Substrate processing apparatus and substrate processing method

Abstract

A substrate processing apparatus includes: a batch processing unit having multiple batch processing units that perform liquid processing on multiple substrates simultaneously in a processing liquid stored in a processing tank; a single-substrate processing unit that processes substrates processed by the batch processing unit one by one; a standby unit that keeps substrates processed by the batch processing unit in standby in an impregnation liquid in an impregnation tank; and a transport system including a first substrate transport unit that removes substrates one by one from the aforementioned impregnation liquid for transporting substrates from the standby unit to the single-substrate processing unit; the standby unit performs at least one of a first liquid treatment on the substrates to make the substrate surface hydrophilic or to increase or maintain the hydrophilicity of the substrate surface, and a second liquid treatment to make the zeta potential of the substrate surface negative.

Description

Technical Field

[0001] This disclosure relates to a substrate processing apparatus and a substrate processing method. Prior Technology

[0002] In the manufacture of semiconductor devices, liquid processing, such as wet etching or cleaning, is performed on substrates like semiconductor wafers by supplying a chemical solution to the substrate. Patent Document 1 describes a substrate processing system for performing such liquid processing on substrates. The substrate processing system includes a chemical solution tank, a washing tank, a washing buffer tank, a transfer unit, and a rotary drying unit. In the chemical solution tank, multiple substrates undergo batch chemical solution processing; in the washing tank, the chemically treated substrates undergo batch washing; and in the rotary drying unit, each of the washed substrates undergoes individual shaking and drying. The washing buffer tank temporarily holds the washed substrates in water. The transfer unit transfers the substrates held in the washing buffer tank one by one to the rotary drying unit. [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent No. 3192951 Summary of the Invention

[0004] This disclosure provides a technique for preventing the surface condition of a substrate from deteriorating when transferring the substrate from a batch processing unit to a single-wafer processing unit.

[0005] One embodiment of the substrate processing apparatus disclosed herein includes: a batch processing unit having multiple batch processing units, each of which has a processing tank for storing processing liquid and is configured to immerse multiple substrates in the processing liquid stored in the processing tank for liquid processing of the multiple substrates simultaneously; a single-piece processing unit having single-piece processing units that process the multiple substrates processed by the batch processing unit one by one; and a standby unit having an immersion tank for storing immersion liquid and immersing the multiple substrates processed by the batch processing unit in the immersion liquid. The system is in a standby state; and a conveying system for conveying the aforementioned multiple substrates from the aforementioned standby unit to the aforementioned single-substrate processing unit, and includes a first substrate conveying unit for taking out the aforementioned multiple substrates immersed in the aforementioned impregnation liquid in the aforementioned impregnation tank one by one from the aforementioned impregnation liquid; the aforementioned standby unit is configured to perform at least one of a first liquid treatment and a second liquid treatment on the aforementioned substrate, the aforementioned first liquid treatment being a liquid treatment that makes the surface of the aforementioned substrate hydrophilic, or a liquid treatment that increases or maintains the hydrophilicity of the surface of the aforementioned substrate, and the aforementioned second liquid treatment being a liquid treatment that makes the zeta potential of the surface of the aforementioned substrate negative.

[0006] According to one embodiment of the present disclosure, when the substrate is transferred from the batch processing unit to the single-wafer processing unit, the deterioration of the substrate surface condition can be prevented. Simple Explanation of the Diagram

[0007] [Figure 1] is a schematic cross-sectional view of a substrate processing system according to one embodiment of the substrate processing apparatus. [Figure 2] is a schematic side view showing an example configuration of the standby unit and its associated devices. [Figure 3] is a schematic top view showing an example configuration of the standby unit and its associated devices. [Figure 4] is a schematic front view illustrating the function of the third substrate transport robot in removing the substrate from the substrate holding part of the standby unit. [Figure 5] is a schematic front view illustrating the function of the standby unit's substrate holder when the robot receives the substrate from the second substrate. [Figure 6] is a schematic longitudinal sectional view showing one configuration example of a monolithic liquid processing unit. [Figure 7] is a schematic longitudinal sectional view showing one configuration example of a supercritical drying unit. [Figure 8] is a schematic longitudinal sectional view showing one configuration example of the substrate junction unit. [Figure 9] is a schematic cross-sectional view showing the structure of the etched object in a specific example 1 of the substrate processing method. [Figure 10] is a schematic cross-sectional view showing the structure of the etched object in specific examples 2 and 3 of the substrate processing method. [Fig. 11] is a schematic longitudinal sectional view of the immersion tank in a first configuration example of the standby unit as another embodiment of the substrate processing apparatus. [Fig. 12] is a schematic longitudinal sectional view of the immersion tank in a second configuration example of the standby unit as another embodiment of the substrate processing apparatus. [Fig. 13] is a schematic longitudinal sectional view of the immersion tank in a third configuration example of the standby unit as another embodiment of the substrate processing apparatus. [Fig. 14] is a schematic longitudinal sectional view of the immersion tank in the fourth configuration example of the standby unit, which is another embodiment of the substrate processing apparatus. [Figure 15] is a Pourbaix diagram illustrating the metal loss of tungsten. Implementation

[0008] The following description, with reference to the accompanying drawings, describes an embodiment of the substrate processing apparatus of this disclosure, specifically a substrate processing system 1. To simplify the explanation of orientation, an XYZ orthogonal coordinate system is set and displayed in the lower left of FIG1. ​​The Z-direction is the vertical direction, and the positive Z-direction is the upward direction.

[0009] As shown in Figure 1, one embodiment of the substrate processing apparatus of this disclosure includes a substrate processing system 1, comprising a container loading / unloading section 2, a first interface section 3, a batch processing section 4, a second interface section 5, and a single-wafer processing section 6.

[0010] The substrate processing system 1 includes a control device 100. The control device 100 is configured as a computer and includes an arithmetic processing unit 101 and a memory unit 102. The memory unit 102 stores programs (including processing recipes) for controlling various processes executed in the substrate processing system 1. The arithmetic processing unit 101 reads and executes the programs stored in the memory unit 102, controls the operation of each component of the substrate processing system 1 (described later), and executes a series of processes (described later). The control device 100 may include a user interface such as a keyboard, a touch panel, and a display. The programs may be recorded in a computer-readable memory medium or installed from that memory medium into the memory unit 102 of the control device 100. Examples of computer-readable memory media include hard disks (HD), floppy disks (FD), optical discs (CD), magneto-optical discs (MO), and memory cards.

[0011] The container loading / unloading section 2 has a platform section 21 for placing a substrate transport container F (hereinafter referred to as "container F") such as a FOUP and a container storage section 22 for storing the container F. Multiple movable stages 211 (four in the example) are arranged side-by-side along the Y direction on the platform section 21. A partition wall 212 is provided between the platform section 21 and the container storage section 22. Openings with gates (not shown) are provided in the partition wall 212 at positions corresponding to each movable stage 211. Containers F placed on the movable stages 211 can move into the container storage section 22 through the openings opened by the gates.

[0012] The container storage section 22 is equipped with multiple container holding platforms 221 and a container transport robot (container transport mechanism) 222. The container transport robot 222 is capable of transporting containers F between a movable stage 211 located within the container storage section 22 and any of the container holding platforms 221. One (or two) of the multiple container holding platforms 221 on the first interface side 3 is a substrate removal platform 221A, and the other is a substrate storage platform 221B.

[0013] A partition wall 223 is provided between the container storage section 22 and the first interface section 3. At the position of the partition wall 223 corresponding to the substrate removal platform 221A, there is an opening with a gate (not shown) and an opening and closing mechanism (not shown) for the lid of the container F.

[0014] A first substrate transfer robot (first transfer mechanism) 31 is provided in the first interface 3. The first substrate transfer robot 31 has multiple (e.g., 5 to 25) substrate holders 32 as end effectors. The first substrate transfer robot 31 removes multiple (e.g., 5 to 25) substrates W from the container F placed on the substrate removal platform 221A and transfers them to the second substrate transfer robot (second transfer mechanism) 41 (shown as dashed lines) waiting in the transfer area 33. At this time, the first substrate transfer robot 31 removes the substrates W that are stored in the container F in a horizontal position from the container F and changes them to a vertical position before transferring them to the second substrate transfer robot 41.

[0015] The batch processing unit 4 can process 50 substrates at a time (the quantity of two containers). In this case, a spacing adjustment mechanism for changing the spacing between the substrate holders 32 can be provided on the end effector of the first substrate transport robot 31, or a spacing adjustment mechanism can be provided on the transfer area 33. The spacing adjustment mechanism is, for example, a mechanism that sets the arrangement spacing (pitch) of the substrates W to 1 / 2 of the arrangement spacing when the substrates W are housed in the container F, which is a well-known technology in this field.

[0016] In the following description, it is assumed that 25 substrates W constitute one batch (in the batch processing unit 4, 25 substrates are processed at the same time each time).

[0017] Multiple batch processing units 42 are provided in the batch processing unit 4. Although four batch processing units 42 are depicted in FIG1, the number of batch processing units 42 is not limited to this, and a number of batch processing units 42 corresponding to the number of substrates W to be processed can be provided. The basic configuration of the multiple batch processing units 42 is generally the same, including a processing tank for storing processing liquid, a substrate holder (called a crystal boat, etc.) for holding the substrates in the processing tank, and a lifting mechanism for lifting the substrate holder. The substrate holder can, for example, hold 25 substrates W in a vertical position at equal intervals in the horizontal direction. The multiple batch processing units 42 are arranged in the X direction.

[0018] Multiple batch processing units 42 may include general-purpose batch processing units capable of handling a wide variety of processes, and batch processing units specifically designed for particular processes. The latter is exemplified by a batch processing unit for phosphoric acid (H₃PO₄) processing. In phosphoric acid processing, the processing solution in the processing tank is typically at a high temperature and boiling, and bubbles may also be generated. To address this, the batch processing unit for phosphoric acid processing may include, for example, a cover for closing the upper opening of the processing tank, a mechanism for monitoring and maintaining the boiling state of the processing solution, a bubbling nozzle, and a mechanism for pressing the substrate against a substrate holder.

[0019] Multiple batch processing units 42 include, for example, a first chemical solution processing unit, a first rinsing processing unit, a second chemical solution processing unit, and a second rinsing processing unit. The substrate W is sequentially immersed in the first chemical solution processing unit, the first rinsing processing unit, the second chemical solution processing unit, and the second rinsing processing unit. In each batch processing unit 42, processing (chemical solution processing or DIW rinsing processing) is performed according to the liquid stored in the processing tank. Specific examples of the processing performed in the batch processing unit 42 will be described later.

[0020] At the position closest to the first interface 3 of the batch processing unit 4, there is a substrate holding part 413 for the second substrate conveying robot 41 and a cleaning unit 43 for drying when necessary.

[0021] The standby unit (standby section) 44 is located at the position furthest from the first interface 3 of the batch processing section 4. The standby unit 44 includes an impregnation tank 441 for storing impregnation liquid for impregnating the substrates W, a substrate holder 442 (also called a crystal boat) for holding the substrates within the impregnation tank 441, and a moving mechanism 443 capable of raising and lowering the substrate holder 442 and moving it horizontally (see Figures 2 and 3). The substrate holder 442, for example, can hold 25 substrates W at equal intervals in a vertical position in the horizontal direction. In the standby unit 44, a process is performed to change the surface state of the substrates W in preparation for subsequent single-piece transport. Specifically, this process may be, for example, a hydrophilic treatment to prevent out-of-liquidity of the substrate W surface, or a process to set the zeta potential of the substrate W surface to a negative potential to prevent particles from adhering to the substrate W surface. The detailed configuration of the standby unit 44 will be described later.

[0022] The processing liquid stored in the batch processing unit 42, which is used to process the substrate W before it is put into the standby unit 44, should not be a processing liquid that hinders the processing performed in the standby unit 44. It is usually a rinsing liquid, specifically, for example, DIW.

[0023] The aforementioned second substrate transport robot 41 is provided in the batch processing unit 4. The second substrate transport robot 41 includes a guide rail 411 extending along the arrangement direction (X direction) of the plurality of batch processing units 42, a walking body 412 capable of walking along the guide rail 411, and a substrate holding part 413 mounted on the walking body 412.

[0024] The substrate holding portion 413 has, for example, three substrate holding rods 414 extending along the Y direction. Each substrate holding rod 414 has substrate holding grooves (not shown) arranged at equal intervals along the Y direction. By inserting the peripheral portion of the substrate W into each substrate holding groove, 25 substrates W are held at equal intervals along the Y direction and in a vertical position on the substrate holding portion 413.

[0025] One end of the guide rail 411 extends to the front of the junction area 33 within the first interface 3. Therefore, as described above, substrates can be transferred between the first substrate transfer robot 31 and the second substrate transfer robot 41 within the junction area 33. The other end of the guide rail 411 extends to the front of the standby unit 44. Therefore, the second substrate transfer robot 41 can transfer substrates between the standby unit 44 and any batch processing unit 42. Furthermore, the substrate holding portion 413 of the second substrate transfer robot 41 can approach the cleaning unit 43 to clean the substrate holding portion 413.

[0026] A third substrate transport robot 51 and one or more (e.g., two) substrate transfer units 52 are provided in the second interface 5. When multiple substrate transfer units 52 are provided, they can be stacked one on top of the other.

[0027] The third substrate transport robot 51 takes out the substrates W held by the substrate holder 442 one by one into the immersion tank 441 of the standby unit 44, and after changing the substrate W from a vertical position to a horizontal position, it can be placed on the substrate transfer unit 52.

[0028] The single-wafer processing unit 6 includes: one or more single-wafer liquid processing units (single-wafer processing units) 61; one or more supercritical drying units 62 for supercritical drying of the substrate W processed by the single-wafer liquid processing units 61; and a fourth substrate transport robot 63. When multiple single-wafer liquid processing units 61 and supercritical drying units 62 are provided, for example, they can be stacked one on top of the other. The single-wafer liquid processing unit 61 and the supercritical drying unit 62 are single-wafer processing units that process one substrate W at a time.

[0029] The fourth substrate transport robot 63, for example, includes an end effector capable of moving in the X and Y directions, lifting and lowering in the Z direction, and rotating around a multi-axis drive mechanism 631. The end effector is, for example, a fork-shaped substrate holder 632 capable of holding a substrate. The fourth substrate transport robot 63 can transport substrates in and out between the substrate transfer unit 52 in the second interface 5, the monolithic liquid processing unit 61, the supercritical drying unit 62, and the substrate transfer unit 35 in the first interface 3. The substrate W remains horizontal throughout the transport process by the fourth substrate transport robot 63.

[0030] Any unit known in the technical field of semiconductor manufacturing apparatus can be used as the monolithic liquid processing unit 61. Hereinafter, a configuration example of the monolithic liquid processing unit 61 that can be used in this embodiment will be briefly described with reference to FIG6. The monolithic liquid processing unit 61 includes a rotary chuck 611 capable of holding a substrate W in a horizontal position and rotating it about a vertical axis, and one or more nozzles 612 that eject processing liquid onto the substrate W held and rotated by the rotary chuck 611. The nozzles 612 are supported on arms 613 for moving the nozzles 612. The monolithic liquid processing unit 61 has a liquid receiving cup 614 for collecting processing liquid that spills from the rotating substrate W. The liquid receiving cup 614 has a drain port 615 for discharging the collected processing liquid to the outside of the monolithic liquid processing unit 61, and an exhaust port 616 for discharging the atmosphere inside the liquid receiving cup 614. Clean gas (clean air) is blown downward from the fan filter unit 618 located at the top of the chamber 617 of the monolithic liquid handling unit 61, drawn into the liquid receiving cup 614, and discharged to the exhaust port 616.

[0031] In this embodiment, the fourth substrate transfer robot 63 removes the substrate W from the substrate transfer unit 52 within the second interface 5 and transfers it into the monolithic liquid processing unit 61. In the monolithic liquid processing unit 61, DIW rinsing, IPA replacement, and IPA paddle formation are performed sequentially. In the DIW rinsing, DIW is supplied from the nozzle 612 to the surface of the rotating substrate W, washing away any liquid adhering to the surface of the substrate W. In the IPA replacement, IPA is supplied from the nozzle 612 to the surface of the continuously rotating substrate W, replacing the DIW on the substrate W surface with IPA. In the IPA paddle formation, while continuing to supply IPA from the nozzle 612, the rotation speed of the substrate is significantly reduced, forming a thicker IPA film on the surface of the substrate W, and then the substrate rotation is stopped.

[0032] Any unit known in the technical field of semiconductor manufacturing apparatus can be used as the supercritical drying unit 62. An example of the configuration and operation of the supercritical drying unit 62 that can be used in this embodiment will be briefly described below with reference to FIG7. The supercritical drying unit 62 has a supercritical chamber 621 and a substrate support tray 622 that can move forward and backward relative to the supercritical chamber 621. FIG1 shows the state in which the substrate support tray 622 is withdrawn from the supercritical chamber 621, in which a fourth substrate transfer robot 63 performs substrate W transfer on the substrate support tray 622.

[0033] The substrate W with IPA droplets formed is removed from the monolithic liquid handling unit 61 by the fourth substrate transport robot 63 and placed on the substrate support tray 622 of the supercritical drying unit 62. The substrate support tray 622 is then housed within the ultra-supercritical chamber 621 and sealed by a cover 625 integral with the substrate support tray 622. In this state, supercritical fluid (e.g., supercritical carbon dioxide (CO2)) is supplied from a supercritical fluid supply source (not shown) via supply port 623 into the supercritical chamber 621, flows as indicated by the arrows in the figure, and is discharged from outlet port 624. During the pressurization of the interior of the supercritical chamber 621, CO2 can be supplied via another supply port (not shown) opening towards the lower part of the substrate support tray 622. The IPA on the substrate W is replaced by the supercritical CO2 flowing nearby. After the IPA is replaced by the supercritical CO2, the pressure inside the supercritical chamber 621 is restored to atmospheric pressure. As a result, the supercritical CO2 vaporizes and the surface of the substrate W is dried. This prevents the pattern formed on the surface of substrate W from collapsing and allows substrate W to dry.

[0034] After drying, the substrate is taken out from the supercritical drying unit 62 by the fourth substrate transfer robot 63 and transferred into the substrate transfer unit 35 located in the first interface section 3. The first substrate transfer robot 31 of the first interface section 3 takes out the substrate W from the substrate transfer unit 35 and stores the processed substrate W in the container F placed on the substrate storage platform 221B.

[0035] The container F containing the processed substrate W is placed on the movable stage 211 by the container transport robot 222 of the container storage section 22 and moved to the stage section 21.

[0036] Next, an example of the configuration and function of the batch processing unit 4 (especially its standby unit 44) and the second interface 5 will be described in detail with reference to Figures 2-5 and 8.

[0037] The second substrate transport robot 41 and the third substrate transport robot 51 are described together with the standby unit 44 in Figures 2 and 3.

[0038] The standby unit 44, as described above, has an impregnation tank 441. The impregnation tank 441 has an inner tank 441A for storing impregnation liquid and an outer tank 441B for receiving impregnation liquid overflowing from the inner tank 441A. The impregnation liquid flowing out of the outer tank 441B flows into a circulation line 444 and is discharged onto the substrate W from a nozzle 445 disposed within the inner tank 441A. The nozzle 445 may be a rod-shaped nozzle having outlets arranged at equal intervals along the arrangement direction of the substrate W within the inner tank 441A. The circulation line 444 is provided with a pump for forming a circulating flow, a filter for removing particles, and a temperature regulator, such as a heater, for adjusting the temperature of the impregnation liquid.

[0039] As described above, the standby unit 44 has a substrate holder 442 that holds a substrate within an impregnation tank 441. The substrate holder 442 has a flat base 442A extending in the vertical direction (Z direction) and two sets of support members 442B extending from the base 442A in the horizontal direction (Y direction). Each set of support members 442B has: two support rods 442C, the base ends of which are fixed to the base 442A; and a fixing member 442D that fixes the front ends of the two support rods 442C. A substrate holding groove (not shown) for positioning the substrate W in the Y direction by means of the peripheral portion of the receiving substrate W is formed at equal intervals in the Y direction on each support rod 442C. The substrate holder 442 is capable of holding multiple substrates, for example, 25 substrates W, at equal intervals in the Y direction in a vertical orientation.

[0040] The standby unit 44 has a moving mechanism 446 that can move the substrate holder 442 in the Y and Z directions. The moving mechanism 446 can move the substrate holder 442 between the handover position (indicated by the double-dotted dashed line in FIG2) and the immersion position (indicated by the solid line in FIG3). At the handover position, the substrate can be handed over to the second substrate transfer robot 41. At the immersion position, the held substrate W can be immersed in the immersion liquid stored in the immersion tank 441.

[0041] As shown in Figure 5, the two sets of support members 442B of the substrate holder 442 of the standby unit 44 can pass through the gap between the three substrate holding rods 414 of the substrate holding part 413 constituting the second substrate transfer robot 41. Therefore, by moving the substrate holder 442 (support member 442B) and the substrate holding part 413 (substrate holding rod 414) relative to each other in the Z direction, multiple substrates W can be transferred together between the support member 442B and the substrate holding rod 414.

[0042] The arrows in Figure 5 indicate the relative vertical movement between the support member 442B and the holding rod 413A. When the substrate holding rod 414, indicated by the solid circle in Figure 5, is positioned above the support member 442B, the substrate W held by the support member 442B is held by the substrate holding rod 414. By performing the opposite relative movement, the substrate W held by the substrate holding rod 414 is held by the support member 442B.

[0043] As can be seen from the above description, the configuration of the standby unit 44 is the same as that of batch liquid handling apparatuses known in the art. In other words, the configuration of the batch processing unit 42 in this embodiment can be the same as that of the standby unit 44, and the transfer of substrate W between the batch processing unit 42 and the second substrate transfer robot 41 can also be performed in the same manner. Therefore, the description of the configuration of the batch processing unit 42 is omitted. It should be noted that the main difference between the batch processing unit 42 and the standby unit 44 is that not only the second substrate transfer robot 41, but also the third substrate transfer robot 51 can access the standby unit 44 and the liquid stored in the tank.

[0044] The third substrate transport robot 51 is configured as a monolithic transport robot. The end effector of the third substrate transport robot 51 is composed of a thin-plate substrate holder 511. In one illustrated embodiment, the substrate holder 511 has a base 511A and a pair of elongated front ends 511B connected to the base 511A. Each front end 511B has a dimension that allows insertion between two support rods 442C that can be inserted into each support member 442B constituting the substrate holder 442 (see Figure 4).

[0045] As shown in Figures 2 and 4, the substrate holder 511 has multiple (three in the example) clamping claws 512A and 512B (roughly represented by solid circles in Figure 4). In the illustrated example, a movable clamping claw 512A is provided at the front end of the base 511A of the substrate holder 511, and a fixed clamping claw 512B is provided at the front end of each front end 511B. The clamping claws 512A and 512B have a shape that allows them to engage with the periphery of the substrate W (the area near APEX).

[0046] As shown in Figures 2 and 3, the substrate holder 511 is brought close to the substrate W in the Y direction. With the movable gripper 512A away from the fixed gripper 512B, the movable gripper 512A and the fixed gripper 512B are positioned slightly away from the periphery of the substrate W. From this position, by moving the movable gripper 512A closer to the fixed gripper 512B, the substrate W can be gripped using the movable gripper 512A and the fixed gripper 512B. Next, by moving the substrate holder 511 directly upward (in the positive Z direction), the periphery of the substrate W can be pulled out from the substrate holding groove (not shown) of the support rod 442C of the substrate holder 442, thereby allowing the substrate W to be removed.

[0047] If the third substrate transport robot 51 is configured to satisfy the following functions (1) and (2), it is configured as a multi-axis robot (e.g., having an X-axis, Y-axis, Z-axis and θ-axis) and can be configured as a multi-joint robot. (1) Any substrate W held in the substrate holder 442 within the inner groove 441A is moved in the vertical direction (positive Z direction) while being held by the substrate holder 511, so that it can be removed from the inner groove 441A. (2) It can change the substrate W in the vertical position in the inner groove 441A to the horizontal position and place it on the substrate transfer unit 52. Figures 1 to 3 schematically illustrate the third substrate transport robot 51, which is a multi-joint robot.

[0048] As shown in Figures 2 and 3, a spray nozzle 447 may be provided in the impregnation tank 441. The spray nozzle 447 can be moved along the Y direction by a Y-direction moving mechanism 448 (shown only in Figure 3) to a position slightly above the surface of the impregnation liquid stored in the inner tank 441A. The spray nozzle 447 can spray liquid onto the surface of the substrate W during or immediately after the substrate W is pulled out of the impregnation liquid by the third substrate transport robot 51. The spray nozzle 447 is preferably configured to spray liquid evenly onto the surface of the substrate W. For example, the spray nozzle 447 may be configured as a rod-shaped nozzle with outlets arranged at equal intervals along the X direction. In this case, the spray nozzle 447 is positioned by the Y-direction moving mechanism 448 at a position close to and facing the surface of the substrate W pulled out by the third substrate transport robot 51, and sprays liquid onto the surface of the substrate W.

[0049] The third substrate transfer robot 51, after converting the substrate W taken from the impregnation tank 441 into a horizontal position, moves it into the substrate transfer unit 52. The substrate transfer unit 52 is an intermediary unit that transfers the substrate W between the third substrate transfer robot 51 and the fourth substrate transfer robot 63. An example configuration of the substrate transfer unit 52 is schematically shown in FIG8. The third substrate transfer robot 51, the substrate transfer unit 52, and the fourth substrate transfer robot 63 constitute a transfer system for transferring the substrate W from the batch processing unit 4 (standby unit 44) to the single-wafer processing unit 6.

[0050] The substrate transfer unit 52 has multiple (e.g., three) support pins 521 as substrate support members. A third substrate transfer robot 51 moves the substrate W from the transfer inlet 522 into the substrate transfer unit 52, placing the substrate W horizontally on the support pins 521. A coating liquid nozzle 523 is provided on the top of the substrate transfer unit 52 for dispensing coating liquid onto the surface of the substrate W. The coating liquid nozzle 523 supplies coating liquid in a manner that forms droplets (liquid films) of coating liquid across the entire surface of the substrate W. The coating liquid may be, for example, DIW, but is not limited to this; it may also be a processing liquid for negative zeta potential processing, as described later.

[0051] A liquid film thickness sensor (not shown) or a camera (not shown) is provided at the top of the substrate transfer unit 52. Coating liquid can be supplied to the surface of the substrate W from the coating liquid nozzle 523 only when the liquid film on the surface of the substrate W is about to break due to drying or other reasons. Alternatively, coating liquid can be supplied to the surface of the substrate W from the coating liquid nozzle 523 only when the substrate W has remained in the substrate transfer unit 52 for a sufficiently long time that the surface of the substrate W is likely to dry (meaning at least part of the surface is exposed to the atmosphere). In this case, the residence time of the substrate W in the substrate transfer unit 52 can be timed by a timer. In the above cases, the control device 100 dispenses coating liquid from the coating liquid nozzle 523 to the substrate W based on the detection result of the sensor or camera or the timing result of the timer.

[0052] When the monolithic liquid processing unit 61, which is scheduled to be moved into the substrate W, becomes capable of moving the substrate W, the substrate W is taken out from the loading port 524 and moved into the monolithic liquid processing unit 61 by the fourth substrate transport robot 63. After that, the travel path of the substrate W is as described above.

[0053] Next, the liquids (immersion liquid, spray liquid) supplied by the standby unit 44 to the substrate W and the liquids (coating liquid) supplied by the substrate transfer unit 52 to the substrate W will be described. The following are some potential problems that may occur during the transfer from the batch processing unit 4 to the single-wafer processing unit 6.

[0054] If the substrate W becomes hydrophobic after the final chemical solution treatment in the batch processing unit 4, a portion of the substrate surface may be exposed during the transfer from the batch processing unit 4 to the single-piece processing unit 6 due to liquid loss. Exposure of the substrate surface can lead to pattern collapse or defects such as particles and watermarks on the substrate surface (Problem 1).

[0055] If the substrate W is positively charged after the final chemical solution treatment in the batch processing unit 4, the possibility of particles floating in the liquid adhering to the substrate increases (because the zeta potential of the particles and the zeta potential of the substrate surface are opposite) (Question 2).

[0056] In this embodiment, at least one of the above-mentioned problems 1 and 2 is solved by performing liquid processing in the standby unit 44.

[0057] The liquid treatment used to solve Problem 1 above is a process to hydrophilize the substrate surface (hereinafter referred to as "hydrophilization treatment"). Since the hydrophilization treatment requires a long time, the substrate is immersed in the immersion liquid (treatment liquid for hydrophilization treatment) stored in the immersion tank 441 of the standby unit 44. As the treatment liquid for hydrophilization treatment, any of the following can be used, for example. - SC2 - Ozone water - Hydrogen peroxide water (H₂O₂) - SPM (hydrogen peroxide sulfate) Which of these methods to use can be determined by considering factors such as the processing solution used in the final chemical solution treatment performed in batch processing unit 4 (excluding the DIW rinsing treatment as the final process) and the surface condition of the substrate W after treatment (material of the exposed surface, chemical state (whether the ends have hydrophilic groups, etc.). Please refer to the specific examples of the treatment described later.

[0058] In this embodiment, at least 25 substrates are simultaneously immersed in the hydrophilic treatment solution within the immersion tank 441, and then removed one by one. That is, the immersion time varies significantly between the first and last substrates removed. Therefore, the hydrophilic treatment solution should not etch the substrate surface to a problematic level. From the viewpoint of suppressing etching, the temperature of the hydrophilic treatment solution is preferably room temperature (but not limited to room temperature).

[0059] The liquid treatment used to solve problem 2 above is a treatment in which a liquid (liquid film) capable of making the zeta potential of the substrate surface negative is attached to the surface of the substrate W (hereinafter referred to as "negative zeta potential treatment"). Compared with hydrophilic treatment, negative zeta potential treatment can take effect in a short time. Therefore, it can be carried out by immersing in the immersion liquid (treatment liquid for negative zeta potential treatment) in the immersion tank 441, or by spraying the zeta potential negative potential treatment liquid (treatment liquid for negative zeta potential treatment) onto the substrate surface through the spray nozzle 447.

[0060] For example, any of the following can be used as the treatment solution for negative zeta potential treatment. - Functional water (e.g., DIW (deionized water) containing trace amounts of ammonia) - TMAH (Tetramethylammonium hydroxide) - Organic base solution - Anionic surfactants From the perspective of suppressing etching, the temperature of the processing solution used for negative zeta potential treatment is preferably room temperature (but not limited to room temperature).

[0061] For example, if the final chemical solution treatment performed in the batch processing unit 4 is SC1 treatment (followed by DIW rinsing), the surface of the substrate W can be sufficiently hydrophilized when it is placed in the standby unit 44. In this case, only zeta potential negative treatment can be performed in the standby unit 44. In this case, zeta potential negative treatment can also be performed using the spray nozzle 447. Similarly, in this case, since the substrate W should not be exposed to the atmosphere during standby, it is advisable that the impregnation liquid in the impregnation tank 441 is a suitable non-reactive liquid such as DIW, and the substrate is kept in the impregnation liquid for standby. Of course, zeta potential negative treatment can also be performed using the impregnation liquid (processing liquid for zeta potential negative treatment) in the impregnation tank 441.

[0062] However, even if the surface of the substrate W is hydrophilic when the substrate W is placed in the standby unit 44, the hydrophilic treatment solution can be stored in the immersion tank 441 to further improve the hydrophilicity. Alternatively, a treatment can be performed to maintain at least the hydrophilicity.

[0063] As described above, the hydrophilicity of the substrate W surface and the negative zeta potential of the substrate W surface when leaving the standby unit 44 can provide the following advantageous effects.

[0064] Since the surface of the substrate W remains hydrophilic when it leaves the standby unit 44, liquid loss (disappearance of a portion of the liquid film on the entire substrate surface) can be prevented when the substrate W is pulled out of the impregnation liquid in the impregnation tank 441. Furthermore, during the transport of the substrate W from the batch processing unit 4 to the single-piece processing unit 6, liquid shortage (loss of liquid) on the surface of the substrate W can be prevented. Therefore, defects such as particles or watermarks that may appear on the surface of the substrate W, or pattern collapse, which are exposed to the atmosphere, can be prevented.

[0065] From the opposite perspective, according to the above embodiment, even if the transport distance or required transport time from the batch processing unit 4 to the single-wafer processing unit 6 is slightly longer, there will be no problem. This means that an optimal layout can be adopted for each of the batch processing unit 4 and the single-wafer processing unit 6. In other words, there is no need to use an unreasonable layout to shorten the transport distance or required transport time. Moreover, in many cases, the processing schedules of batch processing and single-wafer processing are difficult to match perfectly, and some waiting time needs to be set to transport the substrate W into the single-wafer processing unit. According to the above embodiment, since it is difficult for liquid to be lost on the surface of the substrate W, it is unlikely that there will be a problem even if some waiting time is set. Therefore, the flexibility of setting the transport schedule and processing schedule is improved. In addition, when a transfer unit 52 with a coating liquid nozzle 523 is provided between the batch processing unit 4 and the single-wafer processing unit 6, the possibility of liquid loss on the surface of the substrate W can be further reduced during the transport of the substrate W from the batch processing unit 4 to the single-wafer processing unit 6.

[0066] Furthermore, since the zeta potential of the substrate W surface is negative when it leaves the standby unit 44, particles contained in the liquid film on the substrate W surface can be prevented or significantly suppressed from adhering to the substrate W surface during the transfer of the substrate W from the batch processing unit 4 to the single-piece processing unit 6. This also eliminates the need for unreasonable layouts to shorten the transfer distance or required transfer time, and improves the flexibility of setting transfer and processing schedules (particle adhesion caused by zeta potential tends to increase over time).

[0067] As described above, according to this embodiment, when the substrate W is transferred from the batch processing unit 4 to the single-piece processing unit 6, the deterioration of the surface condition of the substrate W can be prevented.

[0068] The following describes a specific example of a combination of the processing performed in each processing unit of the batch processing section 4 and the hydrophilic treatment and / or negative Zeta potential treatment performed in the standby unit 44.

[0069] <Concrete example 1> In Specific Example 1, in the batch processing unit 4, as shown in FIG. 9, the SiN film of the substrate W having a 3D-NAND SiO2 / SiN stacked structure is selectively etched (the left side of the figure shows the etching, and the right side shows the result after etching). In this case, firstly, the SiN film is selectively etched by high-temperature phosphoric acid in the first batch processing unit 42, and then DIW rinsing is performed in the second batch processing unit 42. Next, etching residue removal based on SC1 is performed in the third batch processing unit 42, and finally DIW rinsing is performed in the fourth batch processing unit 42. Afterwards, the substrate is transported to the standby unit 44 and immersed in the standby liquid, and then picked up one by one by the third substrate transport robot 51 and transported to the single-wafer processing unit 6, where drying is performed in the order described above.

[0070] In this specific example 1, the surface of the processed substrate (including the inner surface of the recess) is mostly hydrophilic SiO2, and the hydrophilicity is further improved by SC1 treatment in the third batch processing unit 42, eliminating the need for hydrophilization treatment in the standby unit 44. Therefore, the standby unit 44 only needs to perform zeta potential negative treatment. For example, the substrate can also be immersed in an immersion tank 441 storing a treatment solution (e.g., weakly alkaline functional water) for zeta potential negative treatment. In this case, the spray nozzle 447 can be omitted. The treatment solution for zeta potential negative treatment can also be supplied to the substrate W in the substrate transfer unit 52.

[0071] <Concrete example 2> In specific example 2, in batch processing unit 4, as shown in FIG10, a portion of the SiN film on the substrate W with a Si / SiO2 / SiN stacked structure constituting the unit transistor module of 3D-DRAM is selectively etched (the left side of FIG10 is before etching, and the right side is after etching). In this case, firstly, the SiN film is selectively etched by high-temperature phosphoric acid in the first batch processing unit 42, and then DIW rinsing is performed in the second batch processing unit 42. Afterwards, the substrate is transported to the standby unit 44 and immersed in the standby solution, and is picked up one by one by the third substrate transport robot 51 and transported to the single-wafer processing unit 6, where it is dried in the order described above. Furthermore, after the processing in the second batch processing unit 42, the etching residue removal process based on SC1 is performed in the third batch processing unit 42, and finally the DIW rinsing process is performed in the fourth batch processing unit 42. However, it is assumed here that such processing is not performed.

[0072] In specific example 2, hydrophobic Si, hydrophilic SiO2, and semi-hydrophobic SiN are mixed on the surface of the treated substrate (including the surface inside the recess). In fact, the hydrophobic Si makes the entire surface of the substrate appear hydrophobic to semi-hydrophobic. Therefore, it is in a state where liquid loss is likely to occur. Therefore, a hydrophilization treatment is performed in the standby unit 44. Specifically, for example, a hydrophilization treatment solution (e.g., ozone water) can be stored in the immersion tank 441, and the substrate W can be immersed in it.

[0073] <Concrete example 3> Specific Example 3 is a variation of Specific Example 2, and the structure of the substrate to be etched is the same as in Specific Example 2. That is, SiN is also exposed on the surface of the substrate W (including the surface of the recesses). Since the surface of SiN is DIW (pH 6-7) and the surface potential is close to neutral, it becomes a situation where particles are easily adsorbed. Therefore, in order to make the potential of the SiN surface and the potential of the particles have the same sign and repel each other, a zeta potential negative treatment is performed in the standby unit 44. The zeta potential negative treatment can be performed by spraying a treatment solution for zeta potential negative treatment onto the substrate W from the spray nozzle 447. Both hydrophilization treatment and zeta potential negative treatment can be performed in the standby unit 44. In this case, it is preferable to perform hydrophilization treatment in the immersion tank 441 and zeta potential negative treatment by spray nozzle 447. If hydrophilization treatment is not performed in the standby unit 44, zeta potential negative treatment can be performed in the immersion tank 441.

[0074] Next, another embodiment of liquid processing that can be performed in the standby unit 44 will be described. This other embodiment solves the problems that may occur due to the substrate W remaining in the impregnation tank 441 for a long time.

[0075] After multiple substrates W (e.g., 25 or 50) are placed into the impregnation tank 441 of the standby unit 44, the substrates W are removed one by one from the impregnation tank 441 and transported to the single-wafer processing unit 6. The residence time of the first substrate W removed from the impregnation tank 441 and the last substrate W removed from the impregnation tank 441 is significantly different (e.g., several hours). When the impregnation solution is DIW, the dissolved oxygen in the DIW may oxidize or dissolve the surface of the substrate W (e.g., the bare silicon constituting the substrate W, or the metal layer exposed on the surface of the substrate W, such as tungsten wiring), which was confirmed by the following two experiments.

[0076] [Experiment 1] The bare silicon substrate was cleaned with a DHF chemical solution to remove the native oxide film, followed by DIW rinsing. Then, the bare silicon substrate was immersed in an immersion tank containing DIW (dissolved oxygen concentration (DO) of approximately 5000 ppb). This immersion tank had a configuration essentially the same as immersion tank 441 shown in Figure 11, and experiments were conducted. The thickness of the native oxide film on the surface of the bare silicon substrate was approximately 4 Å without DIW immersion (immediately after DIW rinsing), approximately 6.4 Å after 3 hours of DIW immersion, and approximately 7 Å after 5 hours of DIW immersion. This shows that the native oxide film gradually grows when the bare silicon is immersed in DIW for a prolonged period. Furthermore, as described in Configuration Example 1 below, by continuously supplying DIW with low DO to immersion tank 441 at a low flow rate (e.g., approximately 1~2 L / min), DIW with a DO of approximately 5000 ppb can be obtained.

[0077] The bare silicon substrate was cleaned with DHF chemical solution to remove the native oxide film, followed by DIW rinsing, and finally dried. It was then placed in a FOUP (substrate transport container). The thickness of the native oxide film on the surface of the bare silicon substrate was approximately 4 Å immediately after placement in the FOUP, and approximately 4.8 Å after 6.2 hours.

[0078] As can be seen from the above, compared with the case stored in FOUP, immersion in DIW (DO is about 5000 ppb) promotes the growth of natural oxide film.

[0079] [Experiment 2] Using the same immersion bath as in Experiment 1, experiments were conducted to immerse a substrate with a tungsten film on its surface in DIW (DO approximately 5000 ppb). When the DIW immersion time was 3 hours, the reduction in tungsten film thickness was approximately 1.5–2.5 Å; when the DIW immersion time was 5 hours, the reduction was approximately 2.5–4.2 Å. It can be seen that prolonged immersion in DIW leads to a non-negligible dissolution of the tungsten film.

[0080] The inventors believe that the dissolution of the tungsten film is caused by the following reaction. Oxidation As oxidation proceeds further, WO2 is transformed into WO3. <Dissolve>

[0081] DIW supplied as a power source for the factory typically has a dissolved oxygen concentration (DO) of approximately 5 ppb. If DIW with such a low DO is stored in and placed in the impregnation tank 441, oxygen contained in the air surrounding the impregnation tank 441 will dissolve into the DIW, and the DO may increase to over 10,000 ppb. Furthermore, when DIW overflows from the impregnation tank 441 and is circulated back to the impregnation tank 441, it is believed to promote the tendency for oxygen to dissolve in the DIW. Therefore, DIW with a higher dissolved oxygen content can be obtained through oxidation or dissolution (metal loss) caused by the aforementioned mechanism. The configuration of the standby unit 44, which can solve this problem, will be described below with reference to Figures 11 to 14.

[0082] [Example 1] Example 1 of the configuration of the standby unit 44 and the immersion tank 441 is described with reference to FIG11. The configuration of the standby unit 44 and the immersion tank 441 is also shown in FIG2. The same components as those shown in FIG2 are marked with the same symbols.

[0083] A liquid supply nozzle 74 for supplying DIW is installed in the inner tank 411A of the impregnation tank 441. DIW is supplied to the liquid supply nozzle 74 via a liquid supply line 72 connected upstream to the DIW supply source 71, which serves as the factory power source. A flow regulating unit 73 is installed in the liquid supply line 72. The flow regulating unit 73 may be composed of, for example, a single on / off valve, or a combination of an on / off valve, a flow control valve, a flow meter, etc.

[0084] Typically, low-DO (e.g., less than 5 ppb) DIW is supplied by a DIW supply source that serves as a factory power source in the semiconductor device manufacturing plant. Therefore, it is usually not necessary to provide a dedicated low-DO DIW supply device to achieve Configuration Example 1. However, depending on the circumstances, a dedicated low-DO DIW supply device for the substrate processing system 1 may be provided.

[0085] A DO sensor 75 is provided in the inner tank 411A of the impregnation tank 441 for detecting the DO value of the DIW stored in the inner tank 411A.

[0086] A drain line 76 is connected to the bottom of the outer tank 411B of the impregnation tank 441. The drain line 76 is connected to the factory waste liquid system. Multiple drain lines 76 can be installed at different locations in the outer tank 411B.

[0087] The function of Example 1 is explained. After final batch processing (e.g., rinsing after chemical solution treatment), multiple substrates W, for example 25, are transferred from the batch processing unit 42 (where the substrates W underwent final processing) to the standby unit 44 by a second substrate transfer robot 41, and then placed together into the impregnation tank 441 (inner tank 441A). Subsequently, a third substrate transfer robot 51 removes the substrates W one by one from the inner tank 441A. If the DIW in the inner tank 441A is left in a state of retention, oxygen in the air surrounding the inner tank 441A will dissolve in the DIW, and the DO value of the DIW will increase over time.

[0088] To prevent the DO value from exceeding a predetermined threshold and to suppress DIW consumption, feedback control is performed, for example, under the control of the control device 100 (see Figure 1). Here, the DO value threshold refers to the DO value at which the substrate W, which is placed in the impregnation tank 441 (inner tank 441A) and is ultimately removed from the inner tank 441A, is not oxidized to the point of causing problems, for example, 100 ppb. For example, the threshold may be decreased (increased) as the longest residence time of the substrate W in the inner tank 441A increases (decreases).

[0089] Feedback control can be performed by controlling the supply of low-DO DIW from the DIW supply source 71 to the impregnation tank 441 (inner tank 441A) via the liquid supply nozzle 74, based on the deviation between the DO value (measured value) detected by the DO sensor 75 and the target DO value, for example, 100 ppb. Since the inner tank 441A is normally full of DIW, the same amount of low-DO DIW supplied from the liquid supply nozzle 74 will overflow from the inner tank 441A into the outer tank 441B. Thus, a portion of the DIW with relatively high DO is replaced by DIW with relatively low DO (e.g., less than 5 ppb). As a result, the DO of the DIW in the inner tank 441A can be reduced. As the supply flow rate of low-DO DIW increases, the DO of the DIW in the inner tank 441A can be rapidly reduced.

[0090] Feedback control can be, for example, PID control. In this case, the supply flow rate of low-DO DIW to the impregnation tank 441 (inner tank 441A) can be controlled by the duty cycle control of the on / off valve provided in the flow adjustment unit 73. If the flow adjustment unit 73 includes a flow control valve with a stepless variable opening, the opening of the flow control valve can be controlled by PID control to control the supply flow rate of low-DO DIW.

[0091] Feedback control could be, for example, HIGH / LOW control (binary control). In this case, when the DO value (measured value) detected by the DO sensor 75 is below a predetermined threshold (e.g., 100 ppb), a low-DO DIW is supplied to the impregnation tank 441 (inner tank 441A) at a predetermined low flow rate (LOW) (e.g., about 1~2 L / min). Then, when the DO value (measured value) is about to exceed the predetermined threshold due to oxygen dissolved in the DIW, the low-DO DIW is supplied to the impregnation tank 441 at a high flow rate (HIGH) (e.g., 30 L / min or more). The supply of high-flow-rate DIW can be carried out at a predetermined time determined through prior experimentation. Alternatively, the supply of high-flow-rate DIW can continue until the DO value (measured value) detected by the DO sensor 75 drops to a predetermined value (e.g., about 50 ppb).

[0092] If the DIW in the inner tank 441A is placed in a stagnant state before the substrate W is immersed in the impregnation tank 441 (inner tank 441A), the DO will rise over time. It may take nearly 10 minutes (depending on the capacity of the inner tank 441A) to reduce the DO from an excessively high state (e.g., about 10,000 ppb) to the aforementioned threshold (e.g., 100 ppb).

[0093] Therefore, even when the impregnation tank 441 (inner tank 441A) is in standby mode (without substrate W), it is preferable to supply low-DO DIW at a low flow rate (e.g., about 1~2 L / min), thereby suppressing DO to, for example, about 5000 ppb. Thus, the time required to reduce DO to the aforementioned threshold (e.g., 100 ppb) (depending on the capacity of the inner tank 441A) is approximately 2 to 4 minutes (when the low-DO DIW supply flow rate is about 40~80 L / min). This further suppresses oxidation damage to the substrate W.

[0094] When the above-mentioned HIGH / LOW control (binary control) is performed during feedback control, a low-DO DIW can be supplied with low flow (LOW) in all time periods (including the standby time period) without supplying a high-flow (HIGH) and low-DO DIW.

[0095] The aforementioned feedback control can begin either after the substrate W is immersed in the immersion bath 441 (inner bath 441A) or before the substrate W is immersed in the inner bath 441A. In the former case, the consumption of low-DO DIW can be reduced. In the latter case, oxidation damage to the substrate W can be further suppressed. Even if the substrate W is immersed in DIW with a DO of about 5000 ppb for several minutes, problematic oxidation will not occur in most cases. Therefore, it is considered that there is no problem even if the feedback control is started after the substrate W is immersed in the immersion bath 441 (inner bath 441A).

[0096] In the configuration example shown in Figure 11, low-DO DIW is supplied to the inner tank 441A, and the DIW in the inner tank 441A overflows into the outer tank 441B. Oxygen dissolves in the DIW stored in the inner tank 441A at the liquid surface. Therefore, from the viewpoint of reducing DO, the overflow method of DIW near the liquid surface flowing out to the outer tank 441B is the most preferred.

[0097] However, the method of draining DIW from the impregnation tank 441 (inner tank 441A) is not limited to overflow. Any means to achieve this is optional, as long as the relatively high DO DIW in the inner tank 441A can be replaced by relatively low DO DIW. For example, a drain line can be connected to the impregnation tank 441 (inner tank 441A) to drain the DIW. Furthermore, if the circulation line 444 shown in FIG. 2 is connected to the impregnation tank 441, a drain line can be connected midway through the circulation line from which the DIW can be drained.

[0098] As shown in Figure 2, when the DIW overflows from the inner tank 441A of the impregnation tank 441 into the outer tank 441B and circulates back to the inner tank 441A via the circulation pipeline 444, it promotes the dissolution of oxygen in the DIW. Therefore, this configuration is less desirable if only the reduction of dissolved oxygen is considered. However, if the DIW is circulated, the temperature of the DIW can be easily adjusted; if this is a priority, DIW circulation can be implemented.

[0099] As is well known, no oxide film growth was observed after more than 1000 minutes when bare silicon was immersed in a DIW with a DO of 40 ppb. Therefore, the application of Configuration Example 1 suggests that silicon oxidation could be suppressed. In fact, even when the DO was suppressed to 100 ppb using the aforementioned feedback control, no problematic oxide film growth was observed. By controlling DO using the aforementioned feedback control, the consumption of low-DO DIWs can be suppressed, and silicon oxidation can also be suppressed.

[0100] [Example 2] Example 1 of the configuration of the standby unit 44 and the impregnation tank 441 will be described with reference to FIG12. In FIG12, the same reference numerals are used to denote the same components as those shown in FIG11. The configuration of FIG12 is different from that of FIG11, except that one or more (two in the example) bubbling nozzles 80 are provided at the bottom of the impregnation tank 441 (inner tank 441A). The bubbling nozzles 80 can be formed, for example, by a pipe having multiple gas outlets arranged along the arrangement direction of the substrate W. N2 gas is supplied to the bubbling nozzles 80 from a nitrogen (N2) gas supply source 81, for example, a factory power source, via a gas supply line 82. A flow adjustment unit 83 is provided in the gas supply line 82. The flow adjustment unit 83 can be composed of a single on / off valve, or it can be composed of a combination of an on / off valve, a flow control valve, a flow meter, etc.

[0101] Nitrogen (N₂) gas is expelled from the bubbling nozzle 80, causing tiny bubbles originating from the N₂ gas to rise and be distributed substantially uniformly within the DIW in the inner tank 441A. By bubbling with N₂ gas, dissolved oxygen can be expelled from the DIW, resulting in a reduction in the DO value of the DIW.

[0102] Preferably, the bubbling of N2 gas is performed continuously, at least while the substrate W is contained in the impregnation tank 441 (inner tank 441A). Alternatively, the bubbling of N2 gas can be started before the substrate W is immersed in the impregnation tank 441.

[0103] The configuration shown in Figure 12, Example 2, adds N2 gas bubbling to Configuration 1, thus enabling more effective reduction of dissolved oxygen in the DIW. In this case, feedback control of the DO value is performed solely by controlling the supply amount (overflow amount) of the DIW with low DO, allowing continuous N2 gas bubbling under certain conditions during the period when the substrate W is housed in the impregnation tank 441 (inner tank 441A). To adjust the DO value, the N2 gas bubbling conditions (e.g., N2 gas emission amount) can be changed based on the detection value of the DO sensor 75.

[0104] The DO value can also be controlled solely by bubbling N2 gas. In this case, for example, based on the detection value of DO sensor 75, the bubbling conditions of N2 gas (e.g., the flow rate of N2 gas) can be controlled to obtain the desired DO value. In this case, for example, to prevent DIW from remaining in the impregnation tank 441 (inner tank 441A), DIW can be continuously supplied from the liquid supply nozzle 74 at a small flow rate.

[0105] An experiment was conducted to confirm the change in dissolved oxygen (DO) by bubbling N2 gas in DIW stored in impregnation tank 441. However, instead of the impregnation tank shown in Figure 12, the impregnation tank with a circulation line (444) shown in Figure 2 was used. That is, while continuously overflowing DIW from the inner tank (441A) to the outer tank (441B), the DIW was circulated in the circulation line, and N2 gas bubbling was performed. Although the DO of the DIW was approximately 7000 ppb before the start of N2 gas bubbling, the DO dropped to approximately 1000 ppb after about 20 minutes of N2 gas bubbling. Thereafter, even with continued N2 gas bubbling, the DO hardly changed. In this experiment, the DO only decreased to approximately 1000 ppb. The inventors believe that this is because more oxygen dissolved in the DIW was released when it overflowed from the inner tank to the outer tank. Therefore, the inventors believe that by not returning the overflowing DIW to the impregnation tank, the DO value after N2 gas bubbling can be significantly reduced.

[0106] [Example 3] FIG13 will be used to describe a configuration example 3 of the standby unit 44 and the immersion tank 441. In FIG13, components that are the same as those shown in FIG11 and FIG12 are marked with the same symbols. In this configuration example 3, the bubbling nozzle 80 is connected to the CO2 supply source 84, and CO2 (carbon dioxide) gas is discharged from the bubbling nozzle 80. By bubbling CO2 gas, dissolved oxygen is discharged from the DIW, thereby reducing DO.

[0107] When CO2 gas is bubbled, not only does the reduction in dissolved oxygen (DO) make oxidation difficult, but the decrease in pH of the DIW also inhibits corrosion of the metal film (e.g., a W (tungsten) film). In this case, in addition to the DO sensor 75, a conductivity meter 85 is provided to measure the conductivity of the DIW in the impregnation tank 441 (inner tank 441A), and based on the detection value of the conductivity meter 85, the bubbling conditions of the CO2 gas (e.g., the amount of CO2 gas emitted) can be controlled to obtain the desired conductivity (e.g., 1 μS / cm or higher). When CO2 gas is dissolved in the CO2 water of the DIW, pH and conductivity have a one-to-one correspondence, so pH (the amount of dissolved CO2) can be managed by the conductivity meter 85.

[0108] Preferably, CO2 gas bubbling continues at least while the substrate W is contained in the impregnation tank 441 (inner tank 441A). Alternatively, CO2 gas bubbling can begin before the substrate W is immersed in the impregnation tank 441.

[0109] During CO2 gas bubbling, low-DO DIW can be supplied in parallel from the liquid supply nozzle 74. However, if the pH adjustment function is important through CO2 gas bubbling, it is preferable to supply DIW at a low flow rate. If CO2 gas bubbling is performed to remove dissolved oxygen from the DIW, the DIW supply flow rate is arbitrary. In this case, the DO of the DIW in the impregnation tank 441 (inner tank 441A) can be controlled primarily by supplying low-DO DIW from the liquid supply nozzle 74, while CO2 gas bubbling is performed as a supplement.

[0110] The DO value or conductivity can also be controlled solely by CO2 gas bubbling. In this case, for example, based on the detection value of the DO sensor 75 or the conductivity meter 85, the conditions of CO2 gas bubbling (e.g., the amount of CO2 gas emitted) can be controlled to obtain the desired DO value or conductivity. Alternatively, if the amount of dissolved CO2 gas in the DIW increases, both the DO value and conductivity will decrease. Since there is a positive correlation between DO value and conductivity, the conditions of CO2 gas bubbling can be controlled based on only one of the DO value and conductivity. However, in this case, it is preferable to monitor the other of the DO value and conductivity. In this situation, it is less desirable for the DIW to remain in the impregnation tank 441 (inner tank 441A), so it is preferable, for example, to continue supplying the DIW at a small flow rate from the liquid supply nozzle 74.

[0111] Alternatively, instead of bubbling CO2 gas within the impregnation tank 441 (inner tank 441A), CO2 water can be generated outside the inner tank 441A and supplied to the inner tank 441A via the liquid supply line 72 and the liquid supply nozzle 74. Known CO2 water generation devices can be used to generate CO2 water outside the inner tank 441A. Alternatively, a hollow fiber membrane module installed in the liquid supply line 72 can be used to dissolve CO2 in DIW supplied from a DIW supply source and supply it to the inner tank 441A.

[0112] When CO2 water is stored in the impregnation tank 441 (inner tank 441A), CO2 will be released into the air surrounding the inner tank 441A, thus reducing the CO2 concentration of the CO2 water. When CO2 water is supplied from outside the inner tank 441A, in order to maintain the CO2 concentration of the CO2 water stored in the impregnation tank 441 within the desired range, new CO2 water can be supplied into the inner tank 441A from the liquid supply nozzle 74. Then, the CO2 water in the inner tank 441A is discharged into the outer tank 441B by overflow. The supply of new CO2 water can be adjusted by feedback control based on the deviation between the detected value of the conductivity meter 85 and the target value (e.g., 0.5 MΩ·cm). As described in Configuration Example 1, feedback control can be performed by PID control or HIGH / LOW control (binary control).

[0113] [Example 4] Example 4 of the configuration of the standby unit 44 and the immersion tank 441 will be described with reference to FIG14. In FIG14, the same components as those shown in FIG11 are marked with the same symbols. In this example 4, hydrogen water (H2-DIW) is supplied from the hydrogen water supply source 90 to the liquid supply nozzle 74 via the liquid supply line 72. An ORP sensor 92 for measuring the oxidation-reduction potential (ORP) of the hydrogen water (H2 water) is provided inside the immersion tank 441 (inner tank 441A). As the hydrogen water supply source 90, a commercially available hydrogen water supply device can be used. If the hydrogen water supply source 90 is supplied as a factory power source, it can be used.

[0114] The hydrogen-water supplied from hydrogen water supply source 90 can be obtained by dissolving hydrogen in DIW at a concentration of approximately 1-2 ppm. The redox potential of pure water is approximately +700 mV, while the redox potential of hydrogen-water with a hydrogen concentration of 1-2 ppm is approximately -200 mV to -300 mV. By lowering the redox potential in this way, oxidation can be suppressed, and corrosion of metal films (such as W (tungsten) films) can be inhibited. Furthermore, since the hydrogen water production process also reduces DO, oxidation is also suppressed.

[0115] If hydrogen water is stored and placed in impregnation tank 441 (inner tank 441A), hydrogen will be released into the air surrounding impregnation tank 441, causing a decrease in the hydrogen concentration in the hydrogen water. To maintain the hydrogen concentration of the hydrogen water stored in impregnation tank 441 within the desired range, fresh hydrogen water can be supplied to the inner tank 441A from the liquid supply nozzle 74. The hydrogen water in the inner tank 441A can be discharged to the outer tank 441B by overflow. The supply of fresh hydrogen water can be adjusted by feedback control based on the deviation between the detected value of ORP sensor 92 and the target value (e.g., -200mV). As described in Configuration Example 1, feedback control can be performed by PID control or HIGH / LOW control (binary control).

[0116] The following describes the experiments conducted to confirm the effects of CO2 water and hydrogen water. The following processes were performed sequentially while a bare silicon wafer was held and rotated by a wafer chuck. (1) DHF (HF:DIW=1:100) cleaning treatment: 25℃, 60 seconds (2) CO2 water rinse: 30 seconds (3) Rotary drying: 40 seconds (4) Supply various test solutions (CO2 water, hydrogen water, DIW (27℃, DO approx. 5ppb)): 60 seconds (5) Rotary drying: 40 seconds After the completion of projects (3) and (5), the thickness of the oxide film was measured using a spectrophotometer. The thickness of the oxide film after the completion of project (3) is 2.669 Å. When CO2 water is used in project (4), the thickness of the oxide film after project (5) is 2.608 Å. When hydrogen water is used in process (4), the thickness of the oxide film after process (5) is 3.263 Å. When DIW is used in process (4), the thickness of the oxide film after process (5) is 4.201 Å. As can be seen from the above, immersion in CO2 water and hydrogen water is more effective in inhibiting the growth of natural oxide film compared to immersion in DIW.

[0117] When using the above-described configuration examples 1 to 4, a spray nozzle 447 (see Figures 2 and 3) can also be used to supply the substrate W taken out from the immersion tank 441 with a hydrophilic treatment solution or a zeta potential negative treatment solution.

[0118] In the above-described configuration examples 1 to 4, after a series of processes are completed in the batch processing section, it is beneficial for substrate W whose surface (including the surface within the recess of the pattern) exposes materials that cause oxidation problems (e.g., silicon (Si) and / or materials that cause dissolution (metal loss) problems (e.g., tungsten (W), molybdenum (Mo), ruthenium (Ru) and the like).

[0119] The following uses the Pourbaix diagram in Figure 15 to briefly explain why CO2-water and hydrogen-water solutions do not readily lead to tungsten metal loss. As can be seen from the tungsten dissolution mechanism described above, the environment must make it difficult for WO4²⁻ (in an ionic state) to form. In CO2-water, the combination of redox potential (vertical axis of the Pourbaix diagram) and pH value lies in the region where H₂WO₄²⁻ is stable. Therefore, both DIW and hydrogen-water (H₂-DIW) are in the region where WO₄²⁻ is stable. However, the redox potential of hydrogen-water is lower than that of DIW, thus tungsten is less likely to dissolve.

[0120] It should be considered that the embodiments disclosed herein are exemplary in all respects, not restrictive. The aforementioned embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended patent applications.

[0121] The substrate is not limited to semiconductor wafers, but can also be other substrates used to manufacture semiconductor devices, such as glass substrates, ceramic substrates, etc.

[0122] W: substrate 4: Batch Processing Department 42: Batch processing unit 44: Standby section (standby unit) 441: Impregnation tank 51, 63: Conveying System 51: First substrate transport unit (third substrate transport robot) 6: Single-chip processing unit 61, 62: Single-chip processing unit

Claims

1. A substrate processing apparatus comprising: a batch processing unit having a plurality of batch processing units, each of the batch processing units having a processing tank for storing a processing liquid, and configured to immerse a plurality of substrates in the processing liquid stored in the processing tank to perform liquid processing on the plurality of substrates simultaneously; a single-substrate processing unit having a single-substrate processing unit for processing the plurality of substrates processed by the batch processing unit one by one; a standby unit having an immersion tank for storing an immersion liquid, and standing by immersing the plurality of substrates processed by the batch processing unit in the immersion liquid; and a transfer system for transferring the plurality of substrates from the standby unit to the single-substrate processing unit, and comprising a first substrate transfer unit for removing the plurality of substrates immersed in the immersion liquid in the immersion tank one by one from the immersion liquid; the standby unit being configured to perform at least one of a first liquid processing and a second liquid processing on the substrates. The aforementioned first liquid treatment is a liquid treatment that makes the surface of the aforementioned substrate hydrophilic, or a liquid treatment that increases or maintains the hydrophilicity of the surface of the aforementioned substrate. The aforementioned second liquid treatment is a liquid treatment that makes the zeta potential of the surface of the aforementioned substrate negative.

2. A substrate processing apparatus comprising: a batch processing unit having a plurality of batch processing units, each of the batch processing units having a processing tank for storing a processing liquid, and configured to immerse a plurality of substrates in the processing liquid stored in the processing tank to perform liquid processing on the plurality of substrates simultaneously; a single-substrate processing unit having a single-substrate processing unit for processing the plurality of substrates processed by the batch processing unit one by one; a standby unit having an immersion tank for storing an immersion liquid, and standing by immersing the plurality of substrates processed by the batch processing unit in the immersion liquid; and a transfer system for transferring the plurality of substrates from the standby unit to the single-substrate processing unit, and comprising a first substrate transfer unit for removing the plurality of substrates immersed in the immersion liquid in the immersion tank one by one from the immersion liquid; the standby unit being configured to perform at least one of a first immersion process and a second immersion process on the substrates. The aforementioned first immersion process is a liquid process in which the aforementioned substrate is immersed in water, which is the aforementioned immersion solution, and the aforementioned immersion solution is controlled so that the dissolved oxygen concentration stored in the aforementioned immersion tank is below a predetermined value. The aforementioned second immersion process is a liquid process in which the aforementioned substrate is immersed in hydrogen water or CO2 water, which is the aforementioned immersion solution, stored in the aforementioned immersion tank.

3. The substrate processing apparatus of claim 1, wherein the aforementioned standby unit is configured to perform both the aforementioned first liquid processing and the aforementioned second liquid processing, wherein the aforementioned first liquid processing is performed by immersing the aforementioned plurality of substrates in a first processing liquid stored in the aforementioned immersion tank as the aforementioned immersion liquid, wherein the aforementioned first processing liquid is a liquid capable of making the surface of the aforementioned substrate hydrophilic, or capable of increasing or maintaining the hydrophilicity of the surface of the aforementioned substrate, wherein the aforementioned standby unit further comprises a processing liquid nozzle, and wherein the aforementioned second liquid processing is performed by supplying the substrate with a second processing liquid capable of making the zeta potential of the surface of the aforementioned substrate negative when the aforementioned substrate is removed from the aforementioned immersion liquid by the aforementioned substrate conveying unit or immediately after removal.

4. The substrate processing apparatus of claim 1, wherein the aforementioned standby unit is configured to perform the aforementioned first liquid processing, wherein the aforementioned first liquid processing is performed by immersing the aforementioned plurality of substrates in a first processing liquid stored in the aforementioned immersion tank as the aforementioned immersion liquid, wherein the aforementioned first processing liquid is a liquid capable of making the surface of the aforementioned substrates hydrophilic, or capable of increasing or maintaining the hydrophilicity of the surface of the aforementioned substrates.

5. The substrate processing apparatus of claim 1, wherein the aforementioned standby unit is configured to perform the aforementioned second liquid processing, wherein the aforementioned second liquid processing is performed by immersing the aforementioned plurality of substrates in a second processing liquid stored in the aforementioned immersion tank as the aforementioned immersion liquid, and the aforementioned second processing liquid is a liquid capable of making the zeta potential of the aforementioned substrate surface negative.

6. The substrate processing apparatus of claim 1, wherein the aforementioned standby unit is configured to perform the aforementioned second liquid processing, the aforementioned immersion tank stores pure water, the aforementioned standby unit further has a processing liquid nozzle, and the aforementioned second liquid processing is performed by supplying a second processing liquid capable of making the zeta potential of the aforementioned substrate surface negative when the substrate is removed from the aforementioned immersion liquid by the aforementioned first substrate conveying unit or immediately after removal.

7. The substrate processing apparatus of claim 3 or 4, wherein the aforementioned first processing liquid is ozone water, SC2, SPM or hydrogen peroxide water.

8. The substrate processing apparatus of any one of claims 3, 5, or 6, wherein the aforementioned second processing liquid is an alkaline liquid.

9. The substrate processing apparatus of claim 8, wherein the aforementioned alkaline liquid is functional water containing ammonia, TMAH (tetramethylammonium hydroxide), or an organic alkaline solution.

10. The substrate processing apparatus of any one of claims 3, 5, or 6, wherein the aforementioned second processing liquid is an anionic surfactant.

11. The substrate processing apparatus of claim 2, wherein the aforementioned standby unit is configured to perform the aforementioned first immersion process, wherein the aforementioned first immersion process is performed by immersing the aforementioned plurality of substrates in pure water with a dissolved oxygen concentration of 100 ppb or less stored in the aforementioned immersion tank.

12. The substrate processing apparatus of claim 11, wherein the aforementioned standby unit is provided with a bubbling nozzle that emits gas in the form of bubbles to remove oxygen dissolved in the pure water stored in the aforementioned impregnation tank.

13. The substrate processing apparatus of claim 12, further comprising: a dissolved oxygen concentration sensor for measuring the dissolved oxygen concentration in the pure water stored in the aforementioned impregnation tank; and a control unit for controlling the gas ejection action from the aforementioned bubbling nozzle to maintain the dissolved oxygen concentration of the pure water stored in the aforementioned impregnation tank below 100 ppb.

14. The substrate processing apparatus of claim 11, wherein the aforementioned standby unit is provided with a low dissolved oxygen concentration pure water supply device for supplying low dissolved oxygen concentration pure water, i.e., pure water with a dissolved oxygen concentration of less than 100 ppb, to the pure water stored in the aforementioned impregnation tank, such that a portion of the pure water stored in the aforementioned impregnation tank is replaced by the supplied low dissolved oxygen concentration pure water.

15. The substrate processing apparatus of claim 14, further comprising: a dissolved oxygen concentration sensor for measuring the dissolved oxygen concentration in the pure water stored in the aforementioned impregnation tank; and a control unit for controlling the supply of pure water with low dissolved oxygen concentration to the aforementioned impregnation tank so that the dissolved oxygen concentration of the pure water stored in the aforementioned impregnation tank is maintained below 100 ppb.

16. The substrate processing apparatus of claim 2, wherein the aforementioned standby unit is configured to perform the aforementioned second immersion process, wherein the aforementioned second immersion process is performed by immersing the aforementioned multiple substrates in CO2 water with a conductivity of less than 1 MΩ·cm or hydrogen water with a dissolved hydrogen concentration of greater than 1 ppm stored in the aforementioned immersion tank.

17. The substrate processing apparatus of claim 1 or 2, wherein the aforementioned conveying system further comprises: a substrate transfer unit that temporarily holds the aforementioned substrate which is removed from the aforementioned impregnation liquid by the aforementioned first substrate transfer unit; and a second substrate transfer unit that removes the aforementioned substrate from the aforementioned substrate transfer unit and transfers it to the aforementioned single-wafer processing unit; the aforementioned substrate transfer unit has: a mounting section for mounting the aforementioned substrate in a horizontal position; and a coating liquid nozzle that supplies coating liquid to the aforementioned substrate mounted on the aforementioned mounting section to maintain at least one surface of the aforementioned substrate covered by liquid.

18. The substrate processing apparatus of claim 17, wherein the first substrate conveying unit takes the substrate, which is vertically immersed in the impregnation liquid in the impregnation tank, removes it from the impregnation liquid while maintaining the vertical position, changes it to a horizontal position, and moves it into the substrate transfer unit in a horizontal position; the second substrate conveying unit takes the substrate, which is horizontally placed on the placement portion of the substrate transfer unit, and moves it into the single-wafer processing unit while maintaining the horizontal position.

19. The substrate processing apparatus according to any one of claims 3 to 6, further comprising: a circulation path connected to the aforementioned impregnation tank of the aforementioned standby unit; and a pump and a temperature regulator disposed in the aforementioned circulation path; wherein the aforementioned impregnation liquid stored in the aforementioned impregnation tank is circulated in the aforementioned circulation path and its temperature is adjusted.

20. A substrate processing method, which is performed using a substrate processing apparatus, the substrate processing apparatus comprising: a batch processing unit having a plurality of batch processing units, each of the batch processing units having a processing tank for storing processing liquid, and configured to immerse a plurality of substrates in the processing liquid stored in the processing tank to perform liquid processing on the plurality of substrates simultaneously; a single-piece processing unit having a single-piece processing unit for processing the plurality of substrates processed by the batch processing unit one by one; a standby unit having an immersion tank for storing immersion liquid, and standing by immersing the plurality of substrates processed by the batch processing unit in the immersion liquid; and a conveying system for conveying the plurality of substrates from the standby unit to the single-piece processing unit, and comprising a first substrate conveying unit for removing the plurality of substrates immersed in the immersion liquid in the immersion tank one by one from the immersion liquid. The substrate processing method involves performing at least one of a first liquid treatment and a second liquid treatment on the substrate in the aforementioned standby section. The first liquid treatment is a liquid treatment that makes the surface of the substrate hydrophilic, or a liquid treatment that increases or maintains the hydrophilicity of the surface of the substrate. The second liquid treatment is a liquid treatment that makes the zeta potential of the surface of the substrate negative.

21. A substrate processing method, which is a substrate processing method performed using a substrate processing apparatus, the substrate processing apparatus comprising: a batch processing unit having a plurality of batch processing units, each of the batch processing units having a processing tank for storing processing liquid, and configured to immerse a plurality of substrates in the processing liquid stored in the processing tank to perform liquid processing on the plurality of substrates simultaneously; a single-piece processing unit having a single-piece processing unit for processing the plurality of substrates processed by the batch processing unit one by one; a standby unit having an immersion tank for storing immersion liquid, and standing by immersing the plurality of substrates processed by the batch processing unit in the immersion liquid; and a transfer system for transferring the plurality of substrates from the standby unit to the single-piece processing unit, and comprising a first substrate transfer unit for removing the plurality of substrates immersed in the immersion liquid in the immersion tank one by one from the immersion liquid; the substrate processing method involves performing the following processing on the substrates in the standby unit: The first immersion process involves immersing the substrate in water, which is the immersion solution, and the immersion solution is controlled so that the dissolved oxygen concentration is below a predetermined value. Alternatively, the second immersion process involves immersing the substrate in hydrogen water or CO2 water, which is the immersion solution.

22. The substrate processing method of claim 20, wherein both the first liquid processing and the second liquid processing are performed in the aforementioned standby unit, wherein the first liquid processing is performed by immersing the aforementioned multiple substrates in a first processing liquid stored in the aforementioned immersion tank, the first processing liquid being a liquid capable of making the surface of the aforementioned substrates hydrophilic, or capable of increasing or maintaining the hydrophilicity of the surface of the aforementioned substrates, and wherein the second liquid processing is performed by discharging a second processing liquid capable of making the zeta potential of the surface of the aforementioned substrates negative by means of a processing liquid nozzle provided in the aforementioned standby unit when the substrates are removed from the aforementioned immersion liquid by the aforementioned first substrate conveying unit or immediately after removal.

23. The substrate processing method of claim 20, wherein the first liquid processing is performed in the aforementioned standby unit, the first liquid processing is performed by immersing the aforementioned multiple substrates in a first processing liquid stored in the aforementioned immersion tank, the first processing liquid being a liquid capable of making the surface of the aforementioned substrates hydrophilic, or capable of increasing or maintaining the hydrophilicity of the surface of the aforementioned substrates.

24. The substrate processing method of claim 20, wherein the aforementioned second liquid processing is performed in the aforementioned standby unit, the aforementioned second liquid processing is performed by immersing the aforementioned plurality of substrates in a second processing liquid stored in the aforementioned immersion tank, the aforementioned second processing liquid being a liquid capable of making the zeta potential of the aforementioned substrate surface negative.

25. The substrate processing method of claim 20, wherein the aforementioned second liquid processing is performed in the aforementioned standby unit, the aforementioned impregnation tank stores pure water as the aforementioned impregnation liquid, and the aforementioned second liquid processing is performed by supplying a second processing liquid capable of making the zeta potential of the aforementioned substrate surface negative from a processing liquid nozzle provided in the aforementioned standby unit when the substrate is removed from the aforementioned impregnation liquid by the aforementioned first substrate conveying unit or immediately after removal.

26. The substrate processing method of claim 21, wherein the first immersion process is performed in the aforementioned standby unit, and the first immersion process is performed by immersing the aforementioned multiple substrates in pure water with a dissolved oxygen concentration of less than 100 ppb stored in the aforementioned immersion tank.

27. The substrate processing method of claim 26, wherein in order to set the dissolved oxygen concentration of the pure water stored in the aforementioned impregnation tank to 100 ppb or less, at least one of the following is performed: removing dissolved oxygen from the aforementioned pure water by bubbling based on nitrogen gas, hydrogen gas or carbon dioxide gas; and supplying pure water with a low dissolved oxygen concentration, i.e., pure water with a dissolved oxygen concentration of less than 100 ppb, to the pure water stored in the aforementioned impregnation tank, such that a portion of the pure water stored in the aforementioned impregnation tank is replaced by the supplied pure water with a low dissolved oxygen concentration.

28. The substrate processing method of claim 21, wherein the aforementioned second immersion process is performed in the aforementioned standby section, wherein the aforementioned second immersion process is performed by immersing the aforementioned multiple substrates in CO2 water with a conductivity of less than 1 MΩ·cm or hydrogen water with a dissolved hydrogen concentration of greater than 1 ppm stored in the aforementioned immersion tank.

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