its width gradually decreases upward from the second ceramic plate 12. Therefore, for example, compared to when the heater electrode 21 has a rectangular shape in cross section, the transformation portion 21Y is recessed toward the precursor 212. In other words, compared to when the heater electrode 21 has a rectangular shape in cross section, the distance from the transformation portion 21Y to the precursor 222 is longer. Also, the distance from the transformation portion 22Y to the precursor 212 is longer.

[0082] In the electrostatic chuck member 2, the precursor 212 of the heater electrode 21 and the precursor 222 of the insulating layer 22 are provided on different ceramic plates. Therefore, as shown in Fig. 6, when the first ceramic plate 11 and the second ceramic plate 12 are superimposed on each other, the transformation portion 21Y is formed on the first ceramic plate 11 side, and the transformation portion 22Y is formed on the second ceramic plate 12 side. Therefore, the transformation portion 21Y and the transformation portion 22Y do not mix with each other.

[0083] As a result, in the resulting electrostatic chuck member, electrical conduction between adjacent heater electrodes is suppressed, and the occurrence of temperature unevenness on the mounting surface can be suppressed.

[0084] In the electrostatic chuck member 2 obtained in this manner, the width L of the gap 29 is preferably larger than the thickness H of the insulating layer 22. As described above, if it is considered that the transformation portion 21Y and the transformation portion 22Y are formed by crushing and deforming parts of the precursor 212 and the precursor 222, respectively, the heater electrode 21 and the insulating layer 22 can be sufficiently separated by making the width L of the gap 29 larger than the thickness H of the insulating layer.

[0085] In addition, when the width L of the gap 29 changes in the thickness direction (Z direction), it is preferable that the maximum value of the width L of the gap 29 be larger than the thickness H of the insulating layer 22 .

[0086] Furthermore, if the width reduction amount L2 on one side surface of the insulating layer 22 is sufficiently larger than the transformed portions 21Y and 22Y extending from the respective precursors, it is considered possible to prevent the transformed portions 21Y and 22Y from intermixing with each other and thus prevent the heater electrodes from becoming electrically connected to each other. Therefore, it is preferable that the width reduction amount L2 on one side surface of the insulating layer 22 be larger than ¼ times the thickness H of the insulating layer 22.

[0087] The aforementioned conduction between heater electrodes is likely to occur in conventional electrostatic chuck members, which have wide heater electrodes and narrow insulating layers in a plan view. In contrast, the electrostatic chuck member of this embodiment suppresses conduction between heater electrodes as described above, making it easier to narrow the width of the insulating layer. Therefore, in the electrostatic chuck member of this embodiment, the maximum width of the heater electrode 21 (width W12 on the second ceramic plate 12 side in FIG. 2 ) is preferably larger than the maximum width of the insulating layer 22 (width W21 on the first ceramic plate 11 side in FIG. 2 ), more preferably 1.5 times larger, and even more preferably 2 times larger. If necessary, it is also preferable for the maximum width to be 3 times or 5 times larger.

[0088] By providing each component with the above-described dimensions, leakage current between the heater electrodes can be suitably suppressed.

[0089] According to the electrostatic chuck member having the above-described configuration, it is possible to suppress the occurrence of temperature unevenness on the mounting surface.

[0090] Furthermore, according to the electrostatic chuck device having the above-described configuration, the temperature of the plate-shaped sample can be suitably controlled by having the above-described electrostatic chuck member.

[0091] 4 may be formed by laminating multiple layers of dried electrode paste patterns. In this case, the width of the multi-layered dried layers may be gradually reduced in the thickness direction to form a precursor 212 with a gradually decreasing width.

[0092] In addition, in this embodiment, the insulating layer 22 is narrower on the second ceramic plate 12 side than on the first ceramic plate 11 side, and the heater electrode 21 is narrower on the first ceramic plate 11 side than on the second ceramic plate 12 side, but this is not limiting. The reverse may also be possible as long as they are complementary to each other.

[0093] For example, the heater electrode 21 and the insulating layer 22 may be upside down, with the heater electrode 21 narrower on the second ceramic plate 12 side than on the first ceramic plate 11 side, and the insulating layer 22 narrower on the first ceramic plate 11 side than on the second ceramic plate 12 side. By placing the wider side of the heater electrode 21 on the upper side, i.e., the first ceramic plate 11 side, 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. As a result, heat from the heater electrode 21 is more easily transferred to the mounting surface 2s of the first ceramic plate 11, improving the temperature controllability of the mounting surface. Such a structure may be manufactured, for example, by modifying the manufacturing method shown in FIGS. 3 to 6 so that the precursor 212 of the heater electrode 21 is formed on the first ceramic plate 11 and the precursor 222 of the insulating layer 22 is formed on the second ceramic plate 12.

[0094] 7 , the heater electrode 21 and the insulating layer 22 may both have a width on the first ceramic plate 11 side narrower than a width on the second ceramic plate side. Specifically, the heater electrode 21 may have a width W11 on the first ceramic plate 11 side narrower than a width W12 on the second ceramic plate 12 side, and the insulating layer 22 may also have a width W21 on the first ceramic plate 11 side narrower than a width W22 on the second ceramic plate 12 side.

[0095] 7 can be manufactured by forming a precursor of the heater electrode 21 and a precursor of the insulating layer 22 on the upper surface of the second ceramic plate 12 using a printing method such as screen printing, in the same manner as in the manufacturing method of the electrostatic chuck member 2 described above, and then bonding the second ceramic plate 12 to the first ceramic plate 11. Contrary to the configuration shown in FIG. 7 , the width of both the heater electrode 21 and the insulating layer 22 on the second ceramic plate side may be narrower than the width on the first ceramic plate side.

[0096] Furthermore, at least one of the heater electrode 21 and the insulating layer 22 may have a gradually tapered width in the thickness direction. Alternatively, only the heater electrode 21 or only the insulating layer 22 may have a gradually tapered width in the thickness direction, while the other does not have a gradually tapered width.

[0097] Even in electrostatic chuck members having such a configuration, excess portions generated during the manufacturing process are recessed toward the respective precursors, so that electrical conduction between the heater electrodes can be suppressed.

[0098] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0099] DESCRIPTION OF SYMBOLS 1 Electrostatic chuck device 2, 4 Electrostatic chuck member 2s Mounting surface 3 Base 11 First ceramic plate 11a First plate portion 11b Second plate portion 11c Third plate portion 11d First bonding layer 11e Second bonding layer 11f First opposing surface 12 Second ceramic plate 12f Second opposing surface 13 Electrostatic attraction electrode 16A First power supply terminal 16B Second power supply terminal 18 Insulator 19 Gas flow path 19a First gas hole 19b Second gas hole 19c Communication path 21, 51 Heater electrode 21a, 22a Side surface 21X Convex strip portion of heater electrode precursor 21Y Transformed portion 22 Insulating layer 22X Convex strip portion of insulating layer precursor 22Y Transformed portion 29 Gap 31 Flow path 51X Convex streak portion of heater electrode precursor (substantially rectangular) 51Y Modified portion 52X Convex streak portion of insulating layer precursor (substantially rectangular) 52Y Modified portion 211 Pattern 212 Heater electrode precursor 222 Insulating layer precursor 511 Heater electrode precursor (substantially rectangular) 521 Insulating layer precursor (substantially rectangular) H Thickness L, W11, W12, W21, W22 Width L2 Reduction amount W Wafer (sample)

Claims

1. An electrostatic chuck member comprising: a first substrate and a second substrate stacked in the thickness direction; a strip-shaped heater electrode provided between the first substrate and the second substrate and forming a predetermined pattern; and an insulating layer provided between the first substrate and the second substrate in a complementary relationship to the heater electrode, wherein a side surface of the heater electrode and a side surface of the insulating layer face each other via a gap, and at least one of the heater electrode and the insulating layer has a width that gradually decreases in the thickness direction in a cross section perpendicular to the extension direction of the heater electrode.

2. The electrostatic chuck member according to claim 1, wherein the heater electrode and the insulating layer have a width on the first substrate side that is narrower than the width on the second substrate side.

3. An electrostatic chuck member according to claim 1, wherein the insulating layer has a narrower width on the second substrate side than on the first substrate side, and the heater electrode has a narrower width on the first substrate side than on the second substrate side.

4. An electrostatic chuck member according to any one of claims 1 to 3, wherein the maximum width of the gap is greater than the thickness of the insulating layer.

5. An electrostatic chuck member according to any one of claims 1 to 3, wherein the insulating layer has a width that gradually decreases in the thickness direction, and the amount of decrease in width on one side of the insulating layer is greater than 1 / 4 of the thickness of the insulating layer.

6. An electrostatic chuck member according to any one of claims 1 to 3, wherein the maximum width of the heater electrode is greater than twice the maximum width of the insulating layer.

7. An electrostatic chuck device comprising: an electrostatic chuck member according to any one of claims 1 to 3; and a base that cools the electrostatic chuck member and adjusts the temperature of the electrostatic chuck member.

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