JP5941023B2 - Substrate cleaning apparatus, substrate cleaning method, and computer-readable recording medium - Google Patents

Description

  The present invention relates to a substrate cleaning apparatus, a substrate cleaning method, and a computer-readable recording medium.

  Currently, in performing microfabrication, it is widely performed to form a concavo-convex pattern (for example, a resist pattern) on a substrate (for example, a semiconductor wafer) using a photolithography technique. Specifically, a concavo-convex pattern is formed by an application process of applying a resist material on a substrate to form a resist film, an exposure process of exposing the resist film, and a developing process of developing the exposed resist film. .

  The development step includes a cleaning process in which the resist dissolved in the developer is removed from the substrate surface with the developer along with the developer. In this cleaning process, if the resist melt is not sufficiently removed and remains on the substrate, a desired uneven pattern cannot be obtained and development defects may occur.

  Therefore, in order to suppress such development defects, the substrate cleaning methods described in Patent Documents 1 and 2 supply the cleaning liquid to the central portion of the substrate while rotating the substrate, thereby cleaning the entire surface of the substrate. And, while rotating the substrate, the supply position of the cleaning liquid on the surface of the substrate is moved from the central side of the substrate to the peripheral side by a predetermined distance, and the drying gas is discharged to the central portion of the substrate to dry the substrate. A step of forming a region, and a step of further moving the supply position of the cleaning liquid on the surface of the substrate toward the peripheral side of the substrate while rotating the substrate. In this case, as the supply position of the cleaning liquid moves to the peripheral edge of the substrate, the dry region formed at the center of the substrate also expands outward due to the action of centrifugal force. Therefore, the cleaning liquid is discharged from the concave portion of the concave / convex pattern toward the outside, and the dissolved resist is discharged together with the cleaning liquid. As a result, development defects are suppressed.

JP 2009-252855 A JP 2012-114409 A

  However, even with the methods of Patent Documents 1 and 2, development defects may occur. Therefore, an object of the present invention is to provide a substrate cleaning apparatus, a substrate cleaning method, and a computer-readable recording medium that can further suppress the occurrence of development defects.

  As a result of intensive studies by the present inventors, it has been found that development defects may occur due to splashing of the cleaning liquid discharged on the surface of the substrate. That is, when the liquid droplets of the cleaning liquid containing the dissolved resist material scatter around the liquid droplets and adhere to the dry region, the dissolved resist material remains on the substrate. As a result, development defects occur. Therefore, the inventors further researched and found that the liquid splash can be effectively suppressed by controlling at least one of the rotation speed of the substrate and the discharge speed of the cleaning liquid.

  That is, a substrate cleaning apparatus according to one aspect of the present invention is a rotary drive unit that rotates a substrate around an axis perpendicular to the surface, and is positioned above the substrate and discharges a cleaning liquid onto the surface of the substrate. A controller that controls at least one liquid nozzle, the number of rotations of the substrate, the movement of the liquid nozzle, and the discharge speed of the cleaning liquid discharged from the liquid nozzle, and the rotation of the cleaning liquid discharged from the liquid nozzle The liquid nozzle is set so that the flow direction of the cleaning liquid is aligned with the linear velocity direction of the substrate at the arrival point that has reached the surface of the substrate that is rotationally driven by the control unit, and the control unit rotates the substrate by the rotational drive unit. And moving the liquid nozzle from the center side to the peripheral side of the substrate so that the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is within a predetermined range. And the rolling speed, for controlling at least one of the discharge rate of the cleaning liquid discharged from the liquid nozzle.

  In the substrate cleaning apparatus according to one aspect of the present invention, the control unit rotates the substrate by the rotation driving unit and moves the liquid nozzle from the central side to the peripheral side of the substrate, and the flow rate of the cleaning liquid at the arrival point At least one of the rotation speed of the substrate and the discharge speed of the cleaning liquid discharged from the liquid nozzle is controlled so that the difference between the linear speed of the substrate at the arrival point is within a predetermined range. Therefore, the difference between the flow rate of the cleaning liquid and the linear velocity of the substrate becomes small at the arrival point. Accordingly, since the cleaning liquid that has reached the substrate easily flows along with the surface of the substrate, the cleaning liquid is less likely to scatter (splash) around. As a result, it is possible to further suppress development defects.

  The control unit sets at least the number of rotations of the substrate and the discharge speed of the cleaning liquid discharged from the liquid nozzle so that the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is ± 25 m / sec. One may be controlled. In this case, since it becomes difficult for the cleaning liquid to scatter (splash) due to the surroundings, it is possible to further suppress development defects.

  A plurality of liquid nozzles having different opening areas and arranged in the order of the opening areas are provided, and the control unit rotates the substrate by the rotation driving unit and moves the liquid nozzles from the center side to the peripheral side of the substrate while opening the opening area. The cleaning liquid may be discharged from the liquid nozzle while switching from the large liquid nozzle to the liquid nozzle having the small opening area. In this case, if the flow rate of the cleaning liquid is the same, the discharge speed of the cleaning liquid is sequentially increased by switching from the liquid nozzle having the large opening area to the liquid nozzle having the small opening area. Therefore, the flow rate of the cleaning liquid at the arrival point can be changed with a simple configuration.

  The control unit includes a plurality of liquid nozzles having different inclinations with respect to the axis and arranged in the order of the inclinations, and the outlets are directed to the surface of the substrate. The cleaning liquid may be discharged from the liquid nozzle while switching toward the edge side while switching from the liquid nozzle having a small inclination to the liquid nozzle having a large inclination. In this case, if the flow rate of the cleaning liquid is the same, the velocity component along the surface of the substrate among the flow rates of the cleaning liquid at the arrival point is sequentially switched by switching the liquid nozzle having a small inclination with respect to the axis to the liquid nozzle having a large inclination with respect to the axis. growing. Therefore, the speed of the cleaning liquid at the arrival point can be changed with a simple configuration.

  The distance between each liquid nozzle and the surface of the substrate and the inclination of each liquid nozzle are set so that the arrival points at which the cleaning liquid discharged from the plurality of liquid nozzles reaches the surface of the substrate are almost the same point. It may be. In this case, even if the liquid nozzle is switched, the cleaning liquid is continuously supplied to the surface of the substrate without interruption. Therefore, the dissolved resist can be sufficiently removed from the substrate, and development defects are greatly suppressed.

  The apparatus further includes at least one gas nozzle that is positioned above the substrate and that discharges a dry gas to the surface of the substrate, and the control unit includes the gas nozzle and the liquid nozzle so that the gas nozzle is positioned closer to the center of the substrate than the liquid nozzle. It may be moved. In this case, since the gas nozzle is located closer to the center of the substrate than the liquid nozzle, a dry region can be easily formed at the center of the surface of the substrate.

  The liquid nozzle may be configured by a collective nozzle in which a plurality of small nozzles having a smaller diameter than the liquid nozzle are bundled. In this case, the flow rate of the cleaning liquid discharged from each small nozzle can be increased by using the small nozzles, and a necessary flow rate of the cleaning liquid can be secured by using a plurality of the small nozzles in a bundle.

  The apparatus further includes at least one other liquid nozzle that is positioned above the substrate and that discharges the cleaning liquid to the surface of the substrate, and the cleaning liquid discharged from the other liquid nozzle is rotated on the surface of the substrate that is rotationally driven by the rotation driving unit. At the other reaching point, the flow direction of the cleaning liquid is set to be in the direction along the linear velocity direction of the substrate, and the control unit rotates the substrate by the rotation driving unit and moves the other liquid nozzle to the center of the substrate. The substrate is moved from the side toward the peripheral side in a direction different from the liquid nozzle, and the difference between the flow rate of the cleaning liquid at the other arrival point and the linear velocity of the substrate at the other arrival point is within a predetermined range. And at least one of the discharge speed of the cleaning liquid discharged from another liquid nozzle may be controlled. In this case, the cleaning liquid is discharged from the liquid nozzles moving in opposite directions to the surface of the substrate. Therefore, a sufficient amount of cleaning liquid can be supplied to a large-sized substrate.

  According to another aspect of the present invention, there is provided a substrate cleaning method in which a cleaning liquid is applied to a central portion of a surface of a substrate from at least one liquid nozzle positioned above the substrate while rotating the substrate about an axis perpendicular to the surface. After discharging, the liquid nozzle is moved from the center side of the substrate toward the peripheral side, and the arrival point where the cleaning liquid discharged from the liquid nozzle reaches the surface of the substrate is moved from the central side of the substrate to the peripheral side. In the cleaning process, the flow direction of the cleaning liquid is in the linear velocity direction of the substrate at the arrival point where the cleaning liquid discharged from the liquid nozzle reaches the surface of the rotating substrate. The flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point are set so as to be oriented, while the substrate is rotated and the liquid nozzle is moved from the center side to the peripheral side of the substrate. So they fall within a predetermined range, the rotational speed of the substrate is at least one of control of the discharge rate of the cleaning liquid discharged from the liquid nozzle.

  In the substrate cleaning method according to another aspect of the present invention, while rotating the substrate and moving the liquid nozzle from the central side toward the peripheral side, the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point At least one of the rotation speed of the substrate and the discharge speed of the cleaning liquid discharged from the liquid nozzle is controlled so that the difference between the two is within a predetermined range. Therefore, the difference between the flow rate of the cleaning liquid and the linear velocity of the substrate becomes small at the arrival point. Accordingly, since the cleaning liquid that has reached the substrate easily flows along with the surface of the substrate, the cleaning liquid is less likely to scatter (splash) around. As a result, it is possible to further suppress development defects.

  In the cleaning process, at least the rotation speed of the substrate and the discharge speed of the cleaning liquid discharged from the liquid nozzle are set so that the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is ± 25 m / sec. One may be controlled. In this case, since it becomes difficult for the cleaning liquid to scatter (splash) due to the surroundings, it is possible to further suppress development defects.

  In the cleaning process, while the substrate is rotated and the liquid nozzle is moved from the center side to the peripheral side of the substrate, the liquid flow rate at the arrival point increases as the liquid nozzle moves toward the peripheral edge of the substrate. The discharge speed of the cleaning liquid discharged from the nozzle may be controlled. In this case, since the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is within a predetermined range, the flow rate of the cleaning liquid at the arrival point increases as the liquid nozzle moves toward the peripheral edge of the substrate. As a result, the linear velocity of the substrate also increases. For this reason, the drying region easily spreads outward as the liquid nozzle moves. Therefore, it is possible to suppress the extremely slow speed (the so-called drying delay) at which the drying region spreads outside compared to the speed at which the liquid nozzle moves to the peripheral edge of the substrate. That is, resist dissolution remains on the substrate due to a delay in drying, and development defects are greatly suppressed.

  In the cleaning process, while rotating the substrate and moving the liquid nozzle from the center side to the peripheral side of the substrate, the rotation speed of the substrate is controlled so that the centripetal acceleration of the substrate at the arrival point is substantially constant. May be. In this case, the centrifugal force acting on the cleaning liquid at the arrival position is substantially constant in the direction from the central portion to the peripheral portion of the wafer. For this reason, the drying region easily spreads outward as the liquid nozzle moves. Therefore, it is possible to suppress the extremely slow speed (the so-called drying delay) at which the drying region spreads outside compared to the speed at which the liquid nozzle moves to the peripheral edge of the substrate. That is, resist dissolution remains on the substrate due to a delay in drying, and development defects are greatly suppressed.

  In the cleaning process, when cleaning the substrate surface by discharging the cleaning liquid to the surface of the substrate from a plurality of liquid nozzles having different opening areas and arranged in order of the opening area, the substrate is rotated and the liquid nozzle is moved from the center side of the substrate. The cleaning liquid may be ejected from the liquid nozzle while switching in the order of the liquid nozzle having a large opening area and the liquid nozzle having a small opening area while moving toward the peripheral side. In this case, if the flow rate of the cleaning liquid is the same, the discharge speed of the cleaning liquid is sequentially increased by switching from the liquid nozzle having the large opening area to the liquid nozzle having the small opening area. Therefore, the flow rate of the cleaning liquid at the arrival point can be changed with a simple configuration.

  In the cleaning step, the substrate is cleaned when the substrate surface is cleaned by discharging the cleaning liquid onto the substrate surface from a plurality of liquid nozzles having different inclinations with respect to the axes and arranged in the order of the inclination, and the outlets facing the substrate surface. The cleaning liquid may be discharged from the liquid nozzle while rotating and moving the liquid nozzle from the center side to the peripheral side of the substrate while switching from the liquid nozzle having a small inclination to the liquid nozzle having a large inclination. In this case, if the flow rate of the cleaning liquid is the same, the velocity component along the surface of the substrate among the flow rates of the cleaning liquid at the arrival point is sequentially switched by switching the liquid nozzle having a small inclination with respect to the axis to the liquid nozzle having a large inclination with respect to the axis. growing. Therefore, the speed of the cleaning liquid at the arrival point can be changed with a simple configuration.

  In the cleaning process, the substrate is rotated and a dry gas is discharged from at least one gas nozzle to the center of the surface of the substrate to form a dry region in the center of the surface of the substrate, and then the substrate is rotated and the liquid nozzle is moved to the substrate. The substrate rotation speed and the liquid nozzle are discharged so that the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is within a predetermined range. At least one of the discharge speed of the cleaning liquid to be performed may be controlled. In this case, as the liquid nozzle moves to the peripheral edge of the substrate, the dry region formed in the central portion of the substrate also expands outward due to the action of centrifugal force. For this reason, the cleaning liquid is discharged toward the outside, and the dissolved resist is hardly left in the dry region. In addition, coupled with the fact that liquid splash is less likely to occur, the occurrence of development defects is greatly suppressed.

  In the cleaning step, the cleaning liquid is discharged from the plurality of liquid nozzles onto the surface of the substrate, and the plurality of liquid nozzles and the plurality of liquid nozzles are discharged from the plurality of gas nozzles to the surface of the substrate toward the center side from the arrival point of the cleaning liquid While moving the gas nozzle from the center side to the peripheral side of the substrate, the dry gas may be discharged from the gas nozzle while sequentially switching each gas nozzle in accordance with the switching of the plurality of liquid nozzles. In this case, as the liquid nozzle from which the cleaning liquid is discharged is sequentially switched, the dry gas is discharged from the gas nozzle located near the liquid nozzle from which the cleaning liquid is being discharged, so that the dry gas reaches the substrate position. Since the distance from the position where the cleaning liquid reaches the substrate is maintained, so-called drying delay is suppressed. For this reason, the resist melt hardly remains on the substrate due to the delay in drying, and development defects are greatly suppressed.

  A computer-readable recording medium according to another aspect of the present invention records a program for causing a substrate cleaning apparatus to execute any of the above substrate cleaning methods. In this specification, the computer-readable recording medium includes a non-transitory computer recording medium (for example, various main storage devices or auxiliary storage devices) and a propagation signal (transitory computer). recording medium) (for example, a data signal that can be provided via a network).

  According to the present invention, it is possible to provide a substrate cleaning apparatus, a substrate cleaning method, and a computer-readable recording medium that can further suppress the occurrence of development defects.

FIG. 1 is a perspective view showing a coating / developing system. 2 is a cross-sectional view taken along line II-II in FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a cross-sectional view showing the substrate processing apparatus. FIG. 5 is a top view showing the substrate processing apparatus. 6A is a top view showing the cleaning / drying head, and FIG. 6B is a side view showing the cleaning / drying head. FIG. 7 is a diagram for explaining a step of supplying a developing solution. FIG. 8 is a diagram for explaining a process of supplying the cleaning liquid. FIG. 9 is a diagram for explaining a process of supplying the cleaning liquid and the dry gas. FIG. 10 is a diagram for explaining a process of supplying the cleaning liquid and the dry gas. FIG. 11 is a diagram for explaining changes in the number of rotations of the wafer and the flow rate of the cleaning liquid. FIG. 12 is a diagram showing the relationship between the position of the head in the wafer radial direction and the drying delay distance during linear velocity control. FIG. 13 is a diagram illustrating the relationship between the position of the head in the wafer radial direction and the drying delay distance during centripetal acceleration control. FIG. 14 is a diagram showing the relationship between the position of the head in the wafer radial direction and the number of wafer rotations. FIG. 15 is a diagram showing the relationship between the position of the head in the wafer radial direction and the wafer linear velocity. FIG. 16 is a diagram illustrating the relationship between the head moving speed and the processing time. FIG. 17 is a diagram showing another example of the cleaning / drying head. FIG. 18 is a diagram illustrating the collecting nozzle. FIG. 19 is a diagram for explaining another example of the change in the number of rotations of the wafer and the flow rate of the cleaning liquid. FIG. 20 is a diagram for explaining another example of the process of supplying the cleaning liquid and the dry gas. FIG. 21 is a diagram for explaining another example of the change in the number of rotations of the wafer and the flow rate of the cleaning liquid.

  Embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are exemplifications for explaining the present invention and are not intended to limit the present invention to the following contents. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  First, an outline of the configuration of the coating / developing apparatus 1 shown in FIGS. 1 to 3 will be described. The coating / developing apparatus 1 performs a process of applying a resist material to the surface of the wafer (substrate) W to form a resist film before the exposure process by the exposure apparatus E1. The coating / developing apparatus 1 performs a development process on the resist film formed on the surface of the wafer W after the exposure process by the exposure apparatus E1. In the present embodiment, the wafer W has a disk shape, but a wafer having a part of a circle cut out or a shape other than a circle such as a polygon may be used.

  As shown in FIGS. 1 and 2, the coating / developing apparatus 1 includes a carrier block S <b> 1, a processing block S <b> 2, an interface block S <b> 3, and a control unit CU that functions as control means for the coating / developing apparatus 1. . In the present embodiment, the carrier block S1, the processing block S2, the interface block S3, and the exposure apparatus E1 are arranged in series in this order.

  As shown in FIGS. 1 and 3, the carrier block S <b> 1 includes a carrier station 12 and a carry-in / carry-out unit 13. The carrier station 12 supports a plurality of carriers 11. The carrier 11 accommodates a plurality of wafers W in a sealed state. The carrier 11 has an open / close door (not shown) for taking in and out the wafer W on the side surface 11a side. The carrier 11 is detachably installed on the carrier station 12 so that the side surface 11a faces the loading / unloading unit 13 side.

  As shown in FIGS. 1 to 3, the carry-in / carry-out unit 13 includes open / close doors 13 a corresponding to the plurality of carriers 11 on the carrier station 12. When the open / close door of the side surface 11a and the open / close door 13a of the carry-in / carry-out unit 13 are opened simultaneously, the inside of the carrier 11 and the carry-in / carry-out unit 13 communicate with each other. As shown in FIGS. 2 and 3, the carry-in / carry-out unit 13 incorporates a delivery arm A <b> 1. The delivery arm A1 takes out the wafer W from the carrier 11 and delivers it to the processing block S2. The delivery arm A1 receives the wafer W from the processing block S2 and returns it to the carrier 11.

  The processing block S2 is adjacent to the carrier block S1 and connected to the carrier block S1, as shown in FIGS. As shown in FIGS. 1 and 2, the processing block S2 includes a lower antireflection film formation (BCT) block 14, a resist film formation (COT) block 15, an upper antireflection film formation (TCT) block 16, and A development processing (DEV) block 17. The DEV block 17, the BCT block 14, the COT block 15, and the TCT block 16 are arranged in this order from the bottom side.

  As shown in FIG. 2, the BCT block 14 includes a coating unit (not shown), a heating / cooling unit (not shown), and a transfer arm A2 for transferring the wafer W to these units. Yes. The coating unit applies a chemical solution for forming an antireflection film to the surface of the wafer W. The heating / cooling unit heats the wafer W using, for example, a hot plate, and then cools the wafer W using, for example, a cooling plate. Thus, a lower antireflection film is formed on the surface of the wafer W.

  As shown in FIG. 2, the COT block 15 includes a coating unit (not shown), a heating / cooling unit (not shown), and a transfer arm A3 for transferring the wafer W to these units. Yes. The coating unit applies a chemical solution (resist material) for forming a resist film on the lower antireflection film. The heating / cooling unit heats the wafer W using, for example, a hot plate, and then cools the wafer W using, for example, a cooling plate. Thus, a resist film is formed on the lower antireflection film of the wafer W. The resist material may be a positive type or a negative type.

  As shown in FIG. 2, the TCT block 16 includes a coating unit (not shown), a heating / cooling unit (not shown), and a transfer arm A4 for transferring the wafer W to these units. Yes. The coating unit applies a chemical solution for forming an antireflection film on the resist film. The heating / cooling unit heats the wafer W using, for example, a hot plate, and then cools the wafer W using, for example, a cooling plate. Thus, an upper antireflection film is formed on the resist film of the wafer W.

  As shown in FIGS. 2 and 3, the DEV block 17 transports wafers W to a plurality of development processing units (substrate processing apparatuses) U1, a plurality of heating / cooling units (heat treatment units) U2, and these units. And a transfer arm A6 that transfers the wafer W between before and after the processing block S2 without passing through these units.

  The development processing unit U1 performs development processing on the exposed resist film, as will be described later. The heating / cooling unit U2 heats the resist film on the wafer W, for example, by heating the wafer W with a hot plate. The heating / cooling unit U2 cools the heated wafer W by, for example, a cooling plate. The heating / cooling unit U2 performs heat treatment such as post-exposure baking (PEB) and post-baking (PB). PEB is a process for heating the resist film before the development process. PB is a process of heating the resist film after the development process.

  As shown in FIGS. 1 to 3, a shelf unit U <b> 10 is provided on the carrier block S <b> 1 side in the processing block S <b> 2. The shelf unit U10 includes a plurality of cells C30 to C38. The cells C30 to C38 are arranged in the vertical direction between the DEV block 17 and the TCT block 16. A lifting arm A7 is provided in the vicinity of the shelf unit U10. The lift arm A7 transports the wafer W between the cells C30 to C38.

  A shelf unit U11 is provided on the interface block S3 side in the processing block S2. The shelf unit U11 has a plurality of cells C40 to C42. The cells C40 to C42 are arranged adjacent to the DEV block 17 in the vertical direction.

  As shown in FIGS. 1 to 3, the interface block S3 is located between the processing block S2 and the exposure apparatus E1, and is connected to each of the processing block S2 and the exposure apparatus E1. As shown in FIGS. 2 and 3, the interface block S3 includes a delivery arm A8. The transfer arm A8 transfers the wafer W from the shelf unit U11 of the processing block S2 to the exposure apparatus E1. The transfer arm A8 receives the wafer W from the exposure apparatus E1, and returns the wafer W to the shelf unit U11.

  The control device CU is a computer for control and includes a storage unit CU1 and a control unit CU2 as shown in FIG. The storage unit CU1 stores a program for operating each part of the coating / developing apparatus 1 and each part of the exposure apparatus E1. The storage unit CU1 is, for example, a semiconductor memory, an optical recording disk, a magnetic recording disk, or a magneto-optical recording disk. The program may be included in an external storage device separate from the storage unit CU1 or an intangible medium such as a propagation signal. The program may be installed in the storage unit CU1 from these other media, and the program may be stored in the storage unit CU1. The control unit CU2 controls the operation of each unit of the coating / developing apparatus 1 and each unit of the exposure apparatus E1 based on the program read from the storage unit CU1. The control unit CU further includes a display unit (not shown) that displays a processing condition setting screen and an input unit (not shown) that allows the operator to input the processing conditions. Depending on the conditions, each part of the coating / developing apparatus 1 and each part of the exposure apparatus E1 may be operated.

  Next, an outline of the operation of the coating / developing apparatus 1 will be described. First, the carrier 11 is installed in the carrier station 12. At this time, one side surface 11 a of the carrier 11 is directed to the open / close door 13 a of the carry-in / carry-out unit 13. Subsequently, the opening / closing door of the carrier 11 and the opening / closing door 13a of the loading / unloading section 13 are both opened, and the wafer W in the carrier 11 is taken out by the transfer arm A1, and any of the shelf units U10 of the processing block S2 is selected. It is sequentially transported to that cell.

  After the wafer W is transferred to any cell of the shelf unit U10 by the transfer arm A1, the wafer W is sequentially transferred to the cell C33 corresponding to the BCT block 14 by the lifting arm A7. The wafer W transferred to the cell C33 is transferred to each unit in the BCT block 14 by the transfer arm A2. In the process in which the wafer W is transferred through the BCT block 14 by the transfer arm A2, a lower antireflection film is formed on the surface of the wafer W.

  The wafer W on which the lower antireflection film is formed is transferred to the cell C34 above the cell C33 by the transfer arm A2. The wafer W transferred to the cell C34 is transferred to the cell C35 corresponding to the COT block 15 by the lifting arm A7. The wafer W transferred to the cell C35 is transferred to each unit in the COT block 15 by the transfer arm A3. In the process in which the wafer W is transferred through the COT block 15 by the transfer arm A3, a resist film is formed on the lower antireflection film.

  The wafer W on which the resist film is formed is transferred to the cell C36 above the cell C35 by the transfer arm A3. The wafer W transferred to the cell C36 is transferred to the cell C37 corresponding to the TCT block 16 by the lifting arm A7. The wafer W transferred to the cell C37 is transferred to each unit in the TCT block 16 by the transfer arm A4. In the process in which the wafer W is transported through the TCT block 16 by the transport arm A4, an upper antireflection film is formed on the resist film.

  The wafer W on which the upper antireflection film is formed is transferred to the cell C38 above the cell C37 by the transfer arm A4. The wafer W transferred to the cell C38 is transferred to the cell C32 by the lift arm A7 and then transferred to the cell C42 of the shelf unit U11 by the transfer arm A6. The wafer W transferred to the cell C42 is transferred to the exposure apparatus E1 by the transfer arm A8 of the interface block S3, and a resist film exposure process is performed in the exposure apparatus E1. The wafer W subjected to the exposure processing is transferred to the cells C40 and C41 below the cell C42 by the transfer arm A8.

  The wafer W transferred to the cells C40 and C41 is transferred to each unit in the DEV block 17 by the transfer arm A5, and development processing is performed. As a result, a resist pattern (uneven pattern) is formed on the surface of the wafer W. The wafer W on which the resist pattern is formed is transferred by the transfer arm A5 to cells C30 and C31 corresponding to the DEV block 17 in the shelf unit U10. The wafer W transferred to the cells C30 and C31 is transferred to a cell accessible by the transfer arm A1 by the lift arm A7, and returned to the carrier 11 by the transfer arm A1.

  The configuration and operation of the coating / developing apparatus 1 described above are merely examples. The coating / developing apparatus 1 may include a liquid processing unit such as a coating unit or a development processing unit, a pre-processing / post-processing unit such as a heating / cooling unit, and a transport device. That is, the number, type, layout, etc. of each unit can be changed as appropriate.

  Next, the development processing unit (substrate processing apparatus) U1 will be described in more detail. As shown in FIG. 4, the development processing unit U <b> 1 includes a rotation holding unit 20, an elevating device 22, a developer supply unit 23, a front surface cleaning / drying unit 100, and a back surface cleaning unit 26.

  The rotation holding part 20 has a main body part 20a incorporating a power source such as an electric motor, a rotary shaft 20b extending vertically upward from the main body part 20a, and a chuck 20c provided at the tip of the rotary shaft 20b. The main body 20a rotates the rotating shaft 20b and the chuck 20c with a power source. The chuck 20c supports the central portion of the wafer W and holds the wafer W substantially horizontally by suction, for example. That is, the rotation holding unit 20 rotates the wafer W around a central axis (vertical axis) perpendicular to the surface of the wafer W in a state where the wafer W is substantially horizontal. In the present embodiment, as shown in FIGS. 4 and 5 and the like, the rotation holding unit 20 rotates the wafer W in the clockwise direction when viewed from above.

  The lifting device 22 is attached to the rotation holding unit 20 and moves the rotation holding unit 20 up and down. Specifically, the elevating device 22 has a raised position (delivery position) for delivering the wafer W between the transfer arm A5 and the chuck 20c, and a lowered position (development position) for performing the development process. In the meantime, the rotation holding part 20 (chuck 20c) is moved up and down.

  A cup 30 is provided around the rotation holding unit 20. When the wafer W rotates, a liquid (described in detail later) supplied to the surface of the wafer W is shaken off and dropped, but the cup 30 functions as a container that receives the dropped liquid. The cup 30 includes an annular bottom plate 31 that surrounds the rotation holding portion 20, a cylindrical outer wall 32 that protrudes vertically upward from the outer edge of the bottom plate 31, and a cylindrical inner wall 33 that protrudes vertically upward from the inner edge of the bottom plate 31. And have.

  All parts of the outer wall 32 are located outside the wafer W held by the chuck 20c. The upper end 32a of the outer wall 32 is positioned above the wafer W held by the rotation holding unit 20 in the lowered position. A portion of the outer wall 32 on the upper end 32a side is an inclined wall portion 32b that is inclined inward as it goes upward. The entire portion of the inner wall 33 is located inside the outer edge of the wafer W held by the chuck 20c. The upper end 33a of the inner wall 33 is positioned below the wafer W held by the rotation holding unit 20 at the lowered position.

  A partition wall 34 protruding vertically upward from the upper surface of the bottom plate 31 is provided between the inner wall 33 and the outer wall 32. That is, the partition wall 34 surrounds the inner wall 33. A liquid discharge hole 31 a is formed in a portion of the bottom plate 31 between the outer wall 32 and the partition wall 34. A drainage pipe 35 is connected to the liquid discharge hole 31a. A gas discharge hole 31 b is formed in a portion of the bottom plate 31 between the partition wall 34 and the inner wall 33. An exhaust pipe 36 is connected to the gas discharge hole 31b.

  On the inner wall 33, an umbrella-shaped portion 37 that projects outward from the partition wall 34 is provided. The liquid that is shaken off from the wafer W and dropped is guided between the outer wall 32 and the partition wall 34 and discharged from the liquid discharge hole 31a. A gas or the like generated from the liquid enters between the partition wall 34 and the inner wall 33, and the gas is discharged from the gas discharge hole 31b.

  The upper part of the space surrounded by the inner wall 33 is closed by a partition plate 38. The main body 20 a of the rotation holding unit 20 is located below the partition plate 38. The chuck 20 c is located above the partition plate 38. The rotating shaft 20b is inserted into a through hole formed at the center of the partition plate 38.

  As shown in FIGS. 4 and 5, the developer supply unit 23 includes a developer (processing liquid) supply source 23a, a developer head 23c, and a moving body 23d. The supply source 23a includes a developer storage container, a pump, a valve, and the like. The developer head 23c is connected to the supply source 23a through the supply pipe 23b. In response to a control signal from the control unit CU, the developer head 23c discharges the developer supplied from the supply source 23a to the surface Wa of the wafer W from the liquid nozzle h1. The liquid nozzle h <b> 1 opens downward toward the surface Wa of the wafer W. As shown in FIG. 5, the liquid nozzle h <b> 1 has a slit shape extending along the radial direction of the wafer W.

  The moving body 23d is connected to the developer head 23c via the arm 23e. In response to the control signal from the control unit CU, the moving body 23d moves on the guide rail 40 that extends horizontally outside the outer wall 32, thereby moving the developer head 23c in the horizontal direction. As a result, the developer head 23c moves along the radial direction of the wafer W above the wafer W at the lowered position and on a straight line perpendicular to the central axis of the wafer W.

As shown in FIGS. 4 and 5, the surface cleaning / drying unit 100 includes a cleaning liquid (rinsing liquid) supply source 100a, a drying gas supply source 100b, a cleaning / drying head 100c, and a moving body 100d. Have. The supply source 100a includes a cleaning liquid storage container, a pump, a valve, and the like. The cleaning liquid is, for example, pure water or DIW (Deionized Water). The supply source 100a is connected to the cleaning / drying head 100c through a supply pipe 100e. The supply source 100b includes a dry gas storage container, a pump, a valve, and the like. The dry gas is an inert gas such as N ₂ . The supply source 100b is connected to the cleaning / drying head 100c through a supply pipe 100f.

  The cleaning / drying head 100c receives a control signal from the control unit CU and discharges the cleaning liquid supplied from the supply source 100a onto the surface Wa of the wafer W (four liquid nozzles in this embodiment) h2 to h2. h5, and a gas nozzle h6 that discharges the dry gas supplied from the supply source 100b to the surface Wa of the wafer W in response to a control signal from the control unit CU. These nozzles h <b> 2 to h <b> 6 are opened downward toward the surface Wa of the wafer W.

  As shown in FIGS. 4 to 6, the nozzles h <b> 6, h <b> 2 to h <b> 5 are arranged in this order from the center of the wafer W toward the peripheral edge along the radial direction of the wafer W as viewed from above. As shown in FIG. 5 and FIG. 6A, the nozzles h <b> 5 to h <b> 2 and h <b> 6 are from the upstream side in the rotational direction of the wafer W toward the downstream side along the tangential direction of the wafer W as viewed from above. They are arranged in this order.

  The opening areas (opening diameters) of the liquid nozzles h2 to h5 are set so as to decrease in this order as shown in FIGS. As shown in FIG. 6B, the front end sides (exit sides) of the liquid nozzles h2 to h5 are inclined with respect to the central axis of the wafer W, and the inclination with respect to the central axis increases in this order. Has been. The inclination of the tip side (exit side) of the liquid nozzles h2 to h5 and the linear distance between the liquid nozzles h2 to h5 and the surface Wa of the wafer W when the wafer W is cleaned are shown in FIG. As seen from the radial direction of the wafer W, the cleaning liquid discharged from the liquid nozzles h <b> 2 to h <b> 5 reaches the substantially same point P on the surface Wa of the wafer W. Since the liquid nozzles h2 to h5 are set as described above, the flow rate of the cleaning liquid discharged from each of the liquid nozzles h2 to h5 increases in the order of the liquid nozzles h2 to h5.

  The direction in which the tip side (exit side) of the liquid nozzles h2 to h5 is inclined is a direction along the tangential direction of the wafer W and from the upstream side to the downstream side in the rotation direction of the wafer W as viewed from above. Accordingly, at the arrival point P where the cleaning liquid discharged from each of the liquid nozzles h <b> 2 to h <b> 5 has reached the surface Wa of the wafer W, the flow direction of the cleaning liquid is in the direction along the linear velocity direction of the wafer W. Here, the linear velocity means a tangential velocity at a certain point on the surface Wa of the wafer W, and is distinguished from an angular velocity. When the distance from the center of the wafer W to the point is r (vector amount), the angular velocity at the point is ω (vector amount), and the linear velocity at the point is v (vector amount), the linear velocity v is the distance r. And the angular product ω (v = r × ω).

  The moving body 100d is connected to the cleaning / drying head 100c via the arm 100g. The moving body 100d moves on the guide rail 40 in response to a control signal from the control unit CU, thereby moving the cleaning / drying head 100c in the horizontal direction. As a result, the cleaning / drying head 100c moves along the radial direction of the wafer W above the wafer W at the lowered position and on a straight line perpendicular to the central axis of the wafer W.

  As shown in FIG. 4, the back surface cleaning unit 26 includes a back surface cleaning liquid (back surface rinsing liquid) supply source 26a and a back surface cleaning liquid head 26c. The supply source 26a includes a back surface cleaning liquid storage container, a pump, a valve, and the like. The back surface cleaning liquid is pure water, DIW, or a water-soluble organic solvent. Examples of the water-soluble organic solvent include isopropyl alcohol. The back surface cleaning liquid head 26c is connected to the supply source 26a through the supply pipe 26b. The back surface cleaning liquid head 26 c is disposed on the partition plate 38, and the supply pipe 26 b is inserted through a through hole formed in the partition plate 38. The back surface cleaning liquid head 26c receives the control signal from the control unit CU and discharges the back surface cleaning liquid supplied from the supply source 26a to the back surface Wb of the wafer W from the liquid nozzle h7. The liquid nozzle h7 is opened obliquely upward on the peripheral side of the wafer W and toward the back surface Wb of the wafer W.

  Next, a method for forming a resist pattern (uneven pattern) on the surface Wa of the wafer W using the development processing unit U1 will be described in detail. First, the control device CU instructs the lifting device 22 to raise the chuck 20c to the raised position. In this state, the wafer W is carried into the development processing unit U1 by the transfer arm A5. Before the wafer W is carried into the development processing unit U1, a resist film R (see FIG. 7) is formed on the surface Wa of the wafer W, and the resist film R is subjected to exposure processing by the exposure apparatus E1. Has been.

  When the wafer W is placed on the chuck 20c with the surface Wa on which the resist film R is disposed facing upward, the control unit CU instructs the chuck 20c to attract and hold the wafer W on the chuck 20c. Subsequently, the control unit CU instructs the lifting device 22 to lower the chuck 20c to the lowered position.

  Subsequently, the control unit CU instructs the rotation holding unit 20 (main body unit 20a) to rotate the wafer W (see FIG. 7A). In the present embodiment, the wafer W is rotated clockwise as viewed from above. The control unit CU instructs the moving body 23d and the supply source 23a to move the developer head 23c from the peripheral side to the center side of the wafer W while the wafer W is rotating, and to supply the developer L1 from the liquid nozzle h1. It is discharged onto the surface Wa of the wafer W (see FIG. 7A). As a result, the developer L1 is spirally supplied from the peripheral side of the wafer W to the center side on the surface Wa of the wafer W, and the entire surface Wa of the wafer W is covered with the developer L1 (FIG. 7 ( b)). Subsequently, the control unit CU instructs the moving body 23d and the supply source 23a to stop the discharge of the developer L1 from the liquid nozzle h1 and retract the developer head 23c to the outside of the wafer W.

  Subsequently, the control unit CU instructs the moving body 100d to move the cleaning / drying head 100c to the center of the wafer W. When the liquid nozzle h2 reaches substantially the center of the wafer W, the control unit CU instructs the supply source 100a to discharge the cleaning liquid L2 from the liquid nozzle h2 while the wafer W is rotating (FIGS. 8A and 10). (See (a)). At this time, the lower limit of the rotation speed ω1 of the wafer W may be, for example, about 500 rpm or about 1000 rpm. At this time, the upper limit of the rotational speed ω1 of the wafer W may be, for example, about 15000 rpm or about 1000 rpm. The lower limit of the discharge time of the cleaning liquid L2 from the liquid nozzle h2 may be, for example, about 15 seconds or about 30 seconds. The upper limit of the discharge time of the cleaning liquid L2 from the liquid nozzle h2 may be, for example, about 600 seconds or about 30 seconds.

  Of the exposed resist film R, the resist dissolved in the reaction with the developer L1 is washed away together with the developer L1 by the cleaning liquid L2 (see FIG. 8B). These dissolved resist, developer L1 and cleaning liquid L2 are shaken off around the wafer W by the centrifugal force accompanying the rotation of the wafer W and dropped. Thus, a resist pattern RP is formed on the surface Wa of the wafer W (see FIG. 8B). The resist pattern RP is a concave / convex pattern having convex portions Ra and concave portions Rb.

  Subsequently, the control unit CU instructs the moving body 100d to move the cleaning / drying head 100c to the peripheral side of the wafer W while maintaining the rotation of the wafer W and the discharge of the cleaning liquid L2 from the liquid nozzle h2. When the gas nozzle h6 reaches the substantially central portion of the wafer W, the control unit CU instructs the supply source 100b to discharge the dry gas G from the gas nozzle h6 during the rotation of the wafer W (FIGS. 9A and 10). b)). The time from the start of discharge of the dry gas G to the stop of discharge can be set to about 5 seconds, for example.

  As a result, the cleaning liquid L2 on the central portion of the wafer W is blown away and evaporated, and a dry region D is formed in the central portion of the wafer W. Here, the dry region D is a region in which the surface Wa of the wafer W is exposed by the evaporation of the cleaning liquid L2, and very few (for example, micro-order) droplets adhere to the surface Wa. It is also included. The dry region D expands from the central portion of the wafer W toward the peripheral side by centrifugal force generated by the rotation of the wafer W.

  Subsequently, the control unit CU instructs the rotation holding unit 20 (main body unit 20a), the moving body 100d and the supply source 100a to move the cleaning / drying head 100c from the central part of the wafer W to the peripheral side at a predetermined speed. While changing the rotation speed ω2 of the wafer W according to predetermined conditions, the liquid nozzles h2 to h5 that discharge the cleaning liquid L2 are switched. The moving speed of the cleaning / drying head 100c may be set to be a constant speed within a range of about 2.5 mm / sec to 10 mm / sec, for example. In the cleaning process of the wafer W, the cleaning / drying head 100c is moved from the center side of the wafer W to the peripheral side so that the gas nozzle h6 is positioned closer to the center side of the wafer W than the liquid nozzles h2 to h5 when viewed from above. .

The rotational speed ω2 of the wafer W is such that the cleaning liquid L2 discharged from the liquid nozzles h2 to h5 reaches the surface Wa of the wafer W (arrival point) P while the cleaning / drying head 100c is moving. The centripetal acceleration is set to be substantially constant. Here, centripetal acceleration a (vector amount), the angular velocity omega and (vector quantity), the distance r (vector quantity) from the center of the wafer W to the point P and with ^{a, a = - | ω | 2} · represented by r. Therefore, since the distance r increases as the cleaning / drying head 100c moves toward the peripheral edge of the wafer W, the rotational speed ω2 (angular velocity ω) of the wafer W is gradually reduced when the centripetal acceleration a is constant (FIG. 11). reference). However, when the cleaning / drying head 100c moves near the center of the wafer W, if the rotation speed ω2 of the wafer W is set so that the centripetal acceleration a is constant, the rotation speed ω2 of the wafer W becomes extremely large, Liquid splash is likely to occur. Therefore, while the cleaning / drying head 100c moves in the vicinity of the center of the wafer W, the rotational speed ω2 of the wafer W is set so as not to exceed a predetermined upper limit (see FIG. 11).

  The liquid nozzles h2 to h5 are sequentially switched so that the difference between the flow rate of the cleaning liquid L2 at the arrival point P and the linear velocity of the wafer W at the arrival point P is within a predetermined range (FIG. 9B). FIG. 9 (c), FIG. 10 (c) and FIG. 10 (d)). Specifically, as described above, since the rotational speed ω2 of the wafer W is controlled so as to keep the centripetal acceleration a constant, the arrival point P increases as the cleaning / drying head 100c moves toward the peripheral edge of the wafer W. The linear velocity of the wafer W increases in proportion to the square root of the distance r. Therefore, as the cleaning / drying head 100c moves toward the periphery of the wafer W, the cleaning liquid L2 is discharged in the order of the liquid nozzles h2 to h5 to increase the flow rate of the cleaning liquid L2, so that the difference falls within a predetermined range. Controlled. For example, the difference may be set to be within a range of ± 25 m / sec. When the liquid nozzles h2 to h5 are switched, the cleaning liquid L2 is simultaneously discharged from the two liquid nozzles before and after the switching so that the cleaning liquid L2 is not interrupted on the surface Wa of the wafer W, or the cleaning / drying head 100c is moved to the wafer. You may make it move so that it may return a little to the center side of W.

  Subsequently, when the cleaning of the entire surface Wa of the wafer W is completed, the control unit CU instructs the moving body 100d and the rotation holding unit 20 (main body unit 20a) to move the cleaning / drying head 100c to the outside of the wafer W. Thereafter, the wafer W is rotated at a predetermined number of revolutions to dry the wafer W (see FIGS. 9D, 10E, and 11). The number of rotations of the wafer W at this time may be set to about 1500 rpm to 2000 rpm, for example.

  Through the above steps, a resist pattern (uneven pattern) RP is formed on the surface Wa of the wafer W. Accordingly, the development processing unit U1 also functions as an apparatus for cleaning the wafer W during the development processing. The back surface Wb of the wafer W is cleaned by the back surface cleaning unit 26 after the cleaning liquid is discharged from the liquid nozzle h2 onto the surface Wa of the wafer W and before the surface Wa of the wafer W is dried. Also good.

  By the way, if the resist melt dissolved by the developer remains on the surface of the wafer, a desired resist pattern (uneven pattern) cannot be obtained and development defects may occur. In order to suppress this development defect, it can be considered as one method to form a dry region by spraying a dry gas to the central portion of the wafer while discharging a cleaning liquid onto the surface of the wafer. At this time, while the head having the liquid nozzle is moving, the wafer is rotated so that the linear velocity of the wafer at the point (arrival point) where the cleaning liquid discharged from the liquid nozzle reaches the surface of the wafer is substantially constant. A number can be set. In this case, if the flow rate of the cleaning liquid discharged from the liquid nozzle is also constant, the difference between the flow rate and the linear velocity of the wafer can be kept within a certain range, so that liquid splash can be suppressed. However, when such control is performed to keep the linear velocity constant, the number of rotations of the wafer decreases as the head moves toward the peripheral edge of the wafer, so that the speed at which the dry region spreads outward becomes slower. Therefore, the faster the head is moved, the greater the distance between the head and the drying area, and the more the drying delay becomes more pronounced (see FIG. 12). As a result, the head moving speed must be lowered in order to suppress development defects due to delay in drying, and therefore the processing time becomes long when the method is applied to a large wafer.

  Therefore, while the head having the liquid nozzle is moving, the wafer is rotated so that the centripetal acceleration of the wafer at the point (arrival point) at which the cleaning liquid discharged from the liquid nozzle reaches the surface of the wafer is substantially constant. A number can be set. In this way, even if the moving speed of the head is high, it is possible to suppress the drying delay (see FIG. 13). However, in this case, if the number of rotations of the wafer that does not cause development defects due to drying delay is determined with respect to the moving speed of the head, the number of rotations of the wafer becomes higher than in the case of the control for keeping the linear velocity constant ( (See FIG. 14). Therefore, if the flow rate of the cleaning liquid discharged from the liquid nozzle remains constant, the difference between the flow rate and the linear velocity of the wafer increases as the head moves toward the peripheral edge of the wafer, and development defects due to liquid splashing may occur. . In particular, when the difference exceeded 25 m / sec, occurrence of liquid splash was observed (see FIG. 15). Therefore, even in the case of such control that keeps the centripetal acceleration constant, the head moving speed has to be lowered in order to suppress development defects caused by liquid splashing, so the method is applied to a large wafer. It was difficult.

  Therefore, the present inventors have conducted intensive research on a technique that can suppress the occurrence of development defects due to delay in drying and liquid splashing even when the moving speed of the head is high, and can shorten the processing time. As a result, the difference between the flow velocity of the cleaning liquid L2 at the arrival point P and the linear velocity of the wafer W at the arrival point P is set to a predetermined value while adopting the control for making the centripetal acceleration constant as in the above embodiment. It came to develop a new method of making it within the range.

  Specifically, in the present embodiment, the flow rate of the cleaning liquid L2 at the arrival point P and the arrival point P while the wafer W is rotating and the cleaning / drying head 100c is moving from the center side toward the peripheral side of the wafer W. The liquid nozzles h2 to h5 are sequentially switched so that the difference from the linear velocity of the wafer W is within a predetermined range. Therefore, at the arrival point P, the difference between the flow rate of the cleaning liquid L2 and the linear velocity of the wafer W is reduced. Accordingly, since the cleaning liquid L2 that has reached the wafer W easily flows along with the surface Wa of the wafer W, the cleaning liquid L2 is less likely to splash (splash) around. As a result, it is possible to further suppress development defects.

  In the present embodiment, the dry region D is formed in the center of the surface Wa of the wafer W by discharging the dry gas G from the gas nozzle h6. Therefore, as the cleaning / drying head 100c moves to the peripheral portion of the wafer W, the drying region D formed in the central portion of the wafer W also expands outward due to the action of centrifugal force. Therefore, the cleaning liquid L2 is discharged outward from the recess Rb of the resist pattern RP, and the dissolved resist is discharged together with the cleaning liquid. In addition, coupled with the fact that liquid splash is less likely to occur, the occurrence of development defects is greatly suppressed.

  In the present embodiment, the centripetal acceleration a of the wafer W at the arrival point P is substantially constant while the wafer W is rotating and the cleaning / drying head 100c is moving from the center side to the peripheral side of the wafer W. In addition, the rotational speed ω2 of the wafer W is controlled. Therefore, the centrifugal force acting on the cleaning liquid L2 at the arrival position P is substantially constant in the direction from the central portion to the peripheral portion of the wafer W. For this reason, the drying region D is likely to spread outward as the cleaning / drying head 100c moves. Therefore, the speed at which the drying region D spreads outside compared to the speed at which the cleaning / drying head 100c moves to the peripheral edge of the wafer W can be suppressed (so-called drying delay). That is, resist melt remains on the wafer W due to a delay in drying, and development defects are greatly suppressed.

  In the present embodiment, the cleaning / drying head 100c has a plurality of liquid nozzles h2 to h5 having different opening areas (opening diameters) and arranged in the order of the opening areas, and the liquid nozzles h2 to h5 are switched according to a predetermined condition. This is done in this order (in order of increasing opening area). Therefore, if the flow rate of the cleaning liquid L2 is the same, the discharge speed of the cleaning liquid L2 is sequentially increased by switching from the liquid nozzle h2 having a large opening area to the liquid nozzle h5 having a small opening area. Therefore, the flow rate of the cleaning liquid L2 at the arrival point P can be changed with a simple configuration.

  In the present embodiment, the cleaning / drying head 100c has a plurality of liquid nozzles h2 to h5 whose inclinations with respect to the central axis of the wafer W are different from each other and arranged in the order of inclination, and whose outlets are directed to the surface Wa of the wafer W. The liquid nozzles h2 to h5 are switched in this order (in ascending order of inclination) according to a predetermined condition. Therefore, if the flow rate of the cleaning liquid L2 is the same, the velocity component along the surface Wa of the wafer W in the flow velocity of the cleaning liquid L2 at the arrival point P is switched by switching the liquid nozzle h2 having a small inclination to the liquid nozzle h5 having a large inclination. Gradually increases. Therefore, the speed of the cleaning liquid L2 at the arrival point P can be changed with a simple configuration.

  In the present embodiment, the liquid nozzles h2 to h5 and the wafer W are arranged so that the arrival points P at which the cleaning liquid L2 discharged from the plurality of liquid nozzles h2 to h5 reaches the surface Wa of the wafer W are substantially the same point. The distance from the surface Wa and the inclination of each of the liquid nozzles h2 to h5 are set. Therefore, even if the liquid nozzles h2 to h5 are switched, the cleaning liquid L2 is continuously supplied to the surface Wa of the wafer W without interruption. Therefore, the dissolved resist can be sufficiently removed from the wafer W, and the occurrence of development defects is greatly suppressed.

  In the present embodiment as described above, as shown in FIG. 16, even when the moving speed of the cleaning / drying head 100c is fast, the occurrence of development defects due to drying delay or liquid splashing can be suppressed, and the processing time is greatly shortened. It is possible.

As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to above-described embodiment. For example, as illustrated in FIG. 17A, the cleaning / drying head 100c may include a plurality of gas nozzles h6 _{1 to} h6 ₄ . The gas nozzles h6 _{1 to} h6 ₄ are arranged in this order from the center of the wafer W toward the peripheral edge along the radial direction of the wafer W when viewed from above. The gas nozzles h6 _{1 to} h6 ₄ are arranged corresponding to the liquid nozzles h2 to h5, respectively. The outlets of the gas nozzles h6 _{1 to} h6 ₄ are directed vertically downward. In this case, as the liquid nozzles h2 to h5 from which the cleaning liquid L2 is discharged are sequentially switched, the gas nozzles h6 _{1 to} h6 ₄ are also sequentially switched. Therefore, since the gas nozzle _h6 1 _{~h6 4} from the drying gas G at a position closer to the liquid nozzle h2~h5 cleaning liquid L2 is ejected is discharged, the arrival position of the wafer W of the dry gas G, the cleaning liquid L2 The distance from the arrival position on the wafer W is maintained, and drying delay is suppressed. Therefore, resist melt remains on the wafer W due to a delay in drying, and development defects are greatly suppressed.

  As illustrated in FIG. 17B, the liquid nozzles h <b> 2 to h <b> 5 may be arranged in a line in the tangential direction of the wafer W when viewed from above. In this case, it is easy to set the arrival points P where the cleaning liquid L2 discharged from the plurality of liquid nozzles h2 to h5 reaches the surface Wa of the wafer W to substantially the same point.

  As shown in FIG. 17C, the cleaning / drying head 100c has a plurality of gas nozzles h8 to h11, and the liquid nozzles h2 to h5 and the gas nozzles h8 to h11 are both viewed from above, and the wafer W May be arranged in a line in the tangential direction. The direction in which the front end side (exit side) of the gas nozzles h8 to h11 is inclined is a direction along the tangential direction of the wafer W and from the upstream side to the downstream side in the rotation direction of the wafer W as viewed from above. In FIG. 17C, the set of gas nozzles h8 to h11 is located between the set of gas nozzles h6 and liquid nozzles h2 to h5 in the radial direction of the wafer W. In this case, it is possible to achieve both suppression of drying delay and matching of the arrival point P of the cleaning liquid L2.

  Although not shown, the nozzles h <b> 5 to h <b> 2 may be arranged in this order from the center of the wafer W toward the peripheral edge along the radial direction of the wafer W as viewed from above. That is, the nozzles h2 to h5 may be in the reverse order to the arrangement order of the above embodiment.

  As shown in FIG. 18A, each of the liquid nozzles h2 to h5 may be configured by a collective nozzle that bundles a plurality of small nozzles having a smaller diameter than the liquid nozzles h2 to h5. . As shown in FIG. 18B, the cleaning liquid L2 discharged from these small nozzles reaches substantially the same point. In this case, the flow rate of the cleaning liquid L2 discharged from each small nozzle can be increased by using a small nozzle, and a necessary flow rate of the cleaning liquid L2 can be ensured by bundling a plurality of the small nozzles. it can.

  The cleaning / drying head 100c only needs to have at least one liquid nozzle. In the case of a single liquid nozzle, a mechanism capable of adjusting the flow rate of the cleaning liquid L2 discharged from the liquid nozzle is added, and the arrival point P of the cleaning liquid L2 on the wafer W moves to the periphery of the wafer W. Accordingly, the mechanism may adjust the flow rate to increase the flow rate of the cleaning liquid L2 discharged from the liquid nozzle (see FIG. 19).

As shown in FIG. 20, the wafer W may be cleaned using _two cleaning / drying heads 100c ₁ and 100c ₂ . Specifically, until to form a dry region D as in the embodiment carried out in a single washing and drying head 100c _1. Thereafter, the cleaning liquid L2 is discharged from the liquid nozzles h2 to h5 while moving the two cleaning / drying heads 100c ₁ and 100c ₂ in opposite directions. Switching timings of the liquid nozzles h2 to h5 of the cleaning / drying heads 100c ₁ and 100c ₂ can be set to be the same as shown in FIG. In this case, the cleaning liquid L2 is discharged from the liquid nozzles moving in opposite directions to the surface Wa of the wafer W, respectively. Therefore, a sufficient amount of cleaning liquid L2 can be supplied to the wafer W even for a large-sized wafer W.

  The opening area (opening diameter) of the gas nozzle h6 can be set to be approximately the same as the opening area (opening diameter) of the nozzle h2, for example.

  In the above embodiment, by controlling the discharge speed of the cleaning liquid L2 by switching the liquid nozzles h2 to h5, the difference between the flow rate of the cleaning liquid L2 at the arrival point P and the linear velocity of the wafer W at the arrival point P is within a predetermined range. However, the discharge speed of the cleaning liquid L2 discharged from the liquid nozzle may be constant, and the difference may be within a predetermined range by controlling the number of rotations of the wafer W. Further, by controlling both the discharge speed of the cleaning liquid L2 and the rotational speed of the wafer W, the difference may be within a predetermined range.

  The liquid nozzle and the gas nozzle do not need to be provided in the same cleaning / drying head 100c. That is, these nozzles may be provided in separate heads, and the operation of each head may be controlled.

  DESCRIPTION OF SYMBOLS 1 ... Coating / development apparatus, 20 ... Rotation holding part, 100 ... Surface cleaning / drying part, 100c ... Cleaning / drying head, h2-h5 ... Liquid nozzle, h6 ... Gas nozzle, CU ... Control apparatus, W ... Wafer.

Claims (16)

A rotary drive that rotates the substrate about an axis perpendicular to the surface;
A plurality of liquid nozzles located above the substrate and discharging a cleaning liquid onto the surface of the substrate;
A controller that controls the number of rotations of the substrate, the movement of the liquid nozzle, and the discharge speed of the cleaning liquid discharged from the liquid nozzle;
The plurality of liquid nozzles have different opening areas and are arranged in the order of the opening areas,
At the arrival point where the cleaning liquid discharged from the liquid nozzle reaches the surface of the substrate rotated by the rotation driving unit, the flow direction of the cleaning liquid is in a direction along the linear velocity direction of the substrate. Liquid nozzle is set,
The control unit rotates the substrate by the rotation driving unit and moves the liquid nozzle from the center side to the peripheral side of the substrate,
The rotation speed of the substrate and the discharge speed of the cleaning liquid discharged from the liquid nozzle so that the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is within a predetermined range. Control at least one ,
A substrate cleaning apparatus that discharges a cleaning liquid from the liquid nozzle while switching in order from the liquid nozzle having a large opening area to the liquid nozzle having a small opening area . A plurality of the liquid nozzle, as well as arranged in this order and inclination different inclination from each other with respect to the shaft, the outlet has Tsu suited to the surface of the substrate,
The control unit rotates the substrate by the rotation driving unit and moves the liquid nozzle from the central side toward the peripheral side of the substrate, and in order from the liquid nozzle having a small inclination to the liquid nozzle having a large inclination. The substrate cleaning apparatus according to claim 1 , wherein a cleaning liquid is discharged from the liquid nozzle while switching.   A rotary drive that rotates the substrate about an axis perpendicular to the surface;
  A plurality of liquid nozzles located above the substrate and discharging a cleaning liquid onto the surface of the substrate;
  A controller that controls the number of rotations of the substrate, the movement of the liquid nozzle, and the discharge speed of the cleaning liquid discharged from the liquid nozzle;
  The plurality of liquid nozzles are different from each other in inclination with respect to the axis and are arranged in the order of inclination, and an outlet is directed to the surface of the substrate,
  At the arrival point where the cleaning liquid discharged from the liquid nozzle reaches the surface of the substrate rotated by the rotation driving unit, the flow direction of the cleaning liquid is in a direction along the linear velocity direction of the substrate. Liquid nozzle is set,
  The control unit rotates the substrate by the rotation driving unit and moves the liquid nozzle from the center side to the peripheral side of the substrate,
    The rotation speed of the substrate and the discharge speed of the cleaning liquid discharged from the liquid nozzle so that the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is within a predetermined range. Control at least one,
    A substrate cleaning apparatus that discharges a cleaning liquid from the liquid nozzle while switching in order from the liquid nozzle having a small inclination to the liquid nozzle having a large inclination. The distances between the liquid nozzles and the surface of the substrate, and the liquids so that the arrival points at which the cleaning liquid discharged from the liquid nozzles reaches the surface of the substrate are all substantially the same point. The substrate cleaning apparatus according to claim 2 , wherein an inclination of the nozzle is set. And further comprising at least one gas nozzle located above the substrate and for discharging a dry gas to the surface of the substrate,
Wherein the control unit, so that the gas nozzle is positioned at the center side of the substrate than the nozzle, moving the gas nozzle and the liquid nozzle, a substrate cleaning apparatus according to any one of claims 1 to 4, . The controller controls the number of rotations of the substrate and the cleaning liquid discharged from the liquid nozzle so that the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is ± 25 m / sec. The substrate cleaning apparatus according to any one of claims 1 to 5 , wherein at least one of the discharge speed is controlled.   The substrate cleaning apparatus according to claim 1, wherein the liquid nozzle is configured by a collective nozzle that bundles a plurality of small nozzles having a smaller diameter than the liquid nozzle. And further comprising at least one other liquid nozzle positioned above the substrate and discharging a cleaning liquid onto the surface of the substrate,
At the other arrival point where the cleaning liquid discharged from the other liquid nozzle reaches the surface of the substrate rotated by the rotation driving unit, the flow direction of the cleaning liquid is a direction along the linear velocity direction of the substrate. Is set to be
The control unit rotates the substrate by the rotation driving unit and moves the other liquid nozzle from the center side to the peripheral side of the substrate in a direction different from the liquid nozzle, The number of rotations of the substrate and the discharge speed of the cleaning liquid discharged from the other liquid nozzle so that the difference between the flow rate of the cleaning liquid and the linear velocity of the substrate at the other arrival point is within a predetermined range. The substrate cleaning apparatus according to claim 1, wherein at least one of the two is controlled. While rotating the substrate around an axis perpendicular to the surface, the cleaning liquid is discharged from at least one liquid nozzle located above the substrate to the center of the surface of the substrate, and then the liquid nozzle is The substrate is moved from the center side of the substrate toward the peripheral side, and the arrival point at which the cleaning liquid discharged from the liquid nozzle reaches the surface of the substrate is moved from the center side of the substrate to the peripheral side. A cleaning step of cleaning the surface;
In the washing step,
At the arrival point where the cleaning liquid discharged from the liquid nozzle has reached the surface of the rotating substrate, the flow direction of the cleaning liquid is set to be a direction along the linear velocity direction of the substrate,
While rotating the substrate and moving the liquid nozzle from the central side toward the peripheral side of the substrate, the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is within a predetermined range. So that at least one of the rotational speed of the substrate and the discharge speed of the cleaning liquid discharged from the liquid nozzle is controlled ,
While the substrate is rotated and the liquid nozzle is moved from the center side to the peripheral side of the substrate, the flow rate of the cleaning liquid at the arrival point increases as the liquid nozzle moves toward the peripheral portion of the substrate. discharge rate of the cleaning liquid discharged from the liquid nozzle that are controlled, the substrate cleaning method.   In the cleaning step, the number of rotations of the substrate and the cleaning liquid discharged from the liquid nozzle so that the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is ± 25 m / sec. The substrate cleaning method according to claim 9, wherein at least one of the discharge speed is controlled. In the cleaning step, while the substrate is rotated and the liquid nozzle is moved from the center side to the peripheral side of the substrate, the centripetal acceleration of the substrate at the arrival point is substantially constant. The substrate cleaning method according to claim 9 or 10 , wherein the number of rotations of the substrate is controlled. In the cleaning step, when cleaning the surface of the substrate by discharging a cleaning liquid to the surface of the substrate from a plurality of liquid nozzles having different opening areas and arranged in order of the opening area,
While rotating the substrate and moving the liquid nozzle from the center side toward the peripheral side of the substrate, the cleaning liquid is discharged from the liquid nozzle while switching from the liquid nozzle having a large opening area to the liquid nozzle having a small opening area. The substrate cleaning method according to any one of claims 9 to 11, wherein the substrate is discharged. In the cleaning step, the tilts with respect to the axes are different from each other and arranged in the order of tilts, and the cleaning liquid is discharged to the surface of the substrate from a plurality of liquid nozzles whose outlets are directed to the surface of the substrate. In cleaning the surface, the substrate is rotated and the liquid nozzle is moved from the center side to the peripheral side of the substrate, while the liquid nozzle having a small inclination is switched in the order of the liquid nozzle having a large inclination. ejecting cleaning liquid from the liquid nozzle, a substrate cleaning method according to any one of claims 9-12. In the washing step,
After rotating the substrate and discharging a dry gas from at least one gas nozzle to the center of the surface of the substrate to form a dry region in the center of the surface of the substrate,
While rotating the substrate and moving the liquid nozzle from the central side toward the peripheral side of the substrate, the difference between the flow rate of the cleaning liquid at the arrival point and the linear velocity of the substrate at the arrival point is within a predetermined range. The substrate cleaning method according to any one of claims 9 to 13 , wherein at least one of a rotation speed of the substrate and a discharge speed of the cleaning liquid discharged from the liquid nozzle is controlled so that In the cleaning step, the cleaning liquid is discharged from the plurality of liquid nozzles to the surface of the substrate, and the dry gas is discharged from the plurality of gas nozzles to the surface of the substrate toward the center side from the arrival point of the cleaning liquid. In addition, while moving the plurality of liquid nozzles and the plurality of gas nozzles from the center side to the peripheral side of the substrate, the dry gas is supplied from the gas nozzles while sequentially switching the gas nozzles in accordance with the switching of the plurality of liquid nozzles. The substrate cleaning method according to claim 14 , wherein the substrate is discharged. Claim 9 is recorded a program for executing the method according to the substrate cleaning apparatus in any one of 15, a computer-readable recording medium.

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