Etching treatment method and etching treatment apparatus

Abstract

To provide an etching treatment method and an etching treatment apparatus capable of etching an aluminum oxide film with high precision at a high selectivity ratio with respect to a silicon oxide film and a silicon nitride film, the etching treatment method includes the steps of: arranging a wafer having an aluminum oxide film arranged on an upper surface in a treatment chamber; maintaining the wafer at a temperature of -20°C or lower; and etching the aluminum oxide film by supplying a vapor of hydrogen fluoride from a plurality of through holes of a plate-shaped member arranged above the upper surface of the wafer with a given gap for a predetermined period.

Description

Technical Field

[0001] This invention relates to an etching process method and an etching apparatus, wherein an alumina film of a processing target pre-formed on a substrate such as a semiconductor wafer is etched to remove it during the manufacturing process of a semiconductor device. Background Technology

[0002] In advancing the miniaturization of semiconductor devices, new types of thin films are needed in addition to those already used, such as silicon films, silicon oxide films, and silicon nitride films, to form complex structures. Therefore, there is a strong demand for etching techniques that achieve high selectivity for both the target film and other types of films, based on etching structures formed by stacking such thin films to create circuitry. Alumina films are one example of these new thin film materials.

[0003] use Figure 6 This section illustrates an example of a process for forming a semiconductor device from a film structure utilizing such an alumina film. Figure 6 This is a cross-sectional view schematically illustrating an example of a multilayer film structure containing an alumina film to be etched. The various cross-sectional views in this figure respectively show cross-sections of the film structure in each of the various processes involving the etching step.

[0004] Figure 6 (a) is an example of using an alumina film as an etching mask for the underlying film layer. First, after dry etching the alumina film 601 into a given pattern, the alumina film 601 etched into the shape of that pattern is used as an etching mask to etch the underlying film layer 602. Afterward, as shown in the right image of this figure, the unwanted alumina film 601 is removed, but in this process, a high selectivity is required for the underlying film layer 602, the substrate film 603, etc.

[0005] Figure 6 (b) is an example of using an alumina film as a spacer. If an alumina film 601 is formed on a structure having an upper film 604 on a base film 603, and then etched anisotropically using a dry etching technique, a "spacer" structure can be formed where the alumina film 601 remains only on the side of the structure. After using this spacer structure as a doping mask, outer mask, or pattern mask in the film structure processing, a process is performed to remove the unwanted alumina film 601, as shown in the right figure of this document.

[0006] Figure 6(c) is an example of using an aluminum oxide film as part of a device. In high-performance devices such as logic devices, a "work function metal" is formed to control the work function of the gate oxide film and the gate electrode, and sometimes aluminum oxide is used as part of it. However, the thickness and type of this work function metal are sometimes changed in N-type transistors and P-type transistors, in which case a process is performed to cover one side with photoresist or the like and remove the unwanted parts.

[0007] In the left-hand view of this figure, the aluminum oxide film 601, configured to cover the lower layer 602 of the etched film, forms a functional metal, with the photoresist film 605 configured to cover its left-hand portion. The right-hand portion of the aluminum oxide film 601 is unwanted, and no mask is formed on its surface. In the right-hand view of this figure, the state in which the right-hand portion of the aluminum oxide 601 is selectively removed is shown.

[0008] Figure 6 (d) is an example of using an alumina film as a capacitor insulating film. To avoid the reduction in capacitance associated with miniaturization of capacitors, high dielectric constant materials are sometimes used as capacitor insulating films, and alumina is used as the material for this insulating film. In this figure, a cross-section of a structure in which an alumina film 601 is disposed between an electrode film 605 and a substrate film 603 is shown. Dry etching is mainly used in the processing of the alumina film 601, which matches the pattern of the shape of the upper electrode film 605.

[0009] Regarding the above Figure 6 The process illustrated, as an example of etching to remove the alumina film, can conventionally be performed using a wet process by immersing the film structure in a chemical solution. As an example of such a wet process utilizing a chemical solution, Japanese Patent Application Publication No. 2006-156867 (Patent Document 1) is known. In this example, a technique is disclosed that selective etching is performed by contacting the γ-alumina layer with an etching solution to perform hydrofluoric acid treatment or phosphoric acid treatment.

[0010] Furthermore, Japanese Patent Application Publication No. 8-31932 (Patent Document 2) shows an example of a process in which the alumina film is removed by using a hot phosphoric acid solution, thereby not removing the tungsten film and silicon oxide film beneath the alumina film, but leaving only the tungsten film within the contact hole 14. Furthermore, Japanese Patent Application Publication No. 8-236503 (Patent Document 3) discloses that a wet etching method for alumina based on an aqueous phosphoric acid solution is conventionally known.

[0011] However, in such wet etching processes, the miniaturization of semiconductor device fabrication has led to problems such as deformation of the circuitry formed on the wafer surface due to the surface tension of the etching solution, pattern collapse (e.g., the collapse of the walls between trenches), and etching residues in trenches, holes, and gaps. Furthermore, the need for large amounts of etching solution becomes problematic. Therefore, there is a demand to replace isotropic etching with wet etching using etching solutions with dry etching processes that do not require etching solutions.

[0012] On the other hand, as an example of dry etching of such alumina films, Japanese Patent Application Publication No. 8-236503 (Patent Document 3) discloses a technique for etching alumina films using plasma formed by a gas containing boron trichloride gas, fluorine-containing saturated or unsaturated hydrocarbon gas, and CO gas or CO2 gas; or a gas containing boron trichloride gas and at least one gas selected from lower alcohols and saturated or unsaturated hydrocarbons with 1 to 5 carbon atoms. Furthermore, Japanese Patent Application Publication No. 59-56731 (Patent Document 4) discloses an example of etching alumina films using plasma formed by etching gases such as CCl4, BCl3, Cl2, and SiCl4.

[0013] However, in the aforementioned prior art, ion-assisted etching is used to induce collisions between charged particles such as ions from the plasma and the alumina film to be etched, thus promoting anisotropic etching. Therefore, it is difficult to use in removal processes that require isotropic etching.

[0014] On the other hand, as an example of a technology that uses only gas to remove alumina, the technology disclosed in Japanese Patent Application Publication No. 3-272135 (Patent Document 5) is known. In this prior art, the alumina film is removed by reacting with ClF3 gas, and the temperature in the chamber is set to 200°C and the pressure is set to 9 Torr.

[0015] Furthermore, in Y. Lee, J.W. Dumont and S.M. George, "Mechanism of Thermal Al2O3 Atomic Layer Etching Using Sequential Reactions with Sn(acac)2 and HF", Chemistry of Materials, 27, 3648 (2015) (Non-Patent Literature 1), a method for etching alumina by repeated irradiation with tin complex and hydrogen fluoride was proposed. However, the low vapor pressure of tin complex makes it ineffective in practical etching. Moreover, since a high temperature above 200°C is required, it is difficult to avoid the aforementioned diffusion and corrosion problems.

[0016] Prior art literature

[0017] Patent documents

[0018] Patent Document 1: JP 2006-156867

[0019] Patent Document 2: JP 8-31932

[0020] Patent Document 3: JP 8-236503

[0021] Patent Document 4: JP Japanese Patent Application Publication No. 59-56731

[0022] Patent Document 5: JP Japanese Patent Application Publication No. 3-272135

[0023] Non-patent literature

[0024] Non-patent document 1: Y. Lee, JW Dumont and SM George, "Mechanism of ThermalAl2O3 Atomic Layer Etching Using Sequential Reactions with Sn(acac)2and HF", Chemistry of Materials, 27, 3648 (2015) Summary of the Invention

[0025] The problem the invention aims to solve

[0026] The aforementioned prior art has problems because it does not adequately consider the following points.

[0027] In other words, as semiconductor devices advance miniaturization, research is underway on 3D logic devices such as FinFET and Gate-All-Around, as well as 3D-DRAM and 3D-NAND processes for memory devices. However, to achieve high-precision nanoscale fabrication of these complex structures, the existing three thin films—silicon film, silicon oxide film, and silicon nitride film—are insufficient for device fabrication, necessitating microfabrication and stripping processes using alumina. Therefore, there is a strong demand for a technology that strips only alumina while leaving the silicon film, silicon oxide film, and silicon nitride film almost entirely unetched.

[0028] However, the existing alumina film stripping techniques described above, in wet etching processes based on hydrofluoric acid or phosphoric acid solutions, can result in etching residues and pattern collapse in structures with finely spaced grooves and tiny-diameter holes, making it impossible to form accurate circuit structures and leading to a decrease in yield. Furthermore, the aforementioned existing techniques use ion-assisted etching, where charged particles such as ions from plasma based on boron trichloride are attracted to the alumina film to be etched, causing collisions and promoting anisotropic etching. Therefore, isotropic etching is difficult to achieve.

[0029] Furthermore, the technology disclosed in Patent Document 5 requires maintaining a high temperature of 200°C within the chamber. This would cause chlorine atoms to diffuse not only into the alumina but also into adjacent materials, raising concerns about corrosion and degradation of device properties. Thus, in existing technologies, it is impossible to remove the alumina film isotropically, resulting in compromised processing precision and yield. Such issues have not been adequately addressed.

[0030] The present invention was made in view of the above-mentioned problems, and provides an etching process method and an etching process apparatus capable of etching an alumina film with high precision at a high selectivity ratio relative to a silicon oxide film and a silicon nitride film.

[0031] Methods for solving problems

[0032] The above objective is achieved by an etching process comprising the following steps: placing a wafer with an alumina film on its upper surface in a processing chamber, maintaining the wafer at a temperature below -20°C, and supplying hydrogen fluoride vapor from multiple through holes in a plate-shaped member with a given gap above the upper surface of the wafer for a predetermined period of time to etch the alumina film.

[0033] Furthermore, this is achieved using an etching apparatus comprising: a vacuum container; a stage disposed within the space inside the vacuum container and on the upper surface of a wafer for which an alumina film is pre-formed; a plate member disposed on the stage with a given gap between the wafer and the alumina film above the wafer, and having a plurality of through holes for introducing vapor of a processing gas containing hydrogen fluoride into the alumina film containing the gap; and a temperature regulating mechanism for regulating the stage or the wafer to a temperature of -20°C or below.

[0034] Invention Effects

[0035] An etching method or etching apparatus can be provided that can etch an alumina film at a faster etching rate than a silicon oxide film or a silicon nitride film, and can remove the alumina film by etching with high selectivity and high precision. Attached Figure Description

[0036] Figure 1 This is a schematic longitudinal cross-sectional view illustrating the structure of the etching processing apparatus according to an embodiment of the present invention, which includes the main part of a wafer disposed in the processing chamber.

[0037] Figure 2 This is a schematic longitudinal cross-sectional view illustrating the structure of the etching processing apparatus involved in this embodiment.

[0038] Figure 3 This is a schematic longitudinal cross-sectional view illustrating the structure of an etching processing apparatus according to another embodiment of the present invention.

[0039] Figure 4 This is a schematic longitudinal cross-sectional view illustrating the structure of an etching processing apparatus according to a further embodiment of the present invention.

[0040] Figure 5 It means Figure 2 A top view of the structure of the gas cluster plate of the etching process apparatus involved in the illustrated embodiment.

[0041] Figure 6 This is a cross-sectional view schematically illustrating an example of a multilayer film structure containing an alumina film to be etched.

[0042] Figure 7 It is a graph representing the etching amount of multiple types of coatings on the sample surface. Detailed Implementation

[0043] The embodiments of the present invention are illustrated below using the accompanying drawings.

[0044] The embodiments of the present invention are based on the following insight: in a corrosion test in which hydrogen fluoride and methanol gas are introduced into a chamber, when an alumina material is placed face down on a silicon wafer, the ends of the material are etched.

[0045] Specifically, in order to evaluate the etching process using hydrogen fluoride and methanol gas on silicon oxide films, the inventors evaluated the corrosion resistance of alumina films, which could potentially be used as materials to constitute the processing chamber. As evaluation samples, a group of three components—a silicon nitride film, a silicon oxide film, and an alumina film—were formed on a flat surface with an area smaller than the upper surface of the sample wafer. Each film was placed upwards on the upper surface of the silicon wafer and secured with polyimide tape. Furthermore, another group of samples was placed on the upper surface of the silicon wafer with the films disposed on the surfaces of each component facing downwards (towards the upper surface of the silicon wafer) and secured in the same manner.

[0046] After the silicon wafers containing the six etched samples were introduced into the processing chamber and placed on the stage within the chamber, 400 sccm of hydrogen fluoride, 200 sccm of methanol, and 100 sccm of argon gas were introduced into the sealed processing chamber. The pressure within the processing chamber was regulated using a butterfly valve and maintained at 300 Pa. The silicon wafers were held on the stage within the processing chamber for 120 seconds while maintaining a temperature of -35°C.

[0047] Figure 7 The results show the results of detecting the amount of etching on the surface coating of subsequent samples. Figure 7 It is a graph representing the etching amount of multiple types of coatings on the sample surface.

[0048] For the silicon nitride film of the sample, the etching depth is approximately less than 5 nm in both the method of mounting the film facing upwards on the sample wafer and the method of mounting it facing downwards. On the other hand, for the silicon oxide film, the etching depth is more than 80 nm in the method of mounting the film facing upwards on the sample wafer, but less than 5 nm in the method of mounting the film facing downwards.

[0049] Furthermore, for alumina films, placing the coating upwards on the sample wafer results in deposition on the wafer, thus increasing the film thickness. On the other hand, placing it downwards on the sample wafer results in almost no etching at the center of the coating on the downward-facing surface of the sample, but less than 20 nm of etching at the periphery. The etching at the periphery occurs in a region approximately 2 mm towards the center from the outer periphery cut from the flat downward-facing surface of the etched sample. Furthermore, it was determined that a selectivity of 4 degrees was ensured for both silicon oxide and silicon nitride films under the same conditions.

[0050] According to the inventors' research, it was determined that the etching of the aforementioned alumina film occurs at the periphery of the film when the sample is placed on the upper surface of a sample wafer at a temperature of -35°C and supplied with HF + CH3OH gas, with the sample flattened and facing the upper surface of the sample wafer, particularly with a narrow gap. This phenomenon is believed to be caused by the partial condensation of hydrogen fluoride on the low-temperature upper surface of the sample wafer and the surface of the sample covered by the alumina film, with the narrow gap between them. The condensed hydrogen fluoride liquid or molecules enter the narrow gap between the alumina film and the silicon wafer from the outer peripheral edge of the sample surface through capillary action, thereby etching the alumina film up to approximately 2 mm from the outer peripheral edge.

[0051] Based on the results of this study, the distance between a wafer capable of etching an alumina film disposed on its surface and the plane opposite it was investigated. The following formula is known as a representation of the range in which capillary action occurs.

[0052] h=2Tcosθ / pgr

[0053] Here, h is the penetration height, T is the surface tension, cosθ is the contact angle, ρ is the density, g is the gravitational acceleration, and r is the inner diameter of the tube. The physical properties of liquid hydrogen fluoride are detailed in "Anhydrous Hydrogen Fluoride," Organic Synthesis Chemistry, Vol. 25, No. 12, pp. 1176-1191 (1967), by Murahashi Shunsuke and Sakakibara Shunpei. Based on this, the surface tension is weaker than that of water, set at 0.012 N / m (-23°C), and the density of liquid hydrogen fluoride is set to approximately the same as that of water, 1002 kg / m³. 3 Since the contact angle is unknown, and the measured value of h is 2mm, if the same value as that for water is used, then r, which is equivalent to the inner diameter of the pipe, is 1.15mm. Therefore, it can be said that the distance between the wafer and the opposing surface is preferably less than 1mm.

[0054] As described above, the following is obtained as an insight: the membrane structure is supplied with hydrogen fluoride + methanol as an etching gas, and the membrane structure is maintained at a temperature range of -20°C to -50°C, preferably at -35°C, as a processing condition for etching an alumina film with a high selectivity ratio relative to silicon oxide film and silicon nitride film, and the surface of the surface forming a gap of less than 1 mm has an alumina film.

[0055] use Figure 1 The characteristic structure of the embodiments of the present invention will be explained below. Figure 1 This is a schematic longitudinal cross-sectional view illustrating the structure of the etching apparatus according to an embodiment of the present invention, which includes the main part of a wafer disposed in the processing chamber.

[0056] In this figure, a longitudinal section near the upper surface of a wafer is schematically shown in a state where it is placed on a stage (not shown) within a processing chamber. In this figure, an aluminum oxide film 101 is disposed on the upper surface of the wafer substrate 102, and a gas jet plate 103 having a plurality of through holes 104 is disposed above its surface with gaps 105.

[0057] Furthermore, the surface of the alumina film 101 and the lower surface of the gas jet plate 103 are arranged opposite each other, and the distance between the lower surface of the gas jet plate 103 and the upper surface of the alumina 101 or the substrate 102 extends over the entire area of ​​these surfaces and is maintained at a value approximately equal to a given value, except for the opening portion at the lower end of the through hole 104, where they are parallel or considered parallel. In particular, in this example, the aforementioned distance, i.e., the size (distance) T of the gap 105 between the lower surface of the gas jet plate 103 and the alumina 101, is maintained at less than 1 mm.

[0058] The gas jet plate 103 has a plurality of through holes 104 through which a processing gas such as hydrogen fluoride for etching the alumina film 103 is supplied. In this embodiment, the gap T between the gas jet plate 103 and the substrate 102 or the upper surface of the alumina film 101 is set to a value of 3 mm or less, preferably 1 mm or less.

[0059] Furthermore, the distance between the lower openings of two adjacent through holes 104 of the gas jet plate 103, or the length of the lower surface of the gas jet plate 103 between them, or the distance D between the lower opening of the through hole 104 and the outer peripheral edge of the gas jet plate 103, is set to a value between 1 mm and 3 mm, preferably 2 mm. In addition, the diameter of the through hole 104 is set to a value within the range of 1 mm and 3 mm, preferably 2 mm. Furthermore, quartz is used as the material constituting the gas jet plate 103, but it is not limited to this; other ceramic materials, resin materials, and other materials with relatively low reaction with hydrogen fluoride vapor and low consumption can be used.

[0060] In this embodiment, the pressure in the gap between the gas jet plate 103 and the substrate 102 or the alumina film 101 is maintained at several hundred Pa, preferably at 300 Pa. To achieve this, the supply, exhaust flow rate, or speed of the processing gas is adjusted. The supplied processing gas is not limited to hydrogen fluoride, but may also include alcohols such as methanol, rare gases, and other gases.

[0061] Furthermore, although not shown, the alumina film 101 and the substrate 102 are placed and held on a support mechanism such as a wafer stage, which has a flow path for the cooling medium connected to a device such as a cooler for regulating the temperature of the cooling medium internally. By adjusting the support mechanism to a temperature within a given range using an internal temperature regulating mechanism, the temperature of the substrate 102 on which the alumina film 101 is disposed is maintained at a value suitable for etching the alumina film 101, between -20°C and -50°C, preferably at -35°C. The etching process of the alumina film 101 occurs when a processing gas supplied from the gas jet plate 103 condenses hydrogen fluoride vapor or forms droplets and reacts within the gap 105.

[0062] Example 1

[0063] The following is based on Figure 2 The embodiments of the present invention will be described in detail. Figure 2 This is a schematic longitudinal cross-sectional view illustrating the structure of the etching processing apparatus involved in this embodiment.

[0064] In this figure, the etching processing apparatus 200 generally comprises: a vacuum chamber 1 having a cylindrical space with reduced pressure inside, namely a processing chamber 5; a gas line 2 having piping and valves connected to the vacuum chamber 1 for introducing gas into the processing chamber 5; and an exhaust section 3 having a vacuum pump connected to the bottom surface of the vacuum chamber 1 and communicating with the processing chamber 5 to discharge gases, compounds, and other particles from the processing chamber 5 to the outside of the processing chamber 5. The vacuum chamber 1 has a cylindrical metal vacuum container, namely a top chamber 11, having a central axis in the vertical direction, and a bottom chamber 12 connected to the top chamber 11 below it. The cylindrical processing chamber 5 is arranged inside the bottom chamber 12, and a cylindrical stage 15 is arranged in the center of the lower part of the processing chamber 5 for placing the wafer 14 to be processed on its upper surface. The stage 15 has a dielectric coating that forms a circular upper surface similar to that of the wafer 14, which has a circular plate shape, and has a flow path (not shown) that circulates internally to supply a cooling medium so that the wafer 14 placed on the stage 15 can be cooled to a low temperature of -20°C or below.

[0065] The upper part of the bottom chamber 12 is formed by an annular member covering the processing chamber 5, and the top chamber 11 is placed at its center, connecting the two. In this embodiment, the cylindrical top chamber 11 is connected to the gas line 2, and has a buffer chamber 4 inside that communicates with the gas line 2 and is supplied with gas for processing. The gas supplied to the buffer chamber 4 diffuses inside it.

[0066] A gas jet plate 103, made of a dielectric material such as quartz, with a circular plate shape, is disposed between the buffer chamber 4 inside the top chamber 11 and the processing chamber 5 inside the bottom chamber 12. The gas jet plate 103 divides the two chambers into upper and lower sections and connects them through a plurality of through holes disposed in the jet plate 13. In this embodiment, the gas jet plate 103 is a circular plate-shaped component inserted into the communication path between the processing chamber 5 and the buffer chamber 4, including a circular through hole in the center of a metal plate member with an annular shape that forms the cover of the bottom chamber 12. It is configured such that its lower surface faces the upper surface of the platform 15 below at the lower end of the communication path to form the top surface of the processing chamber 5.

[0067] An exhaust port 16, which constitutes the exhaust section 3 and connects the processing chamber 5 to the outside, is disposed at the bottom of the bottom chamber 12. Gas and product particles in the processing chamber 5 are discharged to the outside through the exhaust port 16 by the operation of the vacuum pump of the exhaust section 3.

[0068] Furthermore, in this embodiment, the stage 15 is connected via piping to a cooler 17 that regulates the temperature of a cooling medium (refrigerant) flowing through its internal flow path to a value within a given range. The refrigerant circulates between the temperature-regulating cooler 17 and the flow path within the stage 15 according to the operation of a pump (not shown), thereby maintaining the temperature of the stage 15 and consequently the temperature of the wafer 14 on its upper surface at -20°C or below. In regulating the temperature of the wafer 14, not only can the circulation of the temperature-regulated refrigerant be used, but also any one or a combination of conventionally known temperature regulation methods can be employed, such as using an electrostatic or mechanical chuck to hold the wafer 14 in contact with the upper surface of the stage 15, promoting heat transfer through a conductive gas supplied between them, utilizing heating or cooling elements such as a Peltier element built into the stage 15, or heating from radiation from a lamp positioned above the stage 15.

[0069] The gas line 2 shown in the diagram is connected to the upper surface of the top chamber 11, and the processing gas flowing inside is introduced into the interior from the upper part of the buffer chamber 4. In this embodiment, gas line 2 is used with hydrogen fluoride gas and alcohols such as methanol and ethanol (C60-400 ppm) as the processing gas. x H y The gas sources required for etching alumina films such as OH) are connected to the gas storage units 33 and 34. Various gases from the gas storage units 33 and 34 are regulated to a suitable range for processing by mass flow components 21 equipped with valves and pressure gauges that open or close or increase or decrease the cross-sectional area of ​​flow paths arranged on the gas lines 2 that are connected to them.

[0070] Furthermore, in this example, the result of connecting multiple pipes configured for each of these multiple types to the connection between the mass flow component 21 and the top chamber 11 is that a single pipe, connected to the top chamber 11, flows through the interior to form a mixed gas that allows the multiple types of gases to merge and mix. This gas mixing can occur not only at a location closer to the mass flow component 21 than the connection to the top chamber 11, but also within the top chamber 11, where multiple pipes connecting the various gases constituting the processing mixed gas flow through the interior, allowing diffusion and mixing within the buffer chamber 4, resulting in a composition with a partial pressure or molar ratio suitable for processing. The types of gases used in the processing mixed gas of this embodiment described below can be any gas, including but not limited to hydrogen fluoride vapor, methanol vapor, and other alcohols, such as argon, nitrogen, helium, and other gases required for etching alumina films.

[0071] The exhaust section 3 includes an exhaust port 16 and is equipped with a mechanical booster pump 32 driven to expel particles from the processing chamber 5 and reduce the pressure inside the processing chamber 5, and a butterfly valve 31 disposed on the exhaust pipe connecting them and adjusting the flow rate or speed of the exhaust by increasing or decreasing the cross-sectional area of ​​the internal exhaust flow path. The butterfly valve 31 has multiple plate-shaped flaps that rotate about an axis disposed in a direction traversing the exhaust pipe. The flow rate or speed of the exhaust is increased or decreased by increasing or decreasing the rotation angle of these flaps about the axis. The pressure in the processing chamber 5 and the buffer chamber 4 is adjusted according to the balance between the amount or speed of the processing gas supplied from the gas line 2 and the amount or speed of the exhaust from the exhaust section 3 originating from the processing chamber 5.

[0072] The unit for regulating the amount of exhaust gas used to regulate the pressure of the treatment chamber 5 or the buffer chamber 4 is not limited to the butterfly valve 31, and other units may also be used. Furthermore, the unit for venting exhaust gas from the treatment chamber 5 is not limited to the mechanical booster pump 32, and rotary pumps, dry pumps, turbomolecular pumps, or combinations thereof may also be used.

[0073] use Figure 5 An example illustrating the shape of a gas jet plate 103 disposed between the top chamber 11 and the bottom chamber 12 and within a communication path connecting the buffer chamber 4 and the processing chamber 5 disposed within their respective chambers. Figure 5 It means Figure 2 The top view of the structure of the gas jet plate of the etching process apparatus involved in the embodiment shown is a diagram showing the shape when viewed from the upper part of the central axis in the vertical direction of the circular gas jet plate 103.

[0074] Furthermore, the gas shower plate 103 in this figure is made of quartz and is a circular plate member with a fixed or approximately fixed thickness in the radial direction. It has multiple through holes 104, and is symmetrical about a central axis in both the shape of the circular plate and the position of the through holes 104. It also has a structure that is symmetrical about the horizontal direction (in-plane direction) with respect to the axis that will pass through it. Therefore, the area on the right side of the figure is omitted.

[0075] The openings on the upper or lower surface of each of the plurality of through holes 104 in the gas shower plate 103 are arranged with a gap (distance) of 1 mm to 3 mm relative to the openings on the upper or lower surface of adjacent through holes 104. Furthermore, each through hole 104 has a cylindrical shape with a fixed diameter in the vertical direction, the diameter being a value in the range of 1 mm to 3 mm. In this embodiment, based on the experimental results of the inventors, the through holes 104 are arranged with a 2 mm interval, which yields more preferred results in the etching of the alumina film, and have a diameter of 2 mm. Furthermore, the structure of the through holes 104 is not limited to a cylindrical shape with a single diameter.

[0076] Furthermore, in Figure 5 In the illustrated embodiment, a plurality of through holes 104 are arranged at given intervals on a line segment axis extending radially from the center towards the outer peripheral edge, excluding the central axis and the outer peripheral edge. Furthermore, the plurality of through holes 104 on such a line segment axis have a radial arrangement arranged around the central axis in the vertical direction at each given angle. The arrangement of the through holes 104 is not limited to this radial arrangement; they can also be arranged in a so-called lattice pattern, with the central axis of the through holes 104 located at the intersection of a plurality of mutually perpendicular axes in the left-right and vertical directions shown in the figure.

[0077] The thickness of the gas jet plate 103 is set to a thickness that does not cause damage to a material when the pressure in the buffer chamber 4 of the top chamber 11 is between 2 and 10 times the pressure in the processing chamber 5 of the bottom chamber 12. Although quartz is used as the material for the gas jet plate 103, any other material, such as ceramics or plastic resins, that reacts relatively little with hydrogen fluoride vapor can be used.

[0078] In this embodiment, as Figure 1As shown, the distance between the gas cluster plate 103 and the upper surface of the wafer 14 placed on the stage 15 is set to 1 mm or less. On the other hand, in order to form extra space (allowance) to prevent the robotic arm and handling device used for handling the wafer 14 from colliding with the stage 15 and the gas cluster plate 103 during wafer handling, the aforementioned allowance is ensured by connecting the gas cluster plate 103 or the stage 15 to a mechanism that moves it, and by moving the gas cluster plate 103 upward or the stage 15 downward during wafer handling. In either case, after the wafer 14 is handled, the distance between the gas cluster plate 103 and the stage 15 is reduced again, and the distance between the upper surface of the wafer 14 and the lower surface of the gas cluster plate 103 is set to 1 mm or less while the wafer 14 is placed on the stage 15, thus fixing their positions.

[0079] Furthermore, in this embodiment, the various components of the etching apparatus 200, such as the stage 15 or gas jet plate 103, cooler 17, mass flow assembly 21, butterfly valve 31, mechanical booster pump 32, and gas storage units 33 and 34, are connected to the control unit 35 in a communicable manner. The control unit 35 sends instruction signals to each component, corresponding to signals output from these components indicating their operational status and signals indicating that status. The control unit 35 is configured to include: an interface unit containing a connector for transmitting and receiving the aforementioned signals and a converter for converting signals into other given signals; an arithmetic unit containing an arithmetic unit such as a semiconductor microprocessor; and a storage device unit such as a semiconductor memory, CD-ROM, DVD-ROM drive, or hard disk, all connected in a signal communication manner.

[0080] The control unit 35 is disposed in any of the aforementioned units and receives detection signals from sensors indicating the state of its operation. The arithmetic unit reads software stored in the storage device and detects the state of the operation from the detection signals based on its algorithm. Further, based on the comparison between the detected result and the desired value, a command signal indicating the operation of the desired value based on the algorithm of the software in the storage device is calculated, and the command signal is sent from the interface of the control unit 35 to one of the units. The unit receiving the command signal adjusts itself based on the signal so that its operation state approaches the desired value that is the target. Unless otherwise specified, the other embodiments described below are the same.

[0081] The etching process in this embodiment is explained. The wafer 14 is transported within a vacuum transport chamber (not shown), a vacuum transport container connected to the side wall of the bottom chamber 12, under reduced pressure. It is then transported into the processing chamber 5 of the bottom chamber 12 through a gate, a passageway that horizontally extends through the side wall of the bottom chamber 12. Afterward, it is transferred to a stage 15 and placed in contact with the upper surface of the stage 15. Direct current is supplied to electrodes for electrostatic adsorption within a dielectric film (not shown) constituting the upper surface, and the wafer 14 is held on the stage 15 by electrostatic force. A heat-transferring gas, such as He, is supplied to the gap between the back surface of the wafer 14 and the upper surface of the stage 15. Heat is transferred between the wafer 14 and the stage 15, which is cooled to a given value within the range of -20°C to -50°C. As a result, the temperature of the wafer 14 is brought to a value within a suitable processing range, equivalent to that of the stage 15.

[0082] The aforementioned wafer 14 can be held using either electrostatic adsorption or mechanical adsorption. In this state, the temperature of the stage 15 is set to -35°C using a refrigerant whose temperature is regulated by the cooler 17. At this time, no processing gas is supplied to the processing chamber 5 until the control unit 35 detects that the temperature of the wafer 14 has reached a predetermined suitable processing temperature (-35°C in this example) based on the output of a temperature sensor (not shown) disposed inside the stage 15.

[0083] If the control unit 35 confirms that the temperature of the stage 15 has dropped to the temperature determined by the cooler 17, based on the command signal from the control unit 35, the gas from the storage section 33 or 34 of the gas line 2 is introduced into the buffer chamber 4 in the top chamber 11 through the piping within the gas line 2, as a processing gas containing hydrogen fluoride and alcohol. For example, in this example, 400 sccm of hydrogen fluoride, 200 sccm of methanol, and 100 sccm of argon are introduced into the buffer chamber 4. Furthermore, while these gases are continuously supplied from the gas line 2 to the buffer chamber 4, with the mechanical booster pump 32 driven, the butterfly valve 31 operates in response to the command signal from the control unit 35 to adjust the exhaust flow rate or speed, so that the pressure in the processing chamber 5 is within a predetermined allowable range of 300 Pa. In addition, although not shown, pressure sensors for detecting the pressure in the buffer chamber 4 or the processing chamber 5 are installed in the top chamber 11 and the bottom chamber 12, and can communicate with the control unit 35.

[0084] The processing gas introduced into the buffer chamber 4 passes through the through hole 104 of the gas jet plate 103, and thus flows from the opening at the lower end of the through hole 104 into the space between the alumina film surface on the upper surface of the wafer 14 and the lower surface of the gas jet plate 103 in the processing chamber 5. Figure 1The gap 105 shown indicates the supply of processing gas. According to the inventors, there is a linear correlation between the time of supplying the processing gas and the amount of alumina etching. Therefore, the control unit 35 adjusts the operation of the valves on the mass flow component 21 or the gas line 2 to supply the processing gas into the processing chamber 5 for a predetermined time based on the aforementioned correlation. In response to the command signal from the control unit 35, the supply of processing gas is stopped, and the processing of the alumina film on the wafer 4 is halted.

[0085] Following this, the operation of the exhaust unit 3 continues, performing a high-vacuum exhaust process to further reduce the pressure to a level sufficiently higher than the vacuum level in the etching process performed inside the buffer chamber 4 and processing chamber 5. Through this process, the processing gases, compounds generated in the previous processing, and byproducts inside the processing chamber 5 are fully exhausted. Afterward, the wafer 14 is released from its adsorption-based holding position and transferred to a transport device such as a robotic arm that has entered the processing chamber 5 from the vacuum transport chamber, removing it from the stage 15 and moving it outside the processing chamber 5. Then, depending on whether there are any unprocessed wafers 14 that should be processed next, the control unit 35 determines whether to continue or stop the processing of the wafer 14 performed by the etching apparatus 200.

[0086] Alternatively, the following process can be performed as a single wafer processing cycle, repeated multiple times until the desired etching depth is achieved. The process is: etching of the alumina film by introducing processing gas into the processing chamber 5 for a given period while maintaining a gap of a given distance between the wafer 14 and the gas jet plate 103; and high-vacuum exhaust of the gas and particles following this process.

[0087] Example 2

[0088] Next, use Figure 3 The summary will be given with reference to another embodiment of the present invention. Figure 3 This is a schematic longitudinal cross-sectional view illustrating the structure of an etching processing apparatus according to another embodiment of the present invention. In the etching processing apparatus 300 of Embodiment 2, a structure is provided that promotes the etching of an alumina film and the removal of residues on its surface by using plasma.

[0089] In this example, for with Figure 2 Structures shown in the accompanying drawings that are identical in designation are omitted from the description unless there is a necessary difference in structure.

[0090] The etching apparatus 300 of this embodiment differs from the etching apparatus 200 of Embodiment 1 in that, in this embodiment, a cylindrical top chamber 11' with a height greater in the vertical direction than the top chamber 11 of Embodiment 1 is placed above the central portion of the annular cover portion constituting the upper part of the bottom chamber 12. Furthermore, as cylindrical sidewalls, the top chamber 11' has quartz dielectric tubes 301 with cylindrical inner circumferential sidewalls of the same diameter disposed between the upper and lower cylindrical metal components. Besides quartz, ceramic materials such as alumina, silicon carbide, and aluminum nitride can be used as the material for the dielectric tube 301.

[0091] The upper and lower ends of the dielectric cylinder 301 are similarly provided with metal annular members that form the side wall portion of the top chamber 11'. Between the dielectric cylinder 301 and these metal annular members, vacuum seals such as O-rings are deformed by being sandwiched and held between the upper and lower parts, thus dividing the internal space from the external top chamber 11' which is surrounded by an atmospheric pressure atmosphere.

[0092] Furthermore, around the cylindrical outer peripheral wall of the dielectric cylinder member 301, a discharge coil antenna 302 wound around it is positioned with a gap between it and the outer peripheral wall. The coil antenna 302 is electrically connected to a high-frequency power supply 304 that supplies high-frequency power via a matching component 303. Figure 3 In this case, the antenna 102 can be wound only once, but it can also be wound twice or three times or more, and can be further wound in multiple stages in the vertical direction.

[0093] In this embodiment, the top chamber 11' has a cylindrical space inside, and the cylindrical sidewalls of the top chamber 11' containing the dielectric cylinder member 301 surround the space. Further, by supplying high-frequency power to the coil antenna 302 wound around the outer periphery of the dielectric cylinder member 301, an induced magnetic field is formed within the cylindrical interior space. Atoms or molecules of the gas supplied from the gas line 2, connected to the circular cover member of the top chamber 11', are excited by the induced current generated by the induced magnetic field, resulting in dissociation and ionization to form plasma. Thus, the cylindrical space inside the top chamber 11' in this example is a discharge chamber 305 for forming plasma.

[0094] The etching process of the wafer 14 in the etching process apparatus 300 of Embodiment 2 is explained. In this embodiment, plasma is generated by exciting the processing gas supplied to the space in the top chamber 11, i.e., the discharge chamber 305, by the induced magnetic field induced by the high-frequency power supplied to the coil antenna 302. The particles of this plasma are used to promote the etching of the alumina film or to remove surface residues.

[0095] Similar to Embodiment 1, after the wafer 14 is transported to the processing chamber 4 within the bottom chamber 12, it is held on the stage 15. The control unit 35 detects whether the temperature of the stage 15 or the wafer 14 is set to a value within a suitable range for processing, including a given temperature such as -30°C. In this embodiment, the introduction of processing gas into the discharge chamber 305 or the formation of plasma is not performed until the temperature is detected to be within a suitable range for processing.

[0096] In this embodiment, if the oxidation state of the alumina film surface is determined to be insufficient, while the wafer 14 is held on the stage 15, oxygen is supplied from the gas line 2 to the discharge chamber 305 inside the top chamber 11', and plasma utilizing this oxygen is formed in the discharge chamber 305. Particles formed in this plasma are then supplied to the alumina film on the surface of the wafer 14 in the processing chamber 5 through the through-hole 104 of the gas shower plate 103, thereby performing plasma-based particle-based surface oxidation. By performing this surface oxidation process, the unevenness of the oxidation state on the alumina film surface is reduced and rectified, enabling etching that further reduces surface roughness.

[0097] As an example of conditions for forming oxygen-utilized plasma, oxygen is introduced into the discharge chamber 305 at 100 sccm, and the internal pressure is set to 50 Pa. Under these conditions, high-frequency power is supplied from the high-frequency power supply 104 to the coil antenna 302, exciting the oxygen and causing it to ionize and dissociate, thereby forming plasma. In this embodiment, oxygen plasma particles are supplied to the alumina film on the upper surface of the wafer 14 through the through-hole 104 of the gas shower plate 103, with a portion entering the gap between the gas shower plate 103 and the alumina film of the wafer 14 and spreading throughout the surface of the alumina film, initiating an oxidation reaction. This introduction of particles into the plasma takes 15 seconds.

[0098] After the oxygen plasma irradiation process, the discharge chamber 305 and processing chamber 5 are depressurized and vented to a high vacuum level, and the gas is replaced. Then, hydrogen fluoride gas is introduced into the discharge chamber 305 through gas line 2 to perform the same alumina film etching process as in Example 1. Further, similar to Example 1, after supplying processing gas for a given time, the control unit 35 sends a command signal to the mass flow component 21 or the valve on the gas line 2 to stop the gas supply, thereby stopping the alumina film etching process. Further, after the exhaust unit 3 continues to ventilate and depressurizes the discharge chamber 305 or processing chamber 5 to a high vacuum level to fully exhaust the internal gas and particles, the wafer 14 is released from its attachment on the stage 15 and moved from the stage 15 through the gate opened on the side wall of the bottom chamber 12 to the vacuum transport chamber outside the processing chamber 5.

[0099] Furthermore, in the example of processing wafer 14 described above, each process involves one oxidation step of an alumina film based on oxygen plasma and one etching step of an alumina film using hydrogen fluoride. However, after performing the etching step of the alumina film and venting to a high vacuum, a cyclic etching process, comprising at least one repeat of the following steps, can also be performed: an oxidation step of introducing oxygen into the discharge chamber 305 to form oxygen plasma; a subsequent high vacuum venting step; and an etching step of the alumina film based on hydrogen fluoride. Alternatively, before the etching step performed with hydrogen fluoride gas, after performing one alumina film oxidation step, a cyclic etching process, comprising at least one repeat of the following steps, can be performed: the etching step and a high vacuum venting step of venting the processing chamber 5 or the discharge chamber 305 to a high vacuum level before or after it.

[0100] Furthermore, in the event of insufficient fluorine supply based on hydrogen fluoride (HF) gas, as one step in the overall process cycle described above, a process can be performed whereby a fluorinated alumina film surface is fluorinated by introducing a fluorinated hydrocarbon gas into the discharge chamber 305 to form a plasma, after the wafer 14 has been placed and held on the stage 15 and before the fluorinated hydrocarbon-based etching process. This surface fluorination process adheres fluorinated hydrocarbons to the surface of the alumina film, promoting the etching process performed by introducing hydrogen fluoride gas.

[0101] In this example, the plasma formation utilizing fluorocarbon gas is achieved by setting the CF4 gas introduction rate to 100 sccm and the pressure within the discharge chamber 305 to 50 Pa. Under these conditions, a plasma is formed using an induced magnetic field based on the high-frequency power of the antenna 302, and particles within the plasma are supplied to the surface of the wafer 14 through the through-hole 104 of the gas shower plate 103 for 15 seconds. Furthermore, as one cycle, a fluorination process based on fluorocarbon plasma and an etching process based on hydrogen fluoride (including the high-vacuum venting process between these processes) can be repeated at least once. Alternatively, before the etching process, after performing a fluorination process on an alumina film supplied with particles from the fluorocarbon gas plasma, a cyclic etching process can be performed, repeating multiple processes, including the etching process and the high-vacuum venting process before or after it, as one cycle at least once.

[0102] The fluorocarbon gas used in this example is not limited to CF4; it can be fluorocarbon gases such as C4F8 and C4F6, or hydrofluorocarbons such as CHF3 and CH2F2. Furthermore, it can also be a non-carbon gas such as NF3 and SF6. Additionally, the etching reaction can be accelerated by simultaneously passing fluorocarbons and hydrogen fluoride and then igniting the plasma.

[0103] Furthermore, if residue remains on the surface of the alumina after the etching process using hydrogen fluoride gas, a plasma removal process can be performed after the etching process and before the wafer 14 is removed from the upper surface of the stage 15. In this example, as conditions for forming the plasma for residue removal, the flow rates of nitrogen and hydrogen gas entering the discharge chamber 305 are set to 100 sccm, and the pressure inside the discharge chamber 305 is set to 50 Pa. The plasma particles formed in the discharge chamber 305 under these conditions are then supplied to the alumina film through the gas shower plate 103 for 15 seconds.

[0104] The process of removing the residue is performed as a process included in the above cycle. After the removal process, the etching process based on hydrogen fluoride gas is performed again after the process of high vacuum exhaust of the discharge chamber 305 or the processing chamber 5, and the cyclic etching process of these processes is repeated.

[0105] Example 3

[0106] use Figure 4 Another further embodiment of the present invention will be described. Figure 4 This is a schematic longitudinal cross-sectional view illustrating the structure of an etching processing apparatus according to another further embodiment of the present invention. In the etching processing apparatus 400 of this embodiment, in addition to the structure shown in Embodiment 2, it also includes a structure that uses the radiation of light irradiated from a lamp to promote the etching of alumina and the removal of surface residues.

[0107] In this example, regarding and Figure 2 Alternatively, the structure of the same reference numerals as shown in Figure 3 can be omitted unless necessary.

[0108] The difference between the etching apparatus 400 of this embodiment and the etching apparatus 300 of Embodiment 2 is as follows: the upper part of the top chamber 11” has a circular plate-shaped cover member with a dielectric window 401, which is permeable to quartz or the like, and is arranged in a ring around the central axis in the vertical direction of the cover member. Above the outside of the cover member and above the dielectric window 401, a lamp heater assembly 402, also arranged in a ring around the central axis, is arranged. The dielectric window 401 is installed on the cover member of the top chamber 11” with a seal such as an O-ring sandwiched between them. The deformation of the seal creates an airtight separation between the external space where the atmosphere is set to atmospheric pressure and the interior of the discharge chamber 305 inside the top chamber 11”. In addition to quartz, ceramic materials such as alumina, silicon carbide, and aluminum nitride can also be used to constitute the dielectric window 401.

[0109] A lamp heater assembly 402 is disposed above the dielectric window 401, and a DC power supply 403 is further electrically connected to the lamp heater assembly 402 to supply power to the lamp heater assembly 402. The lamp heater assembly 402 in this example uses a halogen lamp, but the heating effect of a lamp that uses infrared (sIR) light can also be achieved by using a lamp to heat the wafer 14.

[0110] On the cover member surrounding the opening of the circular through hole at the center of the cover member constituting the upper part of the bottom chamber 12, a top chamber 11” is mounted with O-rings or other sealing elements sandwiched between it. The diameter of the cylindrical space, i.e., the discharge chamber 305, located inside is set to be the same as or approximately the same as the opening of the through hole at the center of the cover member of the bottom chamber 12.

[0111] The gas jet plate 103 has a circular plate shape made of a light-transmitting material such as quartz, and is disposed inside the lower end of the through hole of the cover member of the bottom chamber 12 to form the top surface of the processing chamber 5. The diameter of the circular plate shape of the gas jet plate 103 is set to be the same as or greater than that of the wafer 14 placed on the stage 15 below, which can suppress the light radiated from the lamp heater assembly 402 above from being blocked in the path until it shines on the alumina film on the upper surface of the wafer 14, thereby reducing the amount of light.

[0112] Next, the etching process of the alumina film in this example will be described. In this embodiment, similar to Embodiment 2, the processing gas supplied to the space within the top chamber 11, i.e., the discharge chamber 305, is excited by an induced magnetic field generated by the high-frequency power supplied to the coil antenna 302, thereby generating plasma. The plasma particles are used to promote the etching of the alumina film or to remove surface residues. Further, in this embodiment, heating of the alumina film based on the radiation of light irradiated from the lamp heater assembly 402 onto the wafer 14 is used to accelerate the etching of the alumina film or to remove surface residues.

[0113] Similar to Embodiment 1, after the wafer 14 is transported to the processing chamber 4 within the bottom chamber 12, it is held on the stage 15. The control unit 35 detects whether the temperature of the stage 15 or the wafer 14 is set to a value within a suitable range for processing, including a given temperature such as -30°C. In this embodiment, the introduction of processing gas into the discharge chamber 305 or the formation of plasma is not performed until the temperature is detected to be within a suitable range for processing.

[0114] By irradiating the wafer 14 with light from the lamp heater assembly to raise its temperature, the etching reaction of the alumina film is accelerated compared to the etching process using only gas. With the wafer 14 held on the stage 15, and with hydrogen fluoride-containing gas supplied to the upper surface of the alumina film through the discharge chamber 305 and the through-hole 104 of the gas jet plate 103, the temperature of the wafer 14 and the alumina film is raised from below -25°C to a value of 200°C to 300°C by irradiation with light from the lamp heater assembly 402. Alternatively, after the temperature of the wafer 14 is raised to 200°C to 300°C by irradiation with light from the lamp heater assembly 402, hydrogen fluoride-containing gas can be supplied from the gas line 2 through the discharge chamber 305 and the gas jet plate 103 to the surface of the alumina film.

[0115] Furthermore, deposits may sometimes adhere to or be deposited on the sidewalls of the gas shower plate 103, the surface inside the through-hole 104, the surface of the wafer 14, or the surfaces generated in the discharge chamber 305 and the processing chamber 5. To remove such deposits, after an etching process in which processing gas is supplied to the surface of the alumina film for a given time, and before the start of subsequent processes such as a high-vacuum exhaust process to process the surface of the wafer 14, the wafer 14 can be heated by irradiating light with the lamp heater assembly 402 while gas is introduced into the vacuum or into the discharge chamber 5 to heat the surface of the alumina film. In this embodiment, the removal or cleaning process based on such heating of the wafer 14 or the interior of the chamber can be included in a single cycle as a whole of the multiple processes shown in Embodiments 1 and 2, performing a cycle etching process that repeats the cycle at least once. The removal or cleaning process can also be performed before or after the cycles of Embodiments 1 and 2.

[0116] In this example, the process of removing or cleaning based on the aforementioned heating uses a method based on... Figure 4 The process shown is the radiation of light by the lamp heater assembly 402 with a halogen lamp irradiating the surface of the wafer 14. The unit for heating the wafer 14 is not limited to the unit of this example that uses infrared light (IR light) contained in the halogen lamp. For example, it can also be a method of heating the wafer 14 by heating the stage 15 by supplying electricity to a linear or film heater disposed in the stage 15, or the wafer 14 can be transferred from the etching chamber 100 to another device for heating.

[0117] Furthermore, in the above embodiments, the etching process of the alumina film using a gas containing hydrogen fluoride is performed by maintaining the gap between the gas jet plate 103, which supplies the gas through the through-hole 104, and the upper surface of the alumina film or wafer 14 at less than 1 mm, and further maintaining the temperature of the alumina film or wafer 14 within the range of -50 to -20°C. On the other hand, in the high-vacuum degassing process, other oxidation, fluorination, residue removal, detachment, or cleaning processes, the gap or the temperature of the wafer 14 (or the stage 15 supporting it) is maintained at a size that allows these processes to be performed effectively or efficiently. For example, as described above, the stage 15 or gas jet plate 103 in this embodiment is configured to move in the vertical direction. Not only during the placement and disengagement of the stage 15 of the wafer 14, but also during the high vacuum exhaust process and the oxidation or fluorination process utilizing plasma particles formed in the discharge chamber 305, the stage 15 or gas jet plate 103 can be moved in response to the command signal from the control unit 35, and the size of the gap between them can be adjusted to an appropriate value.

[0118] Furthermore, in the process of removing or cleaning by heating based on light irradiating the surface of the wafer 14 from the aforementioned lamp heater assembly 402, the distance between the lamp heater assembly 402 and the wafer 14 can be adjusted to be appropriate for the process by moving the stage 15 in the vertical direction. Furthermore, in Figure 4 In the example, the lamp heater assembly 402 is positioned above the cover member, i.e., the top chamber 11', above the discharge chamber 305. However, the lamp heater assembly 402 can also be positioned around the outside of the top chamber 11' or the dielectric cylinder member 301, and a window member made of a light-transmitting material such as quartz can be used instead of the cover or top plate member of the bottom chamber 12 to airtightly seal the inside and outside of the bottom chamber 12. In this case, by having a structure that positions the stage 15 at a height that is sufficiently far from the window member in the vertical direction, the unevenness of the amount or intensity of light radiated from the lamp heater assembly 402 arranged in a ring around the gas shower plate 103 to the wafer 14 can be reduced.

[0119] Explanation of reference numerals in the attached figures

[0120] 1···Vacuum Chamber

[0121] 2. Gas pipelines

[0122] 3. Exhaust section

[0123] 4··· Processing Room

[0124] 5. Buffer room

[0125] 11, 11', 11”···Octopic chamber

[0126] 12···Basic Chamber

[0127] 14··· Chips

[0128] 15··· Platform

[0129] 16. Exhaust port

[0130] 17··· Cooler

[0131] 21··· Mass Flow Components

[0132] 31···Butterfly Valve

[0133] 32··· Mechanical booster pump

[0134] 200··· Etching Processing Equipment

[0135] 300··· Etching Processing Equipment

[0136] 301···Dielectric Cylinder Components

[0137] 302··· Coil Antenna

[0138] 303 Matching Component

[0139] 304 High-Frequency Power Supply

[0140] 305 Discharge Chamber

[0141] 400··· Etching Processing Unit

[0142] 401···Dielectric Window

[0143] 402···Lamp heater assembly

[0144] 403 DC Power Supply

Claims

1. An etching process, characterized in that, It has the following processes: A wafer with an alumina film on its upper surface is placed in a processing chamber and kept at a temperature below -20°C. Hydrogen fluoride vapor is supplied from multiple through holes in a plate-shaped member that covers the wafer above the upper surface of the wafer for a predetermined period of time. The condensed hydrogen fluoride enters the gap between the lower surface of the plate-shaped member and the upper surface of the wafer to etch the alumina film.

2. The etching method according to claim 1, wherein, The vapor of the mixture of hydrogen fluoride and alcohol is supplied to the gap.

3. The etching process according to claim 1 or 2, wherein, The alumina film is etched by maintaining the temperature of the wafer within the range of -50°C to -20°C.

4. The etching process according to claim 1 or 2, wherein, The alumina film is etched by maintaining the temperature of the wafer at -35°C.

5. The etching process according to claim 1 or 2, wherein, The size of the gap is less than 3mm.

6. The etching process method according to claim 1 or 2, wherein, The size of the gap is 1 mm.

7. The etching process according to claim 1 or 2, wherein, The distance between adjacent through holes of the plurality of through holes is set to a value in the range of 1 mm to 3 mm.

8. The etching process method according to claim 1 or 2, wherein, The distance between adjacent through holes is set to 2mm.

9. The etching process method according to claim 1 or 2, wherein, The diameter of the through hole is set to a value in the range of 1 mm to 3 mm.

10. The etching process method according to claim 1 or 2, wherein, The diameter of the through hole is set to 2mm.

11. The etching method according to claim 1 or 2, wherein, The process of etching the alumina film by introducing hydrogen fluoride vapor and venting the interior of the vacuum chamber to a lower pressure than that in the etching process are repeated multiple times as a whole cycle.

12. The etching process according to claim 1 or 2, wherein, The etching process includes the following steps: Before or after the process of etching the alumina film by introducing hydrogen fluoride vapor, particles formed in a plasma using fluorocarbon gases are supplied to the surface of the alumina film.

13. The etching process method according to claim 1 or 2, wherein, The etching process includes the following steps: Before or after the process of etching the alumina film by introducing hydrogen fluoride vapor, particles from a plasma formed by nitrogen or hydrogen are supplied to the alumina film.

14. The etching process according to claim 1 or 2, wherein, The process of etching the alumina film by introducing hydrogen fluoride vapor and heating the wafer to remove the product adhering to the alumina film is performed as a single cycle, and this cycle is repeated multiple times.

15. An etching process apparatus, characterized in that, have: Vacuum container; A stage is configured inside the vacuum container and a wafer of the object to be processed, on the upper surface, is placed thereon having an alumina film pre-prepared on its surface. The plate member, in the state of placing the wafer on the stage, is configured to cover the wafer by leaving a gap opposite to the alumina film of the wafer, and has a plurality of through holes for introducing vapor of a processing gas containing hydrogen fluoride into the wafer and introducing condensed hydrogen fluoride into the gap between the alumina film of the wafer and the lower surface of the plate member. as well as A temperature regulating mechanism adjusts the stage or the wafer on which it is placed to a temperature below -20°C.

16. The etching apparatus according to claim 15, wherein, The etching processing apparatus includes: The plate member has a plurality of through holes for introducing the vapors of the hydrogen fluoride and alcohol into the gap.

17. The etching apparatus according to claim 15 or 16, wherein, The etching processing apparatus includes: The temperature regulating mechanism adjusts the temperature of the stage or the wafer on which it is placed to a value within the range of -50°C to -20°C.

18. The etching apparatus according to claim 15 or 16, wherein, The etching processing apparatus includes: The temperature regulating mechanism adjusts the temperature of the stage or the wafer on which it is placed to -35°C.

19. The etching apparatus according to claim 15 or 16, wherein, The size of the gap is less than 3mm.

20. The etching apparatus according to claim 15 or 16, wherein, The size of the gap is less than 1 mm.

21. The etching apparatus according to claim 15 or 16, wherein, The distance between the plurality of through holes in the plate component is 1 mm to 3 mm.

22. The etching apparatus according to claim 15 or 16, wherein, The distance between the plurality of through holes in the plate component is 2 mm.

23. The etching apparatus according to claim 15 or 16, wherein, The diameter of the through hole is 1 mm to 3 mm.

24. The etching apparatus according to claim 15 or 16, wherein, The diameter of the through hole is 2mm.

25. The etching apparatus according to claim 15 or 16, wherein, The etching processing apparatus includes: A lamp that heats the wafer placed on the stage and is positioned above the stage to direct light onto the wafer; or Alternatively, a heater disposed within the stage can be used to heat the wafer placed on the stage.

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