Substrate processing method and substrate processing apparatus

Abstract

To provide a substrate processing method capable of oxidizing a molybdenum film in a method different from conventional methods and removing an oxidized portion of the molybdenum film from the substrate while leaving an unoxidized portion of the molybdenum film in the substrate, and a substrate processing device.SOLUTION: A substrate processing method includes a first oxidizing step S3, a first etching step S6, a second oxidizing step S4, and a second etching step S6. The first oxidizing step heats a substrate at a first temperature by irradiation of light of a first intensity while supplying an oxygen gas or an ozone gas to the substrate. The first etching step dissolves a surface layer of a molybdenum film that has changed to molybdenum trioxide in an etching liquid by supplying the etching liquid to the substrate. The second oxidizing step heats the substrate at a second temperature by irradiation of light of a second intensity while supplying an oxygen gas or an ozone gas to the substrate. The second etching step dissolves the surface layer of the molybdenum film that has changed to molybdenum trioxide in the etching liquid by supplying the etching liquid to the substrate.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a substrate processing method and a substrate processing apparatus for processing substrates, including, for example, semiconductor wafers, substrates for FPDs (Flat Panel Displays) such as liquid crystal displays and organic EL (electroluminescence) displays, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photomasks, ceramic substrates, and substrates for solar cells. [Background technology]

[0002] Patent Document 1 discloses that a molybdenum oxide portion is formed by oxidizing a molybdenum layer by oxygen ion implantation or oxygen plasma doping, and that the molybdenum oxide portion is removed from the substrate by wet etching, in which a liquid such as an ammonia solution is supplied to the substrate, while leaving a non-oxidized molybdenum layer on the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-509816 Summary of the Invention [Problem to be solved by the invention]

[0004] Although Patent Document 1 discloses oxidizing a molybdenum layer by oxygen ion implantation or oxygen plasma doping, it does not disclose oxidizing a molybdenum layer by methods other than these. If it is desired to oxidize a molybdenum layer by methods other than these, the disclosure of Patent Document 1 cannot meet such a demand.

[0005] An object of the present invention is to provide a substrate processing method and substrate processing apparatus that can oxidize a molybdenum film by a method different from conventional methods, and can remove the oxidized portion of the molybdenum film from the substrate while leaving the unoxidized portion of the molybdenum film on the substrate. [Means for solving the problem]

[0006] One embodiment of the present invention includes a first gas supply step of supplying oxygen gas or ozone gas to a substrate, and a first heating step of heating the substrate at a first temperature by irradiating the substrate with light of a first intensity, wherein the first gas supply step and the first heating step are performed simultaneously to change a surface layer of a molybdenum film formed on the substrate to molybdenum trioxide without changing the other portion of the molybdenum film to molybdenum trioxide; a first etching step of supplying an etching solution to the substrate to dissolve the surface layer, which has been changed to molybdenum trioxide in the first oxidation step, in the etching solution while leaving the other portion of the molybdenum film on the substrate; and a second gas supply step of supplying the oxygen gas or ozone gas to the substrate. a second heating step of heating the substrate at a second temperature higher or lower than the first temperature by irradiating the substrate with light of a second intensity stronger or weaker than the first intensity, and the second oxidation step of converting the surface layer of the molybdenum film to molybdenum trioxide without converting the other portion of the molybdenum film to molybdenum trioxide by simultaneously performing the second gas supply step and the second heating step before or after the first oxidation step and the first etching step; and a second etching step of supplying the etching solution to the substrate, thereby dissolving the surface layer converted to molybdenum trioxide in the second oxidation step into the etching solution while leaving the other portion of the molybdenum film on the substrate.

[0007] According to this method, the substrate is heated by irradiating it with light. Furthermore, oxygen gas or ozone gas is supplied to the substrate while irradiating the substrate with light. As a result, oxygen atoms contained in the oxygen gas or ozone gas bond with molybdenum, converting the surface layer of the molybdenum film to molybdenum trioxide. An etching solution is then supplied to the substrate. The molybdenum trioxide dissolves in the etching solution. Therefore, the surface layer of the molybdenum film that has converted to molybdenum trioxide is etched, and the remaining portion of the molybdenum film that has not converted to molybdenum trioxide remains on the substrate.

[0008] The thickness of the molybdenum oxide film formed by the conversion to molybdenum trioxide depends on the temperature of the substrate when oxygen gas or ozone gas is supplied. For example, increasing the substrate temperature increases the thickness of the molybdenum oxide film and decreases the thickness of the molybdenum film. When the surface layer of the molybdenum film is oxidized multiple times, heating the substrate at a high temperature each time increases the rate at which the molybdenum film thins, but makes it difficult to precisely control the thickness of the molybdenum film. On the other hand, heating the substrate at a low temperature each time makes it easier to precisely control the thickness of the molybdenum film, but decreases the rate at which the molybdenum film thins.

[0009] In this embodiment, when oxidizing the surface layer of the molybdenum film, the substrate temperature is changed by changing the intensity of light irradiated onto the substrate. Therefore, the thickness of the molybdenum film can be controlled more precisely than when the substrate is heated at a high temperature each time. In addition, the rate at which the molybdenum film thins can be increased compared to when the substrate is heated at a low temperature each time. This allows the molybdenum film to be thinned in a shorter time while maintaining its dimensional accuracy.

[0010] Oxygen gas and ozone gas are oxygen-atom-containing gases containing oxygen atoms. The oxygen-atom-containing gas may be supplied to the substrate by filling the oxidation space in which the substrate is placed with the oxygen-atom-containing gas, or by discharging the oxygen-atom-containing gas into the oxidation space. In the latter case, the oxidation space may be filled with the oxygen-atom-containing gas, or a gas other than the oxygen-atom-containing gas may be present in the oxidation space. In other words, the oxygen-atom-containing gas may be supplied to the substrate in any manner as long as a sufficient amount of oxygen atoms is supplied to the surface of the molybdenum film to convert molybdenum to molybdenum trioxide. The light (strictly speaking, electromagnetic waves) irradiated onto the substrate may be visible light (electromagnetic waves with a wavelength in the range of 380 to 800 nm) or invisible light (electromagnetic waves with a wavelength outside this range), or may include both visible light and invisible light.

[0011] In the above embodiment, at least one of the following features may be added to the substrate processing method.

[0012] At least one of the first heating step and the second heating step is a step of irradiating the substrate with light emitted from an LED (light emitting diode) lamp.

[0013] According to this method, the substrate is heated by irradiating it with light emitted from an LED lamp. Therefore, the temperature of the substrate can be increased more rapidly than when the substrate is heated with a hot plate, that is, when Joule heat is transferred to the substrate by thermal conduction. Furthermore, power consumption can be reduced compared to when the substrate is heated with other heat sources such as a hot plate or halogen lamp. In addition, the LED lamp has a long lifespan, so the frequency of component replacement can be reduced compared to when the substrate is heated with other heat lamps such as halogen lamps.

[0014] The substrate includes a silicon wafer and the molybdenum film held on the silicon wafer, and the wavelength of the light emitted from the LED lamp is within a range of 300 to 1000 nm.

[0015] According to this method, the LED lamp emits light with a wavelength in the range of 300 to 1000 nm. When the temperature of the silicon wafer is below 500°C and the wavelength of the light exceeds this range, the silicon wafer's light absorption rate is low. Therefore, high-intensity light must be irradiated onto the substrate to rapidly raise the substrate temperature. Increasing the light intensity increases power consumption and requires the use of larger heating lamps. Irradiating the substrate with light with a wavelength within this range increases the light absorption rate, allowing the substrate to be heated efficiently.

[0016] The first heating step includes a step of irradiating the substrate with light of the first intensity by causing a heat lamp to emit the light of the first intensity, and the substrate processing method further includes a step of causing the heat lamp to emit light of the second intensity.

[0017] According to this method, instead of having a second heat lamp, which is different from a first heat lamp that emits light of a first intensity, emit light of a second intensity, one heat lamp emits light of a first intensity and then emits light of a second intensity before or after that. In other words, by switching the intensity of light emitted from the heat lamp, the heat lamp emits light of the first intensity and light of the second intensity. Therefore, the number of heat lamps can be reduced compared to when different first and second heat lamps are provided.

[0018] The light of the second intensity emitted from the heat lamp may be irradiated onto the substrate that has been irradiated or is to be irradiated with the light of the first intensity emitted from the same heat lamp, or may be irradiated onto the substrate that has been irradiated or is to be irradiated with the light of the first intensity emitted from another heat lamp. In the former case, the second heating step includes a step of irradiating the substrate with the light of the second intensity by causing the heat lamp to emit the light of the second intensity.

[0019] The substrate processing method includes performing at least one of a first cycle including the first oxidation step and the first etching step and a second cycle including the second oxidation step and the second etching step multiple times.

[0020] According to this method, the substrate is heated while oxygen gas or ozone gas is supplied to the substrate, and then an etching solution is supplied to the substrate. Then, the substrate is heated again while oxygen gas or ozone gas is supplied to the substrate, and then an etching solution is supplied to the substrate. In other words, oxidation of the molybdenum film and etching of the molybdenum oxide film are alternately repeated multiple times. This allows the thickness of the molybdenum film to be reduced in stages, and the thickness of the molybdenum film to be adjusted in stages.

[0021] When a first cycle including the first oxidation step and the first etching step is performed multiple times, the amount of reduction in the thickness of the molybdenum film in the first etching step, i.e., the thickness of the molybdenum oxide film dissolved in the etching solution, may be the same each time or may vary among the multiple first etching steps. The same applies when a second cycle including the second oxidation step and the second etching step is performed multiple times.

[0022] When the first cycle is performed three or more times, the number of the second cycles performed between the first cycle and the next first cycle is different each time at a number of intervals equal to or less than the total number of intervals of the first cycle.

[0023] According to this method, a first cycle is performed three or more times, in which the substrate is heated to a first temperature by irradiating it with light of a first intensity while supplying oxygen gas or ozone gas to the substrate, and then an etching solution is supplied to the substrate.Furthermore, a second cycle is performed one or more times, in which the substrate is heated to a second temperature by irradiating it with light of a second intensity while supplying oxygen gas or ozone gas to the substrate, and then an etching solution is supplied to the substrate.

[0024] The number of second cycles performed between two first cycles varies each time at intervals equal to or less than the total number of intervals between the first cycles. For example, when three first cycles are performed, one second cycle is performed between the first and second first cycles, and two second cycles are performed between the second and third first cycles. When four first cycles are performed, one second cycle is performed between the first and second first cycles, and two second cycles are performed between the second and third first cycles. The number of second cycles performed between the third and fourth first cycles may be one or two, or may be zero or a value greater than or equal to three.

[0025] When the first cycle is performed individually on multiple substrates, if the first cycles are performed at the same time, the consumption of processing fluids such as processing gas and processing liquid, and the consumption of electricity may increase locally. By changing the number of second cycles performed between two first cycles, such local increases can be reduced, and the consumption of processing fluids and electricity per hour can be leveled out.

[0026] When the first cycle is performed three or more times, the number of second cycles performed between the first cycle and the next first cycle may be different among a plurality of substrates. Specifically, in processing a certain substrate, the number of second cycles performed between the first cycle and the next first cycle may be different for each of a plurality of intervals equal to or less than the total number of intervals between the first cycles, and in processing another substrate, the number of second cycles performed between the first cycle and the next first cycle may be the same for each of the substrates.

[0027] The first gas supplying step and the second gas supplying step are steps of supplying the ozone gas to the substrate.

[0028] According to this method, the substrate is heated while ozone gas, rather than oxygen gas, is supplied to the substrate. Therefore, the surface layer of the molybdenum film can be converted to molybdenum trioxide more efficiently than when the substrate is heated while oxygen gas is supplied to the substrate. This shortens the time required to convert the surface layer of the molybdenum film to molybdenum trioxide, and increases the throughput (number of substrates processed per unit time) of the substrate processing apparatus.

[0029] The etching solution is a water-containing solution containing water as a main component.

[0030] According to this method, a water-containing liquid containing water as a main component is supplied to a substrate to etch the substrate. While molybdenum trioxide dissolves in water, molybdenum is insoluble or barely soluble in water. Therefore, the surface layer of the molybdenum film that has been converted to molybdenum trioxide can be removed from the substrate without using a chemical solution. This simplifies the treatment of wastewater and reduces the environmental impact compared to when the etching solution is a chemical solution.

[0031] The water-containing liquid corresponding to the etching solution may be water such as pure water (a liquid with a water volume concentration of 100% or substantially 100%), or a liquid with a water volume concentration of 90% or more but less than 100%. In the latter case, a chemical may be dissolved in the water-containing liquid if the concentration is low. In this case, the surface layer of the molybdenum film that has been converted into molybdenum trioxide can be removed from the substrate in a shorter time.

[0032] In the substrate processing method, the first oxidation step, the first etching step, the second oxidation step, and the second etching step are performed in one substrate processing apparatus.

[0033] According to this method, the molybdenum film is oxidized and etched within a single substrate processing apparatus. In other words, after the substrate is loaded into the substrate processing apparatus through the load port, the substrate is not unloaded from the substrate processing apparatus through the load port until the oxidation of the molybdenum film and the etching of the molybdenum oxide film are completed. Therefore, the time required to transport the substrate can be shortened compared to when the oxidation of the molybdenum film and the etching of the molybdenum oxide film are performed in separate substrate processing apparatuses.

[0034] Another embodiment of the present invention is a first oxidizing means including a first gas supply port that supplies oxygen gas or ozone gas to a substrate, and a first heating lamp that heats the substrate at a first temperature by irradiating the substrate with light of a first intensity, and that converts a surface layer of a molybdenum film formed on the substrate into molybdenum trioxide without converting portions other than the surface layer of the molybdenum film into molybdenum trioxide by heating the substrate at the first temperature by irradiating the light of the first intensity while supplying the oxygen gas or ozone gas to the substrate; a first etching means for dissolving the surface layer of the molybdenum film, which has been converted to molybdenum trioxide by the first oxidation means, in the etching solution while leaving a portion other than the surface layer of the molybdenum film on the substrate by supplying the etching solution to the substrate; a second gas supply port, which may be the same as or different from the first gas supply port, for supplying the oxygen gas or ozone gas to the substrate; and a second gas supply port for irradiating the substrate with light of a second intensity, which may be stronger or weaker than the first intensity, thereby increasing the temperature to a temperature higher than the first temperature. a second heating lamp that is the same as or different from the first heating lamp and that heats the substrate at a second temperature that is higher or lower than the first temperature, and that heats the substrate at the second temperature by irradiating the substrate with light of the second intensity while supplying the oxygen gas or ozone gas to the substrate, thereby changing the surface layer of the molybdenum film to molybdenum trioxide without changing the other portions of the molybdenum film to molybdenum trioxide; a second etching means that is the same as or different from the first etching means and that includes a second etching solution nozzle that is the same as or different from the first etching solution nozzle and that supplies the etching solution to the substrate, and that, by supplying the etching solution to the substrate, dissolves the surface layer that has been changed to molybdenum trioxide by the second oxidation means in the etching solution while leaving the other portions of the molybdenum film on the substrate; and a transfer system that transfers the substrate between the first oxidation means, the first etching means, the second oxidation means, and the second etching means. This configuration can achieve the same effects as the above-described substrate processing method.At least one of the features relating to the substrate processing method described above may be added to the substrate processing apparatus. [Brief explanation of the drawings]

[0035] [Figure 1A] 1 is a schematic cross-sectional view showing an example of a cross section of a substrate before processing of the substrate according to an embodiment of the present invention is performed. [Figure 1B] 1 is a schematic cross-sectional view showing an example of a cross section of a substrate when processing of the substrate is being performed according to an embodiment of the present invention. [Figure 1C] 2 is a schematic cross-sectional view showing an example of a cross section of a substrate after processing of the substrate according to an embodiment of the present invention. FIG. [Figure 2] 1 is a schematic plan view showing a layout of a substrate processing apparatus according to an embodiment of the present invention. [Figure 3] FIG. 2 is a schematic cross-sectional view showing an example of a vertical cross section of an oxidation unit provided in the oxidation treatment unit. [Figure 4] FIG. 2 is a schematic cross-sectional view showing an example of a vertical cross section of an etching processing unit. [Figure 5] FIG. 2 is a block diagram showing an electrical configuration of the substrate processing apparatus. [Figure 6] 1 is a table showing an example of the number of high-temperature cycles and low-temperature cycles and the order of the high-temperature cycles and low-temperature cycles. [Figure 7A-B] 1 is a schematic cross-sectional view showing an example of a cross section of a substrate after a high-temperature oxidation step or a low-temperature oxidation step has been performed. [Figure 8] 10 is a graph showing the change in light intensity over time when a high-temperature oxidation process and a low-temperature oxidation process are performed. [Figure 9] 1 is a graph showing the change in substrate temperature over time when a high-temperature oxidation process and a low-temperature oxidation process are performed. [Figure 10] 1 is a flowchart illustrating an example of substrate processing according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0037] First, an outline of the processing of the substrate W according to one embodiment of the present invention will be described.

[0038] Fig. 1A is a schematic cross-sectional view showing an example of a cross section of a substrate W before processing of the substrate W according to an embodiment of the present invention. Fig. 1B is a schematic cross-sectional view showing an example of a cross section of the substrate W when processing of the substrate W according to an embodiment of the present invention is being performed. Fig. 1C is a schematic cross-sectional view showing an example of a cross section of the substrate W after processing of the substrate W according to an embodiment of the present invention.

[0039] The molybdenum film 100 is a thin film made of molybdenum formed on the surface of a substrate W such as a semiconductor wafer. The molybdenum film 100 may be part of metal wiring (molybdenum wiring) electrically connected to a device such as a transistor formed on the substrate W. The metal wiring may be a metal wiring layer disposed on an interlayer insulating film, or a metal plug disposed in a hole such as a via hole that penetrates at least one interlayer insulating film, or may be both a metal wiring layer and a metal plug.

[0040] 1A, the molybdenum film 100 is composed of a surface layer 102 that includes the entire surface 103 of the molybdenum film 100, and a bulk 101 that represents the portion of the molybdenum film 100 other than the surface layer 102. The surface layer 102 of the molybdenum film 100 represents a layer of a constant or approximately constant thickness from the surface 103 of the molybdenum film 100. Before the substrate W is processed, the surface 103 of the molybdenum film 100 may or may not be covered with a molybdenum oxide. Before the substrate W is processed, the surface 103 of the molybdenum film 100 or the surface of the molybdenum oxide may or may not be partially covered with another material, such as a resist pattern.

[0041] 1A shows an example in which the surface 103 of a molybdenum film 100 is covered with a native molybdenum oxide film 104 containing molybdenum oxide (MoO2) and molybdenum trioxide (MoO3). Both molybdenum oxide and molybdenum trioxide are examples of oxides of molybdenum. In the example shown in FIG. 1A, part or all of the surface 103 of the molybdenum film 100 is covered with the native molybdenum oxide film 104. The native molybdenum oxide film 104 is exposed on the surface of a substrate W, such as a semiconductor wafer, and is in contact with the atmosphere in the space in which the substrate W is placed.

[0042] In one embodiment of the present invention, a substrate W is processed by an oxidation process in which the substrate W is heated while an oxygen-atom-containing gas, such as ozone gas, is supplied to the substrate W. Ozone gas is an example of an oxygen-atom-containing gas that contains oxygen atoms. The oxygen-atom-containing gas may be oxygen gas. If a molybdenum oxide, such as a native oxide film 104, is formed on the molybdenum film 100, the molybdenum oxide may be removed from the molybdenum film 100 by wet etching or dry etching before the oxidation process, or the oxidation process may be performed without removing the molybdenum oxide.

[0043] When performing the oxidation step, the substrate W may be heated by contact heating or non-contact heating, or by both contact heating and non-contact heating. When heating the substrate W by contact heating, the substrate W may be placed horizontally on a hot plate that is hotter than room temperature (a constant or approximately constant temperature between 15 and 30°C) with the surface of the substrate W on which the device will be formed facing upward, so that the underside of the substrate W comes into contact with the hot plate. When heating the substrate W by non-contact heating, the substrate W may be irradiated with light emitted from a heat source such as a lamp. When performing the oxidation step, the substrate W may be in a horizontal or vertical position, or in another position.

[0044] During the oxidation step, the molybdenum in the molybdenum film 100 is oxidized by ozone or oxygen molecules in the atmosphere in contact with the substrate W, and the surface 103 of the molybdenum film 100 is converted to molybdenum trioxide. If the surface 103 of the molybdenum film 100 is covered with a molybdenum oxide such as a native oxide film 104, not only the surface 103 of the molybdenum film 100 but also the molybdenum oxide is converted to molybdenum trioxide. As a result, a molybdenum oxide film 105 containing molybdenum trioxide is formed on the surface 103 of the molybdenum film 100, as shown in FIG. 1B.

[0045] The molybdenum film 100 gradually changes to molybdenum trioxide from the surface 103 of the molybdenum film 100 toward the interior of the molybdenum film 100. The boundary between the molybdenum film 100 and the molybdenum oxide film 105 gradually moves toward the interior of the molybdenum film 100. This causes the thickness of the molybdenum oxide film 105 to continuously increase. When the time for performing the oxidation step reaches a maximum growth time, which will be described later, the molybdenum oxide film 105 having the maximum thickness, which will be described later, is formed on the surface 103 of the molybdenum film 100.

[0046] The molybdenum oxide film 105 is a thin film of molybdenum trioxide bonded to the molybdenum film 100. The molybdenum oxide film 105 may contain substances other than molybdenum trioxide, such as molybdenum oxide. FIG. 1B shows an example in which the entire surface 106 of the molybdenum oxide film 105 is flat and the thickness of the molybdenum oxide film 105 is uniform. The molybdenum oxide film 105 is thinner than the molybdenum film 100. The thickness of the molybdenum oxide film 105 may be equal to or greater than the thickness of the molybdenum film 100.

[0047] The time during which the oxidation process is performed (the time during which the substrate W is heated while being in contact with an oxygen atom-containing gas such as ozone gas) is defined as the oxidation time, and the conditions of the oxidation process excluding the oxidation time are defined as the oxidation conditions. The oxidation conditions include multiple parameters. For example, the temperature of the substrate W, the concentration of the ozone gas supplied to the substrate W, and the flow rate of the ozone gas supplied to the substrate W are included in the oxidation conditions. The oxidation time is not included in the oxidation conditions.

[0048] When the oxygen atom-containing gas is ozone gas, the oxidation conditions are as follows: Specifically, the temperature of the substrate W is 150° C. or higher, for example, in the range of 180 to 300° C. The concentration of the ozone gas is 50 g / m 3 or more, for example, 100 to 200 g / m 3 The flow rate of the ozone gas is 5 SLM (Standard Litter Min) or more, for example, in the range of 18 to 20 SLM. The oxidation time is 30 seconds or more, for example, in the range of 30 to 300 seconds. The etching time, which will be described later, is 30 seconds or more. The difference between the thickness of the molybdenum film 100 before the oxidation step and the thickness of the molybdenum film 100 after the etching step is defined as the recess depth. Depending on the oxidation conditions, the recess depth when the oxidation step and the etching step are performed once each is less than several tens of nanometers, for example, less than 10 nm. The above numerical values ​​are merely examples and are not limited to these.

[0049] If the oxidation conditions are constant, the thickness of the molybdenum oxide film 105 increases as the oxidation time increases. If the oxidation conditions are constant, even if the oxidation time exceeds the maximum growth time, the thickness of the molybdenum oxide film 105 remains unchanged or changes very little, remaining at or near the maximum thickness. In other words, if the oxidation conditions are constant, the thickness of the molybdenum oxide film 105 reaches its maximum thickness when the oxidation time reaches the maximum growth time. However, even if the oxidation process is continued for a longer time, the thickness of the molybdenum oxide film 105 remains unchanged or changes very little. This phenomenon is sometimes called self-limitation.

[0050] The maximum thickness of the molybdenum oxide film 105 depends on the oxidation conditions. The maximum growth time also depends on the oxidation conditions. When the oxidation conditions change, the maximum thickness of the molybdenum oxide film 105 increases or decreases accordingly. For example, when the temperature of the substrate W decreases, the maximum thickness of the molybdenum oxide film 105 decreases. When the concentration or flow rate of the ozone gas supplied to the substrate W decreases, the maximum thickness of the molybdenum oxide film 105 also decreases.

[0051] After the oxidation step, as shown in FIG. 1C, an etching step is performed in which an etching solution is supplied to the substrate W to remove the molybdenum oxide film 105 from the substrate W. FIG. 1C shows an example in which the molybdenum oxide film 105 is entirely removed by supplying the etching solution, exposing the flat surface 103 of the molybdenum film 100 formed of molybdenum. It is preferable that the molybdenum oxide film 105 is entirely removed from the substrate W by supplying the etching solution, but the molybdenum oxide film 105 may remain on the substrate W to the extent that it does not cause problems in subsequent steps.

[0052] An etching solution is a liquid that dissolves molybdenum trioxide but does not or barely dissolves molybdenum. Molybdenum trioxide dissolves in water, while molybdenum dissolves in water or barely dissolves in water. In other words, the rate at which molybdenum trioxide dissolves in water is greater than the rate at which molybdenum dissolves in water. Therefore, the etching solution may be any liquid containing water. For example, the etching solution may be water such as pure water (deionized water: DIW), or an aqueous solution such as ammonium hydroxide, an alkaline solution, carbonated water, hydrofluoric acid, or hydrochloric acid. The ratio of water to solute in the aqueous solution may be greater than or less than 100.

[0053] When the etching solution comes into contact with the surface 106 of the molybdenum oxide film 105, the molybdenum trioxide that constitutes the surface 106 of the molybdenum oxide film 105 dissolves in the etching solution, gradually reducing the molybdenum oxide film 105. When the etching time, i.e., the time the etching solution is in contact with the molybdenum oxide film 105, reaches the etching end time, all or almost all of the molybdenum oxide film 105 dissolves in the etching solution. The etching solution dissolves molybdenum trioxide but does not or barely dissolves molybdenum. Therefore, even if the supply of the etching solution is continued beyond the etching end time, the molybdenum film 100 does not or barely reduces.

[0054] When performing the etching process, the etching solution may be supplied to the substrate W continuously for at least the etching end time, or the etching solution may be supplied intermittently to the substrate W so that the cumulative etching time, which represents the total time that the etching solution is in contact with the molybdenum oxide film 105, is at least the etching end time. Furthermore, when performing the etching process, the orientation of the substrate W may be horizontal or vertical, or may be tilted relative to the horizontal plane. FIG. 1B shows an example in which the etching process is performed while the substrate W is maintained horizontal.

[0055] If an etching solution that corrodes molybdenum is supplied to the molybdenum film 100 after converting the surface layer 102 of the molybdenum film 100 into a molybdenum oxide film 105, rather than etching the molybdenum oxide film 105 with an etching solution, the roughness of the surface 103 of the molybdenum film 100 may not be satisfactory. As described above, if the surface layer 102 of the molybdenum film 100 is removed after converting it into a molybdenum oxide film 105, the roughness of the molybdenum film 100 after etching can be improved (reduced) compared to when the molybdenum film 100 is directly etched with an etching solution.

[0056] After all or almost all of the molybdenum oxide film 105 has been removed from the substrate W, a drying step is performed to dry the substrate W briefly or completely. That is, when a second or subsequent oxidation step is performed as described below, the substrate W may be simply dried so that most of the liquid is removed from the substrate W before the next oxidation step is performed, as long as the liquid remaining on the substrate W does not interfere with the oxidation step or the like. Alternatively, the substrate W may be completely dried so that all of the liquid is removed from the substrate W before the next oxidation step is performed. If the etching solution contains a high concentration of chemicals, the etching solution may be washed away with a rinse liquid such as pure water before drying the substrate W.

[0057] After the etching step, a second oxidation step is performed as described above, followed by a second etching step. If necessary, a third oxidation step and etching step may be performed, or a fourth or subsequent oxidation step and etching step may be performed. In other words, a cycle of performing the oxidation step and etching step in this order may be performed two or more times. In this way, the thickness of the molybdenum film 100 can be reduced stepwise. After the final etching step, the substrate W is completely dried.

[0058] As described above, in the oxidation process, the portion of the molybdenum film 100 on the surface 103 side is converted to molybdenum trioxide, and the thickness of the molybdenum film 100 is reduced, but the molybdenum film 100 is not etched. If the thickness of the molybdenum oxide film 105 formed in each oxidation process is constant or approximately constant, the etching amount is zero in the oxidation process, and the etching amount is constant or approximately constant, exceeding zero, in the etching process. This type of stepwise etching is also called digital etching.

[0059] Next, the substrate processing apparatus 1 will be described.

[0060] 2 is a schematic plan view showing the layout of a substrate processing apparatus 1 according to one embodiment of the present invention. The substrate processing apparatus 1 is an apparatus for processing disk-shaped substrates W such as semiconductor wafers. The substrate processing apparatus 1 includes a load port LP that supports carriers CA that accommodate a plurality of substrates W, a plurality of processing units 2 that process the substrates W transferred from the carriers CA on the load port LP with processing fluids such as processing liquids and processing gases, a transfer system 4 that transfers the substrates W between the carriers CA on the load port LP and the plurality of processing units 2, and a controller 3 that controls the substrate processing apparatus 1.

[0061] The multiple processing units 2 form multiple towers TW, each including one or more processing units 2. FIG. 2 shows an example in which four towers TW are formed. When multiple processing units 2 are included in one tower TW, the multiple processing units 2 are stacked one on top of the other. The number of processing units 2 included in one tower TW may be the same in all towers TW, or may be different in all or less than all of the multiple towers TW.

[0062] The multiple towers TW are arranged in two rows in the depth direction of the substrate processing apparatus 1 in a plan view (the left-right direction in FIG. 2; a direction perpendicular to the arrangement direction of the multiple load ports LP in a plan view). The two rows face each other across a linear transport path 5 that extends in the depth direction of the substrate processing apparatus 1 in a plan view. A center robot CR, which will be described later, is arranged on the transport path 5.

[0063] The processing units 2 include one or more oxidation processing units 2o that perform an oxidation process, and one or more etching processing units 2e that perform an etching process and a drying process. The oxidation processing unit 2o is a single-wafer processing unit that oxidizes the plurality of substrates W one by one. The etching processing unit 2e is a single-wafer processing unit that etches and dries the plurality of substrates W one by one.

[0064] 2 shows an example in which, in each of two rows, one tower TW closest to the load port LP is configured with an oxidation treatment unit 2o, and the remaining tower TW is configured with an etching treatment unit 2e. In this example, all treatment units 2 included in one tower TW are the same type of treatment unit 2 (oxidation treatment unit 2o or etching treatment unit 2e). The number and arrangement of towers TW configured with oxidation treatment units 2o are not limited to the example shown in FIG. 2. One tower TW may include both oxidation treatment units 2o and etching treatment units 2e.

[0065] The oxidation processing unit 2o includes a chamber 6 that forms an oxidation space SO (see Figure 3), a shutter 7 that opens and closes an entrance and exit provided in the chamber 6, an oxidation unit 10 that supplies processing gas to the substrate W while heating the substrate W within the chamber 6, a cooling unit 9 that cools the substrate W heated by the oxidation unit 10 within the chamber 6, and a local transport robot 8 that transports the substrate W within the chamber 6.

[0066] The local transfer robot 8 includes one or more hands 8h that support the substrate W horizontally. The hands 8h are movable parallel to both the horizontal and vertical directions. The local transfer robot 8 receives the substrate W from the center robot CR within the chamber 6, and delivers the substrate W to the center robot CR within the chamber 6. The local transfer robot 8 further delivers the substrate W to each of the oxidation unit 10 and the cooling unit 9, and receives the substrate W from each of the oxidation unit 10 and the cooling unit 9.

[0067] The etching processing unit 2e includes a chamber 41 that forms an etching space SE (see Figure 4), a shutter 42 that opens and closes an entrance and exit provided in the chamber 41, a spin chuck 43a that holds one substrate W horizontally within the etching space SE and rotates it around a vertical rotation axis A1 passing through the center of the substrate W, and multiple nozzles that eject processing liquid toward the substrate W held on the spin chuck 43a.

[0068] The transport system 4 includes a shuttle robot SH on which substrates W are temporarily placed to be transported between a carrier CA on the load port LP and a plurality of processing units 2, an indexer robot IR that transports substrates W between the carrier CA on the load port LP and the shuttle robot SH, and a center robot CR that transports substrates W between the shuttle robot SH and a plurality of processing units 2.

[0069] The shuttle robot SH is disposed between the indexer robot IR and the center robot CR in a plan view. The shuttle robot SH supports one or more substrates W horizontally and transports them between the indexer robot IR and the center robot CR. The indexer robot IR and the center robot CR load and unload substrates W into and from the shuttle robot SH. Substrates W are transferred between the indexer robot IR and the center robot CR via the shuttle robot SH. Substrates W may also be transferred directly between the indexer robot IR and the center robot CR without going through the shuttle robot SH.

[0070] The indexer robot IR is disposed between the shuttle robot SH and the load port LP in a plan view. The indexer robot IR includes one or more hands Hi that support a substrate W horizontally. The hands Hi can move parallel to both the horizontal and vertical directions. The hands Hi can rotate 180 degrees or more around a vertical line. The hands Hi can load and unload a substrate W onto and from a carrier CA on any of the load ports LP, and can load and unload a substrate W onto and from the shuttle robot SH.

[0071] The center robot CR is disposed in a transport path 5 that extends from the shuttle robot SH in the depth direction of the substrate W in a plan view. The center robot CR includes one or more hands Hc that support the substrate W horizontally. The hands Hc can move parallel to both the horizontal and vertical directions. The hands Hc can rotate 180 degrees or more around a vertical line. The hands Hc can load and unload the substrate W into and from the shuttle robot SH, and can load and unload the substrate W into and from any of the processing units 2.

[0072] The planar and three-dimensional arrangement of the multiple processing units 2 is not limited to the example shown in Fig. 2. In other words, the multiple processing units 2 may be arranged in any manner as long as the center robot CR can load and unload the substrate W into and from any of the processing units 2. The number of center robots CR provided in the substrate processing apparatus 1 may be two or more. In this case, as long as at least one center robot CR can load and unload the substrate W into and from each processing unit 2, it is not necessary for one center robot CR to load and unload the substrate W into and from all of the processing units 2.

[0073] 1A, a carrier CA containing a plurality of substrates W with an exposed molybdenum film 100 or a molybdenum native oxide film 104 is placed on a load port LP by a carrier transport robot installed in a manufacturing factory for manufacturing semiconductor devices, FPDs, etc. The carrier CA is a container that holds and contains the plurality of substrates W in a horizontal position so that the substrates W face each other in parallel with a gap between them. The carrier CA may be a FOUP (Front-Opening Unified Pod) or a container other than a FOUP.

[0074] An unprocessed substrate W is unloaded from a carrier CA on a load port LP by an indexer robot IR and loaded into an oxidation processing unit 2o by a center robot CR. The oxidation unit 10 of the oxidation processing unit 2o performs an oxidation process on the loaded substrate W. The substrate W that has undergone the oxidation process is unloaded from the oxidation processing unit 2o by the center robot CR and loaded into an etching processing unit 2e by the center robot CR. Before unloading the substrate W that has undergone the oxidation process from the oxidation processing unit 2o, the substrate W may be cooled in a cooling unit 9 of the oxidation processing unit 2o, if necessary.

[0075] The etching processing unit 2e performs an etching process and a drying process on the substrate W that has been carried in. Thereafter, the substrate W is unloaded from the etching processing unit 2e by the center robot CR and loaded into the same or a different oxidation processing unit 2o as the previous one. After the second oxidation process has been performed, the substrate W is unloaded from the oxidation processing unit 2o by the center robot CR and loaded into the same or a different etching processing unit 2e as the previous one.

[0076] In this way, one cycle including the oxidation step, etching step, and drying step is performed multiple times on one substrate W. After all the processes have been completed, the substrate W is loaded into a carrier CA on the same or another load port LP by the indexer robot IR. Thereafter, the carrier CA containing the processed substrates W is transported from the load port LP to its next destination by the carrier transport robot.

[0077] Next, the oxidation treatment unit 2o will be described in detail.

[0078] 3 is a schematic cross-sectional view showing an example of a vertical cross-section of an oxidation unit 10 provided in the oxidation processing unit 2o. The oxidation unit 10 includes a chamber 21 that accommodates a substrate W. The chamber 21 includes a fixed container 24 disposed below the substrate W and a movable lid 23 disposed above the substrate W. The movable lid 23 is movable up and down between an open position where the substrate W can enter and exit the space between the movable lid 23 and the fixed container 24, and a closed position (position shown in FIG. 3) where the space between the movable lid 23 and the fixed container 24 is sealed.

[0079] The opening / closing actuator 22 moves the movable lid 23 up and down between an open position and a closed position. When the opening / closing actuator 22 moves the movable lid 23 to the closed position, the annular portion 23a of the movable lid 23 overlaps the entire circumference of the annular portion 24a of the fixed container 24 via a seal outside the oxidation space SO, sealing the gap between the annular portions 23a and 24a. This forms a sealed oxidation space SO between the movable lid 23 and the fixed container 24.

[0080] The opening / closing actuator 22 is an actuator that moves the movable lid 23. An actuator is a device that converts electrical, fluid, magnetic, thermal, or chemical energy into mechanical work. Actuators include electric motors, air cylinders, and other devices. The opening / closing actuator 22 may be an electric motor or an air cylinder, or may be something other than these. The definition of actuator is similar for other actuators.

[0081] The oxidation unit 10 includes a susceptor 25 that horizontally supports the substrate W within the chamber 21. The susceptor 25 includes a plurality of support pins 26 that contact the underside of the substrate W to horizontally support the substrate W, and a partition 27 that supports the plurality of support pins 26. The support pins 26 and the partition 27 are arranged between the movable lid 23 and the fixed container 24 in the vertical direction. The partition 27 may be a single plate, or may be a plurality of plates arranged on a single plane and connected to each other.

[0082] The plurality of support pins 26 protrude upward from the upper surface of the partition 27. The hand 8h (see FIG. 2) of the local transport robot 8 places the substrate W on the plurality of support pins 26 and picks up the substrate W from the plurality of support pins 26. When the substrate W is placed on the plurality of support pins 26, the lower surface of the substrate W faces the upper surface of the partition 27 in parallel, with the lower surface of the substrate W spaced above the upper surface of the partition 27.

[0083] The support pins 26 may be integral with or fixed to the partition 27, or may be movable up and down relative to the partition 27. In the former case, the height of the support pins 26, i.e., the vertical distance from the upper surface of the partition 27 to the upper ends of the support pins 26, may be set so that the hand 8h can be positioned between the support position where the substrate W supported by the multiple support pins 26 is positioned and the upper surface of the partition 27. In the latter case, the hand 8h may place the substrate W on the multiple support pins 26 and move the multiple support pins 26 up and down between an upper position where the hand 8h places the substrate W on the multiple support pins 26 and picks up the substrate W from the multiple support pins 26, and a lower position below the upper position. The height of the multiple support pins 26 when positioned at the lower position may be less than the height in the former case.

[0084] The partition 27 is disposed within the fixed container 24. The partition 27 divides the internal space of the chamber 21 into an upper space above the partition 27 and a lower space below the partition 27. The upper space is the space from the top surface of the partition 27 to the ceiling surface of the movable lid 23. The lower space is the space from the bottom surface of the fixed container 24 to the bottom surface of the partition 27. The upper space corresponds to the oxidation space SO. When the movable lid 23 is placed in the closed position, the upper space corresponding to the oxidation space SO is sealed. The gap between the inner circumferential surface of the fixed container 24 and the outer circumferential surface of the partition 27 is sealed, and fluid in the upper space cannot move to the lower space. The lower space may be a sealed space or an open space through which fluid can freely flow.

[0085] The oxidation unit 10 includes at least one heat lamp 28 that irradiates light onto the substrate W supported on the susceptor 25 in the oxidation space SO, thereby heating the substrate W to a heating temperature. The heat lamp 28 is an example of a heater that heats the substrate W in the oxidation space SO. The heat lamp 28 includes a light source that emits light when supplied with power and a transparent case that houses the light source. The heat lamp 28 may be a halogen lamp or an LED (light emitting diode) lamp, or may be another type of lamp.

[0086] 3 shows an example in which four heat lamps 28 are arranged inside the chamber 21, and each heat lamp 28 is an LED lamp. In this example, the four heat lamps 28 are arranged below the substrate W. The number of heat lamps 28 that irradiate light toward the substrate W inside one chamber 21 may be less than four or five or more. The heat lamps 28 may also be arranged outside the chamber 21 as long as they can irradiate light onto the substrate W inside the chamber 21. All or some of the heat lamps 28 may also be arranged above the substrate W.

[0087] In the example shown in FIG. 3, four heat lamps 28 are arranged below the partition 27. Light from the heat lamps 28 passes through the partition 27 and is irradiated onto the substrates W on the multiple support pins 26. At least a portion of the partition 27 is made of a material that transmits the light from the heat lamps 28. For example, the entire susceptor 25 may be made of quartz. As long as the substrates W on the multiple support pins 26 can be uniformly heated by the light from all of the heat lamps 28, the entire partition 27 does not need to be made of a material that transmits the light from the heat lamps 28.

[0088] The substrate W irradiated with light from the LED lamp includes a disk-shaped silicon wafer 107, which is an example of a semiconductor wafer, and a molybdenum film 100 held on the silicon wafer 107. The LED lamp emits light with wavelengths within the range of 300 to 1000 nm. That is, light with wavelengths within this range is included in the light emitted from the LED lamp. The wavelength of the light with the highest intensity among the light emitted from the LED lamp may be within this range, or it may be outside this range. All of the wavelengths of the light emitted from the LED lamp may be within this range, or only a portion of the wavelengths of the light emitted from the LED lamp may be within this range. All of the wavelengths of the light emitted from the LED lamp may be outside this range.

[0089] Oxidation unit 10 includes intensity control circuit 29, which controls the intensity of light emitted from heat lamp 28 by controlling the current supplied to heat lamp 28. Intensity control circuit 29 is an electric circuit that increases or decreases the intensity of light emitted from heat lamp 28 by increasing or decreasing the current supplied to heat lamp 28, and stabilizes the intensity of light emitted from heat lamp 28 by stabilizing the current supplied to heat lamp 28.

[0090] The intensity control circuit 29 causes the heat lamps 28 to emit light at any intensity within a range from the minimum intensity to the maximum intensity. Changing the intensity of the light emitted from the heat lamps 28 changes the irradiance of the light irradiated on the substrate W, and the temperature of the substrate W also changes. Therefore, the intensity control circuit 29 can maintain the substrate W at any temperature within a range from a minimum temperature corresponding to the minimum intensity to a maximum temperature corresponding to the maximum intensity. The minimum temperature is 150°C, and the maximum temperature is 300°C. These values ​​are merely examples and are not limiting. For example, the maximum temperature may be 500°C.

[0091] The oxidation unit 10 may be provided with a radiation thermometer 30 that measures the temperature of the substrate W supported by the susceptor 25 in a non-contact manner. FIG. 3 shows an example in which three radiation thermometers 30 are held by the movable lid 23 and arranged above the substrate W. When the substrate W is irradiated with light from the heat lamps 28, feedback control may be performed in which the intensity of the light is changed by the intensity control circuit 29 based on the detection value of the radiation thermometer 30. In this way, overshoot and undershoot of the actual temperature of the substrate W can be reduced.

[0092] The oxidation unit 10 includes a gas supply port 31a that supplies ozone gas to the substrate W in the oxidation space SO. The gas supply port 31a includes a space through which the ozone gas passes and an end face that defines this space (typically, an annular end face that surrounds the entire periphery of the space). As long as the ozone gas flowing out from the gas supply port 31a is supplied to the oxidation space SO, the gas supply port 31a may open on a wall surface that defines the oxidation space SO, or may be located inside the wall surface. Figure 3 shows an example of the former.

[0093] In addition to the gas supply port 31a, the oxidation unit 10 includes an ozone gas generator 31d that generates ozone gas to be supplied to the gas supply port 31a, an ozone gas pipe 31b that guides the ozone gas generated by the ozone gas generator 31d toward the gas supply port 31a, and an ozone gas valve 31c that opens and closes between an open state in which ozone gas flows from the ozone gas pipe 31b to the gas supply port 31a and a closed state in which ozone gas does not flow from the ozone gas pipe 31b to the gas supply port 31a.

[0094] Although not shown, the ozone gas valve 31c includes a valve body having an internal flow path through which a fluid flows and an annular valve seat that forms part of the internal flow path, a valve element that is movable relative to the valve seat, and an actuator that moves the valve element between a closed position in which the valve element contacts the valve seat and an open position in which the valve element is spaced from the valve seat. The same applies to the other valves. The actuator may be a pneumatic actuator, an electric actuator, or another type of actuator. The control device 3 (see FIG. 2) controls the actuator to open and close the ozone gas valve 31c.

[0095] The oxidation unit 10 further includes an exhaust port 33a for exhausting gas from the oxidation space SO, an exhaust pipe 33b for directing the gas that has flowed into the exhaust port 33a away from the oxidation space SO, and an exhaust valve 33c that opens and closes between an open state in which the gas from the oxidation space SO flows into the exhaust port 33a and a closed state in which the gas from the oxidation space SO does not flow into the exhaust port 33a. The exhaust port 33a includes a space through which the gas to be exhausted passes and an end surface that defines this space. As long as the exhaust port 33a can exhaust the gas from the oxidation space SO, the exhaust port 33a may open in a wall surface that defines the oxidation space SO or may be located inside the wall surface.

[0096] When the ozone gas valve 31c is opened, ozone gas flows out from the gas supply port 31a and is supplied to the oxidation space SO. If the supply of ozone gas continues with the exhaust valve 33c open, the oxidation space SO is filled with ozone gas. Filling of the oxidation space SO with ozone gas can be achieved by supplying ozone gas to the oxidation space SO while exhausting the gas in the oxidation space SO through the exhaust port 33a, or by supplying ozone gas to the oxidation space SO after exhausting the gas in the oxidation space SO through the exhaust port 33a.

[0097] After the oxidation space SO is filled with ozone gas, the supply of ozone gas from the gas supply port 31a and the discharge of gas to the exhaust port 33a may be continued or stopped. In the former case, the pressure inside the oxidation space SO may be maintained at a value equal to or lower than the pressure outside the oxidation space SO while the oxidation space SO is filled with ozone gas. In this case, the exhaust valve 33c may be a relief valve that, when the pressure in the oxidation space SO rises above a set value, allows the gas inside the oxidation space SO to flow into the exhaust port 33a until the pressure drops below the set value. The exhaust valve 33c may include both an opening / closing valve and a relief valve.

[0098] The oxidation unit 10 includes an inert gas pipe 32a that introduces nitrogen gas, an example of an inert gas to be supplied to the oxidation space SO, and an inert gas valve 32b that opens and closes between an open state in which nitrogen gas flows from the inert gas pipe 32a to the oxidation space SO and a closed state in which nitrogen gas does not flow from the inert gas pipe 32a to the oxidation space SO. Fig. 3 shows an example in which nitrogen gas in the inert gas pipe 32a is supplied to the oxidation space SO via a gas supply port 31a. The nitrogen gas in the inert gas pipe 32a may also be supplied to the oxidation space SO via a gas supply port other than the gas supply port 31a.

[0099] After ozone gas is supplied to the oxidation space SO, the ozone gas in the oxidation space SO is exhausted through the exhaust port 33a. Specifically, after ozone gas is supplied to the oxidation space SO, the ozone gas valve 31c is closed, the exhaust valve 33c is opened, and the inert gas valve 32b is opened. As a result, nitrogen gas is supplied to the oxidation space SO, and gases in the oxidation space SO, such as ozone gas, are exhausted through the exhaust port 33a. As a result, the ozone gas in the oxidation space SO is replaced with nitrogen gas, and the oxidation space SO is filled with nitrogen gas.

[0100] An example of the treatment of the substrate W performed in the oxidation unit 10 is as follows.

[0101] Specifically, when processing the substrate W in the oxidation unit 10, with the movable lid 23 placed in the open position, the local transport robot 8 moves the hand 8h above the fixed container 24 while supporting the substrate W horizontally with the hand 8h. Thereafter, the local transport robot 8 places the substrate W on the hand 8h on the susceptor 25 and moves the hand 8h out of the chamber 21. Thereafter, the opening / closing actuator 22 moves the movable lid 23 to the closed position, sealing the space between the movable lid 23 and the fixed container 24.

[0102] After the movable lid 23 is placed in the closed position, as described above, ozone gas is filled into the oxidation space SO and supplied to the substrate W in the oxidation space SO. Before or after the oxidation space SO is filled with ozone gas, the heat lamps 28 are caused to start emitting light. This causes the heat lamps 28 to emit light of an intensity corresponding to the set temperature, and the substrate W is heated to the set temperature by the light irradiation. Thereafter, the oxidation process is carried out continuously for at least the maximum growth time described above while maintaining constant conditions such as the temperature of the substrate W and the concentration of ozone gas in the atmosphere in contact with the substrate W.

[0103] During the oxidation process, oxygen atoms in the atmosphere in contact with the substrate W bond with the molybdenum in the molybdenum film 100 (see FIG. 1B), converting the molybdenum to molybdenum trioxide. The oxygen atoms diffuse within the molybdenum film 100. As a result, a molybdenum oxide film 105 (see FIG. 1B) containing molybdenum trioxide is formed on the surface 103 of the molybdenum film 100. Furthermore, if the oxidation process is continued for a maximum growth time or longer while maintaining constant oxidation conditions, the thickness of the molybdenum oxide film 105 increases to and remains at the maximum thickness due to the self-limitation described above.

[0104] After the oxidation step is completed, the heat lamps 28 stop emitting light. Before or after the heat lamps 28 stop emitting light, gases such as ozone gas in the oxidation space SO are exhausted through the exhaust port 33a, and the oxidation space SO is filled with gases other than ozone gas, such as an inert gas. After the heat lamps 28 stop emitting light and the ozone gas in the oxidation space SO is exhausted, the local transfer robot 8 moves the hand 8h above the fixed container 24 with the movable lid 23 in the open position. Thereafter, the local transfer robot 8 picks up the substrate W on the susceptor 25 with the hand 8h and moves the hand 8h out of the chamber 21.

[0105] In this way, ozone gas is supplied to the sealed oxidation space SO. The heat lamps 28 are separated from the oxidation space SO by the partitions 27. Gas in the oxidation space SO cannot move into the space below where the heat lamps 28 are located. This prevents the heat lamps 28 from being exposed to ozone gas. Furthermore, because the substrate W is supported by point or line contact with the support pins 26, the contact area between the substrate W and the susceptor 25 can be reduced, and the amount of heat diffusing from the substrate W to the susceptor 25 can be reduced. This allows the substrate W to be efficiently heated by the light from the heat lamps 28.

[0106] When the substrate W is heated with light from an LED lamp, which is an example of the heating lamp 28, thermal energy can be concentrated on the substrate W compared to when the substrate W is heated with a hot plate, and the activity of oxygen atoms in and around the substrate W can be increased more efficiently. Furthermore, when the LED lamp starts to emit light, the temperature of the substrate W rises rapidly, and when the LED lamp stops emitting light, the temperature of the substrate W drops rapidly. Because the temperature of the substrate W drops rapidly when the LED lamp stops emitting light, cooling of the substrate W can be omitted or the cooling time of the substrate W can be shortened.

[0107] In contrast, when heating the substrate W with a hot plate, the hot plate must be preheated, and the temperature of the hot plate cannot be lowered even after the maximum growth time has elapsed in order to stabilize the temperature of the hot plate. Therefore, power consumption can be significantly reduced compared to when heating the substrate W with a hot plate. Furthermore, compared to when heating the substrate W with a hot plate, the amount of heat transferred to components other than the substrate W can be reduced, and corrosion of those components due to heating can be prevented or delayed.

[0108] Next, the etching processing unit 2e will be described.

[0109] 4 is a schematic cross-sectional view showing an example of a vertical cross section of the etching processing unit 2e. The etching processing unit 2e includes a chamber 41 forming an etching space SE, a shutter 42 for opening and closing an entrance provided in the chamber 41, and a spin chuck 43a for holding one substrate W horizontally in the etching space SE and rotating the substrate W about a vertical rotation axis A1 passing through the center of the substrate W.

[0110] The spin chuck 43a may be a clamping chuck that brings multiple chuck pins 43b into contact with the outer peripheral surface of the substrate W, or a vacuum chuck that holds the substrate W horizontally by adsorbing the back surface (lower surface) of the substrate W, which is the surface on which devices are not formed, to the upper surface of the spin base 43c. Fig. 4 shows an example of the former. The spin chuck 43a includes an electric motor 43d that rotates the substrate W held by the spin chuck 43a in a horizontal position about a rotation axis A1.

[0111] The etching processing unit 2e includes an etching liquid nozzle 44a that supplies an etching liquid to the upper surface of the substrate W held on the spin chuck 43a, and a rinse liquid nozzle 45a that supplies a rinse liquid to the upper surface of the substrate W held on the spin chuck 43a. FIG. 4 shows an example in which both the etching liquid and the rinse liquid are pure water (denoted as DIW in FIG. 4). The rinse liquid is not limited to pure water, and may be any of IPA (isopropyl alcohol), carbonated water, electrolytic ionized water, hydrogen water, ozone water, diluted hydrochloric acid water (e.g., about 10 to 100 ppm), and diluted ammonium hydroxide (e.g., about 10 to 100 ppm). The rinse liquid may be a different type of liquid from the etching liquid.

[0112] 4, the etching processing unit 2e includes an etching solution pipe 44b that introduces the etching solution to the etching solution nozzle 44a, and an etching solution valve 44c that opens and closes between an open state in which the etching solution flows from the etching solution pipe 44b to the etching solution nozzle 44a and a closed state in which the etching solution does not flow from the etching solution pipe 44b to the etching solution nozzle 44a. When the etching solution valve 44c is opened, the etching solution is continuously discharged downward from the discharge port of the etching solution nozzle 44a.

[0113] The etching processing unit 2e includes a rinse liquid pipe 45b that introduces the rinse liquid toward the rinse liquid nozzle 45a, and a rinse liquid valve 45c that opens and closes between an open state in which the rinse liquid flows from the rinse liquid pipe 45b to the rinse liquid nozzle 45a and a closed state in which the rinse liquid does not flow from the rinse liquid pipe 45b to the rinse liquid nozzle 45a. When the rinse liquid valve 45c is open, the rinse liquid is continuously discharged downward from the discharge port of the rinse liquid nozzle 45a.

[0114] The etching liquid nozzle 44a may be a scan nozzle that can move the collision position of the processing liquid on the substrate W within the upper or lower surface of the substrate W, or may be a fixed nozzle that cannot move the collision position of the processing liquid on the substrate W. The same applies to the rinse liquid nozzle 45a. Figure 4 shows an example in which the etching liquid nozzle 44a is a scan nozzle and the rinse liquid nozzle 45a is a fixed nozzle.

[0115] The etching liquid nozzle 44a is connected to a nozzle actuator 44e that moves the etching liquid nozzle 44a in at least one of the vertical and horizontal directions. The etching liquid nozzle 44a extends downward from the tip of a horizontally extending nozzle arm 44d. The nozzle actuator 44e is connected to the etching liquid nozzle 44a via the nozzle arm 44d. By moving the nozzle arm 44d, the nozzle actuator 44e horizontally moves the etching liquid nozzle 44a between a processing position (position shown in FIG. 4) where the etching liquid discharged from the etching liquid nozzle 44a is supplied to the upper surface of the substrate W and a standby position where the etching liquid nozzle 44a is positioned around the spin chuck 43a in a plan view.

[0116] The etching processing unit 2e includes a cylindrical processing cup 46 that receives liquid splashed from the substrate W held on the spin chuck 43a or from the spin chuck 43a. The processing cup 46 includes a plurality of guards 47 that receive liquid splashed outward from the substrate W or the spin chuck 43a, and a plurality of cups 48 that receive liquid guided downward by the plurality of guards 47. Figure 2 shows an example in which two guards 47 and two cups 48 are provided, and one cup 48 is integrated with one guard 47.

[0117] The etching processing unit 2e includes a guard lifting unit 49 that individually lifts and lowers the multiple guards 47. The guard lifting unit 49 positions the guards 47 at any position between the upper position and the lower position. The upper position is a position where the upper end of the guard 47 is positioned higher than the holding position where the substrate W held by the spin chuck 43a is positioned. The lower position is a position where the upper end of the guard 47 is positioned lower than the holding position. The upper end of the guard 47 surrounds the substrate W and the spin base 43c in a plan view.

[0118] When a processing liquid is supplied to the substrate W while the spin chuck 43a is rotating the substrate W, the processing liquid supplied to the substrate W is shaken off from the substrate W. When the processing liquid is supplied to the substrate W, the upper end of at least one guard 47 is positioned above the substrate W. Therefore, the processing liquid, such as a chemical liquid or a rinse liquid, discharged from the substrate W is received by one of the guards 47 and guided to the cup 48 corresponding to this guard 47.

[0119] An example of the processing of the substrate W performed in the etching processing unit 2e is as follows.

[0120] Specifically, with the entrance of the etching processing unit 2e open, the center robot CR (see FIG. 2) supports the substrate W horizontally with the hand Hc and moves the hand Hc above the spin chuck 43a. After placing the substrate W on the spin chuck 43a, the center robot CR moves the hand Hc out of the etching processing unit 2e through the entrance. The entrance is then closed by the shutter 42. Once the substrate W is placed on the spin chuck 43a, the spin chuck 43a holds the substrate W with multiple chuck pins 43b and rotates the substrate W with the electric motor 43d. The guard lifting unit 49 lifts at least one guard 47 from a lower position to an upper position.

[0121] After the substrate W is held by the spin chuck 43a, an etching step is performed in which an etching liquid is supplied to the substrate W. Specifically, while the spin chuck 43a is rotating the substrate W, the etching liquid valve 44c is opened and the etching liquid nozzle 44a begins to discharge the etching liquid. This causes the etching liquid to be supplied to the entire upper surface of the substrate W. After the entire upper surface of the substrate W is covered with a liquid film of the etching liquid, the supply of new etching liquid to the substrate W may be stopped, and a puddle step may be performed in which the entire upper surface of the substrate W is maintained in a state where the liquid film of the etching liquid is covered while the substrate W is stationary or rotated at a low speed (for example, 30 rpm or less).

[0122] When the etching liquid has been supplied to the substrate W for at least the aforementioned etching end time, the etching liquid valve 44c is closed. Then, a rinsing step is performed in which a rinse liquid is supplied to the substrate W. Specifically, while the spin chuck 43a is rotating the substrate W and the entire upper surface of the substrate W is covered with a liquid film of the etching liquid, the rinse liquid valve 45c is opened and the rinse liquid nozzle 45a begins to discharge the rinse liquid. As a result, the rinse liquid is supplied to the entire upper surface of the substrate W, washing away the etching liquid on the substrate W.

[0123] When a predetermined time has elapsed since the supply of the rinse liquid began, the rinse liquid valve 45c is closed. Thereafter, a drying process is performed in which the substrate W is dried by rotating the substrate W at high speed. Specifically, with the discharge of the rinse liquid from the rinse liquid nozzle 45a stopped, the electric motor 43d accelerates the substrate W in the rotation direction, and rotates the substrate W at a high rotation speed (for example, several thousand rpm) that is higher than the rotation speed of the substrate W from the etching process to the rinsing process. This removes the liquid from the substrate W, and the substrate W is dried. When a predetermined time has elapsed since the high-speed rotation of the substrate W began, the electric motor 43d stops rotating.

[0124] After the rotation of the substrate W has stopped, all guards 47 are placed in the lower position. In this state, the entrance is opened, and the center robot CR moves the hand Hc into the etching processing unit 2e. The center robot CR supports the substrate W on the spin chuck 43a with the hand Hc. Thereafter, the center robot CR moves the hand Hc out of the etching processing unit 2e through the entrance. As a result, the substrate W is unloaded from the etching processing unit 2e.

[0125] In the example shown in Fig. 4, both the etching liquid and the rinsing liquid are pure water. In this case, the drying step may be performed without performing the rinsing step, or the drying step may be performed after the pure water serving as the etching liquid is washed away with pure water serving as the rinsing liquid. In the former case, the electric motor 43d may rotate the substrate W at a high rotation speed while the etching liquid is present on the substrate W. Below, an example will be described in which the drying step is performed without performing the rinsing step after the etching step.

[0126] Next, the electrical configuration of the substrate processing apparatus 1 will be described.

[0127] 5 is a block diagram showing the electrical configuration of the substrate processing apparatus 1. The control device 3 is a computer including a computer main body 3a and a peripheral device 3d connected to the computer main body 3a. The computer main body 3a includes a CPU 3b (central processing unit) that executes various commands and a memory 3c that stores information. The peripheral device 3d includes a storage 3e that stores information such as a program P, a reader 3f that reads information from removable media RM, and a communication device 3g that communicates with other devices such as a host computer.

[0128] The control device 3 is connected to an input device and a display device. The input device is operated when an operator such as a user or a maintenance technician inputs information into the substrate processing apparatus 1. The information is displayed on the screen of the display device. The input device may be any of a keyboard, a pointing device, and a touch panel, or may be other devices. The substrate processing apparatus 1 may be provided with a touch panel display that serves as both an input device and a display device.

[0129] The CPU 3b executes a program P stored in the storage 3e. The program P in the storage 3e may be one that has been pre-installed in the control device 3, or may be one that has been sent from a removable medium RM to the storage 3e via a reader 3f, or may be one that has been sent from an external device such as a host computer to the storage 3e via a communication device 3g.

[0130] The storage 3e and removable medium RM are non-volatile memories that retain their memory even when power is not supplied. The storage 3e is, for example, a magnetic storage device such as a hard disk drive. The removable medium RM is, for example, an optical disk such as a compact disk or a semiconductor memory such as a memory card. The removable medium RM is an example of a computer-readable recording medium on which the program P is recorded. The removable medium RM is a non-transitory tangible recording medium.

[0131] The storage 3e stores a plurality of recipes. A recipe is information that specifies the processing content, processing conditions, and processing procedure of the substrate W. The plurality of recipes differ from one another in at least one of the processing content, processing conditions, and processing procedure of the substrate W. The control device 3 controls the substrate processing apparatus 1 so that the substrate W is processed in accordance with the recipe specified by the host computer. The control device 3 is programmed to execute each process described below.

[0132] Next, an example of processing of the substrate W performed in the substrate processing apparatus 1 will be described.

[0133] 6 is a table showing an example of the number of high-temperature cycles and low-temperature cycles and the order of the high-temperature cycles and low-temperature cycles. In FIG. 6, high-temperature cycles are represented by "H" and low-temperature cycles are represented by "L." In an example of processing a substrate W described below, one substrate W is subjected to N high-temperature cycles and M low-temperature cycles (N and M are both integers of 2 or greater). N may be equal to M, or may be greater than or less than M.

[0134] The high-temperature cycle includes a high-temperature oxidation process and an etching process. The high-temperature oxidation process is an oxidation process in which the substrate W is heated to a high temperature by irradiating it with light while supplying ozone gas to the substrate W. The low-temperature cycle includes a low-temperature oxidation process and an etching process. The low-temperature oxidation process is an oxidation process in which the substrate W is heated to a low temperature (high temperature) lower than the temperature of the substrate W in the high-temperature oxidation process by irradiating it with light while supplying ozone gas to the substrate W.

[0135] The high-temperature oxidation step and the low-temperature oxidation step are examples of the first oxidation step and the second oxidation step. Either the high-temperature oxidation step or the low-temperature oxidation step may be the first oxidation step. The etching step performed after the first oxidation step is the first etching step, and the etching step performed after the second oxidation step is the second etching step. One of the high-temperature cycle and the low-temperature cycle is the first cycle, and the other of the high-temperature cycle and the low-temperature cycle is the second cycle.

[0136] The number of high-temperature cycles, N, the number of low-temperature cycles, M, and the order of the high-temperature and low-temperature cycles are specified in the recipe. N and M are set according to the total removal amount, which represents the difference between the thickness of the molybdenum film 100 (see FIG. 1A) before the first cycle and the thickness of the molybdenum film 100 after all cycles have been performed. If the reduction in thickness of the molybdenum film 100 after one high-temperature cycle is defined as Tn and the reduction in thickness of the molybdenum film 100 after one low-temperature cycle is defined as Tm, the total removal amount can be expressed as Total Removal Amount = Tn × N + Tm × M.

[0137] As long as the total removal amount is the same, the number of high-temperature cycles and low-temperature cycles and the order of the high-temperature cycles and low-temperature cycles may be set in any way. Cases 1 to 5 in Figure 6 show specific examples of the number of high-temperature cycles and low-temperature cycles and the order of the high-temperature cycles and low-temperature cycles.

[0138] Cases 1 to 3 in FIG. 6 show examples in which the number of high-temperature cycles and low-temperature cycles is the same, but the order of the high-temperature cycles and low-temperature cycles is different. As shown in Case 1, N high-temperature cycles may be performed first, followed by M low-temperature cycles. Conversely, as shown in Case 2, M low-temperature cycles may be performed first, followed by N high-temperature cycles. As shown in Case 3, high-temperature cycles and low-temperature cycles may be performed alternately, one each. If N is greater than M in Case 3, it is sufficient to perform a high-temperature cycle at least before or after the alternating high-temperature cycles and low-temperature cycles. The same applies when M is greater than N in Case 3.

[0139] As shown in Case 4 of Figure 6, when three or more high-temperature cycles are performed, the number of low-temperature cycles performed between two high-temperature cycles may be different each time. Case 4 shows an example in which one low-temperature cycle is performed between the first and second high-temperature cycles, two low-temperature cycles are performed between the second and third high-temperature cycles, and three low-temperature cycles are performed between the third and fourth high-temperature cycles. In Case 4, the high-temperature cycles and low-temperature cycles may be interchanged.

[0140] As shown in Case 5 of Figure 6, when four or more high-temperature cycles are performed, the number of low-temperature cycles performed between two high-temperature cycles may vary each time for multiple intervals less than the total number of intervals between the high-temperature cycles. In Case 5, the total number of intervals between high-temperature cycles is three. Case 5 shows an example in which one low-temperature cycle is performed between the first and second high-temperature cycles, two low-temperature cycles are performed between the second and third high-temperature cycles, and one low-temperature cycle is performed between the third and fourth high-temperature cycles. The number of low-temperature cycles varies each time between the first and second intervals or the second and third intervals. In Case 5, the high-temperature cycles and low-temperature cycles may be interchanged.

[0141] The number of low-temperature cycles performed between one high-temperature cycle and the next may be the same every time, as shown in Case 3 of Fig. 6, or may vary regularly or irregularly, as shown in Cases 4 and 5 of Fig. 6. The same applies when the high-temperature cycles and low-temperature cycles are interchanged. When processing multiple substrates W, if the numbers of high-temperature cycles and low-temperature cycles are the same, the number of low-temperature cycles performed between two high-temperature cycles in the processing of one substrate W may be the same every time, while the number of low-temperature cycles performed between two high-temperature cycles in the processing of another substrate W may vary regularly or irregularly.

[0142] 7A and 7B are schematic cross-sectional views showing an example of a cross section of a substrate W after a high-temperature oxidation process or a low-temperature oxidation process has been performed. FIG. 7A shows an example of a cross section of a substrate W after a high-temperature oxidation process has been performed, and FIG. 7B shows an example of a cross section of a substrate W after a low-temperature oxidation process has been performed. FIG. 8 is a graph showing the change in light intensity over time when the high-temperature oxidation process and the low-temperature oxidation process are performed. FIG. 9 is a graph showing the change in temperature of a substrate W over time when the high-temperature oxidation process and the low-temperature oxidation process are performed.

[0143] As described above, the high-temperature oxidation process is an oxidation process in which the substrate W is heated at a high temperature by irradiating it with light while supplying ozone gas to the substrate W. The low-temperature oxidation process is an oxidation process in which the substrate W is heated at a low temperature by irradiating it with light while supplying ozone gas to the substrate W. As shown in FIG. 9, the low temperature is lower than the high temperature. The low temperature and the high temperature are temperatures within the range from the minimum temperature to the maximum temperature described above.

[0144] When the high-temperature oxidation step is performed, the intensity control circuit 29 (see FIG. 3) causes the LED lamp, which is an example of the heat lamp 28, to emit high-intensity light corresponding to a high temperature. As shown in FIG. 9, the high-intensity light is irradiated onto the substrate W, raising the temperature of the substrate W to a high temperature. This allows the temperature of the substrate W to be maintained at a high temperature while ozone gas is supplied to the substrate W.

[0145] On the other hand, when a low-temperature oxidation step is performed, the intensity control circuit 29 causes an LED lamp, which is an example of the heat lamp 28, to emit low-intensity light corresponding to a low temperature. As shown in Fig. 9, the low-intensity light is irradiated onto the substrate W, raising the temperature of the substrate W to a low temperature. This allows the temperature of the substrate W to be maintained at a low temperature while ozone gas is supplied to the substrate W.

[0146] The temperature of the substrate W depends on the intensity of the light irradiated onto the substrate W. As shown in FIG. 8, the high-intensity light is light with a higher irradiance than the low-intensity light. The high-intensity light has a wavelength in the range of 300 to 1000 nm and an irradiance of 10 W / cm. 2 As described above, the light heats the substrate W at a rate of 50°C / sec or more. As can be seen from a comparison of Figures 7A and 7B, a thicker molybdenum oxide film 105 is formed in the high-temperature oxidation process than in the low-temperature oxidation process. Therefore, the amount of reduction in thickness of the molybdenum film 100 after one high-temperature cycle is greater than the amount of reduction in thickness of the molybdenum film 100 after one low-temperature cycle.

[0147] 10 is a flowchart illustrating an example of processing a substrate W according to an embodiment of the present invention. Reference will be made below to FIGS.

[0148] When processing a substrate W in the substrate processing apparatus 1, the substrate W is loaded into the oxidation processing unit 2o (step S1 in FIG. 10). If the recipe specifies that a high-temperature cycle is to be performed (Yes in step S2 in FIG. 10), a high-temperature oxidation step is performed in the oxidation processing unit 2o (step S3 in FIG. 10). If the recipe specifies that a low-temperature cycle is to be performed (No in step S2 in FIG. 10), a low-temperature oxidation step is performed in the oxidation processing unit 2o (step S4 in FIG. 10).

[0149] After the high-temperature oxidation step or the low-temperature oxidation step is performed, the substrate W is unloaded from the oxidation processing unit 2o and loaded into the etching processing unit 2e (step S5 in FIG. 10). Thereafter, the etching process and the drying process are performed in the etching processing unit 2e (step S6 in FIG. 10). This removes the molybdenum oxide film 105 (see FIG. 1B) formed in the high-temperature oxidation step or the low-temperature oxidation step.

[0150] After the etching and drying processes are performed, it is checked whether the number of high-temperature cycles and low-temperature cycles matches the number specified in the recipe (step S7 in FIG. 10). If they do not match (No in step S7 in FIG. 10), the substrate W is unloaded from the etching processing unit 2e and loaded into the same or a different oxidation processing unit 2o as the previous one (step S1 in FIG. 10).

[0151] After the substrate W is loaded into the oxidation processing unit 2o, a high-temperature oxidation step or a low-temperature oxidation step is performed according to the recipe (step S3 or step S4 in FIG. 10), and the substrate W is then loaded from the oxidation processing unit 2o into the same or a different etching processing unit 2e (step S5 in FIG. 10), where it is then subjected to an etching step and a drying step (step S6 in FIG. 10).

[0152] In this way, the processes from step S1 to step S6 are repeated, and the high-temperature cycle and the low-temperature cycle are performed in the order specified in the recipe for the number of times specified in the recipe. When the number of high-temperature cycles and the low-temperature cycles matches the number specified in the recipe (Yes in step S7 of FIG. 10), the substrate W is unloaded from the etching processing unit 2e and loaded into the carrier CA on the load port LP (step S8 of FIG. 10).

[0153] As described above, in this embodiment, the substrate W is heated by irradiating it with light. Furthermore, oxygen gas or ozone gas is supplied to the substrate W while irradiating it with light. As a result, oxygen atoms contained in the oxygen gas or ozone gas bond with molybdenum, and the surface layer 102 of the molybdenum film 100 is converted to molybdenum trioxide. Thereafter, an etching solution is supplied to the substrate W. The molybdenum trioxide dissolves in the etching solution. Therefore, the surface layer 102 of the molybdenum film 100 that has converted to molybdenum trioxide is etched, and the portion of the molybdenum film 100 other than the surface layer 102 that has not converted to molybdenum trioxide remains on the substrate W.

[0154] The thickness of the molybdenum oxide film 105 formed by the conversion to molybdenum trioxide depends on the temperature of the substrate W when oxygen gas or ozone gas is supplied. For example, increasing the temperature of the substrate W increases the thickness of the molybdenum oxide film 105 and decreases the thickness of the molybdenum film 100. When the surface layer 102 of the molybdenum film 100 is oxidized multiple times, if the substrate W is heated at a high temperature each time, the rate at which the molybdenum film 100 thins increases, but it is difficult to precisely control the thickness of the molybdenum film 100. On the other hand, if the substrate W is heated at a low temperature each time, it is easy to precisely control the thickness of the molybdenum film 100, but the rate at which the molybdenum film 100 thins decreases.

[0155] In this embodiment, when the surface layer 102 of the molybdenum film 100 is oxidized, the temperature of the substrate W is changed by changing the intensity of light irradiated onto the substrate W. Therefore, the thickness of the molybdenum film 100 can be controlled more precisely than when the substrate W is heated at a high temperature each time. In addition, the rate at which the molybdenum film 100 is thinned can be increased compared to when the substrate W is heated at a low temperature each time. This allows the molybdenum film 100 to be thinned in a shorter time while maintaining the dimensional accuracy of the molybdenum film 100.

[0156] In this embodiment, the substrate W is heated by irradiating it with light emitted from an LED lamp, which is an example of a heat lamp 28. Therefore, the temperature of the substrate W can be increased more rapidly than when the substrate W is heated with a hot plate, that is, when Joule heat is transferred to the substrate W by thermal conduction. Furthermore, power consumption can be reduced compared to when the substrate W is heated with other heat sources such as a hot plate or halogen lamp. In addition, because the LED lamp has a long life, the frequency of component replacement can be reduced compared to when the substrate W is heated with other heat lamps such as a halogen lamp.

[0157] In this embodiment, the LED lamp emits light with a wavelength in the range of 300 to 1000 nm. When the temperature of the silicon wafer is 500°C or less and the wavelength of the light exceeds this range, the light absorption rate by the silicon wafer is low, and therefore, the temperature of the substrate W cannot be rapidly increased unless high-intensity light is irradiated onto the substrate W. Increasing the light intensity increases power consumption and requires the use of a larger heating lamp. Irradiating the substrate W with light with a wavelength within this range increases the light absorption rate, allowing the substrate W to be heated efficiently.

[0158] In this embodiment, instead of having a second heat lamp, different from a first heat lamp that emits light of a first intensity, emit light of a second intensity, one heat lamp 28 emits light of a first intensity and then emits light of a second intensity before or after that. In other words, by switching the intensity of light emitted from the heat lamp 28, the heat lamp 28 emits light of the first intensity and light of the second intensity. Therefore, the number of heat lamps 28 can be reduced compared to when different first and second heat lamps are provided.

[0159] In this embodiment, the substrate W is heated while oxygen gas or ozone gas is supplied to the substrate W, and then an etching solution is supplied to the substrate W. Thereafter, the substrate W is heated again while oxygen gas or ozone gas is supplied to the substrate W, and then an etching solution is supplied to the substrate W. In other words, oxidation of the molybdenum film 100 and etching of the molybdenum oxide film 105 are alternately repeated multiple times. This allows the thickness of the molybdenum film 100 to be reduced in stages, and the thickness of the molybdenum film 100 to be adjusted in stages.

[0160] In this embodiment, a first cycle is performed three or more times, in which the substrate W is heated to a first temperature by irradiating it with light of a first intensity while supplying oxygen gas or ozone gas to the substrate W, and then an etching solution is supplied to the substrate W. Furthermore, a second cycle is performed one or more times, in which the substrate W is heated to a second temperature by irradiating it with light of a second intensity while supplying oxygen gas or ozone gas to the substrate W, and then an etching solution is supplied to the substrate W. One of the high-temperature cycle and the low-temperature cycle is the first cycle, and the other of the high-temperature cycle and the low-temperature cycle is the second cycle.

[0161] The number of second cycles performed between two first cycles varies each time at intervals equal to or less than the total number of intervals between the first cycles. For example, when three first cycles are performed, one second cycle is performed between the first and second first cycles, and two second cycles are performed between the second and third first cycles. When four first cycles are performed, one second cycle is performed between the first and second first cycles, and two second cycles are performed between the second and third first cycles. The number of second cycles performed between the third and fourth first cycles may be one or two, or may be zero or a value greater than or equal to three.

[0162] When the first cycle is performed individually on multiple substrates W, if the first cycles are performed at the same time, the consumption of processing fluids such as processing gas and processing liquid, and the consumption of electricity may increase locally. By changing the number of second cycles performed between two first cycles, it is possible to reduce such local increases and to level out the consumption of processing fluids and electricity per hour.

[0163] In this embodiment, the substrate W is heated while supplying ozone gas instead of oxygen gas to the substrate W. Therefore, the surface layer 102 of the molybdenum film 100 can be converted into molybdenum trioxide more efficiently than when the substrate W is heated while supplying oxygen gas to the substrate W. This reduces the time required to convert the surface layer 102 of the molybdenum film 100 into molybdenum trioxide, thereby increasing the throughput (the number of substrates W processed per unit time) of the substrate processing apparatus 1.

[0164] In this embodiment, a water-containing liquid containing water as a main component is supplied to the substrate W to etch the substrate W. While molybdenum trioxide dissolves in water, molybdenum is insoluble or barely soluble in water. Therefore, the surface layer 102 of the molybdenum film 100 that has been converted to molybdenum trioxide can be removed from the substrate W without using a chemical solution. This simplifies the treatment of wastewater and reduces the burden on the environment compared to when the etching solution is a chemical solution.

[0165] In this embodiment, the molybdenum film 100 is oxidized and etched within one substrate processing apparatus 1. In other words, after the substrate W is loaded into the substrate processing apparatus 1 through the load port LP, the substrate W is not unloaded from the substrate processing apparatus 1 through the load port LP until the oxidation of the molybdenum film 100 and the etching of the molybdenum oxide film 105 are completed. Therefore, the time required to transport the substrate W can be shortened compared to when the oxidation of the molybdenum film 100 and the etching of the molybdenum oxide film 105 are performed in separate substrate processing apparatuses.

[0166] Other embodiments The oxidation process may include three or more oxidation processes with different set temperatures for the substrate W. For example, in addition to the high-temperature oxidation process and the low-temperature oxidation process, the oxidation process may include an intermediate-temperature oxidation process in which the substrate W is heated to an intermediate temperature that is lower than the high temperature and higher than the low temperature by irradiating the substrate W with light of an intermediate intensity that is weaker than the high intensity and stronger than the low intensity while oxygen gas or ozone gas is supplied to the substrate W.

[0167] Instead of performing the high-temperature oxidation process and the low-temperature oxidation process by changing the intensity of light emitted from the heating lamps 28 between high and low intensities, it is also possible to provide high-intensity heating lamps that irradiate the substrate W with high-intensity light and low-intensity heating lamps that irradiate the substrate W with low-intensity light. In this case, the high-intensity heating lamp and the low-intensity heating lamp may be arranged in the same oxidation treatment unit 2o, or in separate oxidation treatment units 2o.

[0168] Instead of performing spin drying, which dries the substrate W by rotating the substrate W at high speed, the liquid adhering to the substrate W may be replaced with the organic solvent liquid by supplying vapor of an organic solvent, such as IPA, which is more volatile than water, to the substrate W. Additionally or alternatively, evaporation of the liquid adhering to the substrate W may be promoted by reducing the air pressure in the space in which the substrate W to be dried is placed.

[0169] If the amount of reduction in the thickness of the molybdenum film 100 is small, the number of high-temperature cycles and low-temperature cycles performed on one substrate W may be one each.

[0170] Instead of oxidizing the multiple substrates W one by one, the multiple substrates W may be oxidized all at once. That is, the multiple substrates W may be simultaneously heated by irradiating them with light while oxygen gas or ozone gas is simultaneously supplied to the multiple substrates W. When oxidizing the multiple substrates W all at once, the multiple substrates W may be etched one by one, or the multiple substrates W may be etched all at once. When etching the multiple substrates W all at once, the multiple substrates W may be oxidized one by one.

[0171] Some of the steps included in the high-temperature cycle and the low-temperature cycle may be performed in another substrate processing apparatus, rather than performing all of the high-temperature cycle and the low-temperature cycle in the substrate processing apparatus 1. For example, the high-temperature oxidation step and the low-temperature oxidation step may be performed in the substrate processing apparatus 1, and the etching step may be performed in another substrate processing apparatus. Alternatively, the high-temperature cycle including the high-temperature oxidation step and the etching step may be performed in the substrate processing apparatus 1, and the low-temperature cycle including the low-temperature oxidation step and the etching step may be performed in another substrate processing apparatus.

[0172] The substrate processing apparatus 1 is not limited to an apparatus for processing a disk-shaped substrate W, but may be an apparatus for processing a polygonal substrate W.

[0173] Any two or more of the above-mentioned features may be combined. Any two or more of the above-mentioned steps may be combined.

[0174] The oxidation treatment unit 2o is an example of first and second oxidation means. The gas supply port 31a is an example of first and second gas supply ports. The heat lamp 28 is an example of first and second heat lamps. The etching treatment unit 2e is an example of first and second etching means. The etching liquid nozzle 44a is an example of first and second etching liquid nozzles.

[0175] In addition, various design modifications can be made within the scope of the claims. [Explanation of symbols]

[0176] 1: Substrate processing equipment 2e: Etching processing unit (first and second etching means) 2o: Oxidation processing unit (first and second oxidation means) 4:Transportation system 28: Heating lamps (first and second heating lamps) 31a: Gas supply port (first and second gas supply port) 44a: Etchant nozzles (first and second etchant nozzles) 100: Molybdenum film 102: Surface layer of molybdenum film 105: Molybdenum oxide film 107: Silicon wafer W: Substrate

Claims

1. a first oxidation step including a first gas supply step of supplying oxygen gas or ozone gas to a substrate, and a first heating step of heating the substrate at a first temperature by irradiating the substrate with light of a first intensity, the first gas supply step and the first heating step being carried out simultaneously to change a surface layer of a molybdenum film formed on the substrate into molybdenum trioxide without changing a portion other than the surface layer of the molybdenum film into molybdenum trioxide; a first etching step of supplying an etching solution to the substrate, thereby dissolving the surface layer of the molybdenum film that has been converted to molybdenum trioxide in the first oxidation step into the etching solution, while leaving portions other than the surface layer of the molybdenum film on the substrate; a second oxidation step including a second gas supply step of supplying the oxygen gas or ozone gas to the substrate, and a second heating step of heating the substrate at a second temperature higher or lower than the first temperature by irradiating the substrate with light of a second intensity higher or lower than the first intensity, the second gas supply step and the second heating step being simultaneously performed before or after the first oxidation step and the first etching step, thereby changing the surface layer of the molybdenum film to the molybdenum trioxide without changing portions other than the surface layer of the molybdenum film to the molybdenum trioxide; a second etching step of supplying the etching solution to the substrate, thereby dissolving the surface layer of the molybdenum film that has been converted to molybdenum trioxide in the second oxidation step into the etching solution, while leaving portions other than the surface layer of the molybdenum film on the substrate.

2. 2. The substrate processing method according to claim 1, wherein at least one of the first heating step and the second heating step is a step of irradiating the substrate with light emitted from an LED (light emitting diode) lamp.

3. the substrate includes a silicon wafer and the molybdenum film supported on the silicon wafer; 3. The substrate processing method according to claim 2, wherein the wavelength of the light emitted from the LED lamp is within a range of 300 to 1000 nm.

4. the first heating step includes a step of irradiating the substrate with light of the first intensity by causing a heat lamp to emit light of the first intensity; The method of claim 1 , further comprising causing the heat lamp to emit light of the second intensity.

5. 2. The substrate processing method according to claim 1, wherein at least one of a first cycle including the first oxidation step and the first etching step and a second cycle including the second oxidation step and the second etching step is performed a plurality of times.

6. 6. The substrate processing method of claim 5, wherein when the first cycle is performed three or more times, the number of the second cycles performed between the first cycle and the next first cycle is different each time at a plurality of intervals equal to or less than the total number of intervals between the first cycles.

7. 7. The substrate processing method according to claim 1, wherein the first gas supplying step and the second gas supplying step are steps of supplying the ozone gas to the substrate.

8. 7. The substrate processing method according to claim 1, wherein the etching liquid is a water-containing liquid containing water as a main component.

9. 7. The substrate processing method according to claim 1, wherein the first oxidation step, the first etching step, the second oxidation step, and the second etching step are performed in one substrate processing apparatus.

10. a first oxidation means including a first gas supply port for supplying oxygen gas or ozone gas to a substrate and a first heating lamp for heating the substrate at a first temperature by irradiating the substrate with light of a first intensity, the first oxidation means heating the substrate at the first temperature by irradiating the substrate with light of the first intensity while supplying the oxygen gas or ozone gas to the substrate, thereby converting a surface layer of a molybdenum film formed on the substrate into molybdenum trioxide without converting portions other than the surface layer of the molybdenum film into molybdenum trioxide; a first etching means including a first etching solution nozzle for supplying an etching solution to the substrate, the etching solution being supplied to the substrate to dissolve the surface layer of the molybdenum film, which has been converted to molybdenum trioxide by the first oxidizing means, in the etching solution while leaving portions other than the surface layer of the molybdenum film on the substrate; a second oxidizing means that may be the same as or different from the first oxidizing means, the second oxidizing means including: a second gas supply port that is the same as or different from the first gas supply port and that supplies the oxygen gas or ozone gas to the substrate; and a second heat lamp that is the same as or different from the first heat lamp and that heats the substrate at a second temperature that is higher or lower than the first temperature by irradiating the substrate with light of a second intensity that is stronger or weaker than the first intensity, the second oxidizing means being the same as or different from the first oxidizing means and that converts the surface layer of the molybdenum film to molybdenum trioxide without converting portions other than the surface layer of the molybdenum film to molybdenum trioxide by heating the substrate at the second temperature by irradiating it with light of the second intensity while supplying the oxygen gas or ozone gas to the substrate; a second etching means, which may be the same as or different from the first etching means, including a second etching solution nozzle, which supplies the etching solution to the substrate, and which, by supplying the etching solution to the substrate, dissolves the surface layer, which has been converted to molybdenum trioxide by the second oxidizing means, in the etching solution while leaving a portion of the molybdenum film other than the surface layer on the substrate; a transfer system that transfers the substrate among the first oxidation means, the first etching means, the second oxidation means, and the second etching means.

Images