Heating device having electrostatic chucking function

Abstract

[Problem] To provide a heating device having an electrostatic chucking function, capable of enhancing temperature uniformity of a wafer to be heated. [Solution] A heating device 1 having an electrostatic chucking function includes at least a support base material 2, an electrostatic chucking electrode 4 and a heat generation layer 5 formed on the support base material, and an insulator layer 3 formed on the electrostatic chucking electrode and the heat generation layer. In the heating device, a hole 9 extending from an upper surface of the insulator layer on one side on which a wafer is placed to a lower surface of the insulator layer on the other side is appropriately provided, and the electrostatic chucking electrode extends from a substantially flat portion in a cross-sectional side view on the support base material along a direction toward an inside of the hole or a direction toward a lower side of an outer peripheral side surface of the heating device.

Description

Heating device with electrostatic adsorption function

[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.

[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, multi-layered heating device with electrostatic adsorption capabilities 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. Because the resistivity of the insulating layer on which the wafer is placed has low temperature dependence, this resistance-heating, multi-layered heating device with electrostatic adsorption capabilities has the advantage of being able to utilize the Johnsen-Rabek force over a wide temperature range from room temperature to 700°C, leading to its increasing use in semiconductor manufacturing processes.

[0005] JP-A-52-67353 JP-A-59-124140 JP-A-4-124076 JP-A-5-129210 JP-A-7-10665

[0006] In recent years, in high-temperature processes exceeding 200°C, there has been a demand for improved heat uniformity on the wafer mounting surface of heating equipment. The main cause of decreased heat uniformity is the presence of non-contact areas between the wafer and the wafer mounting surface, specifically the presence of non-contact areas in holes and around the outer periphery of the wafer mounting surface. When the wafer and the wafer mounting surface are not in contact, heat is dissipated from those areas, causing the wafer temperature to drop and resulting in poor heat uniformity.

[0007] Therefore, the present invention has been made in view of the above circumstances, and aims to provide a heating device having an electrostatic adsorption function that can improve the uniformity of heating of the wafer being heated.

[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, wherein the electrostatic adsorption electrode extends from a substantially flat portion in a cross-sectional side view on the support substrate in a direction toward downward 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, wherein a hole is 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, wherein the electrostatic adsorption electrode extends from a substantially flat portion in a cross-sectional side view on the support substrate in 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 x 10 １４ A heating device having electrostatic adsorption function as described in [1] or [2] above, wherein the resistivity is Ω / □ and the thickness is 50 to 500 μm. [4] When the surface resistivity in the planar direction of the insulator layer (Ω / □) is A and the volume resistivity in the thickness direction of the insulator layer (Ω・cm) 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 insulator layer is 10 ６ ~10 １５[1] to [3] above, a wafer heating apparatus having an electrostatic adsorption function, comprising a material having a value of Ω·cm. [5] A heating apparatus having an electrostatic adsorption function, comprising a material having an electrostatic adsorption electrode and / or a heating layer, comprising pyrolysis graphite containing boron and / or boron carbide in a boron concentration range of 0.001 to 30% by mass. [6] A heating apparatus having an electrostatic adsorption function, comprising a material having an electrostatic adsorption electrode and / or a heating layer, comprising a protective layer formed on the support substrate. [7] A heating apparatus having an electrostatic adsorption function, comprising a material value, comprising a material having an electrostatic adsorption function, comprising a material having an electrostatic adsorption value, comprising a material having an electrostatic adsorption function, comprising a material having an electrostatic adsorption value, comprising a material having an electrostatic adsorption function, comprising a material having an electrostatic adsorption value, comprising a material having an electrostatic adsorption value, comprising a material having an electrostatic adsorption function, comprising a material having an electrostatic adsorption value, comprising a material having a value of Ω·cm. [8] A wafer heating apparatus having electrostatic adsorption function according to any one of [1] to [7], 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 apparatus 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 apparatus having electrostatic adsorption function according to any one of [1] to [9], characterized in that the insulating layer is formed by tilting in the stacking direction using a chemical vapor deposition method.

[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.

[0011] This is a cross-sectional conceptual diagram of a heating device with electrostatic adsorption function manufactured in Example 1. This is a cross-sectional conceptual diagram of a heating device with electrostatic adsorption function manufactured in Example 2. This is a cross-sectional conceptual diagram of a heating device with electrostatic adsorption function manufactured in Example 3. This is a cross-sectional conceptual diagram of a heating device with electrostatic adsorption function manufactured in Example 4. This is a cross-sectional conceptual diagram of a heating device with electrostatic adsorption function manufactured in Example 5. This is a cross-sectional conceptual diagram of a heating device with electrostatic adsorption function manufactured in Example 6. This is a cross-sectional conceptual diagram of a heating device with electrostatic adsorption function manufactured in Comparative Example 1. This is a cross-sectional conceptual diagram of a heating device with electrostatic adsorption function manufactured in Comparative Example 2. This is a cross-sectional explanatory diagram for explaining the electrostatic adsorption electrode side portion and the adsorbed object side portion of the insulating layer.

[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 a cross-sectional side view on 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 of the insulating layers 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 a cross-sectional side view on 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 with 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 with electrostatic adsorption function, an electrostatic adsorption electrode 4 and a heating layer 5 are formed on a disc-shaped support substrate 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 heating 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 a cutout portion 7 for electrically separating the electrostatic adsorption electrode 4 and the heating layer 5 on the flat portion of the wafer placement surface due to workability during processing, resulting in a large area where the temperature decreased. In contrast, in the heating device of the present invention, the electrostatic adsorption electrode extends along the direction from the substantially flat portion in a cross-sectional side view on the support substrate toward the inside of the hole portion with an inner diameter D1 or along the direction toward the lower side of the outer peripheral side surface of the heating device. Since no cutout portion 7 is provided on the flat portion of the wafer placement surface, the area where the temperature decreases is significantly smaller than before, and the area of the electrostatic adsorption electrode can be increased, thus improving the heat uniformity (Figs. 1 to 6). In the heating device of the present invention, the electrostatic adsorption electrode is extended along the direction from the substantially flat portion in a cross-sectional side view on the support substrate toward the inside of the hole portion or along the direction toward the lower side of the outer peripheral side surface of the heating device. It is preferable to extend the electrostatic adsorption electrode in both the direction toward the inside of the hole portion and the direction toward the lower side 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 end portions of the side surface of the hole portion and the outer peripheral side surface of the heating device, and in particular, chamfered portions with a width of 0.2 to 50 mm and a length of 0.2 to 50 mm are preferably formed. Further, the electrostatic adsorption electrode extended along the direction from the substantially flat portion in a cross-sectional side view on the support substrate toward the inside of the hole portion or along the direction toward the lower side of the outer peripheral side surface of the heating device preferably exists in 5 to 100% of the chamfered portion.

[0019] Hereinafter, each configuration of the heating device 1 of the present invention will be specifically described.

[0020] <Support substrate>The material constituting the support substrate 2 is not particularly limited, but it is preferable to mainly contain any one of silicon nitride sintered bodies, boron nitride sintered bodies, mixed sintered bodies of boron nitride and aluminum nitride, alumina sintered bodies, aluminum nitride sintered bodies, pyrolytic boron nitride, and graphite such as pyrolytic boron nitride-coated graphite. These materials have stable physical properties even in the medium to high temperature range of 500 to 800°C, and in particular, graphite is desirable because it is stable up to a high temperature of 2000°C or higher.

[0021] Also, the shape of the support substrate 2 is not particularly limited, and for example, it may be disc-shaped, cylindrical, disc-shaped or cylindrical with protrusions or recesses, etc.

[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, when the support substrate 2 is an insulator, the protective layer does not necessarily have to be formed, but forming the protective layer 3 is preferable because it can prevent contamination by impurities, etc. as described above.

[0023] As the material of the protective layer 6, those that are stable up to high temperatures are preferable, and examples include silicon nitride, boron nitride, pyrolytic boron nitride, aluminum nitride, etc.

[0024] Regarding the thickness of the protective layer 6, if it is too thick, it is likely to peel off due to the difference in thermal expansion from the support substrate, and if it is too thin, there is a risk that impurities, gases, etc. will permeate through pinholes and adversely affect the subsequent manufacturing process. From the above 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] <Electrode for electrostatic adsorption and heating layer> The electrode 4 for electrostatic adsorption and the heating layer 5 are formed on the support substrate 2, and when the protective layer 3 is provided, they are formed through the protective layer 6 formed on the support substrate. As the material, it is preferably formed of pyrolytic graphite containing boron and / or boron carbide in the range of 0.001 to 30% by mass in terms of boron concentration. The electrode 4 for electrostatic adsorption and the heating layer 5 formed in this way have an anchor effect. Therefore, the insulator layer 3 formed thereon adheres and joins well, and the peeling of the insulator layer 3 can be prevented even by 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 resistivity. Therefore, using it as a heating layer has the advantage of improving temperature control. When the boron concentration is 0.001% by mass or higher, a sufficient anchoring effect is obtained, while when it is 30% by mass or lower, grain growth does not become excessive, and sufficient film formation is observed, allowing it to fully perform its function as an electrostatic adsorption electrode or 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 an electrostatic adsorption electrode and heating layer 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 obtained, and the electrical resistivity is of an appropriate size even in the medium to high temperature range of 500 to 800°C, and sufficient electrostatic adsorption force can be maintained.

[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 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 (ρsE / ρsS) is greater than 1 and 100 or less, and ρsE and ρsS are each 1 × 10⁻¹⁶ 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 part 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 portion up to 50 μm inward (towards the object to be adsorbed) from the surface of the electrostatic adsorption electrode 3, and the object to be adsorbed side portion (nearest portion) 3a-2 refers to the portion up to 50 μm inward (towards the electrostatic adsorption electrode) from the outer surface of the insulating layer 3 covering the electrostatic adsorption electrode.

[0033] Furthermore, the thickness of the insulating layer 3 covering the heating layer 5 is preferably 50 to 300 μm, and particularly preferably 80 to 200 μm.

[0034] In the present invention, the surface resistivity ρsS of the adsorbed object side portion 3a-2 is made 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 / □. It is desirable that ρsE / ρsS is greater than 1 and 100 or less, more preferably greater than 1 and 10 or less. Note that the surface resistivity of the intermediate portion 3a-3 is 2×10 ８ to 9×10 １４ Ω / □, and it is preferable to take a value intermediate between ρsE and ρsS

[0035] In the heating device of the present invention, when the temperature at the time of wafer adsorption is such that the surface resistivity (Ω / □) in the plane direction of the insulator layer is A and the volume resistivity (Ω·cm) in the thickness direction of the insulator layer is B, the ratio (A / B) of the surface resistivity to the volume resistivity is 0.01 or more. If this ratio is less than 0.01, no electrostatic adsorption force is generated, and in the worst case, dielectric breakdown may occur between the electrodes of the bipolar structure, resulting in a problem that the electrostatic adsorption function cannot be exhibited. This is considered to be because the ratio of the leakage current directly passing through the insulator layer between the electrodes of the bipolar structure increases, and the leakage current to the wafer contributing to wafer adsorption decreases, thus reducing the electrostatic adsorption force. Therefore, by setting the ratio (A / B) of the surface resistivity to the volume resistivity to 0.01 or more, preferably 0.1 or more, a practically sufficient electrostatic adsorption force is generated without causing dielectric breakdown between the bipolar electrodes, and the above problem is solved.

[0036] Also, the upper limit value 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 particularly, it is preferable to set it to 10,000 or less for the reason of ensuring the insulation withstand voltage 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 for Manufacturing a Heating Device> The method for manufacturing a 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 the electrostatic adsorption electrode 4 and the 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% by mass. A pyrolysis graphite layer containing a mixture of boron and boron carbide is formed on a support substrate 2 made of graphite having a protective layer 6 on its surface, for example. Then, this pyrolysis graphite layer is processed so that the surface 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 mass using chemical vapor deposition, minute irregularities are formed on their surfaces, resulting in a very excellent anchoring effect that effectively prevents 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 which case the electrostatic adsorption electrode 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 an 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. In other words, it provides a good temperature distribution, excellent thermal shock resistance, and prevents delamination of the insulating layer 3 even with repeated heating and cooling. Moreover, it has an appropriate resistance value and sufficient electrostatic adsorption force even in the medium to high temperature range of 500 to 800°C, and it is a heating device with an electrostatic adsorption function that can be used stably even with rapid heating and cooling without device damage due to leakage current or dielectric breakdown. Therefore, if wafers are heated using this heating device in the device manufacturing process, the yield of devices can be improved and they can be used stably over a long period of time.

[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 to 6.

[0044] (Example 1) A graphite substrate was prepared, covered with a protective layer made of pyrolysis boron nitride with a diameter of 200 mm and a thickness of 15 mm. This graphite substrate had multiple holes (inner diameter D1: 10 mm) extending from the top to the bottom, and the protective layer covered the graphite substrate, including the sides of the holes and the outer circumference of the graphite substrate. The ends of the holes were chamfered with a radius of R1.0 mm. Next, methane gas was pyrolyzed 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 in the range of 0.001 to 30% by mass, thereby forming a pyrolysis graphite layer with a thickness of 100 μm 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. In this process, a notch was made inside the hole to electrically separate the electrostatic adsorption electrode from the heating layer, and the electrode portion insulated by the notch became a non-conducting layer. At this time, the electrostatic adsorption electrode was extended into the inside of the hole to form a pattern. Subsequently, ammonia, boron trichloride, and methane were reacted on both sides of the electrostatic adsorption electrode and the heating layer under conditions of 1600°C and 5 Torr to form a 200 μm thick carbon-containing pyrolysis boron nitride insulating layer, thereby fabricating a wafer heating device with electrostatic adsorption function (Figure 1). The surface resistivity (ρsS) of the portion of the insulating layer on the side facing the adsorbed material was 2.9 × 10⁻⁶. 9 (Ω / □) and the volume resistivity in the thickness direction is 9.5 × 10⁻⁶. 9The 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. A temperature drop in the wafer was also observed in the area ± 2 mm from the center of the hole. Subsequently, the insulating layer portion of the sample described later was divided into the part immediately adjacent to the object to be adsorbed and the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part, and samples for resistivity measurement were cut out, and the surface resistivity of the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the part on the electrostatic adsorption electrode side was 1.6 × 10⁻⁶. １０ The coefficient of resistance was (Ω / □). Furthermore, the surface resistivity of the intermediate portion was 6.7 × 10⁻⁶. １０ The value was (Ω / □). Surface resistivity was measured in accordance with the JIS standard (K6911-1995 5.13 Resistivity). The measuring instrument used was a Hi-Lester IP MCP-HT260 manufactured by Dia Instruments, 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 function, in an environment of room temperature 25°C and humidity 50%.

[0045] (Example 2) As shown in Figure 2, a wafer heating device having an 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 １２ (Ω / □) and the volume resistivity in the thickness direction is 5.4 × 10⁻⁶. １１The resistance 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 from the outer edge was within 600 ± 5°C. A temperature drop in the wafer was also 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 part immediately adjacent to the object to be adsorbed and the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part, and samples for resistivity measurement were cut out, and the surface resistivity of the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the part 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 1.5 × 10⁻⁶. １３ It was (Ω / □).

[0046] (Example 3) As shown in Figure 3, a wafer heating device having an 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 side of the object to be adsorbed was 8.4 × 10 ９ (Ω / □) and the volume resistivity in the thickness direction is 6.3 × 10⁻⁶. １0 The resistance 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 away was within 600 ± 5°C. A temperature drop in the wafer was also 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 part immediately adjacent to the object to be adsorbed and the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part, and samples for resistivity measurement were cut out, and the surface resistivity of the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the part on the electrostatic adsorption electrode side was 3.5 × 10⁻⁶. １０ The coefficient of resistance was (Ω / □). Furthermore, the surface resistivity of the intermediate portion was 2.1 × 10⁻⁶. １０It 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 so as 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 upper part 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 side of 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. １０ The resistance 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. A temperature drop in the wafer was also 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 part immediately adjacent to the object to be adsorbed and the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part, and samples for resistivity measurement were cut out, and the surface resistivity of the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the electrostatic adsorption electrode side portion was 7.7 × 10⁻⁶. １３ The coefficient was (Ω / □). Furthermore, the surface resistivity of the intermediate portion 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 R-shaped portion of the outer peripheral side surface so as to electrically separate the electrostatic adsorption electrode on the outer peripheral side surface from the heating layer, and the electrostatic adsorption electrode was extended to the R-shaped portion 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 side of 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. １２The resistance 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 part immediately adjacent to the object to be adsorbed and the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part, and samples for resistivity measurement were cut out, and the surface resistivity of the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the part on the electrostatic adsorption electrode side was 2.2 × 10⁻⁶. １３ The coefficient of resistance was (Ω / □). Furthermore, the surface resistivity of the intermediate portion was 1.1 × 10⁻⁶. １３ It was (Ω / □).

[0049] (Example 6) As shown in Figure 6, a wafer heating device having an 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 side of 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 value 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 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 part immediately adjacent to the object to be adsorbed and the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part, and samples for resistivity measurement were cut out, and the surface resistivity of the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the part 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. １３It was (Ω / □).

[0050] (Comparative Example 1) As shown in Figure 7, a wafer heating device having an 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 (Ω / □) and the volume resistivity in the thickness direction is 6.6 × 10⁻⁶. １２ The 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. A temperature drop in the wafer was also 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 part immediately adjacent to the object to be adsorbed and the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part, and samples for resistivity measurement were cut out, and the surface resistivity of the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the part on the electrostatic adsorption electrode side was 5.5 × 10⁻⁶. １２ The coefficient of resistance was (Ω / □). Furthermore, the surface resistivity of the intermediate portion was 2.9 × 10⁻⁶. １２ It was (Ω / □).

[0051] (Comparative Example 2) As shown in Figure 8, a wafer heating device having an electrostatic adsorption function was manufactured in the same manner as in Example 1, except that a notch was made in the flat part of the wafer mounting surface on the outer peripheral side surface (outer peripheral side surface R3.0 mm) so as to electrically separate the electrostatic adsorption electrode on the outer peripheral side from the heating layer during pattern processing. 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. １１The 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. A temperature drop in the wafer was also 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 part immediately adjacent to the object to be adsorbed and the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part, and samples for resistivity measurement were cut out, and the surface resistivity of the part immediately adjacent to the electrostatic adsorption electrode and the intermediate part was measured. The thickness of each sample was 50 μm. The surface resistivity (ρsE) of the electrostatic adsorption electrode side portion was 1.2 × 10⁻⁶. １２ The coefficient of resistance was (Ω / □). Furthermore, the surface resistivity of the intermediate portion was 1.6 × 10⁻⁶. １１ It was (Ω / □).

[0052] (Results and Discussion) Based on the results of Examples 1 to 6 and Comparative Examples 1 to 2, the heating devices of Examples 1 to 6 were able to suppress the temperature drop of the wafer more effectively than the heating devices of Comparative Examples 1 to 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.

[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 the 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 device damage due to leakage current.

[0054] 1. Heating device with electrostatic adsorption function 2. Support base material 3. Insulator layer 3a-1. Electrostatic adsorption electrode side portion of the insulator layer covering the electrostatic adsorption electrode 3a-2. Adsorbed object side portion of the insulator layer covering the electrostatic adsorption electrode 3a-3. Middle portion of the insulator layer covering the electrostatic adsorption electrode 4. Electrostatic adsorption electrode 5. Heating layer 6. Protective layer 7. Cutout portion 8. Non-conductive layer 9. Hole portion

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, wherein the electrostatic adsorption electrode extends from a substantially flat portion of the support substrate in a cross-sectional side view along a direction toward downward 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, wherein a hole is provided extending from the upper surface of one of the insulating layers 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 cross-sectional view of the support substrate in 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. The heating device having 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. The 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 device 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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