Heating device with electrostatic adsorption function

Abstract

The present invention provides a heating device having an electrostatic adsorption function that can improve the uniformity of heating of the wafer being heated. [Solution] A heating device 1 having an electrostatic adsorption function, comprising at least a support substrate 2, an electrostatic adsorption electrode 4 and a heating layer 5 formed on the support substrate, and an insulating layer 3 formed on the electrostatic adsorption electrode and the heating layer, wherein a hole 9 is appropriately provided extending from the upper surface of one insulating layer on which a wafer is placed to the lower surface of the other insulating layer, and the electrostatic adsorption electrode extends from a substantially flat portion in a cross-sectional side view of the support substrate in a direction toward the interior of the hole, or in a direction toward the downward side of the outer peripheral surface of the heating device.

Description

[Technical Field]

[0001] The present invention relates to a heating device having an electrostatic adsorption function, and more particularly to a wafer heating device having an electrostatic adsorption function that is suitably used in a semiconductor wafer heating process in a semiconductor device manufacturing process including a temperature rise step. [Background technology]

[0002] In recent semiconductor device manufacturing processes, heating devices with electrostatic adsorption capabilities are used to electrostatically adsorb and support wafers in processes such as molecular beam epitaxy, CVD, sputtering, etching, and ion implantation. As the process temperature increases, the material of these electrostatic adsorption heating devices has shifted from resin to ceramics (see Patent Documents 1 and 2), and in high-temperature processes above 200°C, ceramic-integrated wafer heating devices that use a ceramic thin film as a heating layer are used (see, for example, Patent Document 3).

[0003] One example of a heating device with electrostatic adsorption capabilities used in such high-temperature processes is an electrostatic chuck formed from pyrolytic boron nitride and pyrolytic carbon. This device has an integrated resistance heating type with a multilayer structure and electrostatic adsorption capabilities, in which an insulating layer made of pyrolytic boron nitride (hereinafter sometimes referred to as "PBN") is formed on a (support) substrate made of carbon or a carbon composite material by thermochemical vapor deposition (thermal CVD), a conductive layer made of pyrolytic graphite formed by thermal CVD is processed into a heater pattern and bonded, and the heater pattern is further covered with a dense layered protective film such as pyrolytic boron nitride (see Patent Documents 4 and 5).

[0004] This resistance heating system, with its multilayer structure and electrostatic adsorption function, is highly pure, chemically stable, and resistant to thermal shock, making it suitable for use in various fields requiring rapid temperature changes. For example, it is widely used in semiconductor wafer manufacturing, specifically in processes where semiconductor wafers are processed one at a time, with the temperature gradually changing during processing. This heating device with an electrostatic adsorption function of a multilayer structure using a resistance heating method has the advantage that the Johnson-Lacke force can be used in a wide temperature range from room temperature to 700 °C because the temperature dependence of the resistivity of the insulator layer on which the wafer is placed is low, and its use is expanding in the semiconductor manufacturing process.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, in high-temperature processes of 200 °C or higher, an improvement in the isothermal property with respect to the wafer placement surface of the heating device has been demanded. The main cause of the deterioration of the isothermal property is the existence of non-contact portions between the wafer and the wafer placement surface, specifically, the existence of non-contact portions in the hole portions and the outer peripheral portions provided on the wafer placement surface. When the wafer and the wafer placement surface are not in contact, heat is radiated from that portion, resulting in a decrease in the temperature of the wafer and a deterioration in the isothermal property.

[0007] Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a heating device having an electrostatic adsorption function that can enhance the isothermal property of the heated wafer.

Means for Solving the Problems

[0008] To solve the above problem, the inventors investigated the cause of the temperature drop on the wafer mounting surface and found that it could be improved by extending the electrostatic chuck electrodes on the wafer mounting surface to the holes and the sides of the outer periphery. They found that the problem could be solved with the following configuration. That is, the present invention is as follows.

[0009] [1] A heating device having an electrostatic adsorption function, comprising at least a support substrate, an electrostatic adsorption electrode and a heating layer formed on the support substrate, and an insulating layer formed on the electrostatic adsorption electrode and the heating layer, A heating device having an electrostatic adsorption function, characterized in that the electrostatic adsorption electrode extends from a substantially flat portion in a cross-sectional view on the support substrate along a direction toward the downward direction toward the outer peripheral side surface of the heating device. [2] A heating device having an electrostatic adsorption function, comprising at least a support substrate, an electrostatic adsorption electrode and a heating layer formed on the support substrate, and an insulating layer formed on the electrostatic adsorption electrode and the heating layer, A hole is provided extending from the upper surface of one of the insulating layers on which the wafer is placed to the lower surface of the other insulating layer. A heating device having an electrostatic adsorption function, characterized in that the electrostatic adsorption electrode extends from a substantially flat portion in a cross-sectional side view on the support substrate along a direction toward the interior of the hole. [3] The insulating layer covering the electrostatic adsorption electrode has a ratio (ρsE / ρsS) of the surface resistivity of the electrostatic adsorption electrode side portion (ρsE) to the surface resistivity of the object to be adsorbed side portion (ρsS) which is greater than 1 and 100 or less, and ρsE and ρsS are each 1 × 10 8 The resistivity is Ω / □ or greater, and the surface resistivity of the intermediate portion of the insulating layer is 2 × 10 8 ~9×10 14 A heating device having electrostatic adsorption function as described in [1] or [2] above, wherein the ratio is Ω / □ and the thickness is 50 to 500 μm. [4] When the surface resistivity (Ω / □) of the insulating layer in the planar direction is A and the volume resistivity (Ω·cm) of the insulating layer in the thickness direction is B, the ratio of the surface resistivity to the volume resistivity (A / B) is 0.01 or more and 10,000 or less, and the volume resistivity in the thickness direction of the insulating layer is 10 6 ~10 15 A wafer heating apparatus having an electrostatic adsorption function as described in any of [1] to [3] above, comprising components having a value of Ω·cm. [5] A heating device having an electrostatic adsorption function according to any one of [1] to [4], wherein the electrostatic adsorption electrode and / or the heating layer is made of pyrolysis graphite containing boron and / or boron carbide in a boron concentration range of 0.001 to 30% by mass. [6] A heating device having an electrostatic adsorption function according to any one of [1] to [5], wherein the electrostatic adsorption electrode and / or the heating layer are formed via a protective layer formed on the support substrate. [7] A heating device having electrostatic adsorption function according to any one of [1] to [6], wherein the protective layer is made of silicon nitride, boron nitride, aluminum nitride, and pyrolysis boron nitride. [8] A wafer heating apparatus having electrostatic adsorption function according to any one of [1] to [7] above, wherein the support substrate is mainly composed of a silicon nitride sintered body, a boron nitride sintered body, a mixed sintered body of boron nitride and aluminum nitride, an alumina sintered body, an aluminum nitride sintered body, pyrolysis boron nitride, and pyrolysis boron nitride coated graphite. [9] A heating device having electrostatic adsorption function according to any one of [1] to [8], wherein the insulating layer is made of aluminum nitride, boron nitride, a mixture of aluminum nitride and boron nitride, pyrolysis boron nitride, pyrolysis boron nitride with carbon added, and pyrolysis boron nitride with carbon and silicon added.

[10] A method for manufacturing a heating device having electrostatic adsorption function according to any one of [1] to [9] above, characterized in that the insulating layer is formed by a chemical vapor deposition method with a gradient change in the stacking direction. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a heating device having an electrostatic adsorption function that can improve the uniformity of the heat distribution of the wafer on which it is placed. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional conceptual diagram of the heating device with electrostatic adsorption function manufactured in Example 1. [Figure 2] This is a cross-sectional conceptual diagram of the heating device with electrostatic adsorption function manufactured in Example 2. [Figure 3] This is a cross-sectional conceptual diagram of the heating device with electrostatic adsorption function manufactured in Example 3. [Figure 4] This is a cross-sectional conceptual diagram of the heating device with electrostatic adsorption function manufactured in Example 4. [Figure 5] This is a cross-sectional conceptual diagram of the heating device with electrostatic adsorption function manufactured in Example 5. [Figure 6] This is a cross-sectional conceptual diagram of the heating device with electrostatic adsorption function manufactured in Example 6. [Figure 7] This is a cross-sectional conceptual diagram of a heating device with electrostatic adsorption function manufactured in Comparative Example 1. [Figure 8] This is a cross-sectional conceptual diagram of a heating device with electrostatic adsorption function manufactured in Comparative Example 2. [Figure 9] This is a cross-sectional diagram illustrating the electrostatic adsorption electrode side and the adsorbed object side of the insulating layer. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described in detail below with reference to the drawings, but the present invention is not limited to these embodiments. In each drawing, the same or corresponding parts are denoted by the same reference numerals.

[0013] The present invention relates to a heating device having an electrostatic adsorption function, which is used in CVD equipment, sputtering equipment, or etching equipment for etching the resulting thin film in the manufacturing process of semiconductor devices, and has an electrostatic adsorption function for holding and fixing a semiconductor wafer, which is the object to be heated, while heating it (hereinafter sometimes simply referred to as "heating device").

[0014] The heating device of the present invention comprises at least a support substrate, an electrostatic adsorption electrode and a heating layer formed on the support substrate, and an insulating layer formed on the electrostatic adsorption electrode and the heating layer, wherein the electrostatic adsorption electrode extends from a substantially flat portion in cross-sectional view of the support substrate in a direction toward the interior of the hole, and the heating device has an extended electrostatic adsorption function. The heating device further comprises a hole extending from the upper surface of one insulating layer on which a wafer is placed to the lower surface of the other insulating layer, and the electrostatic adsorption electrode can also be extended from a substantially flat portion in cross-sectional view of the support substrate in a direction toward the interior of the hole, or toward the downward direction of the outer peripheral side surface of the heating device. Embodiments of the present invention will be described in detail below with reference to the drawings.

[0015] [Heating device with electrostatic adsorption function] Figure 1 shows an example of a heating device having an electrostatic adsorption function according to the present invention, and its configuration is shown in a partial cross-sectional side view. In this heating device 1 having an electrostatic adsorption function, an electrostatic adsorption electrode 4 and a heating layer 5 are formed on a disc-shaped support base material 2 via a protective layer 6, a notch 7 for electrically separating the electrostatic adsorption electrode 4 and the heating layer 5, and a non-conductive layer 8. Furthermore, an insulating layer 3 is formed on the electrostatic adsorption electrode 4, the heating layer 5, and the non-conductive layer 8. The non-conductive layer 8 is not electrically conductive and is adjacent to the heating layer 5 via the notch 7. Heat generated in the heating layer 5 is dispersed to the non-conductive layer 8, improving the heat dissipation efficiency of the heating device and reducing problems such as damage due to temperature rise. The electrostatic adsorption electrode 4 is formed on the wafer mounting surface side of the support substrate 2, and the heat-generating layer 5 is formed on the opposite side.

[0016] When heating a semiconductor wafer, the wafer is placed on the insulating layer 3 on the front side of the support substrate 2, fixed by electrostatic adsorption electrodes 4, and heated by the conductive heating layer 5 on the back side of the support substrate 2.

[0017] In the heating device having electrostatic adsorption function of the present invention shown in Figure 1, a hole 9 with an inner diameter D1 is formed extending from the upper surface of one of the insulating layers on which the wafer is placed to the lower surface of the other insulating layer. This hole is for a lift-up pin, a fixing screw, and gas passage.

[0018] Conventional heating devices had notches 7 installed on the flat part of the wafer mounting surface to electrically separate the electrostatic adsorption electrodes 4 and the heating layer 5 for ease of processing, resulting in a large area where the temperature dropped. In contrast, in the heating device of the present invention, the electrostatic adsorption electrode extends from a substantially flat portion of the support substrate in a cross-sectional side view toward the interior of the hole with an inner diameter D1, or toward the downward direction of the outer peripheral side surface of the heating device, and since no notches 7 are installed in the flat portion of the wafer mounting surface, the area where the temperature drops is significantly smaller than in the conventional method, and the area of ​​the electrostatic adsorption electrode can be increased, thereby improving uniform heating (Figures 1-6). In the heating device of the present invention, the electrostatic adsorption electrode extends from a substantially flat portion of the support substrate in a cross-sectional side view toward the interior of the hole, or toward the downward direction of the outer peripheral side surface of the heating device. It is preferable that the electrostatic adsorption electrode extends in both the direction toward the interior of the hole and the direction toward the downward direction of the outer peripheral side surface of the heating device. It is preferable that chamfered portions such as C-chamfers and R-chamfers are formed at the ends of the side surface of the hole and the outer peripheral side surface of the heating device, and it is particularly preferable that chamfered portions with a width of 0.2 to 50 mm and a length of 0.2 to 50 mm are formed. Furthermore, it is preferable that the electrostatic adsorption electrode, which extends from the substantially flat portion of the support substrate in a cross-sectional side view toward the interior of the hole, or toward the downward direction of the outer peripheral side surface of the heating device, is present in 5 to 100% of the chamfered portion.

[0019] The following describes in detail each component of the heating device 1 of the present invention.

[0020] <Supporting base material> The material constituting the support substrate 2 is not particularly limited, but it is preferable that it mainly consists of one of the following: silicon nitride sintered body, boron nitride sintered body, mixed sintered body of boron nitride and aluminum nitride, alumina sintered body, aluminum nitride sintered body, pyrolysis boron nitride, and graphite such as pyrolysis boron nitride coated graphite. These materials have stable physical properties even in the medium to high temperature range of 500 to 800°C, and graphite is particularly desirable because it remains stable up to high temperatures of 2000°C or higher.

[0021] Furthermore, the shape of the support base material 2 is not particularly limited and may be, for example, disc-shaped, cylindrical, or disc-shaped or cylindrical with convex or concave parts.

[0022] <Protective layer> The protective layer 6 formed on the support substrate 2 prevents impurities, gases, etc. contained in the support substrate 2 from affecting the subsequent manufacturing process. Such a protective layer 6 is essential to ensure insulation when the support substrate 2 is made of, for example, graphite, and is also necessary to prevent oxidation. On the other hand, if the support substrate 2 is an insulator, a protective layer does not necessarily have to be formed, but forming a protective layer 3 is preferable because it can prevent contamination by impurities and the like as described above.

[0023] The material of the protective layer 6 is preferably one that is stable up to high temperatures, and examples include silicon nitride, boron nitride, pyrolysis boron nitride, and aluminum nitride.

[0024] Furthermore, regarding the thickness of the protective layer 6, if it is too thick, it is prone to peeling due to the difference in thermal expansion with the supporting substrate, and if it is too thin, impurities, gases, etc. may permeate through pinholes, potentially adversely affecting the subsequent manufacturing process. From these viewpoints, the thickness of the protective layer 6 is preferably in the range of 10 to 500 μm, and particularly preferably 30 to 300 μm.

[0025] <Electrodes and heating layers for electrostatic adsorption> The electrostatic adsorption electrode 4 and the heating layer 5 are formed on the support substrate 2, and if a protective layer 3 is provided, they are formed via the protective layer 6 formed on the support substrate. Preferably, the material is pyrolysis graphite containing boron and / or boron carbide in a boron concentration range of 0.001 to 30% by mass. The electrostatic adsorption electrode 4 and heating layer 5 formed in this manner have an anchoring effect. Therefore, the insulating layer 3 formed on top of them adheres well and is bonded, preventing the insulating layer 3 from peeling off even with repeated heating and cooling.

[0026] Furthermore, pyrolysis graphite containing boron and / or boron carbide within the above range has the property of reducing the temperature dependence of its resistivity. Therefore, using it in the heating layer also has the advantage of improving temperature control. Furthermore, when the boron concentration is 0.001% by mass or higher, a sufficient anchoring effect is obtained. On the other hand, when it is 30% by mass or lower, grain growth does not become excessive, and sufficient film formation is observed, allowing the material to fully function as an electrostatic adsorption electrode or a heating layer.

[0027] The thickness of the electrostatic adsorption electrode 4 and the heating layer 5 is not particularly limited, but is preferably in the range of 10 to 500 μm, and particularly desirable to be in the range of 30 to 300 μm. With electrostatic adsorption electrodes and heating layers of this thickness, objects to be heated, such as wafers, can be suitably electrostatically adsorbed and heated.

[0028] <Insulating layer> The insulating layer 3 formed on the electrostatic adsorption electrode 4 and the heating layer 5 is 10 6 ~10 15 It is preferable that the insulating layer has a volume resistivity in the thickness direction of Ω·cm. If an insulating layer with a volume resistivity in this range is formed, the resistance value will be appropriate in the medium-high temperature range of 500°C to 800°C, preventing device damage due to leakage current and allowing sufficient electrostatic attraction force to be obtained.

[0029] Such an insulating layer 3 can preferably consist of aluminum nitride, boron nitride, a mixture of aluminum nitride and boron nitride, pyrolysis boron nitride, pyrolysis boron nitride with carbon added, and pyrolysis boron nitride with carbon and silicon added.

[0030] The thickness of the insulating layer 3 is not particularly limited, but is preferably in the range of 50 to 500 μm, and more preferably in the range of 70 to 300 μm, and even more preferably in the range of 100 to 300 μm. Generally, when an insulating layer with a thickness of 50 to 500 μm is formed, if the bonding surface of the electrostatic adsorption electrode or the heating layer is smooth, it will easily peel off due to the difference in thermal expansion coefficient. However, in the present invention, since the electrostatic adsorption electrode 4 and the heating layer 5, which have a strong anchoring effect, are formed, peeling of the insulating layer 3 can be prevented even when repeated heating and cooling is performed. Furthermore, by using an insulating layer of the above thickness, sufficient insulating force is achieved, and the electrical resistivity remains at an appropriate level even in the medium-to-high temperature range of 500 to 800°C, thus maintaining sufficient electrostatic adsorption force.

[0031] The present invention relates to a heating device having the above configuration and electrostatic adsorption function, wherein, as shown in Figure 9, the insulating layer 3 covering the electrostatic adsorption electrode 4 has a surface resistivity ρsS on the object-to-adsorbed side portion (nearest portion) 3a-2 that is smaller than the surface resistivity ρsE on the electrostatic adsorption electrode side portion (nearest portion) 3a-1. As a result, there is no residual adsorption of the wafer immediately after the applied voltage is turned off, and the non-heated material can be peeled off. Furthermore, the ratio (ρsE / ρsS) of the surface resistivity ρsE on the electrostatic adsorption electrode side portion (nearest portion) 3a-1 to the surface resistivity ρsS on the object-to-adsorbed side portion (nearest portion) 3a-2 is greater than 1 and less than or equal to 100, and ρsE and ρsS are each 1 × 10⁻⁶ 8 By setting the ratio to Ω / □ or higher, sufficient electrostatic adsorption force can be achieved from near room temperature to high temperatures. In Figure 2, 3a-3 is the intermediate portion of the insulating layer 3 covering the electrostatic adsorption electrode.

[0032] Here, the electrostatic adsorption electrode side portion (nearest portion) 3a-1 refers to the position from the surface of the electrostatic adsorption electrode 3 to 50 μm inside (in the direction of the adsorbed object), and the adsorbed object side portion (nearest portion) 3a-2 refers to the position from the outer surface of the insulator layer 3 covering the electrostatic adsorption electrode to 50 μm inside (in the direction of the electrostatic adsorption electrode).

[0033] Also, the thickness of the insulator layer 3 covering the heat generating layer 5 is preferably 50 to 300 μm, particularly preferably 80 to 200 μm.

[0034] In the present invention, the surface resistivity ρsS of the adsorbed object side portion 3a-2 is smaller than the surface resistivity ρsE of the electrostatic adsorption electrode side portion 3a-1. However, ρsE and ρsS are each 1×10 8 Ω / □ or more, preferably 1×10 8 Ω / □ to 1×10 14 Ω / □, more preferably 1×10 9 Ω / □ to 1×10 14 Ω / □, still more preferably 1×10 10 Ω / □ to 1×10 14 Ω / □, and it is desirable that they are within this range. Also, it is desirable that ρsE / ρsS is greater than 1 and 100 or less, more preferably greater than 1 and 10 or less. The surface resistivity of the intermediate portion 3a-3 can be 2×10 8 ~9×10 14 Ω / □, and it is preferable to take a value intermediate between ρsE and ρsS.

[0035] The heating device of the present invention is characterized in that, at the temperature during wafer adsorption, when the surface resistivity (Ω / □) of the insulating layer in the plane direction is A and the volume resistivity (Ω·cm) of the insulating layer in the thickness direction is B, the ratio of the surface resistivity to the volume resistivity (A / B) is 0.01 or more. If this ratio is less than 0.01, electrostatic adsorption force will not be generated, and in the worst case, dielectric breakdown may occur between the electrodes of the bipolar structure, resulting in a malfunction in which the electrostatic adsorption function is not performed. This is thought to be because the proportion of leakage current directly passing through the insulating layer between the electrodes of the bipolar structure becomes large, and the leakage current to the wafer that contributes to wafer adsorption becomes small, thus reducing the electrostatic adsorption force. Therefore, by setting the ratio of surface resistivity to volume resistivity (A / B) to 0.01 or more, preferably 0.1 or more, a practically sufficient electrostatic adsorption force is generated without dielectric breakdown occurring between the bipolar electrodes, and the above malfunction is resolved.

[0036] Furthermore, the upper limit of the ratio (A / B) of the surface resistivity to the volume resistivity is not particularly limited, but is usually 100,000 or less, and is particularly preferable to be 10,000 or less in order to ensure the dielectric strength between the electrode and the wafer.

[0037] Means for changing or adjusting the ratio (A / B) of the surface resistivity to the volume resistivity include, for example, adding and dispersing impurities in the insulating layer to create anisotropy, or annealing to give the crystalline orientation, or, when forming the insulating layer by vapor phase growth, changing the type of raw material gas, reaction temperature, reaction pressure, etc.

[0038] <Method of manufacturing a heating device> The method for manufacturing the heating device having electrostatic adsorption function according to the present invention is not particularly limited, but it can be suitably manufactured by chemical vapor deposition. For example, when forming an electrostatic adsorption electrode 4 and a heating layer 5, methane gas is reacted under conditions of 1000 to 2500°C and 1 to 10 Torr, and boron halide is introduced into the same reaction chamber at a boron concentration of 0.001 to 30 mass%. A pyrolysis graphite layer containing a mixture of boron and boron carbide is then formed on a support substrate 2 made of graphite having a protective layer 6 on its surface. Subsequently, this pyrolysis graphite layer is processed so that the front side of the support substrate 2 has the pattern of the electrostatic adsorption electrode 4, and the back side has the pattern of the heating layer 5.

[0039] Thus, by forming electrostatic adsorption electrodes 4 and / or heating layers 5 made of pyrolysis graphite containing boron and / or boron carbide in a boron concentration range of 0.001 to 30% by chemical vapor deposition, minute irregularities are formed on their surfaces, which can exhibit a very excellent anchoring effect and effectively prevent the peeling of the insulating layer 3 formed thereon.

[0040] It is preferable to form the protective layer 6 and the insulating layer 3 in the same manner by chemical vapor deposition. Each layer formed by chemical vapor deposition has high purity and suppresses peeling and particle generation. In particular, it is preferable to form the insulating layer 3 by chemical vapor deposition with a gradient change in the stacking direction. As mentioned above, the protective layer 6 is not essential depending on the support substrate 2. In this case, the electrostatic adsorption electrodes 4 and the heating layer 5 may be formed directly on the support substrate 2, and the heating device with electrostatic adsorption function can be made with the same configuration as in Figure 1.

[0041] In the present invention, the heating device having electrostatic adsorption function exhibits an anchoring effect between the electrostatic adsorption electrode 4 and the heating layer 5, preventing the insulator layer 3 formed thereon from peeling off. In particular, forming the electrostatic adsorption electrode 4 and the heating layer 5 from pyrolysis graphite containing boron and / or boron carbide in a boron concentration range of 0.001 to 30% by mass is preferable because it exhibits a stronger anchoring effect and further suppresses peeling of the insulator layer.

[0042] Furthermore, the low temperature dependence of the resistivity of the heating layer 5 results in excellent temperature control. This means that the temperature distribution is good, the thermal shock resistance is excellent, and the insulating layer 3 does not peel off even with repeated heating and cooling. Moreover, even in the medium to high temperature range of 500 to 800°C, the resistance is appropriate and sufficient electrostatic adsorption force is present. There is no device damage due to leakage current, and dielectric breakdown does not occur, resulting in a heating device with electrostatic adsorption function that can be used stably even with rapid heating and cooling. Therefore, if wafers are heated using this heating device in the device manufacturing process, the yield of devices will be improved and they can be used stably over a long period of time. [Examples]

[0043] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited thereto. Furthermore, the present invention is not limited to the embodiments described herein. These embodiments are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention. For example, the shapes of the support substrate, electrostatic adsorption electrodes, and heating layer are not limited to those shown in Figures 1-6.

[0044] (Example 1) A graphite substrate was prepared, coated with a protective layer made of pyrolysis boron nitride, with a diameter of 200 mm and a thickness of 15 mm. This graphite substrate has multiple holes (inner diameter D1: 10 mm) extending from the top to the bottom surface, and the protective layer covers the graphite substrate, including the sides of the holes and the outer circumference of the graphite substrate. The ends of the holes are chamfered with a radius of R1.0 mm. Next, methane gas was thermally decomposed on the protective layer under conditions of 2200°C and 5 Torr, and boron halide (boron trichloride) was introduced into the same reaction chamber at a boron concentration ranging from 0.001 to 30% by mass, thereby forming a 100 μm thick pyrolysis graphite layer containing a mixture of boron and boron carbide. The surface side of this pyrolysis graphite layer was processed into an electrode pattern to serve as an electrostatic adsorption electrode, and the back side was processed into a heater pattern to serve as a heating layer. At this time, notches were made inside the holes to electrically isolate the electrostatic adsorption electrodes from the heating layer, and the electrode portions insulated by the notches were made into a non-conducting layer. In this case, the electrostatic adsorption electrodes were extended into the interior of the holes to form a pattern. Subsequently, ammonia, boron trichloride, and methane were reacted on both sides of the electrostatic adsorption electrode and heating layer at 1600°C under conditions of 5 Torr to form a 200 μm thick carbon-containing pyrolysis boron nitride insulating layer, thereby fabricating a wafer heating device with electrostatic adsorption functionality (Figure 1). The surface resistivity (ρsS) of the adsorbed material side of the insulating layer was 2.9 × 10⁻⁶. 9 The coefficient is (Ω / □), and the volume resistivity in the thickness direction is 9.5 × 10⁻⁶. 9 The resistance was (Ω·cm), and the ratio (surface resistivity / volume resistivity) was 0.31. Then, with the temperature raised to 600°C, a voltage of ±500V was applied between the bipolar electrodes to adsorb the wafer. When the temperature distribution of the wafer was checked with a thermograph, the temperature drop from the outer edge of the wafer heating device to a point 2 mm away was within 600±5°C. In addition, a temperature drop of the wafer was observed in the area ±2 mm from the center of the hole. Subsequently, the insulating layer portion of the sample, as described later, was divided into the portion immediately adjacent to the object to be adsorbed and the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion. Samples for resistivity measurement were then cut out, and the surface resistivity of the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the portion on the electrostatic adsorption electrode side was 1.6 × 10⁻⁶. 10 The coefficient was (Ω / □). Furthermore, the surface resistivity of the intermediate region was 6.7 × 10⁻⁶. 10 It was (Ω / □). Surface resistivity was measured in accordance with the JIS standard (K6911-1995 5.13 Resistivity). The measuring instrument used was a Dia Instruments Hi-Lester IP MCP-HT260, and an HRS probe was used. The measurement was performed on a sample taken from near the center of a wafer heating device with electrostatic adsorption capabilities, under conditions of room temperature (25°C) and humidity (50%).

[0045] (Example 2) As shown in Figure 2, a wafer heating device with electrostatic adsorption function was manufactured in the same manner as in Example 1, except that during pattern processing, a notch was made in the R-shaped portion of the hole so as to electrically separate the electrostatic adsorption electrode in the hole from the heating layer, and the electrostatic adsorption electrode was extended to the R-shaped portion inside the hole to form the pattern. The surface resistivity (ρsS) of the portion of the insulating layer on the side of the object to be adsorbed was 9.2 × 10⁻⁶. 12 The coefficient is (Ω / □), and the volume resistivity in the thickness direction is 5.4 × 10⁻⁶. 11 The ratio was (Ω·cm), and the ratio (surface resistivity / volume resistivity) was 17.0. Then, the temperature distribution of the wafer was confirmed by thermography in the same manner as in Example 1, and the temperature drop from the outer edge of the wafer heating device to a point 2 mm away was within 600 ± 5°C. In addition, a decrease in wafer temperature was observed in the area ± 2 mm from the center of the hole. Subsequently, in the same manner as in Example 1, the insulating layer portion of the sample was divided into the portion immediately adjacent to the object to be adsorbed and the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion. Samples for resistivity measurement were then cut out, and the surface resistivity of the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the portion on the electrostatic adsorption electrode side was 3.5 × 10⁻⁶. 13 The coefficient was (Ω / □). Furthermore, the surface resistivity of the intermediate region was 1.5 × 10⁻⁶. 13 It was (Ω / □).

[0046] (Example 3) As shown in Figure 3, a wafer heating device with electrostatic adsorption function was manufactured in the same manner as in Example 1, except that, during pattern processing, a notch was made in the flat portion on the heating layer side so as to electrically separate the electrostatic adsorption electrode in the hole from the heating layer, and the electrostatic adsorption electrode was extended into the hole and extended to the notch to form the pattern. The surface resistivity (ρsS) of the portion of the insulating layer on the object to be adsorbed side was 8.4 × 10⁻⁶. 9 The coefficient is (Ω / □), and the volume resistivity in the thickness direction is 6.3 × 10⁻⁶. 10 The ratio was (Ω·cm), and the ratio (surface resistivity / volume resistivity) was 0.13. Then, the temperature distribution of the wafer was confirmed by thermography in the same manner as in Example 1, and the temperature drop from the outer edge of the wafer heating device to a point 2 mm from the outer edge was within 600 ± 5°C. In addition, a decrease in wafer temperature was observed in the area ± 2 mm from the center of the hole. Subsequently, in the same manner as in Example 1, the insulating layer portion of the sample was divided into the portion immediately adjacent to the object to be adsorbed and the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion. Samples for resistivity measurement were then cut out, and the surface resistivity of the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the portion on the electrostatic adsorption electrode side was 3.5 × 10⁻⁶. 10 The coefficient was (Ω / □). Furthermore, the surface resistivity of the intermediate region was 2.1 × 10⁻⁶. 10 It was (Ω / □).

[0047] (Example 4) As shown in Figure 4, a wafer heating device with electrostatic adsorption function was manufactured in the same manner as in Example 1, except that, during pattern processing, a notch was made in the flat part of the outer peripheral side surface to electrically separate the electrostatic adsorption electrode on the outer peripheral side from the heating layer, and the electrostatic adsorption electrode was extended to the top of the outer peripheral side surface to form a pattern (outer peripheral side surface R3.0 mm). The surface resistivity (ρsS) of the portion of the insulating layer on the object to be adsorbed was 1.1 × 10⁻⁶. 12 The coefficient is (Ω / □), and the volume resistivity in the thickness direction is 1.4 × 10⁻⁶. 10The ratio was (Ω·cm), and the ratio (surface resistivity / volume resistivity) was 78.6. Then, the temperature distribution of the wafer was confirmed by thermography in the same manner as in Example 1, and the temperature drop from the outer edge of the wafer heating device to a point 2 mm away was within 600 ± 5°C. In addition, a decrease in wafer temperature was observed in the area ± 2 mm from the center of the hole. Subsequently, in the same manner as in Example 1, the insulating layer portion of the sample was divided into the portion immediately adjacent to the object to be adsorbed and the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion. Samples for resistivity measurement were then cut out, and the surface resistivity of the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the portion on the electrostatic adsorption electrode side was 7.7 × 10⁻⁶. 13 The coefficient was (Ω / □). Furthermore, the surface resistivity of the intermediate region was 3.9 × 10⁻⁶. 13 It was (Ω / □).

[0048] (Example 5) As shown in Figure 5, a wafer heating device with electrostatic adsorption function was manufactured in the same manner as in Example 1, except that during pattern processing, a notch was made in the rounded portion of the outer peripheral side surface to electrically separate the electrostatic adsorption electrode on the outer peripheral side from the heating layer, and the electrostatic adsorption electrode was extended to the rounded portion of the outer peripheral side surface to form the pattern (outer peripheral side surface R3.0 mm). The surface resistivity (ρsS) of the portion of the insulating layer on the object to be adsorbed was 8.7 × 10⁻⁶. 11 The coefficient is (Ω / □), and the volume resistivity in the thickness direction is 7.7 × 10⁻⁶. 12 The ratio was (Ω·cm), and the ratio (surface resistivity / volume resistivity) was 0.11. Then, the temperature distribution of the wafer was confirmed by thermography in the same manner as in Example 1, and the temperature drop from the outer edge of the wafer heating device to a point 2 mm from the outer edge was within 600 ± 5°C. In addition, a decrease in wafer temperature was observed in the area ± 2 mm from the center of the hole. Subsequently, in the same manner as in Example 1, the insulating layer portion of the sample was divided into the portion immediately adjacent to the object to be adsorbed and the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion. Samples for resistivity measurement were then cut out, and the surface resistivity of the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the portion on the electrostatic adsorption electrode side was 2.2 × 10⁻⁶.13 The coefficient was (Ω / □). Furthermore, the surface resistivity of the intermediate region was 1.1 × 10⁻⁶. 13 It was (Ω / □).

[0049] (Example 6) As shown in Figure 6, a wafer heating device with electrostatic adsorption function was manufactured in the same manner as in Example 1, except that, during pattern processing, a notch was made in the flat part of the heating layer so as to electrically separate the electrostatic adsorption electrode on the outer periphery from the heating layer, and the electrostatic adsorption electrode was extended along the side of the outer periphery to the notch to form a pattern (outer periphery side radius R3.0 mm). The surface resistivity (ρsS) of the portion of the insulating layer on the object to be adsorbed was 1.0 × 10⁻⁶ 13 The coefficient is (Ω / □), and the volume resistivity in the thickness direction is 1.1 × 10⁻⁶. 10 The ratio was (Ω·cm), and the ratio (surface resistivity / volume resistivity) was 909. Then, the temperature distribution of the wafer was confirmed by thermography in the same manner as in Example 1, and the temperature drop from the outer edge of the wafer heating device to a point 2 mm away was within 600 ± 5°C. In addition, a decrease in wafer temperature was observed in the area ± 2 mm from the center of the hole. Subsequently, in the same manner as in Example 1, the insulating layer portion of the sample was divided into the portion immediately adjacent to the object to be adsorbed and the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion. Samples for resistivity measurement were then cut out, and the surface resistivity of the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the portion on the electrostatic adsorption electrode side was 3.5 × 10⁻⁶. 13 The coefficient was (Ω / □). Furthermore, the surface resistivity of the intermediate portion was 1.8 × 10⁻⁶. 13 It was (Ω / □).

[0050] (Comparative Example 1) As shown in Figure 7, a wafer heating device with electrostatic adsorption function was manufactured in the same manner as in Example 1, except that during pattern processing, a notch was made in the flat part of the wafer mounting surface so that the electrostatic adsorption electrodes on the outer periphery of the hole were electrically separated from the heating layer. The surface resistivity (ρsS) of the portion of the insulating layer on the side of the object to be adsorbed was 5.6 × 10⁻⁶. 11 The coefficient is (Ω / □), and the volume resistivity in the thickness direction is 6.6 × 10⁻⁶. 12The result was (Ω·cm), and the ratio (surface resistivity / volume resistivity) was 0.08. Then, the same test as in Example 1 was performed on the obtained heating device, and the temperature distribution of the wafer was confirmed by thermography. The temperature drop from the outer edge to 6 mm was within 600 ± 5°C. In addition, a wafer temperature drop was observed in the area ± 4 mm from the center of the hole. Subsequently, in the same manner as in Example 1, the insulating layer portion of the sample was divided into the portion immediately adjacent to the object to be adsorbed and the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion. Samples for resistivity measurement were then cut out, and the surface resistivity of the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the portion on the electrostatic adsorption electrode side was 5.5 × 10⁻⁶. 12 The coefficient was (Ω / □). Furthermore, the surface resistivity of the intermediate region was 2.9 × 10⁻⁶. 12 It was (Ω / □).

[0051] (Comparative Example 2) As shown in Figure 8, a wafer heating device with electrostatic adsorption function was manufactured in the same manner as in Example 1, except that during pattern processing, a notch was made in the flat part of the wafer mounting surface (outer peripheral side radius R3.0 mm) so as to electrically separate the electrostatic adsorption electrodes on the outer peripheral side from the heating layer. The surface resistivity (ρsS) of the portion of the insulating layer on the side of the object to be adsorbed was 3.6 × 10⁻⁶. 10 The coefficient is (Ω / □), and the volume resistivity in the thickness direction is 3.4 × 10⁻⁶. 11 The result was (Ω·cm), and the ratio (surface resistivity / volume resistivity) was 0.11. Then, the same test as in Example 1 was performed on the obtained heating device, and the temperature distribution of the wafer was confirmed by thermography. The temperature drop from the outer edge to 6 mm was within 600 ± 5°C. In addition, a wafer temperature drop was observed in the area ± 4 mm from the center of the hole. Subsequently, in the same manner as in Example 1, the insulating layer portion of the sample was divided into the portion immediately adjacent to the object to be adsorbed and the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion. Samples for resistivity measurement were then cut out, and the surface resistivity of the portion immediately adjacent to the electrostatic adsorption electrode and the intermediate portion was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the portion on the electrostatic adsorption electrode side was 1.2 × 10⁻⁶. 12The coefficient was (Ω / □). Furthermore, the surface resistivity of the intermediate region was 1.6 × 10⁻⁶. 11 It was (Ω / □).

[0052] (Results / Discussion) According to the results of Examples 1-6 and Comparative Examples 1-2, the heating devices of Examples 1-6 were able to suppress the temperature drop of the wafer more effectively than the heating devices of Comparative Examples 1-2. Based on these results, it is considered that the heating device of the present invention is effective in improving the uniformity of the heat distribution of the wafer on which it is placed. [Industrial applicability]

[0053] According to the present invention, the temperature drop at the outer edge of the wafer can be suppressed, the electrostatic adsorption electrodes are less likely to peel off inside the holes and on the outer edges, the anchoring effect of the electrostatic adsorption electrodes and the heating layer is excellent, and the boron added to the electrostatic adsorption electrodes and the heating layer chemically bonds with the nitrogen in the protective layer and insulating layer, resulting in a strong bond and eliminating the problem of peeling of the insulating layer. Furthermore, it is possible to create a heating device with an electrostatic adsorption function that has an appropriate resistance value and sufficient electrostatic adsorption force even in the medium to high temperature range of 500 to 800°C, and does not cause damage to the device due to leakage current. [Explanation of symbols]

[0054] 1. Heating device with electrostatic adsorption function 2 Supporting base material 3. Insulator layer 3a-1 Electrostatic adsorption electrode side portion of the insulating layer covering the electrostatic adsorption electrode 3a-2 Portion of the insulating layer covering the electrostatic adsorption electrode on the side facing the object to be adsorbed 3a-3 Intermediate portion of the insulating layer covering the electrostatic adsorption electrode 4. Electrodes for electrostatic adsorption 5. Heating layer 6 Protective layer 7. Cut section 8 Non-current carrying layer 9 Hole

Claims

1. A heating device having an electrostatic adsorption function, comprising at least a support substrate, an electrostatic adsorption electrode and a heating layer formed on the support substrate, and an insulating layer formed on the electrostatic adsorption electrode and the heating layer, A heating device having an electrostatic adsorption function, characterized in that the electrostatic adsorption electrode extends from a substantially flat portion in a cross-sectional view on the support substrate along a direction toward the downward direction toward the outer peripheral side surface of the heating device.

2. A heating device having an electrostatic adsorption function, comprising at least a support substrate, an electrostatic adsorption electrode and a heating layer formed on the support substrate, and an insulating layer formed on the electrostatic adsorption electrode and the heating layer, A hole is provided extending from the upper surface of one of the insulating layers on which the wafer is placed to the lower surface of the other insulating layer. A heating device having an electrostatic adsorption function, characterized in that the electrostatic adsorption electrode extends from a substantially flat portion in a cross-sectional side view on the support substrate along a direction toward the interior of the hole.

3. The insulating layer covering the electrostatic adsorption electrode has a ratio (ρsE / ρsS) of the surface resistivity of the portion on the electrostatic adsorption electrode side (ρsE) to the portion on the object to be adsorbed side (ρsS) that is greater than 1 and 100 or less, and ρsE and ρsS are each 1 × 10⁻¹⁶ ８ The resistivity is Ω / □ or greater, and the surface resistivity of the intermediate portion of the insulating layer is 2 × 10 ８ ~9 x 10 １４ A heating device having electrostatic adsorption function according to claim 1 or 2, wherein the impedance is Ω / □ and the thickness is 50 to 500 μm.

4. When the surface resistivity (Ω / □) of the insulating layer in the planar direction is A, and the volume resistivity (Ω·cm) of the insulating layer in the thickness direction is B, the ratio of the surface resistivity to the volume resistivity (A / B) is 0.01 or more and 10,000 or less, and the volume resistivity in the thickness direction of the insulating layer is 10 ６ ~10 １５ A wafer heating apparatus having an electrostatic adsorption function according to claim 1 or 2, comprising components having a value of Ω·cm.

5. A heating device having an electrostatic adsorption function according to claim 1 or 2, wherein the electrostatic adsorption electrode and / or the heating layer is made of pyrolysis graphite containing boron and / or boron carbide in a boron concentration range of 0.001 to 30% by mass.

6. A heating device having an electrostatic adsorption function according to claim 1 or 2, wherein the electrostatic adsorption electrode and / or the heating layer are formed via a protective layer formed on the support substrate.

7. The heating apparatus having electrostatic adsorption function according to claim 6, wherein the protective layer is made of silicon nitride, boron nitride, aluminum nitride, and pyrolysis boron nitride.

8. A heating device having electrostatic adsorption function according to claim 1 or 2, wherein the support substrate is mainly composed of a silicon nitride sintered body, a boron nitride sintered body, a mixed sintered body of boron nitride and aluminum nitride, an alumina sintered body, an aluminum nitride sintered body, pyrolysis boron nitride, and pyrolysis boron nitride coated graphite.

9. A heating device having electrostatic adsorption function according to claim 1 or 2, wherein the insulating layer is made of any of aluminum nitride, boron nitride, a mixture of aluminum nitride and boron nitride, pyrolysis boron nitride, pyrolysis boron nitride with carbon added, and pyrolysis boron nitride with carbon and silicon added.

10. A method for manufacturing a heating device having electrostatic adsorption function according to claim 1 or 2, characterized in that the insulating layer is formed by a chemical vapor deposition method with a gradient change in the stacking direction.

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