JP2019046869A - Substrate processing method and substrate processing apparatus - Google Patents

Abstract

To provide a substrate processing method capable of suppressing discharge or a large current between a substrate W and a processing liquid in a process after a rinse process while performing the rinse process using pure water.SOLUTION: A substrate processing method of processing a substrate having a first main surface and a second main surface opposite to the first main surface includes steps (a), (b), and (c). In the step (a), the substrate is rotated in a horizontal plane. In the step (b), the pure water is supplied to the first main surface of the substrate after the step (a). In the step (c), after the step (a), the pure water is supplied to the second main surface of the substrate at a flow rate and/or a supply period in which the charge amount of the first main surface of the substrate to be charged due to the step (b) is smaller than a first reference value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a substrate processing method and a substrate processing apparatus, and more particularly to a technology for supplying pure water to a substrate.

  Conventionally, in the process of manufacturing a semiconductor substrate (hereinafter simply referred to as "substrate"), various processes are performed on a substrate having an insulating film such as an oxide film using a substrate processing apparatus. For example, processing such as cleaning or etching is performed on the surface of the substrate by supplying the processing liquid to the surface of the substrate on which the resist pattern is formed. After the supply of the processing solution, a rinse process is performed to wash away the process solution on the surface of the substrate. However, to prevent the substrate from being charged by this rinse process, the rinse process using a rinse solution containing carbon dioxide is performed. It may be done.

  However, when a metal is exposed on the surface of the substrate W when performing the rinse process, carbon dioxide may act on the metal to corrode the metal.

  Therefore, a rinse process using pure water has been proposed as a substitute for the rinse solution containing carbon dioxide. Since pure water does not contain carbon dioxide, it does not cause metal corrosion.

  Patent Document 1 is disclosed as a technique related to the present invention.

Patent No. 3824510

  However, the resistivity of pure water is high. When such pure water is supplied to the surface of the substrate, the surface of the substrate is charged. That is, the surface of the substrate is charged in the rinse process using pure water. Then, in the next step, when a processing solution having a small specific resistance, such as SPM for removing a resist, is supplied to the surface of the charged substrate, the substrate and the processing solution are just before the processing solution is deposited on the surface of the substrate. Discharge may occur between the substrate and the processing liquid (or a large current may be generated) after the processing liquid is deposited on the surface of the substrate. Such discharge or large current may cause damage to the pattern on the surface of the substrate.

  Therefore, the present invention provides a substrate processing method and a substrate processing apparatus capable of suppressing a discharge or a large current between the substrate W and the processing liquid in a process after the rinse process while performing a rinse process using pure water. The purpose is to

  In order to solve the above-mentioned subject, the 1st mode of the substrate processing method concerning the present invention processes to the substrate which has the 1st principal surface and the 2nd principal surface on the opposite side to the 1st principal surface. A method of processing a substrate, comprising: (a) rotating the substrate in a horizontal plane; and (b) supplying pure water to the first major surface of the substrate after the step (a); After the step (a), the flow rate and / or the supply period of the charge amount of the first main surface of the substrate charged due to the step (b) are smaller than the first reference value. And (c) supplying pure water to the second main surface.

  A second aspect of the substrate processing method according to the present invention is the substrate processing method according to the first aspect, wherein at least a part of the execution period of the step (b) and at least the execution period of the step (c) Some overlap.

  A third aspect of the substrate processing method according to the present invention is the substrate processing method according to the first or second aspect, wherein the step (c) measures the surface potential of the first main surface of the substrate. Step (c1), and step (c2) of determining whether the supply of pure water to the second main surface of the substrate is ended based on the surface potential measured in the step (c1) including.

  A fourth aspect of the substrate processing method according to the present invention is the substrate processing method according to any one of the first to third aspects, wherein the step (b) is performed on the first main surface of the substrate. A step (b1) of depositing pure water in a first central portion, a first surface potential in the first central portion, and a first peripheral portion on a peripheral side of the first central portion of the first main surface And (b2) applying pure water to the first peripheral portion at a flow rate and / or a supply period at which the difference with the second surface potential is smaller than a second reference value.

  A fifth aspect of the substrate processing method according to the present invention is the substrate processing method according to the fourth aspect, wherein in the step (b), the step (b) is performed in the first central portion of the first main surface of the substrate. (1) The method further comprises the step (b3) of measuring the surface potential and the second surface potential at the first peripheral portion, and in the step (b2), whether or not the supply of pure water to the first peripheral portion is ended. Is determined based on the difference between the first surface potential and the second surface potential measured in the step (b3).

  A sixth aspect of the substrate processing method according to the present invention is the substrate processing method according to the fifth aspect, wherein in the step (b3), a surface voltmeter and the first central portion of the first main surface are used. A step of measuring the first surface potential by the surface electrometer in a state of being moved to an opposing position, and moving the surface electrometer to a position opposed to the first peripheral portion of the first main surface And, in the state, measuring the second surface potential by the surface potentiometer.

  A seventh aspect of the substrate processing method according to the present invention is the substrate processing method according to the fifth aspect, wherein the step (b3) comprises the step of measuring the first surface potential by the first surface voltmeter And a second surface voltmeter different from the first surface voltmeter measuring the second surface potential.

  An eighth aspect of the substrate processing method according to the present invention is the substrate processing method according to any one of the fourth to seventh aspects, wherein the step (c) is performed on the second main surface of the substrate. In the step (c1) of depositing pure water in the second central portion, the flow rate and / or the supply period for reducing the difference between the first surface potential and the second surface potential, the second main surface And 2) a step (c2) of depositing pure water on a second peripheral edge portion on the peripheral edge side of the central portion.

  A ninth aspect of the substrate processing method according to the present invention is the substrate processing method according to the eighth aspect, wherein in the step (c1), the nozzle is a second central portion of the second main surface of the substrate. And the nozzle discharges pure water toward the second central portion in a state of being moved to a position facing the second substrate, and in the step (c2), the nozzle is moved to the second main surface of the second main surface of the substrate. The nozzle discharges pure water toward the second peripheral portion while being moved to a position facing the peripheral portion.

  A tenth aspect of the substrate processing method according to the present invention is the substrate processing method according to the eighth aspect, wherein in the step (c1), the first nozzle is the second of the second main surface of the substrate. The pure water is discharged toward the central portion, and in the step (c2), the second nozzle different from the first nozzle discharges the pure water toward the second peripheral portion of the second main surface.

  An eleventh aspect of the substrate processing method according to the present invention is the substrate processing method according to any one of the first to tenth aspects, wherein both the step (b) and the step (c) are performed. Then, the method further includes the step (d) of supplying a processing liquid having a smaller specific resistance than pure water to the first main surface of the substrate.

  A twelfth aspect of the substrate processing method according to the present invention is the substrate processing method according to any one of the first to eleventh aspects, wherein an insulating film and a metal film are provided on the first main surface of the substrate. It is formed.

  A thirteenth aspect of the substrate processing method according to the present invention is the substrate processing method according to any one of the first to twelfth aspects, wherein the specific resistance of the pure water is 10 [MΩ · cm] or more. .

  A fourteenth aspect of the substrate processing method according to the present invention is directed to a substrate having a first main surface on which an insulating film and a metal film are formed, and a second main surface opposite to the first main surface. A method for processing a substrate, comprising: (a) rotating the substrate in a horizontal plane; and (b) supplying pure water to the first major surface of the substrate after the step (a). And after the step (a), the step (c) of supplying pure water to the second main surface of the substrate, and after both the steps (b) and (c) have been performed, And (d) supplying a processing liquid having a smaller specific resistance than pure water to the first main surface of the substrate.

  A fifteenth aspect of the substrate processing apparatus according to the present invention is a substrate holding means for holding a substrate having a first main surface and a second main surface opposite to the first main surface, and the substrate holding means. Rotation mechanism for rotating the substrate, first pure water supply means for supplying pure water to the first main surface of the substrate, and second pure water supply means for supplying pure water to the second main surface of the substrate; The second pure water supply means at a flow rate and / or a supply period in which the charge amount of the first main surface to be charged due to the supply of pure water to the first main surface is reduced than a first reference value And control means for supplying pure water to the second main surface.

  A sixteenth aspect of the substrate processing apparatus according to the present invention is the substrate processing apparatus according to the fifteenth aspect, wherein the substrate holding means is grounded.

  According to the first aspect of the substrate processing method of the present invention and the fifteenth and sixteenth aspects of the substrate processing apparatus, since the charge amount of the first main surface can be made smaller than the reference value, the first main surface of the substrate Discharge or large current between the substrate and the processing liquid when the processing liquid is supplied to the

  According to the second aspect of the substrate processing method of the present invention, the processing throughput can be improved.

  According to the third aspect of the substrate processing method of the present invention, the surface potential of the first main surface of the substrate can be controlled with high accuracy.

  According to the fourth aspect of the substrate processing method of the present invention, the surface potential of the first main surface of the substrate can be made uniform.

  According to the fifth and sixth aspects of the substrate processing method of the present invention, the surface potential of the first main surface of the substrate can be made uniform more accurately.

  According to the seventh aspect of the substrate processing method of the present invention, the first surface potential and the second surface potential can be measured at the same time.

  According to the eighth to tenth aspects of the substrate processing method of the present invention, the distribution of the surface potential of the first main surface of the substrate can be controlled.

It is a figure showing roughly an example of the composition of a substrate processing device. It is a flowchart which shows an example of operation | movement of a substrate processing apparatus. It is a figure which shows typically an example of the electric state of a board | substrate. It is a graph which shows an example of the relationship between the surface potential of a board | substrate, and the position of the radial direction of a board | substrate. It is a figure which shows typically an example of the electric state of a board | substrate. It is a graph which shows an example of the relationship between the surface potential of a board | substrate, and the position of the radial direction of a board | substrate. It is a graph which shows an example of the relationship between the surface electric potential of a board | substrate, and the flow volume of the pure water to the back surface of a board | substrate. It is a flowchart which shows an example of operation | movement of a substrate processing apparatus. It is a flowchart which shows an example of the operation | movement in the rinse process of a substrate processing apparatus. It is a figure showing roughly an example of composition of a surface side pure water supply part. It is a figure showing roughly an example of the composition of a substrate processing device. It is a flow chart which shows an example of operation in electric charge control processing of a substrate processing device. It is a flowchart which shows an example of the operation | movement in the rinse process of a substrate processing apparatus. It is a figure which shows roughly an example of a structure of a surface side pure water supply part and a surface electric potential measurement part. It is a figure showing roughly an example of the composition of a substrate processing device. It is a flow chart which shows an example of operation in electric charge control processing of a substrate processing device. It is a figure which shows roughly an example of a structure of a back surface side pure water supply part. It is a figure showing roughly an example of the composition of a substrate processing device.

  Hereinafter, embodiments will be described in detail with reference to the drawings. Further, for the purpose of easy understanding, the dimensions and the number of each part are drawn in an exaggerated or simplified manner as necessary.

<Substrate processing apparatus>
FIG. 1 is a view schematically showing an example of the configuration of a substrate processing apparatus 1. The substrate processing apparatus 1 is an apparatus for processing a substrate W. The substrate W is, for example, a semiconductor substrate, and is a plate-like substrate having a circular shape in plan view. However, the substrate W is not limited to this, and may be, for example, a substrate for a display panel such as liquid crystal, and may be a plate-like substrate having a rectangular shape in plan view.

  In the example of FIG. 1, the substrate processing apparatus 1 includes a substrate holding unit 10, a front side pure water supply unit 20, a back side pure water supply unit 30, a chemical solution supply unit 40, a control unit 50, and a housing 70. .

  The housing 70 forms a processing chamber for processing the substrate W. The housing 70 may also be referred to as a chamber. The housing 70 is formed with a loading / unloading port (not shown) for loading / unloading the substrate W. In addition, the housing 70 is provided with a shutter (not shown) for switching the opening and closing of the loading / unloading port.

  A substrate transfer unit (not shown) is provided outside the substrate processing apparatus 1, and the substrate transfer unit transfers the substrate W with the substrate processing apparatus 1. Specifically, the substrate transfer means carries the substrate W from the outside of the housing 70 to the inside through the loading / unloading opening with the shutter open, or carries out the substrate W from the inside of the housing 70 to the outside. To

  The substrate holding unit 10 is provided inside the housing 70 and holds the substrate W horizontally. The substrate W has a pair of main surfaces facing each other in the thickness direction, and in the following, the main surface located on the upper side in the state of being held by the substrate holding unit 10 is called the surface, and the opposite side to this surface The main surface of is called the back surface.

  Although the configuration of the substrate holding unit 10 is not particularly limited, in the example of FIG. 1, the base 11 and the plurality of pins 12 are provided. The base 11 has a plate-like shape, and the thickness direction of the base 11 is disposed along the vertical direction. The base 11 has, for example, a circular shape in plan view.

  The plurality of pins 12 project upward from the top surface of the base 11. The plurality of pins 12 are spaced along the periphery of the substrate W in plan view, and hold the periphery of the substrate W. Thus, in the state where the substrate W is held, the base 11 faces the back surface of the substrate W in the vertical direction.

  In the substrate holding unit 10, the base 11 and the pin 12 can also be referred to as a chuck base and a chuck pin, respectively.

  The base 11 is formed with a hole 111 which is penetrated by a part of the back surface side pure water supply unit 30 described later. The hole 111 is formed at a position opposed to the center of the substrate W in the vertical direction, and penetrates the base 11 along the vertical direction.

  The substrate holding unit 10 (base 11 and pin 12) has conductivity and is electrically grounded. For example, the substrate holding unit 10 is formed of a conductive ceramic or conductive resin.

  Inside the housing 70, a rotation mechanism 13 for rotating the substrate holding unit 10 is provided. The rotation mechanism 13 rotates the substrate holding unit 10 with an axis extending in the vertical direction through the center of the substrate W as a rotation axis. Thereby, the substrate W held by the substrate holding unit 10 rotates in the horizontal plane about the rotation axis. The structure consisting of the substrate holding unit 10 and the rotation mechanism 13 can also be called a spin chuck.

  The rotation mechanism 13 has, for example, a hollow motor, and is provided below the substrate holding unit 10 inside the housing 70. The hollow motor has a hollow portion extending in the vertical direction. A part of the below-mentioned back surface side pure water supply unit 30 penetrates the hollow portion of this hollow motor.

  The chemical solution supply unit 40 supplies the chemical solution to the surface of the substrate W held by the substrate holding unit 10. Thereby, processing based on the chemical solution can be performed on the surface of the substrate W. Although various chemical solutions can be employed as this chemical solution, in the example of FIG. 1, a mixed solution of sulfuric acid and hydrogen peroxide solution (SPM: Sulfuric Acid-Hydrogen Peroxide Mixture) is employed as the chemical solution. This mixture can remove the resist on the surface of the substrate W. In other words, before the substrate W is carried into the substrate processing apparatus 1, a resist is formed on the surface of the substrate W. The substrate W is carried into the inside of the substrate processing apparatus 1 and the mixed solution is supplied from the chemical solution supply unit 40 to the surface of the substrate W, whereby the mixed solution reacts with the resist on the surface of the substrate W The resist is removed from the surface of the substrate W. On the surface of the substrate W from which the resist has been removed, for example, the insulating film and the metal film (for example, a wiring pattern) are exposed.

  In the example of FIG. 1, the chemical solution supply unit 40 includes a nozzle 41, a sulfuric acid supply unit 42, a hydrogen peroxide solution supply unit 43, a mixed liquid generation unit 44, and a nozzle moving mechanism 45.

  The sulfuric acid supply unit 42 supplies sulfuric acid to the liquid mixture generation unit 44. In the example of FIG. 1, the sulfuric acid supply unit 42 includes a pipe 421 and an on-off valve 422. One end of the pipe 421 is connected to the sulfuric acid supply source 423, and the other end is connected to the mixed liquid generation unit 44. The on-off valve 422 is provided in the middle of the pipe 421. By opening the on-off valve 422, the sulfuric acid from the sulfuric acid supply source 423 flows through the inside of the pipe 421 and is supplied to the liquid mixture generator 44, and the on-off valve 422 is closed to stop the supply of sulfuric acid. The pipe 421 may be provided with heating means (not shown) for heating sulfuric acid. By heating the sulfuric acid, the reactivity of the mixture can be enhanced, and the resist can be effectively removed.

  The hydrogen peroxide solution supply unit 43 supplies the mixed solution generation unit 44 with the hydrogen peroxide solution. In the example of FIG. 1, the hydrogen peroxide solution supply unit 43 includes a pipe 431 and an on-off valve 432. One end of the pipe 431 is connected to the hydrogen peroxide solution supply source 433, and the other end is connected to the mixed liquid generation unit 44. The on-off valve 432 is provided in the middle of the pipe 431. By opening the on-off valve 432, the hydrogen peroxide solution from the hydrogen peroxide solution supply source 433 flows through the inside of the pipe 431 and is supplied to the mixed liquid generation unit 44, and the on-off valve 432 is closed. Water supply is stopped.

  The mixed liquid generation unit 44 mixes the sulfuric acid and the hydrogen peroxide solution, and supplies the mixed liquid to the nozzle 41. In the example of FIG. 1, the mixed liquid generation unit 44 includes a mixing unit (for example, a mixing valve) 441 and a pipe 442. The other ends of the pipes 421 and 431 are connected to the mixing unit 441, and sulfuric acid and hydrogen peroxide water are supplied from each other. One end of the pipe 442 is connected to the mixing unit 441, and the other end is connected to the nozzle 41. The mixed liquid mixed in the mixing section 441 flows through the inside of the pipe 442 and is supplied to the nozzle 41.

  The nozzle 41 is disposed inside the housing 70 in a posture in which the discharge port 41 a is directed downward. The nozzle 41 discharges the mixed liquid supplied from the pipe 442 as a chemical solution from the discharge port 41a.

  The nozzle moving mechanism 45 reciprocates the nozzle 41 between a processing position (hereinafter referred to as a chemical processing position) and a standby position (hereinafter referred to as a chemical liquid standby position). The chemical treatment position is the position of the nozzle 41 when the chemical solution (SPM in the above example) is supplied from the nozzle 41 to the surface of the substrate W, and is the upper position of the substrate W held by the substrate holder 10 . More specifically, the chemical processing position is a position facing the center of the surface of the substrate W in the vertical direction. By opening the on-off valves 422 and 432 in a state where the nozzle 41 is stopped at the chemical processing position, the chemical is discharged from the discharge port 41 a of the nozzle 41 toward the surface of the substrate W and attached to the center of the surface of the substrate W Liquid.

  The chemical solution standby position is, for example, a position not facing the substrate W held by the substrate holding unit 10 in the vertical direction. When the nozzle 41 is stopped at the chemical solution standby position, the nozzle 41 is not located above the substrate W, so the delivery of the substrate W between the external substrate transfer unit and the substrate holding unit 10 is not hindered.

  Although the configuration of the nozzle moving mechanism 45 is not particularly limited, for example, a pillar member located on the side of the substrate holder 10 and extending in the vertical direction, and horizontally extending from the pillar member and the pillar member and the nozzle 41 A connecting member to be connected and a pivoting mechanism are provided. The pivoting mechanism pivots the pillar member around a central axis of the pillar member. By this rotation, the nozzle 41 moves along an arc centered on the rotation axis. The drug solution processing position and the drug solution standby position are located on the arc.

  The surface side pure water supply unit 20 supplies pure water to the surface of the substrate W. Thereby, the surface of the substrate W can be washed away. Specifically, the chemical solution supplied from the chemical solution supply unit 40 can be washed away from the surface of the substrate W. As pure water, for example, pure water having a specific resistance of 10 [MΩ · cm] or more (for example, 18.2 [MΩ · cm]) can be adopted.

  The surface side pure water supply unit 20 includes a nozzle 21, a pipe 22, an open / close valve 23, and a nozzle moving mechanism 24. The nozzle 21 is disposed inside the housing 70 in a posture in which the discharge port 21 a is directed downward. One end of the pipe 22 is connected to the nozzle 21, and the other end is connected to the pure water supply source 25. The on-off valve 23 is provided in the middle of the pipe 22. By opening the on-off valve 23, pure water from the pure water supply source 25 flows through the inside of the pipe 22 and is discharged from the discharge port 21 a of the nozzle 21. Further, when the on-off valve 23 is closed, the discharge of the pure water from the discharge port 21 a of the nozzle 21 is stopped.

  The nozzle moving mechanism 24 reciprocates the nozzle 21 between a processing position (hereinafter referred to as a pure water processing position) and a standby position (hereinafter referred to as a pure water standby position). The pure water processing position is the position of the nozzle 21 when pure water is supplied from the nozzle 21 to the surface of the substrate W, and is, for example, the upper position of the substrate W held by the substrate holding unit 10. More specifically, the pure water processing position is a position facing the center of the substrate W in the vertical direction. By opening the on-off valve 23 in a state where the nozzle 21 is stopped at the pure water processing position, pure water is discharged from the discharge port 21 a of the nozzle 21 toward the surface of the substrate W, and liquid deposition on the center of the surface of the substrate W Do.

  The pure water standby position is, for example, a position not facing the substrate W held by the substrate holder 10 in the vertical direction. When the nozzle 21 is stopped at the pure water standby position, the nozzle 21 is not located above the substrate W, so the delivery of the substrate W between the external substrate transfer unit and the substrate holding unit 10 is not inhibited. An example of a specific configuration of the nozzle moving mechanism 24 is the same as the nozzle moving mechanism 45, so repeated description will be avoided.

  When the surface-side pure water supply unit 20 supplies pure water having a high specific resistance to the surface of the substrate W, charges are accumulated on the surface of the substrate W and are charged. This is because charge is accumulated on the surface of the substrate W by physical contact such as collision and friction between pure water and the substrate W.

  The back surface side pure water supply unit 30 supplies pure water to the back surface of the substrate W in order to control the charge amount of the substrate W. More specifically, the back surface side pure water supply unit 30 supplies pure water to the back surface of the substrate W under supply conditions (flow rate and / or supply period) for reducing the charge amount on the front surface of the substrate W than the charging reference value. Supply. In other words, under the supply conditions for reducing the absolute value (that is, the charge amount) of the electric potential of the surface of the substrate W (hereinafter referred to as surface electric potential) below the electric potential reference value, the back surface side pure water supply unit 30 Supply pure water to the back side. The relationship between the supply of pure water to the back surface of the substrate W and the surface potential will be described in detail later.

  In the example of FIG. 1, the back surface side pure water supply unit 30 includes a nozzle 31, a pipe 32 and an on-off valve 33. The nozzle 31 is disposed in a posture in which the discharge port 31a is directed upward. One end of the pipe 32 is connected to the nozzle 31, and the other end is connected to the pure water supply source 25. One set of the nozzle 31 and the pipe 32 penetrates the rotation mechanism 13 (for example, a hollow portion of a hollow motor) and the hole 111 of the substrate holding unit 10 along the vertical direction. Therefore, the nozzle 31 is disposed so that the discharge port 31 a thereof faces the back surface side of the substrate W on the lower side of the substrate W. In the example of FIG. 1, the nozzle 31 is disposed at a position facing the center of the back surface of the substrate W in the vertical direction.

  The on-off valve 33 is provided in the middle of the pipe 32. When the on-off valve 33 is opened, the pure water from the pure water supply source 25 flows through the inside of the piping 32 and is discharged toward the back surface of the substrate W from the discharge port 31 a of the nozzle 31. Apply liquid. Further, when the on-off valve 33 is closed, the discharge of the pure water from the discharge port 31 a of the nozzle 31 is stopped.

  In the example of FIG. 1, the substrate processing apparatus 1 is provided with a cup 60. The cup 60 has a substantially cylindrical (for example, cylindrical) shape, and is provided inside the housing 70 so as to surround the substrate holding unit 10. The cup 60 has a side portion 61 extending along the vertical direction, and a collar portion 62 which inclines inward as it goes upward from the upper end of the side portion. The processing liquid (including a chemical solution and pure water) scattered from the peripheral edge of the substrate W collides with the inner peripheral surface of the cup 60 and falls by gravity. A recovery port 71 for recovering the processing liquid is formed on the lower surface of the casing 70 inside the cup 60, and the processing liquid flows to the outside through the recovery port 71.

  The control unit 50 controls the entire substrate processing apparatus 1. Specifically, the control unit 50 controls the rotation mechanism 13, the on-off valves 23, 33, 422, and 432, and the nozzle moving mechanism 24 and 45. Further, the control unit 50 can control the shutter provided in the housing 70.

  The control unit 50 is an electronic circuit device, and may have, for example, a data processing device and a storage medium. The data processing device may be, for example, an arithmetic processing device such as a CPU (Central Processor Unit). The storage unit may have a non-transitory storage medium (for example, a ROM (Read Only Memory) or a hard disk) and a temporary storage medium (for example, a RAM (Random Access Memory)). The non-temporary storage medium may store, for example, a program that defines a process performed by the control unit 50. The processing unit executes this program, whereby the control unit 50 can execute the processing defined in the program. Of course, part or all of the process performed by the control unit 50 may be performed by hardware.

<Substrate processing method>
FIG. 2 is a flowchart showing an example of the operation of the substrate processing apparatus 1. In the initial state, the nozzles 21 and 41 stop at the pure water standby position and the chemical liquid standby position, respectively, and the open / close valves 23, 33, 422, and 432 are closed. First, at step S1, the substrate W is carried in. Specifically, after the control unit 50 opens the shutter, the external substrate transfer unit transfers the substrate W into the inside of the housing 70 via the loading / unloading port, and arranges the substrate W in the substrate holding unit 10. Thereby, the substrate holding unit 10 holds the substrate W.

  Next, in step S2, the control unit 50 executes a chemical solution process. Specifically, the control unit 50 controls the nozzle moving mechanism 45 to move the nozzle 41 to the chemical processing position. Further, the control unit 50 controls the rotation mechanism 13 to rotate the substrate holding unit 10. Thereby, the substrate W rotates in the horizontal plane. In this state, the control unit 50 opens the on-off valves 422 and 432 to supply the chemical solution (SPM) from the nozzle 41 to the surface of the substrate W. The chemical solution is deposited on the center of the surface of the substrate W, receives centrifugal force, spreads on the surface of the substrate W, and is scattered from the peripheral edge of the substrate W. Since the chemical solution spreads over the entire surface of the substrate W, processing based on the chemical solution is performed on the entire surface of the substrate W. More specifically, the resist formed on the surface of the substrate W is removed by the chemical solution.

  For example, when the elapsed time from the time when the on-off valves 422 and 432 are opened exceeds the first predetermined time, the control unit 50 ends the chemical liquid process. Specifically, the control unit 50 closes the on-off valves 422 and 432 to end the supply of the chemical solution, and controls the nozzle moving mechanism 45 to move the nozzle 41 to the chemical solution standby position. The first predetermined time is set to a time suitable for removing the resist.

  Next, in step S3, the control unit 50 executes a rinse process. Specifically, the control unit 50 controls the nozzle moving mechanism 24 to move the nozzle 21 to the pure water treatment position. Further, the control unit 50 controls the rotational speeds of the substrate holding unit 10 and the substrate W within a range suitable for the rinse process. The rotation speed in the rinse process may be different from or the same as the rotation speed in the chemical solution process. In this state, the control unit 50 opens the on-off valve 23 to supply pure water from the nozzle 21 to the surface of the substrate W. The pure water is deposited on the center of the surface of the substrate W, receives centrifugal force, and spreads on the surface of the substrate W, thereby washing the chemical solution from the surface of the substrate W to the outer peripheral side. In other words, the chemical solution on the surface of the substrate W is replaced with pure water.

  The control unit 50 ends the rinsing process, for example, when the elapsed time from the time when the on-off valve 23 is opened exceeds the second predetermined time. Specifically, the control unit 50 closes the on-off valve 23 to end the supply of pure water, and controls the nozzle moving mechanism 24 to move the nozzle 21 to the pure water standby position. The second predetermined time is set to a time suitable for the rinse process.

  By the rinse process, the surface of the substrate W is negatively charged. This is because a negative charge is charged on the surface of the substrate W due to collision, friction, etc. between pure water having a high resistivity and the substrate W. In addition, it is thought that the ionegativity which exists in a pure water adsorb | sucks to the board | substrate W, and the electronegativity of the surface of the board | substrate W increasing is also a factor which increases a charge amount.

  FIG. 3 is a cross-sectional view schematically showing an example of an electrical state (charged state) of the substrate W after supplying pure water to the surface of the substrate W. As shown in FIG. In the example of FIG. 3, the fact that the surface of the substrate W is negatively charged is schematically shown by a symbol of negative charge and a circle surrounding it.

  Here, in order to simplify the description, it is assumed that insulating films (for example, silicon oxide films) 1a and 1b are formed on the front surface and the back surface of the substrate W, respectively. In the following, the layer sandwiched between the insulating films 1a and 1b in the substrate W is also referred to as an inner layer (for example, a silicon layer) 1c. At least the inner layer 1c is in contact with the substrate holder 10 (more specifically, the pin 12).

  FIG. 4 is a graph showing an example of the relationship between the surface potential of the substrate W and the position on the surface of the substrate W at this time. Here, the surface potential of the substrate W with respect to the ground potential is employed as the surface potential of the substrate W. In FIG. 4, the position in the radial direction of the substrate W is adopted on the horizontal axis, and the surface potential of the substrate W is adopted on the vertical axis. Hereinafter, the radial direction of the substrate W will be simply referred to as the radial direction. Since pure water is deposited on the center of the surface of the substrate W and isotropically spreads over the surface of the substrate W, the surface potential has a shape that is substantially symmetrical with respect to the center of the substrate W. In FIG. 4, the surface potential has a downward convex shape (more specifically, a substantially dish shape), takes a negative value in a relatively wide range near the center of the substrate W, and near the periphery of the substrate W In a relatively narrow range, the width increases as the periphery of the substrate W is approached. As illustrated in FIG. 4, although the surface W of the substrate W has a positive value in the vicinity of the peripheral edge, its absolute value is not so large, and the entire surface of the substrate W is negatively charged. .

  Referring back to FIG. 3, when the surface of the substrate W is negatively charged, the positive charge is transferred to the inner layer of the substrate W via the grounded substrate holder 10 in an attempt to maintain the electrical neutrality of the substrate W. It is injected into 1c. In other words, the negative charge of the inner layer 1 c flows out to the substrate holding unit 10. As a result, the internal layer 1c of the substrate W becomes electrically positive. In the example of FIG. 3, the fact that the inside of the inner layer 1 c is electrically positive is indicated by a symbol of positive charge and a circle surrounding it.

  When the inner layer 1c becomes electrically positive in this manner, induced polarization occurs in the insulating film 1b. Specifically, in the portion on the inner layer 1c side of the insulating film 1b, the positive charge of the inner layer 1c is attracted and a negative charge appears, while the portion on the back side of the insulating film 1b is positive A charge appears. In the example of FIG. 3, this induced polarization is schematically shown by symbols of positive and negative charges and a frame surrounding them.

  As described above, when the surface of the substrate W is negatively charged, the influence appears on the back surface side of the substrate W. Conversely, it can be understood that the charge state of the surface of the substrate W can be influenced by changing the charge state of the back surface of the substrate W.

  Therefore, in step S4, the control unit 50 executes the charge control process. Specifically, the control unit 50 opens the on-off valve 33 and supplies pure water from the nozzle 31 to the back surface of the substrate W. Pure water is deposited on the center of the back surface of the substrate W. Also in this charge control process, the control unit 50 controls the rotation mechanism 13 to rotate the substrate W, so that pure water receives centrifugal force and spreads over the entire back surface of the substrate W, from the periphery of the substrate W It is scattered outside. The rotational speed of the substrate W in the charge control process may be different from or the same as the rotational speed in the rinse process.

  When the pure water flows on the back surface of the substrate W, the back surface of the substrate W is also negatively charged. FIG. 5 is a cross-sectional view schematically showing an example of the electrical state of the substrate W after pure water is supplied to both the front surface and the back surface of the substrate W. FIG. 6 shows the substrate W at this time. Is a graph showing an example of the relationship between the surface potential of the substrate W and the position on the surface of the substrate W.

  As the back surface of the substrate W is negatively charged, the surface potential of the substrate W is increased as shown in FIG. This is considered to be because the charge state of the insulating films 1a and 1b and the inner layer 1c changes due to the charging of the back surface of the substrate W, and the amount of charge on the surface of the substrate W decreases under the influence of the change. Such knowledge has not been known so far, and has been discovered by the present inventors. As can be seen from the comparison of FIG. 4 and FIG. 6, the surface potential of the substrate W is increased by approximately a constant amount, regardless of the position in the radial direction. That is, since the surface potential also increases in the vicinity of the peripheral edge of the substrate W, the absolute value of the surface potential in the vicinity of the peripheral edge is larger than the value before the supply of pure water to the back surface. However, since the range near the peripheral edge where the surface potential increases is narrow with respect to the diameter of the substrate W, the absolute value of the surface potential is reduced as a whole. In other words, the integral value of the absolute value of the surface potential with respect to the area of the substrate W is reduced.

  The control unit 50 ends the charge control process, for example, when the elapsed time from the time when the on-off valve 33 is opened exceeds the third predetermined time. Specifically, the control unit 50 closes the on-off valve 33 to stop the supply of pure water to the back surface of the substrate W. The third predetermined time is set to a time suitable to bring the surface potential of the substrate W into a predetermined range. This point will be described later.

  Next, in step S5, the control unit 50 performs a drying process. For example, the control unit 50 controls the rotation mechanism 13 to increase the rotation speed of the substrate W, thereby scattering pure water on the front surface and the back surface of the substrate W from its peripheral edge to dry the substrate W. The control unit 50 ends the drying process, for example, when the elapsed time from the time when the rotational speed is increased exceeds the fourth predetermined time. Specifically, the control unit 50 controls the rotation mechanism 13 to stop the rotation of the substrate W. The fourth predetermined time is set to a time suitable for the drying process.

  Next, in step S6, the substrate W is unloaded. Specifically, after the control unit 50 opens the shutter, the external substrate transfer means takes out the substrate W from the substrate holding unit 10 via the loading / unloading port and carries it out of the casing 70.

  As described above, according to the substrate processing apparatus 1, the surface potential of the substrate W reduced in the negative region due to the supply of pure water to the surface of the substrate W (step S3) is reduced to the back surface of the substrate W. It can be brought close to zero by the supply of pure water (step S4). Therefore, even if a processing liquid having a smaller specific resistance than pure water is supplied to the surface of the substrate W in a later step of the substrate processing apparatus 1, a discharge or a large current is generated between the substrate W and the processing liquid. It can be suppressed or avoided.

<Flow rate of pure water supplied to the back surface of the substrate W>
FIG. 7 is a graph showing an example of the relationship between the flow rate of pure water supplied to the back surface of the substrate W and the surface potential of the substrate W. FIG. 7 shows the result when pure water is supplied to the back surface of the substrate W on which the surface is charged by supplying pure water of 2000 [ml / min] to the front surface. In FIG. 7, when the flow rate of pure water supplied to the back surface of the substrate W is 0, 500, 1000, and 1500 [ml / min], the surface potential at a certain position on the surface of the substrate W is shown as a discrete value. ing. The supply period of pure water to the back surface of the substrate W is the same. Further, FIG. 7 also shows an approximation line based on the discrete values of the surface potential.

  As shown in FIG. 7, the surface potential of the substrate W increases as the flow rate of pure water to the back surface of the substrate W increases. In other words, the surface potential of the substrate W has a positive correlation with the flow rate of pure water to the back surface of the substrate W.

  Even if the flow rate of pure water to the back surface of the substrate W is the same, the surface potential of the substrate W is different if the supply period is different. Specifically, the surface potential of the substrate W increases with the passage of time immediately after the start of pure water supply to the back surface of the substrate W, and eventually approaches a predetermined value according to the flow rate. The predetermined value increases as the flow rate increases.

  Based on the above-described relationship, it is possible to determine in advance the pure water supply conditions such that the absolute value of the surface potential of the substrate W becomes smaller than the potential reference value. In other words, it is possible to determine in advance the pure water supply conditions such that the charge amount of the substrate W becomes smaller than the reference value.

  By the way, in FIG. 7, when the flow rate of pure water supplied to the back surface of the substrate W is 0 [ml / min], the surface potential has a negative value. That is, the surface potential has a negative value when a flow rate of 2000 [ml / min] is supplied to the surface of the substrate W. On the other hand, when pure water is supplied to the back surface of the substrate W at a flow rate of 500 [ml / min], the surface potential increases to a positive value. That is, it is understood that the flow rate of pure water to be supplied to the back surface of the substrate W may be smaller than the flow rate of pure water supplied to the surface of the substrate W in order to bring the absolute value of the surface potential of the substrate W closer to zero. . Therefore, the control unit 50 may supply the pure water to the back surface of the substrate W at a flow rate smaller than that of pure water supplied to the front surface of the substrate W.

  As described above, it is possible to determine the flow rate and supply period (third predetermined period) of pure water which makes the absolute value of the surface potential smaller than the potential reference value. The control unit 50 ends the supply of pure water to the back surface when the elapsed time from the time when the on-off valve 33 is opened exceeds the third predetermined time.

  As can be understood from the comparison of FIGS. 4 and 6, it is not necessary to reduce the absolute value of the surface potential at all the positions of the substrate W, as long as the absolute value of the surface potential as a whole is reduced. In other words, the control unit 50 causes the back surface side pure water supply unit 30 to supply the substrate under the supply condition (flow rate and supply period) in which the integral value of the absolute value of the surface potential of the surface of the substrate W becomes smaller than the potential reference value. Pure water may be supplied to the back surface of W.

<Effect of substrate processing apparatus>
According to the substrate processing apparatus 1, the surface potential of the substrate W is controlled by the supply of pure water to the back surface of the substrate W. Therefore, it is not necessary to consider the surface potential of the substrate W in the rinse process. Therefore, in the rinse process, the flow rate of pure water or the like can be determined without considering the surface potential. Thus, setting conditions such as the flow rate of pure water can be determined so that the chemical solution can be properly washed away. As a result, the rinse treatment can be more appropriately performed to wash out the chemical solution appropriately.

  Also, unlike the prior art, it is not necessary to employ water containing carbon dioxide in the rinse process. When metal (including a wiring pattern) is exposed on the surface of the substrate W, the carbon dioxide corrodes the metal of the substrate W. In the substrate processing apparatus 1, the metal is on the surface of the substrate W as such. Even if exposed, it does not cause metal corrosion. For example, this metal is used as a wiring material for BEOL (Back End of Line), such as copper, aluminum or tungsten.

  Further, as in the prior art, it is not necessary to irradiate the surface of the substrate W with ultraviolet light to remove electricity from the surface of the substrate W. When the ultraviolet rays are applied not only to the surface of the substrate W but also to each component in the processing chamber, each component is unnecessarily charged by the photoelectric effect, or the ultraviolet rays react with the air in the processing chamber to ionize ions. In some cases, the ions may act on the surface of the substrate W and the surfaces of various components to degrade the surface. The substrate processing apparatus 1 does not cause such charging or deterioration.

<Pre-rinse treatment>
In the example described above, the rinse process (step S3) is performed after the chemical solution process (step S2). However, the rinse process (so-called pre-rinse process) may be performed before the chemical solution process. Referring to FIG. 2, the substrate processing apparatus 1 may perform a pre-rinsing process between steps S1 and S2. That is, the surface of the substrate W may be cleaned by washing the surface of the substrate W with pure water before performing the chemical treatment. Thus, the chemical solution can be supplied to the surface of the clean substrate W in the chemical solution processing.

  However, since the surface of the substrate W can be negatively charged by this pre-rinsing process, it is preferable to perform the charge control process before the chemical liquid process, corresponding to the pre-rinsing process. As described with reference to FIG. 2, it is desirable that the substrate processing apparatus 1 perform both the pre-rinsing process and the charge control process between steps S1 and S2. Thereby, while cleaning the surface of the substrate W, generation of a discharge or a large current between the chemical solution and the substrate W in the chemical solution processing of step S2 can be suppressed or avoided.

<Multiple chemical treatment>
The substrate processing apparatus 1 may be capable of supplying a chemical solution different from the chemical solution supplied by the chemical solution supply unit 40 to the surface of the substrate W. For example, a chemical solution supply unit may be provided to supply a first chemical solution for wet etching to the substrate W on which a resist pattern is formed.

  The substrate processing apparatus 1 performs a first chemical solution process for supplying a first chemical solution (for example, a chemical solution for wet etching) to the surface of the substrate W and a first rinse process for washing out the first chemical solution with pure water. A second chemical solution process of supplying a second chemical solution (for example, a chemical solution for resist removal: SPM) to the surface of the substrate W and a second rinse process of rinsing the second chemical solution with pure water may be performed.

  In this case, it is desirable that the substrate processing apparatus 1 perform the charge control process corresponding to each rinse process. FIG. 8 is a flowchart showing an example of the operation of the substrate processing apparatus 1. First, in step S11, the substrate W is carried into the substrate processing apparatus 1 and held by the substrate holding unit 10. Next, in step S12, the control unit 50 executes a first chemical liquid process. Specifically, the control unit 50 controls the rotation mechanism 13 to rotate the substrate holding unit 10 and the substrate W, and controls the chemical solution supply unit to supply the first chemical solution to the surface of the substrate W. When the first chemical liquid process is completed, the controller 50 executes a rinse process in step S13. This rinse process is the same as the rinse process of step S3. When the rinse process is completed, the control unit 50 executes the charge control process in step S14. This charge control process is similar to the charge control process of step S4. Thereby, the surface potential of the substrate W can be appropriately brought close to zero.

  When the charge control process is finished, the controller 50 executes the second chemical process in step S15. Specifically, the control unit 50 controls the chemical solution supply unit to supply the second chemical solution to the surface of the substrate W while controlling the rotation mechanism 13 to rotate the substrate W. The specific resistance of the second chemical solution is smaller than that of pure water, and when the absolute value of the surface potential of the substrate W is high, there is a possibility that a discharge or a large current may occur between the second chemical solution and the substrate. However, since the surface potential of the substrate W at the time of performing the second chemical liquid process approaches zero by the charge control process of step S14, generation of a discharge or a large current in the second chemical liquid process can be suppressed or avoided.

  When the second chemical liquid process is ended, the control unit 50 executes the rinse process and the charge control process in steps S16 and S17. These are the same as steps S3 and S4, respectively. Next, in step S18, the control unit 50 performs a drying process, and the substrate W is unloaded in step S19. Steps S18 and S19 are the same as steps S5 and S6, respectively.

<Period of rinse and charge control processing>
In the above-described example, the charge control process is performed after the rinse process. That is, after the supply of pure water to the front surface of the substrate W is finished, the supply of pure water to the back surface of the substrate W is started. However, the start order of the rinse process and the charge control process may be reversed. That is, the rinse process may be started after the charge control process is completed. In short, the execution order of steps S3 and S4, the execution order of steps S13 and S14, and the execution order of steps S16 and S17 may be reversed.

  The rinse process and the charge control process may be performed in parallel. In short, steps S3 and S4 may be performed in parallel, steps S13 and S14 may be performed in parallel, and steps S16 and S17 may be performed in parallel. In other words, at least a part of the supply period of pure water to the front surface of the substrate W (that is, the execution period of the rinse process) is at least the supply period of pure water to the rear surface of the substrate W (that is, the execution period of the charge control process). It may overlap with part.

  Thus, by simultaneously supplying pure water to the front surface and the back surface of the substrate W, the processing throughput can be improved. Even when the rinse process and the charge control process are performed in parallel, either of the rinse process and the charge control process may be started earlier or may be simultaneously performed.

<Distribution of surface potential>
As illustrated in FIG. 4, the surface potential in the vicinity of the peripheral edge of the substrate W becomes higher than the surface potential in the vicinity of the center of the substrate W by the rinse process (supply of pure water to the surface of the substrate W). In other words, a relatively large amount of negative charge is accumulated near the center of the substrate W, whereas a relatively small amount of negative charge is accumulated near the periphery of the substrate W, or rather near the periphery of the substrate W Positive charge is accumulated. It is considered that this is because the position at which pure water is applied to the surface of the substrate W is the central portion (specifically, the center) of the substrate W.

  On the other hand, as illustrated in FIG. 6, the surface potential of the substrate W is increased by a substantially constant amount regardless of the position of the substrate W by the charge control process (supply of pure water to the back surface of the substrate W). I know what to do. Therefore, the absolute value of the surface potential in the vicinity of the periphery of the substrate W is higher than the surface potential in the vicinity of the center.

  Therefore, in order to suppress an increase in the surface potential near the periphery of the substrate W, the substrate processing apparatus 1 may cause pure water to be deposited not only on the central portion but also on the peripheral portion of the surface of the substrate W in the rinse process. . Here, the peripheral portion is a region where the surface potential is higher than that of the central portion.

  The surface side pure water supply unit 20 shown in FIG. 1 is capable of depositing pure water on the central portion (specifically, the center) of the surface of the substrate W and the peripheral portion of the surface of the substrate W. This is because the nozzle moving mechanism 24 can move the nozzle 21 along the horizontal plane. Specifically, the pure water from the nozzle 21 can be made to come into contact with the central portion of the substrate W by stopping the nozzle 21 at a position facing the central portion of the substrate W in the vertical direction. . In addition, the nozzle moving mechanism 24 stops the nozzle 21 at a position facing the peripheral portion of the substrate W in the vertical direction, so that pure water from the nozzle 21 can be made to come into contact with the peripheral portion of the substrate W.

  FIG. 9 is a flowchart showing an example of the operation in the rinse process of the substrate processing apparatus 1. In the rinse process, the control unit 50 controls the rotation mechanism 13 to rotate the substrate holding unit 10 and the substrate W. In step S31, the control unit 50 controls the nozzle moving mechanism 24 to move the nozzle 21 to a position facing the central portion of the substrate W. Next, in step S32, the control unit 50 opens the on-off valve 23 to start the supply of pure water. Thus, pure water is discharged from the discharge port 21a of the nozzle 21 toward the central portion of the surface of the substrate W, and liquid is deposited on the central portion. Pure water deposited on the central portion of the substrate W receives centrifugal force, spreads over the entire surface of the substrate W, and scatters from the peripheral edge of the substrate W to the cup 60 side. Thus, the drug solution is washed away.

  When the elapsed time from the time of opening the on-off valve 23 exceeds the second predetermined time, in step S33, the control unit 50 controls the nozzle moving mechanism 24 so that the nozzle 21 faces the peripheral portion of the substrate W Move to the desired position. As a result, pure water is discharged from the discharge port 21 a of the nozzle 21 toward the peripheral edge portion of the surface of the substrate W to be deposited on the peripheral edge portion. The pure water deposited on the peripheral portion of the substrate W receives centrifugal force, moves toward the peripheral side of the substrate W, and scatters into the cup 60. As pure water is deposited on the peripheral portion of the surface of the substrate W, negative charges are accumulated also on the peripheral portion of the surface of the substrate W. Thus, the surface potential at the peripheral portion of the surface of the substrate W can be made close to the surface potential at the central portion thereof. That is, the surface potential of the substrate W after the rinse process can be made uniform.

  The surface potential at the peripheral portion of the surface of the substrate W decreases with the passage of time in the liquid immersion of pure water to the peripheral portion, and eventually approaches a value corresponding to the flow rate. Therefore, the controller 50 controls the substrate W in the supply period (the fourth predetermined time) in which the difference between the surface potential at the central portion of the substrate W and the surface potential at the peripheral portion of the substrate W is smaller than the potential difference reference value. Supply to the peripheral part of the surface of The supply period can be set in advance, for example, by simulation or experiment.

  When the elapsed time from step S33 exceeds the fourth predetermined time, in step S34, the control unit 50 closes the on-off valve 23 to end the supply of pure water to the surface of the substrate W.

  By such a rinse process, the surface of the substrate W is more uniformly negatively charged. Then, by performing charge control processing on this substrate W, the surface potential of this substrate W can be approximately increased by a substantially constant amount regardless of the position thereof, so the absolute value of the surface potential of substrate W Can be reduced uniformly. In other words, the surface potential can be uniformly brought close to zero over the entire surface of the substrate W.

  In the above-described example, the nozzles 21 are stopped at two different positions in the radial direction of the substrate W, and pure water is applied to the two positions (the central portion and the peripheral portion) of the surface of the substrate W. The position at which the nozzle 21 is stopped is not limited to two. The nozzles 21 may be stopped at three or more mutually different locations in the radial direction, and pure water may be deposited on three or more locations on the surface of the substrate W. In this case, the control unit 50 sends the surface side pure water supply unit 20 to each liquid deposition position under the supply condition in which the difference between the surface potential at each liquid deposition position and the surface potential at the central portion becomes smaller than the reference value. Supply pure water. According to this, the surface potential of the substrate W can be made finer and uniform.

  Further, in the above-described example, the nozzle moving mechanism 24 moves the nozzle 21. Therefore, the position at which the nozzle 21 is stopped can be easily changed, and the liquid deposition position can be easily changed later. For example, it is possible to make the landing position different for each substrate W.

  In the above-described example, although the flow rate of pure water discharged to the central portion of the substrate W and the flow rate of pure water discharged to the peripheral portion are the same, they may be different. For example, a flow control valve may be provided in the middle of the pipe 22. The flow rate adjustment valve is controlled by the control unit 50. The flow rate and supply period of pure water discharged to the peripheral portion of the substrate W are set in advance, for example, by simulation or experiment so that the difference in surface potential between the central portion and the peripheral portion of the substrate W becomes smaller than the potential difference reference value. It may be set.

<Multiple nozzles>
In the above-described example, the nozzle 21 is moved between the central position and the peripheral position in order to deposit pure water on the central portion and the peripheral portion of the surface of the substrate W. However, it is not necessary to move the nozzle 21 necessarily. For example, a nozzle for discharging pure water toward the central portion of the surface of the substrate W and a nozzle for discharging pure water toward the peripheral portion of the surface of the substrate W may be provided.

  FIG. 10 is a view schematically showing an example of the configuration of the surface side pure water supply unit 20A. The surface-side pure water supply unit 20A includes nozzles 21A and 21B, pipes 22A and 22B, and on-off valves 23A and 23B. The nozzles 21A and 21B are located above the substrate W when the rinse process is performed, and both face the surface of the substrate W. The nozzles 21A and 21B are disposed at mutually different positions in the radial direction when the rinse process is performed. Specifically, the nozzle 21A is disposed at a central position facing the central portion of the surface of the substrate W, and the nozzle 21B is disposed at a peripheral position facing the peripheral portion of the surface of the substrate W.

  One end of each of the pipes 22A and 22B is connected to the nozzles 21A and 21B, and the other end of each of the pipes 22A and 22B is connected to the pure water supply source 25. The on-off valves 23A and 23B are provided in the middle of the pipes 22A and 22B, respectively, and switch discharge / stop of the pure water from the corresponding nozzles 21.

  The nozzle moving mechanism 24 can reciprocate the nozzle 21A between the central position (first pure water treatment position) and the first pure water standby position, and the peripheral position of the nozzle 21B (second pure water treatment position) And the second pure water standby position. For example, the nozzles 21A and 21B may be connected to each other and their relative positions may be fixed. In this case, the nozzle moving mechanism 24 can move the nozzles 21A and 21B integrally.

  Also in the front side pure water supply unit 20A, pure water can be deposited on the central portion of the surface of the substrate W, and pure water can be deposited on the peripheral portion of the surface of the substrate W. For example, when the control unit 50 opens the on-off valve 23A, pure water can be deposited on the central portion of the surface of the substrate W, and on the peripheral portion of the surface of the substrate W by opening the on-off valve 23B. It can be allowed to settle.

  In the rinse process, the control unit 50 can cause pure water to be deposited only on the central portion of the surface of the substrate W, for example, by opening the on-off valve 23A and closing the on-off valve 23B. The pure water deposited on the central portion spreads by centrifugal force and spreads from the peripheral edge of the substrate W to the cup 60, so that the chemical solution on the surface of the substrate W can be washed away.

  The control unit 50 closes the on-off valve 23A and opens the on-off valve 23B, for example, when the elapsed time from the time when the on-off valve 23A is opened exceeds the second predetermined time. Thereby, pure water can be deposited only on the peripheral portion of the surface of the substrate W. The pure water receives centrifugal force, flows to the peripheral side of the substrate W, and scatters into the cup 60. The surface potential at the peripheral portion can be made close to the surface potential at the central portion by the application of the pure water to the peripheral portion. The surface potential at the peripheral portion decreases with the passage of time in the solution of pure water at the peripheral portion and eventually approaches the value according to the flow rate. The control unit 50 closes the on-off valve 23B when the fourth predetermined period has elapsed from the start of the deposition of pure water on the peripheral portion of the surface of the substrate W.

  Also by this, the surface potential of the substrate W after the rinse process can be made uniform. Therefore, the surface potential can be uniformly brought close to zero over the entire surface of the substrate W by performing the charge control process.

  Although two nozzles 21A and 21B are provided in the above-described example, three or more nozzles 21 disposed at mutually different positions in the radial direction may be provided. According to this, the surface potential can be made finer more uniformly.

<Surface potential measurement unit>
FIG. 11 is a diagram schematically showing an example of the configuration of the substrate processing apparatus 1A. The substrate processing apparatus 1A of FIG. 11 is different from the substrate processing apparatus 1 in that the surface potential measuring unit 80 is present. In other words, the substrate processing apparatus 1A further includes the surface potential measurement unit 80.

  The surface potential measurement unit 80 measures the surface potential of the substrate W, and outputs the measured value to the control unit 50. For example, the surface potential measurement unit 80 is provided with a non-contact type surface electrometer 81 and an electrometer moving mechanism 82. The surface potentiometer 81 is located above the substrate W at the time of measurement. For example, the surface potentiometer 81 has a probe. The probe contains an electrode. At the time of measurement, the distance between the tip of the probe and the main surface of the substrate W is set to about several [mm] (for example, 5 [mm]) or less. The surface potentiometer 81 measures the surface potential of the portion facing the probe based on the voltage generated at the electrode of the probe.

  The electrometer moving mechanism 82 is controlled by the control unit 50 to reciprocate the surface electrometer 81 between the measurement position and the electrometer standby position. The measurement position is an upper side of the substrate W held by the substrate holder 10, and is a position facing, for example, a central portion (a portion other than the peripheral portion) of the surface of the substrate W. The electrometer standby position is a position not facing the substrate W held by the substrate holder 10 in the vertical direction. When the surface potentiometer 81 is stopped at the potentiometer standby position, the transfer of the substrate W between the external substrate transfer unit and the substrate holding unit 10 is not inhibited. An example of a specific configuration of the electrometer moving mechanism 82 is the same as the nozzle moving mechanism 24.

  The control unit 50 determines whether to end the charge control processing based on the surface potential measured by the surface voltmeter 81. That is, the control unit 50 determines whether the supply of pure water to the back surface of the substrate W is ended based on the surface potential measured by the surface voltmeter 81. Specifically, the control unit 50 determines whether the absolute value of the surface potential measured by the surface voltmeter 81 is smaller than the potential reference value, and the absolute value of the surface potential is smaller than the potential reference value. When it is determined, the charge control process (supply of pure water to the back surface) may be ended. Alternatively, when the surface voltmeter 81 measures the surface potential at the peripheral portion, the control unit 50 determines whether the surface potential is within a predetermined range, and terminates the charging process when an affirmative determination is made. You may In this case, the predetermined range may be set in advance as follows. That is, the predetermined range may be set in advance so that the absolute value of the surface potential in the central portion is smaller than the potential reference value.

  FIG. 12 is a flowchart showing an example of the operation in the charge control process of the substrate processing apparatus 1A. Also in this charging control process, as described above, the control unit 50 controls the rotation mechanism 13 to rotate the substrate holding unit 10 and the substrate W. In step S40, control unit 50 controls electrometer moving mechanism 82 to move surface electrometer 81 to the measurement position. Next, in step S41, the control unit 50 opens the on-off valve 33 to start the supply of pure water to the back surface of the substrate W. The supply of pure water to the back surface of the substrate W causes the surface potential of the substrate W to increase substantially uniformly over the entire surface.

  Next, in step S42, the surface potentiometer 81 measures the surface potential of the substrate W, and outputs the measured value to the control unit 50. Here, the surface potentiometer 81 measures the surface potential at a position closer to the center than the peripheral portion of the substrate W. Next, at step S43, the control unit 50 determines whether the absolute value of the surface potential measured by the surface voltmeter 81 is smaller than the potential reference value. The potential reference value is set in advance, for example, and stored in the storage unit of the control unit 50.

  If it is determined that the absolute value of the surface potential is larger than the potential reference value, control unit 50 executes step S42 again (NO in step S42). That is, in this case, since the surface potential of the substrate W has not yet approached the desired value, the supply of pure water to the back surface of the substrate W is continued.

  When it is determined in step S43 that the absolute value of the surface potential is smaller than the potential reference value, in step S44, the control unit 50 closes the on-off valve 33 and ends the supply of pure water to the back surface of the substrate W. That is, in this case, the control unit 50 ends the charge control process because it is not necessary to supply more pure water. Next, in step S45, the control unit 50 controls the electrometer moving mechanism 82 to move the surface electrometer 81 to the standby position.

  As described above, according to the substrate processing apparatus 1A, the surface potential measurement unit 80 measures the surface potential of the substrate W, and the control unit 50 determines whether it is necessary to end the charge control processing based on the surface potential. Therefore, the surface potential of the substrate W can be controlled with higher accuracy.

<Distribution of surface potential>
Next, application in the case where the surface potential of the substrate W after the rinse process is made uniform by changing the liquid deposition position on the surface of the substrate W in the rinse process will be described. Here, in this rinse process, it is contemplated to measure the distribution of the surface potential of the substrate W and perform processing using the measured surface potential. The details will be described below.

  The surface potential measurement unit 80 measures the surface potential of the substrate W at mutually different positions in the radial direction centering on the rotation axis of the substrate W. For example, the surface potential measurement unit 80 measures the surface potential at the central portion on the central side of the substrate W and the surface potential at the peripheral portion on the peripheral side of the substrate W. Specifically, the control unit 50 controls the electrometer moving mechanism 82 to move the surface electrometer 81 to a position facing the central portion of the substrate W (hereinafter referred to as a central measurement position), whereby the surface potential is obtained. A total of 81 measures the surface potential at the central portion. Further, the control unit 50 moves the surface potentiometer 81 to a position facing the peripheral portion of the substrate W (hereinafter referred to as a peripheral measurement position), whereby the surface potentiometer 81 measures the surface potential at the peripheral portion.

  The position on the substrate W to be measured by the surface potential measurement unit 80 is preferably at the same position or in the vicinity of the position where the pure water is deposited from the nozzle 21 in the radial direction. For example, when the nozzle 21 causes pure water to come into contact with the peripheral portion of the substrate W, the surface potential measurement unit 80 measures the surface potential at the same position in the radial direction as the liquid application position.

  The control unit 50 determines whether or not the supply of pure water to the peripheral portion of the front surface of the substrate W is ended in the rinse process based on the difference in surface potential between the central portion and the peripheral portion measured by the surface potential measuring unit 80. Determine based on.

  FIG. 13 is a flowchart showing an example of the operation in the rinse process of the substrate processing apparatus 1A. Also in this rinse process, the control unit 50 controls the rotation mechanism 13 to rotate the substrate holding unit 10 and the substrate W. In step S301, the control unit 50 controls the nozzle moving mechanism 24 to move the nozzle 21 to a central position facing the central portion of the substrate W. Next, in step S302, the control unit 50 opens the on-off valve 23 to start the supply of pure water. As a result, pure water is discharged from the discharge port 21 a of the nozzle 21 toward the central portion of the surface of the substrate W to be deposited on the central portion. The pure water deposited on the central portion receives centrifugal force, spreads over the entire surface of the substrate W, and is scattered from the peripheral edge.

  When the elapsed time from the time of opening the on-off valve 23 exceeds the second predetermined time, in step S303, the control unit 50 controls the nozzle moving mechanism 24 so that the nozzle 21 faces the peripheral portion of the substrate W To the peripheral position. Thereby, the pure water discharged from the discharge port 21 a of the nozzle 21 comes in contact with the peripheral portion of the substrate W. The pure water deposited on the peripheral portion of the substrate W receives centrifugal force, moves toward the peripheral side of the substrate W, and scatters into the cup 60. As pure water is deposited on the peripheral portion of the substrate W, negative charges are accumulated also on the peripheral portion of the substrate W.

  Next, in step S304, the surface potential measurement unit 80 measures the surface potential Va of the central portion of the substrate W and the surface potential Vb of the peripheral portion, and outputs the measured values to the control unit 50. Specifically, the surface potentiometer 81 measures the surface potential Va at the central measurement position, and outputs this to the control unit 50. Next, the control unit 50 controls the electrometer moving mechanism 82 to move the surface electrometer 81 to the peripheral measurement position. The surface potentiometer 81 measures the surface potential Vb in this state, and outputs the measured value to the control unit 50. The order of measurement may be reversed.

  Next, in step S305, control unit 50 determines whether the difference between surface potentials Va and Vb (= | Va-Vb |) is smaller than a reference value. The reference value is set in advance, for example, and stored in the storage unit of the control unit 50.

  If it is determined that the difference between surface potentials Va and Vb is larger than the reference value, control unit 50 executes step S304 again (NO in step S305). That is, when the difference between the surface potentials Va and Vb is larger than the reference value, it is determined that the surface potential has not been sufficiently uniform, and the supply of pure water to the peripheral portion of the substrate W is maintained.

  When it is determined in step S305 that the difference between the surface potentials Va and Vb is smaller than the reference value, the control unit 50 closes the on-off valve 23 in step S306 to complete the supply of pure water. That is, when the difference between the surface potentials Va and Vb is smaller than the reference value, it is judged that the surface potential has been made uniform enough, and the supply of pure water to the peripheral portion of the surface of the substrate W is ended.

  According to this operation, the surface potential measurement unit 80 measures the surface potential of the central portion and the peripheral portion of the substrate W, and the control unit 50 ends the supply of pure water to the peripheral portion of the surface of the substrate W Based on the difference between Therefore, the surface potential can be made uniform with higher accuracy.

  In the above-mentioned example, although two places of a center part and a peripheral part are adopted as a main liquid landing position on the surface of substrate W, more parts may be adopted. In this case, the surface potential measurement unit 80 measures the surface potential at the same position (including the vicinity thereof) in the radial direction as each liquid deposition position. Then, the control unit 50 determines whether the supply of pure water at each liquid deposition position (excluding the central portion) is ended based on the difference between the surface potential at the liquid deposition position and the surface potential at the central portion. You may judge. Specifically, when the potential difference is smaller than the reference value, the control unit 50 ends the supply of pure water to the liquid deposition position.

  Further, in the above-mentioned example, the electrometer moving mechanism 82 moves the surface electrometer 81, whereby the surface electrometer 81 measures the surface potential at each liquid deposition position. In this case, since the position of the surface voltmeter 81 is not fixed, the measurement position can be easily changed.

<Multiple surface voltmeters>
FIG. 14 schematically shows an example of the configuration of surface side pure water supply unit 20 and surface potential measurement unit 80. Referring to FIG. In the example of FIG. 14, the surface potential measurement unit 80 includes surface potentiometers 81A and 81B. The surface voltmeter 81B is disposed at a position facing the peripheral portion of the surface of the substrate W at the time of measurement. The surface voltmeter 81 B measures the surface potential Vb in the peripheral portion, and outputs the measured value to the control unit 50. The surface potentiometer 81A is located closer to the center of the substrate W than the surface potentiometer 81B at the time of measurement. The surface potentiometer 81 A measures the surface potential Va at the central portion of the substrate W, and outputs the measured value to the control unit 50. The surface potentiometers 81A and 81B are moved to their respective standby positions by the potentiometer moving mechanism 82 when not measuring.

  In the example of FIG. 14, the nozzle 21 stopped at the central position facing the central portion of the substrate W is shown by a solid line, and the nozzle 21 stopped at the peripheral position facing the peripheral portion of the substrate W is shown by a two-dot chain line. It is done.

  The control unit 50 determines whether or not the supply of pure water to the peripheral portion of the surface of the substrate W is ended in the rinse process based on the measurement results of the surface potentiometers 81A and 81B. More specifically, control unit 50 determines whether the difference between surface potentials Va and Vb measured by surface voltmeters 81A and 81B is smaller than a reference value, and the difference between surface potentials Va and Vb is a reference value. When it is determined that the size is smaller than the above, the supply of pure water to the peripheral portion is ended.

  Since the plurality of surface potentiometers 81A and 81B are provided, it is not necessary to move the surface potentiometer 81 when measuring the surface potentials Va and Vb, and the surface potentials Va and Vb can be measured at the same time. Therefore, it is possible to determine the end of the supply of the pure water to the peripheral portion with high responsiveness. Further, since the number of times of driving the electrometer moving mechanism 82 can be reduced, the life of the substrate processing apparatus 1 can be extended.

  In the above-mentioned example, although two surface electrometers 81A and 81B are provided, when there are three or more positions to be measured, the surface electrometers 81 of the number corresponding to the positions of the measurement object are provided. Just do it.

<Back side pure water supply unit>
With reference to FIGS. 4 and 6, although the surface potential of the substrate W is increased by a substantially constant amount due to the supply of pure water to the back surface of the substrate W by the back surface side pure water supply unit 30, FIG. Comparing FIG. 4 and FIG. 6, it can be seen that the surface potential is more increased in the central portion of the substrate W. This can be considered as the nozzle 31 of the back surface side pure water supply unit 30 deposits pure water on the central portion of the back surface of the substrate W. That is, the surface potential at the position corresponding to the liquid deposition position on the back surface of the substrate W is considered to increase by a larger increase than the surface potential at the other positions.

  Now, in the substrate processing apparatus 1A, pure water is made to adhere to the peripheral portion of the surface of the substrate W by the surface side pure water supply unit 20, so that the surface potential at this peripheral portion is about the same as the surface potential at the central portion It has been described that it can be reduced to However, it is also conceivable that the surface potential at the peripheral portion of the substrate W becomes smaller than the surface potential of the substrate W if, for example, the supply period of pure water to be deposited on the peripheral portion of the surface of the substrate W becomes too long.

  Therefore, it is intended to eliminate such a drop in the surface potential at the peripheral portion of the substrate W by depositing pure water on the peripheral portion of the back surface of the substrate W. FIG. 15 is a diagram schematically showing an example of the configuration of the substrate processing apparatus 1B. The substrate processing apparatus 1B of FIG. 15 is different from the substrate processing apparatus 1A in the configuration of the back surface side pure water supply unit 30. In the substrate processing apparatus 1B, the back surface side pure water supply unit 30 can cause pure water to be deposited at a plurality of positions on the back surface of the substrate W. For example, the back side pure water supply unit 30 includes nozzles 31A and 31B, pipes 32A and 32B, and on-off valves 33A and 33B.

  In the base 11, holes 111A and 111B are formed corresponding to the nozzles 31A and 31B, respectively. The hole 111A is formed at a position opposed in the vertical direction to a central portion (for example, the center) of the back surface of the substrate W, and the hole 111B is formed at a position opposed in the vertical direction to the peripheral portion of the back surface of the substrate W There is. The holes 111A and 111B penetrate the base 11 in the vertical direction.

  The nozzles 31A and 31B are arranged such that their respective discharge ports 31a face the back side of the substrate W. The nozzle 31A is inserted into the hole 111A, and discharges the pure water toward the central portion of the back surface of the substrate W. The nozzle 31B is inserted into the hole 111B and discharges pure water toward the peripheral portion of the back surface of the substrate W.

  One end of each of the pipes 32A and 32B is connected to the nozzles 31A and 31B, and the other end is connected to the pure water supply source 25. One set of the nozzle 31A and the pipe 32A penetrates the hole 111A, and one set of the nozzle 31B and the pipe 32B penetrates the hole 111B. The on-off valves 33A and 33B are provided in the middle of the pipes 32A and 32B, respectively, and switch the discharge / stop of the pure water from the nozzles 31A and 31B, respectively. The on-off valves 33A and 33B are controlled by the control unit 50.

  The back surface side pure water supply unit 30 supplies the pure water to the central portion of the back surface of the substrate W and the pure water to the peripheral portion of the back surface of the substrate W in the charge control process. Thereby, when the surface potential of the substrate W is lower at the peripheral portion than at the central portion, the difference in the surface potential can be reduced, and the surface potential can be made to approach zero uniformly.

  FIG. 16 is a flowchart showing an example of the operation in the charge control process of the substrate processing apparatus 1B. Here, initially, the surface potential of the substrate W is lower in the peripheral portion than in the central portion. In addition, also in this charge control process, the control unit 50 controls the rotation mechanism 13 to rotate the substrate holding unit 10 and the substrate W. First, in step S400, the control unit 50 controls the electrometer moving mechanism 82 to move the surface electrometer 81 (81A, 81B) to the measurement position. Next, in step S401, the control unit 50 opens the on-off valve 33A to discharge pure water from the nozzle 31. The pure water is deposited on the central portion of the back surface of the substrate W, receives centrifugal force, spreads along the back surface, and scatters from the peripheral edge of the substrate W to the cup 60 side. Thereby, the surface potential of the substrate W is entirely increased.

  Next, in step S402, for example, the surface potentiometer 81 (81A) measures the surface potential Va at the central portion of the substrate W, and outputs the measured value to the control unit 50. Next, in step S403, control unit 50 determines whether the absolute value of surface potential Va is smaller than the potential reference value. If a negative judgment is made, control part 50 will perform Step S402 again.

  When an affirmative determination is made in step S402, in step S404, the control unit 50 closes the on-off valve 33A to stop the discharge of the pure water from the nozzle 31A. Next, in step S405, the control unit 50 opens the on-off valve 33B to discharge pure water from the nozzle 31B. Pure water is deposited on the peripheral portion of the back surface of the substrate W, and is scattered from the peripheral edge of the substrate W to the cup 60 side under centrifugal force. Thereby, the surface potential Vb at the peripheral portion of the substrate W increases and approaches the surface potential Va at the central portion.

  Next, in step S406, the surface potentiometer 81 (81B) measures the surface potential Vb at the peripheral portion of the substrate W, and outputs the measured value to the control unit 50. Next, in step S407, control unit 50 determines whether the difference (= | Va-Vb |) between surface potentials Va and Vb is smaller than a reference value. If it is determined that the difference between surface potentials Va and Vb is larger than the reference value, control unit 50 executes step S406 again (NO in step S407). That is, when the surface potential Vb in the peripheral portion is not sufficiently close to the surface potential Va in the central portion, the supply of pure water to the peripheral portion of the back surface of the substrate W is maintained.

  If it is determined in step S407 that the difference between the surface potentials Va and Vb is smaller than the reference value, the control unit 50 closes the on-off valve 33B in step S408 and ends the supply of pure water to the back surface of the substrate W. .

  As described above, according to the substrate processing apparatus 1B, even if the surface potential Vb of the peripheral portion of the substrate W is smaller than the surface potential Vb of the central portion of the substrate W, the difference between these surface potentials is reduced The potential can be made uniform.

  In the above-mentioned example, although the flow rate of the pure water discharged from nozzles 31A and 31B is the same, it is not necessarily limited to this. For example, by providing a flow rate adjustment valve in the middle of the pipe 32, the flow rate of pure water discharged from the nozzles 31A and 31B may be made different.

  In the above-mentioned example, although back side pure water supply part 30 has two nozzles 31A and 31B, it may have three or more nozzles 31. The positions of the three or more nozzles 31 in the radial direction are different from each other, and pure water can be deposited on the back surface of the substrate W at different positions in the radial direction. In this case, the surface potential measurement unit 80 measures the surface potential at a position corresponding to the position where pure water is applied to the back surface of the substrate W. Then, the control unit 50 determines whether the supply of pure water at each liquid deposition position is ended based on the difference between the surface potential corresponding to each liquid deposition position and the surface potential at the central portion. Thereby, the surface potential can be more finely made uniform.

  Moreover, although the back surface side pure-water supply part 30 has the some nozzle 31 in the above-mentioned example, it does not necessarily restrict to this. For example, it may be a nozzle extending in the radial direction of the substrate W, and a plurality of discharge ports may be formed on the discharge surface thereof. Alternatively, the back surface side pure water supply unit 30 may be provided with a nozzle moving mechanism that moves the nozzle 31 along a horizontal surface.

  FIG. 17 is a diagram showing an example of the configuration of the back side pure water supply unit 30A. The back surface side pure water supply unit 30A of FIG. 17 is different from the back surface side pure water supply unit 30 of FIG. 1 in that the nozzle moving mechanism 34 is provided. That is, the back surface side pure water supply unit 30A further includes the nozzle moving mechanism 34.

  The nozzle moving mechanism 34 moves the nozzle 31 to a position where pure water is deposited on the central portion of the back surface of the substrate W and a position where pure water is deposited on the peripheral portion of the back surface of the substrate W. For example, the nozzle moving mechanism 34 moves the nozzle 31 horizontally along the back surface of the substrate W between these positions.

  In this case, a space for securing the movement path of the nozzle 31 is formed in the substrate holding unit 10 and the rotation mechanism 13. For example, when the hole 111 formed in the substrate holding unit 10 is formed so as to include the movement path of the nozzle 31 and the rotation mechanism 13 has a hollow motor, the hollow portion of the hollow motor includes the movement path of the nozzle 31 Formed as.

  The nozzle moving mechanism 34 is controlled by the control unit 50 and, for example, a ball screw extending in the horizontal direction, a motor for rotating the ball screw, a nut moving along the ball screw with the rotation of the ball screw, and the nut And a connecting member for connecting the nozzle.

  According to the back surface side pure water supply unit 30A, when the nozzle 31 is stopped at a position facing the center portion of the back surface of the substrate W, the center portion can be made to deposit pure water, and the nozzle 31 is the substrate By stopping at a position facing the peripheral portion of W, pure water can be deposited on the peripheral portion. Further, the liquid deposition position can be easily changed to the position by the movement of the nozzle 31.

First Modified Example
In the above-described example, the surface potential of the substrate W is brought close to zero by the rinse process and the charge control process of the substrate processing apparatus 1 (1A, 1B). However, the surface potential of the substrate W may be brought close to a predetermined value other than zero. For example, when ion etching is performed on the surface of the substrate W in a later step of the substrate processing apparatus 1 (1A, 1B), the etching rate changes according to the charge amount of the surface of the substrate W. Therefore, the surface potential of the substrate W may be brought close to a predetermined value by the rinse process and the charge control process of the substrate processing apparatus 1 (1A, 1B) in order to set the etching rate in the post-process to a predetermined rate.

Second Modified Example
The substrate W processed by the substrate processing apparatus 1 may be carried out by an external substrate transfer unit, and the surface potential of the substrate W may be measured by an external inspection apparatus. Then, when the inspection apparatus determines that the reprocessing of the substrate W is necessary based on the surface potential of the substrate W, the substrate transport unit may carry the substrate W into the substrate processing apparatus 1 again.

  The control unit 50 transmits, from the inspection apparatus, information indicating that the carried-in substrate W is a substrate to be reprocessed and a measurement value of the surface potential of the substrate W. The control unit 50 determines supply conditions for pure water to be supplied to the front surface of the substrate W and supply conditions for pure water to be supplied to the back surface of the substrate W based on the measured values. For example, when the measured value of the surface potential of the substrate W is smaller than the lower limit value of the predetermined range, the flow rate and supply period of pure water supplied to the surface of the substrate W are determined to be zero. The flow rate and supply period of pure water to be supplied are determined according to the difference between the lower limit value and the measurement value. The control unit 50 determines the flow rate of pure water to the rear surface more as the difference is larger, or determines the supply period longer. The relationship between the difference, the flow rate, and the supply period is set in advance, for example, by simulation or experiment, and stored in the storage unit of the control unit 50.

  Then, the control unit 50 controls the front side pure water supply unit 20 and the back side pure water supply unit 30 to supply pure water to the front surface or the back surface of the substrate W at the determined flow rate.

  According to this, even if it is difficult to provide the surface potential measurement unit 80 in the processing chamber of the substrate processing apparatus 1, the surface potential of the substrate W can be controlled with higher accuracy.

Third Modified Example
As illustrated in FIG. 3, when the surface of the substrate W is charged, the charge state of the surface affects the electric state of the back surface. Specifically, as the charge amount (negative charge amount) on the surface of the substrate W is larger, more positive charges appear on the back surface of the substrate W. Therefore, by measuring the potential of the back surface of the substrate W, the charged state of the surface of the substrate W can be estimated.

  FIG. 18 is a diagram schematically showing an example of the configuration of the substrate processing apparatus 1C. The substrate processing apparatus 1C is different from the substrate processing apparatus 1A in terms of the position of the surface potential measurement unit 80. In the substrate processing apparatus 1C, the surface potential measurement unit 80 is provided on the back side of the substrate W. The surface potential measuring unit 80 measures the potential of the back surface of the substrate W, and outputs the measured value to the control unit 50.

  For example, the surface potential measurement unit 80 measures the potential of the back surface of the substrate W after the rinse process, and outputs the measured value to the control unit 50. The control unit 50 estimates the surface potential of the substrate W based on the measurement value of the surface potential measurement unit 80. The relationship between the electric potential of the back surface of the substrate W and the surface electric potential of the substrate W can be set in advance, for example, by simulation or experiment, and is stored in the storage unit of the control unit 50. The control unit 50 estimates the surface potential of the substrate W based on the measurement value from the surface potential measurement unit 80 and the relation stored in the storage unit.

  Then, the control unit 50 may determine supply conditions for pure water to be supplied to the back surface of the substrate W in the charge control process based on the estimated surface potential. The relationship between the surface potential of the substrate W, the flow rate of pure water to be supplied in the charge control process, and the supply period can be set in advance by, for example, simulation or experiment, and stored in the storage unit of the control unit 50. The control unit 50 determines the supply conditions of pure water in the charge control process based on the estimated surface potential and the relationship stored in the storage unit.

  The various aspects described above can be combined with one another.

1, 1A to 1C Substrate processing apparatus 10 substrate holding means (substrate holding portion)
13 Rotation mechanism 20, 20A First pure water supply means (surface side pure water supply unit)
30, 30 A Second pure water supply means (rear side pure water supply unit)
31 nozzle 31A first nozzle (nozzle)
31B 2nd nozzle (nozzle)
50 Control means (control unit)
81 Surface potential meter 81A 1st surface potential meter (surface potential meter)
81 B Second surface potentiometer (surface potentiometer)
W substrate

Claims (16)

A substrate processing method for processing a substrate having a first main surface and a second main surface opposite to the first main surface,
Rotating the substrate in a horizontal plane (a);
Supplying pure water to the first main surface of the substrate after the step (a);
After the step (a), the flow rate and / or the supply period of the charge amount of the first main surface of the substrate charged due to the step (b) are smaller than the first reference value. And (c) supplying pure water to the second main surface. The substrate processing method according to claim 1,
A substrate processing method, wherein at least a part of the execution period of the step (b) and at least a part of the execution period of the step (c) overlap. The substrate processing method according to claim 1 or 2, wherein
In the step (c),
Measuring the surface potential of the first main surface of the substrate (c1);
And (c2) determining whether or not the supply of pure water to the second main surface of the substrate is ended based on the surface potential measured in the step (c1). The substrate processing method according to any one of claims 1 to 3, wherein
In the step (b),
Applying pure water to a first central portion of the first main surface of the substrate (b1);
A flow rate which makes the difference between the first surface potential in the first central portion and the second surface potential in the first peripheral portion on the peripheral side of the first central portion of the first main surface smaller than a second reference value And / or a step (b2) of depositing pure water on the first peripheral portion during the supply period. The substrate processing method according to claim 4,
In the step (b),
Measuring a first surface potential at the first central portion of the first main surface of the substrate and a second surface potential at the first peripheral portion (b3)
And further
In the step (b2), whether or not the supply of pure water to the first peripheral portion is ended is determined by the difference between the first surface potential measured in the step (b3) and the second surface potential. The substrate processing method to judge based on. The substrate processing method according to claim 5,
In the step (b3),
The surface electrometer measuring the first surface potential while the surface electrometer is moved to a position facing the first central portion of the first main surface;
And D. the surface electrometer measuring the second surface potential with the surface electrometer moved to a position facing the first peripheral portion of the first main surface. The substrate processing method according to claim 5,
In the step (b3),
A first surface voltmeter measuring the first surface potential;
And d. A second surface voltmeter different from the first surface voltmeter measuring the second surface potential. The substrate processing method according to any one of claims 4 to 7, wherein
In the step (c),
Applying pure water to a second central portion of the second main surface of the substrate (c1);
Pure water is applied to the second peripheral portion on the peripheral side of the second central portion of the second main surface at a flow rate and / or a supply period that reduces the difference between the first surface potential and the second surface potential. A substrate processing method comprising the step of (c2) immersing. The substrate processing method according to claim 8,
In the step (c1), the nozzle discharges the pure water toward the second central portion while moving the nozzle to a position facing the second central portion of the second main surface of the substrate. ,
In the step (c2), the nozzle discharges pure water toward the second peripheral portion while moving the nozzle to a position facing the second peripheral portion of the second main surface of the substrate. The substrate processing method. The substrate processing method according to claim 8,
In the step (c1), the first nozzle discharges pure water toward the second central portion of the second main surface of the substrate,
In the substrate processing method, in the step (c2), a second nozzle different from the first nozzle discharges pure water toward a second peripheral portion of the second main surface. The substrate processing method according to any one of claims 1 to 10, wherein
After the step (b) and the step (c) are both performed, the method further includes the step (d) of supplying a processing liquid having a smaller specific resistance than pure water to the first main surface of the substrate. , Substrate processing method. The substrate processing method according to any one of claims 1 to 11, wherein
A substrate processing method, wherein an insulating film and a metal film are formed on the first main surface of the substrate. The substrate processing method according to any one of claims 1 to 12,
The substrate processing method, wherein the specific resistance of the pure water is 10 [MΩ · cm] or more. A substrate processing method for processing a substrate having a first main surface on which an insulating film and a metal film are formed, and a second main surface opposite to the first main surface,
Rotating the substrate in a horizontal plane (a);
Supplying pure water to the first main surface of the substrate after the step (a);
Supplying pure water to the second major surface of the substrate after the step (a);
And (d) supplying a processing liquid having a smaller specific resistance than pure water to the first main surface of the substrate after both the step (b) and the step (c) are performed. , Substrate processing method. Substrate holding means for holding a substrate having a first main surface and a second main surface opposite to the first main surface,
A rotation mechanism for rotating the substrate holding means;
First pure water supply means for supplying pure water to the first main surface of the substrate;
Second pure water supply means for supplying pure water to the second main surface of the substrate;
The second pure water supply means has a flow rate and / or a supply period which makes the charge amount of the first main surface to be charged due to the supply of pure water to the first main surface lower than a first reference value A control unit for supplying pure water to the second main surface. The substrate processing apparatus according to claim 15.
The substrate processing apparatus, wherein the substrate holding means is grounded.

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