Substrate processing apparatus and substrate processing method

Abstract

The invention provides a substrate processing apparatus and a substrate processing method. The substrate processing apparatus includes a processing container, a pressure detection unit, a temperature detection unit, and a control unit. The processing container performs drying processing on the substrate in the processing container. The drying process includes a step of increasing the pressure in the processing container. The pressure detection unit detects the pressure of the processing fluid in the processing container. The temperature detection unit detects the temperature of the processing fluid in the processing container. The control unit includes: a first density calculation unit that calculates the density of the processing fluid on the basis of a first pressure and a first temperature detected in a pressure increasing step of a drying process executed in a state in which no drying liquid is present; a second density calculation unit that calculates the density of the processing fluid on the basis of a second pressure and a second temperature detected in a pressure increasing step of the drying processing performed in the presence of the drying liquid; a density difference calculation unit that calculates a density difference between the first density and the second density; and a suitability determination unit that determines, on the basis of the density difference, whether the liquid film state of the drying liquid is suitable.

Description

Technical Field

[0001] This invention relates to a substrate processing apparatus and a substrate processing method. Background Technology

[0002] Previously, supercritical drying processes were known to dry substrates by contacting a substrate with a surface wetted by a drying liquid with a supercritical processing fluid, thereby replacing the drying liquid with the processing fluid.

[0003] For example, the substrate processing apparatus described in Patent Document 1 includes: a pressure vessel capable of housing a substrate; a discharge line for discharging fluid from inside the pressure vessel; and a concentration measuring unit for measuring the concentration of the drying liquid in the fluid flowing in the discharge line. In this substrate processing apparatus, anomalies in the amount of the drying liquid film formed on the substrate are detected based on the concentration of the drying liquid measured by the concentration measuring unit.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-43882 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, the aforementioned prior art measures the concentration of the drying liquid in the fluid flowing in the discharge line, making it difficult to detect abnormalities in the liquid film when the discharge line is closed. Furthermore, the aforementioned prior art struggles to detect liquid film abnormalities before the process fluid is used to replace the drying liquid. Therefore, for example, in steps performed before the process fluid is used to replace the drying liquid, specifically during the pressurization process where the pressure in the pressure vessel is increased by supplying the process fluid to the pressure vessel with the discharge line closed, it is difficult to detect abnormalities in the liquid film state.

[0009] This invention provides a technique for detecting abnormalities in the liquid film state of the drying liquid during pressurization.

[0010] Means for solving technical problems

[0011] One aspect of the substrate processing apparatus of the present invention includes a processing container, a pressure detection unit, a temperature detection unit, and a control unit. The substrate is dried by supplying a processing fluid into the processing container, thereby replacing the liquid film of the drying liquid formed on the substrate with a supercritical processing fluid. The drying process includes a pressurization step of increasing the pressure inside the processing container to a set pressure above a critical pressure by supplying the processing fluid into the processing container. The pressure detection unit is capable of detecting the pressure of the processing fluid located inside the processing container. The temperature detection unit is capable of detecting the temperature of the processing fluid located inside the processing container. The control unit includes a first density calculation unit that, during the pressurization step of the pre-processing, calculates first density data representing the change in density of the processing fluid over time based on a first pressure detected by the pressure detection unit and a first temperature detected by the temperature detection unit, wherein the pre-processing is performed when no liquid film of the drying liquid has formed on the substrate. Furthermore, the control unit includes a second density calculation unit, which, during the pressurization step of the formal processing, calculates second density data representing the change in density of the processing fluid over time based on a second pressure detected by a pressure detection unit and a second temperature detected by a temperature detection unit. The formal processing is a drying process performed while a liquid film of the drying fluid is formed on the substrate. Additionally, the control unit includes a density difference calculation unit, which calculates density difference data, which is the difference between the first density data and the second density data. Furthermore, the control unit includes an suitability determination unit, which, based on the density difference data, determines whether the state of the liquid film of the drying fluid formed on the substrate is suitable during the formal processing.

[0012] Invention Effects

[0013] Using this invention, abnormalities in the liquid film state of the drying liquid can be detected during the pressurization process. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the substrate processing system of the first embodiment as viewed from above.

[0015] Figure 2 This is a schematic diagram of the substrate processing system of the first embodiment, viewed from the side.

[0016] Figure 3 This is a flowchart representing a series of substrate processing flows executed in the substrate processing system of the first embodiment.

[0017] Figure 4 This is a schematic diagram illustrating the wafer transport process.

[0018] Figure 5 This is a schematic diagram showing a structural example of the liquid treatment unit in the first embodiment.

[0019] Figure 6This is a schematic diagram showing a structural example of the drying unit in the first embodiment.

[0020] Figure 7 This is a schematic diagram showing an example of the piping structure of the drying unit in the first embodiment.

[0021] Figure 8 This is a flowchart illustrating the drying process performed in the substrate processing system of the first embodiment.

[0022] Figure 9 This is a schematic diagram used to illustrate the internal conditions of the processing container during the pressurization step.

[0023] Figure 10 This is a diagram showing a structural example of the control device of the first embodiment, represented by function blocks.

[0024] Figure 11 This is a graph illustrating an example of the relationship between density, pressure, and temperature in a supercritical fluid.

[0025] Figure 12 This is a diagram representing an example of first-density data.

[0026] Figure 13 This is a diagram representing an example of second-density data.

[0027] Figure 14 This is a graph representing an example of density difference data.

[0028] Figure 15 This is a diagram showing an example of data stored in the storage unit of the first embodiment.

[0029] Figure 16 This is a flowchart illustrating a series of anomaly detection processes performed in the control unit of the first embodiment.

[0030] Figure 17 This is a graph representing an example of density difference data that includes anomalies from the drying process.

[0031] Figure 18 This is a flowchart illustrating the process of determining suitability in the suitability determination unit of the first embodiment.

[0032] Figure 19 This is a diagram showing a structural example of the control device of the second embodiment, represented by function blocks.

[0033] Figure 20 This is a flowchart illustrating a series of anomaly detection processes performed in the control unit of the second embodiment.

[0034] Figure 21This is a flowchart illustrating the prediction and judgment process performed in the prediction and judgment unit of the second embodiment.

[0035] Explanation of reference numerals in the attached figures

[0036] 1. Substrate processing system; TS1, TS2, TS3, TS4 temperature sensors; PS1, PS2, PS3 pressure sensors; 4. Drying unit; 7. Control device; 41. Processing container; 71. Control unit; 72. Storage unit; 73. First density calculation unit; 74. Second density calculation unit; 75. Density difference calculation unit; 76. Appropriateness judgment unit; 77. Adjustment unit; 78. Prediction judgment unit; D1. First density data; D2. Second density data; ΔD. Density difference data; P A First pressure, P B The second pressure, T A Temperature 1, T B Second temperature, W wafer. Detailed Implementation

[0037] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of the embodiments (hereinafter referred to as "Embodiments") for carrying out the substrate processing apparatus and substrate processing method of the present invention. However, the present invention is not limited to these embodiments. Furthermore, the various embodiments can be appropriately combined without contradicting the processing content. In the following embodiments, the same reference numerals are used to label the same parts, and repeated descriptions are omitted.

[0038] In addition, in the various figures referred to below, for the sake of clarity, an orthogonal coordinate system is sometimes shown, which specifies that the X-axis, Y-axis and Z-axis are orthogonal to each other, with the Z-axis being the vertically upward direction.

[0039] <Structure of the Substrate Processing System>

[0040] First, refer to Figure 1 and Figure 2 The structure of the substrate processing system (an example of a substrate processing apparatus) of this embodiment will be described. Figure 1 This is a schematic diagram of the substrate processing system of the first embodiment, viewed from above. Additionally, Figure 2 This is a schematic diagram of the substrate processing system of the first embodiment, viewed from the side.

[0041] like Figure 1 As shown, the substrate processing system 1 includes an input / output station 11 and a processing station 12. The input / output station 11 and the processing station 12 are arranged adjacent to each other.

[0042] The infeed / outfeed station 11 includes a carrier placement section 111 and a transport section 112. Multiple carriers C can be placed in the carrier placement section 111, and the carriers C can hold multiple semiconductor wafers W (hereinafter referred to as "wafers W") in a horizontal state.

[0043] The conveying section 112 is disposed adjacent to the carrier placement section 111. The conveying device 113 and the transfer section 114 are disposed inside the conveying section 112.

[0044] The transport device 113 includes a wafer holding mechanism capable of holding the wafer W. Furthermore, the transport device 113 is capable of horizontal and vertical movement and rotation about a vertical axis, and can transport the wafer W between the carrier C and the junction 114 using the wafer holding mechanism.

[0045] The junction 114 can temporarily hold the chip W.

[0046] The processing station 12 is disposed adjacent to the conveying unit 112. The processing station 12 includes a conveying block 13, a first processing block 14, and a second processing block 15.

[0047] The conveying block 13 includes a conveying area 131 and a conveying device 132. The conveying area 131 is, for example, a cuboid-shaped area extending along the arrangement direction (X-axis direction) of the feed-in / feed-out station 11 and the processing station 12. The conveying device 132 is arranged in the conveying area 131.

[0048] The transport device 132 includes a wafer holding mechanism 132a capable of holding the wafer W. In addition, the transport device 132 is capable of horizontal and vertical movement and rotation about the vertical axis, and can transport the wafer W between the junction 114, the first processing block 14 and the second processing block 15 using the wafer holding mechanism 132a.

[0049] The first processing block 14 and the second processing block 15 are arranged adjacent to the conveying area 131 on both sides of the conveying area 131. As an example, the first processing block 14 is arranged on one side (positive Y-axis side) of the conveying area 131 in a direction orthogonal to the arrangement direction (X-axis direction) of the infeed / outfeed station 11 and the processing station 12. The second processing block 15 is arranged on the other side (negative Y-axis side) of the conveying area 131 in a direction orthogonal to the arrangement direction (X-axis direction) of the infeed / outfeed station 11 and the processing station 12.

[0050] Alternatively, it could be as follows: Figure 2As shown, a plurality of first processing blocks 14 and a plurality of second processing blocks 15 are arranged in multiple layers along the vertical direction. In the first embodiment, the number of layers of the plurality of first processing blocks 14 and the plurality of second processing blocks 15 is 3, but the number of layers of the plurality of first processing blocks 14 and the plurality of second processing blocks 15 is not limited to 3.

[0051] As described above, in the substrate processing system 1 of the embodiment, a plurality of first processing blocks 14 and a plurality of second processing blocks 15 can be arranged on multiple layers on both sides of the transport block 13. Moreover, the transport of the wafer W between the first processing blocks 14 and second processing blocks 15 arranged on each layer and the junction 114 can be performed by a transport device 132 arranged on the transport block 13.

[0052] The first processing block 14 includes multiple liquid processing units 2.

[0053] The liquid processing unit 2 is capable of cleaning the upper surface of the wafer W, which serves as the patterning surface. Additionally, the liquid processing unit 2 is capable of liquid film formation by supplying IPA (isopropanol) liquid (an example of a drying solution) to the upper surface of the cleaned wafer W to form a liquid film. The structure of the liquid processing unit 2 will be described in reference to... Figure 5 This will be explained later.

[0054] The second processing block 15 includes multiple measuring units 3, multiple drying units 4, and multiple supply units 6.

[0055] The measuring unit 3 is capable of measuring the weight of the wafer W. Specifically, the measuring unit 3 is capable of measuring the weight of the wafer W before and after the liquid film formation process. In the first embodiment, the measuring unit 3 is disposed on the upper part of the drying unit 4 (see reference 4). Figure 2 ).

[0056] Drying unit 4 is capable of performing supercritical drying (hereinafter referred to as "drying treatment") on the wafer W after liquid film formation treatment. Specifically, drying unit 4 dries the wafer W by contacting it with a supercritical processing fluid. The structure of drying unit 4 will be described in reference to... Figure 6 This will be explained later. Furthermore, the supercritical fluid being processed will sometimes be referred to as a supercritical fluid in the following explanation.

[0057] The supply unit 6 is capable of supplying processing fluid to the drying unit 4. Specifically, the supply unit 6 includes: a supply device assembly including a flow meter, a flow regulator, a back pressure valve, a heater, etc.; and a housing capable of housing the supply device assembly. In this embodiment, the supply unit 6 is capable of supplying CO2 as a processing fluid to the drying unit 4.

[0058] In addition, such as Figure 2As shown, the measuring unit 3 and the drying unit 4 are arranged overlapping in the vertical direction. As an example, the measuring unit 3 is arranged overlapping on top of the drying unit 4. Alternatively, the measuring unit 3 may be arranged overlapping below the drying unit 4. By arranging the measuring unit 3 and the drying unit 4 overlapping in the vertical direction, the installation area of ​​the second processing block 15 can be reduced.

[0059] The substrate processing system 1 includes a control device 7. The control device 7 is, for example, a computer, including a control unit 71 and a storage unit 72.

[0060] The control unit 71 includes a microcomputer with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), input / output ports, and various circuits. The CPU of this microcomputer can read and execute programs stored in the ROM to control the conveying devices 113 and 132, the liquid treatment unit 2, the drying unit 4, and the supply unit 6.

[0061] Alternatively, the program can be recorded on a computer-readable recording medium and installed from that recording medium into the storage unit 72 of the control device 7. Examples of computer-readable recording media include hard disks (HD), floppy disks (FD), optical disks (CD), magneto-optical disks (MO), and memory cards.

[0062] The storage unit 72 is implemented, for example, by semiconductor memory elements such as RAM and flash memory, or storage devices such as hard disks and optical disks.

[0063] <Substrate Processing Flow>

[0064] Next, refer to Figure 3 and Figure 4 The transport process of the wafer W and a series of substrate processing processes in the substrate processing system 1 described above will be explained. Figure 3 This is a flowchart illustrating a series of substrate processing flows executed in the substrate processing system 1 of the first embodiment. Figure 4 This is a schematic diagram illustrating the transport process of wafer W. Furthermore, Figure 3 The series of substrate processing shown is executed under the control of the control unit 71.

[0065] like Figure 3 As shown, in the substrate processing system 1, the first step is the feeding process (step S101). During the feeding process, the transport device 113 (refer to...) Figure 1 Remove the wafer W from the carrier C and place it on the junction 114 (see reference). Figure 4 Process S1).

[0066] Next, the conveyor 132 (refer to...) Figure 1 The wafer W is removed from the transfer section 114 and sent to the liquid processing unit 2 (see reference). Figure 4 Process S2).

[0067] Next, in the substrate processing system 1, a cleaning process is performed in the liquid processing unit 2 (step S102). The liquid processing unit 2 removes particles and native oxide films from the upper surface of the wafer W by supplying various processing liquids to the upper surface of the wafer W, which serves as the patterning surface.

[0068] Next, in the substrate processing system 1, a liquid film formation process is performed in the liquid processing unit 2 (step S103). The liquid processing unit 2 forms a liquid film of IPA on the upper surface of the wafer W by supplying liquid IPA to the upper surface of the cleaned wafer W.

[0069] In addition, although Figure 3 and Figure 4 Illustrations are omitted, but for example, the weight measurement of the wafer W performed by the measuring unit 3 can be performed before and after the liquid film formation process in step S103. This will be discussed in more detail in [reference needed]. Figure 6 This will be explained later. In this case, the wafer W can be transported by the transport device 132 (see reference 132). Figure 1 Appropriately fed into and out relative to measurement unit 3.

[0070] After liquid film formation, the wafer W is transported from the liquid treatment unit 2 to the drying unit 4 by the transport device 132. Figure 4 Process S3).

[0071] Next, in the substrate processing system 1, a drying process begins in the drying unit 4 (step S104). During the drying process, the drying unit 4 dries the wafer W by bringing the wafer W, after liquid film formation, into contact with a supercritical processing fluid. The control unit 71, for example, ends the drying process after a preset drying time has elapsed.

[0072] Next, in the substrate processing system 1, a delivery process is performed (step S105). During the delivery process, the transport device 132 removes the dried wafer W from the drying unit 4 and transports it to the transfer unit 114 (see reference 114). Figure 4 (Process S4). Afterwards, the transport device 113 removes the dried wafer W from the transfer section 114 and transports it to the carrier C (see reference). Figure 4 (Flow S5). When the output processing is finished, the series of substrate processing for a wafer W ends.

[0073] <Structure of the liquid treatment unit>

[0074] Next, refer to Figure 5 The structure of liquid treatment unit 2 will be described. Figure 5 This is a schematic diagram showing a structural example of the liquid processing unit 2 in the first embodiment. The liquid processing unit 2 is configured, for example, as a monolithic cleaning device capable of cleaning wafers W one by one by rotating them.

[0075] like Figure 5 As shown, the liquid treatment unit 2 can hold the wafer W in a substantially horizontal position using the wafer holding mechanism 23 disposed within the outer chamber 21 forming the processing space, and rotate the wafer W by rotating the wafer holding mechanism 23 about a vertical axis. The liquid treatment unit 2 can bring the nozzle arm 24 above the rotating wafer W, and supply liquid and rinsing liquid from the liquid nozzle 24a disposed at the front end of the nozzle arm 24 in a predetermined sequence, thereby performing cleaning treatment on the upper surface of the wafer W.

[0076] Furthermore, in the liquid processing unit 2, a liquid supply path 23a is also formed inside the wafer holding mechanism 23. The lower surface of the wafer W can be cleaned using the liquid and rinsing solution supplied from this liquid supply path 23a.

[0077] The cleaning process involves, for example, first removing particulate and organic contaminants using SC1 solution (a mixture of ammonia and hydrogen peroxide), which is alkaline; then rinsing with deionized water (hereinafter referred to as "DIW"). Next, removing the natural oxide film using a dilute hydrofluoric acid solution (hereinafter referred to as "DHF"), which is acidic, followed by rinsing with DIW.

[0078] The various medicinal solutions described above can be received by the outer chamber 21 or the inner cup 22 disposed within the outer chamber 21, and discharged from the drain port 21a at the bottom of the outer chamber 21 or the drain port 22a at the bottom of the inner cup 22. Furthermore, the atmosphere inside the outer chamber 21 can be vented from the vent port 21b at the bottom of the outer chamber 21.

[0079] The liquid film formation process is performed after the rinsing process in the cleaning process. Specifically, the liquid treatment unit 2 can supply IPA to the upper and lower surfaces of the wafer W while rotating the wafer holding mechanism 23. As a result, the DIW remaining on both sides of the wafer W can be replaced with IPA. Afterward, the liquid treatment unit 2 slowly stops the rotation of the wafer holding mechanism 23.

[0080] After the liquid film formation process is completed, the wafer W, with an IPA liquid film formed on its upper surface, is transferred to the transport device 132 by a transfer mechanism (not shown) provided in the wafer holding mechanism 23, and is then sent out from the liquid processing unit 2. The liquid film formed on the wafer W can prevent pattern collapse due to liquid evaporation (vaporization) on the upper surface of the wafer W during the transport of the wafer W from the liquid processing unit 2 to the drying unit 4, or during the feeding operation.

[0081] <Structure of the drying unit>

[0082] Next, refer to Figure 6 and Figure 7 The structure of drying unit 4 will be described. Figure 6 This is a schematic diagram showing a structural example of the drying unit 4 in the first embodiment. Figure 7 This is a schematic diagram showing an example of the piping structure of the drying unit 4 in the first embodiment.

[0083] Drying unit 4 is capable of performing the drying process described above. Drying unit 4 dries wafer W by replacing the liquid film of IPA formed on wafer W with a supercritical processing fluid (supercritical fluid). A supercritical fluid is a fluid whose liquid and gas states cannot be distinguished at temperatures above a critical temperature and pressure above a critical pressure. When IPA is replaced with a supercritical fluid, the appearance of a liquid-gas interface on the uneven pattern of wafer W can be suppressed. As a result, the generation of surface tension can be suppressed, and the collapse of the uneven pattern can be prevented. A supercritical fluid is, for example, CO2.

[0084] like Figure 6 As shown, the drying unit 4 includes a processing container 41, a holding portion 42, and a cover 43. The processing container 41 is capable of housing a wafer W with an IPA liquid film formed thereon. The processing container 41 has an opening 44 for feeding and discharging the wafer W; supply ports 45A and 45B for connecting to the supply line L1 described later; and a discharge port 46 for connecting to the discharge line L2 described later.

[0085] A temperature sensor TS4 (an example of a temperature detection unit) is provided on the side of the processing container 41. The temperature sensor TS4 is capable of detecting the temperature of the processing fluid located inside the processing container 41. The detected temperature information is output to the control unit 71.

[0086] Furthermore, in the first embodiment, only one temperature sensor TS4 is provided on the side of the processing container 41, but multiple temperature sensors may also be provided on the processing container 41. These multiple temperature sensors may be provided, for example, on a side different from the side where the temperature sensor TS4 is provided, or on the upper surface of the processing container 41. In this case, the average value of the multiple temperature sensors can be detected as the temperature of the processed fluid.

[0087] The holding part 42 is capable of holding the wafer W in a horizontal position. The holding part 42 is, for example, a rectangular frame when viewed from above, capable of holding the wafer W by supporting its outer periphery from below. The holding part 42 can be raised and lowered by a lifting device (not shown) provided in the cover 43 (described later). According to this structure, by raising and lowering the wafer W inside the processing container 41, the gap between the upper surface of the processing container 41 and the liquid film of IPA formed on the upper surface of the wafer W can be adjusted.

[0088] The cover 43 supports the holding portion 42. The cover 43 has a lifting device (not shown) for raising and lowering the holding portion 42 as described above. Furthermore, the cover 43 is connected to a moving mechanism (not shown), which allows it to move horizontally between a "processing position" located inside the processing container and a "first handover position" located outside the processing container, where the wafer W can be transferred between the transport device 132 and the holding portion 42. By moving the cover 43 to the processing position, the holding portion 42 is positioned inside the processing container 41, and the cover 43 closes the opening 44 of the processing container 41.

[0089] Here, the structure of measuring unit 3 will be described. For example... Figure 6 As shown, in the first embodiment, the measuring unit 3 is disposed on top of the drying unit 4. The measuring unit 3 includes, for example, a housing 31, a weight sensor 32, and a support member 33. An opening 31a is formed in the housing 31 for the wafer W to be fed in and out by the conveying device 132.

[0090] The weight sensor 32 is capable of horizontally supporting the wafer W to measure its weight. As described above, the weight sensor 32 can, for example, measure the weight of the wafer W before and after the liquid film formation process performed by the liquid processing unit 2. That is, the weight sensor 32 measures the weight of the wafer W without an IPA liquid film and the weight of the wafer W with an IPA liquid film. The control unit 71 can use the measurement value of the weight sensor 32 to calculate the amount of liquid film of the IPA formed in the liquid film formation process.

[0091] The support member 33 is arranged to stand upright from the bottom of the housing 31, supporting the weight sensor 32 from below. In addition, the measuring unit 3, which includes the weight sensor 32 and the support member 33, is provided for example for multiple drying units 4, and is capable of measuring the weight of the wafer W transported to each drying unit 4.

[0092] Supply port 45A is connected to the side opposite to the opening 44 of processing container 41. Additionally, supply port 45B is connected to the bottom surface of processing container 41. Furthermore, discharge port 46 is connected to the lower side of opening 44. Figure 6 andFigure 7 The diagram shows two supply ports 45A and 45B and one discharge port 46, but the number and location of the supply ports 45A and 45B and the discharge port 46 are not specifically limited.

[0093] Additionally, a supply head 451A, 451B and a discharge head 461 are provided inside the processing container 41. Multiple openings (not shown) are formed in each of the supply head 451A, 451B and the discharge head 461.

[0094] The supply head 451A is connected to the supply port 45A and is disposed adjacent to the side opposite to the opening 44 inside the processing container 41. In addition, a plurality of openings are formed in the supply head 451A, for example, facing the opening 44.

[0095] The supply head 451B is connected to the supply port 45B and is located in the center of the bottom surface inside the processing container 41. Additionally, multiple openings are formed in the supply head 451B, for example, facing upwards.

[0096] The discharge head 461 is connected to the discharge port 46, is located inside the processing container 41 adjacent to the side of the opening 44, and is positioned below the opening 44. Additionally, multiple openings are formed in the discharge head 461, for example, facing the supply head 451A.

[0097] The supply heads 451A and 451B can supply processing fluid into the interior of the processing container 41. In addition, the discharge head 461 can discharge the processing fluid and IPA from the interior of the processing container 41 to the outside.

[0098] like Figure 7 As shown, the drying unit 4 is connected to a supply line L1 and a discharge line L2. The supply line L1 supplies the processing fluid to the drying unit 4, and the discharge line L2 discharges the processing fluid and IPA from the drying unit 4. The supply line L1 connects the fluid supply source to the processing container 41. Processing fluid can be supplied from the fluid supply source to the supply line L1. A heater (not shown) is provided on the supply line L1. The heater is capable of maintaining the processing fluid supplied to the processing container 41 above a critical temperature. The heater is, for example, provided over the entire area of ​​the supply line L1.

[0099] Supply line L1 includes a common line L1a, a flow line L1b, and a booster line L1c. The upstream end of the common line L1a is connected to the fluid supply source, and the downstream end of the common line L1a is connected to the flow line L1b and the booster line L1c. The flow line L1b is connected to supply port 45A, and the booster line L1c is connected to supply port 45B.

[0100] An on / off valve 52a is installed in the flow line L1b. The on / off valve 52a can open and close the flow path of the fluid. When the on / off valve 52a opens the flow path, the processed fluid can pass through the supply port 45A and the supply head 451A (see reference). Figure 6 The fluid is supplied to the interior of the processing container 41. On the other hand, when the on / off valve 52a closes the flow path, the supply of processing fluid to the processing container 41 can be stopped.

[0101] Similarly, an on / off valve 52b, a pressure sensor PS1, and a temperature sensor TS1 are installed on the booster line L1c. The on / off valve 52b can open and close the fluid flow path. When the on / off valve 52b opens the flow path, the processed fluid can flow through the supply port 45B and the supply head 451B (see reference). Figure 6 The fluid is supplied to the interior of the processing container 41. Conversely, when the on / off valve 52b closes the flow path, the supply of processing fluid to the processing container 41 can be stopped. The pressure sensor PS1 can detect the pressure of the fluid flowing in the booster line L1c. The temperature sensor TS1 can detect the temperature of the fluid flowing in the booster line L1c.

[0102] Additionally, the booster line L1c is connected to the bypass line L3 downstream of the on / off valve 52b, pressure sensor PS1, and temperature sensor TS1. An on / off valve 52h is installed on the bypass line L3. The on / off valve 52h can open and close the flow path of the fluid. When the on / off valve 52h opens the flow path, a portion of the processing fluid flowing in the booster line L1c can be released to the discharge line L2 via the bypass line L3. This suppresses the supply flow rate of the processing fluid to the interior of the processing container 41.

[0103] In addition, the flow line L1b and the booster line L1c are provided separately in the first embodiment, but they can also be integrated.

[0104] The discharge pipeline L2 includes, for example, the on / off pipeline L2a, the first common pipeline L2c, the first intermediate pipeline L2d, the second intermediate pipeline L2e, the third intermediate pipeline L2f, and the second common pipeline L2g.

[0105] The on / off line L2a extends from the discharge port 46 of the processing container 41 to the upstream end of the first common line L2c. An on / off valve 52c, a pressure sensor PS2 (an example of a pressure detection unit), and a temperature sensor TS2 are installed on the on / off line L2a. The on / off valve 52c can open and close the flow path of the fluid. When the on / off valve 52c opens the flow path, the fluid inside the processing container 41 can pass through the discharge head 461 (see reference 42c). Figure 6 The fluid is discharged to the outside of the substrate processing system 1 through the discharge port 46. On the other hand, when the on / off valve 52c closes the flow path, the discharge of fluid from the processing container 41 can be stopped.

[0106] Pressure sensor PS2 can detect the pressure of the fluid flowing in the open / closed line L2a. This pressure sensor PS2 is positioned upstream of the open / closed valve 52c in the open / closed line L2a. Therefore, by closing the open / closed valve 52c, pressure sensor PS2 can detect the pressure of the processing fluid inside the processing container 41. The detected pressure information is output to the control unit 71. Additionally, temperature sensor TS2 can detect the temperature of the fluid flowing in the open / closed line L2a.

[0107] A pressure reducing valve 53, a flow meter 54, a pressure sensor PS3, and a temperature sensor TS3 are installed in the first common pipeline L2c. The pressure reducing valve 53 lowers the pressure of the fluid downstream of it than the pressure of the fluid upstream of it. The pressure upstream of the pressure reducing valve 53 is, for example, 4 MPa to 18 MPa, and the pressure downstream is, for example, 0.1 MPa to 0.5 MPa. The flow meter 54 measures the flow rate of the fluid before and after pressure reduction. The pressure sensor PS3 detects the pressure of the fluid flowing in the first common pipeline L2c. The temperature sensor TS3 detects the temperature of the fluid flowing in the first common pipeline L2c.

[0108] Furthermore, the downstream end of the bypass line L3 is connected to the upstream end of the first shared line L2c. Therefore, for example, by adjusting the opening degree of the pressure reducing valve 53 with the on / off valve 52c closed and the on / off valve 52h open, a portion of the processing fluid flowing in the boost line L1c can be discharged to the outside of the processing container 41. This allows for the regulation of the supply flow rate of the processing fluid supplied to the interior of the processing container 41.

[0109] Additionally, for example, by adjusting the opening degree of the pressure reducing valve 53 while the on / off valve 52c is open and the on / off valve 52h is closed, the discharge flow rate of the processing fluid discharged from the processing container 41 via the on / off line L2a can be adjusted.

[0110] The first intermediate pipeline L2d, the second intermediate pipeline L2e, and the third intermediate pipeline L2f extend from the downstream end of the first common pipeline L2c to the upstream end of the second common pipeline L2g, respectively.

[0111] A shut-off valve 52e, a check valve 55a, and a throttling orifice 56 are provided on the first intermediate pipeline L2d. The shut-off valve 52e can open and close the flow path of the fluid. When the shut-off valve 52e opens the flow path, the fluid inside the processing container 41 can be discharged to the outside of the substrate processing system 1 through the shut-off valve 52e. On the other hand, when the shut-off valve 52e closes the flow path, it can stop the discharge of fluid through the first intermediate pipeline L2d. The check valve 55a can prevent backflow of the fluid. The throttling orifice 56 can reduce the pressure of the processing fluid flowing in the downstream piping to a desired value.

[0112] Similarly, an on / off valve 52f and a check valve 55b are provided on the second intermediate pipeline L2e. The on / off valve 52f can open and close the flow path of the fluid. When the on / off valve 52f opens the flow path, the fluid inside the processing container 41 can be discharged to the outside of the substrate processing system 1 through the on / off valve 52f. On the other hand, when the on / off valve 52f closes the flow path, it can stop the discharge of fluid through the second intermediate pipeline L2e. The check valve 55b can prevent backflow of the fluid.

[0113] An on / off valve 52g is installed on the third intermediate pipeline L2f. The on / off valve 52g can open and close the flow path of the fluid. When the on / off valve 52g opens the flow path, the fluid inside the processing container 41 can be discharged to the outside of the substrate processing system 1 through the on / off valve 52g. On the other hand, when the on / off valve 52g closes the flow path, the discharge of fluid through the third intermediate pipeline L2f can be stopped.

[0114] Furthermore, the first intermediate pipeline L2d, the second intermediate pipeline L2e, and the third intermediate pipeline L2f are provided separately in this embodiment, but they can also be integrated. However, in the former case, the fluid discharge flow rate can be precisely controlled by discharging the fluid through multiple on / off valves 52e, 52f, and 52g.

[0115] <Drying Processing Method>

[0116] Next, refer to Figure 8 The drying process is explained. Figure 8 This is a flowchart illustrating the drying process performed in the substrate processing system 1 of the first embodiment. Figure 8 The steps S201 to S205 shown are performed under the control of the control unit 71.

[0117] First, in step S201, a conveying device (not shown) delivers a wafer W with an IPA liquid film formed on it into the drying unit 4. A holding unit 42 receives the wafer W from the conveying device and holds the wafer W horizontally with the IPA liquid film facing upwards. The wafer W is then housed inside a processing container 41, and a cover 43 closes the opening 44 of the processing container 41.

[0118] Next, in step S202, the supply line L1 supplies processing fluid to the interior of the processing container 41 via the supply port 45B and the supply head 451B, thereby increasing the internal pressure of the processing container 41. At this time, the processing fluid is supplied from below the wafer W in a manner that does not disturb the liquid film of the IPA formed on the wafer W. As a result, the pressure inside the processing container 41 can be increased to a set pressure above the critical pressure. Hereinafter, this step S202 will sometimes be described as the pressure boosting step.

[0119] The pressurization steps described above include: a first pressurization step, in which a portion of the processing fluid supplied to the processing container 41 is discharged from the processing container 41 while the pressure inside the processing container 41 is increased; and a second pressurization step, in which, after the first pressurization step, the pressure inside the processing container 41 is increased to a set pressure above the critical pressure while the discharge of processing fluid from the processing container 41 is stopped.

[0120] Specifically, in the first pressurization step, with the on / off valve 52c closed and the on / off valve 52h open, processing fluid is supplied to the interior of the processing container 41 via the supply line L1. This allows processing fluid to be supplied to the interior of the processing container 41 while suppressing the flow rate of the processing fluid.

[0121] In the first pressurization step, the pressure of the processing fluid supplied via the supply line L1 drops significantly as it flows into the relatively large processing container 41, which is under atmospheric pressure. Therefore, the processing fluid enters the interior of the processing container 41 at a high flow rate. Consequently, the processing fluid collides with the liquid film of the IPA, and the liquid in the IPA may overflow from the upper surface of the wafer W. This overflow of the IPA can be suppressed by supplying the processing fluid while simultaneously controlling its flow rate. Furthermore, in the first pressurization step, the pressure of the processing fluid inside the processing container 41 is below a critical pressure (e.g., approximately 8 MPa), therefore, the processing fluid is in a gaseous state.

[0122] In the second pressurization step, with the on / off valves 52c and 52h closed, processing fluid is supplied to the processing container 41 via the supply line L1. That is, processing fluid is supplied to the processing container 41 while the discharge of processing fluid from the processing container 41 is stopped. As a result, the pressure inside the processing container 41 rises to a set pressure above the critical pressure.

[0123] Next, in step S203, the supply line L1 supplies processing fluid to the interior of the processing container 41 via the supply port 45A and the supply head 451A, and the discharge line L2 discharges the fluid from the interior of the processing container 41, allowing the supercritical processing fluid (supercritical fluid) to flow above the wafer W. The IPA dissolved in the supercritical fluid is discharged to the outside of the processing container 41, and the liquid film of IPA on the wafer W is replaced by the supercritical fluid, thereby drying the wafer W. Furthermore, in step S203, the pressure inside the processing container 41 is maintained at the aforementioned set pressure.

[0124] Next, in step S204, the supply line L1 is stopped from supplying processing fluid into the processing container 41, and the discharge line L2 discharges the fluid from inside the processing container 41, thereby reducing the internal pressure of the processing container 41. This reduces the internal pressure of the processing container 41 to approximately atmospheric pressure (0.1 MPa). Afterward, the cover 43 opens the opening 44 of the processing container 41, and the wafer W is removed from the outside of the processing container 41.

[0125] Finally, in step S205, the conveying device 132 receives the wafer W from the holding part 42 and sends the received wafer W to the outside of the drying unit 4.

[0126] Figure 9 This is a schematic diagram illustrating the internal state of the processing container 41 during the boosting step. As described above, during the boosting step, processing fluid is supplied from the bottom of the wafer W to the processing container 41 via the supply port 45B and the supply head 451B. At this time, inside the processing container 41, the processing fluid flows from the lower surface side of the wafer W to the upper surface side.

[0127] Therefore, the shear force generated by the processing fluid will act on the liquid film of IPA formed on the upper surface of wafer W. Figure 9 The surface of the liquid film Q in the wafer. IPA may overflow from the wafer W due to this shear force. In the case of IPA overflow from the wafer W, the amount of IPA on the wafer W will become less than the appropriate amount, thereby the pattern formed on the surface of the wafer W may collapse.

[0128] According to the substrate processing system 1 of the present invention, during the boost step, it is possible to detect abnormalities in the liquid film state, such as IPA overflowing from the wafer W, as will be explained later. Furthermore, according to the substrate processing system 1 of the present invention, when such an abnormality in the liquid film state is detected, the liquid film state can be maintained as normal by performing the adjustment process described later. This suppresses the occurrence of the aforementioned pattern collapse.

[0129] <Functions of the control device>

[0130] Next, the functions of control device 7 will be explained.Figure 10 This is a diagram showing a structural example of the control device 7 in the first embodiment, represented by function blocks. Figure 10 The functional blocks illustrated are conceptual and do not necessarily need to be physically configured as shown. All or part of the functional blocks can be functionally or physically distributed or combined in any unit. All or any part of the processing functions performed by each functional block can be implemented by a program executed by the CPU, or as hardware based on wiring logic.

[0131] The control device 7 has a control unit 71 and a storage unit 72. The control unit 71 includes, for example, a first density calculation unit 73, a second density calculation unit 74, a density difference calculation unit 75, a suitability judgment unit 76, and an adjustment unit 77.

[0132] In the pressure boosting step of the drying process (hereinafter referred to as "pre-processing") performed by the first density calculation unit 73 in a state where no liquid film of IPA has been formed on the wafer W, the pressure is based on the first pressure P detected by the pressure sensor PS2. A and the first temperature T detected by temperature sensor TS4 A This is used to calculate the first density data D1, representing the change in density of the processed fluid over time. Specifically, in the pre-treatment pressurization step, the first pressure P is used. A and the first temperature T A According to the state equation described later, the first density data D1 is calculated every unit time.

[0133] Specifically, the aforementioned pre-processing is performed on the wafer W before the drying process of the product wafer W. Furthermore, the number of wafers W undergoing pre-processing can be multiple; that is, pre-processing can be performed on multiple wafers W individually.

[0134] In this case, the first density calculation unit 73 first uses the detected first pressure P in each preprocessing step. A and the first temperature T A The density of the processing fluid inside the processing container 41 is calculated as a function of time at unit intervals. Then, the first density calculation unit 73 calculates the first density data D1 based on the average value of the density change data as a function of time calculated in each pre-processing step.

[0135] Storage unit 72 stores the first pressure P detected by pressure sensor PS2. A The data on the change over time, the first temperature T detected by temperature sensor TS4 A The data changing over time, and the first density data D1 calculated by the first density calculation unit 73.

[0136] In the pressure boosting step of the drying process (hereinafter referred to as "formal processing") performed by the second density calculation unit 74 in the state where a liquid film of IPA has been formed on the wafer W, the second pressure P is based on the pressure sensor PS2. B and the second temperature T detected by temperature sensor TS4 B The second density data D2, representing the change in density of the processed fluid over time, is calculated by the second density calculation unit 74. Specifically, during the pressurization step of the formal processing, the second density calculation unit 74 uses the second pressure P. B and the second temperature T B According to the state equation described later, the second density data D2 is calculated every unit time.

[0137] Furthermore, the formal processing mentioned here specifically refers to the drying process performed on the product wafer W. This formal processing is carried out after the aforementioned pre-processing.

[0138] The pretreatment and formal treatment are carried out under the same drying conditions. Furthermore, the pretreatment and formal treatment can, for example, be carried out in the same drying unit 4. Additionally, the pretreatment and formal treatment can, for example, be carried out on the same day.

[0139] In the formal processing, the density difference calculation unit 75 calculates the density difference data ΔD, which is the difference between the first density data D1 stored in the storage unit 72 and the second density data D2 calculated by the second density calculation unit 74. Specifically, in the second boost step of the formal processing, the density difference data ΔD is calculated every unit time using the first density data D1 and the second density data D2, by using ΔD = D1 - D2.

[0140] Appropriateness judgment section 76 is based on the second pressure P B Using the density difference data ΔD, determine whether the aforementioned anomaly in the liquid film state occurred during the second pressurization step of the formal processing. Specifically, based on the second pressure P... B The appropriateness of the liquid film state is determined by the rate of change of the density difference data ΔD over time, and an alarm or anomaly assessment is output based on the assessment result. The specific process for determining appropriateness will refer to [reference needed]. Figure 17 and Figure 18 This will be explained later.

[0141] If the suitability determination unit 76 outputs an alarm, the adjustment unit 77 adjusts the parameter value of at least one of a plurality of processing parameters that define the conditions for the drying process during the second pressurization step of the formal processing. These plurality of processing parameters include, for example, the supply flow rate of the processing fluid supplied to the processing container 41, the temperature of the processing fluid supplied to the processing container 41, the volume of the liquid film of the IPA formed on the wafer W, and the temperature of the processing container 41. This adjustment process maintains the liquid film state of the IPA in a normal state. Furthermore, the specific adjustment process performed by the adjustment unit 77 will be described in reference to... Figure 17 and Figure 18 This will be explained later.

[0142] Here, refer to Figures 11-14 The first density data D1, the second density data D2, and the density difference data ΔD are described in detail.

[0143] Figure 11 This is an example graph showing the relationship between density, pressure, and temperature in a supercritical fluid. Figure 11 In this context, T represents the temperature of the supercritical fluid. Temperature T1 is lower than temperature T2, temperature T2 is lower than temperature T3, and temperature T3 is lower than temperature T4. For example... Figure 11 As shown, at a constant pressure, the higher the temperature, the lower the density. Conversely, at a constant temperature, the higher the pressure, the higher the density. The relationship between density, pressure, and temperature of a supercritical fluid is determined beforehand through experiments and stored in the storage unit 72. This relationship can be stored as a formula. Formulas are generally called equations of state.

[0144] Figure 12 This is a graph representing an example of the first density data D1. The first density data D1 uses the first pressure P mentioned above. A and the first temperature T A ,according to Figure 11 The state equations shown are used for calculation. For example... Figure 12 As shown, the value of the first density data D1 changes with the first pressure P. A It increases as it rises. Additionally, in Figure 12 The diagram shows the first pressure P. A Regions below critical pressure and the first pressure P A This refers to the region above the critical pressure. Additionally, in... Figure 12 In this context, region P1 corresponds to the first boost step, and region P2 corresponds to the second boost step.

[0145] Figure 13 This is a graph representing an example of the second density data D2. The second density data D2 uses the second pressure P mentioned above. B and the second temperature T B ,according toFigure 11 The state equations shown are used for calculation. For example... Figure 13 As shown, the value of the second density data D2 changes with the second pressure P. B It increases as it rises. Additionally, in Figure 13 The diagram shows the second pressure P. B Regions below critical pressure and the second pressure P B This refers to the region above the critical pressure. Additionally, in... Figure 13 In this context, region P1 corresponds to the first boost step, and region P2 corresponds to the second boost step.

[0146] During the pressurization step of the formal treatment, a portion of the treatment fluid dissolves in the liquid film of the IPA. Therefore, the second pressure P detected during the formal treatment... B The value is less than the first pressure P detected in the pre-treatment process. A Therefore, the value of the second density data D2 is less than the value of the first density data D1.

[0147] Figure 14 This is a graph representing an example of density difference data. The density difference data ΔD is calculated using the first density data D1 and the second density data D2, as ΔD = D1 - D2. ΔD is a quantity proportional to the amount of process fluid dissolved in the liquid film of IPA during the second pressurization step of the formal treatment. Additionally, as... Figure 14 As shown, the value of ΔD changes with the second pressure P. B The pressure increases as well.

[0148] <Functions of the control device>

[0149] Next, refer to Figure 15 and Figure 16 An outline of the series of anomaly detection processes performed in the control unit 71 of the first embodiment will be described.

[0150] In explaining the process of a series of anomaly detections, we will first explain an example of the data stored in the storage unit 72. Figure 15 This diagram illustrates an example of data stored in the storage unit 72 of the first embodiment. As described above, the first pressure P detected by the pressure sensor PS2... A Data on changes over time ( Figure 15 Data 72a), the first temperature T detected by temperature sensor TS4. A Data on changes over time ( Figure 15 Data 72b), and the first density data D1 calculated by the first density calculation unit 73. Figure 15 The data 72c) is pre-stored in the storage unit 72.

[0151] Next, a summary of the anomaly detection process will be provided. Figure 16 This is a flowchart illustrating a series of anomaly detection processes performed in the control unit 71 of the first embodiment. Furthermore, the following steps are performed at regular intervals during the second boost step of the formal processing.

[0152] First, pressure sensor PS2 detects the second pressure P. B (Step S301A) Temperature sensor TS4 detects the second temperature T B (Step S301B).

[0153] Next, the second density calculation unit 74 uses the second pressure P detected in step S301A. B and the second temperature T detected in step S301B B ,according to Figure 11 The state equation shown is used to calculate the second density data D2 (step S302).

[0154] Next, the density difference calculation unit 75 uses the first density data D1 pre-stored in the storage unit 72 and the second density data D2 calculated in step S302 to calculate the density difference data ΔD according to the state equation (step S303).

[0155] Next, the appropriateness judgment unit 76 determines the appropriateness based on the second pressure P detected in step S301A. B The time change rate of the density difference data ΔD calculated in step S303 is used to determine whether the state of the IPA liquid film is appropriate, and an alarm or anomaly judgment is output (step S304). The specific procedure for determining appropriateness will refer to... Figure 17 and Figure 18 This will be explained later.

[0156] Next, when the appropriateness determination unit 76 outputs an alarm in step S304, the adjustment unit 77 adjusts the supply flow rate of the processing fluid supplied to the processing container 41 (step S305). As a result, the liquid film state of the IPA of the wafer W can be maintained at a normal level.

[0157] In step S305, the adjustment unit 77 can adjust at least one of the aforementioned processing parameters that define the drying conditions. The following explanation will take the case of adjusting the supply flow rate of the processing fluid as an example. Furthermore, the specific process for adjusting the supply flow rate will be described in [reference needed]. Figure 17 and Figure 18 This will be explained later.

[0158] Next, refer to Figure 17 and Figure 18The details of the suitability determination performed in the suitability determination unit 76 of the first embodiment will be explained. Figure 17 This is a graph representing an example of density difference data ΔD that includes anomalies from the drying process. Figure 17 In the middle, ΔD α This is an example of how the density difference data ΔD changes over time in the pressurization step of the formal treatment, assuming no anomalies in the liquid film state. β This is an example illustrating the time-varying density difference data ΔD under conditions where anomalies in the liquid film state occur during the pressurization step of the formal processing. Below, we present the density difference data ΔD... β Taking this as an example, we will explain the details of judging whether something is appropriate or not.

[0159] First, for the density difference data ΔD β The characteristics will be explained. As mentioned above, the density difference data ΔD is proportional to the amount of processing fluid in the liquid film dissolved in the IPA during the second pressurization step of the formal processing. For example, if the liquid IPA overflows from the upper surface of the wafer W, the overflowing IPA will vaporize inside the processing container 41. As a result, the amount of liquid IPA in the liquid film state decreases, and therefore, the amount of processing fluid that can dissolve in the liquid film of IPA also decreases. Therefore, as Figure 17 As shown, when IPA begins to overflow from wafer W, the density difference data ΔD β The rate of change over time, i.e. Figure 17 ΔD in β The slope begins to decrease. Furthermore, when all IPA overflows from wafer W, the density difference data ΔD... β The value becomes 0.

[0160] Appropriateness judgment section 76, for example, in density difference data ΔD β An alarm is output if the rate of change over time is below a first threshold and above a second threshold that is smaller than the first threshold. Specifically, for example, the first threshold could be 0.1. Alternatively, for example, the second threshold could be -0.1. That is, the appropriateness determination unit 76 determines the appropriateness of the density difference data ΔD. β An alarm is output when the rate of change over time becomes close to 0. In this way, the appropriateness determination unit 76 can detect the occurrence of IPA overflow from the chip W.

[0161] In addition, Figure 17 In the diagram, time 'a' represents the density difference data ΔD. β The rate of change over time becomes the elapsed time from the start of formal processing for the first threshold. Additionally, time b represents the density difference data ΔD. β The rate of change over time becomes the second threshold, which is the elapsed time from the start of formal processing.

[0162] Additionally, the appropriateness judgment unit 76, for example, in the density difference data ΔD β If the rate of change over time is below the second threshold, an anomaly judgment is output. In this way, the suitability judgment unit 76 can detect an anomaly in the liquid film state when excessive overflow of IPA from the wafer W occurs.

[0163] Furthermore, the appropriateness determination unit 76 can output information indicating that an alarm or abnormality determination has been issued, for example, to an external device. This allows the operator to be notified of the occurrence of an alarm or abnormality determination.

[0164] Next, the process of determining appropriateness in the appropriateness determination unit 76 will be explained. Figure 18 This is a flowchart illustrating the process of determining suitability in the suitability determination unit 76 of the first embodiment.

[0165] First, control unit 71 determines the second pressure P. B Is it above the critical pressure (step S401)? At the second pressure P... B If the pressure is not above the critical pressure (step S401, no), the control unit 71 repeatedly executes step S401.

[0166] Next, at the second pressure P B If the critical pressure is above (step S401, yes), the appropriateness determination unit 76 determines whether the time change rate of the density difference data ΔD is below the first threshold and above the second threshold (step S402).

[0167] In step S402, if the rate of change of the density difference data ΔD over time is within the aforementioned threshold range (step S402, Yes), the appropriateness determination unit 76 outputs an alarm. If an alarm is output, the adjustment unit 77, for example, suppresses the supply flow rate of the processing fluid supplied to the processing container 41 (step S403).

[0168] Specifically, the regulating unit 77 can, for example, temporarily stop the supply of processing fluid from the supply line L1, and then restart the supply of processing fluid after adjusting the parameter value of the supply flow rate. Furthermore, if an alarm is issued again after adjusting the parameter value, the regulating unit 77 can, for example, control the opening degree of the pressure reducing valve 53 while the on / off valve 52c of the on / off line L2a is open, to suppress the supply flow rate of processing fluid to the processing container 41.

[0169] According to this structure, the shear force generated by the processing fluid acting on the surface of the liquid film of IPA can be reduced. This reduces the occurrence of IPA overflow from the wafer W.

[0170] The shear force generated by the processing fluid is proportional to the diffusion rate N, which represents the rate at which the liquid IPA inside the processing container 41 diffuses into the gaseous processing fluid. This diffusion rate N can be calculated using the temperature T, density ρ, and viscosity μ of the diffused IPA and gaseous processing fluid mixture, the supply flow rate u of the processing fluid to the processing container 41, and the distance L between the upper surface of the processing container 41 and the upper surface of the liquid film of the IPA, with N = T. (2 / 3) ρ (1 / 6) μ (-5 / 6) u (1 / 2) L (-1 / 2) To calculate.

[0171] Furthermore, the regulating unit 77 can also suppress the temperature of the processing fluid supplied to the processing container 41 by adjusting the heating temperature of the heater provided in the supply line L1. Alternatively, the processing container 41 can be connected to a heating mechanism (not shown), and the regulating unit 77 can also suppress the temperature of the processing container 41 by adjusting the heating temperature of this heating mechanism. With this structure, the shear force generated by the processing fluid can also be reduced.

[0172] Furthermore, the adjustment unit 77 can also suppress the supply flow rate of IPA supplied to the upper surface of the wafer W during the liquid film formation process performed by the liquid processing unit 2. Specifically, the adjustment unit 77 can also adjust the value of a parameter specifying the supply flow rate of IPA supplied by the liquid processing unit 2. According to this structure, the supply flow rate of IPA supplied by the liquid processing unit 2 can be suppressed during substrate processing performed after the formal processing that has output an alarm. As described above, by suppressing the amount of liquid in the IPA liquid film, the occurrence of IPA overflow can also be reduced.

[0173] Furthermore, the storage unit 72 may also store identification information of the wafer W that has been adjusted by the adjustment unit 77 during formal processing. Specifically, this identification information may be, for example, an identification number associated with each wafer W.

[0174] Next, in step S402, if the time change rate of the density difference data ΔD is outside the range of the above threshold (step S402, no), or after the processing in step S403 is completed, the appropriateness determination unit 76 determines whether the time change rate of the density difference data ΔD is below the second threshold (step S404).

[0175] In step S404, if the time change rate of the density difference data ΔD is below the second threshold (step S404, Yes), the suitability determination unit 76 outputs an anomaly determination. If an anomaly determination is output, an anomaly response process is implemented (step S405). Specifically, for example, an anomaly response process such as discarding the wafer W determined to be abnormal as a defective product can be implemented. Alternatively, as an anomaly response process, for example, the liquid processing unit 2 that performs liquid film formation processing on the wafer W for which an anomaly determination has been output can be stopped.

[0176] In step S404, if the time change rate of the density difference data ΔD is not below the second threshold (step S404, no), or after the processing in step S405 is completed, the appropriateness determination unit 76 ends a series of appropriateness determinations.

[0177] <Second Implementation>

[0178] Next, refer to Figures 19-21 The control unit 71 of the second embodiment will be described. Figure 19 This is a diagram illustrating a structural example of the control device 7 in the second embodiment, represented using function blocks. (See diagram for example.) Figure 19 As shown, the control unit 71 in the second embodiment also includes a prediction and judgment unit 78, which is used to predict the alarm output of the appropriateness judgment unit 76.

[0179] The prediction and judgment unit 78 can predict the alarm output of the appropriateness judgment unit 76 and output an attention report based on the shear force generated by the processing fluid calculated according to the supply flow rate of the processing fluid supplied to the processing container 41 and the surface tension of the liquid film of IPA calculated according to the second density data D2.

[0180] The storage unit 72 in the second embodiment can pre-store information about the relationship between the supply flow rate of the processing fluid and the shear force generated by the processing fluid acting on the liquid film surface of the IPA. This relationship information may be, for example, information about the distribution of the shear force generated, calculated through simulation under different supply flow rates of the processing fluid.

[0181] The prediction and judgment unit 78 can use the information about the generation and distribution of the shear force stored in the storage unit 72 to calculate the maximum value of the shear force acting on the surface of the liquid film of the IPA based on the supply flow rate of the processing fluid.

[0182] Furthermore, the prediction and judgment unit 78 can use the second density data D2 and, for example, a known formula for calculating the surface tension of ethanol present in a CO2 atmosphere to calculate the surface tension σ of the liquid film of IPA. Specifically, the prediction and judgment unit 78 can, for example, calculate the surface tension σ of the liquid film of IPA using the formula: σ = c + (dc) / (1 + exp(-a(D2-b))) f To calculate the surface tension σ. Furthermore, a, b, c, d, and f mentioned above are constants stated in well-known formulas.

[0183] Figure 20 This is a flowchart illustrating a series of anomaly detection processes performed in the control unit 71 of the second embodiment. Figure 20 In the process, all processes other than step S504 are related to... Figure 16 The processes in steps S301A to S306 are the same, so the explanation here is omitted.

[0184] The prediction and judgment unit 78 can predict the alarm output of the suitability judgment unit 76 after the density difference data ΔD is calculated and processed in step S503 and before the suitability judgment process of the liquid film state in step S505, and output an attention report (step S504).

[0185] Figure 21 This is a flowchart illustrating the prediction and determination process performed in the prediction and determination unit 78 of the second embodiment. Furthermore, Figure 21 The processing of step S602 in the process and Figure 18 The process in step S403 is the same.

[0186] First, the prediction and judgment unit 78 determines whether the calculated maximum value of the above-mentioned shear force is above or above a preset third threshold and whether the calculated surface tension σ of the liquid film of the above-mentioned IPA is below or below a preset fourth threshold (step S601).

[0187] In step S601, if the maximum value of the shear force is less than the third threshold or the surface tension σ of the liquid film of the IPA is greater than the fourth threshold (step S601, no), the prediction and judgment unit 78 ends the judgment process.

[0188] In step S601, if the maximum value of the shear force is above the third threshold and the calculated surface tension σ of the liquid film of the IPA is below the fourth threshold (step S601, Yes), the prediction and judgment unit 78 determines that the IPA may overflow from the wafer W, and the appropriateness judgment unit 76 outputs an alarm and a warning report. If a warning report is output, the adjustment unit 77, for example, suppresses the supply flow rate of the processing fluid supplied to the processing container 41 (step S602).

[0189] Furthermore, the third and fourth thresholds can be the same value. That is, in this case, the prediction and judgment unit 78 outputs a warning report when the maximum value of the shear force is greater than the surface tension σ.

[0190] Based on this structure, the occurrence of IPA overflow from the wafer W can be predicted before an alarm is output by the appropriateness judgment unit 76. Therefore, the generation of abnormalities in the liquid film state can be more appropriately suppressed.

[0191] (Other variations)

[0192] Up to this point, an example has been described where the regulating unit 77 uses information about the relationship between the supply flow rate of the processing fluid and the shear force generated by the processing fluid to predict the occurrence of an alarm in the appropriateness judgment unit 76. However, the regulating unit 77 may also adjust the parameter value based on information about the relationship between the liquid film state of the IPA pre-stored in the storage unit 72 and the parameter value of the processing parameter, thereby maintaining the liquid film state of the IPA at a normal level.

[0193] Specifically, the information regarding this correlation could be, for example, the parameter values ​​of the processing parameters and the generation distribution of shear forces generated by the processing fluid acting on the liquid film surface of the IPA. Alternatively, it could be information indicating the correlation between the parameter values ​​of the processing parameters in the formal processing and the generation distribution of pattern collapse actually produced in that formal processing.

[0194] In addition, the storage unit 72 can also store information such as the generation distribution of the shear force and the generation distribution of the pattern collapse in the multiple formal processes, as well as the parameter values ​​of the multiple processing parameters in the multiple formal processes, as big data.

[0195] The adjustment unit 77 can also control the output of the attention report of the prediction and judgment unit 78 by performing AI analysis on the big data. That is, the adjustment unit 77 can, for example, calculate the output conditions of the attention report by comprehensively analyzing the information contained in the big data and performing machine learning.

[0196] The present invention has been described in detail above, but the present invention is not limited to the above-described embodiments. Various changes and improvements can be made without departing from the spirit of the present invention.

[0197] The embodiments disclosed herein should be considered illustrative rather than limiting in all respects. In fact, the above embodiments can be implemented in various ways. Furthermore, the above embodiments can be omitted, substituted, or modified in various ways without departing from the appended claims and their spirit.

[0198] In addition, the present invention can also adopt the following technical solutions. (1)

[0200] A substrate processing apparatus, characterized in that it comprises:

[0201] The processing container is capable of drying the substrate by supplying a processing fluid into the interior of the processing container, thereby replacing the liquid film of the drying liquid formed on the substrate with the processing fluid in a supercritical state.

[0202] A pressure detection unit capable of detecting the pressure of the processing fluid inside the processing container;

[0203] A temperature detection unit is capable of detecting the temperature of the processing fluid inside the processing container; and

[0204] Control Department

[0205] The drying process includes a pressurization step of increasing the pressure inside the processing container to a set pressure above a critical pressure by supplying the processing fluid into the processing container.

[0206] The control unit includes:

[0207] The first density calculation unit calculates, in the pressurization step of the pre-processing, first density data representing the change of density of the processing fluid over time based on the first pressure detected by the pressure detection unit and the first temperature detected by the temperature detection unit, wherein the pre-processing is the drying process performed in a state where no liquid film of the drying liquid has been formed on the substrate.

[0208] The second density calculation unit calculates, in the pressurization step of the formal processing, a second density data representing the change of the density of the processing fluid over time based on the second pressure detected by the pressure detection unit and the second temperature detected by the temperature detection unit, wherein the formal processing is the drying process performed in the state where a liquid film of the drying liquid is formed on the substrate.

[0209] The density difference calculation unit calculates the density difference data as the difference between the first density data and the second density data; and

[0210] The suitability determination unit, based on the density difference data, determines whether the state of the liquid film of the drying liquid formed on the substrate is appropriate during the formal processing. (2)

[0212] According to the substrate processing apparatus described in (1) above, the feature is that:

[0213] The pressurization step includes: a first pressurization step, in which a portion of the processing fluid supplied to the processing container is discharged from the processing container while the pressure inside the processing container is increased; and a second pressurization step, in which, after the first pressurization step, the pressure inside the processing container is increased to a set pressure above a critical pressure while the discharge of the processing fluid from the processing container is stopped.

[0214] The density difference calculation unit calculates the density difference data in the second pressurization step. (3)

[0216] According to the substrate processing apparatus described in (2) above, the feature is:

[0217] During each elapsed time period starting from the start of the second pressurization step, the value of the first density data is greater than the value of the second density data. (4)

[0219] According to the substrate processing apparatus described in (3) above, the feature is:

[0220] Including the storage section,

[0221] The density difference calculation unit uses the first density data pre-stored in the storage unit and the second density data calculated by the second density calculation unit to calculate the density difference data. (5)

[0223] The substrate processing apparatus according to (3) or (4) above is characterized in that:

[0224] The suitability determination unit determines whether the state of the liquid film of the drying liquid is appropriate based on the time change rate of the second pressure and the density difference data. (6)

[0226] According to the substrate processing apparatus described in (5) above, the feature is that:

[0227] When the second pressure is above the critical pressure, the appropriateness judgment unit outputs an alarm when the time change rate of the density difference data is below the first threshold and above the second threshold which is smaller than the first threshold, and judges the drying process as abnormal when the time change rate of the density difference data is less than the second threshold. (7)

[0229] According to the substrate processing apparatus described in (6) above, the feature is that:

[0230] The control unit includes a prediction and judgment unit that can predict the generation of the alarm and output an attention report based on the shear force generated by the processing fluid at the liquid film interface of the drying liquid calculated according to the supply flow rate of the processing fluid and the surface tension of the liquid film of the drying liquid calculated according to the second density data. (8)

[0232] According to the substrate processing apparatus described in (7) above, the feature is:

[0233] The control unit includes an adjustment unit that, during the formal processing, can adjust at least one of the following parameters among a plurality of processing parameters in the drying process: the supply flow rate of the processing fluid supplied to the processing container, the temperature of the processing fluid supplied to the processing container, the volume of the liquid film of the drying liquid formed on the substrate, and the temperature of the processing container, based on the alarm or the attention report. (9)

[0235] According to the substrate processing apparatus described in (8) above, the feature is:

[0236] When the appropriateness determination unit outputs the alarm, the adjustment unit adjusts the supply flow rate of the processing fluid supplied to the processing container. (10)

[0238] The substrate processing apparatus according to (8) or (9) above is characterized in that:

[0239] When the prediction and judgment unit outputs the attention report, the adjustment unit adjusts the supply flow rate of the processing fluid. (11)

[0241] According to the substrate processing apparatus described in (8) above, the feature is:

[0242] Including the storage section,

[0243] The adjustment unit adjusts the parameter value based on the correlation between the state of the liquid film of the drying liquid pre-stored in the storage unit and the parameter value of the processing parameter. (12)

[0245] The substrate processing apparatus according to any one of (1) to (11) above is characterized in that: the processing fluid is CO2. (13)

[0247] A substrate processing method, which is a substrate processing method in a substrate processing apparatus.

[0248] The substrate processing apparatus includes:

[0249] The processing container is capable of drying the substrate by supplying a processing fluid into the interior of the processing container, thereby replacing the liquid film of the drying liquid formed on the substrate with the processing fluid in a supercritical state.

[0250] A pressure detection unit capable of detecting the pressure of the processing fluid inside the processing container;

[0251] A temperature detection unit is capable of detecting the temperature of the processing fluid inside the processing container; and

[0252] Control Department

[0253] The substrate processing method is characterized by:

[0254] The drying process includes a pressurization step of increasing the pressure inside the processing container to a predetermined critical pressure by supplying the processing fluid into the interior of the processing container.

[0255] The control unit is capable of controlling the substrate processing device to perform the following:

[0256] In the pressurization step of the pre-processing, a step of calculating a first density data representing the change of the density of the processing fluid over time is performed based on a first pressure detected by the pressure detection unit and a first temperature detected by the temperature detection unit, wherein the pre-processing is the drying process performed in a state where no liquid film of the drying liquid has been formed on the substrate.

[0257] In the pressurization step of the formal processing, a step of calculating a second density data representing the change of the density of the processing fluid over time is performed based on a second pressure detected by the pressure detection unit and a second temperature detected by the temperature detection unit, wherein the formal processing is the drying process performed in the state where a liquid film of the drying liquid is formed on the substrate.

[0258] The step of calculating the density difference data, which is the difference between the first density data and the second density data; and

[0259] Based on the density difference data, the formal processing step involves determining whether the state of the liquid film of the drying liquid formed on the substrate is appropriate.

Claims

1. A substrate processing apparatus, characterized in that, include: The processing container is capable of drying the substrate by supplying a processing fluid into the interior of the processing container, thereby replacing the liquid film of the drying liquid formed on the substrate with the processing fluid in a supercritical state. A pressure detection unit capable of detecting the pressure of the processing fluid inside the processing container; A temperature detection unit is capable of detecting the temperature of the processing fluid inside the processing container; and Control Department The drying process includes a pressurization step of increasing the pressure inside the processing container to a set pressure above a critical pressure by supplying the processing fluid into the processing container. The control unit includes: The first density calculation unit calculates, in the pressurization step of the pre-processing, first density data representing the change of density of the processing fluid over time based on the first pressure detected by the pressure detection unit and the first temperature detected by the temperature detection unit, wherein the pre-processing is the drying process performed in a state where no liquid film of the drying liquid has been formed on the substrate. The second density calculation unit calculates, in the pressurization step of the formal processing, a second density data representing the change of the density of the processing fluid over time based on the second pressure detected by the pressure detection unit and the second temperature detected by the temperature detection unit, wherein the formal processing is the drying process performed in the state where a liquid film of the drying liquid is formed on the substrate. The density difference calculation unit calculates the density difference data as the difference between the first density data and the second density data; and The suitability determination unit, based on the density difference data, determines whether the state of the liquid film of the drying liquid formed on the substrate is appropriate during the formal processing.

2. The substrate processing apparatus according to claim 1, characterized in that: The pressurization step includes: a first pressurization step, in which a portion of the processing fluid supplied to the processing container is discharged from the processing container while the pressure inside the processing container is increased; and a second pressurization step, in which, after the first pressurization step, the pressure inside the processing container is increased to a set pressure above a critical pressure while the discharge of the processing fluid from the processing container is stopped. The density difference calculation unit calculates the density difference data in the second pressurization step.

3. The substrate processing apparatus according to claim 2, characterized in that: During each elapsed time period starting from the start of the second pressurization step, the value of the first density data is greater than the value of the second density data.

4. The substrate processing apparatus according to claim 3, characterized in that: Including the storage section, The density difference calculation unit uses the first density data pre-stored in the storage unit and the second density data calculated by the second density calculation unit to calculate the density difference data.

5. The substrate processing apparatus according to claim 3, characterized in that: The suitability determination unit determines whether the state of the liquid film of the drying liquid is appropriate based on the time change rate of the second pressure and the density difference data.

6. The substrate processing apparatus according to claim 5, characterized in that: When the second pressure is above the critical pressure, the appropriateness judgment unit outputs an alarm when the time change rate of the density difference data is below the first threshold and above the second threshold which is smaller than the first threshold, and judges the drying process as abnormal when the time change rate of the density difference data is less than the second threshold.

7. The substrate processing apparatus according to claim 6, characterized in that: The control unit includes a prediction and judgment unit that can predict the generation of the alarm and output an attention report based on the shear force generated by the processing fluid at the liquid film interface of the drying liquid calculated according to the supply flow rate of the processing fluid and the surface tension of the liquid film of the drying liquid calculated according to the second density data.

8. The substrate processing apparatus according to claim 7, characterized in that: The control unit includes an adjustment unit that, during the formal processing, can adjust at least one of the following parameters among a plurality of processing parameters in the drying process: the supply flow rate of the processing fluid supplied to the processing container, the temperature of the processing fluid supplied to the processing container, the volume of the liquid film of the drying liquid formed on the substrate, and the temperature of the processing container, based on the alarm or the attention report.

9. The substrate processing apparatus according to claim 8, characterized in that: When the appropriateness determination unit outputs the alarm, the adjustment unit adjusts the supply flow rate of the processing fluid supplied to the processing container.

10. The substrate processing apparatus according to claim 8, characterized in that: When the prediction and judgment unit outputs the attention report, the adjustment unit adjusts the supply flow rate of the processing fluid.

11. The substrate processing apparatus according to claim 8, characterized in that: Including the storage section, The adjustment unit adjusts the parameter value based on the correlation between the state of the liquid film of the drying liquid pre-stored in the storage unit and the parameter value of the processing parameter.

12. The substrate processing apparatus according to any one of claims 1 to 11, characterized in that: The processing fluid is CO2.

13. A substrate processing method, which is a substrate processing method in a substrate processing apparatus. The substrate processing apparatus includes: The processing container is capable of drying the substrate by supplying a processing fluid into the interior of the processing container, thereby replacing the liquid film of the drying liquid formed on the substrate with the processing fluid in a supercritical state. A pressure detection unit capable of detecting the pressure of the processing fluid inside the processing container; A temperature detection unit is capable of detecting the temperature of the processing fluid inside the processing container; and Control Department The substrate processing method is characterized by: The drying process includes a pressurization step of increasing the pressure inside the processing container to a predetermined critical pressure by supplying the processing fluid into the interior of the processing container. The control unit is capable of controlling the substrate processing device to perform the following: In the pressurization step of the pre-processing, a step of calculating a first density data representing the change of the density of the processing fluid over time is performed based on a first pressure detected by the pressure detection unit and a first temperature detected by the temperature detection unit, wherein the pre-processing is the drying process performed in a state where no liquid film of the drying liquid has been formed on the substrate. In the pressurization step of the formal processing, a step of calculating a second density data representing the change of the density of the processing fluid over time is performed based on a second pressure detected by the pressure detection unit and a second temperature detected by the temperature detection unit, wherein the formal processing is the drying process performed in the state where a liquid film of the drying liquid is formed on the substrate. The step of calculating the density difference data, which is the difference between the first density data and the second density data; and Based on the density difference data, the formal processing step involves determining whether the state of the liquid film of the drying liquid formed on the substrate is appropriate.

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