Power connection structure of ceramic heater or electrostatic chuck

Abstract

The present invention provides a power connection structure of a ceramic heater or an electrostatic chuck, the power connection structure comprising: a ceramic substrate; a heating wire or static electricity generating electrode, embedded in the ceramic substrate; two or more rod-shaped connectors having one end electrically connected onto a virtual circumference of the rear surface of the heating wire or the static electricity generating electrode, having the other end arranged to face the rear surface of the ceramic substrate, and embedded in the ceramic substrate; a cylindrical connection hole which is in communication with the rear surface of the ceramic substrate and exposes portions of the outer circumferential surfaces of the two or more rod-shaped connectors into the space; and a metal rod for electricity supply, which is inserted into a hollow portion of the connection hole and is electrically connected to the two or more rod-shaped connectors exposed to the connection hole.

Description

Power connection structure of ceramic heater or electrostatic chuck

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0139272 filed on October 14, 2024, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of this specification.

[0002] The present invention relates to a power connection structure for a ceramic heater or an electrostatic chuck, and more particularly to a power connection structure for a ceramic heater or an electrostatic chuck that prevents damage to the joint or breakage of the ceramic substrate due to stress concentration even when exposed to repetitive thermal loads.

[0003] A ceramic heater is a device used to heat semiconductor wafers during the semiconductor manufacturing process, and an electrostatic chuck is a device that fixes semiconductor wafers using static electricity.

[0004] Figure 1 illustrates an example of the ceramic heater. The ceramic heater (1) comprises a ceramic substrate (2), which is a circular flat plate member manufactured using a ceramic material such as aluminum nitride (AlN) or aluminum oxide (Al2O3); a hollow shaft (3) attached to the lower surface of the ceramic substrate (2); a heating wire (4) wired inside the ceramic substrate (2) to emit heat; an electrostatic generating electrode (5) wired inside the ceramic substrate (2) to generate electrostatic charge for adsorbing the semiconductor wafer; a first electric supply member (6), which is a rod member disposed in the hollow of the hollow shaft (3) and supplies electricity to the heating wire (4); a first connecting member (7) that connects the first electric supply member (6) and the heating wire (4); a second electric supply member (6'), which is a rod member disposed in the hollow of the hollow shaft (3) and supplies electricity to the electrostatic generating electrode (5); and the second electric supply member (6'). It is configured to include a second connecting member (7') that connects the electrostatic generating electrode (5) and a ring-shaped guide member (10) that fixes the electric supply members (6, 6') to a connecting hole (11) formed on the lower surface of the ceramic substrate (2).

[0005] The ceramic heater (1) of the above configuration heats the semiconductor wafer by means of the heating wire (4) and fixes the semiconductor wafer by adsorbing it using static electricity generated by the electrostatic generating electrode (5).

[0006] The conventional ceramic heater (1) has the first electric supply member (6) and the guide member (10) having a size of 13.3*10 -6 *K -1 It is manufactured from nickel (Ni) having a coefficient of thermal expansion, and the ceramic substrate (2) has a coefficient of thermal expansion of 4.4*10 -6 *K -1Aluminum nitride (AlN) or thermal expansion coefficient 8.0*10 -6 *K -1 Since it is manufactured from a ceramic material such as aluminum oxide (Al2O3; aluminum oxide), there is a large difference in the coefficient of thermal expansion between the first electric supply member (6), the guide member (10), and the ceramic substrate (2). Consequently, when a repetitive thermal load at high temperature is applied, there is a problem in that the joint between the first connecting member (7) and the first electric supply member (6) is damaged due to stress concentration, or the ceramic substrate (2) is broken.

[0007] Recently, in order to address these problems, a ceramic heater having a structure as shown in FIG. 2 has been proposed. The ceramic heater of FIG. 2 is characterized by installing a ring-shaped connector (8) at a position spaced apart from a heating wire (4) or an electrostatic generating electrode (5), and fixing an electric supply member (6') and / or an insert member (9) to a ceramic substrate by means of the ring-shaped connector (8).

[0008] The power connection structure described above provides the effect of maintaining a good connection between the electrostatic generating electrode (5) and the power supply member (6'). However, it was found that there is a problem in that thermal stress is concentrated around the insert member (9) and the ring-shaped connector (8) when frequent heating and cooling are performed in a high-temperature environment. In particular, this thermal stress has the disadvantage of causing cracks to form on the heating surface of the ceramic heater.

[0009] [Prior Art Literature]

[0010] [Patent Literature]

[0011] Korean Published Patent No. 10-2022-0169652

[0012]

[0013] The present invention has been devised to solve the above-mentioned problems of the prior art, and,

[0014] The purpose is to provide a power connection structure for a ceramic heater or electrostatic chuck that can prevent damage to the heating wire, electrostatic generating electrode, and ceramic substrate, or breakage of the joint of the power connection structure, by effectively absorbing displacement caused by the expansion or contraction of the power connection structure.

[0015]

[0016] To achieve the above objective, the present invention

[0017] Ceramic substrate;

[0018] A heating wire or electrostatic generating electrode embedded inside the ceramic substrate;

[0019] Two or more rod-shaped connectors embedded inside a ceramic substrate, with one end electrically connected on a virtual circumference on the rear surface of the heating wire or electrostatic generating electrode and the other end positioned to face the rear surface of the ceramic substrate;

[0020] A cylindrical connecting hole communicating with the rear surface of the ceramic substrate and exposing a portion of the outer surface of the two or more rod-shaped connectors into the space; and

[0021] A power connection structure for a ceramic heater or electrostatic chuck is provided, comprising: a metal rod for power supply that is inserted into the hollow portion of the above-mentioned connection hole and electrically connected to two or more rod-shaped connectors exposed through the above-mentioned connection hole.

[0022] In one embodiment of the present invention, the outer surface of two or more rod-shaped connectors exposed into the space of the cylindrical connecting hole may include a stepped portion composed of an arc-shaped wall surface having the same radius of curvature as the inner surface of the cylindrical connecting hole and a bottom surface connected to the wall surface.

[0023] In one embodiment of the present invention, an arc-shaped wall surface included on the outer surface of two or more rod-shaped connectors and exposed as a cylindrical connecting hole forms a part of the cylindrical wall surface of the connecting hole, and the bottom surface may form a part of the circular bottom surface of the connecting hole.

[0024] In one embodiment of the present invention, the metal rod for electrical supply can be electrically connected while seated on the stepped portion of the outer surface of the two or more rod-shaped connectors.

[0025] An insert member may be interposed between the above-mentioned stepped portion and the metal rod for electrical supply.

[0026] In one embodiment of the present invention, the rod-shaped connectors are composed of 2 to 10 members and may be arranged at a uniform interval from each other on a virtual circumference on the rear surface of the heating wire or electrostatic generating electrode.

[0027] In one embodiment of the present invention, the total area to which the two or more rod-shaped connectors are coupled with the rear surface of the heating wire or electrostatic generating electrode may have an area of ​​20 to 80 based on the area of ​​the front end surface of the metal rod for electric supply coupled with the rod-shaped connector.

[0028] In one embodiment of the present invention, the total area to which the two or more rod-shaped connectors are coupled with the rear surface of the heating wire or electrostatic generating electrode may have an area of ​​20 to 80% based on the area of ​​the front end surface of the insert member coupled with the rod-shaped connector.

[0029] In one embodiment of the present invention, the tip surface of the metal rod for power supply, which is electrically connected to the rear surface of the electrostatic generating electrode, may have a separation distance of 1.5 to 10 mm from the wafer placement surface of the ceramic substrate.

[0030] In one embodiment of the present invention, the front end surface of an insert member electrically connected to the rear surface of the electrostatic generating electrode may have a separation distance of 1.5 to 10 mm from the wafer placement surface of the ceramic substrate.

[0031] In one embodiment of the present invention, the two or more rod-shaped connectors may be made of a conductive ceramic material or a metal material.

[0032] In one embodiment of the present invention, the insert member may be made of a conductive ceramic material or a metal material.

[0033] In one embodiment of the present invention, the metal rod for electrical supply may include a plurality of grooves recessed inwardly on its outer surface in a direction intersecting the longitudinal direction.

[0034] In one embodiment of the present invention, the plurality of grooves are arranged spaced apart by a predetermined interval along the longitudinal direction of the metal rod, and the indentation of the plurality of grooves may be performed alternately on the left and right sides.

[0035] In one embodiment of the present invention, the power connection structure of a ceramic heater or an electrostatic chuck further comprises a guide member insertion hole formed to communicate with the connection hole, and a ring-shaped guide member coupled to the inner circumference of the guide member insertion hole.

[0036] The above-mentioned metal rod for electrical supply may be inserted into the inner surface of the ring of the above-mentioned ring-shaped guide member.

[0037]

[0038] The power connection structure of the ceramic heater or electrostatic chuck of the present invention is characterized by using a rod-shaped connector to reduce the contact area between the heating wire or electrostatic generating electrode and the metal rod (or insert member) for power supply, and to sufficiently secure the separation distance between the heating wire or electrostatic generating electrode and the metal rod (or insert member) for power supply.

[0039] Therefore, when the power connection structure expands due to heat, it effectively prevents the expansion pressure from being transmitted to the heating wire or electrostatic generating electrode and the ceramic substrate on which they are located, thereby providing the effect of preventing damage to them.

[0040] In particular, it provides a highly effective effect of preventing cracks on the heating surface, which is formed with a very thin thickness from the electrostatic generating electrode and is prone to cracking.

[0041]

[0042] FIG. 1 is a cross-sectional perspective view showing the power connection structure of a conventional ceramic heater.

[0043] Figure 2 is a cross-sectional view showing the power connection structure of a conventional ceramic heater.

[0044] FIGS. 3 and FIGS. 5 are cross-sectional views showing the electrostatic generating electrode power connection structure of the ceramic heater of the present invention.

[0045] FIGS. 4 and FIGS. 6 are cross-sectional views showing the heating wire power connection structure of the ceramic heater of the present invention.

[0046] FIG. 7 is a diagram showing the process in which a metal rod for electrical supply is inserted into a cylindrical connecting hole and coupled to a stepped portion of a rod-shaped connector in the power connection structure of the present invention.

[0047] FIG. 8 is a cross-sectional view showing the electrostatic generating electrode power connection structure and specifications of the ceramic heater of the present invention.

[0048] Figure 9 is a diagram showing the Finite Element Analysis (FEA) boundary conditions in the Von Mises stress analysis simulation of Test Example 1.

[0049] Figure 10 is a photograph showing the results of the Von Mises stress analysis of the example and comparative example in Test Example 1.

[0050] Figure 11 is a cross-sectional view showing the Finite Element Analysis (FEA) boundary conditions in the thermal stress analysis simulation of Test Example 2.

[0051] Figure 12 is a photograph showing the results of the thermal stress analysis of the example and comparative example in Test Example 2.

[0052]

[0053] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Throughout the specification, similar parts are denoted by the same reference numerals.

[0054] The present invention will be described below with reference to the drawings.

[0055] FIGS. 3 and FIGS. 4 are cross-sectional views illustrating the power connection structure of the electrostatic generating electrode and heating wire of the ceramic heater of the present invention, respectively. The power connection structure (100) of the ceramic heater or electrostatic chuck of the present invention is, as shown in FIGS. 3 and FIGS. 4,

[0056] Ceramic substrate (20);

[0057] A heating wire (35) or an electrostatic generating electrode (31) embedded inside the ceramic substrate;

[0058] Two or more rod-shaped connectors (40) embedded inside the ceramic substrate, with one end electrically connected to the virtual circumference on the rear side of the heating wire (35) or electrostatic generating electrode (31) and the other end facing the rear side of the ceramic substrate (20);

[0059] A cylindrical connecting hole (50) communicating with the rear surface of the ceramic substrate (20) and exposing a portion of the outer surface of the two or more rod-shaped connectors (40) into the space; and

[0060] It has the feature of including a metal rod (60) for electrical supply that is inserted into the above-mentioned cylindrical connecting hole (50) and electrically connected to two or more rod-shaped connectors (40) exposed through the connecting hole.

[0061] The power connection structure of the ceramic heater or electrostatic chuck described above is characterized by using a rod-shaped connector (40) to reduce the contact area between the heating wire (35) or electrostatic generating electrode (31) and the metal rod (or insert member) for power supply, and to sufficiently secure a separation distance between the heating wire or electrostatic generating electrode and the metal rod (or insert member) for power supply.

[0062] Therefore, when the power connection structure expands due to heat, it effectively prevents the expansion pressure from being transmitted to the heating wire or electrostatic generating electrode and the ceramic substrate on which they are located, thereby providing the effect of preventing damage to them. In particular, it provides the effect of very effectively preventing cracking on the heating surface (wafer placement surface), which is formed with a very thin thickness from the electrostatic generating electrode and is prone to cracking.

[0063] In one embodiment of the present invention, the outer surface of two or more rod-shaped connectors (40) exposed into the space of the cylindrical connecting hole (50) may include a stepped portion (46) composed of an arc-shaped wall surface (42) having the same radius of curvature as the inner surface of the cylindrical connecting hole (50) and a bottom surface (44) connected to the wall surface, as shown in FIG. 7.

[0064] In one embodiment of the present invention, the arc-shaped wall surface (42) included on the outer surface of the two or more rod-shaped connectors (40) and exposed as a cylindrical connecting hole forms a part of the cylindrical wall surface of the cylindrical connecting hole (50), as shown in FIG. 7, and the bottom surface (44) can form a part of the circular bottom surface of the cylindrical connecting hole (50).

[0065] In one embodiment of the present invention, the electric supply metal rod (60) can be electrically connected in a state where it is seated on a stepped portion (46) on the outer surface of two or more rod-shaped connectors (40). At this time, as shown in FIGS. 3 and 4, the outer surface of the electric supply metal rod (60) can be coupled with the arc-shaped wall surface (42) of the rod-shaped connector (40), and the front end surface of the electric supply metal rod (60) can be coupled with the bottom surface (44) of the rod-shaped connector (40). Due to this coupling structure, the coupling area between the electric supply metal rod (60) and the rod-shaped connector (40) is increased, and accordingly, a robust coupling can be formed compared to a general coupling. Therefore, the coupling structure does not separate even when high-temperature heating and cooling are repeated.

[0066] In one embodiment of the present invention, an insert member (70) may be interposed between the stepped portion (46) and the metal rod (60) for electrical supply, as shown in FIGS. 5 and 6. At this time, both the metal rod (60) for electrical supply and the insert member (70) may be fixed in a manner that forms a connection with the stepped portion (46) of the rod-shaped connector (40), as shown in FIGS. 5 and 6. However, it is not limited thereto.

[0067] In one embodiment of the present invention, the metal rod (60) for electric supply may preferably be cylindrical in shape. However, it is not limited thereto, and various polygonal column shapes may be used. The metal rod (60) for electric supply may be made of nickel (Ni), but is not limited thereto.

[0068] In one embodiment of the present invention, the two or more rod-shaped connectors (40) may be made of a conductive ceramic material or a metal material. For example, one material selected from the group consisting of molybdenum, tungsten, niobium (Nb), titanium, and rhenium, or one or more alloys selected from these may be used. Among the materials, molybdenum may be preferably used.

[0069] In one embodiment of the present invention, the insert member (70) may be made of a conductive ceramic material or a metal material. For example, one material selected from the group consisting of molybdenum, tungsten, niobium (Nb), titanium, and rhenium, or one or more alloys selected from these may be used. Among the materials, molybdenum may be preferably used.

[0070] The above insert member (70) may be in the form of a plate having a side outer surface that corresponds to the shape of the connecting hole.

[0071] In one embodiment of the present invention, the rod-shaped connectors (40) are composed of 2 to 10 members and may be arranged at a uniform interval from each other on a virtual circumference on the rear surface of the heating wire (35) or electrostatic generating electrode (31). The rod-shaped connectors (40) may be composed of 3 to 7 members, and it may be preferable to have 4 to 5 members.

[0072] The total area where the 2 to 10 rod-shaped connectors (40) are coupled to the rear surface of the heating wire (35) or electrostatic generating electrode (31) may be 20 to 80%, 20 to 70%, 20 to 50%, 20 to 40%, or 20 to 30% based on the area of ​​the front end surface of the metal rod (60) for electric supply or the front end surface of the insert member (70) coupled to the rod-shaped connector (40). In this way, if the area of ​​the rod-shaped connectors (40) coupled to the rear surface of the heating wire (35) or electrostatic generating electrode (31) is less than 20% based on the area of ​​the front end surface of the metal rod (60) for power supply or the front end surface of the insert member (70), there may be a problem in that the power applied to the electrostatic generating electrode (31) or heating wire (35) through the rod-shaped connectors (40) is weakened and good chucking force cannot be obtained, and if the area of ​​the rod-shaped connectors (40) exceeds 80%, the gap between each rod-shaped connector (40) becomes narrow, causing cracks to occur in the ceramic substrate between the rod-shaped connectors (40), or the stress concentration reduction effect of the coupling part is reduced, causing cracks to occur in the direction of the wafer placement surface of the ceramic substrate.

[0073] In one embodiment of the present invention, the front end surface of the electric supply metal rod (60) or the front end surface of the insert member (70) electrically connected to the rear surface of the electrostatic generating electrode may preferably have a spacing of 1.5 to 10 mm, preferably 1.8 to 8 mm, and more preferably 2 to 5 mm from the wafer placement surface of the ceramic substrate. When such a spacing is provided, the ceramic substrate material is positioned in the spacing portion, thereby ensuring sufficient thickness between the front end surface of the electric supply metal rod (60) or the insert member (70) and the wafer placement surface of the ceramic substrate. This allows the stress generated by the electric supply metal rod (60) or the insert member (70) to be relieved by the ceramic substrate material, thereby protecting the heating wire (35) or the electrostatic generating electrode (31), and effectively preventing cracking of the ceramic substrate heating surface (wafer placement surface) caused by the stress.

[0074] In one embodiment of the present invention, the metal rod (60) for electric supply may include a plurality of grooves (62) that are indented inwardly in a direction intersecting the longitudinal direction on the outer surface, as shown in FIG. 8.

[0075] The above-mentioned multiple grooves (62) are spaced apart by a predetermined interval along the length direction of the metal rod, and the recessing of the multiple grooves can be performed alternately on the left and right sides.

[0076] In one embodiment of the present invention, the power connection structure (100) of the ceramic heater or electrostatic chuck further comprises a guide member insertion hole (80) formed to communicate with the connection hole (50), and a ring-shaped guide member (82) coupled to the inner circumference of the guide member insertion hole, and the metal rod (60) for power supply can be inserted by penetrating the inside of the ring of the ring-shaped guide member (82).

[0077] In one embodiment of the present invention, the connection of the heating wire (35) or electrostatic generating electrode (31) with the rod-shaped connector (40), the connection of the metal rod (60) for power supply with the rod-shaped connector (40), the connection of the metal rod (60) for power supply with the insert member (70), and the connection of the insert member (70) with the rod-shaped connector (40) may be achieved by a joining method known in the art, such as brazing, and is not particularly limited.

[0078]

[0079] In one embodiment of the present invention, the ceramic substrate (20) may be manufactured using a ceramic material such as aluminum nitride (AlN; aluminum nitride), aluminum oxide (Al2O3; aluminum oxide), or aluminum oxynitride (AlON).

[0080] In one embodiment of the present invention, the cylindrical connecting hole (50) may be in a form in which several cylindrical shapes are connected as needed, as shown in FIGS. 3 to 6. That is, a guide member insertion hole (80) with a diameter larger than that of the connecting hole (50) may be formed at the rear of the connecting hole (50) to communicate with the connecting hole (50). Additionally, as shown in FIG. 3, in order to easily form the connecting hole (50) and / or the guide member insertion hole (80) and to easily perform related operations, a cylindrical hole having a diameter larger than that of the connecting hole (50) and / or the guide member insertion hole (80) may be formed at the rear end of the ceramic substrate (20) to communicate with it.

[0081] In one embodiment of the present invention, the heating wire (35) is a wire made of a conductive metal material such as molybdenum (Mo) or tungsten (W), has a circular cross-section, and can be wired in a pattern having various densities and shapes over the entire area of ​​the ceramic substrate (2). In the present invention, the heating wire (35) can be wired inside the ceramic substrate (20) in a position such that both ends are connected to the hollow interior of a hollow shaft (Fig. 1, 3).

[0082] The electrostatic generating electrode (31) may be a mesh-shaped member made of a conductive metal such as molybdenum (Mo) or tungsten (W).

[0083] In the power connection structure of the ceramic heater or electrostatic chuck of the present invention, configurations known in the art may be employed without limitation, except for the configurations described above. Therefore, a description of such configurations is omitted.

[0084]

[0085] Preferred embodiments are presented below to aid in understanding the present invention; however, the following embodiments are merely illustrative of the invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and spirit of the invention, and that such changes and modifications fall within the scope of the appended claims.

[0086]

[0087] Test Example 1: Von Mises stress analysis

[0088] The power connection structure of the ceramic heater of the present invention having the structure shown in FIG. 5 (using five rod-shaped connectors) was used as an example, and the power connection structure of a conventional ceramic heater having the structure shown in FIG. 2 was used as a comparative example to analyze the Von Mises stress occurring in the power connection part through simulation. At this time, the ceramic heaters of the example and the comparative example were manufactured identically in all other components except that the connection structure between the electrostatic generating electrode and the metal rod for power supply was configured differently.

[0089] The above Von Mises stress analysis was performed using Midas NFX simulation software, and the Finite Element Analysis (FEA) boundary conditions applied during the analysis are shown in Figure 9.

[0090] The above analysis results are shown in FIG. 10. As can be seen in FIG. 10, the power connection structure of the embodiment of the present invention shows that the von Mises stress occurring around the power connection structure is significantly reduced compared to the power connection structure of the comparative example.

[0091] Specifically, it was confirmed that the lateral stress of the connection structure was reduced by at least 20% (81 / 101.3 X 100).

[0092] In addition, it was confirmed that the stress in the direction of the electrostatic generating electrode of the connection structure was reduced by more than 52% (47.5 / 98.7 X 100).

[0093] Therefore, from these results, it can be seen that when using the power connection structure of the present invention, the occurrence of cracks in the ceramic substrate due to stress in the connection structure can be very effectively prevented. In particular, it can be seen that cracks on the heating surface, which frequently occur when using a ceramic heater, can be very effectively prevented.

[0094]

[0095] Test Example 2: Thermal Stress Analysis

[0096] The power connection structure of the ceramic heater of the present invention having the structure shown in Fig. 5 (using five rod-shaped connectors) was used as an example, and the power connection structure of a conventional ceramic heater having the structure shown in Fig. 2 was used as a comparative example to analyze the thermal stress occurring in the power connection part through simulation. At this time, the ceramic heaters of the example and the comparative example were manufactured identically in all components except that the connection structure between the electrostatic generating electrode and the metal rod for power supply was configured differently.

[0097] The above thermal stress analysis was performed using Midas NFX simulation software, and the Finite Element Analysis (FEA) boundary conditions applied during the analysis are shown in Figure 11.

[0098] The above analysis results are shown in FIG. 12. As can be seen in FIG. 12, compared to the power connection structure of the comparative example, the thermal stress generated around the power connection structure of the embodiment of the present invention is significantly reduced.

[0099] Specifically, it was confirmed that the lateral stress of the connection structure was reduced by at least 70% (5.1 / 16.5 X 100).

[0100] In addition, it was confirmed that the stress in the direction of the electrostatic generating electrode of the connection structure was reduced by at least 11% (18.7 / 21.1 X 100).

[0101] Therefore, from these results, it can be seen that when using the power connection structure of the present invention, the occurrence of cracks in the ceramic substrate due to stress in the connection structure can be very effectively prevented. In particular, it can be seen that cracks on the heating surface, which frequently occur when using a ceramic heater, can be very effectively prevented.

[0102]

[0103] Test Example 3: Durability and Power Application Test

[0104] The following test was conducted using a power connection structure of the ceramic heater of the present invention having the structure shown in FIG. 5 (including five rod-shaped connectors) as an example, and a power connection structure of a conventional ceramic heater having the structure shown in FIG. 2 as a comparative example. At this time, the ceramic heaters of the example and the comparative example were manufactured identically except that the connection structure between the electrostatic generating electrode and the metal rod for power supply was configured differently.

[0105]

[0106] (1) Durability test

[0107] Each ceramic heater was heated to 450°C under atmospheric pressure, water at 4°C was dropped onto the heated surface (wafer surface) of the ceramic substrate, and it was checked how many cycles it took for a crack to occur.

[0108] Drop conditions: Water 4℃, 4mL / spot, 30mL / min, repeat up to 50 times.

[0109] As a result of the above test, cracks were confirmed to occur in the ceramic heater of the comparative example after 5 cycles. On the other hand, no cracks occurred in the ceramic heater of the embodiment of the present invention until 50 repetitions.

[0110]

[0111] (2) RF power application test

[0112] After applying RF power, the chucking / de-chucking test, capacitance (pole to pole) test, DC leakage current test, withstand voltage test, and impedance test were performed.

[0113] As a result of the above test, the ceramic heater of the present invention showed the same or similar results as the ceramic heater of the comparative example.

[0114]

[0115] Although the present invention has been described in relation to the preferred embodiments mentioned above,

[0116] Various modifications or variations are possible without departing from the essence and scope of the invention. Accordingly, the appended claims will include such modifications or variations insofar as they fall within the essence of the invention.

[0117] [Explanation of the symbol]

[0118] 20: Ceramic substrate, 31: Heating wire

[0119] 35: Electrostatic generating electrode 40, 40a,b,c,d,e: Rod-type connector

[0120] 42: Arc-shaped wall 44: Floor surface

[0121] 46: Step section 50: Cylindrical connecting hole

[0122] 60: Metal rod for electrical supply 62: Groove

[0123] 70: Insert member 80: Guide member insertion hole

[0124] 82: Ring-shaped guide member

[0125] 100: Power connection structure of ceramic heater or electrostatic chuck

Claims

1. Ceramic substrate; A heating wire or electrostatic generating electrode embedded inside the ceramic substrate; Two or more rod-shaped connectors embedded inside a ceramic substrate, with one end electrically connected on a virtual circumference on the rear surface of the heating wire or electrostatic generating electrode and the other end positioned to face the rear surface of the ceramic substrate; A cylindrical connecting hole communicating with the rear surface of the ceramic substrate and exposing a portion of the outer surface of the two or more rod-shaped connectors into the space; and A power connection structure for a ceramic heater or electrostatic chuck comprising: a metal rod for power supply inserted into the hollow portion of the above-mentioned connection hole and electrically connected to two or more rod-shaped connectors exposed through the above-mentioned connection hole.

2. In Paragraph 1, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the outer surface of two or more rod-shaped connectors exposed into the space of the cylindrical connecting hole comprises a stepped portion consisting of an arc-shaped wall surface having the same radius of curvature as the inner surface of the cylindrical connecting hole and a bottom surface connected to said wall surface.

3. In Paragraph 2, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that an arc-shaped wall surface included on the outer surface of two or more rod-shaped connectors and exposed as a cylindrical connecting hole forms a part of the cylindrical wall surface of the connecting hole, and a bottom surface forms a part of the circular bottom surface of the connecting hole.

4. In Paragraph 2, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the above-mentioned metal rod for electric supply is electrically connected while seated on a stepped portion of the outer surface of two or more rod-shaped connectors.

5. In Paragraph 4, Power connection structure of a ceramic heater or electrostatic chuck characterized by having an insert member interposed between the above-mentioned stepped portion and a metal rod for electrical supply.

6. In Paragraph 1, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the above rod-shaped connectors consist of 2 to 10 members and are arranged at a uniform interval from each other on a virtual circumference on the rear surface of the heating wire or electrostatic generating electrode.

7. In Paragraph 1, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the total area where the two or more rod-shaped connectors are coupled to the rear surface of a heating wire or electrostatic generating electrode has an area of ​​20 to 80% based on the area of ​​the front end surface of a metal rod for power supply coupled to the rod-shaped connectors.

8. In Paragraph 5, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the total area where the two or more rod-shaped connectors are coupled to the rear surface of a heating wire or electrostatic generating electrode has an area of ​​20 to 80% based on the area of ​​the front end surface of an insert member coupled to the rod-shaped connector.

9. In Paragraph 1, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the tip surface of a metal rod for power supply, which is electrically connected to the rear surface of the electrostatic generating electrode, has a separation distance of 1.5 to 10 mm from the wafer placement surface of a ceramic substrate.

10. In Paragraph 5, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the front end surface of an insert member electrically connected to the rear surface of the electrostatic generating electrode has a separation distance of 1.5 to 10 mm from the wafer placement surface of a ceramic substrate.

11. In Paragraph 1, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the above two or more rod-shaped connectors are manufactured from a conductive ceramic material or a metal material.

12. In Paragraph 5, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the above-mentioned insert member is manufactured from a conductive ceramic material or a metal material.

13. In Paragraph 1, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the above-mentioned metal rod for electric supply includes a plurality of grooves inwardly recessed in a direction intersecting the longitudinal direction on the outer surface.

14. In Paragraph 13, A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the plurality of grooves are spaced apart by a predetermined interval along the length direction of the metal rod, and the recessing of the plurality of grooves is performed alternately left and right.

15. In Paragraph 1, A guide member insertion hole formed to communicate with the above-mentioned connecting hole, and It further includes a ring-shaped guide member coupled to the inner circumference of the guide member insertion hole, and A power connection structure for a ceramic heater or electrostatic chuck, characterized in that the above-mentioned metal rod for electric supply is inserted into the inner surface of the ring of the above-mentioned ring-shaped guide member.

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