TW201828356A - Liquid treatment method and liquid treatment device - Google Patents

Abstract

This invention aims to provide a liquid treatment method and a liquid treatment device capable of accurately forming a flat film on a substrate. The liquid treatment method comprises a first step S1 and a second step S2. In the first step S1, when a substrate (wafer) is being rotated, etching liquid is supplied to a film formed on the peripheral portion of the substrate, the film being thicker than that formed on the central portion. In the first step S1, etching inhibitor agent for inhibiting etching of the film caused by the etching liquid is supplied to a location nearer to the central side of the substrate than the location to which the etching liquid is supplied, so as to etch the film formed on peripheral portion of the substrate. The second step S2 is conducted after the first step S1. In the second step S2, etching liquid is supplied to the rotating substrate so for etching the film till a predetermined film thickness.

Description

Liquid processing method and liquid processing device

The present invention relates to a liquid processing method and a liquid processing apparatus for flattening a film formed on a substrate.

Generally, in the manufacturing process of a semiconductor device, a thin film such as an oxide film or a nitride film is formed on the surface of a semiconductor wafer (hereinafter, simply referred to as a "wafer") to be processed as an insulating film. As a method of forming this thin film, chemical vapor deposition (CVD) or the like is widely used. In the case where the thickness of the film at the peripheral portion of the wafer is larger than the thickness of the film at the center portion, the entire film is formed into a mortar. Such a film having an uneven film thickness causes various disadvantages. For example, when the contact holes of the film are formed, the diameters of the contact holes are uneven and the product yield is reduced.

Patent Document 1 discloses a technique of supplying a treatment liquid to a mortar-shaped film to etch the film flat.

However, in the technique disclosed in Patent Document 1, it is not easy to etch a desired amount of the outer periphery of the mortar-shaped film with a treatment liquid to flatten the entire film with good accuracy. Thus, in order to form a flat film with good accuracy over the entire substrate, further improvement is required. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-266302

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid processing method and a liquid processing apparatus capable of forming a flat film on a substrate with good accuracy. [Means for solving problems]

One aspect of the present invention relates to a liquid processing method. The liquid processing method supplies an etching solution to a substrate having a thicker film at an outer peripheral portion than a film at a central portion to etch the film, and includes a first process and a second process. In the first process, while the substrate is rotated, the etching solution is supplied to a film formed on the outer peripheral portion and thicker than the center portion, and an etching inhibitor liquid that suppresses the etching of the film by the etching solution is supplied to the film rather than being supplied. After the etching solution is located closer to the center side of the substrate, the outer peripheral film is etched. After the second process, the etching solution is supplied to the rotating substrate and etched to a predetermined film thickness.

Another aspect of the present invention relates to a liquid processing apparatus that supplies an etching solution to a substrate having a thicker film on the outer peripheral portion than a film on the center portion to etch the film. A rotating substrate holding section, a rotation mechanism for rotating the substrate holding section, a liquid supply mechanism for supplying liquid to a film formed on a substrate held by the substrate holding section, and control for controlling at least the liquid supply mechanism The controller performs the first process and the second process. The first process is to supply an etching solution and an etching inhibitor solution from a liquid supply mechanism to a film of a substrate held and rotated by a substrate holding portion, and one side rotates the substrate. An etching solution is supplied to a film formed on the outer peripheral portion and thicker than the center portion, and an etching suppressing solution that suppresses the etching of the film by the etching solution is supplied to a center side closer to the substrate than the position where the etching solution is supplied. After the second process, the outer peripheral film is etched. After the second process, the etching solution is supplied to the rotating substrate and etched to a predetermined film thickness. [Effect of the invention]

According to the present invention, a flat film can be formed on a substrate with good accuracy.

[Form for Implementing the Invention] An embodiment of the present invention will be described with reference to the drawings.

In the following, a case where the present invention is applied to a liquid processing method and a liquid processing apparatus using a wafer as a substrate and flattening an oxide film formed on the wafer with a processing liquid is exemplified.

[Configuration of Liquid Processing Apparatus] FIG. 1 is a conceptual diagram showing a schematic configuration of a liquid processing apparatus 100 according to an embodiment of the present invention. The liquid processing apparatus 100 includes a rotation mechanism 2 for holding a substrate holding portion 1 capable of horizontally and rotatably holding a wafer on which an oxide film 50 is formed on a surface, and a rotation mechanism 2 for rotating the substrate holding portion 1. In particular, the liquid supply mechanism 4 for supplying the oxide film 50 of the wafer W held by the substrate holding portion 1 and the rinse liquid (ie, the etching suppressing liquid) to the wafer W held by the substrate holding portion 1 is provided.杯 体 3。 Cup body 3.

The substrate holding portion 1 includes a rotating plate 11 connected to the rotating shaft 2a of the rotating mechanism 2 and rotating together with the rotating shaft 2a, and three support pins 12a and three holding pins 12b attached to a peripheral portion of the rotating plate 11. Each holding pin 12b can be rotated between a retracted position on the outside of the rotating plate 11 and a holding position holding the wafer W without hindering the transfer of the wafer W between the transfer arm (not shown) and the substrate holding portion 1. In the state where each holding pin 12b is arranged at the retreat position, after each supporting pin 12a receives the wafer W, each holding pin 12b is rotated to be arranged at the holding position, whereby the wafer W can be held by each supporting pin 12a and each holding The pin 12b is held. In addition, the substrate holding portion 1 can be raised and lowered by a lifting mechanism (not shown).

The liquid supply mechanism 4 includes a first liquid discharge nozzle 21 and a second liquid discharge nozzle 22 that are movable in the horizontal direction. The first liquid discharge nozzle 21 can discharge a processing liquid (for example, dilute hydrofluoric acid ((DHF))) for performing an etching treatment to dissolve the oxide film 50. The second liquid discharge nozzle 22 can selectively discharge a processing liquid (for example, diluted hydrogen) Hydrofluoric acid) and rinse fluids (such as pure water (DIW)).

A first liquid supply line 23 is connected to the first liquid discharge nozzle 21, and a second liquid supply line 28 is connected to the second liquid discharge nozzle 22. A processing liquid supply line 26 is connected to the first liquid supply line 23 via a valve 24. A processing liquid supply line 31 is connected to the second liquid supply line 28 through a valve 29, and a flushing liquid supply line 32 is connected to the second liquid supply line 28. With the switch of the switching valve 24, the presence or absence of the supply of the treatment liquid from the treatment liquid supply line 26 to the first liquid supply line 23 and the presence or absence of the discharge of the treatment liquid from the first liquid discharge nozzle 21 can be switched. Similarly, the presence or absence of the processing liquid supply from the processing liquid supply line 31 to the second liquid supply line 28 and the second liquid supply tube from the flushing liquid supply line 32 can be switched by switching the valves 29 and 30. The presence or absence of the supply of the flushing liquid in the path 28 and the presence or absence of the discharge of the processing liquid or the flushing liquid from the second liquid discharge nozzle 22. The valves 24, 29, and 30 included in the liquid supply mechanism 4 are controlled by the controller 101. Although not shown in the drawings, the processing liquid supply line 26, the processing liquid supply line 31, and the flushing liquid supply line 32 are respectively provided with a pump for sending a liquid, a flow rate control device, and the like.

The first liquid ejection nozzle 21 provided in this manner is used as a first process liquid ejection nozzle for ejecting a process liquid toward the oxide film 50 on the outer periphery of the wafer W in a first process described later (see the symbol "S1" in FIG. 3). use. On the other hand, the second liquid ejection nozzle 22 is used as a flushing liquid ejection nozzle that ejects a flushing liquid toward the oxide film 50 in the central portion of the wafer W in a first process described later, and is used in a second process (refer to the symbol of FIG. S2 ") is used as a second processing liquid discharge nozzle that discharges the processing liquid toward the oxide film 50 in the central portion of the wafer W. Therefore, the first liquid ejection nozzle 21 is relatively disposed on the outer peripheral side of the wafer W, and the second liquid ejection nozzle 22 is relatively disposed on the inside of the wafer W. The inner side mentioned here refers to the rotation axis side of the wafer W, and the liquid processing apparatus 100 shown in FIG. 1 means the side close to the rotation axis 2a. In addition, the outer peripheral side means a side remote from the rotation axis of the wafer W.

The first liquid discharge nozzle 21 is designed to have a smaller diameter than the second liquid discharge nozzle 22 and the discharge flow rate is relatively small. For example, the diameter of the second liquid discharge nozzle 22 may be set to about 1/4 inch, and the diameter of the first liquid discharge nozzle 21 may be set to 1/2 of the diameter of the second liquid discharge nozzle 22 (Ie, 1/8 inch). Since the small-diameter first liquid discharge nozzle 21 discharges a small flow of the processing liquid, a desired amount of the processing liquid can be supplied to the oxide film 50 of the wafer W with good accuracy, and the consumption of the processing liquid can be suppressed.

The first liquid ejection nozzle 21 is provided obliquely to the extending direction of the wafer W. The processing liquid discharged from the first liquid discharge nozzle 21 is discharged toward the outer peripheral side of the wafer W. This can prevent the processing liquid from bouncing back to the inside of the wafer W when the processing liquid drops on the oxide film 50 of the wafer W. The processing liquid discharged from the first liquid discharge nozzle 21 is discharged in a direction that is not perpendicular to the rotation direction of the wafer W and is the same as the rotation direction of the wafer W. Thereby, the relative speed of the processing liquid of the first liquid discharge nozzle 21 to the wafer W is small, and the rebound of the processing liquid on the oxide film 50 and the diffusion of the processing liquid on the oxide film 50 to an unexpected direction can be suppressed. The details of the discharge direction of the processing liquid from the first liquid discharge nozzle 21 will be described later (see FIGS. 4 and 5).

On the other hand, the extending direction of the second liquid ejection nozzle 22 with respect to the wafer W is arranged vertically, and the processing liquid and the rinse liquid ejected from the second liquid ejection nozzle 22 are sputtered in a vertical direction toward the oxide film 50 of the wafer W. However, the second liquid discharge nozzle 22 may be provided obliquely to the extending direction of the wafer W, and the processing liquid and the rinse liquid may be discharged from the second liquid discharge nozzle 22 in a non-vertical direction.

The first liquid discharge nozzle 21 is held by the first nozzle holder 21a, and the second liquid discharge nozzle 22 is held by the second nozzle holder 22a. A driving mechanism 48 is connected to the first nozzle holder 21a, and a driving mechanism 52 is connected to the second nozzle holder 22a. The drive mechanism 48 can move the first liquid discharge nozzle 21 and the first nozzle holder 21a, and the drive mechanism 52 can move the second liquid discharge nozzle 22 and the second nozzle holder 22a.

The above-mentioned liquid supply mechanism 4 is only an example. For example, the above-mentioned liquid discharge nozzle 22 is used as both a flushing liquid discharge nozzle and a processing liquid discharge nozzle, and the processing liquid discharge nozzle connected to the processing liquid supply line 31 through the valve 29 and the flushing connection through the valve 30 may be separately provided. The flushing liquid discharge nozzle of the liquid supply line 32 replaces the second liquid discharge nozzle 22.

The cup body 3 can receive the processing liquid and the rinsing liquid splashed from the wafer W rotating under the influence of the centrifugal force and discharge it to the outside. The bottom of the cup body 3 is provided with an exhaust passage 3a and drain pipes 3b and 3c. The exhaust passage 3a communicates with the suction side of an exhaust pump (not shown).

Each component of the liquid processing apparatus 100 is connected to a controller 101 including a computer (computer) such as a CPU and a memory, and can be controlled by the controller 101. In the liquid processing apparatus 100 shown in FIG. 1, the valve 24, the valve 29, the valve 30, the driving mechanism 48, the driving mechanism 52, and the rotation mechanism 2 are controlled by a controller 101. A user interface 102 and a memory unit 103 are also connected to the controller 101. The user interface 102 includes a keyboard for an administrator to perform an instruction input operation and the like to manage the components of the liquid processing apparatus 100, and a display that displays the operation status of the components of the liquid processing apparatus 100. The memory unit 103 is constituted by any non-transitory recording medium that can be read by a computer, and may be constituted by, for example, a CD-ROM, a hard disk, a flexible magnetic disk, or a nonvolatile memory. Here, the memory section 103 stores a recipe recording a control program, processing condition data, and the like for realizing various processes executed in the liquid processing apparatus 100 by the control of the controller 101 and other information required to control each constituent section. Therefore, the controller 101 can, for example, receive an instruction from a manager by the user interface 102 and call the corresponding recipe from the memory unit 103 for execution. The memory unit 103 of this embodiment also records programs for causing the controller 101 to execute various programs of a liquid processing method described later.

[Surface Profile of Substrate] FIG. 2 is a graph conceptually showing an example of the relationship between the horizontal position and the thickness of the wafer W to be processed. Figure 2 is based on a cross section of wafer W. The horizontal axis shows the "horizontal position" indicating the distance from the axis of rotation of wafer W in the horizontal direction, and the vertical axis shows the "horizontal distance" indicating the distance from the reference horizontal plane. Wafer thickness. " Therefore, the position on the rotation axis of the wafer W is shown by "0" on the horizontal axis of FIG. 2. In addition, in FIG. 2, the thickness of the wafer W changes linearly. FIG. 2 is a graph shown briefly for easy understanding. The actual thickness of the wafer W may vary more irregularly.

The wafer W to be processed by the liquid processing method and the liquid processing apparatus 100 of this embodiment has a thickness that is relatively larger at the outer peripheral portion than at the central portion. More specifically, the thickness of the oxide film 50 formed on the wafer W is such that the outer peripheral portion is larger than the central portion. Therefore, as shown in FIG. 2, the wafer W has approximately the same distance in a range where the distance from the center of the wafer W, that is, the rotation axis (see the horizontal axis “0” in FIG. 2), is constant in the horizontal direction. In contrast, the thickness of the wafer W increases sharply at positions near the outermost periphery of the wafer W (see near the left and right ends of the horizontal axis of FIG. 2).

In order to flatten the oxide film 50 of such a wafer W, in the liquid processing method described below, first, a portion of the outer peripheral portion of the oxide film 50 that protrudes from the inner portion is etched with a processing liquid (see the symbol "Q" in FIG. 2 ), And the difference in thickness between the outer peripheral portion and the central portion of the oxide film 50 is reduced. Thereafter, the entire oxide film 50 including the inner portion and the outer peripheral portion is etched with a processing solution, and the etching process is performed to form the entire oxide film 50 to a desired thickness. In this way, by performing the etching process in two stages, the thickness difference between the outer peripheral portion and the central portion can be effectively reduced, and the entire oxide film 50 can be planarized with good accuracy.

[Flow of liquid processing method] Next, a liquid processing method using the liquid processing apparatus 100 described above will be described.

The liquid processing method including the following first and second processes is performed by the controller 101 appropriately controlling each unit. The controller 101 obtains information about the surface profile of the oxide film 50 of the wafer W (hereinafter also referred to as "surface profile data"), and controls the switching of the valves 24, 29, and 30 based on the data. The controller 101 can obtain surface profile data in any method. For example, the controller 101 may also obtain surface profile data obtained by measuring the surface profile of the oxide film 50 before carrying the wafer W into the liquid processing apparatus 100 from an external device. In addition, the controller 101 may measure a surface profile of the oxide film 50 of the wafer W held by the substrate holding unit 1 with a measuring device (not shown), and obtain surface profile data from the measuring device.

FIG. 3 is a flowchart showing an example of a liquid processing method. In the liquid processing method described below, a substrate is supplied with a treatment liquid to a substrate having a thickness greater than that of the oxide film 50 formed at the center portion, and the oxide film 50 is etched.

In the liquid processing method shown in FIG. 3, first, a first process S1 for adjusting the thickness of the oxide film 50 on the outer periphery of the wafer W is performed, and then, a second process S1 for adjusting the thickness of the entire oxide film 50 on the wafer W is performed. Process S2. In the first process S1, while the wafer W is rotated, the processing liquid is supplied to the oxide film 50 formed on the outer peripheral portion and thicker than the center portion, and a rinse liquid that suppresses the etching of the oxide film 50 formed by the processing liquid is supplied. The oxide film 50 in the outer peripheral portion is etched to a position closer to the center side of the wafer W than the position where the processing liquid is supplied. Next, in a second process S2 performed after the first process S1, the processing liquid is supplied to the rotating wafer W, and etching is performed to a predetermined film thickness.

That is, in the first process S1, the processing liquid is supplied from the first liquid discharge nozzle 21 to the oxide film 50 formed on the rotating wafer W, and the rinse liquid is supplied from the second liquid discharge nozzle 22. At this time, the rinse liquid discharged from the second liquid discharge nozzle 22 is supplied to the position on the oxide film 50 on the center side of the wafer W, and is not the periphery of the wafer W to which the processing liquid discharged from the first liquid discharge nozzle 21 is supplied. On the side of the oxide film 50. That is, in the first process S1, the dropping position of the rinse liquid is closer to the center side of the wafer W than the dropping position of the processing liquid. Thereby, the etching liquid 50 on the outer peripheral side of the wafer W can be etched by the processing liquid. In this way, in the first process S1, only the oxide film 50 on the outer peripheral side of the wafer W is focused. Furthermore, a rinse liquid can protect the oxide film 50 on the inner side of the wafer W. That is, when the processing liquid is supplied to the outer peripheral portion of the wafer W (especially, the position near the outermost peripheral portion), if the rinse liquid is not supplied to the center of the wafer W than the supply position of the processing liquid, Then, the processing liquid dropped on the wafer W also diffuses to the center side, and there is a possibility that the center side portion of the wafer W that was not originally required to be etched is also etched. On the other hand, as in this embodiment, the processing liquid is supplied to the outer peripheral portion of the wafer W while the cleaning liquid is supplied to the center side, and the center portion of the wafer W can be covered with the cleaning liquid to protect and avoid. Treatment solution.

In addition, the first process S1 is performed after the supply of the rinse liquid to the oxide film 50 is started, and then the supply of the processing liquid to the oxide film 50 is started. That is, when the liquid processing method shown in FIG. 3 is started, the rinse liquid is supplied from the second liquid discharge nozzle 22 to the oxide film 50 (see S11 in FIG. 3), and thereafter, the supply is started from the first liquid discharge nozzle 21. Treatment liquid (S12). Specifically, before step S11, the valves 24, 29, and 30 shown in FIG. 1 are all closed. Next, by opening the valve 30 under the control of the controller 101, step S11 is started, and the rinse liquid is discharged from the second liquid discharge nozzle 22 toward the oxide film 50 in the central portion of the wafer W. The rinsing liquid supplied to the oxide film 50 spreads to the outer peripheral side as the wafer W rotates, and covers the entire surface of the oxide film 50. Next, by opening the valve 24 under the control of the controller 101, step S12 is started, and the processing liquid is discharged from the first liquid discharge nozzle 21 toward the oxide film 50 on the outer peripheral side of the wafer W.

The start of the supply of the processing liquid in step S12 is that the flushing liquid discharged from the second liquid discharge nozzle 22 covers a sufficient range on the oxide film 50 (preferably, the flushing liquid is at least covered with the treatment liquid discharged from the first liquid discharge nozzle 21 After the dripping point is closer to the inner side). Thereby, since the processing liquid is supplied in a state where the oxide film 50 inside the wafer W is protected by the rinsing liquid, the influence of the rebound of the processing liquid can be suppressed.

In particular, the processing liquid supplied to the oxide film 50 in the first process S1 is discharged from the first liquid discharge nozzle 21 so that the following condition 1 and condition 2 are satisfied.

FIG. 4 is a conceptual diagram of an example of an arrangement relationship when the first liquid discharge nozzle 21 and the wafer W are viewed from the side. The processing liquid discharged from the first liquid discharge nozzle 21 in the first process S1 splashes toward the outer periphery of the wafer W along the discharge direction indicated by the symbol “D1” and drops on the oxide film 50 on the outer periphery of the wafer W. Up (condition 1). In particular, the acute angle α formed by the processing liquid discharge direction D1 of the first liquid discharge nozzle 21 of the first process S1 to the direction D2 in which the wafer W extends should satisfy "20˚ ≦ α ≦ 70˚". When the angle α is within this range, it is possible to particularly effectively suppress the spring-back of the processing liquid to the inside of the wafer W.

FIG. 5 is a conceptual diagram showing an example of an arrangement relationship when the first liquid discharge nozzle 21 and the wafer W are viewed from above. In the first process S1, the processing liquid supplied from the first liquid ejection nozzle 21 to the oxide film 50 is spattered in the same direction as the rotation direction R of the wafer W in terms of the rotation direction R of the wafer W and drips on the oxidation. On film 50 (condition 2). In particular, in the first process S1, the direction of the projection travel path P formed by projecting the path of the processing liquid on the wafer W, and the intersection point C of the extension line PE of the projection travel path P and the outermost peripheral portion of the wafer W. The acute angle β formed by the tangential direction T of the wafer W should preferably satisfy “40˚ ≦ β ≦ 80˚”. When the angle β is in this range, the rebound of the processing liquid on the oxide film 50 and the diffusion of the processing liquid on the oxide film 50 to an unexpected direction can be particularly effectively suppressed.

In addition, the supply of the processing liquid and the rinse liquid in the first process S1 shown in FIG. 3 is continued until the thickness of the oxide film 50 on the outer peripheral portion of the wafer W reaches the same thickness as the central portion. Next, when the thickness of the oxide film 50 on the outer peripheral portion of the wafer W reaches the same thickness as the central portion, the supply of the processing liquid to the first liquid ejection nozzle 21 is stopped (S13), and then the second liquid ejection nozzle 22 is stopped. Supply of the rinse liquid (S14). Specifically, by closing the valve 24 and the valve 30 under the control of the controller 101, the discharge of the processing liquid from the first liquid discharge nozzle 21 and the discharge of the flushing liquid from the second liquid discharge nozzle 22 are stopped.

In the second process S2 performed after the first process S1, the processing liquid is supplied from the second liquid ejection nozzle 22 to the oxide film 50 of the rotating wafer W. That is, immediately after the above-mentioned step S14, the valve 29 is opened under the control of the controller 101, and the supply of the processing liquid to the oxide film 50 from the second liquid discharge nozzle 22 is started (S15). Next, the supply of the processing liquid from the second liquid discharge nozzle 22 is continued until the thickness of the oxide film 50 throughout the entire surface of the front side F1 of the wafer W reaches a predetermined thickness.

In addition, in the second process S2, since the oxide film 50 is etched throughout the entire wafer W, the processing liquid is supplied onto the oxide film 50 from the second liquid ejection nozzle 22 so as to cover the entire surface of the oxide film 50. Therefore, the second liquid discharge nozzle 22 and the second nozzle holder 22a are horizontally arranged on the rotation axis A or the vicinity of the rotation axis A of the wafer W, and the processing liquid discharged from the second liquid discharge nozzle 22 Dropped on a position on the rotation axis A in the oxide film 50 or a position near the rotation axis A. In particular, the entire oxide film 50 should be uniformly etched, and the diffusion of the processing liquid should be considered, and the processing liquid of the second liquid ejection nozzle 22 should be placed on the oxide film 50 slightly away from the rotation axis A. In addition, when the processing liquid droplet of the second liquid discharge nozzle 22 is dropped on the center of the wafer W passing through the rotation axis A, the fresh processing liquid is always supplied to the place where the centrifugal force does not work. Since the etching progresses faster than the etching of other parts, it is not suitable from the viewpoint of uniformly etching the entire oxide film 50. In this way, in the second process S2, the processing liquid is not supplied to the wafer W at the position where the processing liquid has been supplied in the first process S1, but the processing liquid is supplied to a position more than the position where the processing liquid has been supplied in the first process S1. Near the center side of the wafer W.

Further, in order to cover the sufficient range of the oxide film 50 with the processing liquid, it is desirable to make the discharge amount of the processing liquid of the second liquid discharge nozzle 22 sufficiently large and the rotation speed of the wafer W sufficiently large. Therefore, the supply amount of the processing liquid of the second liquid discharge nozzle 22 of the second process S2 to the oxide film 50 per unit time is greater than the supply of the processing liquid of the first liquid discharge nozzle 21 of the second process S1 to the oxide film 50 per unit time. Of supply. The rotation speed of the wafer W in the second process S2 is faster than the rotation speed of the wafer W in the first process S1.

For example, the wafers W rotating at a lower first speed (for example, 200 rpm (revolution per minute)) between the above steps S11 to S12 are supplied from the second liquid ejection nozzle 22 A relatively large amount of the first supply amount of washing liquid (for example, 1500 ml / min (ml / min)) can cover the entire surface of the oxide film 50 with the washing liquid. In addition, a relatively small amount of the second supply amount (for example, 500 ml) can be supplied from the second liquid ejection nozzle 22 to the wafer W rotating at the second rotation speed (for example, 200 rpm) at a relatively low speed between steps S12 to S13. / min), and a relatively small amount of the third supply amount (for example, 400 ml / min) of the treatment liquid can be supplied from the first liquid discharge nozzle 21. In addition, a fourth supply amount (a larger amount) is supplied from the second liquid ejection nozzle 22 through the wafer W rotated at a third rotation speed (for example, 750 rpm) faster than the second rotation speed between the steps S13 to S14. For example, a washing liquid of 1500 ml / min) may cover the entire surface of the oxide film 50.

In addition, the specific rotation speed of the wafer W between steps S12 to S13 should be set according to the contour of the oxide film 50 on the outer periphery of the wafer W. That is, in steps S12 to S13, the rinsing liquid supplied to the wafer W receives centrifugal force and diffuses toward the outer periphery of the wafer W, and the magnitude of the centrifugal force acting on the rinsing liquid changes according to the rotation speed of the wafer W. On the other hand, the state of the boundary between the rinse liquid and the processing liquid on the wafer W changes according to the centrifugal force received by the rinse liquid. When the larger centrifugal force is received by the rinse liquid, the processing liquid supplied to the outer periphery of the wafer W The more the etching effect is suppressed by the washing liquid. Therefore, the faster the rotation speed of the wafer W, the greater the influence of the rinsing liquid on the outer periphery of the wafer W, and the slower the change in the amount of etching near the boundary between the processing liquid and the rinsing liquid, the slower the wafer W direction The etched contours form a gentle angle. On the other hand, the slower the rotation speed of the wafer W, the smaller the influence of the rinsing liquid on the outer periphery of the wafer W, and the sharper the change in the amount of etching near the interface between the processing liquid and the rinsing liquid, the faster the direction of the wafer W The etched contour on the top forms a steep angle. Therefore, the manufacturing process between steps S12 to S13 considers such an etching characteristic, and it is preferable to make the wafer W at a rotation speed suitable for etching the oxide film 50 on the outer periphery of the wafer W to the same thickness as the oxide film 50 in the center. Spin.

Further, by performing the above steps S14 and S15 almost simultaneously, the liquid discharged from the second liquid discharge nozzle 22 can be switched from the rinse liquid to the processing liquid without interruption. In addition, while the rotation speed of the wafer W is gradually reduced from the third speed to the fourth speed (for example, 500 rpm) between steps S15 to S16, a larger amount of the fifth is supplied from the second liquid ejection nozzle 22 An amount (for example, 1500 ml / min) of the processing liquid is supplied to the wafer W, so that the processing liquid can cover the entire surface of the oxide film 50.

Next, when the thickness of the oxide film 50 throughout the entire wafer W reaches a desired thickness, the valve 29 is closed under the control of the controller 101, and the supply of the processing liquid from the second liquid discharge nozzle 22 is stopped (S16). After that, the valve 30 is opened under the control of the controller 101, and the rinse liquid is supplied from the second liquid discharge nozzle 22 to the oxide film 50 (S 17). Then, after the processing liquid remaining on the oxide film 50 is washed away with the washing liquid, the valve 30 is closed under the control of the controller 101, and the supply of the washing liquid to the oxide film 50 from the second liquid discharge nozzle 22 is stopped (S18). In addition, a sixth supply amount (for example, 1500 ml) in which a larger amount is supplied from the second liquid ejection nozzle 22 through the wafer W rotating at a fifth speed (for example, 1500 rpm) faster than the fourth speed between the above steps S17 to S18. / min), which can cover the entire surface of the oxide film 50.

In addition, after the above-mentioned step S18, the wafer W can be rotated at a relatively high speed (for example, 1500 ml / min) in a state where the discharge of liquid from the first liquid discharge nozzle 21 and the second liquid discharge nozzle 22 is stopped. Spin to dry. The oxide film 50 of the wafer W is planarized by going through the series of processing steps described above.

As described above, according to the liquid processing apparatus 100 and the liquid processing method of this embodiment, by performing the first process S1 and the second process S2 in this order, a flat oxide film 50 can be formed on the wafer W with good accuracy.

In particular, if the processing liquid is discharged from the first liquid discharge nozzle 21 so as to satisfy the above-mentioned condition 1 (refer to FIG. 4) and condition 2 (refer to FIG. 5), the oxide film 50 can be effectively prevented from being etched in unexpected places, and it can be suppressed Bounce and spread of treatment fluid.

The inventors of the present case measured the correlation between the etching amount of the oxide film 50 and the horizontal position while changing the discharge angle of the processing liquid of the first liquid discharge nozzle 21, and evaluated the etching amount of the oxide film 50 and the horizontal position. relationship. Specifically, inspection 1 and inspection 2 were performed, and the inspection 1 was performed by measuring the discharge angle of the treatment liquid a plurality of times within a range satisfying the above-mentioned conditions 1 and 2, and the inspection 2 was performed when the above condition 1 was not satisfied. And / or the range of the condition 2 was changed several times by measuring the discharge angle of a process liquid. As a result, in the inspection 1 that satisfies the above-mentioned condition 1 and condition 2, in either case, "the innermost position on the oxide film 50 of the oxide film 50 was observed to be removed by the treatment liquid" and "the treatment liquid dropped on the oxide film The difference between the "50 positions" (hereinafter referred to as the "treatment liquid deviation amount") falls within a range of approximately 10 mm (mm). On the other hand, in the conditions other than the conditions 1 and 2 described above, which are substantially the same as those in the inspection 1 and do not satisfy the conditions 1 and 2, the majority of the cases are that the deviation of the processing liquid exceeds 10 mm, and there are many cases. The deviation of the processing liquid is more than 20mm. It can also be known from the results of these inspections 1 and 2 that if the processing liquid is discharged from the first liquid discharge nozzle 21 to satisfy the above conditions 1 and 2, the springback and diffusion of the processing liquid can be suppressed, and etching can be performed with good accuracy. A target in the oxide film 50.

In addition, the surface of the wafer W that has been etched with the processing liquid can be made hydrophobic. To properly form a processing liquid film on a hydrophobized surface, a large amount of processing liquid needs to be supplied, or the wafer W is rotated at high speed. On the other hand, in the above-mentioned first process S1, from the viewpoint of preventing the processing liquid from being spattered to the inside of the wafer W, it is not easy to supply a large amount of processing liquid or set the rotation speed of the wafer W to a high speed. Therefore, the method of first performing the second process S2 and then performing the first process S1 is not suitable because the etching process of the first process S1 is unstable. On the other hand, it is suitable to perform the method shown in FIG. 3 of the first process S1 before the second process S2 because the first process S1 and the second process S2 can be stably performed.

[Modifications] The present invention is not limited to the above-mentioned embodiments and modification examples, and may include various modifications that can be conceived by those skilled in the art, and the effects exerted by the present invention are not limited to the above matters. Therefore, various additions, changes, and partial deletions of the requirements described in the scope of the patent application and the specification can be made without departing from the technical idea and spirit of the present invention.

For example, in the above embodiment, only the oxide film 50 on the surface side F1 of the wafer W is the object of etching by the processing liquid, and the processing liquid and / or the processing on the back side F2 of the wafer W may also be washed. The supply of the liquid is performed together with the supply of the processing liquid and / or the rinse liquid to the surface side F1 of the wafer W. At this time, it is preferable to start supplying the liquid to the back side F2 of the wafer W in a state where the liquid has been supplied to the front side F1 of the wafer W. Thereby, the liquid supplied to the back surface side F2 of the wafer W can be effectively prevented from revolving into the front surface side F1.

For example, in the first process S1, the rinsing liquid and the processing liquid are supplied to the oxide film 50 on the surface side F1 of the wafer W, and in the second process S2, the processing liquid is supplied to the oxidation of the surface side F1 of the wafer W. Film 50. The processing liquid and / or the rinsing liquid may also be supplied to at least one of the first process S1 and the second process S2 to the back side F2 of the wafer W. At this time, in a state where the processing liquid of at least one of the first process S1 and the second process S2 is supplied to the front side F1 of the wafer W, the supply of the processing liquid and / or the flushing to the back side F2 of the wafer W is started. liquid. For example, a larger amount (for example, 1000 ml / min) of the rinse liquid can be supplied to the back side F2 of the wafer W in the first process S1, and a larger amount (for example, 1000 ml / min) of the processing liquid can be supplied in the second process S2. To the oxide film formed on the back side F2 of the wafer W. In addition, the supply of the processing liquid and / or the rinsing liquid to the back side F2 of the wafer W can be achieved by using nozzles and valve devices having the same structure as the nozzles 21 and 22 and the valves 24, 29, and 30 provided on the front side F1. On the back surface side F2, the processing liquid and / or the rinsing liquid are discharged from the nozzle toward the back surface side F2 of the wafer W.

Moreover, the specific composition of the processing liquid and the rinsing liquid is not particularly limited, and a liquid that can remove a film such as the oxide film 50 formed on a substrate such as a wafer W can be used as the processing liquid, and such processing can be appropriately washed out The liquid is used as a rinsing liquid. The processing liquid discharged from the first liquid discharge nozzle 21 and the processing liquid discharged from the second liquid discharge nozzle 22 may be liquids having the same composition or liquids having different compositions. The processing liquid supplied to the back side of the wafer W may have the same composition as the processing liquid discharged from the first liquid discharge nozzle 21 and / or the second liquid discharge nozzle 22, or may have a different composition. The rinse liquid supplied to the back side of the wafer W may have the same composition as the rinse liquid discharged from the second liquid discharge nozzle 22, or may have a different composition.

1‧‧‧ substrate holding section

2‧‧‧ rotating mechanism

2a‧‧‧rotation axis

3‧‧‧ cup body

3a‧‧‧Exhaust passage

3b‧‧‧Drain tube

3c‧‧‧Drain tube

4‧‧‧liquid supply mechanism

11‧‧‧ rotating plate

12a‧‧‧Support pin

12b‧‧‧ keep pin

21‧‧‧The first liquid discharge nozzle

21a‧‧‧1st nozzle holder

22‧‧‧ 2nd liquid discharge nozzle

22a‧‧‧Second nozzle holder

23‧‧‧The first liquid supply line

24‧‧‧ Valve

26‧‧‧ Treatment liquid supply line

28‧‧‧ 2nd liquid supply line

29‧‧‧ Valve

30‧‧‧ Valve

31‧‧‧treatment liquid supply line

32‧‧‧Flushing liquid supply line

48‧‧‧Drive mechanism

50‧‧‧ oxide film

52‧‧‧Drive mechanism

100‧‧‧ liquid processing equipment

101‧‧‧controller

102‧‧‧user interface

103‧‧‧Memory Department

A‧‧‧ rotation axis

C‧‧‧ intersection

D1‧‧‧ Spit Out Direction

D2‧‧‧wafer W extension

F1‧‧‧ surface side

F2‧‧‧Back side

P‧‧‧ projection travel path

Extension line of PE‧‧‧projection travel path P

Q‧‧‧The part of the outer periphery of the oxide film 50 that protrudes from the inner part

W‧‧‧ Wafer

Rotation direction of R‧‧‧wafer W

S1‧‧‧The first process

S2‧‧‧ 2nd process

S11 ~ S18‧‧‧step

T‧‧‧ Direction of tangent of wafer W

α‧‧‧ angle

β‧‧‧ angle

FIG. 1 is a conceptual diagram showing a schematic configuration of a liquid processing apparatus according to an embodiment of the present invention. [Fig. 2] A conceptual diagram showing an example of the relationship between the horizontal position and the thickness of a wafer to be processed. Fig. 3 is a flowchart showing an example of a liquid processing method. FIG. 4 is a conceptual diagram showing an example of an arrangement relationship when the first liquid discharge nozzle and the wafer are viewed from the side. 5 is a conceptual diagram showing an example of an arrangement relationship when the first liquid ejection nozzle and the wafer are viewed from above.

Claims (10)

A liquid processing method that supplies an etching solution to a substrate having a thicker film at an outer peripheral portion than a film at a central portion to etch the film, and includes the following processes: A first process in which a substrate is rotated while an etching solution is supplied to a substrate A film that is thicker at the outer periphery than at the center, and supplies an "etching suppressant that suppresses the etching of the film by the etchant" to "a position closer to the center side of the substrate than where the etchant is supplied" The second step, after the first step, the etching solution is supplied to the rotating substrate and etched to a predetermined film thickness. For example, in the liquid processing method of claim 1 in the scope of patent application, in the second process, the etching solution is not supplied to the substrate where the etching solution has been supplied in the first process, and the etching solution is not supplied. The supply is performed closer to the center side of the substrate than the position where the etching solution has been supplied in the first process. For example, in the liquid processing method of the first or second scope of the patent application, in the first process, the discharge direction of the etching solution from the first processing solution discharge nozzle forms an acute angle α with respect to the direction in which the substrate extends. , Which satisfies 20˚ ≦ α ≦ 70˚. For example, in the liquid processing method of the first or second scope of the patent application, in the first process, the direction of the projection travel path formed by projecting the path of the etching solution on the substrate and traveling on the projection The acute angle angle β formed by the two directions of the tangent line of the substrate at the intersection of the extension of the path and the outermost peripheral portion of the substrate satisfies 40˚ ≦ β ≦ 80˚. For example, the liquid processing method according to item 1 or item 2 of the patent application scope, wherein the first process starts to supply the etching solution after the supply of the etching suppression solution is started. For example, in the liquid processing method of the first or second scope of the patent application, in the first process, the etching inhibitor liquid and the etching solution are supplied to the surface side of the substrate, and in the second process, the etching is performed. The liquid is supplied to the front side of the substrate, and the second liquid is supplied to the back side of the substrate in at least one of the first process and the second process, and at least in the first process and the second process. In any state where the etching solution is supplied to the front surface side of the substrate, the second liquid is supplied to the back surface side of the substrate. For example, the liquid treatment method of the first or second item of the patent application scope, wherein the supply amount of the etching solution per unit time in the second process is larger than the supply amount of the etching solution per unit time in the first process Supply amount. For example, the liquid processing method of the first or second scope of the patent application, wherein the rotation speed of the substrate in the second process is faster than the rotation speed of the substrate in the first process. For example, the liquid treatment method of the first or second scope of the patent application, wherein the etching suppression liquid is pure water. A liquid processing device that supplies an etching solution to a substrate having a thicker outer peripheral film than a central film and etches the film, and includes: a substrate holding portion for holding a substrate in a rotatable manner; a rotating mechanism for To rotate the substrate holding portion; a liquid supply mechanism to supply liquid to a film formed on the substrate held by the substrate holding portion; and a controller to control at least the liquid supply mechanism; the controller The following processes are performed: The first process is to supply an etching solution and an etching inhibitor solution from the liquid supply mechanism to the film of the substrate held and rotated by the substrate holding portion, and while the substrate is rotated, the etching solution is supplied To a film that is thicker than the center formed on the outer peripheral portion, and supply the "etching suppression liquid that suppresses the etching of the film by the etchant" to "the center closer to the substrate than the position where the etchant is supplied" Side ", and the outer peripheral film is etched; in the second step, after the first step, an etching solution is supplied to the rotating substrate to etch to a predetermined film thickness.