Wafer processing equipment

Abstract

A wafer processing device according to the present invention is characterized by comprising: a processing chamber 104 which is disposed inside a vacuum container and into which a processing gas is supplied; a sample table 201 that is disposed in the processing chamber and that has a cylindrical shape for supporting a wafer to be processed; a step part that surrounds, in a ring-like manner, a placing surface which is above the sample table and on which a wafer 204 is placed; a gas dispersion plate 208 that is placed on the bottom surface of the step part and has a ring shape surrounding the placing surface; a susceptor ring 205 that is placed on the upper surface of the gas dispersion plate and that surrounds the placing surface; and recessed parts 401 that extend in the vertical direction at a plurality of positions on an inner circumferential-side wall of the susceptor ring, and that have flow paths through which an inert gas flows and which are formed by a gap between the bottom surface of the gas dispersion plate and the bottom surface of the step part, a gap between an inner circumferential-side wall of the gas dispersion plate and an outer circumferential-side wall of the step part, and a gap between the inner circumferential-side wall of the susceptor ring and the outer circumferential-side wall of the step part.

Description

Technical Field

[0001] The present invention relates to a wafer processing apparatus that processes a film layer to be processed on a substrate-like sample such as a semiconductor wafer placed on the upper surface of a sample stage disposed in a processing chamber inside a vacuum chamber. While supplying gas along the inner peripheral surface of a ring-shaped member disposed around the outer periphery of the upper surface of the sample stage toward the back surface of the outer peripheral edge of the wafer, the wafer is processed.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2017-143186 (Patent Document 1) discloses performing an atomic layer level etching process on a layer on a semiconductor wafer. Specifically, first, a step of supplying and adhering active species (radicals) of a processing gas formed using plasma to the upper surface of the semiconductor wafer as a sample to generate a product layer on the surface is performed. Thereafter, a step of irradiating the wafer with electromagnetic waves having wavelengths including infrared rays from a lamp disposed in a ring shape surrounding the region above the wafer to desorb and volatilize the product layer is performed, and the etching process is performed by removing the product layer formed to a thickness equivalent to an atomic layer.

[0003] In such a technique, for a wafer placed on a sample stage (stage) disposed in a processing chamber inside a vacuum chamber, (1) a step of forming a layer of reaction products by radicals and (2) a step of removing the reaction layer by heating irradiated with electromagnetic waves including infrared rays are performed. Regarding the reaction layer formation step of (1), first, a processing gas is supplied to a radical generation space above the processing chamber, and radicals are formed by activating the gas. The formed radical particles are supplied to the upper surface of the wafer placed in the processing chamber through a gas introduction pipe communicating between the upper processing chamber and the lower processing chamber, and a reaction layer is formed. Regarding the reaction layer removal step of (2), it is performed after (1), infrared light is irradiated from a lamp disposed above the wafer, and the product on the upper surface of the wafer is vaporized and the reaction layer is removed. These steps are alternately repeated to remove the film to be processed on the wafer surface.

[0004] On the other hand, in the etching process, reaction products are generated at various stages, and some of them adhere to or accumulate on the walls of the processing chamber. If these deposits are detached from the surface inside the processing chamber and reattach to the wafer surface, pattern defects may occur, potentially impairing the performance of semiconductor devices manufactured from that wafer. In particular, products adhering to the side walls of the stage are close to the wafer and are easily carried onto the wafer, which can easily lead to a decrease in processing yield.

[0005] Chemical or physical cleaning methods are used to address these problems. One such method is disclosed in Japanese Patent Publication No. 2022-152246 (Patent Document 2). This technique involves introducing an inert gas from the bottom of the stage and flowing it upward through the gap between the susceptor ring placed on the dispersion plate and the side wall of the stage, diffusing it into the processing chamber. The gas flow suppresses the reaction products from spreading to the side wall and back surface of the stage, while the heated gas removes any lingering foreign matter. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2017-143186 [Patent Document 2] Japanese Patent Publication No. 2022-152246 [Overview of the project] [Problems that the invention aims to solve]

[0007] In the conventional technology described above, foreign matter generation was suppressed by supplying an inert gas upward through a susceptor ring or a uniform circumferential gap between the dispersion plate and the stage, due to the supply of an inert gas upward through a susceptor ring or a uniform circumferential gap between the dispersion plate and the stage. This was achieved by adhering to the surface of the coating covering the outer peripheral side wall of the wafer mounting surface of the stage, or by interacting with the outer peripheral edge of the coating covering the surface on which the wafer is mounted and causing localized wear. Furthermore, since the dispersion plate, which is processed under high pressure, requires processing precision in the inert gas flow path, metals such as SUS are used, and in order to reduce unevenness in the supply of inert gas, the position of the gap between the plate and the stage is determined so that circumferential variation is within an acceptable range, and the position is fixed to the stage with screws or bolts.

[0008] For such metal dispersion plates, the dielectric susceptor ring, which is placed above it, is positioned by an operator to minimize circumferential variation in the gap between its inner circumference and the outer side wall of the stage. This inevitably leads to human error. Furthermore, due to differences in thermal expansion, the dielectric susceptor ring is not fixed in position relative to the dispersion plate placed below it, and as multiple wafers are processed, the circumferential variation in the gap between it and the outer side wall of the stage increases.

[0009] When the susceptor ring is eccentric and misaligned in this way, the circumferential variation in the gas flow rate supplied through the gap between the susceptor ring and the stage increases, ultimately hindering the gas supply. Furthermore, when processing at high pressure, a deposit atmosphere tends to accumulate near the stage at the bottom of the processing chamber, leading to the adhesion of particles caused by the processing gas to the stage surface, and the consumption of the adsorbed film (especially at the edges) through reaction with the plasma, resulting in the generation of foreign matter. In particular, when polyimide is used as the material for the dielectric film placed on the upper surface of the stage to electrostatically adsorb the wafer to the upper surface of the stage, it readily reacts with halogen radicals, which are often used as gas to remove (clean) the adhered deposits. In such cases, the amount of deposits and consumption on the stage surface increases, and the problem of foreign matter being generated from the stage was not considered in conventional technology, leading to problems.

[0010] As described above, in conventional technology, the eccentricity of the susceptor ring causes the edge gas flow path to become non-uniform in the circumferential direction, resulting in problems such as localized wear of the stage surface material and deterioration of uniformity within the wafer surface.

[0011] The object of the present invention is to provide a wafer processing apparatus that can improve long-term stable operation of the stage and processing efficiency even when the susceptoring is eccentric. [Means for solving the problem]

[0012] A wafer processing apparatus according to one embodiment of the present invention comprises a processing chamber disposed inside a vacuum container and supplied with a processing gas to the inside; a cylindrical sample stage disposed inside the processing chamber and supporting a wafer to be processed; a stepped portion that surrounds the mounting surface on the upper part of the sample stage in a ring shape; a ring-shaped gas dispersion plate that is placed on the bottom surface of the stepped portion and surrounds the mounting surface; a susceptor ring that is placed on the upper surface of the gas dispersion plate and surrounds the mounting surface; and a flow path through which an inert gas flows, which is formed by the gap between the bottom surface of the gas dispersion plate and the bottom surface of the stepped portion, the gap between the inner circumferential side wall of the gas dispersion plate and the outer circumferential side wall of the stepped portion, and the gap between the inner circumferential side wall of the susceptor ring and the outer circumferential side wall of the stepped portion, and is characterized in that it is provided with recesses extending in the vertical direction at multiple locations on the inner circumferential side wall of the susceptor ring. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a wafer processing apparatus that can improve the long-term stable operation of the stage and the processing efficiency. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic longitudinal cross-sectional view showing the general configuration of a wafer processing apparatus according to an embodiment of the present invention. [Figure 2] This is a schematic longitudinal cross-sectional view showing the general configuration of the stage gas supply mechanism used in the embodiment. [Figure 3] This is a schematic cross-sectional view showing the configuration of the dispersion plate in the stage gas introduction mechanism of the embodiment. [Figure 4] This diagram schematically shows the relationship between the susceptor ring and the slits in the dispersion plate that constitute the gas flow path of the stage gas introduction mechanism of Example 1. [Figure 5] This is a schematic diagram showing a modified example of the susceptor ring that constitutes the gas flow path in the stage gas introduction mechanism of Example 1, and the relationship between this and the slits in the dispersion plate. [Figure 6] This is a cross-sectional view showing the sample stage substrate that constitutes the gas flow path of the stage gas introduction mechanism of Example 2. [Figure 7]It is a cross-sectional view showing a modified example of a sample stage base material that constitutes a gas flow path included in the stage gas introduction mechanism of Example 2.

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Example

[0016] Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a longitudinal sectional view schematically showing the configuration of a wafer processing apparatus according to an embodiment of the present invention.

[0017] The wafer processing apparatus 100 according to the present embodiment shown in FIG. 1 includes a vacuum chamber 101, a discharge unit 102 that forms the upper part of the vacuum chamber 101 and forms plasma inside, and a processing chamber 104 that forms the lower part of the vacuum chamber and includes a sample stage 103 on which a semiconductor wafer (hereinafter referred to as a wafer) is placed. In other words, the sample stage 103 is a stage on which a semiconductor wafer to be processed is placed on the upper mounting surface, and is arranged inside the processing chamber 104 in the vacuum chamber 101. Further, the wafer processing apparatus 100 includes an IR lamp unit 105 that heats the wafer on the sample stage 103, and a processing chamber internal passage 1030 that includes a dielectric dispersion plate 106 that connects the discharge unit 102 and the processing chamber 104 and has a through-hole through which radical particles generated by plasma pass.

[0018] In the wafer processing apparatus 100 of the present embodiment, the processing chamber 104 and the discharge unit 102 are cylindrical spaces, and their central axes are arranged coaxially or at positions approximately approximating thereto. Between the processing chamber 104 and the discharge unit 102 disposed above it, there is a processing chamber internal passage 1030 having a cylindrical shape arranged at a position where the central axis coincides with or approximately approximates that of the processing chamber 104 and the discharge unit 102, and it is divided by a circular dispersion plate 106 disposed inside the processing chamber internal passage 1030. The discharge unit 102 and the processing chamber 104 are communicated through a plurality of through holes arranged concentrically on the dispersion plate 106, and the gas supplied into the discharge unit 102 is excited as described later and flows through the processing chamber internal passage 1030 toward the lower processing chamber 104 and is supplied into the processing chamber 104 through the through holes of the dispersion plate 106.

[0019] The discharge unit 102 is configured such that the processing gas 1013 flows in, forms plasma 1011, and the plasma state can be observed by an optical method. Thus, a processing gas supply path, which is a supply path including the discharge unit 102 and supplies the processing gas 1013 for processing the wafer into the processing chamber 104, is disposed above the sample stage 103.

[0020] The discharge unit 102 includes a cylindrical quartz chamber (dielectric chamber) 107 that forms the upper part of the vacuum vessel 101 and whose interior is communicated with the processing chamber 104 and depressurized, and an ICP coil 108 disposed outside the outer peripheral side wall surface of the quartz chamber 107 with a gap opened on the side wall surface and wound around it a plurality of times. A high-frequency power source for plasma generation is connected to the ICP coil 108 via a matcher, and plasma 1011 is generated in the quartz chamber 107 by an ICP (Inductively Coupled Plasma) discharge method using the high-frequency power supplied from the high-frequency power source. The frequency of the high-frequency power is assumed to use a frequency band of several tens of MHz such as 13.56 MHz.

[0021] A top plate 1014 is installed above the discharge section 102. A dispersion plate 106 and a shower plate are installed below the discharge section 102, and the processing gas 1013 is introduced into the vacuum chamber 101 via the dispersion plate 106 and the shower plate. As described above, the supply flow rate of the introduced processing gas 1013 is adjusted by a mass flow controller installed for each type of gas. As the processing gas 1013, flammable gas, combustion-supporting gas, and mixtures thereof, or mixtures thereof diluted with an inert gas are used. The top plate 1014 is placed on the quartz chamber 107 and attached to the discharge section 102 with a sealing member such as an O-ring sandwiched between the back surface of its outer peripheral edge and the upper surface of the upper end of the quartz chamber 107. This hermetically seals the inside of the discharge section 102 and the outside of the vacuum chamber 101.

[0022] An exhaust opening is provided at the bottom of the processing chamber 104 to reduce the pressure inside the vacuum vessel 101, and the vacuum vessel 101 is connected to a vacuum pump through an exhaust pipe from this opening. A pressure regulating valve is placed in the path between the opening and the vacuum pump to adjust the flow rate or speed of the exhaust 1017 by increasing or decreasing the cross-sectional area of ​​the path or opening.

[0023] The processing chamber 104 has a sample stage 103 on which the wafer 204 is placed, positioned at a location that coincides with or approximates to the central axis of the discharge section 102 and the processing chamber 104.

[0024] The IR lamp unit 105 for heating the wafer 204 is positioned above the processing chamber 104 and above the outer periphery of the sample stage 103. It is also positioned to surround the outer periphery of the passage 1030 within the processing chamber. In the center of the IR lamp unit 105, there is a channel that serves as a passage for radicals, and a dielectric dispersion plate 106 with multiple concentric through-holes (passages) is installed in this channel to shield ions and electrons generated by the plasma and allow neutral particles or radical particles of the gas to pass through. The IR lamp unit 105 mainly consists of an IR lamp 1020, a reflector 1021 for reflecting IR light, and a light-transmitting window 1022 that transmits IR light. The IR lamp 1020 for wafer heating is installed in an atmospheric environment, and the light-transmitting window 1022, which separates the reduced-pressure atmosphere inside the processing chamber 104 from the atmospheric atmosphere, is installed from the bottom surface of the IR lamp unit 105 to the outer wall surface of the passage 1030 within the processing chamber.

[0025] A circular IR lamp 1020 is used. Specifically, the IR lamp 1020, which heats the wafer 204 by irradiating it with electromagnetic waves, is arranged in a ring shape above the sample stage 103 and around the processing gas supply path. The light emitted from the IR lamp 1020 mainly consists of light in the visible to infrared region (referred to here as IR light). The IR lamp 1020 is connected to a lamp power supply that provides power. In this embodiment, the near-infrared region from 500 nm to 3000 nm is used for wafer temperature control, and the far-infrared region from 3000 nm onward is used for IR absorption of the cleaning gas. With this configuration, not only the wafer 204 but also the dispersion plate 106 can be heated by the IR lamp 1020 for wafer heating. As a result, the ion shielding slit plate is also heated by the light for wafer heating, reducing the amount of radicals adhering to the deposited film on the slit plate and suppressing the generation of foreign particles caused by the formation of the deposited film.

[0026] Although not shown in the diagram, the power supplied to each arc-shaped portion of the IR lamps 1020 (three in the diagram) located at each radius on a concentric circle can be adjusted independently, allowing for adjustment of the radial distribution of heating of the wafer 204.

[0027] In the wafer processing apparatus 100 of this embodiment, the following steps are performed on the wafer 204. Specifically, first, (1) a step of forming a reaction product layer by radicals on the surface of the wafer 204, and (2) a step of irradiating the surface of the wafer 204 with electromagnetic waves including infrared rays to heat the surface of the wafer 204 and remove the reaction product layer.

[0028] In the step of generating the reaction product layer in (1), first, a processing gas 1013 is supplied into the discharge unit 102 and activated to generate plasma 1011. The formed plasma 1011 is shielded from ions and electrons by the dispersion plate 106, and only radical particles or neutral particles are supplied to the lower processing chamber 104 and supplied to the upper surface of the wafer 204 placed in the lower processing chamber 104, thereby forming the reaction product layer. In other words, radical particles or neutral particles of the processing gas 1013 are introduced onto the wafer 204 placed on the mounting surface of the sample stage 103, and a reaction product layer is formed on the surface of the film to be processed that is pre-formed on the upper surface of the wafer 204. In the step of removing the reaction product layer in (2), the process is carried out after the step in (1), and infrared light (electromagnetic waves) is irradiated from the IR lamp unit 105 placed on the upper part of the wafer 204, and the product on the upper surface of the wafer 204 is vaporized, thereby removing the reaction product layer. These steps are repeated alternately until the film to be processed on the surface of the wafer 204 is removed.

[0029] Figure 2 is a schematic longitudinal cross-sectional view showing the configuration of the stage gas supply mechanism of this embodiment shown in Figure 1. The sample stage 103 shown in this figure has a cylindrical structure coaxial with the central axis of the processing chamber 104, and has an internal sample stage base material 201 and an upper surface sample adsorption film 202. The sample stage base material 201 also has a ring-shaped stepped portion surrounding the outer periphery of the upper surface of the sample adsorption film 202. A gas dispersion plate 208 is placed on the bottom surface of the ring-shaped stepped portion, and a susceptor ring 205 is placed on the upper surface of the gas dispersion plate 208.

[0030] The sample stage base material 201 has a refrigerant channel 216 formed inside for cooling the sample stage 103, and the refrigerant is circulated and supplied by a chiller 215. In addition, plate-shaped electrode plates (electrodes for electrostatic adsorption) 203 are embedded in the stage to fix the wafer 204 by electrostatic adsorption, and a DC power supply (power supply for electrostatic adsorption) is connected to each. Furthermore, in order to efficiently cool the wafer 204, He gas can be supplied between the back surface of the wafer 204 and the sample stage 103. In other words, the wafer 204 is equipped with both fixation adsorption and cooling functions.

[0031] A resin sheet, such as polyimide, is attached to the sample adsorption film 202 to prevent damage to the back surface of the wafer 204 even when heating and cooling cycles are performed while the wafer 204 is adsorbed. In addition, a plate-shaped electrode plate 203 is embedded in the sample adsorption film 202 to fix the wafer 204 by electrostatic adsorption, and the electrode plate 203 is connected to a DC power supply. A groove is also provided in the sample adsorption film 202, which serves as a path for supplying He gas between the wafer 204 and the sample adsorption film 202. As a result, the sample stage 103, whose temperature is controlled by the refrigerant path, and the wafer 204 can come into thermal contact through the He gas, and the wafer 204 heated by the IR lamp unit 105 is efficiently cooled.

[0032] A quartz susceptor ring 205 is placed around the outer periphery of the sample stage 103 to protect it from corrosion by etching gas. The susceptor ring 205 is cylindrical with the same central axis as the sample stage, and its inner diameter is designed to match the diameters of the side walls of the sample stage base material 201 and the sample adsorption film 202, covering the sample stage 103 except for the area on which the wafer 204 is placed. The susceptor ring 205 is made of a translucent material (e.g., quartz). In other words, the dielectric susceptor ring 205 is placed on the sample stage 103, surrounding the periphery of the mounting surface of the sample stage 103.

[0033] A gas dispersion plate 208 is positioned on the upper surface of a ring-shaped stepped portion surrounding the outer periphery of the sample adsorption film 202 surface on the upper part of the sample stage base material 201, and a susceptor ring 205 is placed on its upper surface. The susceptor ring 205 is cylindrical with the same central axis as the sample stage, and its inner diameter is designed to match the diameters of the convex-shaped outer periphery side wall 209 of the stage created by the ring-shaped stepped portion of the sample stage base material 201 and the side walls of the sample adsorption film 202, covering the area from the upper surface of the gas dispersion plate 208 to the outer periphery side wall surface of the sample stage base material 201. The upper surface of the susceptor ring 205 is designed to be lower than the mounting surface of the sample stage 103 (the upper surface of the sample adsorption film 202), so that the lower surface of the wafer 204 and the upper surface of the susceptor ring 205 do not come into contact. The susceptor ring 205 is made of a translucent material (e.g., quartz). In other words, the dielectric susceptor ring 205 is positioned on the sample stage 103, surrounding the periphery of the mounting surface of the sample stage 103.

[0034] Below the susceptor ring 205 is a stage gas introduction mechanism 206 for removing foreign matter accumulated on the side of the sample stage 103 and for suppressing the entry of foreign matter. The stage gas introduction mechanism 206 is a mechanism having internal stage piping 207 and a gas dispersion plate 208. The gas supplied from the internal stage piping 207 is a non-volatile gas such as Ar (argon), or a molecular gas containing CH, OH, NH, C=O, C=C, or CO bonds (referred to here as an IR absorbing gas). Ar gas is used to suppress the entry of reaction products into the side of the stage during the process. IR absorbing gases can be used for heating and removing foreign matter because the stretching and bending vibrations of the molecules resonate with the wavelength of IR light and efficiently absorb energy.

[0035] The IR light emitted from the IR lamp unit 105 has wavelengths in the wavelength range absorbed by the gas. For example, if the gas is carbon dioxide, it is desirable that the IR light be in the far-infrared region. Specifically, the wavelength of the IR light is preferably 10.1 to 14.9 μm or 3.2 to 3.7 μm if the gas bond is CH, 2.7 to 3.1 μm if OH, and 2.9 μm if NH. Furthermore, the wavelength of the IR light is preferably 5.5 to 6.5 μm if the gas bond is C=O, 6.1 to 6.3 μm if C=C, and 7.7 to 9.6 μm if CO. An additional IR lamp for irradiating IR light of such wavelengths may be provided within the IR lamp unit 105. In other words, the IR lamp 1020 shown in Figure 1 is a lamp for wafer temperature control that irradiates IR light in the near-infrared region (wavelength 0.4 to 3 μm), and additional IR lamps for irradiating IR light of the above wavelength (4 μm or more) may be provided arranged outside the triple IR lamp 1020.

[0036] The stage internal piping 207, located inside the sample stage base material 201, has eight equally spaced circumferential piping points and is positioned directly beneath the ring-shaped downstream gas reservoir 212 formed on the back surface of the gas dispersion plate 208. The stage gas introduction mechanism 206 diffuses the gas supplied from the eight stage internal piping points 207 in the ring-shaped downstream gas reservoir 212 in the circumferential direction of the sample stage 103, and then diffuses it again in the subsequent ring-shaped upstream gas reservoir 214 through 16 evenly spaced slits (inlet ports) 213 at 22.5° intervals. The gas then flows through a fine gap 210 (~0.2 mm) between the inner circumferential wall of the susceptor ring 205 placed on the upper surface of the gas dispersion plate 208 and the outer circumferential side wall 209 of the stage, and into the processing chamber 104 from near the back surface of the wafer 204, thereby suppressing the adhesion of processing gas-induced particles to the stage surface and preventing the adsorbed film (especially at the edges) from reacting with the plasma and being consumed.

[0037] Figure 3 is a schematic cross-sectional view showing the relationship between the gas dispersion plate 208 of the stage gas introduction mechanism 206 of this embodiment shown in Figure 2 and the D-cut 404 of the sample stage base material 201. This figure shows the structure of 1 / 4 of the circumference (a range of 90 degrees around the center of the ring) of the ring-shaped gas dispersion plate 208 shown in Figure 2.

[0038] The gas supplied from the eight internal stage piping 207 of the stage gas introduction mechanism 206 is diffused circumferentially around the sample stage 103 in the downstream gas reservoir 212, which is a ring-shaped space, and then passes through 16 slits (inlets) 213 that are evenly spaced at 22.5° intervals, and is diffused again in the upstream gas reservoir 214, which is a subsequent ring-shaped space. In this way, the gas flow path (path) in the stage gas introduction mechanism 206 is formed so that a non-volatile gas or IR-absorbing gas is blown from the outer circumference of the sample stage 103 toward the side of the central protrusion of the sample stage 103.

[0039] Furthermore, the gas dispersion plate 208, which is processed under high pressure, is made of metal such as SUS because precision in processing is required for the inert gas flow path. In addition, to reduce uneven supply of inert gas, the position of the fine gap 210 between the gas dispersion plate 208 and the outer peripheral side wall 209 of the stage is determined by D-cuts 301 on the gas dispersion plate 208 side and D-cuts 404 on the sample stage base material 201 side, which are of the same shape so that the circumferential variation is within an acceptable range. The position is then fixed to the sample stage base material 201 with screws or bolts, thereby controlling the fine gap 210 between the outer peripheral side wall 209 of the stage and the gas dispersion plate 208 of the sample stage base material 201.

[0040] Figure 4 is a schematic diagram showing the relationship between the recess 401 of the susceptor ring 205 and the slit (inlet) 213 of the gas dispersion plate 208, which constitute the gas flow path of the stage gas introduction mechanism 206 of this embodiment shown in Figure 2.

[0041] A susceptor ring 205 is placed on the upper surface of a gas dispersion plate 208, which is bolted to a stage that forms the flow path of the stage gas introduction mechanism 206. The susceptor ring 205 and the sample stage base material 201 have identical D-cuts 403 on the susceptor ring 205 side and D-cuts 404 on the sample stage base material 201 side, respectively, which are provided for alignment. Using these, the D-cut 403 provided on the inner circumferential wall of the susceptor ring 205 is aligned with the D-cut 404 around the wafer mounting surface of the sample stage base material 201, and the susceptor ring 205 is placed. After placement, the operator uses a gap gauge to center the susceptor ring 205, thereby ensuring a uniform fine gap 210 in the circumferential direction between the susceptor ring 205 and the sample stage base material 201.

[0042] Furthermore, four convex wafer displacement prevention D-shaped protrusions 402, each having a D-cut on the inner circumference, are provided at equal intervals in the circumferential direction on the upper surface of the susceptor ring 205 to support the wafer periphery in the event of wafer displacement of the wafer 204. In addition, three or more recesses 401 are arranged at equal intervals on the inner circumference of the susceptor ring 205, and these recesses are positioned directly above the intermediate positions of the slits (inlet ports) 213 of the stage gas introduction mechanism 206, which are evenly spaced at 22.5° intervals on the gas dispersion plate 208 at the bottom surface.

[0043] The dielectric susceptor ring 205, which is positioned above the metal gas dispersion plate 208 fixed to the sample stage base material 201 with screws and bolts, is not fixed in position relative to the gas dispersion plate 208. It is simply installed by the operator adjusting its position so that the minute gap 210 between its inner circumferential wall and the outer circumferential side wall 209 of the stage is minimized in the circumferential direction. As a result, human error can occur.

[0044] Furthermore, during the heat treatment, the susceptor ring 205 and gas dispersion plate 208 constituting the stage gas introduction mechanism 206 are expected to reach around 200°C due to the heat input, and the quartz susceptor ring 205 is expected to expand by 0.01 mm in the outer diameter direction, and the SUS gas dispersion plate 208 is expected to expand by 0.5 mm in the outer diameter direction. In other words, as multiple wafer processing is performed, the susceptor ring 205 is expected to become eccentric due to the difference in thermal expansion between it and the gas dispersion plate 208, the fine gap 210 becomes non-uniform in the circumferential direction, and the stage gas is expected to have a flow rate bias in the circumferential direction. However, even if the susceptor ring 205 is eccentric in the X and Y directions of the Cartesian coordinate system, and consequently comes into local contact with the outer peripheral wall 209 of the stage, the recesses 401, which are provided at least three equally spaced locations on the inner peripheral edge of the susceptor ring 205, prevent local gas flow stagnation of the inert gas flowing from the fine gap 210 to the processing chamber 104, thereby suppressing circumferential non-uniformity of the stage gas. Figure 5 schematically shows the relationship between a modified example of the recess 401 of the susceptor ring 205 shown in Figure 4 and the slit (inlet) 213 of the gas dispersion plate 208. In Figure 4, the recess 401 is placed at equal intervals on the inner periphery of the susceptor ring 205 at three of the intermediate positions of the 16 slits (inlet) 213 of the stage gas introduction mechanism 206. In Figure 5, the recess 401 is placed at equal intervals on the inner periphery of the susceptor ring 205 at all 16 intermediate positions of the slits (inlet) 213 of the stage gas introduction mechanism 206. In the modified example in Figure 5, the effect of suppressing circumferential non-uniformity of the stage gas can be made more pronounced than in the example in Figure 4. [Examples]

[0045] Figures 6 and 7 show cross-sectional views of modified samples of the sample stage base material 201 that constitutes the gas flow path of the stage gas introduction mechanism 206 of this embodiment shown in Figure 2.

[0046] In the modified example shown in Figure 5, three or more recesses 601 extending vertically are provided at equal intervals in the circumferential direction on the outer peripheral side wall 209 of the sample stage base material 201, which constitutes the micro-gap 210 of the stage gas introduction mechanism 206. To reduce the uneven supply of stage gas to the upper surface of the sample stage base material 201, the position is determined by D-cuts 301 on the gas distribution plate 208 side and D-cuts 404 on the sample stage base material 201 side, which have the same shape, and then the position is fixed to the sample stage base material 201 with screws or bolts, thereby controlling the micro-gap 210 between the outer peripheral side wall 209 of the stage base material 201 and the gas distribution plate 208. Furthermore, the recesses 601 provided on the outer peripheral side wall 209 of the stage base material 201 are positioned in the middle of the 16 slits (inlet ports) 213 of the gas distribution plate 208 that are evenly spaced at 22.5° intervals for the stage gas (inert gas). This prevents localized stagnation of the stage gas flow and suppresses circumferential flow non-uniformity even when the susceptor ring 205 is eccentric in the X and Y directions of the Cartesian coordinate system. Furthermore, in this embodiment 2, the upper surface of the inner peripheral edge of the susceptor ring 205 has a positioning D-cut 403, and the other upper surfaces of the inner peripheral edge have an inner peripheral wall that is smooth in the circumferential direction.

[0047] Furthermore, as shown in the modified example in Figure 7, three or more vertically extending protrusions 701 may be provided at equal intervals in the circumferential direction on the outer peripheral side wall 209 of the sample stage base material 201 that constitutes the fine gap 210 of the stage gas introduction mechanism 206. In addition, the protrusions 701 are positioned to include the intermediate portion of the 16 slits (inlet ports) 213 for inert gas, which are evenly spaced at 22.5° intervals adjacent to each other and fixed to the sample stage base material 201 by four or more bolts at equal intervals. This prevents localized stagnation of gas flow and suppresses circumferential flow rate non-uniformity even if the susceptor ring 205 is eccentric in the X and Y orthogonal coordinate systems. Furthermore, in the embodiment of this second example, the upper surface of the inner peripheral edge of the susceptor ring 205 has a positioning D-cut 403 and has a circumferentially smooth inner peripheral wall.

[0048] Although the present inventors have described the invention in detail based on its embodiments, the present invention is not limited to the above embodiments and can be modified in various ways without departing from its essence. [Explanation of symbols]

[0049] 100...Wafer processing apparatus, 101...Vacuum vessel, 102...Discharge section, 103...Sample stage, 104...Processing chamber, 105...IR lamp unit, 106...Dispersion plate, 107...Quartz chamber, 108...ICP coil, 201...Sample stage substrate, 202...Sample adsorption film, 203...Electrode plate, 204...Wafer, 205...Susceptor ring, 206...Stage gas introduction mechanism, 207...Stage internal piping, 208...Gas dispersion plate, 209...Stage outer peripheral side wall, 210...Microgap, 212...Downstream gas reservoir, 213...Slit (inlet) 214…Upstream gas reservoir, 215…Chiller, 216…Refrigerant flow path, 301…D-cut, 401…Recess, 402…Wafer displacement prevention D-shaped protrusion, 403…D-cut, 404…D-cut, 601…Recess, 701…Convex part, 1011…Plasma, 1013…Processing gas, 1014…Top plate, 1017…Exhaust, 1020…IR lamp, 1021…Reflector, 1022…Light transmission window, 1030…Processing chamber passage.

Claims

1. A processing chamber is located inside a vacuum container and into which processing gas is supplied, A sample stage having a cylindrical shape is placed inside the processing chamber to support the wafer to be processed, The upper part of the sample stage, where the wafer is placed, is surrounded by a stepped portion in a ring shape, A gas dispersion plate having a ring shape that is placed on the bottom surface of the stepped portion and surrounds the aforementioned mounting surface, A susceptor ring placed on the upper surface of the gas dispersion plate and surrounding the aforementioned mounting surface, The gas distribution plate has a gap between the bottom surface and the bottom surface of the stepped portion, the gas distribution plate has a gap between the inner circumferential side wall and the outer circumferential side wall of the stepped portion, and the susceptor ring has a gap between the inner circumferential side wall and the outer circumferential side wall of the stepped portion, forming a flow path through which inert gas flows. A wafer processing apparatus characterized by having recesses extending in the vertical direction at multiple locations on the inner circumferential side wall of the susceptor ring.

2. The wafer processing apparatus according to claim 1, characterized in that the recesses are provided at least three or more locations at equal intervals along the inner circumference.

3. The wafer processing apparatus according to claim 1, characterized in that the gap between the bottom surface of the gas dispersion plate and the bottom surface of the stepped portion is composed of a ring-shaped downstream gas reservoir, a ring-shaped upstream gas reservoir, and a plurality of slits connecting the downstream gas reservoir and the upstream gas reservoir, and the recess is positioned at an intermediate position between the plurality of slits in the circumferential direction.

4. A processing chamber is located inside a vacuum container and into which processing gas is supplied, A sample stage having a cylindrical shape is placed inside the processing chamber to support the wafer to be processed, The upper part of the sample stage, where the wafer is placed, is surrounded by a stepped portion in a ring shape, A gas dispersion plate having a ring shape that is placed on the bottom surface of the stepped portion and surrounds the aforementioned mounting surface, A susceptor ring placed on the upper surface of the gas dispersion plate and surrounding the aforementioned mounting surface, The gas distribution plate has a gap between the bottom surface and the bottom surface of the stepped portion, the gas distribution plate has a gap between the inner circumferential side wall and the outer circumferential side wall of the stepped portion, and the susceptor ring has a gap between the inner circumferential side wall and the outer circumferential side wall of the stepped portion, forming a flow path through which inert gas flows. A wafer processing apparatus characterized by having recesses extending in the vertical direction at multiple locations on the outer peripheral side wall of the stepped portion.

5. The wafer processing apparatus according to claim 4, characterized in that the recesses are provided at least three or more locations at equal intervals along the outer circumference.

6. The wafer processing apparatus according to claim 4, characterized in that the gap between the bottom surface of the gas dispersion plate and the bottom surface of the stepped portion is composed of a ring-shaped downstream gas reservoir, a ring-shaped upstream gas reservoir, and a plurality of slits connecting the downstream gas reservoir and the upstream gas reservoir, and the recess is positioned at an intermediate position between the plurality of slits in the circumferential direction.

7. A processing chamber is located inside a vacuum container and into which processing gas is supplied, A sample stage having a cylindrical shape is placed inside the processing chamber to support the wafer to be processed, The upper part of the sample stage, where the wafer is placed, is surrounded by a stepped portion in a ring shape, A gas dispersion plate having a ring shape that is placed on the bottom surface of the stepped portion and surrounds the aforementioned mounting surface, A susceptor ring placed on the upper surface of the gas dispersion plate and surrounding the aforementioned mounting surface, The gas distribution plate has a gap between the bottom surface and the bottom surface of the stepped portion, the gas distribution plate has a gap between the inner circumferential side wall and the outer circumferential side wall of the stepped portion, and the susceptor ring has a gap between the inner circumferential side wall and the outer circumferential side wall of the stepped portion, forming a flow path through which inert gas flows. A wafer processing apparatus characterized by having multiple protrusions extending in the vertical direction at multiple locations on the outer peripheral side wall of the stepped portion.

8. The wafer processing apparatus according to claim 7, characterized in that the aforementioned protrusions are provided at least three or more locations at equal intervals along the outer circumference.

9. The wafer processing apparatus according to claim 7, characterized in that the gap between the bottom surface of the gas dispersion plate and the bottom surface of the stepped portion is composed of a ring-shaped downstream gas reservoir, a ring-shaped upstream gas reservoir, and a plurality of slits connecting the downstream gas reservoir and the upstream gas reservoir, and the protrusion is positioned at an intermediate position between the plurality of slits in the circumferential direction.

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