JP2013077664A - Substrate rear surface cleaning method and substrate rear surface cleaning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate rear surface cleaning method and a substrate rear surface cleaning apparatus which ensure and improve the rear surface washability for a substrate having a large diameter and reduce a rear surface cleaning liquid.SOLUTION: A substrate rear surface cleaning method includes: a cleaning liquid discharge process where a process liquid is supplied to a surface of a wafer rotating around a vertical shaft and then a cleaning liquid is supplied while the wafer is rotated at a first rotation rate so that the cleaning liquid is slowly diffused to a rear surface of the wafer; and a cleaning liquid drain process where the wafer is rotated at a second rotation rate faster than the first rotation rate to quickly diffuse and drain off the cleaning liquid on the rear surface of the wafer. These processes are alternately repeated several times.

Description

  The present invention relates to a substrate back surface cleaning method and a substrate back surface cleaning apparatus for cleaning the back surface of a substrate whose processing liquid is supplied to the front surface.

  In general, a photolithography process is used in a semiconductor manufacturing process. For example, a photoresist is applied on a substrate such as a semiconductor wafer (hereinafter referred to as a wafer), and the resist film is exposed according to a predetermined circuit pattern. The circuit pattern is formed by developing. In the photolithography process, a processing system in which an exposure apparatus is connected to a coating / development processing apparatus is usually used.

  In the photolithography process, a processing solution such as a photoresist solution or a developing solution is supplied to the surface of the substrate that rotates about the vertical axis, and the liquid film is expanded by centrifugal force. At this time, a spin cleaning method is known in which a cleaning liquid is supplied to the inner periphery of the back side of the substrate to remove the processing liquid in order to remove the processing liquid that wraps around the back surface of the substrate.

  As a conventional substrate back surface cleaning method (apparatus) of this type, a back surface cleaning nozzle is arranged at a fixed position on the inner peripheral side of the back surface of the substrate, and the tangential position in the rotation direction of the substrate with a constant number of substrate rotations. For example, a substrate backside cleaning process is performed by discharging a cleaning liquid (see, for example, Patent Document 1).

Japanese Patent No. 3485471 (Claims, FIG. 5)

  By the way, when the size of the wafer as a substrate is changed from an existing Φ300 mm wafer to a wafer having a large diameter (Φ450 mm), the backside cleaning method described in Patent Document 1 has a tendency to reduce the cleaning ability of the backside of the wafer. For example, in resist coating processing, ensuring the wafer backside cleanability is important as a countermeasure against defocus in exposure processing. Ensuring the wafer backside cleanability by increasing the diameter of the wafer can be complemented by extending the processing time of the backside cleaning, but there is a concern that a large amount of backside cleaning liquid is consumed.

  However, in recent years, demands for reducing the amount of chemicals are increasing from the viewpoint of resource saving and CO2 reduction, and countermeasures are required.

  The present invention has been made in view of the above circumstances, and is intended to ensure the back surface cleaning property and improve the back surface cleaning property for a large-diameter substrate, and to achieve a substrate back surface cleaning method capable of saving the back surface cleaning liquid. An object is to provide such a device.

  In order to solve the above-mentioned problems, the substrate back surface cleaning method according to the present invention is provided in the periphery of the back surface of the substrate while the substrate is rotated after the step of supplying the treatment liquid to the surface of the substrate rotating about the vertical axis. A cleaning step of supplying a cleaning solution to a plurality of positions on the substrate and cleaning the substrate, and the cleaning step rotates at a first rotational speed to supply the cleaning solution to gently diffuse the cleaning solution on the back surface of the substrate. A cleaning liquid discharging step and a cleaning liquid sprinkling step in which the cleaning liquid on the back surface of the substrate is rapidly diffused and spun off by rotating at a second rotational speed higher than the first rotational speed are alternately repeated a plurality of times. (Claim 1).

  In the substrate back surface cleaning method according to claim 1, it is preferable that the position where the cleaning liquid is supplied to the back surface of the substrate is a plurality of positions which are different in the radial direction in the inner periphery of the substrate (claim 2).

  In the substrate back surface cleaning method according to claim 1 or 2, the discharge angle of the cleaning liquid with respect to the back surface of the substrate may be made variable (claim 3).

  In the substrate back surface cleaning method according to claim 1 or 2, the discharge angle of the cleaning liquid with respect to the back surface of the substrate may be different at each position where the cleaning liquid is supplied to the back surface of the substrate (claim 4).

  5. The substrate back surface cleaning method according to claim 1, wherein the first rotational speed is preferably 10 to 120 rpm, and the second rotational speed is preferably 1000 to 3000 rpm (claim 5). In this case, it is preferable that the discharge time in the cleaning liquid discharge step is 2 to 5 seconds, and the swing-off time in the cleaning liquid swing-off step is 1 second.

  In the substrate backside cleaning method according to any one of claims 1 to 6, it is preferable to repeat the cleaning liquid discharge step and the cleaning liquid shaking step three times (claim 7).

  In the substrate back surface cleaning method according to claim 1, 2, 5, or 6, the discharge angle of the cleaning liquid with respect to the back surface of the substrate is variable, and the cleaning liquid discharging step and the cleaning liquid shaking step are repeated three times. It is preferable that the first to third discharge angles with respect to the substrate in the cleaning liquid discharge step be 45 °, 30 °, and 90 °.

  Further, in the substrate back surface cleaning method according to any one of claims 1 to 8, the discharge position of the cleaning liquid with respect to the back surface of the substrate may be variable along the radial direction of the substrate (claim 9).

  The substrate back surface cleaning method according to any one of claims 1 to 8, wherein a discharge position of the cleaning liquid with respect to the back surface of the substrate is variable along a radial direction of the substrate, the cleaning liquid discharging step, and the cleaning liquid shaking-off. It is preferable to repeat the process three times and set the first to third cleaning liquid discharge locations in the cleaning liquid discharge process to 75 mm, 55 mm, and 5 mm from the outer periphery of the substrate (claim 10).

  A substrate back surface cleaning apparatus according to the present invention embodies the substrate back surface cleaning method according to claim 1, and rotates a substrate holding unit that rotatably holds a substrate around a vertical axis. With respect to a plurality of positions inside the periphery of the back surface of the substrate rotated by the substrate holding unit, a rotation driving unit, a processing liquid supply nozzle for supplying a processing liquid to the surface of the substrate held by the substrate holding unit A back surface cleaning nozzle that supplies a cleaning liquid; and a control unit that controls rotation of the rotation driving unit and driving of the back surface cleaning nozzle, and the cleaning liquid is applied to the back surface of the substrate based on a signal from the control unit. A cleaning liquid discharge process for supplying a cleaning liquid by rotating at a first rotational speed for gentle diffusion, and a rapid diffusion of the cleaning liquid on the back surface of the substrate by rotating at a second rotational speed higher than the first rotational speed. And shake off A step shake-off, repeated a plurality of times alternately, characterized in that (claim 11).

  12. The substrate back surface cleaning apparatus according to claim 11, wherein a plurality of the back surface cleaning nozzles are provided, and each of the back surface cleaning nozzles preferably supplies a cleaning liquid to a plurality of radially different positions on the inner periphery of the substrate. (Claim 12).

  13. The substrate back surface cleaning apparatus according to claim 11 or 12, wherein the angle at which the back surface cleaning nozzle supplies the cleaning liquid to the back surface of the substrate is preferably variably formed (claim 13).

  13. The substrate back surface cleaning apparatus according to claim 11 or 12, wherein the back surface cleaning nozzle is formed so that a discharge angle of the cleaning liquid with respect to the back surface of the substrate is different at each position where the cleaning liquid is supplied to the back surface of the substrate. Claim 14).

  15. The substrate back surface cleaning apparatus according to claim 11, wherein the first rotational speed is controlled to 10 to 120 rpm based on a signal from the control unit, and the second rotational speed is 1000 to 1000. It is preferable to control at 3000 rpm (claim 15). In this case, it is preferable to control the discharge time in the cleaning liquid discharge process to 2 to 5 seconds and to control the swing time in the cleaning liquid swing-off process to 1 second based on a signal from the control unit. .

  The substrate backside cleaning apparatus according to any one of claims 11 to 16, wherein the cleaning liquid discharge step and the cleaning liquid shaking-off step are preferably repeated three times based on a signal from the control unit (claim 17).

  17. The substrate back surface cleaning apparatus according to claim 11, 12, 15 or 16, wherein an angle at which the back surface cleaning nozzle supplies the cleaning liquid to the back surface of the substrate is variably formed, and a signal from the control unit is formed. On the basis of the above, the cleaning liquid discharge step and the cleaning liquid swing-off step are repeated three times, and the discharge angles with respect to the substrate for the first to third times in the cleaning liquid discharge step are 45 °, 30 °, and 90 °. Preferred (claim 18).

  The substrate backside cleaning apparatus according to any one of claims 11 to 18, wherein a portion where the backside cleaning nozzle supplies a cleaning liquid to the backside of the substrate is variably formed along the radial direction of the substrate. (Claim 19).

  In addition, in the substrate back surface cleaning apparatus according to any one of claims 11 to 18, a discharge portion of the cleaning liquid with respect to the back surface of the substrate is variably formed along a radial direction of the substrate, and a signal from the control unit On the basis of the above, the cleaning liquid discharging step and the cleaning liquid shaking-off step are repeated three times, and the first to third cleaning liquid discharge locations in the cleaning liquid discharging step are set to 75 mm, 55 mm, and 5 mm from the outer periphery of the substrate. (Claim 20).

  (1) According to the first, second, fifth, seventh, eleventh, twelfth, fifteenth and seventeenth aspects of the present invention, the cleaning liquid is supplied by rotating at the first rotational speed so as to gently diffuse the cleaning liquid on the back surface of the substrate. The cleaning liquid discharging step and the cleaning liquid sprinkling step of rotating the second substrate at a second speed higher than the first rotational speed and rapidly diffusing and shaking off the cleaning liquid on the back surface of the substrate. In the discharge process, since the rotation speed is low, the processing liquid and the cleaning liquid can easily come into contact with each other, and the processing liquid can be removed by chemical cleaning based on the chemical dissolution reaction of the cleaning liquid itself. The treatment liquid can be removed by the so-called physical washing by the washing treatment by centrifugal force and the washing-off of the washing liquid. Therefore, the treatment liquid adhering to the back surface of the substrate can be removed by repeating the chemical cleaning using the solubility of the cleaning liquid and the physical cleaning using the centrifugal force a plurality of times (for example, three times). In this case, the cleaning region can be widened and the back surface cleaning performance can be further improved by setting the positions where the cleaning liquid is supplied to the back surface of the substrate at a plurality of positions that are different in the radial direction on the inner periphery of the substrate. Claims 2 and 12).

  (2) According to the invention described in claims 3, 4, 8, 13, 14, and 18, the back surface cleaning region is secured by a small number of back surface cleaning nozzles by changing the discharge angle of the cleaning liquid with respect to the back surface of the substrate. be able to. In this case, the variable cleaning process can be performed in multiple stages in the radial direction of the substrate by setting the discharge angle to the substrate for the first to third times in the cleaning liquid discharge process to 45 °, 30 °, and 90 °. (Claims 8 and 18).

  (3) According to the invention described in the ninth, tenth, nineteenth and twentieth aspects, the back surface cleaning region can be formed by a small number of back surface cleaning nozzles by changing the discharge position of the cleaning liquid to the back surface of the substrate along the radial direction of the substrate. Can be secured. In this case, variable cleaning processing is performed in multiple stages in the radial direction of the substrate by setting the first to third cleaning liquid discharge locations in the cleaning liquid discharge step to 75 mm, 55 mm, and 5 mm from the outer periphery of the substrate. (Claims 10 and 20).

  According to this invention, by being configured as described above, it is possible to ensure the back surface cleanability and back surface cleanability for a large-diameter substrate, and to save the back surface cleaning liquid.

1 is a schematic plan view showing an entire processing system in which an exposure apparatus is connected to a coating / development processing apparatus to which a substrate back surface cleaning apparatus according to the present invention is applied. It is a schematic perspective view of the said processing system. It is a schematic longitudinal cross-sectional view of the coating processing apparatus to which the substrate back surface cleaning apparatus according to the first embodiment of the present invention is applied. It is a schematic plan view which shows the board | substrate back surface cleaning apparatus which concerns on the said 1st Embodiment. It is a schematic bottom view which shows the washing | cleaning liquid discharge state of the back surface washing nozzle in this invention. It is a flowchart which shows the process sequence of the substrate back surface cleaning method which concerns on the said 1st Embodiment. It is a schematic bottom view which shows the discharge position of the back surface cleaning nozzle in the board | substrate back surface cleaning apparatus concerning 2nd Embodiment of this invention. It is a schematic side view which shows the cleaning liquid discharge angle in the said 2nd Embodiment. It is a flowchart which shows only the process sequence of the back surface washing | cleaning of 2nd Embodiment. It is a schematic side view which shows the discharge state of the back surface cleaning nozzle in the board | substrate back surface cleaning apparatus which concerns on 3rd Embodiment of this invention. It is a flowchart which shows only the process sequence of the back surface washing | cleaning of 3rd Embodiment. It is a schematic bottom view showing rinse discharge positions of a 300 mm wafer and a 450 mm wafer used for an evaluation test of a back surface cleaning removal rate and a back rinse amount. It is a graph which shows the relationship between the back surface washing removal rate of the result of the said evaluation test, and the amount of back rinses. It is a graph which shows the relationship between a back surface cleaning removal rate and the amount of back rinses when changing the rotation speed of a 300 mm wafer and a 450 mm wafer. It is a graph which shows the back rinse amount which achieves the removal rate 100% when changing the rotation speed of a 300 mm wafer and a 450 mm wafer. It is a schematic bottom view which shows typically the mechanism of the back surface cleaning by the rotation speed of a wafer. It is a graph which shows the relationship between the rotation speed of the wafer at the time of rinse liquid discharge at the time of back surface cleaning processing, and the rinse liquid swinging off, and a cleaning removal rate. It is a graph which compares and shows the amount of back rinses of a 300 mm wafer and a 450 mm wafer.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, a case where the substrate back surface cleaning apparatus according to the present invention is applied to a processing system in which an exposure processing apparatus is connected to a coating / developing processing apparatus will be described.

  The processing system includes a carrier station 1 for carrying in / out a carrier 10 for hermetically storing a plurality of, for example, 25 semiconductor wafers W (hereinafter referred to as wafers W), which are substrates to be processed, and a carrier station 1 for taking out the carrier 10. A processing unit 2 that performs resist coating, development processing, and the like on the wafer W, an exposure unit 4 that performs immersion exposure of the surface of the wafer W in a state where a liquid layer that transmits light is formed on the surface of the wafer W, and the processing unit 2. And an exposure unit 4, and an interface unit 3 that transfers the wafer W.

  The carrier station 1 includes a mounting unit 11 on which a plurality of carriers 10 can be placed side by side, an opening / closing unit 12 provided on a front wall as viewed from the mounting unit 11, and a wafer from the carrier 10 via the opening / closing unit 12. A delivery arm A1 for taking out W is provided.

  Further, a processing unit 2 surrounded by a casing 20 is connected to the back side of the carrier station 1, and the processing unit 2 has a heating / cooling system in order from the left front side when viewed from the carrier station 1. Shelving units U1, U2, and U3 having multiple units are arranged, and liquid processing units U4 and U5 are arranged on the right hand. Between the shelf units U1, U2 and U3, main transfer arms A2 and A3 for transferring the wafer W between the units are provided alternately with the shelf units U1, U2 and U3. Further, the main transfer arms A2 and A3 have one surface portion on the shelf units U1, U2 and U3 side arranged in the front-rear direction as viewed from the carrier station 1, and one surface portion on the right liquid processing unit U4 and U5 side which will be described later. And a space surrounded by a partition wall 21 composed of a rear surface portion forming one surface on the left side. Further, between the carrier station 1 and the processing unit 2 and between the processing unit 2 and the interface unit 3, a temperature / humidity provided with a temperature control device for the processing liquid used in each unit, a duct for temperature / humidity control, and the like. An adjustment unit 22 is arranged.

  The interface unit 3 includes a first transfer chamber 3A and a second transfer chamber 3B which are provided between the processing unit 2 and the exposure unit 4 in the front and rear, respectively, and the first wafer transfer unit A4 and the second transfer chamber 3B, respectively. A second wafer transfer unit A5 is provided.

  The shelf units U1, U2, and U3 are configured such that various units for performing pre-processing and post-processing of the processing performed in the liquid processing units U4 and U5 are stacked in a plurality of stages, for example, 10 stages. A heating unit (HP) for heating (baking) the wafer W, a cooling unit (CPL) for cooling the wafer W, and the like are included. In addition, as shown in FIG. 2, for example, the liquid processing units U4 and U5 include a bottom antireflection film coating unit (BCT) 23 for coating an antireflection film on a chemical solution storage unit such as a resist or a developer, and a coating unit ( COT) 24, a developing unit (DEV) 25 for supplying a developing solution to the wafer W and developing it, and the like are stacked in a plurality of stages, for example, five stages. The substrate back surface cleaning apparatus according to the present invention is provided in a coating unit (COT) 24.

  Next, the flow of the wafer W in the above processing system will be briefly described. First, when the carrier 10 in which the wafer W is stored is placed on the mounting table 11 from the outside, the lid of the carrier 10 is removed together with the opening / closing portion 12, and the wafer W is taken out by the transfer arm A1. Then, the wafer W is transferred to the main transfer arm A2 through a transfer unit that forms one stage of the shelf unit U1, and the antireflection film is pre-processed as a pretreatment of the coating process on one shelf in the shelf units U1 to U3. The temperature of the substrate is adjusted by formation or a cooling unit.

  Thereafter, the wafer W is carried into the coating unit (COT) 24 by the main transfer arm A2, and a resist film is formed on the surface of the wafer W. At this time, the back surface of the wafer W is cleaned by the substrate back surface cleaning apparatus 100 according to the present invention. The wafer W on which the resist film has been formed is unloaded by the main transfer arm A2, loaded into the heating unit, and baked at a predetermined temperature. The wafer W that has been baked is cooled by the cooling unit, and then transferred to the interface unit 3 via the transfer unit of the shelf unit U3, and then transferred into the exposure unit 4 via the interface unit 3. The In the case where a protective film for immersion exposure is applied on the resist film, after cooling by the cooling unit, a chemical solution for protective film is applied in a unit (not shown) in the processing unit 2. . Thereafter, the wafer W is carried into the exposure unit 4 and immersion exposure is performed.

  The wafer W that has been subjected to the immersion exposure is taken out from the exposure unit 4 by the second wafer transfer unit A5 and is carried into a heating unit (PEB) that forms one stage of the shelf unit U6. Thereafter, the wafer W is unloaded from the heating unit (PEB) by the first wafer transfer unit A4 and transferred to the main transfer arm A3. Then, it is carried into the developing unit 25 by the main transport arm A3. In the developing unit 25, the substrate is developed by a substrate back surface cleaning device (not shown) that is also used for development processing, and further cleaning is performed. Thereafter, the wafer W is unloaded from the developing unit 25 by the main transfer arm A3, and returned to the original carrier 10 on the mounting table 11 via the main transfer arm A2 and the transfer arm A1.

<First Embodiment>
An embodiment in which the substrate back surface cleaning apparatus of the present invention is combined with a coating processing apparatus will be described with reference to FIGS.

  As shown in FIGS. 3 and 4, the substrate back surface cleaning apparatus 100 (hereinafter referred to as the back surface cleaning apparatus 100) holds the substrate in the casing 26 by sucking and attracting the center of the back surface of the wafer W in a horizontal position. A spin chuck 30 as a part is provided. The spin chuck 30 is connected to a rotation drive unit 32 such as a servo motor via a shaft portion 31, and is configured to be rotatable while the wafer W is held by the rotation drive unit 32. The rotation drive unit 32 is electrically connected to a controller 80 that is a control unit, and the number of rotations of the spin chuck 30 is controlled based on a control signal from the controller 80. Also, the casing 26 is provided with a loading / unloading port 27 for the wafer W, and a shutter 28 is disposed at the loading / unloading port 27 so as to be opened and closed.

  A cup body 40 having an opening on the upper side is provided so as to surround the side of the wafer W on the spin chuck 30. The cup body 40 includes a cylindrical outer cup 41 and a cylindrical inner cup 42 whose upper side is inclined inward. The outer cup 41 is connected to the lower end of the outer cup 41 by an elevating mechanism 43 such as a cylinder. 41 is moved up and down, and the inner cup 42 is configured to be lifted and lowered by being pushed up by a step formed on the inner peripheral surface of the lower end side of the outer cup 41. The elevating mechanism 43 is electrically connected to the controller 80, and is configured such that the outer cup 41 moves up and down based on a control signal from the controller 80.

  A circular plate 44 is provided on the lower side of the spin chuck 30, and a liquid receiving portion 45 whose cross section is formed in a concave shape is provided around the entire circumference of the circular plate 44. A drain discharge port 46 is formed on the bottom surface of the liquid receiving part 45, and the resist solution and the cleaning liquid that have been spilled from the wafer W or shaken off and stored in the liquid receiving part 45 are passed through the drain discharge port 46. Discharged outside the device. A ring member 47 having a mountain-shaped cross section is provided outside the circular plate 44. Incidentally, for example, three lift pins (not shown) which are substrate support pins penetrating the circular plate 44 are provided, and the wafer W is caused to cooperate by the lift pins and the substrate transfer means (not shown). It is configured to be delivered to the spin chuck 30.

  On the other hand, a processing solution supply nozzle 50 such as a resist solution is provided on the upper side of the wafer W held by the spin chuck 30 so that it can be moved up and down and moved horizontally by the nozzle moving mechanism 200. The processing liquid supply nozzle 50 is connected to a processing liquid supply source 52 via a processing liquid supply pipe 51 provided with a flow rate adjusting valve V1.

  The processing liquid supply nozzle 50 is supported on one end side of a nozzle arm 55 which is a support member, and the other end side of the nozzle arm 55 is connected to a moving base 56 provided with a lifting mechanism (not shown). Further, the moving base 56 can be moved in the lateral direction by a nozzle moving mechanism 200 such as a ball screw mechanism or a timing belt mechanism, for example, along a guide member 57 extending in the X direction on the bottom surface of the casing 26. It is configured. In addition, a standby portion 58 of the processing liquid supply nozzle 50 is provided on one outer side of the cup 40, and the nozzle tip is cleaned in the standby portion 58.

  A back surface cleaning nozzle 60 is provided below the wafer W held by the spin chuck 30. The back surface cleaning nozzle 60 is provided with a cleaning liquid supply source 62 via a cleaning liquid supply pipe 61 having a flow rate adjusting valve V2. It is connected to the. The flow rate and supply time of the cleaning liquid are adjusted by the flow rate adjustment valve V2.

  In this case, the back surface cleaning nozzle 60 discharges the cleaning liquid in a rotation direction and a tangential direction of the wafer W at positions different in the radial direction on the inner periphery of the wafer W, for example, a distance from the outer periphery on the normal line of D1 and D2. (See FIG. 5). For example, when the size of the wafer W is Φ450 mm, the distance D1 from the outer periphery is set to 75 mm, and D2 is set to 55 mm. In FIG. 3, one back surface cleaning nozzle 60 is shown to be omitted to avoid complicated display.

  A nozzle moving mechanism 200 for moving the processing liquid supply nozzle 50, a rotary drive unit 32 for rotating the spin chuck 30, an elevating mechanism 43 for the cup 40, and flow rate adjusting valves V1 and V2 for adjusting the flow rates of the processing liquid and the cleaning liquid are: The control unit 80 is electrically connected to the controller 80, and is configured to output a control signal to each of the units based on a program stored in a computer built in the controller 80, for example.

  Next, the operation | movement aspect of the board | substrate back surface cleaning apparatus 100 comprised as mentioned above is demonstrated. Initially, when the wafer W is not carried into the substrate back surface cleaning apparatus 100, the outer cup 41 and the inner cup 42 are in the lowered position, and the processing liquid supply nozzle 50 and the solvent supply nozzle 60 are on standby at a predetermined standby position. doing. In the above processing system, when the wafer W is loaded into the substrate back surface cleaning apparatus 100 by the main transfer arm A3 (see FIG. 1), the wafer W is turned into the spin chuck 30 by the cooperative action of the main transfer arm A3 and a lift pin (not shown). Is passed on.

  Thereafter, the outer cup 41 and the inner cup 42 are set to the raised position, and the resist liquid is supplied onto the wafer W from the processing liquid supply nozzle 50, and the spin chuck 30 rotates to remove the resist liquid by a known spin coating method. Supply (application) is performed. In this embodiment, for example, the wafer W is rotated at a rotational speed of 1000 rpm for 1 second (sec), and a resist solution is supplied (discharged) from the processing solution supply nozzle 50 to the center of the wafer W. Then, the resist solution spreads outward along the surface of the wafer W by the centrifugal force generated by the rotation of the wafer W, and a thin liquid film is formed.

  Immediately after the processing liquid supply nozzle 50 stops supplying the resist liquid, the cleaning liquid is quickly discharged from the back surface cleaning nozzle 60 to clean the back surface of the wafer W. Hereinafter, this cleaning process will be described in detail with reference to FIGS.

  First, the wafer W is carried into the substrate back surface cleaning apparatus 100 by the main transfer arm A3 (see FIG. 1), and the wafer W is held by the spin chuck 30 (step S1). Thereafter, the processing liquid supply nozzle 50 moves to the upper central portion of the wafer W, the resist liquid is supplied from the processing liquid supply nozzle 50 to the wafer W, and the wafer W is rotated (rotation speed: 1000 rpm, time: 1 sec). Then, a resist coating process is performed {step S2}.

  After applying the resist, the wafer W is rotated at a low first rotation speed (120 rpm), and the rotation direction and tangent of the wafer W are positioned on the normal lines of 75 mm and 55 mm from the outer periphery of the back surface of the wafer W from the back surface cleaning nozzle 60. The cleaning liquid is discharged in the direction for 3 seconds, and the cleaning liquid is gently diffused inwardly around the back surface of the wafer W {cleaning liquid discharge (1); step S3}. As a result, the resist solution and the cleaning solution are easily brought into contact with each other, and the resist solution is removed by so-called chemical cleaning by a chemical dissolution reaction of the cleaning solution itself.

  Thereafter, the discharge of the cleaning liquid is stopped, the wafer W is rotated at a high-speed second rotation speed (1000 rpm) for 1 sec, and the cleaning liquid on the back surface of the wafer W is rapidly diffused and shaken {cleaning liquid swing-off (1). Step S4}. As a result, the resist solution is removed by so-called physical cleaning by the cleaning process by centrifugal force accompanying the high-speed rotation of the wafer W and the cleaning liquid swing-off.

  Next, the wafer W is rotated again at a low first rotation speed (120 rpm), and the wafer W is moved from the back surface cleaning nozzle 60 to the normal positions of 75 mm and 55 mm from the outer periphery of the back surface of the wafer W as described above. The cleaning liquid is discharged in the rotation direction and the tangential direction for 3 seconds, and the cleaning liquid is gently diffused inwardly around the back surface of the wafer W {cleaning liquid discharge (2); Step S5}.

  Thereafter, the discharge of the cleaning liquid is stopped again, and the wafer W is rotated at a high-speed second rotation speed (1000 rpm) for 1 sec, and the cleaning liquid on the back surface of the wafer W is rapidly diffused and shaken off {cleaning liquid shaking off (2 Step S6}.

  Thereafter, the wafer W is rotated again at the first low rotational speed (120 rpm), and the wafer W is rotated from the back surface cleaning nozzle 60 to the positions on the normal lines of 75 mm and 55 mm from the outer periphery of the back surface of the wafer W in the same manner as described above. The cleaning liquid is discharged in the direction and tangential direction for 3 seconds, and the cleaning liquid is gently diffused inwardly around the back surface of the wafer W {cleaning liquid discharge (3); step S7}.

  Thereafter, the discharge of the cleaning liquid is stopped again, and the wafer W is rotated at a high-speed second rotation speed (1000 rpm) for 1 sec, and the cleaning liquid on the back surface of the wafer W is rapidly diffused and shaken off {cleaning liquid shaking off (3 Step S8}.

  As described above, the wafer W is rotated at a low first rotation speed (120 rpm), and the rotation direction of the wafer W is set to positions on the normal lines of 75 mm and 55 mm from the outer periphery of the back surface of the wafer W from the back surface cleaning nozzle 60. In addition, the cleaning liquid is discharged in the tangential direction for 3 seconds, and the cleaning liquid discharging step for gently diffusing the cleaning liquid in the inner periphery of the back surface of the wafer W is stopped, and the discharge of the cleaning liquid is stopped, and the wafer W is moved at a second high speed (1000 rpm). ), The cleaning liquid on the back surface of the wafer W is rapidly diffused, and the cleaning liquid shaking-off process is repeated three times.

  Thereafter, the wafer W is rotated at high speed for 10 sec (rotation speed: 1000 rpm) to remove the cleaning liquid remaining on the back surface of the wafer W {spin drying; step S9}.

  Thereafter, the wafer W is unloaded from the substrate back surface cleaning apparatus 100, and the process ends.

  According to the back surface cleaning method of the first embodiment, the cleaning liquid discharge step of supplying the cleaning liquid by rotating at the first rotation speed (120 rpm) to gently diffuse the cleaning liquid on the back surface of the wafer, and the speed higher than the first rotation speed The cleaning liquid discharging step is performed at a low speed in the cleaning liquid discharge step by alternately repeating the cleaning liquid sprinkling step of rotating the second rotation speed (1000 rpm) and rapidly diffusing and shaking off the cleaning liquid on the back surface of the wafer. The treatment liquid and the cleaning liquid can be easily brought into contact with each other, and the resist liquid can be removed by chemical cleaning based on the chemical dissolution reaction of the cleaning liquid itself. In the cleaning liquid swing-off process, the cleaning process and the cleaning liquid swing-off are performed by the centrifugal force accompanying the high-speed rotation. In other words, the resist solution can be removed by physical cleaning. Therefore, the resist solution adhering to the back surface of the wafer can be removed by repeating the chemical cleaning using the solubility of the cleaning solution and the physical cleaning using the centrifugal force three times. In this case, the position where the cleaning liquid is supplied to the back surface of the wafer W is set to be different positions of 75 mm and 55 mm from the outer periphery in the radial direction inside the periphery of the substrate. Improvements can be made.

  In addition, it is preferable that the 1st rotation speed is the range of 10-120 rpm, and it is preferable that the 2nd rotation speed is the range of 1000-3000 rpm.

Second Embodiment
In the first embodiment, the case where the discharge angle of the cleaning liquid of the back surface cleaning nozzle 60 is fixed is described. However, as in the second embodiment shown in FIG. 8, the discharge angle of the cleaning liquid of the back surface cleaning nozzle 60 is variable. It is good.

  In this case, the back surface cleaning nozzle 60 is disposed at a lower position away from the back surface of the wafer W by H (for example, 10 mm), and the discharge angle of the cleaning liquid is adjusted by an angle adjustment mechanism (not shown) using a stepping motor, for example. With respect to the back surface of the wafer W, it can be changed to 30 °, 45 ° and 90 °, that is, the angle can be adjusted. The angle adjustment mechanism is electrically connected to the controller 80, and the discharge angle is adjusted based on a control signal from the controller 80.

  With this configuration, as shown in FIGS. 7 and 8, the discharge angle of the back surface cleaning nozzle 60 is set to 90 °, and the outer periphery of the back surface of the wafer W is positioned at a position D3 (for example, a position of 5 mm). The cleaning liquid can be discharged, whereby the bevel portion of the wafer W can be cleaned. Further, when the discharge angle of the back surface cleaning nozzle 60 is changed from 90 ° to 45 °, as shown in FIG. 8, the cleaning liquid is discharged at a distance L1 (10 mm) away from the discharge position when the discharge angle is 90 °. It is possible to reduce the rebound of the cleaning liquid. In this state, for example, the cleaning liquid can be discharged from the outer periphery of the wafer W to a position D5 (for example, a position of 75 mm) to perform the back surface cleaning of the region of the outer peripheral portion 75 mm on the wafer back surface side. Further, when the discharge angle of the back surface cleaning nozzle 60 is changed from 90 ° to 30 °, as shown in FIG. 8, the cleaning liquid is discharged at a position L2 distance (17 mm) away from the discharge position when the discharge angle is 90 °. Compared with the case where the discharge angle is 45 °, the trajectory drawn by the cleaning liquid can be lengthened and the splashing of the cleaning liquid can be further reduced. Further, since the incident angle of the cleaning liquid with respect to the back surface of the wafer W becomes gentle, the cleaning liquid easily spreads on the back surface of the wafer W. In this state, for example, the cleaning liquid is discharged to the position of D6 (for example, about 75 mm) slightly outside the position of D5 from the outer periphery of the wafer W to perform the back surface cleaning of the area of the outer peripheral portion of about 75 mm on the wafer back surface side. be able to.

  In the second embodiment, the other parts are the same as those in the first embodiment, and thus the same parts are designated by the same complements and the description thereof is omitted.

  Next, the back surface cleaning process of 2nd Embodiment is demonstrated with reference to FIG. FIG. 9 shows only the back surface cleaning process. Here, the cleaning liquid discharge rate of the back surface cleaning nozzle 60 is 50 ml / min. Is set to

  Similarly to the first embodiment, after performing the resist coating process, the wafer W is rotated at the first low speed (120 rpm) at a low speed, and the wafer W is removed from the back surface cleaning nozzle 60 whose discharge angle is adjusted to 45 °. The cleaning liquid is discharged for 3 seconds in the rotational direction and tangential direction of the wafer W at a position on the normal line of 75 mm from the outer periphery of the back surface, and the cleaning liquid is gently diffused inwardly around the back surface of the wafer W {cleaning liquid discharge (1); Step S2-1}. As a result, the resist solution in the region of 75 mm from the outer periphery on the back side of the wafer easily comes into contact with the cleaning solution, and the resist solution is removed by chemical cleaning by chemical dissolution reaction of the cleaning solution itself.

  Thereafter, the discharge of the cleaning liquid is stopped, the wafer W is rotated at a high-speed second rotation speed (1000 rpm) for 1 sec, and the cleaning liquid on the back surface of the wafer W is rapidly diffused and shaken {cleaning liquid swing-off (1). Step S2-2}. As a result, the resist solution is removed by so-called physical cleaning by the cleaning process by centrifugal force accompanying the high-speed rotation of the wafer W and the cleaning liquid swing-off.

  Next, the discharge angle of the back surface cleaning nozzle 60 is adjusted to 30 °, and the wafer W is rotated again at the first low rotation speed (120 rpm). The cleaning liquid is discharged for 3 seconds in the rotation direction and tangential direction of the wafer W at a position on the normal line of about 75 mm from the outer periphery, and the cleaning liquid is gently diffused inwardly around the back surface of the wafer W {cleaning liquid discharge (2); step S2-3}. As a result, the incident angle of the cleaning liquid with respect to the back surface of the wafer W becomes gentler than that of the cleaning liquid discharge (1) (S2-1), so that the cleaning liquid easily spreads on the back surface of the wafer W. In other words, the resist solution is removed by chemical cleaning.

  Thereafter, the discharge of the cleaning liquid is stopped again, and the wafer W is rotated at a high-speed second rotation speed (1000 rpm) for 1 sec, and the cleaning liquid on the back surface of the wafer W is rapidly diffused and shaken off {cleaning liquid shaking off (2 ); Step S2-4}.

  Thereafter, the discharge angle of the back surface cleaning nozzle 60 is adjusted to 90 °, the wafer W is rotated again at the first low speed (120 rpm), and the inner periphery of the periphery of the back surface of the wafer W from the back surface cleaning nozzle 60. The cleaning liquid is discharged for 3 seconds to a position 5 mm from the wafer to clean the bevel portion of the wafer W {cleaning liquid discharge (3); step S2-5}.

  Thereafter, the discharge of the cleaning liquid is stopped again, and the wafer W is rotated at a high-speed second rotation speed (1000 rpm) for 1 sec, and the cleaning liquid on the back surface of the wafer W is rapidly diffused and shaken off {cleaning liquid shaking off (3 ); Step S2-6}.

  Thereafter, the wafer W is rotated at a high speed (rotation speed: 1000 rpm) for 10 seconds to remove the cleaning liquid remaining on the back surface of the wafer W, and then the wafer W is unloaded from the substrate back surface cleaning apparatus 100 and the processing is completed. .

  According to the back surface cleaning method of the second embodiment, by changing the discharge angle of the cleaning liquid with respect to the back surface of the wafer W, a wide range of back surface cleaning regions can be secured by a small number of back surface cleaning nozzles 60. In this case, the variable cleaning process can be performed in multiple stages with respect to the radial direction of the substrate by setting the discharge angles of the first to third wafers W in the cleaning liquid discharge process to 45 °, 30 °, and 90 °. it can.

  In the above embodiment, the back surface cleaning nozzle 60 is variable, but the back surface of the wafer W is changed by changing the discharge angle at every position of the cleaning liquid supply position on the back surface of the wafer W, for example, 75 mm, 55 mm, and 5 mm from the outer periphery of the back surface of the wafer W. A cleaning nozzle 60 may be arranged.

<Third Embodiment>
FIG. 10 is a schematic side view showing a discharge state of the back surface cleaning nozzle 60 in the back surface cleaning apparatus according to the third embodiment of the present invention.

  As shown in FIG. 10, the back surface cleaning nozzle 60 in the third embodiment is disposed at a position below the wafer W held by the spin chuck 30, and the nozzle moving mechanism 63 moves the cleaning liquid discharge location in the radial direction of the wafer W. It is variably formed.

  The nozzle moving mechanism 63 is formed by, for example, a ball screw mechanism, a timing belt mechanism, or the like, and connects the movable table 65 on which the back surface cleaning nozzle 60 is placed to the reciprocating unit 64 of the nozzle moving mechanism 63, thereby The liquid discharge location of the cleaning nozzle 60 can be varied in the radial direction of the wafer W. The nozzle moving mechanism 63 is electrically connected to the controller 80, and the liquid discharge location of the back surface cleaning nozzle 60 can be varied in the radial direction of the wafer W based on a control signal from the controller 80.

  In this case, the back surface cleaning nozzle 60 is moved to an arbitrary position within the range of the position (D5) 75 mm from the outer periphery of the wafer W and the position (D3) 5 mm from the outer periphery by the nozzle moving mechanism 63, for example, the position (D5) 75 mm from the outer periphery. The position can be changed to any position, such as a position (D4) 55 mm from the outer periphery, a position (D7) 35 mm from the outer periphery, and a position (D3) 5 mm from the outer periphery.

  In addition, in 3rd Embodiment, since another part is the same as 1st Embodiment, description is abbreviate | omitted.

  Next, the back surface cleaning process of 3rd Embodiment is demonstrated with reference to FIG. FIG. 11 shows only the back surface cleaning process. Here, the cleaning liquid discharge rate of the back surface cleaning nozzle 60 is 50 ml / min. A case where the discharge angle is formed to be adjustable to 45 ° and 90 ° will be described.

  Similarly to the first embodiment, after performing the resist coating process, the wafer W is rotated at the first low speed (120 rpm) at a low speed, and the wafer W is removed from the back surface cleaning nozzle 60 whose discharge angle is adjusted to 45 °. The cleaning liquid is discharged for 3 seconds in the rotational direction and tangential direction of the wafer W at a position on the normal line of 75 mm from the outer periphery of the back surface, and the cleaning liquid is gently diffused inwardly around the back surface of the wafer W {cleaning liquid discharge (1); Step S3-1}. As a result, the resist solution in the region of 75 mm from the outer periphery on the back side of the wafer easily comes into contact with the cleaning solution, and the resist solution is removed by chemical cleaning by chemical dissolution reaction of the cleaning solution itself.

  Thereafter, the discharge of the cleaning liquid is stopped, the wafer W is rotated at a high-speed second rotation speed (1000 rpm) for 1 sec, and the cleaning liquid on the back surface of the wafer W is rapidly diffused and shaken {cleaning liquid swing-off (1). Step S3-2}. As a result, the resist solution is removed by so-called physical cleaning by the cleaning process by centrifugal force accompanying the high-speed rotation of the wafer W and the cleaning liquid swing-off.

  Next, in a state where the discharge angle of the back surface cleaning nozzle 60 is 45 °, the wafer W is rotated again at the first low rotation speed (120 rpm), and the outer periphery of the back surface of the wafer W is returned from the back surface cleaning nozzle 60 in the same manner as described above. The cleaning liquid is discharged for 3 seconds in the rotational direction and tangential direction of the wafer W at a position on the normal line of 55 mm from the surface of the wafer W, and the cleaning liquid is gently diffused inwardly around the back surface of the wafer W {cleaning liquid discharge (2); step S3- 3}. As a result, the resist solution in the region of 55 mm from the outer periphery on the back side of the wafer easily comes into contact with the cleaning solution, and the resist solution is removed by chemical cleaning by chemical dissolution reaction of the cleaning solution itself.

  Thereafter, the discharge of the cleaning liquid is stopped again, and the wafer W is rotated at a high-speed second rotation speed (1000 rpm) for 1 sec, and the cleaning liquid on the back surface of the wafer W is rapidly diffused and shaken off {cleaning liquid shaking off (2 ); Step S3-4}.

  Thereafter, the discharge angle of the back surface cleaning nozzle 60 is adjusted to 90 °, the wafer W is rotated again at the first low speed (120 rpm), and the inner periphery of the periphery of the back surface of the wafer W from the back surface cleaning nozzle 60. The cleaning liquid is discharged for 3 seconds to a position 5 mm from the wafer to clean the bevel portion of the wafer W {cleaning liquid discharge (3); Step S3-5}.

  Thereafter, the discharge of the cleaning liquid is stopped again, and the wafer W is rotated at a high-speed second rotation speed (1000 rpm) for 1 sec, and the cleaning liquid on the back surface of the wafer W is rapidly diffused and shaken off {cleaning liquid shaking off (3 ; Step S3-6}.

  Thereafter, the wafer W is rotated at a high speed (rotation speed: 1000 rpm) for 10 seconds to remove the cleaning liquid remaining on the back surface of the wafer W, and then the wafer W is unloaded from the substrate back surface cleaning apparatus 100 and the processing is completed. .

  According to the back surface cleaning method of the third embodiment, a wide range of back surface cleaning regions are secured by a small number of back surface cleaning nozzles 60 by making the discharge position of the cleaning liquid on the back surface of the wafer W variable along the radial direction of the wafer W. be able to. In this case, variable cleaning processing is performed in multiple stages in the radial direction of the wafer W by setting the first to third cleaning liquid discharge locations in the cleaning liquid discharge step to 75 mm, 55 mm, and 5 mm from the outer periphery of the wafer W. It can be carried out.

<Other embodiments>
In the first embodiment, the case where two fixed back surface cleaning nozzles 60 are provided has been described. However, the number of the fixed back surface cleaning nozzles 60 is not limited to this, for example, as shown in FIG. Three backside cleanings that discharge cleaning liquid in the rotational direction and tangential direction of the wafer W at a position 75D from the outer periphery of the wafer W (D5), a position 55D from the outer periphery (D4), and a position 35D from the outer periphery (D7). A nozzle 60 may be used. Alternatively, four backside cleaning nozzles 60 that discharge the cleaning liquid to the opposing positions (positions of 180 degrees) of the position (D5) 75 mm from the outer periphery of the wafer W and the position (D4) 55 mm from the outer periphery may be used. Good.

  In the above embodiment, the discharge direction of the back surface cleaning nozzle 60 is a tangential direction, but may be a normal direction of the back surface outer periphery of the wafer W.

  In the above embodiment, the rotation speed when discharging the cleaning liquid onto the back surface of the wafer W is low (for example, 120 rpm), and the rotation speed when discharging of the cleaning liquid is stopped is high (for example, 1000 rpm). . However, instead of discharging the cleaning liquid, stopping the discharge of the cleaning liquid and stopping the discharging even if the rotation speed when discharging the cleaning liquid is high (for example, 1000 rpm) and the rotation speed when discharging the cleaning liquid is low (for example, 120 rpm). Compared with the prior art in which intermittent cleaning is not repeated, the chemical consumption can be reduced.

  In the first embodiment, the case where the discharge angle of the fixed back surface cleaning nozzle 60 is fixed has been described. However, the discharge angle of the back surface cleaning nozzle 60 may be changed according to the discharge position.

  Moreover, although the case where the back surface cleaning apparatus according to the present invention is applied to the resist coating process has been described in the above embodiment, the present invention is not limited to this, and the process is performed on the surface of the substrate rotating around the vertical axis. The present invention can also be applied to substrate processing to which a liquid is supplied, for example, development processing.

Hereinafter, an evaluation experiment performed to complete the present invention will be described.
(Evaluation Experiment 1)
Evaluation conditions: Resist: A positive photoresist corresponding to an ArF immersion process is applied to the surface of the bare wafer. Cleaning liquid (back rinse liquid): cyclohexanone Discharge flow rate: 100 ml / min
・ Nozzle: Tangent direction (2)
・ Discharge position: 70mm from wafer periphery
Under the above evaluation conditions, the back surface cleaning removal rate and the back rinse amount when the Φ300 mm wafer WA shown in FIG. As a result of the examination, results as shown in FIG. 13 were obtained.

  As a result of the evaluation experiment 1, it has been found that the rinsing amount of about 3.4 times is necessary for the cleaning method of Φ450 mm wafer whose area ratio is 1.8 times that of the existing Φ300 mm wafer cleaning method.

(Evaluation Experiment 2)
Next, among the above evaluation conditions, the discharge position on the Φ450 mm wafer is set to 75 mm from the outer periphery of the wafer W (Φ300 mm wafer is 70 mm from the outer periphery). When the relationship between the resist removal rate and the amount of back rinse was examined while changing to 120 rpm, 500 rpm, 1000 rpm, and 2000 rpm, the results shown in FIGS. 14 and 15 were obtained.

  As a result of the above evaluation experiment 2, in the case of a Φ450 mm wafer, when the speed is 120 rpm, the amount of back rinse of the existing Φ300 mm wafer cleaning method is 23.3 ml (3 repetitions) and 33.3 ml (4 repetitions), Then, it was 2000 rpm (repeated 5 times), 1000 rpm (repeated 7 times), and 500 rpm (repeated 10 times).

  Considering the mechanism of the back surface cleaning from Evaluation Experiment 2, at a low speed of 120 rpm, as shown in FIG. 16A, the resist film spreads from the back rinse position D0 as a starting point, while the back rinse liquid L spreads with a relatively large particle size. Then, the resist is removed by the chemical dissolution action of the rinse solution itself. In FIG. 16A, the pitch Pa between the resist residue and the removal region was 10 to 15 mm.

  On the other hand, at a high speed of 1000 rpm, as shown in FIG. 16B, the resist film is radiated at an acute angle by the back rinse liquid L being subdivided and discharged starting from the back rinse position D0. Removed. This is presumed to be governed by the physical cleaning action by the high-speed rotation process. In FIG. 16B, the resist residue and the pitch Pb between the removal regions were 2 to 3 mm.

(Evaluation Experiment 3)
Focusing on the chemical dissolution effect at a low speed of 120 rpm and the physical cleaning action at a high speed of 1000 rpm from the results of the evaluation experiment 2, the back rinse (rinsing liquid discharge) at 120 rpm and the back rinse at 1000 rpm are repeatedly stopped. In order to examine the effect of intermittent discharge, the procedure of the cleaning process as shown in Table 1, that is, the cleaning liquid discharging process for performing the back rinse at 120 rpm for 5 seconds, and the cleaning liquid swing-off process for stopping the back rinse at 1000 rpm for 1 second. The evaluation experiment 3 was conducted by repeating the above procedure three times. Note that the back rinse discharge position at this time was set at a position 75 mm from the outer periphery.

  As a result of Evaluation Experiment 3, the backside cleaning removal rate was 100%.

(Evaluation Experiment 4)
Since the intermittent discharge time is 15 seconds in the evaluation experiment 3, in order to try to shorten the intermittent discharge time, the cleaning liquid discharge time in the cleaning process of the evaluation experiment 3 is changed from 5 seconds to 3 seconds, and the cleaning process as shown in Table 2 is performed. The evaluation experiment 4 was performed by the above procedure, that is, the cleaning liquid discharging process in which the back rinse at 120 rpm is performed for 3 seconds and the cleaning liquid shaking process in which the back rinse at 1000 rpm is stopped for 1 second are repeated three times.

  As a result of Evaluation Experiment 4, the backside cleaning removal rate could not be achieved 100%, and a resist residue was generated in a striped pattern from the center of the cleaning region to the outer periphery.

(Evaluation Experiment 5)
Next, the back rinse discharge position is set to a position 75 mm from the outer periphery and a position 55 mm from the outer periphery, and the procedure of the cleaning process as shown in Table 3, that is, the cleaning liquid discharge process for performing the back rinse at 120 rpm for 3 seconds. Then, the evaluation experiment 5 was performed by the procedure of repeatedly performing the washing liquid swing-off process of stopping the back rinse at 1000 rpm for 1 second three times.

  As a result of Evaluation Experiment 5, the backside cleaning removal rate was 100%. The intermittent discharge time at this time was 9 seconds, which was shortened by 6 seconds compared to the intermittent discharge time of 15 seconds in Evaluation Experiment 3 in which the back rinse discharge position was 75 mm from the outer periphery.

(Evaluation Experiment 6)
Next, in order to investigate the relationship between the time of the cleaning liquid discharge process and the number of rotations, an evaluation experiment 6 was performed according to the procedure shown in Table 4 with the back rinse discharge position set to the same setting as in evaluation experiment 5. In addition, it experimented by setting the value of time (T) as 3 sec, 2 sec, and 1 sec, respectively.

As a result of the evaluation experiment 6, as shown in Table 5, the backside cleaning removal rate was 100% at the discharge time of 3 sec and 2 sec with respect to the rotation speed of 120 rpm. There wasn't.

(Evaluation Experiment 7)
Next, in order to investigate the relationship between the time and the rotational speed in the cleaning liquid discharge process and the cleaning liquid swing-off process, as shown in Table 6, the rotational speed (R1) in the cleaning liquid discharge process (back rinse discharge) and the cleaning liquid swing-off process When the evaluation experiment 7 was performed while changing the number of rotations (R2), results as shown in FIG. 17 were obtained.

  As a result of the evaluation experiment 7, the back surface cleaning removal rate was able to achieve 100% in the range of the rotation speed (R1) at the time of back rinse discharge of 10 to 120 rpm and the rotation speed (R2) at the time of the washing liquid shaking process of 1000 to 3000 rpm. .

(Evaluation Experiment 8)
Next, with regard to the back surface cleaning method of the second embodiment, the cleaning process procedure as shown in Table 3 above, that is, the cleaning liquid discharge step (3) for performing back rinse at 120 rpm for 3 seconds {Discharge position: 75 mm, discharge angle : 45 °}, cleaning liquid discharge step (2) {discharge position: 75 mm, discharge angle: 30 °}, cleaning liquid discharge step (3) {discharge position: 5 mm, discharge angle: 90 °} and back rinse at 1000 rpm Evaluation experiment 8 was performed by a procedure of repeatedly performing the washing liquid shaking-off process of stopping for 1 second three times. As a result of the evaluation experiment 8, the backside cleaning removal rate was 100%.

(Evaluation Experiment 9)
Next, regarding the back surface cleaning method of the third embodiment, the cleaning process procedure as shown in Table 3 above, that is, the cleaning liquid discharge process (1) for performing the back rinse at 120 rpm for 3 seconds {Discharge position: 75 mm, discharge angle : 45 °}, cleaning liquid discharge step (2) {discharge position: 55 mm, discharge angle: 45 °}, cleaning liquid discharge step (3) {discharge position: 5 mm, discharge angle: 90 °} and back rinse at 1000 rpm The evaluation experiment 9 was performed by the procedure of repeating the washing liquid shaking-off process of stopping for 1 sec three times. As a result of the evaluation experiment 9, the back surface cleaning removal rate was 100%.

  From the results of the above evaluation experiment, as shown in FIG. 18, the discharge position is set to 75 mm from the outer periphery in the large-diameter Φ450 mm wafer, whereas the back rinse amount of the existing Φ300 mm wafer cleaning method is 25.0 ml. In this case, the back rinse amount was 25.0 ml, the same amount as that of the existing Φ300 mm wafer. Further, when the discharge position was set at a position 75 mm from the outer periphery and 55 mm from the outer periphery, the back rinse amount was as small as 10.0 ml.

30 Spin chuck (substrate holder)
32 Rotation drive unit 50 Treatment liquid supply nozzle 60 Back surface cleaning nozzle 63 Nozzle moving mechanism 80 Controller (control unit)
V2 Flow control valve

Claims (20)

After the step of supplying the processing liquid to the surface of the substrate that rotates about the vertical axis, the cleaning step of supplying the cleaning liquid to a plurality of positions in the inner periphery of the back surface of the substrate while the substrate is rotated. Comprising
The cleaning process includes a cleaning liquid discharge process for supplying the cleaning liquid by rotating at a first rotational speed so as to gently diffuse the cleaning liquid on the back surface of the substrate, and a second rotational speed higher than the first rotational speed. A substrate back surface cleaning method, wherein the cleaning liquid sprinkling step of rotating and rapidly diffusing and sprinkling the cleaning liquid on the back surface of the substrate is alternately repeated a plurality of times. In the substrate back surface cleaning method according to claim 1,
The substrate back surface cleaning method, wherein the positions for supplying the cleaning liquid to the back surface of the substrate are a plurality of positions which are different in the radial direction in the inner periphery of the substrate. In the substrate back surface cleaning method according to claim 1 or 2,
A substrate back surface cleaning method, wherein a discharge angle of the cleaning liquid with respect to the back surface of the substrate is variable. In the substrate back surface cleaning method according to claim 1 or 2,
A substrate back surface cleaning method, wherein a discharge angle of the cleaning liquid with respect to the back surface of the substrate is different for each position at which the cleaning liquid is supplied to the back surface of the substrate. In the substrate back surface cleaning method according to any one of claims 1 to 4,
The substrate back surface cleaning method, wherein the first rotation speed is 10 to 120 rpm, and the second rotation speed is 1000 to 3000 rpm. In the substrate back surface cleaning method according to any one of claims 1 to 5,
A substrate back surface cleaning method, wherein a discharge time in the cleaning liquid discharge step is 2 to 5 seconds, and a swing-off time in the cleaning liquid swing-off step is 1 second. In the substrate back surface cleaning method according to any one of claims 1 to 6,
The substrate back surface cleaning method, wherein the cleaning liquid discharging step and the cleaning liquid shaking-off step are repeated three times. In the substrate back surface cleaning method according to claim 1, 2, 5, or 6,
While changing the discharge angle of the cleaning liquid with respect to the back surface of the substrate, the cleaning liquid discharging step and the cleaning liquid swing-off step are repeated three times, and the discharge angle with respect to the substrate for the first to third times in the cleaning liquid discharging step is set as follows: A substrate back surface cleaning method, characterized by being 45 °, 30 °, and 90 °. In the substrate back surface cleaning method according to any one of claims 1 to 8,
A substrate back surface cleaning method, wherein a discharge portion of the cleaning liquid to the back surface of the substrate is variable along a radial direction of the substrate. In the substrate back surface cleaning method according to any one of claims 1 to 8,
The discharge position of the cleaning liquid with respect to the back surface of the substrate is made variable along the radial direction of the substrate, and the cleaning liquid discharging process and the cleaning liquid shaking process are repeated three times, and the first to third times in the cleaning liquid discharging process. A substrate back surface cleaning method, characterized in that the discharge position of the cleaning liquid is 75 mm, 55 mm, 5 mm from the outer periphery of the substrate. A substrate holding unit that rotatably holds the substrate around a vertical axis;
A rotation driving unit that rotates the substrate holding unit;
A processing liquid supply nozzle for supplying a processing liquid to the surface of the substrate held by the substrate holding unit;
A back surface cleaning nozzle for supplying a cleaning liquid to a plurality of positions in the inner periphery of the back surface of the substrate rotated by the substrate holding unit;
A control unit for controlling the rotation of the rotation driving unit and the driving of the back surface cleaning nozzle,
Based on a signal from the control unit, a cleaning liquid discharging step of supplying the cleaning liquid by rotating at a first rotational speed so as to gently diffuse the cleaning liquid on the back surface of the substrate, and a first speed higher than the first rotational speed. A substrate back surface cleaning apparatus, wherein the cleaning liquid sprinkling step of rotating and rotating at a rotational speed of 2 to rapidly diffuse and shake off the cleaning liquid on the back surface of the substrate is repeated a plurality of times alternately. The substrate back surface cleaning apparatus according to claim 11,
A substrate back surface cleaning apparatus, wherein a plurality of the back surface cleaning nozzles are provided, and each back surface cleaning nozzle supplies a cleaning liquid to a plurality of radially different positions on the inner periphery of the substrate. In the substrate back surface cleaning apparatus according to claim 11 or 12,
The substrate back surface cleaning apparatus, wherein an angle at which the back surface cleaning nozzle supplies the cleaning liquid to the back surface of the substrate is variably formed. In the substrate back surface cleaning apparatus according to claim 11 or 12,
The substrate back surface cleaning apparatus, wherein the back surface cleaning nozzle is formed so that a discharge angle of the cleaning liquid with respect to the back surface of the substrate is different at each position where the cleaning liquid is supplied to the back surface of the substrate. The substrate back surface cleaning apparatus according to any one of claims 11 to 14,
The substrate back surface cleaning apparatus, wherein the first rotation speed is controlled to 10 to 120 rpm and the second rotation speed is controlled to 1000 to 3000 rpm based on a signal from the control unit. The substrate back surface cleaning apparatus according to any one of claims 11 to 15,
The substrate back surface cleaning apparatus, wherein a discharge time in the cleaning liquid discharge process is controlled to 2 to 5 seconds based on a signal from the control unit, and a swing time in the cleaning liquid swing-off process is controlled to 1 second. . The substrate back surface cleaning apparatus according to any one of claims 11 to 16,
The substrate back surface cleaning apparatus, wherein the cleaning liquid discharge step and the cleaning liquid shaking-off step are repeated three times based on a signal from the control unit. In the substrate back surface cleaning apparatus according to claim 11, 12, 15 or 16,
The angle at which the back surface cleaning nozzle supplies the cleaning liquid to the back surface of the substrate is variably formed, and based on the signal from the control unit, the cleaning liquid discharging step and the cleaning liquid shaking step are repeated three times. A substrate back surface cleaning apparatus, characterized in that discharge angles with respect to the substrate for the first to third times in the cleaning liquid discharging step are 45 °, 30 °, and 90 °. The substrate back surface cleaning apparatus according to any one of claims 11 to 18,
The substrate back surface cleaning apparatus, wherein a portion where the back surface cleaning nozzle supplies a cleaning liquid to the back surface of the substrate is variably formed along a radial direction of the substrate. The substrate back surface cleaning apparatus according to any one of claims 11 to 18,
The cleaning liquid discharge location on the back surface of the substrate is variably formed along the radial direction of the substrate, and the cleaning liquid discharging step and the cleaning liquid shaking step are repeated three times based on a signal from the control unit. A substrate back surface cleaning apparatus, wherein the first to third cleaning liquid discharge locations in the cleaning liquid discharge step are set to 75 mm, 55 mm, and 5 mm from the outer periphery of the substrate.

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