Processing device and cleaning processing method

Abstract

To provide a technique capable of stably performing cleaning processing.SOLUTION: A processing device includes: a processing container; a temperature sensor that detects a temperature in the processing container; a gas supply unit that supplies a fluorine-containing cleaning gas into the processing container; a pressure adjustment unit that adjusts a pressure in the processing container; and a control unit that controls the gas supply unit and the pressure adjustment unit to perform cleaning processing for removing a deposited film in the processing container. The control unit stores, in the storage unit, a vapor pressure curve that associates the temperature in the processing container with a vapor pressure of water in the processing container. In the cleaning processing, the control unit sets a target pressure equal to or below the vapor pressure curve by referring to the storage unit on the basis of the detected temperature detected by the temperature sensor and the vapor pressure curve, and controls the pressure adjustment unit such that the pressure in the processing container becomes equal to the target pressure.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a processing apparatus and a cleaning processing method.

Background Art

[0002] A processing apparatus performs substrate processing such as forming a film on a substrate accommodated in a processing chamber. Since a film also deposits in the processing chamber along with the substrate processing, the processing apparatus performs cleaning processing at an appropriate timing. For example, in the cleaning processing, the processing apparatus supplies a cleaning gas into the processing chamber to etch (remove) the deposited film.

[0003] Patent Document 1 discloses a technique for calculating an etching rate based on the temperature in a processing chamber and setting an etching time based on the calculated etching rate in order to prevent over-etching in this cleaning processing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present disclosure provides a technique capable of stably performing cleaning processing.

Means for Solving the Problems

[0006] According to one aspect of the present disclosure, there is provided a processing apparatus including a processing container, a temperature sensor that detects the temperature inside the processing container, a gas supply unit that supplies a cleaning gas containing fluorine into the processing container, a pressure adjustment unit that adjusts the pressure inside the processing container, and a control unit that controls the gas supply unit and the pressure adjustment unit to perform a cleaning process for removing a deposited film inside the processing container. The control unit stores in a storage unit a vapor pressure curve associating the temperature inside the processing container with the vapor pressure of water inside the processing container. In the cleaning process, the control unit refers to the storage unit and sets a target pressure below the vapor pressure curve based on the detected temperature detected by the temperature sensor and the vapor pressure curve, and controls the pressure adjustment unit so that the pressure inside the processing container becomes the target pressure.

Advantages of the Invention

[0007] According to one aspect, the cleaning process can be stably performed.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are given to the same components, and redundant descriptions may be omitted.

[0010] 〔Processing Apparatus〕 FIG. 1 is an explanatory diagram schematically showing a configuration example of a processing apparatus 1 according to an embodiment. As shown in FIG. 1, a processing apparatus 1 according to an embodiment is a vertical processing apparatus that arranges a plurality of substrates W in a vertical direction (up and down direction) and performs substrate processing such as film formation on each of these substrates. The substrate W is, for example, a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer, or a glass substrate.

[0011] The processing apparatus 1 includes a processing chamber 10, a gas supply unit 30, an exhaust unit 40, a heating unit 50, a cooling unit 60, a temperature sensor 70, and a control unit 90.

[0012] The processing chamber 10 is formed in a cylindrical shape capable of accommodating a plurality of substrates W along the vertical direction. For example, the processing chamber 10 includes a cylindrical inner cylinder 11 having a ceiling and an open lower end, and a cylindrical outer cylinder 12 that covers the outside of the inner cylinder 11 and has a ceiling and an open lower end. The inner cylinder 11 and the outer cylinder 12 are formed of a heat-resistant material such as quartz and exhibit a double structure arranged coaxially with each other. Note that the processing chamber 10 is not limited to a double structure, and may be a single cylinder structure or a multi-layer structure composed of three or more cylinders.

[0013] The inner cylinder 11 has a flat ceiling, while the outer cylinder 12 has a dome-shaped ceiling. At a predetermined circumferential position of the inner cylinder 11, a housing portion 13 for housing a gas nozzle 31 along the vertical direction is formed. As an example, the housing portion 13 is formed inside a convex portion 14 that projects a part of the side wall of the inner cylinder 11 radially outward.

[0014] On the side wall of the inner cylinder 11 on the opposite side facing the accommodating portion 13, an opening 15 that is long in the vertical direction is formed. The opening 15 exhausts the gas inside the inner cylinder 11 to the space P1 between the inner cylinder 11 and the outer cylinder 12. The length of the opening 15 in the vertical direction is preferably the same as the length of the wafer boat 16 in the vertical direction or longer than the wafer boat 16 in the vertical direction.

[0015] The lower end of the processing container 10 is supported by, for example, a cylindrical manifold 17 formed of stainless steel. A flange 18 is formed at the upper end of the manifold 17, and the flange 18 supports the flange 12f at the lower end of the outer cylinder 12. A seal member 19 for hermetically sealing the interiors of the outer cylinder 12 and the manifold 17 is provided between the flange 12f and the flange 18.

[0016] An annular support portion 20 protrudes radially inward on the inner wall of the upper portion of the manifold 17, and the support portion 20 supports the lower end of the inner cylinder 11. A lid body 21 is hermetically attached to the opening at the lower end of the manifold 17 via a seal member 22. That is, the lid body 21 hermetically closes the opening on the lower end side of the manifold 17. The lid body 21 is formed in a flat plate shape of, for example, stainless steel.

[0017] A rotating shaft 24 that rotatably supports the wafer boat 16 penetrates through the central portion of the lid body 21 via a magnetic fluid seal portion 23. The lower portion of the rotating shaft 24 is supported by an arm 25A of a lifting mechanism 25 constituted by a boat elevator or the like. The processing apparatus 1 can move the arm 25A of the lifting mechanism 25 up and down to move the lid body 21 and the wafer boat 16 up and down integrally, and insert and remove the wafer boat 16 into and from the processing container 10.

[0018] A rotating plate 26 is provided at the upper end of the rotating shaft 24, and the wafer boat 16 that holds the substrate W via a heat insulating unit 27 is placed on the rotating plate 26. The wafer boat 16 is a substrate holder that holds the substrate W at predetermined intervals in the vertical direction. By the wafer boat 16, each substrate W is held along the horizontal direction.

[0019] Figure 2 is an explanatory diagram showing an enlarged configuration of the wafer boat 16, the lid 21, and the heat insulation unit 27. The heat insulation unit 27 is configured by arranging a plurality of large fins 28 made of, for example, quartz in a shelf shape, and arranging a plurality of small fins 29 made of, for example, quartz, which are heat insulating materials smaller than the size of the large fins 28, in a shelf shape above the plurality of large fins 28. The size of the large fins 28 is set to be approximately the same diameter as the diameter of the substrate W.

[0020] The heat insulation unit 27 is arranged at a location where the temperature change is large in the processing container 10 because there are inlets and outlets of the gas supply unit 30, the exhaust unit 40, or other temperature change elements in the vicinity of its side. The heat insulation unit 27 insulates these temperature changes to stabilize the temperature in the processing container 10 above the heat insulation unit 27.

[0021] Returning to FIG. 1, the gas supply unit 30 is inserted into the processing container 10 through the manifold 17. The gas supply unit 30 introduces gases such as a processing gas, a cleaning gas, and a purge gas into the inside of the inner cylinder 11. For example, the gas supply unit 30 includes a gas nozzle 31 for introducing a processing gas and a purge gas, and a gas nozzle 32 for introducing a cleaning gas.

[0022] The gas nozzle 31 is made of quartz, extends along the vertical direction inside the inner cylinder 11, and is provided so as to bend in an L shape at the lower end and penetrate inside and outside the manifold 17. The gas nozzle 31 is provided with a plurality of gas holes 31h at predetermined intervals along the vertical direction, and discharges gas in the horizontal direction through each gas hole 31h. The predetermined interval is set to be the same as, for example, the interval between each substrate W supported by the wafer boat 16. Further, the vertical position of the gas holes 31h is set to be located in the middle between adjacent substrates W in the vertical direction so that gas can smoothly flow through the space between each substrate W.

[0023] The gas nozzle 31 is, for example, an injector tube that supplies a processing gas and a purge gas. The gas supply unit 30 supplies the processing gas and the purge gas into the processing container 10 while controlling the flow rate outside the processing container 10. The processing gas may be appropriately selected according to the film type to be formed on the substrate W. When forming a silicon oxide film, for example, as the processing gas, a silicon-containing gas such as dichlorosilane (DCS) gas and an oxidizing gas such as ozone (O 3 ) gas can be used. As the purge gas, for example, nitrogen (N 2 ) gas or argon (Ar) gas can be used.

[0024] The gas nozzle 32 is made of quartz and is provided so as to extend in the vertical direction at a position below the wafer boat 16. The gas nozzle 32 is provided so as to bend in an L shape at the lower end and penetrate both the inside and outside of the manifold 17. The upper end of the gas nozzle 32 is open, and the gas is discharged upward from the opening. The gas nozzle 32 is, for example, an injector tube that supplies a cleaning gas and a purge gas. The gas supply unit 30 supplies the cleaning gas into the processing container 10 while adjusting the flow rate by a flow rate regulator (not shown) installed outside the processing container 10. The cleaning gas may be appropriately selected according to the film type formed in the processing container 10. When the film formed in the processing container 10 is a silicon oxide film, examples of the cleaning gas include hydrogen fluoride (HF) gas, fluorine (F 2 ) gas, chlorine trifluoride (ClF 3 ) gas, nitrogen trifluoride (NF 3 ) gas, and other fluorine-containing gases.

[0025] Note that the gas supply unit 30 may be configured to include a plurality of gas nozzles 31 in order to supply a plurality of types of processing gases or purge gases individually, or may be configured to supply the processing gas, the cleaning gas, and the purge gas into the processing container 10 from one gas nozzle 31. In short, the number of the gas nozzles 31 and 32 is not limited to the example in FIG. 1.

[0026] The exhaust unit 40 exhausts the gas inside the processing vessel 10 to the outside. The gas supplied by the gas supply unit 30 flows out from the opening 15 of the inner cylinder 11 into the space P1 between the inner cylinder 11 and the outer cylinder 12, and is exhausted through the gas outlet 41. The gas outlet 41 is a side wall at the upper part of the manifold 17 and is formed above the support part 20. An exhaust path 42 of the exhaust unit 40 is connected to the gas outlet 41. The exhaust unit 40 includes a pressure regulating valve 43 and a vacuum pump 44 in order from the upstream to the downstream of the exhaust path 42. The exhaust unit 40 sucks the gas inside the processing vessel 10 by the vacuum pump 44 and adjusts the pressure inside the processing vessel 10 by adjusting the flow rate of the gas to be exhausted by the pressure regulating valve 43.

[0027] The heating unit 50 is installed so as to cover the outside of the processing vessel 10 with a cylindrical heat insulating material 51 having a ceiling, and heats the substrate W inside the processing vessel 10. The heat insulating material 51 is formed mainly of silica and alumina. As an example, the heating unit 50 is attached to a base plate 54 supported by the flange 12f of the outer cylinder 12. The heating unit 50 is not particularly limited as long as it can heat the substrate W inside the processing vessel 10. For example, an infrared heater that radiates infrared rays to heat the processing vessel 10 can be applied. In this case, a linear heating element 52 is provided spirally or meanderingly on the inner circumference of the heat insulating material 51. The heating element 52 can be temperature-controlled by dividing it into a plurality of zones in the height direction of the heating unit 50. Hereinafter, the plurality of zones are referred to as "TOP", "C-T", "CTR", "C-B", and "BTM" in order from above. The heating element 52 is held on the inner wall surface of the heat insulating material 51 via a holding part (not shown).

[0028] In order to hold the shape of the heat insulating material 51 and reinforce the heat insulating material 51, the outer circumference of the heat insulating material 51 is covered with a metal outer skin 53 such as stainless steel. Further, in order to suppress the heat influence to the outside of the heating unit 50, the outer circumference of the outer skin 53 is covered with a water-cooled jacket (not shown).

[0029] The cooling unit 60 supplies a cooling fluid such as air toward the processing container 10 to cool the substrate W within the processing container 10. The cooling unit 60 supplies the cooling fluid toward the processing container 10, for example, when rapidly cooling the substrate W after heat treatment. Further, the cooling unit 60 may supply the cooling fluid toward the inside of the processing container 10 in a cleaning process for etching the deposited film within the processing container 10. The cooling unit 60 includes a fluid flow path 61, a blowing hole 62, a distribution path 63, a cooling fluid flow rate adjustment unit 64, and a waste heat outlet 65.

[0030] A plurality of fluid flow paths 61 are formed along the height direction and the circumferential direction on the outside (outer skin 53) of the heat insulating material 51. The blowing holes 62 are formed to penetrate the heat insulating material 51 from each fluid flow path 61, and blow out the cooling fluid into the space P2 between the outer cylinder 12 and the heat insulating material 51. A plurality of distribution paths 63 are installed outside the outer skin 53 to distribute and supply the cooling fluid to each fluid flow path 61.

[0031] The cooling fluid flow rate adjustment unit 64 is provided for each of the plurality of distribution paths 63 to adjust the flow rate of the cooling fluid supplied to the fluid flow path 61.

[0032] The waste heat outlet 65 is provided above the plurality of blowing holes 62 to discharge the cooling fluid supplied into the space P2 to the outside of the processing apparatus 1. The cooling fluid discharged to the outside of the processing apparatus 1 is cooled by, for example, a heat exchanger (not shown) and supplied again to the distribution path 63. Alternatively, the cooling fluid discharged to the outside of the processing apparatus 1 may be discarded without being reused.

[0033] The temperature sensor 70 is provided inside the inner cylinder 11 to detect the temperature inside the processing container 10. However, the temperature sensor 70 only needs to be provided at a position where it can detect the temperature inside the processing container 10. For example, it may be provided in the space P1 between the inner cylinder 11 and the outer cylinder 12. The temperature sensor 70 has a plurality (five in this embodiment) of temperature sensors 71 to 75 at different positions in the height direction corresponding to the plurality of zones described above. The temperature sensors 71 to 75 are provided according to the zones "TOP", "C-T", "CTR", "C-B", and "BTM", respectively. The plurality of temperature sensors 71 to 75 can apply thermocouples, resistance temperature detectors, etc. The temperature sensor 70 transmits the temperatures detected for each of the plurality of temperature sensors 71 to 75 to the control unit 90, respectively.

[0034] The control unit 90 of the processing apparatus 1 can apply a computer having one or more processors 91, a memory 92, an input / output interface (not shown), and an electronic circuit. The processor 91 is a combination of one or more of a CPU, an ASIC, an FPGA, a circuit composed of a plurality of discrete semiconductors, etc. The memory 92 includes a volatile memory and a non-volatile memory (e.g., a compact disk, a DVD, a hard disk, a flash memory, etc.), and stores a program for operating the processing apparatus 1 and recipes (process conditions) for substrate processing and cleaning processing.

[0035] The processor 91 controls each component of the processing apparatus 1 in substrate processing by executing the program stored in the memory 92. In substrate processing, the processor 91 operates the elevating mechanism 25 to accommodate the wafer boat 16 on which a plurality of substrates W are placed inside the processing container 10. When the lid 21 lifted by the elevating mechanism 25 contacts the manifold 17, the bottom of the processing container 10 is hermetically sealed.

[0036] Then, the processor 91 reduces the pressure inside the processing chamber 10 by the exhaust unit 40 and heats the processing chamber 10 by the heating unit 50. Further, the processor 91 controls the gas supply unit 30 to supply the processing gas into the inner cylinder 11 through the gas nozzle 31. At this time, the processor 91 controls the opening degree of the pressure regulating valve 43 of the exhaust unit 40 while sucking the processing gas by the vacuum pump 44, thereby adjusting the pressure inside the processing chamber 10. As a result, inside the processing chamber 10, substrate processing is performed in which an appropriate film is formed on the substrate W based on the heating of the substrate W and the processing gas supplied from the gas nozzle 31.

[0037] After the substrate processing is completed, the processor 91 stops the supply of the processing gas into the processing chamber 10, further lowers the elevating mechanism 25, and separates the wafer boat 16 from the processing chamber 10. Further, by taking out each substrate W from the wafer boat 16 by a transfer device (not shown), the processing apparatus 1 becomes a state in which new substrate processing is possible.

[0038] With the implementation of the above substrate processing, a deposited film is deposited inside the processing chamber 10. For example, in the substrate processing for forming a silicon oxide film, SiO 2 is deposited. This type of deposited film is deposited on the surfaces of the inner cylinder 11 and the outer cylinder 12, the gas nozzle 31, the gas outlet 41, the exhaust path 42, and the like. Therefore, the processing apparatus 1 performs a cleaning process for etching (removing) the deposited film in regular maintenance and the like.

[0039] The cleaning process is, for example, by supplying HF, which is a fluorine-containing gas, from the gas nozzle 32, and as shown in the following reaction formula (1), reacting SiO 2 with fluorine to change it to silicon tetrafluoride (SiF 4 ). SiO 2 (s)+4HF(g)→SiF 4 +2H 2 O(l) ···(1)

[0040] In addition, the water generated in Reaction Formula (1) reacts with hydrogen fluoride gas to produce hydrofluoric acid (HF(aq)) as shown in the following Reaction Formula (2). HF(g)+H 2 O(l)→HF(aq) ···(2)

[0041] And hydrofluoric acid can further etch the silicon oxide film as shown in the following Reaction Formula (3). SiO 2 (s)+4HF(aq)→SiF 4 +6H 2 O(l) ···(3)

[0042] Here, the reaction rate of the above Reaction Formula (1) is very small compared to the reaction rates of Reaction Formula (2) and Reaction Formula (3). Therefore, it is preferable to generate water (H 2 O) as vapor to promote the reactions of Reaction Formula (2) and Reaction Formula (3). Thereby, the efficiency of the cleaning process can be improved. However, if the generated water changes from a gas (water vapor) to a liquid (liquid water) and adheres to the components such as the wall surface inside the processing container 10, only the reaction at that location is greatly promoted, resulting in over-etching where the SiO 2 originally coated on each component inside the processing container 10 is damaged or peeled off. That is, in order to etch uniformly without causing uneven etching of the deposited film in the cleaning process, it is important to maintain the state of water vapor inside the processing container 10. Note that the "etching unevenness" in this specification is not limited to the state where over-etching occurs in a part of the components inside the processing container 10, but also includes the state where the deposited film is removed unevenly in the cleaning process.

[0043] In addition, the processing apparatus 1 stops the operation of the heating unit 50 during the cleaning process. Therefore, the temperature inside the processing container 10 during the cleaning process is affected by the surrounding environment (for example, the environment of the clean room in the factory) where the processing apparatus 1 is installed, and thus varies between different apparatuses even of the same model.

[0044] FIG. 3 is a chart illustrating the temperature of the processing container 10 during the cleaning process. For example, as shown in FIG. 3, the temperature of the processing container 10 of the processing apparatuses 1 (apparatuses A to E) installed in the factory varies between about 30° C. and 38° C. due to facility factors of the factory and the like in the non-operating state of the heating unit 50. In the cleaning process, the processing apparatus 1 may operate the cooling unit 60. Even when the cooling unit 60 is operated, since the air supplied to the processing container 10 depends on the temperature of the surrounding environment, the processing container 10 will still perform the cleaning process at a temperature corresponding to the surrounding environment.

[0045] As an example, if the processing apparatus 1 is installed near a facility with a large heat radiation, the temperature inside the processing container 10 will naturally increase. Or, if the processing container 10 is installed near an air conditioning facility, the temperature inside the processing container 10 will decrease due to the downflow of the air conditioning facility hitting it, etc. That is, the processing apparatus 1 will perform the cleaning process at different temperatures according to the installed surrounding environment for each apparatus.

[0046] Here, in the cleaning process, if apparatuses A to E perform the cleaning process at different temperatures while keeping the pressure inside the processing containers 10 of apparatuses A to E the same, for example, in the apparatus with a lower temperature, the reactions of reaction formulas (1) to (3) will proceed and liquid water will be generated inside the processing container 10. This liquid water may cause etching unevenness inside the processing container 10. Therefore, the control unit 90 according to the present embodiment optimizes the cleaning process by controlling the operation of the cleaning process based on the temperature inside the processing container 10 detected by the temperature sensor 70.

[0047] FIG. 4 is a block diagram showing the functional blocks of the control unit 90 of the cleaning process. The processor 91 forms a temperature acquisition unit 100, a vapor pressure extraction unit 101, a pressure calculation unit 102, a pressure control unit 103, and a gas supply control unit 104 as shown in FIG. 4 under the execution of a program in the cleaning process.

[0048] The temperature acquisition unit 100 acquires the detected temperature inside the processing container 10 detected by the temperature sensor 70. As described above, the temperature sensor 70 includes five temperature sensors 71 to 75, and the temperature acquisition unit 100 can acquire the temperature for each of the five zones along the height direction of the wafer boat 16 by this temperature sensor 70. Note that the number of temperatures inside the processing container 10 detected by the temperature sensor 70 may be less than five (including one) or more than five.

[0049] FIG. 5 is a diagram showing an example of the temperature detected by the temperature sensor 70. In the example of FIG. 5, the temperature at the "TOP" position is 34°C, the temperature at the "C-T" position is 33°C, the temperature at the "CTR" position is 32°C, the temperature at the "C-B" position is 31°C, and the temperature at the "BTM" position is 30°C. Further, the temperature acquisition unit 100 stores the detected temperature inside the processing container 10 acquired from the temperature sensor 70 in the memory 92.

[0050] Furthermore, when the temperature for each of the five zones is detected, the temperature acquisition unit 100 selects or calculates one detected temperature to be output to the vapor pressure extraction unit 101 based on the detected temperature stored in the memory 92. At this time, the temperature acquisition unit 100 may calculate the average value or the median value of the temperatures for each of the five zones, or may select the maximum temperature and the minimum temperature among the temperatures for each of the five zones. In the example of FIG. 5, the average value (32°C) of the temperatures for each of the five zones is calculated.

[0051] The vapor pressure extraction unit 101 extracts the vapor pressure of the water inside the processing container 10 based on the detected temperature output from the temperature acquisition unit 100. "Vapor pressure" refers to the pressure of the gas at the gas-liquid equilibrium where the number of molecules becoming gas and the number of molecules returning to the liquid are balanced at the acquired detected temperature. Therefore, the vapor pressure extraction unit 101 previously holds the vapor pressure curve 200 of water corresponding to the detected temperature in the internal vapor pressure curve storage unit 101a.

[0052] FIG. 6 is a graph illustrating the vapor pressure curve 200 of water. As shown in FIG. 6, the vapor pressure curve 200 of water shows a tendency that the pressure increases non-linearly as the temperature rises when the horizontal axis represents temperature and the vertical axis represents pressure. In the graph of FIG. 6, the part that exactly overlaps the vapor pressure curve 200 is in the state of vapor-liquid equilibrium. The part above the vapor pressure curve 200 is in a state where liquid is generated by the condensation of water vapor exceeding the saturated water vapor pressure. On the contrary, the part below the vapor pressure curve 200 can exist in the processing container 10 as gaseous water (water vapor). As described above, when the water generated by the reaction formula (1) becomes liquid water and adheres to the inside of the processing container 10, it becomes a factor causing uneven etching of the deposited film. Therefore, in the cleaning process, the control unit 90 performs control so that the target pressure inside the processing container 10 overlaps the vapor pressure curve 200 or is located below the vapor pressure curve 200.

[0053] Specifically, when the vapor pressure extraction unit 101 receives the detected temperature from the temperature acquisition unit 100, it reads out the vapor pressure curve 200 stored in the vapor pressure curve storage unit 101a and recognizes the vapor pressure (hereinafter also referred to as the calculated pressure) that overlaps the vapor pressure curve 200. That is, as shown by the dotted line in FIG. 6, the vapor pressure extraction unit 101 extracts the calculated pressure (35.7 [Torr] ≒ 4759.61 [Pa]) at which vapor-liquid equilibrium occurs at the acquired detected temperature (for example, 32°C) through the vapor pressure curve 200. Then, the vapor pressure extraction unit 101 outputs the extracted calculated pressure to the pressure calculation unit 102.

[0054] When the pressure calculation unit 102 receives the calculated pressure from the vapor pressure extraction unit 101, it calculates a target pressure for adjusting the pressure inside the processing container 10 based on the calculated pressure. The target pressure is preferably calculated in consideration of the etching rate in the cleaning process.

[0055] FIG. 7 is a graph showing the relationship between the pressure in the processing vessel 10 and the etching rate when the detection temperature of the cleaning process is 32°C. In the graph shown in FIG. 7, the horizontal axis represents the pressure in the processing vessel 10, and the vertical axis represents the etching rate. The solid line in FIG. 7 indicates the etching rate at the position Z1 (see FIG. 2) of the top plate of the wafer boat 16. The one-dot chain line in FIG. 7 indicates the etching rate at the uppermost position Z2 (see FIG. 2) of the small fins 29 of the heat insulating unit 27. The two-dot chain line in FIG. 7 indicates the etching rate at the uppermost position Z3 (see FIG. 2) of the large fins 28 of the heat insulating unit 27. The thick one-dot chain line in FIG. 7 indicates the etching rate at the lowermost position Z4 (see FIG. 2) of the large fins 28 of the heat insulating unit 27. The thick two-dot chain line in FIG. 7 indicates the etching rate at the position Z5 (see FIG. 2) of the lid body 21.

[0056] As shown in FIG. 7, in the cleaning process, it can be seen that the etching rate increases as the pressure in the processing vessel 10 increases. However, it can be seen that as the pressure in the processing vessel 10 increases, the etching rates at the respective positions Z1 to Z5 tend to deviate from each other.

[0057] Specifically, looking at the etching rate at a pressure of 40 [Torr] (≈5332.89 [Pa]) in the graph of FIG. 7, there is a large deviation in the etching rate between the respective positions Z1 to Z5 (for example, the difference between the maximum value and the minimum value of the etching rate is more than 40 [nm / min] apart). Also, looking at the etching rate at a pressure of 35 [Torr] (≈4666.28 [Pa]), there is a deviation in the etching rate between the respective positions Z1 to Z5. That is, the processing vessel 10 corresponds to a region where the temperature is likely to decrease and a large amount of water is likely to be present in the lower part in the vertical direction (near the heat insulating unit 27). Therefore, the etching rate tends to increase toward the lower part in the vertical direction. In particular, it can be seen that the position Z5 on the upper surface of the lid body 21 is most likely to have the lowest temperature in the processing vessel 10, and liquid water is generated and etching is likely to proceed.

[0058] On the one hand, looking at the etching rate at a pressure of 30 [Torr] (≈ 3999.67 [Pa]) in the graph of FIG. 7, although the position Z1 is slightly lower, it can be said that the etching rates at positions Z2 to Z5 are generally consistent. That is, if the pressure in the processing chamber 10 is around 30 [Torr], uniform etching can proceed. Also, at a pressure of 20 [Torr] (≈ 2666.45 [Pa]), the etching rates at each position Z1 to Z5 are approximately the same, but it can be seen that the etching rate itself is low.

[0059] From the above, when calculating the target pressure, the pressure calculation unit 102 calculates a pressure such that the etching rate is high to some extent while prioritizing the uniformity of the etching rate. For this reason, the pressure calculation unit 102 may calculate the target pressure to be a value slightly lower than the vapor pressure curve 200.

[0060] The method for calculating the target pressure is not particularly limited. For example, a predetermined subtraction value Sv may be subtracted from the calculated pressure (vapor pressure). The subtraction value Sv may be stored in advance in the calculation storage unit 102a by conducting experiments using the processing chamber 10 of the same shape. The subtraction value Sv is set to a value such that the difference between the maximum value and the minimum value of the etching rates at each of the positions Z1 to Z5 set in the processing chamber 10 is 20 [nm / min] or less in the cleaning process. For example, when the detected temperature is 32 °C, as shown in FIG. 7, when the pressure in the processing chamber 10 is 35 [Torr], the difference between the etching rate at position Z5 (maximum value) and the etching rate at position Z1 (minimum value) is greater than 20 [nm / min]. On the other hand, when it is 33 [Torr] (≈ 4399.64 [Pa]) or less, the difference between the etching rate at position Z5 and the etching rate at position Z1 is 20 [nm / min] or less. Therefore, the subtraction value Sv may be set to a value greater than 2.7 [Torr] so that the target pressure is 33 [Torr] or less.

[0061] Note that the control unit 90 may have map information associating the pressure of the processing vessel 10 with the etching rate for each of a plurality of detected temperatures, and may refer to the map information corresponding to the detected temperature when the detected temperature is acquired. That is, the control unit 90 can set a target pressure at which the difference between the maximum value and the minimum value of the etching rate is 20 [nm / min] or less and etching non-uniformity can be suppressed, based on the map information.

[0062] Also, when aiming to achieve both suppression of etching non-uniformity and ensuring of the etching rate, the subtraction value Sv is more preferably set to a value in the range of 1 [Torr] to 10 [Torr]. As an example, in FIG. 7, the pressure calculation unit 102 stores 5.7 [Torr] (≈759.937 [Pa]) in advance as the subtraction value Sv, and subtracts 5.7 [Torr] when the pressure for calculation is acquired.

[0063] As shown in FIG. 3, the vapor pressures (pressures for calculation) of the respective devices A to E vary according to the detected temperature. The pressure calculation unit 102 can obtain a target pressure by subtracting the same subtraction value Sv (for example, 5.7 [Torr]) from the pressure for calculation corresponding to the detected temperature. Also, in FIG. 3, the pressure calculation unit 102 performs a process of rounding off the decimal part of the target pressure after subtracting the subtraction value Sv from the pressure for calculation. Thereby, the target pressure can be set to a natural number, and the pressure control by the exhaust unit 40 can be simplified.

[0064] Alternatively, the subtraction value Sv may be a variable value rather than a fixed value, or may be configured by the user of the processing device 1. For example, when the detected temperature is high, a large subtraction value Sv may be set, while when the detected temperature is low, a small subtraction value Sv may be set. Further, the subtraction value Sv may vary based on the cleaning processing time set according to a recipe or the like. For example, when the cleaning processing time is set long, a large subtraction value Sv may be set to make the target pressure sufficiently lower than the vapor pressure curve 200, so as to prioritize suppressing the etching unevenness of the deposited film. Conversely, when the cleaning processing time is set short, a small subtraction value Sv may be set to set the target pressure close to the vapor pressure curve 200, so that the processing efficiency can be prioritized.

[0065] Note that the target pressure may use the vapor pressure (i.e., the pressure of the gas-liquid equilibrium) overlapping the vapor pressure curve 200. In this case, the pressure calculation unit 102 will set the extracted vapor pressure as the target pressure without subtracting it. Thereby, the processing device 1 can further shorten the cleaning processing period. In other words, the control unit 90 may set the target pressure below the vapor pressure curve 200 by appropriately considering the etching uniformity and the etching rate.

[0066] The pressure control unit 103 adjusts the opening degree of the pressure adjustment valve 43 of the exhaust unit 40 based on the target pressure calculated by the pressure calculation unit 102. Further, the gas supply control unit 104 controls each component of the gas supply unit 30 (such as the flow regulator and the on-off valve installed in the gas nozzle 32) to adjust the supply amount of the cleaning gas containing fluorine into the processing chamber 10. Thereby, the pressure inside the processing chamber 10 of the processing device 1 is adjusted to the target pressure, and it becomes possible to stably perform the cleaning process.

[0067] The processing device 1 of the present disclosure is basically configured as described above, and the following operations (cleaning processing method) in the cleaning process will be described with reference to FIG. 8. FIG. 8 is a flowchart showing an example of the cleaning processing method.

[0068] When the processing device 1 is started up, started and stopped, or at an appropriate timing such as between one substrate process and another substrate process, the control unit 90 performs a cleaning process. As a preparation stage of the cleaning process, the control unit 90 raises the elevating mechanism 25 to seal the processing container 10 with the lid body 21 in a state where a dummy wafer is accommodated in the wafer boat 16 or in a state where the wafer boat 16 is empty. Note that the processing device 1 may perform the cleaning process in a state where the wafer boat 16 does not exist in the processing container 10.

[0069] Also, as described above, the control unit 90 stops the operation of the heating unit 50. Thereby, the temperature of the processing container 10 changes due to the influence of the surrounding environment of the processing device 1.

[0070] Therefore, in this cleaning process method, the temperature acquisition unit 100 of the control unit 90 detects the temperature inside the processing container 10 with the temperature sensor 70 and acquires the detected temperature from the temperature sensor 70 (step S1). At this time, the temperature sensor 70 detects the temperature of each zone with each temperature measuring element 71 to 75 and transmits it to the control unit 90. Thereby, the temperature acquisition unit 100 stores the temperature of each zone in the memory 92 and outputs one detected temperature to the vapor pressure extraction unit 101 based on a predetermined selection method or calculation method.

[0071] Also, the gas supply control unit 104 of the control unit 90 controls the gas supply unit 30 to supply a cleaning gas such as HF into the processing container 10 through the gas nozzle 32 (step S2).

[0072] The vapor pressure extraction unit 101 of the control unit 90 refers to the vapor pressure curve 200 stored in the vapor pressure curve storage unit 101a and extracts the vapor pressure corresponding to the detected temperature received from the temperature acquisition unit 100 (step S3). Then, the vapor pressure extraction unit 101 outputs the extracted vapor pressure to the pressure calculation unit 102 as the calculated pressure.

[0073] Furthermore, the pressure calculation unit 102 calculates the target pressure of the processing container 10 using the pressure for calculation input from the vapor pressure extraction unit (step S4). For example, as shown in FIG. 7, the pressure calculation unit 102 calculates the target pressure by subtracting a subtraction value Sv of 5.7 [Torr] from the pressure for calculation. The pressure calculation unit 102 outputs the calculated target pressure to the pressure control unit 103.

[0074] Based on the target pressure input from the pressure calculation unit 102, the pressure control unit 103 controls the operations of the pressure adjustment valve 43 and the vacuum pump 44 in the exhaust unit 40 to adjust the pressure in the processing container 10 to the target pressure (step S5). Further, the gas supply control unit 104 of the control unit 90 may control the gas supply unit 30 based on the target pressure to adjust the supply amount of the cleaning gas. Thereby, the pressure in the processing container 10 during the cleaning process is maintained at the target pressure. Therefore, the water generated in the processing container 10 exists as water vapor without condensing.

[0075] That is, in the processing container 10, the reactions of reaction formulas (1) to (3) can be promoted while maintaining water vapor. As a result, it is possible to suppress the etching unevenness of each component in the processing container 10. In addition, if the processing apparatus 1 sets a target pressure close to the vapor pressure, the etching rate of the cleaning process can be ensured to a certain extent, so that a decrease in work efficiency can be suppressed.

[0076] Note that it is preferable that the control unit 90 continuously repeats the above processing flow during the cleaning process. Thereby, even if the temperature in the processing container 10 changes, it is possible to immediately adjust to an appropriate target pressure and stably maintain the water vapor in the processing container 10. Alternatively, when the control unit 90 sets the target pressure by the above processing flow at the start of the cleaning process, the control unit 90 may maintain the target pressure during the cleaning process. Thereby, the processing apparatus 1 can suppress the target pressure from fluctuating in a short period and stabilize the processing.

[0077] The technical idea and effects of the present disclosure described in the above embodiments will be described below.

[0078] A first aspect of the present disclosure is a processing apparatus 1 including a processing container 10, a temperature sensor 70 that detects the temperature inside the processing container 10, a gas supply unit 30 that supplies a cleaning gas containing fluorine into the processing container 10, a pressure adjustment unit (gas supply unit 30, pressure adjustment valve 43) that adjusts the pressure inside the processing container 10, and a control unit 90 that controls the gas supply unit 30 and the pressure adjustment unit to perform a cleaning process for removing a deposited film inside the processing container 10. The control unit 90 stores a vapor pressure curve 200 associating the temperature inside the processing container 10 with the vapor pressure of water inside the processing container 10 in a storage unit (vapor pressure curve storage unit 101a). Further, in the cleaning process, the control unit 90 refers to the storage unit and sets a target pressure below the vapor pressure curve 200 based on the detected temperature detected by the temperature sensor 70 and the vapor pressure curve 200, and controls the pressure adjustment unit so that the pressure inside the processing container 10 becomes the target pressure.

[0079] According to the above, the processing apparatus 1 sets a target pressure below the vapor pressure curve 200 based on the detected temperature of the temperature sensor 70, and adjusts the inside of the processing container 10 to the target pressure, thereby suppressing the condensation of water inside the processing container 10 in the cleaning process. As a result, the processing apparatus 1 can suppress etching unevenness caused by the fluorine-containing gas and water, and can stably perform the cleaning process. For example, the processing apparatus 1 can effectively suppress damage to the configuration inside the processing container 10.

[0080] Further, the control unit 90 refers to the storage unit (vapor pressure curve storage unit 101a), extracts a vapor pressure corresponding to the detected temperature based on the vapor pressure curve 200, and calculates a target pressure by subtracting a subtraction value Sv from the extracted vapor pressure. Thereby, the processing apparatus 1 can easily obtain a target pressure corresponding to the detected temperature.

[0081] Further, the subtraction value Sv is a value such that the difference between the maximum value and the minimum value of the etching rate at each of a plurality of predetermined positions (positions Z1 to Z5) set in the processing container 10 in the cleaning process is 20 [nm / min] or less. Thereby, the processing apparatus 1 can perform etching in the processing container 10 more uniformly.

[0082] Further, the subtraction value Sv is set to a value in the range of 1 [Torr] to 10 [Torr]. Thereby, the processing apparatus 1 can secure the etching rate of the processing container 10 while suppressing etching unevenness, and can improve the efficiency of the processing.

[0083] Further, the subtraction value Sv is a variable value that varies according to the extracted vapor pressure or the processing time of the cleaning process. Thereby, the processing apparatus 1 can perform the processing at an appropriate target pressure according to the situation of the cleaning process.

[0084] Further, the control unit 90 sets the vapor pressure corresponding to the detected temperature as the target pressure with reference to the vapor pressure curve 200. Thereby, the processing apparatus 1 can set a high target pressure in the cleaning process, and can shorten the period of the cleaning process.

[0085] Further, the temperature sensor 70 detects the temperature for each of a plurality of zones in the processing container 10, and the control unit 90 sets any one of the average value, the maximum value, the minimum value, or the median value as the detected temperature based on the temperature for each of the plurality of zones acquired from the temperature sensor 70. Thereby, the processing apparatus 1 can accurately obtain the target pressure following the temperature in the processing container 10.

[0086] Further, the processing container 10 performs substrate processing for forming a silicon oxide film on the substrate W, and in the cleaning process, removes the silicon oxide film as the deposited film deposited in the processing container 10. Thereby, the processing apparatus 1 can stably etch the deposited film of the silicon oxide film in the processing container 10.

[0087] Further, a second aspect of the present disclosure is a cleaning method for removing a deposited film in the processing chamber 10, including: a step of acquiring the temperature in the processing chamber 10; a step of supplying a cleaning gas containing fluorine into the processing chamber 10; a step of setting a target pressure below the vapor pressure curve 200 based on the detected temperature detected in the temperature detection step and the vapor pressure curve 200 associating the temperature in the processing chamber 10 and the vapor pressure of water in the processing chamber 10; and a step of adjusting the pressure in the processing chamber 10 so that the pressure in the processing chamber 10 becomes the target pressure. Thereby, the cleaning method can perform the cleaning process more stably.

[0088] The processing apparatus 1 according to the embodiment disclosed this time is illustrative in all respects and not restrictive. The embodiment can be modified and improved in various forms without departing from the scope and gist of the appended claims. Matters described in the above plurality of embodiments can also adopt other configurations and can be combined within a non - conflicting range.

[0089] The processing apparatus 1 of the present disclosure is not limited to a vertical processing apparatus that processes a plurality of substrates W simultaneously, and may be a horizontal processing apparatus, or can also be applied to cleaning processes such as a single - wafer apparatus that processes the substrates W one by one. Further, for example, the processing apparatus 1 can be applied to any type of apparatus such as an Atomic Layer Deposition (ALD) apparatus, a Capacitively Coupled Plasma (CCP), an Inductively Coupled Plasma (ICP), a Radial Line Slot Antenna (RLSA), an Electron Cyclotron Resonance Plasma (ECR), and a Helicon Wave Plasma (HWP).

Description of Reference Numerals

[0090] 1 Processing apparatus 10 Processing chamber 30 Gas supply unit 43 Pressure regulating valve 70 Temperature sensor 90 Control Unit 200 Vapor Pressure Curve

Claims

1. A processing container, a temperature sensor for detecting the temperature inside the processing container, a gas supply unit for supplying a cleaning gas containing fluorine into the processing container, a pressure adjustment unit for adjusting the pressure inside the processing container, and a control unit for controlling the gas supply unit and the pressure adjustment unit to perform a cleaning process for removing a deposited film inside the processing container, wherein the control unit stores a vapor pressure curve associating the temperature inside the processing container with the vapor pressure of water inside the processing container in a storage unit, and in the cleaning process, the control unit refers to the storage unit, sets a target pressure below the vapor pressure curve based on the detected temperature detected by the temperature sensor and the vapor pressure curve, and controls the pressure adjustment unit so that the pressure inside the processing container becomes the target pressure. A processing apparatus.

2. The control unit refers to the storage unit, extracts a vapor pressure corresponding to the detected temperature based on the vapor pressure curve, and calculates the target pressure by subtracting a subtraction value from the extracted vapor pressure. The processing apparatus according to claim 1.

3. The subtraction value is a value such that the difference between the maximum value and the minimum value of the etching rate at a plurality of predetermined positions set inside the processing container in the cleaning process is 20 [nm / min] or less. The processing apparatus according to claim 2.

4. The subtraction value is set to a value in the range of 1 [Torr] to 10 [Torr]. The processing apparatus according to claim 2 or 3.

5. The subtraction value is a variable value that varies according to the extracted vapor pressure or the processing time of the cleaning process. The processing apparatus according to any one of claims 2 to 4.

6. The control unit sets the vapor pressure corresponding to the detected temperature as the target pressure with reference to the vapor pressure curve. The processing apparatus according to claim 1.

7. The temperature sensor detects the temperature for each of a plurality of zones inside the processing container, and the control unit sets any one of an average value, a maximum value, a minimum value, or a median value as the detected temperature based on the temperature for each of the plurality of zones acquired from the temperature sensor. The processing apparatus according to any one of claims 1 to 6.

8. The processing container performs substrate processing for forming a silicon oxide film on a substrate, and in the cleaning process, the silicon oxide film is removed as the deposited film deposited inside the processing container. The processing apparatus according to any one of claims 1 to 7.

9. A cleaning method for removing a deposited film in a processing container, a step of obtaining the temperature inside the processing container, a step of supplying a cleaning gas containing fluorine into the processing container, a step of setting a target pressure below the vapor pressure curve based on the detected temperature detected in the step of detecting the temperature and a vapor pressure curve associating the temperature inside the processing container and the vapor pressure of water inside the processing container, and a step of adjusting the pressure inside the processing container so that the pressure inside the processing container becomes the target pressure. Cleaning method.

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