JP2018006647A - Substrate liquid processing method and substrate liquid processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of stably suppressing generation of minute particles such as a watermark.SOLUTION: A substrate liquid processing method includes: steps S12 and S13 of supplying processing liquid to a rotating substrate; and a step S14 of forming a rinse liquid film on the rotating substrate by supplying rinse liquid to a central part of the substrate after the steps S12 and S13 of supplying the processing liquid. The method also includes a step S13 of forming a process liquid film in a peripheral part of the substrate in which the process liquid film is interrupted before the step S14 of forming the rinse liquid film.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a technique for performing liquid processing by supplying a processing liquid and a rinsing liquid to a substrate.

  In order to perform liquid processing such as chemical processing and rinsing processing on a substrate such as a semiconductor wafer, the substrate held in a horizontal posture is rotated around a vertical axis, and a DHF (Diluted HydroFluoric) is applied to the vicinity of the center of the processing surface of the substrate. A method of supplying a treatment liquid such as acid) or a rinse liquid such as DIW (DeIonized Water) is generally employed (see, for example, Patent Document 1). In this method, the treatment liquid and the rinse liquid supplied near the center of the substrate are diffused by centrifugal force, and the diffused treatment liquid and the rinse liquid cover the treatment surface of the substrate to perform the chemical liquid treatment and the rinse treatment.

  When performing the above chemical processing, the flow rate of the processing liquid and the rotation speed of the substrate when supplying the processing liquid are set for the purpose of uniformly processing the entire substrate.

  It has been found that as the circuit formed on the surface of a semiconductor wafer or the like is miniaturized, minute particles become a problem. In recent years, it has become possible to measure minute particles, so particles that have not been seen until now have become visible. The inventor of the present invention has found that such particles are caused by the watermark and are likely to occur at the peripheral edge of the substrate.

JP 2009-59895 A

  The present invention provides a technique capable of stably suppressing the generation of minute particles such as watermarks.

  According to one embodiment of the present invention, a rinsing liquid is supplied to a central portion of a rotating substrate after the step of supplying the processing liquid to the central portion of the rotating substrate and the step of supplying the processing liquid. And a step of forming a liquid film of the treatment liquid on the peripheral portion of the substrate where the liquid film of the treatment liquid is interrupted before the step of forming the liquid film of the rinsing liquid. The present invention relates to a liquid processing method.

  According to another aspect of the present invention, a substrate holding unit that holds and rotates a substrate, a processing liquid supply unit that supplies a processing liquid to the substrate held by the substrate holding unit, and a processing liquid is supplied by the processing liquid supply unit. After that, the rinsing liquid is supplied to the substrate held by the substrate holding unit, and the rinsing liquid supply unit that forms a liquid film of the rinsing liquid on the substrate, and the substrate holding unit, the processing liquid supply unit, and the rinsing liquid supply unit are controlled. And a control unit that forms a liquid film of the processing liquid on a peripheral portion of the substrate where the liquid film of the processing liquid is interrupted before forming the liquid film of the rinsing liquid. .

  According to the present invention, generation of fine particles such as a watermark can be stably suppressed.

FIG. 1 is a plan view showing an outline of a substrate processing system including a processing unit according to an embodiment of the present invention. FIG. 2 is a longitudinal side view showing an outline of the processing unit. FIG. 3 is a diagram illustrating a specific configuration of the processing unit and the control unit. FIG. 4 is a cross-sectional view showing an example in which the liquid processing fluid forms a liquid film over only a part of the processing surface of the wafer. FIG. 5 is a cross-sectional view showing an example in which the liquid processing fluid forms a liquid film over the entire processing surface of the wafer. FIG. 6 is a flowchart of the substrate liquid processing method. FIG. 7 is a graph showing the relationship among the number of wafer rotations, time, and liquid supply flow rate in the first chemical liquid processing step, the second chemical liquid processing step, and the rinse processing step. FIG. 8 is a graph showing the relationship among the number of wafer rotations, time, and liquid supply flow rate in the first chemical liquid processing step, the second chemical liquid processing step, and the rinse processing step.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  First, a typical example of a substrate processing system to which the present invention can be applied will be described.

  FIG. 1 is a diagram showing a schematic configuration of a substrate processing system according to the present embodiment. In the following, in order to clarify the positional relationship, the X axis, the Y axis, and the Z axis that are orthogonal to each other are defined, and the positive direction of the Z axis is the vertically upward direction.

  As shown in FIG. 1, the substrate processing system 1 includes a carry-in / out station 2 and a processing station 3. The carry-in / out station 2 and the processing station 3 are provided adjacent to each other.

  The carry-in / out station 2 includes a carrier placement unit 11 and a transport unit 12. A plurality of carriers C that accommodate a plurality of substrates, in this embodiment a semiconductor wafer (hereinafter referred to as a wafer W) in a horizontal state, are placed on the carrier placement unit 11.

  The transport unit 12 is provided adjacent to the carrier placement unit 11 and includes a substrate transport device 13 and a delivery unit 14 inside. The substrate transfer device 13 includes a wafer holding mechanism that holds the wafer W. Further, the substrate transfer device 13 can move in the horizontal direction and the vertical direction and can turn around the vertical axis, and transfers the wafer W between the carrier C and the delivery unit 14 using the wafer holding mechanism. Do.

  The processing station 3 is provided adjacent to the transfer unit 12. The processing station 3 includes a transport unit 15 and a plurality of processing units 16. The plurality of processing units 16 are provided side by side on the transport unit 15.

  The transport unit 15 includes a substrate transport device 17 inside. The substrate transfer device 17 includes a wafer holding mechanism that holds the wafer W. Further, the substrate transfer device 17 can move in the horizontal direction and the vertical direction and can turn around the vertical axis, and transfers the wafer W between the delivery unit 14 and the processing unit 16 using a wafer holding mechanism. I do.

  The processing unit 16 performs predetermined substrate processing on the wafer W transferred by the substrate transfer device 17.

  Further, the substrate processing system 1 includes a control device 4. The control device 4 is a computer, for example, and includes a control unit 18 and a storage unit 19. The storage unit 19 stores a program for controlling various processes executed in the substrate processing system 1. The control unit 18 controls the operation of the substrate processing system 1 by reading and executing the program stored in the storage unit 19.

  Such a program may be recorded on a computer-readable storage medium, and may be installed in the storage unit 19 of the control device 4 from the storage medium. Examples of the computer-readable storage medium include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

  In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 of the loading / unloading station 2 takes out the wafer W from the carrier C placed on the carrier placement unit 11 and receives the taken-out wafer W. Place on the transfer section 14. The wafer W placed on the delivery unit 14 is taken out from the delivery unit 14 by the substrate transfer device 17 of the processing station 3 and carried into the processing unit 16.

  The wafer W loaded into the processing unit 16 is processed by the processing unit 16, then unloaded from the processing unit 16 by the substrate transfer device 17, and placed on the delivery unit 14. Then, the processed wafer W placed on the delivery unit 14 is returned to the carrier C of the carrier platform 11 by the substrate transfer device 13.

  Next, a typical example of the processing unit 16 will be described with reference to FIG.

  As shown in FIG. 2, the processing unit 16 includes a chamber 20, a substrate holding mechanism 30, a processing fluid supply unit 40, and a recovery cup 50.

  The chamber 20 accommodates the substrate holding mechanism 30, the processing fluid supply unit 40, and the recovery cup 50. An FFU (Fan Filter Unit) 21 is provided on the ceiling of the chamber 20. The FFU 21 forms a down flow in the chamber 20.

  The substrate holding mechanism 30 includes a holding unit 31, a support unit 32, and a driving unit 33. The holding unit 31 holds the wafer W horizontally. The support | pillar part 32 is a member extended in a perpendicular direction, a base end part is rotatably supported by the drive part 33, and supports the holding | maintenance part 31 horizontally in a front-end | tip part. The drive unit 33 rotates the column unit 32 around the vertical axis. The substrate holding mechanism 30 rotates the support unit 32 by rotating the support unit 32 using the drive unit 33, thereby rotating the wafer W held by the support unit 31. .

  The processing fluid supply unit 40 supplies a processing fluid to the wafer W. The processing fluid supply unit 40 is connected to a processing fluid supply source 70.

  The collection cup 50 is disposed so as to surround the holding unit 31, and collects the processing liquid scattered from the wafer W by the rotation of the holding unit 31. A drain port 51 is formed at the bottom of the recovery cup 50, and the processing liquid collected by the recovery cup 50 is discharged from the drain port 51 to the outside of the processing unit 16. Further, an exhaust port 52 for discharging the gas supplied from the FFU 21 to the outside of the processing unit 16 is formed at the bottom of the recovery cup 50.

  The processing unit 16 and the control unit 18 whose schematic configuration has been described above constitute at least a part of the substrate liquid processing apparatus according to the embodiment of the present invention. For example, the above-described holding unit 31, support unit 32, and driving unit 33 function as a substrate holding unit that holds and rotates the wafer W having an oxide film formed on the processing surface. The processing fluid supply source 70 and the processing fluid supply unit 40 described above function as a processing liquid supply unit that supplies DHF, which is a processing liquid for removing the oxide film, to the wafer W held by the substrate holding unit. Similarly, the processing fluid supply source 70 and the processing fluid supply unit 40 supply DIW, which is a rinsing liquid, after the DHF is supplied by the processing liquid supply unit to the wafer W held by the substrate holding unit. It also functions as a rinsing liquid supply unit for forming a DIW liquid film on the processed surface. And the control part 18 controls these board | substrate holding | maintenance parts, a process liquid supply part, and a rinse liquid supply part.

  Hereinafter, detailed configurations of the processing unit 16 and the control unit 18 will be described with reference to FIG.

  FIG. 3 is a diagram illustrating a specific configuration of the processing unit 16 and the control unit 18.

  The processing unit 16 includes a recovery cup 50 and a processing fluid supply unit 40 provided in the chamber 20 illustrated in FIG. 2, and processes the wafer W loaded into the chamber 20. As shown in FIG. 1, the plurality of processing units 16 provided on both sides of the transport unit 15 are arranged with a loading / unloading port (not shown) facing the transport unit 15 side. FIG. 3 shows the directions in each processing unit 16 using the X ′ axis, Y ′ axis, and Z ′ axis. With respect to the directions of these axes, the direction in which the loading / unloading port is provided is defined as the front side in the Y′-axis direction, the X ′ axis and the Z ′ axis perpendicular to the Y ′ axis are defined, and the positive direction of the Z ′ axis is particularly defined. The vertical upward direction was used.

  As shown in FIG. 3, the processing fluid supply unit 40 includes a nozzle head 41 having a first nozzle 400, a nozzle arm 42 to which the nozzle head 41 is attached at the tip, and a base end of the nozzle arm 42. And a rotation drive unit 43 to be supported. The rotation drive unit 43 can rotate the nozzle arm 42 in the horizontal direction with the base end portion of the nozzle arm 42 as a rotation axis. The first nozzle 400 is moved between a processing position set on the upper side of the central portion of the wafer W and a retracted position retracted to the side of the recovery cup 50 according to the rotation of the nozzle arm 42. When DHF or DIW is supplied to the wafer W to perform chemical processing or rinsing processing, the first nozzle 400 is disposed at the processing position. On the other hand, when such chemical processing or rinsing processing is not performed, the first nozzle 400 is disposed at the retracted position.

  The rotation drive unit 43 can further move the nozzle arm 42 up and down, and an upper height position when rotating the nozzle arm 42 and a lower height position for supplying DHF or DIW to the wafer W. The nozzle arm 42 and the first nozzle 400 can be moved in the vertical direction.

  A rinse liquid supply path 711 and a DHF supply path 713 are connected to the first nozzle 400. The rinse liquid supply path 711 and the DHF supply path 713 are respectively connected to the DIW supply source 701 and the DHF supply source 702 that constitute the processing fluid supply source 70 described above. The DIW supply source 701 includes a storage unit that stores DIW, a pump for supplying DIW, a flow rate adjustment valve, and the like. Similarly, the DHF supply source 702 includes a storage unit that stores DHF, a pump for supplying DHF, a flow rate adjustment valve, and the like. The DIW supply source 701 and the DHF supply source 702 are controlled by a control signal from the control unit 18. In response to this control signal, DIW is supplied from the DIW supply source 701 to the first nozzle 400 via the rinse liquid supply path 711 and the supply pipe of the nozzle arm 42, and from the DHF supply source 702 to the DHF supply path 713 and the nozzle arm. DHF is supplied to the first nozzle 400 via the supply pipe 42.

  The control unit 18 also sends a control signal to the drive unit 33. The drive unit 33 is controlled by a control signal from the control unit 18, and the number of rotations around the vertical axis of the support column 32 is adjusted according to this control signal and is held by the holding unit 31 fixed to the support column 32. The number of rotations of the wafer W can also be changed.

<Preventing the generation of minute particles>
The chemical process for supplying DHF and the rinsing process for supplying DIW are continuously performed toward the center of the rotating wafer W. Usually, the supply amount of the chemical solution or the number of rotations of the substrate is set to a condition capable of uniformly processing the surface of the wafer W. Under such conditions, the present inventor exposes the peripheral portion of the wafer W that should be coated with the liquid when the liquid supplied to the hydrophobic processing surface of the wafer W is switched from DHF to DIW. I found And it was found that this induces minute particles such as watermarks.

  The present inventors pay attention to the liquid covering property to the peripheral portion of the wafer W when the liquid supplied to the hydrophobic processing surface of the wafer W is switched from DHF to DIW, and by improving the liquid covering property, We obtained new knowledge that minute particles such as watermarks can be stably reduced. Specifically, in the final stage of the chemical processing (for example, about several seconds before the chemical processing is completed), the number of rotations of the wafer W and the supply amount of DHF are increased, and the entire processing surface of the wafer W is covered with the DHF liquid film. Thus, by starting the supply of DIW, generation of minute watermarks can be effectively suppressed. That is, the liquid coating on the processing surface of the wafer W is improved at the stage where the chemical processing is performed, and the liquid coating on the processing surface is performed by shifting from the chemical processing to the rinsing processing in a state where the liquid covering is sufficiently improved. It is possible to remarkably shorten or eliminate the time when the property is incomplete, and to suppress the generation of minute watermarks very effectively.

  Based on the above consideration, the control unit 18 shown in FIG. 3 performs the following control in order to prevent the generation of minute particles in the liquid treatment process using DHF and DIW.

  That is, the control unit 18 controls the driving unit 33 constituting the substrate holding unit and the DHF supply source 702 constituting the processing liquid supply unit to supply DHF to the central portion of the wafer W and to supply the DHF liquid over the entire processing surface. A film is formed. The controller 18 controls the drive unit 33 and the DHF supply source 702 so that the DHF liquid film is formed on the peripheral edge of the wafer W where the DHF liquid film is interrupted before the DIW liquid film is formed. . Then, the control unit 18 controls the DIW supply source 701 and the drive unit 33 constituting the rinse liquid supply unit to supply DIW to the central portion of the wafer W, and a DHF liquid film is formed over the entire processing surface. In this state, supply of DIW to the wafer W is started.

  FIG. 4 is a cross-sectional view showing an example in which the liquid processing fluid L forms a liquid film over only a part of the processing surface Ws of the wafer W. FIG. 5 is a cross-sectional view showing an example in which the liquid processing fluid L forms a liquid film over the entire processing surface Ws of the wafer W. The liquid processing fluid L shown in FIGS. 4 and 5 representatively represents the above-described DHF and DIW.

  When the liquid processing fluid L is supplied from the first nozzle 400 to the processing surface Ws of the wafer W that rotates about the rotation axis Aw, the liquid processing fluid L rotates together with the wafer W, and the outside of the wafer W in the radial direction. Under the influence of the centrifugal force acting toward the surface, the wafer W expands toward the outer peripheral portion Wp.

  For example, when the number of rotations of the wafer W is not sufficiently large or when the supply amount of the liquid processing fluid L to the wafer W is not sufficiently large, as shown in FIG. Cannot be extended to the outer peripheral portion Wp of the wafer W, and the liquid processing fluid L forms a liquid film only in a partial range centering on the central portion of the wafer W. On the other hand, when the rotation speed of the wafer W is sufficiently large or when the supply amount of the liquid processing fluid L to the wafer W is sufficiently large, as shown in FIG. 5, the liquid film formed by the liquid processing fluid L is the wafer. A liquid film of the liquid processing fluid L is formed over the entire processing surface Ws of the wafer W, extending to the outer peripheral portion Wp of W.

  The excess liquid processing fluid L that does not contribute to the formation of the liquid film is torn off from the liquid film and becomes droplets. In particular, as shown in FIG. 4, in a state where the liquid film of the liquid processing fluid L is formed only in a partial range of the processing surface Ws of the wafer W, the droplets of the liquid processing fluid L that are torn off from the liquid film The wafer W is shaken off after flowing to the outer peripheral portion Wp side. However, not all of the liquid droplets that have been separated from the liquid film and have flowed to the outer peripheral portion Wp side are shaken off from the wafer W, and some liquid processing fluid L remains in the form of droplets on the outer peripheral portion Wp of the wafer W. May end up. In particular, when the liquid processing fluid L existing as droplets on the outer peripheral portion Wp of the wafer W is DIW, generation of minute particles such as a watermark is induced. In the substrate liquid processing apparatus and the substrate liquid processing method of the present embodiment, in order to suppress the generation of such fine particles, a DHF liquid film is formed over the entire processing surface Ws of the wafer W, and then the processing surface Ws. Supply of DIW to the wafer W is started in a state where a liquid film of DHF is formed over the entire area.

  Hereinafter, the substrate liquid processing method in the present embodiment will be described in detail. The substrate liquid processing method according to the present embodiment supplies DIW to the central portion of the rotating wafer W after supplying the DHF to the central portion of the rotating wafer W and supplying the DHF. Forming a liquid film of DIW. Further, the substrate liquid processing method includes a step of forming a DHF liquid film on the peripheral portion of the wafer W where the DHF liquid film is interrupted before the step of forming the DIW liquid film.

  FIG. 6 is a flowchart of the substrate liquid processing method. In the substrate solution processing method of the present embodiment, the substrate preparation step S11, the first chemical solution treatment step S12, the second chemical solution treatment step S13, and the rinse treatment step S14 are sequentially performed.

  The substrate preparation step S11 is a step of preparing a wafer W having an oxide film formed on the processing surface. A wafer W on which an oxide film such as a natural oxide is formed on the processing surface is transferred in the transfer unit 15 by the substrate transfer device 17 shown in FIG. 1, and is processed in the processing unit 16 that performs liquid processing using DHF and DIW. Then, the wafer W is carried in via the loading / unloading port, and the wafer W is held by the holding unit 31. Note that after the wafer W is transferred to the holding pins 311, the substrate transfer device 17 leaves the processing unit 16.

  Each of the first chemical solution processing step S12 and the second chemical solution processing step S13 is a step of supplying DHF for removing the oxide film to the rotating wafer W. In the first chemical liquid processing step S12, a DHF liquid film is formed only over a part (particularly the central part) of the processing surface Ws of the wafer W (see FIG. 4). On the other hand, in the second chemical processing step S13, a DHF liquid film is formed over the entire processing surface Ws of the wafer W (see FIG. 5).

  Since the characteristics of the processing surface Ws of the wafer W change as the oxide removal processing by DHF progresses, the state of the DHF liquid film on the processing surface Ws in the first chemical processing step S12 may also change. Therefore, when the wafer W is rotated at the first rotational speed in the first chemical liquid processing step S12, it is possible to form a DHF liquid film over the entire processing surface Ws of the wafer W at the beginning of the supply of DHF. Even if there is, when the oxide film is etched by DHF, the DHF liquid film is interrupted on the processing surface Ws, and the DHF liquid film is not formed on the peripheral edge of the wafer W. Therefore, in the present embodiment, a DHF liquid film is formed in the peripheral portion of the wafer W where the DHF liquid film is interrupted in the second chemical liquid processing step S13. As described above, in the present embodiment, the step of supplying DHF to the wafer W rotating at the first rotational speed includes the step of forming a liquid film of DHF over the entire processing surface Ws of the wafer W, and the processing surface of the wafer W. And a step of forming a DHF liquid film only over a partial region of Ws (particularly the central portion).

  Since the chemical processing conditions are set so that the processing surface Ws of the wafer W is processed uniformly, the DHF liquid film may not be formed on the processing surface Ws of the wafer W in the first chemical processing step S12. is there. Also in this case, in the second chemical liquid processing step S13, a DHF liquid film is formed over the entire processing surface Ws of the wafer W, and a DHF liquid film is formed on the periphery of the wafer W where the DHF liquid film is interrupted. Thus, the same effect can be obtained. In consideration of the uniformity of the chemical treatment, the number of rotations of the wafer W may not be increased. For example, if the number of rotations of the wafer W is increased too much, there is a concern that the DHF once shaken off from the wafer W will be bounced back by the surrounding collection cup 50 and adhere to the wafer W again. The wafer W is contaminated by DHF.

  The rinse treatment step S14 is performed after the second chemical solution treatment step S13 for supplying DHF, supplying DIW to the rotating wafer W, and forming a DIW liquid film on the processing surface Ws of the wafer W. is there. The rinse treatment step S14 is performed immediately after the second chemical solution treatment step S13 described above, and the supply of DIW to the wafer W is started in a state where the DHF liquid film is formed over the entire processing surface Ws of the wafer W. . Even after the DIW supply to the wafer W is started, the supply amount of DIW to the wafer W and the rotation speed of the wafer W are adjusted so that the liquid film is formed over the entire processing surface Ws. Is done. Therefore, immediately after the start of the DIW supply to the wafer W, a liquid film is formed on the processing surface Ws by the mixed liquid of DHF and DIW, but the DIW in the liquid film gradually gradually as time passes from the start of the DIW supply. The ratio increases and finally a liquid film is formed only by DIW.

  As described above, before the DIW supply is started, a liquid film is formed over the entire processing surface Ws of the wafer W by DHF, and the DIW supply is started in a state where the DHF liquid film is formed over the entire processing surface Ws. Is done. Accordingly, it is possible to avoid the state shown in FIG. 4 in which the liquid film of DIW is formed only on a part of the processing surface Ws of the wafer W and the droplets of DIW exist on the outer peripheral portion Wp of the wafer W. it can. As described above, fine particles such as watermarks generated on the outer peripheral portion Wp of the wafer W are torn off from the liquid film mainly in a state where the liquid film of DIW is formed only on a part of the processing surface Ws of the wafer W. This is because the DIW droplets exist on the outer peripheral portion Wp of the wafer W. Therefore, by avoiding the state in which the liquid film of DIW is formed only on a part of the processing surface Ws of the wafer W as described above, so that the DIW droplet does not exist on the outer peripheral portion Wp of the wafer W, Generation of minute particles such as watermarks on the outer peripheral portion Wp of the wafer W can be prevented.

  Next, a method of forming a liquid film over the entire processing surface Ws of the wafer W by adjusting the rotation speed of the wafer W, which is a modification of the present embodiment, will be described.

  FIG. 7 is a graph showing the relationship among the wafer rotation speed, time, and liquid supply flow rate in the first chemical liquid processing step S12, the second chemical liquid processing step S13, and the rinse processing step S14. In FIG. 7, the horizontal axis represents time (seconds), the left vertical axis represents the number of revolutions of the wafer W (rpm: revolutions per minute), and the right vertical axis represents the liquid supply flow rates of DHF and DWI to the wafer W ( ml / min). A solid line indicated by reference sign “R1” indicates a relationship between “time” and “the number of rotations of the wafer W” according to the present embodiment. A dotted line indicated by a symbol “R2” indicates a relationship between “time” and “the number of rotations of the wafer W” according to the comparative example. The alternate long and short dash line indicated by the symbol “F1” indicates the relationship between “time” and “DHF liquid supply amount”, and the two-dot chain line indicated by the symbol “F2” indicates the relationship between “time” and “DIW liquid supply amount”. Indicates.

  The lines indicated by the symbols “F1” and “F2” are common in the present embodiment and the comparative example, and the supply amount of DHF and the supply amount of DIW to the wafer W are the same in the present embodiment and the comparative example. . That is, in both the substrate liquid processing method according to the present embodiment and the substrate liquid processing method according to the comparative example, the amount of DHF supplied to the wafer W (see reference numeral “F1”) is constant regardless of the time, and the wafer W The DIW supply amount (see reference sign “F2”) is constant regardless of the time, and the DHF supply amount and the DIW supply amount are the same.

  In the comparative example represented by the symbol “R2”, the rotational speed of the wafer W rotates at a constant rate at the first rotational speed N1 in both the first chemical liquid processing step S12 and the second chemical liquid processing step S13. While DHF is supplied to the wafer W, a liquid film of DHF is formed only on a part of the processing surface Ws of the wafer W as shown in FIG. When the supply of DHF to the wafer W is completed and the supply of DIW is started, the rotational speed of the wafer W gradually increases, and the rotational speed of the wafer W is increased from the first rotational speed N1 to the second rotational speed N2. Will be increased.

  In this comparative example, while the rotational speed of the wafer W is increased from the first rotational speed N1 to the second rotational speed N2, DIW is supplied to the wafer W, while on the processing surface Ws of the wafer W. There is a period in which the liquid film to be formed does not exist in the outer peripheral portion Wp. Therefore, during the period in which the rotation speed of the wafer W is increased from the first rotation speed N1 to the second rotation speed N2, while the liquid film is formed only on a part of the processing surface Ws of the wafer W, the liquid film A droplet containing DIW that has been torn off may be present on the outer periphery Wp. As described above, minute particles such as watermarks generated on the outer peripheral portion Wp of the wafer W are caused by the presence of DIW droplets on the outer peripheral portion Wp of the wafer W. Is triggered.

  On the other hand, in the present embodiment represented by the symbol “R1”, the step of supplying DHF includes the first chemical processing step S12 in which DHF is supplied to the wafer W rotating at the first rotational speed N1, and the first rotational speed. And a second chemical processing step S13 in which DHF is supplied to the wafer W rotating at a second rotation speed N2 that is faster than N1. In the first chemical processing step S12, the DHF supplied to the wafer W rotating at the first rotational speed N1 forms a liquid film at the center of the processing surface Ws of the wafer W, and the DHF liquid is formed at the peripheral portion of the wafer W. The membrane is broken. On the other hand, in the second chemical liquid processing step S13, the DHF is supplied to the wafer W rotating at the second rotational speed N2 that is faster than the first rotational speed N1, so that the wafer is processed before the rinse processing step S14 for supplying DIW. A DHF liquid film is formed over the entire W processing surface Ws. More specifically, in the second chemical liquid processing step S13, the rotation speed of the wafer W is proportionally increased from the first rotation speed N1 to the second rotation speed N2, and then the rotation speed of the wafer W is increased to the second rotation speed. N2 is maintained. Thereby, a DHF liquid film is formed over the entire processing surface Ws of the wafer W. In the rinsing process S14, the rotational speed of the wafer W is maintained at the second rotational speed N2, and DIW is supplied to the wafer W that rotates at the second rotational speed N2 that is faster than the first rotational speed N1. Thus, DIW is supplied to the wafer W in a state where a liquid film is formed over the entire processing surface Ws.

  As described above, the DHF liquid film is formed over the entire processing surface Ws of the wafer W by adjusting the rotation speed of the wafer W in the previous stage of the rinsing processing step S14. The rotation speed of the wafer W is adjusted so that a liquid film is formed over the entire region. Accordingly, the liquid film containing DIW can be prevented from being formed only on a part of the processing surface Ws of the wafer W, and the period during which droplets containing DIW can exist in the outer peripheral portion Wp can be avoided. Further, the generation of minute particles such as watermarks in the outer peripheral portion Wp can be suppressed.

  In the example shown in FIG. 7 described above, the rotational speed of the wafer W is increased to the second rotational speed N2 in the second chemical liquid processing step S13, but a DHF liquid film is formed over the entire processing surface Ws of the wafer W. If possible, the rotation speed of the wafer W in the second chemical liquid processing step S13 is not limited to the second rotation speed N2. However, in the final stage of the second chemical solution processing step S13, the number of rotations of the wafer W is increased to the same number of rotations as the number of rotations of the wafer W obtained in the rinse processing step S14. The transition to S14 can be easily performed.

  Next, a method for forming a liquid film over the entire processing surface Ws of the wafer W by adjusting the liquid supply amount will be described.

  FIG. 8 is a graph showing the relationship between the number of wafer rotations, time, and liquid supply flow rate in the first chemical liquid processing step S12, the second chemical liquid processing step S13, and the rinse processing step S14. In FIG. 8, the horizontal axis represents time (seconds), the left vertical axis represents the rotation speed (rpm) of the wafer W, and the right vertical axis represents the liquid supply flow rates (ml / min) of DHF and DWI to the wafer W. Indicates. A solid line indicated by reference sign “R1” indicates a relationship between “time” and “the number of rotations of the wafer W” according to the present embodiment. The alternate long and short dash line indicated by the symbol “F1” indicates the relationship between “time” and “DHF liquid supply amount”, and the two-dot chain line indicated by the symbol “F2” indicates the relationship between “time” and “DIW liquid supply amount”. Indicates.

  In the example shown in FIG. 8, the process of supplying DHF includes the first chemical processing step S12 in which the DHF of the first supply amount P1 is supplied to the wafer W, and the DHF of the second supply amount P2 that is larger than the first supply amount P1. Has a second chemical processing step S13 to be supplied to the wafer W. In the first chemical liquid processing step S12, the DHF supplied to the wafer W with the first supply amount P1 forms a liquid film at the center of the processing surface Ws of the wafer W, and the liquid film of the processing liquid at the peripheral portion of the wafer W. Is interrupted. On the other hand, in the second chemical liquid processing step S13, a supply amount of DHF larger than the first supply amount P1 is supplied to the wafer W, whereby a DHF liquid film is formed over the entire processing surface Ws of the wafer W. More specifically, in the second chemical treatment step S13, the supply amount of DHF is proportionally increased from the first supply amount P1 to the second supply amount P2, and then the supply amount of DHF is changed to the second supply amount P2. Maintained. Thereby, a DHF liquid film is formed over the entire processing surface Ws of the wafer W. During the first chemical solution processing step S12 and the second chemical solution processing step S13, the wafer W is rotated at the first rotation speed N1, and the rotation speed of the wafer W is kept constant.

  In the rinsing process S14, the rotation speed of the wafer W is increased from the first rotation speed N1 to the second rotation speed N2, while the supply amount of DIW is started at the second supply amount P2, and then the first rotation speed N1 is reached. The supply amount is reduced to P1. Thus, while the rotation speed of the wafer W is increased from the first rotation speed N1 to the second rotation speed N2, and the supply amount of DIW is reduced from the second supply amount P2 to the first supply amount P1, the processing of the wafer W is performed. The state in which the liquid film is formed over the entire surface Ws is maintained. In the rinsing process S14, after the rotation speed of the wafer W reaches the second rotation speed N2, the rotation speed of the wafer W is maintained at the second rotation speed N2, and the supply amount of DIW is set to the first supply amount P1. After reaching, the supply amount of DIW is maintained at the first supply amount P1. As described above, the liquid film is formed over the entire processing surface Ws of the wafer W while the rotation speed of the wafer W is maintained at the second rotation speed N2 and the supply amount of DIW is maintained at the first supply amount P1. Maintained.

  As described above, the DHF supply amount is adjusted to form the DHF liquid film over the entire processing surface Ws of the wafer W in the previous stage of the rinsing processing step S14, and the entire processing surface Ws is also formed during the rinsing processing step S14. The supply amount of DIW and the rotation speed of the wafer W are adjusted so that the liquid film is formed over the entire area. Accordingly, the liquid film containing DIW can be prevented from being formed only on a part of the processing surface Ws of the wafer W, and the period during which droplets containing DIW can exist in the outer peripheral portion Wp can be avoided. Further, the generation of minute particles such as watermarks on the outer peripheral portion Wp of the wafer W can be suppressed.

  In the example shown in FIG. 8 described above, the rotation speed of the wafer W is maintained constant during the first chemical liquid processing step S12 and the second chemical liquid processing step S13 in which DHF is supplied to the wafer W. The rotation speed of W does not necessarily have to be constant. For example, when the rotation speed of the wafer W is the first rotation speed N1 and the supply amount of DHF is the third supply amount (however, the relationship of “first supply amount P1 <third supply amount <second supply amount P2” is satisfied). The DHF liquid film may not be formed over the entire processing surface Ws of the wafer W. Further, when the rotation speed of the wafer W is the third rotation speed (provided that the relationship “first rotation speed N1 <third rotation speed <second rotation speed N2”) and the supply amount of DHF is the first supply amount P1, The DHF liquid film may not be formed over the entire processing surface Ws of the wafer W. On the other hand, when the rotation speed of the wafer W is the third rotation speed and the supply amount of DHF is the third supply amount, a DHF liquid film may be formed over the entire processing surface Ws of the wafer W in some cases. In this case, the degree of increase in the amount of DHF supplied in the second chemical liquid processing step S13 can be suppressed, and the consumption of DHF can be saved. Further, in the second chemical liquid processing step S13, the rotational speed of the wafer W is adjusted to a rotational speed faster than the first rotational speed N1, so that the rotational speed of the wafer W can be targeted in a shorter time in the subsequent rinsing process S14. The rotation speed can be adjusted to the second rotation speed N2. From the viewpoint of smoothly transitioning from the second chemical processing step S13 to the rinsing processing step S14, the final target rotational speed of the wafer W in the second chemical processing step S13 is set as the target rotation of the wafer W in the rinsing processing step S14. The number is preferably the same.

  In the example shown in FIG. 8 described above, the control unit 18 shown in FIG. 3 controls the DHF supply source 702 to increase the amount of DHF supplied to the wafer W, but assists the supply of DHF to the wafer W. Auxiliary means may be further provided. That is, a DHF supply auxiliary unit is provided separately from the above-described DHF supply source 702, and the DHF supply auxiliary unit additionally supplies DHF to the wafer W under the control of the control unit 18, so that the DHF for the wafer W is provided. The supply amount may be increased. In addition, the specific structure of this DHF supply auxiliary | assistant part is not specifically limited. For example, the DHF supply auxiliary unit may share the supply pipe of the nozzle arm 42 and the first nozzle 400 shown in FIG. 3 with the DHF supply source 702, or may be a dedicated dedicated separate from the nozzle arm 42 and the first nozzle 400. You may have a supply pipe and a nozzle.

  As described above, according to the substrate liquid processing method and the substrate liquid processing apparatus of this embodiment and the modification, the DIW liquid film is formed on the wafer W while the DHF liquid film is formed over the entire processing surface Ws of the wafer W. Supply is started. Thereby, it is possible to prevent a period during which a droplet containing DIW may exist on the outer peripheral portion Wp of the wafer W, and to stably suppress generation of minute particles such as a watermark.

  Note that the present invention is not limited to the above-described embodiments and modifications, and various aspects to which various modifications that can be conceived by those skilled in the art can be included in the scope of the present invention. The effect produced by is not limited to the above-mentioned matters. Therefore, various additions, modifications, and partial deletions can be made to each element described in the claims and the specification without departing from the technical idea and spirit of the present invention.

  For example, in the above-described embodiment, an example in which DHF is used as the processing liquid and DIW is used as the rinsing liquid has been described, but the processing liquid and the rinsing liquid are not particularly limited. A solution containing hydrofluoric acid can be suitably used as the treatment liquid. Any liquid necessary for a desired chemical treatment such as etching removal of an oxide film can be used as a treatment liquid, and any liquid that can properly wash out such a treatment liquid is used as a rinse liquid. It is possible.

  Further, the composition of the wafer W is not particularly limited, and the wafer W is typically composed of high-purity silicon. In particular, in the substrate liquid processing method and the substrate liquid processing apparatus described above, the wafer W in which the contact angle of the processing surface Ws from which the oxide film has been removed by the processing liquid is larger than the contact angle of the processing surface Ws on which the oxide film is formed. However, it can be suitably applied.

18 Control Unit 30 Substrate Holding Mechanism 40 Processing Fluid Supply Unit W Wafer

Claims (11)

Supplying a processing liquid to the center of the rotating substrate;
After the step of supplying the treatment liquid, supplying a rinsing liquid to the center of the rotating substrate, and forming a liquid film of the rinsing liquid on the substrate,
A substrate liquid processing method comprising a step of forming a liquid film of the processing liquid on a peripheral edge of the substrate where the liquid film of the processing liquid is interrupted before the step of forming the liquid film of the rinsing liquid. In the step of supplying the processing liquid, the processing liquid is supplied to the substrate rotating at a first rotational speed,
In the step of forming a liquid film of the processing liquid on the peripheral portion, the rinsing liquid is supplied by supplying the processing liquid to the substrate that rotates at a second rotational speed that is faster than the first rotational speed. The substrate liquid processing method according to claim 1, wherein a liquid film of the processing liquid is formed before the process.   The process liquid supplied to the substrate rotating at the first rotational speed forms a liquid film at the center of the substrate, and the liquid film of the process liquid is interrupted at the peripheral edge. Substrate liquid processing method.   4. The substrate liquid processing method according to claim 2, wherein the first number of rotations is a number of rotations capable of forming a liquid film of the processing liquid over the entire processing surface of the substrate.   5. The substrate liquid processing according to claim 2, wherein in the step of supplying the rinsing liquid, the rinsing liquid is supplied to the substrate that rotates at a second rotational speed that is faster than the first rotational speed. Method. The step of supplying the processing liquid includes a step of supplying a first supply amount of the processing liquid to the substrate, and a step of supplying a processing amount of a supply amount larger than the first supply amount to the substrate. Have
2. The substrate liquid processing method according to claim 1, wherein a liquid film of the processing liquid is formed over the entire area of the substrate by supplying the substrate with the supply amount of the processing liquid larger than the first supply amount. .   The process liquid supplied to the substrate at the first supply amount forms a liquid film at the center of the substrate, and the liquid film of the process liquid is interrupted at a peripheral portion of the substrate. Substrate liquid processing method. The step of supplying the processing liquid has a step of forming a liquid film of the processing liquid over the entire area of the substrate
In the step of supplying the rinse liquid, supply of the rinse liquid to the substrate is started in a state in which a liquid film of the processing liquid is formed over the entire area of the substrate. The substrate liquid processing method as described.   The substrate liquid processing method according to claim 1, wherein a contact angle of the substrate from which the oxide film has been removed by the processing liquid is larger than a contact angle of the substrate on which the oxide film is formed. The treatment liquid contains hydrofluoric acid,
The substrate rinse processing method according to claim 1, wherein the rinse liquid is pure water. A substrate holder for holding and rotating the substrate;
A processing liquid supply unit for supplying a processing liquid to the substrate held by the substrate holding unit;
A rinsing liquid supply unit configured to supply a rinsing liquid to the substrate held by the substrate holding unit and form a liquid film of the rinsing liquid on the substrate after the processing liquid is supplied by the processing liquid supply unit; ,
A control unit for controlling the substrate holding unit, the processing liquid supply unit, and the rinse liquid supply unit,
The said control part is a substrate liquid processing apparatus which forms the liquid film of the said process liquid in the peripheral part of the said board | substrate where the liquid film of the said process liquid interrupted before forming the liquid film of the said rinse liquid.

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