JP5541311B2 - Substrate cleaning method, substrate cleaning apparatus, developing method, developing apparatus, and storage medium - Google Patents

Description

The present invention is a substrate cleaning method for cleaning and drying the substrate, the substrate cleaning apparatus, a developing method, a developing device, and a storage medium storing a program for implementing the method for cleaning a substrate or the development process.

  Conventionally, in a photoresist process, which is one of semiconductor manufacturing processes, a resist is applied to the surface of a semiconductor wafer (hereinafter referred to as a wafer), which is a substrate, and developed after exposure to create a resist pattern. Such a process is generally performed using a system in which an exposure apparatus is connected to a coating / developing apparatus for coating and developing a resist.

  In such a series of processes, in the development process, a developer is deposited on the wafer, and after that, for example, the wafer is kept stationary for a predetermined time, and the soluble portion of the resist is dissolved to form a pattern. A cleaning process is performed to remove the dissolved resist together with the developer from the wafer surface. Conventionally, a cleaning solution is supplied to the center of the wafer, and the liquid film is expanded by the centrifugal force. The melt and the developer are removed from the wafer by placing them in a flow.

  However, this spin cleaning cannot remove the dissolved product sufficiently and has not been regarded as a problem when the line width of the pattern is wide. However, when the line width becomes narrower, the remaining dissolved product becomes a development defect. The degree that appears as becomes stronger. For this reason, the present situation is that the spin cleaning is performed for as long as 60 seconds, for example. Even if washing is performed for such a long time, the dissolved product is still left behind, and it may be difficult to say that sufficient washing is performed.

  Therefore, the applicant of the present application discharges the cleaning liquid from the cleaning liquid nozzle to the center of the wafer while rotating the wafer, and then moves the cleaning liquid nozzle slightly to the outer side of the wafer to discharge N2 gas from the gas nozzle to the center of the wafer. A method is proposed in which the core of the dry region is formed, and then the cleaning liquid nozzle is moved to the outer side of the wafer while discharging the cleaning liquid so as not to catch up with the dry region (Patent Document 1). According to this method, there is an advantage that a high cleaning effect can be obtained and cleaning can be performed in a short time.

  On the other hand, device patterns are becoming increasingly finer and thinner, and with this trend, there is an increasing demand for higher exposure resolution. In order to improve the resolution by further improving the exposure technique using an existing light source such as argon fluoride (ArF) or krypton fluoride (KrF), exposure is performed in a state where a liquid phase that transmits light is formed on the surface of the substrate ( Hereinafter, “immersion exposure” is being studied. Immersion exposure is a technique that allows light to pass through, for example, ultrapure water, and uses the feature that the wavelength of ArF at 193 nm is substantially 134 nm in water because the wavelength is shorter in water.

  One of the problems of such immersion exposure is the possibility that water droplets remain on the wafer and are transferred from the exposure apparatus to the coating and developing apparatus. The exposed wafer W is heat-treated, but if there are water droplets on the wafer, or if the water droplets are dried and a so-called water mark is formed, which is a soaking of water, the pattern resolution directly underneath is adversely affected. There is. For this reason, it is necessary to clean the surface of the wafer after exposure to remove water droplets.

  Also, in the immersion exposure process, the surface of the exposed wafer has a high water repellency, for example, water, in order to improve the scan followability of the exposure unit immersion part (lens tip) and ensure the same throughput as the conventional exposure apparatus. It has been studied to form a protective film having a static contact angle of about 75 to 85 degrees. However, since the water repellency of the protective film is high, there is a high possibility that small water droplets remain on the surface of the protective film. come. Note that the static contact angle of water refers to an arc that forms the outer edge of a water droplet when the water droplet is viewed in cross section when the water droplet is attached to the surface of the substrate, as shown in FIG. The angle θ between the tangent line and the surface. In addition, the static contact angle of water may be lowered by development processing. Hereinafter, the description simply referred to as a contact angle is a static contact angle, and further indicates a static contact angle of water before development processing.

  Then, if particles remain on the surface of the substrate to scan the exposure unit immersion part, the particles are taken into the liquid below the exposure unit immersion part, and development based on the particles at each scanning position Since defects occur, it is necessary to cleanly remove the particles by cleaning the wafer surface before entering the immersion exposure. However, in the method of Patent Document 1, if the contact angle of the wafer surface is high, that is, the surface has high water repellency, particles (before immersion exposure) or water droplets (after immersion exposure) are formed in a region away from the vicinity of the center of the wafer. ) Is difficult to remove sufficiently.

  The reason for this is that the cleaning liquid R is discharged from the cleaning liquid nozzle 11 to the center of the wafer W as shown in FIG. 26A and spread over the entire surface of the wafer W, and then from the gas nozzle 12 as shown in FIG. When the core of the dry region is formed at the center of the wafer W by discharging N2 gas, the thin liquid film moves outward at a fairly high speed because the surface of the wafer W has high water repellency. This thin liquid film is torn off and remains as water droplets M. In the region close to the center of the wafer W, the cleaning liquid R is first discharged to the center of the wafer W and the centrifugal force in this region is small, so that the cleaning effect is high and water droplets do not substantially remain.

  In addition, it has been studied to use a resist film (having a static contact angle of water of 85 degrees or more) with higher water repellency (higher hydrophobicity) without using the protective film. When such a resist is used, the water repellency of the wafer surface is high even after development, and the method of Patent Document 1 has the following problems.

  When the water repellency of the wafer surface is not so high, that is, when the contact angle of water is not so large, after the cleaning liquid is discharged to the center of the wafer and spread over the entire surface, a dry core is formed and spread. As shown in FIG. 27 (a), the cleaning liquid R remaining in the recess 13 of the resist pattern is drawn along with the pattern surface outside the recess 13 toward the wafer outward, and the cleaning liquid is discharged from the recess 13. . On the other hand, when the contact angle of water on the surface of the wafer reaches 85 degrees, the spreading speed of the dry core is considerably increased, that is, the speed of the thin liquid film on the pattern surface toward the outside of the wafer is considerably increased. As shown in FIG. 27 (b), the cleaning liquid R in the recess 13 is torn off from the liquid film and left in the recess 13. Since the cleaning solution R contains a dissolved product of the resist, it causes development defects. This development defect hardly occurs in the region close to the center of the wafer for the reasons described above, but is remarkably generated outside the region.

In Patent Document 2, the processing liquid nozzle is rapidly moved to a position 10 mm to 15 mm away from the center of the wafer, and then N2 gas is blown from the N2 nozzle to the center of the wafer quickly to dry the center of the wafer. Is described, and a cleaning method is described in which a processing liquid nozzle is scanned around the periphery of a wafer at a speed of 3 mm / second or less. However, Patent Document 2 does not describe a technique that can reliably clean the surface from the vicinity of the center of the wafer to the periphery when the surface of the wafer has a large contact angle of 85 degrees or more. Specifically, depending on the size of the cleaning liquid nozzle and the gas nozzle, there arises a problem that a dry region cannot be formed well, or the nozzle moving speed is slow and the process time is long.
Japanese Patent Laying-Open No. 2006-80315 (FIG. 7, paragraphs 0040 and 0043) WO2005-50724 (FIG. 7, paragraphs 0040 and 0043)

The present invention has been made under such circumstances, it is to provide a technique which can obtain a cleaning effect has a high, yet can be cleaned in a short time.

The substrate cleaning method of the present invention is a substrate cleaning method for cleaning and drying a substrate whose surface is water repellent ,
Rotating around an axis perpendicular to the substrate while holding the substrate substantially horizontal;
Supplying the cleaning liquid to the central portion on the rotating substrate using a cleaning liquid nozzle for discharging the cleaning liquid;
Moving the cleaning liquid nozzle so that a position on the substrate that receives the cleaning liquid discharged from the cleaning liquid nozzle moves from the central part on the rotating substrate toward a peripheral part on the substrate by a certain distance;
By discharging a gas to the central portion on the rotating substrate for a predetermined time using a gas nozzle that discharges the gas while maintaining a state where the position on the substrate that receives the cleaning liquid is separated from the central portion on the substrate by a certain distance. Forming a dry region in the center of the substrate;
After the drying region is formed in the center on the substrate, the cleaning liquid nozzle is moved so that the position on the substrate that receives the cleaning liquid continuously moves toward the peripheral edge on the rotating substrate, and The gas nozzle is continuously moved so that the position on the substrate that receives the gas discharged from the gas nozzle follows the moving path of the position on the substrate that receives the cleaning liquid while being spaced apart from the position on the substrate that receives the cleaning liquid by the predetermined distance. A process of
With
The step of moving the cleaning liquid nozzle and continuously moving the gas nozzle includes:
The drying region formed on the substrate is performed so that the moving speed of the cleaning liquid nozzle and the gas nozzle is smaller than the speed of spreading the substrate.

  For example, in the step of rotating the substrate, the substrate rotates at a first rotational speed in a state where the position on the substrate that receives the cleaning liquid is located at the center of the substrate, and the position on the substrate that receives the cleaning liquid is on the substrate. A step of changing the rotation speed of the substrate stepwise or continuously so that the substrate rotates at a second rotation speed lower than the first rotation speed while being positioned at the periphery.

The fixed distance is, for example, 9 mm or more and 15 mm or less.

The substrate cleaning method of the present invention is performed, for example, following the step of moving the gas nozzle together with the cleaning nozzle, and the cleaning liquid is received at a position where the position on the substrate that receives the cleaning liquid is 2 mm to 10 mm away from the peripheral edge of the substrate while rotating the substrate. A step of stopping the discharge of
A step of continuously rotating the substrate in order to remove the cleaning solution on the substrate from the substrate by centrifugal force after stopping the discharge of the cleaning solution;
It has.

The step of moving the cleaning nozzle so that the position on the substrate that receives the cleaning liquid discharged from the cleaning nozzle moves a certain distance from the central portion on the substrate toward the periphery on the substrate,
For example, it is performed while rotating the substrate at 1500 rpm to 2000 rpm.

The predetermined time for supplying the gas to the central portion on the substrate to form the dry region is, for example, 0.5 seconds.

The substrate cleaning apparatus of the present invention is a substrate cleaning apparatus for cleaning and drying a substrate whose surface is water-repellent ,
Substrate holding means for holding the substrate substantially horizontally;
A rotation driving means for rotating the substrate held by the substrate holding means around an axis perpendicular to the substrate;
A cleaning liquid nozzle for discharging the cleaning liquid onto the rotating substrate;
A cleaning liquid nozzle drive mechanism for moving the cleaning liquid nozzle;
A gas nozzle that discharges gas onto a rotating substrate;
A gas nozzle drive mechanism for moving the gas nozzle;
Control means for controlling the substrate holding means, the rotation driving means, the cleaning liquid nozzle driving mechanism, and the gas nozzle driving mechanism,
The control unit rotates the substrate around the axis perpendicular to the substrate while holding the substrate substantially horizontally by the rotation driving unit, and discharges the cleaning solution from the cleaning solution nozzle to the central portion on the rotating substrate. The center on the substrate is discharged by discharging the gas from the gas nozzle to the central portion on the rotating substrate for a predetermined time while maintaining the position on the substrate that receives the discharged cleaning liquid at a certain distance from the central portion on the substrate. After the dry region is formed in the central portion and the dry region is formed in the central portion on the substrate, the cleaning liquid is moved so that the position on the substrate that receives the cleaning liquid continuously moves toward the peripheral portion on the rotating substrate. The cleaning liquid nozzle is moved by a nozzle drive mechanism, and the position on the substrate that receives the gas discharged from the gas nozzle is fixed from the position on the substrate that receives the cleaning liquid. By the gas nozzle drive mechanism to follow a movement path of the position on the substrate for receiving the washing liquid away spaced while moving the gas nozzle continuously,
The moving speed of the cleaning liquid nozzle and the gas nozzle that are moved together in a state where the position on the substrate that receives the gas and the position on the substrate that receives the cleaning liquid are separated from each other by a certain distance is lower than the speed at which the drying region spreads the substrate. It is controlled by the control means so as to be a speed.

For example, the control means is configured such that the substrate rotates at a first rotational speed in a state where the position on the substrate that receives the cleaning liquid is located at a central portion on the substrate, and the position on the substrate that receives the cleaning liquid is a peripheral portion on the substrate. The rotation speed of the substrate is changed stepwise or continuously by the rotation driving means so that the substrate rotates at a second rotation speed lower than the first rotation speed in the state of being positioned at the position.

  For example, the fixed distance is 9 mm or more and 15 mm or less.

For example, the control means discharges the cleaning liquid when the position on the substrate that receives the cleaning liquid that moves toward the peripheral edge of the substrate on the rotating substrate is located 2 mm to 10 mm away from the peripheral edge of the substrate. And after the discharge of the cleaning liquid is stopped, the substrate is continuously rotated in order to remove the cleaning liquid on the substrate from the substrate by centrifugal force. For example, the control means discharges the cleaning liquid from the cleaning nozzle to the central portion on the rotating substrate, and then the position on the substrate that receives the cleaning liquid discharged from the cleaning nozzle is separated from the central portion on the substrate by a certain distance. The substrate is rotated at 1500 rpm to 2000 rpm while the cleaning nozzle is moved so that The predetermined time for supplying the gas to the central portion on the substrate to form the dry region is, for example, 0.5 seconds.

The development method of the present invention is a development method in which a resist film is formed and a developer is supplied to the exposed substrate to form a pattern on the resist film,
  A developer supply step of supplying the developer to the substrate;
  Next, a cleaning liquid supply step for supplying a cleaning liquid to the substrate;
  With
  The cleaning liquid supply step is performed using the substrate cleaning method described above. The developing device of the present invention is a developing device in which a resist film is formed and a developer is supplied to the exposed substrate to form a pattern on the resist film.
  A developer supply unit for supplying the developer to the substrate;
  A cleaning liquid supply unit for supplying a cleaning liquid to the substrate supplied with the developer for cleaning;
With
  The cleaning liquid supply unit includes the substrate cleaning apparatus described above.

  By the way, when cleaning is performed after the development process for supplying the developer to the substrate, the static contact angle of water on the substrate is 85 degrees or more means that the static contact angle of water on the substrate before the development process is 85 degrees or more. It shows that. For the substrate surface where the static contact angle of water was 85 degrees or more before the development processing due to the change of the resist surface state depending on the developer, the static contact angle is slightly more than 85 degrees during cleaning. However, since it is difficult to accurately measure the static contact angle after the development process and before the cleaning process, the cleaning process in this case must be performed immediately after the development process. Define the static contact angle as follows:

Storage medium of the present invention is used in apparatus for cleaning the surface of the base plate, a storage medium storing a program running on a computer,
The program includes a group of steps so as to execute the substrate cleaning method or the developing method .

According to the present invention, after the gas nozzle is discharged from the gas nozzle to the central portion on the rotating substrate to form the drying region, the position on the substrate that receives the cleaning liquid continuously moves toward the peripheral edge on the substrate. The cleaning nozzle is moved, and the position on the substrate that receives the gas discharged from the gas nozzle follows the movement path of the position on the substrate that receives the cleaning liquid while being spaced apart from the position on the substrate that receives the cleaning liquid. The gas nozzle is continuously moved. As a result, a high cleaning effect can be obtained, and cleaning can be performed in a short time. In particular, if the present invention is applied to the substrate after the development is performed by supplying the developer to the exposed surface of the substrate, it is almost impossible to develop defects as will be apparent from the evaluation test described later. This can be reduced and greatly contributes to the improvement of yield.
In addition, development defects can be more reliably reduced by preventing the droplets attached to the nozzles from dropping from the processing atmosphere to the formed dry region.

[First embodiment]
An embodiment in which the substrate cleaning apparatus of the present invention is combined with a developing apparatus will be described. In FIG. 1, reference numeral 2 denotes a spin chuck which is a substrate holding unit for sucking and adsorbing a substrate, for example, a central portion on the back side of the wafer W and holding it in a horizontal posture. The spin chuck 2 is connected to a drive mechanism 22 including a rotation mechanism via a rotation shaft 21 and is configured to be able to rotate and move up and down while holding the wafer W. In this example, the center of the wafer W is set on the rotation shaft 21 of the spin chuck 2.

  Three cups having an upper opening are provided so as to surround the wafer W on the spin chuck 2. The cup body 3 includes a rectangular outer cup 31 on the upper side and a cylindrical outer cup 31 on the lower side and a cylindrical inner cup 32 whose upper side is inclined inward, and is connected to the lower end of the outer cup 31. The outer cup 31 is moved up and down by 33, and the inner cup 32 is further pushed up and down by a step formed on the inner peripheral surface of the lower end side of the outer cup 31.

  A circular plate 34 is provided on the lower side of the spin chuck 2, and a liquid receiving portion 35 whose cross section is formed in a concave shape is provided over the entire circumference of the circular plate 34. A drain discharge port 36 is formed on the bottom surface of the liquid receiving part 35, and the developer and the cleaning liquid spilled from the wafer W or shaken off and stored in the liquid receiving part 35 are passed through the drain discharge port 36. It is discharged outside the device. A ring member 37 having a mountain-shaped cross section is provided outside the circular plate 34. Although not shown, elevating pins that are, for example, three substrate support pins penetrating the circular plate 34 are provided, and the wafer W is spin chucked by the cooperative action of the elevating pins and a substrate transfer means (not shown). It is comprised so that it may pass to 2.

  Further, the developing device of this example (also used as a substrate cleaning device) includes a developing solution nozzle 23, a cleaning solution nozzle 4, and a gas nozzle 5. The developer nozzle 23 includes a strip-shaped discharge port, for example, a slit-shaped discharge port 23 a (see FIG. 2) that extends in the diameter direction of the wafer W held by the spin chuck 2. The nozzle 23 is connected to a developer supply system 25 via a developer supply path 24, for example, a pipe. The developer supply system 25 includes a developer supply source, a supply control device, and the like.

  The developer nozzle 23 is supported on one end side of a nozzle arm 26, which is a support member, and the other end side of the nozzle arm 26 is connected to a moving base 27 having a lifting mechanism (not shown). For example, 27 is configured to be movable in the lateral direction along a guide member 28 extending in the X direction on the bottom surface of the exterior body of the unit by a driving source (not shown) that forms a moving mechanism together with the lifting mechanism. In the figure, reference numeral 29 denotes a standby portion of the developer nozzle 23, and the nozzle standby portion 29 performs cleaning of the nozzle tip.

  The cleaning liquid nozzle 4 has a discharge port 40 (see FIG. 4), and is connected to a cleaning liquid supply system 43 via a cleaning liquid supply path 42 such as a pipe. The cleaning liquid supply system 43 includes a cleaning liquid supply source, a supply control device, and the like. The supply control device includes a pump, a valve, and the like capable of discharging flow rate. Further, as shown in FIG. 3, the cleaning liquid nozzle 4 is fixed to a nozzle arm 44 via a nozzle holding portion 41, and this nozzle arm 44 is connected to a moving base body 45 provided with an elevating mechanism. The moving base 45 is configured to be movable in the lateral direction along the guide member 28 without interfering with the developer nozzle 23 by a driving source (not shown) that forms a moving mechanism together with a lifting mechanism. In the figure, reference numeral 46 denotes a standby portion of the cleaning liquid nozzle 4.

  The gas nozzle 5 is connected to a gas supply system via piping. In this example, the gas supply system includes an N2 (nitrogen) gas supply source that is an inert gas, a supply control device, and the like. Further, the gas nozzle 5 is fixed to, for example, a nozzle holding unit 41 and is configured to move together with the cleaning liquid nozzle 4 by a nozzle arm 44.

  Next, the separation position between the cleaning liquid nozzle 4 and the gas nozzle 5 will be described with reference to FIG. 4 showing a state in which the cleaning liquid R and N2 gas are discharged. 4A and 5A indicate the cleaning liquid discharge (supply) position and the gas discharge (supply) position discharged from the discharge port 40 of the cleaning liquid nozzle 4 and the discharge port 50 of the gas nozzle 5 onto the wafer W, respectively. The cleaning liquid discharge position 4A is a projection area on the wafer W toward the discharge direction of the cleaning liquid at the discharge port 40, and the gas discharge position 5A is projected onto the wafer W toward the gas discharge direction of the discharge port 50. It is an area. The distance d between the gas discharge position 5A side interface of the cleaning liquid discharge position 4A and the cleaning liquid discharge position side 5A side interface of the gas discharge position 4A is 9 mm to 15 mm. As described later, the above-mentioned distance d is 12.35 mm. It is most preferable at certain times, and in the present embodiment, each discharge port is set to this size. In this example, the diameter of the discharge port 40 of the cleaning liquid nozzle 4 is 4.3 mm, and the diameter of the discharge port 50 of the gas nozzle 5 is 1.0 mm. The distance d1 between the center of the cleaning liquid supply position and the center of the gas supply position is 15 mm.

  Further, in the figure, reference numeral 5 denotes a control unit comprising a computer, and this control unit 7 is provided with a program for executing each step in the operation to be described later performed by the developing device, and includes a developer supply system 25, a developer nozzle. The control signal for controlling the moving mechanism for moving 23, the cleaning liquid supply system 43, the moving mechanism for moving the cleaning liquid nozzle 4, the driving mechanism 22 for driving the spin chuck 2, and the elevating part 33 of the cup 32. , And output based on the program. The program is stored in a storage medium such as a hard disk, a compact disk, a flash memory, a flexible disk, or a memory card, and is used by being installed in a computer from the storage medium.

  Next, a series of steps for developing the wafer W, which is a substrate, using the developing device and then cleaning the wafer W will be described. First, in a state where the outer cup 31 and the inner cup 32 are in the lowered position and the developer nozzle 23, the cleaning liquid nozzle 4 and the gas nozzle 5 are respectively waiting at predetermined standby positions, a resist is applied to the surfaces thereof, and When the wafer W after immersion exposure is carried in by a substrate transfer means (not shown), the wafer W is delivered to the spin chuck 2 by the cooperative action of the substrate transfer means and a lift pin (not shown). In this example, a highly water-repellent material is used as the resist. Therefore, the static contact angle of water on the surface of the wafer W is, for example, 90 degrees.

  Next, the outer cup 31 and the inner cup 32 are set at the raised position, and the developer is supplied from the developer nozzle 23 onto the wafer W, and the developer is supplied by a known method. In this example, for example, the discharge port 23a of the developer nozzle 23 is set at a position several mm higher than the surface of the wafer W, and then the wafer W is rotated at a rotational speed of 1000 to 1200 rpm, for example, and the developer solution is discharged from the discharge port 23a. The developer nozzle 23 is moved in the rotational radius direction of the wafer W, that is, from the outside of the wafer W toward the center side while discharging D in a belt shape. For example, as schematically shown in FIG. 5, the developer D discharged in a band shape from the discharge ports 23 a is arranged without gaps from the outside to the inside of the wafer W. The developer D is supplied spirally over the entire surface. The developer D spreads outward along the surface of the wafer W by the action of the centrifugal force of the rotating wafer W, and as a result, a thin liquid film is formed on the surface of the wafer W. Then, the soluble portion of the resist is dissolved in the developing solution D, and the insoluble portion that forms the pattern thereafter remains.

  Next, the cleaning liquid nozzle 4 is disposed above the central portion of the wafer W so as to be replaced with the developing liquid nozzle 23, and immediately after the developing liquid nozzle 23 stops supplying the developing liquid, the cleaning liquid R is quickly discharged from the cleaning liquid nozzle 4. Then, the surface of the wafer W is cleaned. Hereinafter, this cleaning process will be described in detail with reference to FIGS. 6 and 7. This cleaning process is performed by the following steps.

  Step 1: As shown in FIG. 6A, the cleaning liquid nozzle 4 is set at a position facing the central portion C of the wafer W and at a height of, for example, 15 mm from the surface of the wafer W, and the spin chuck 2 is set at, for example, 1000 rpm. While rotating at the rotation speed, the cleaning liquid R, for example, pure water is discharged from the cleaning liquid nozzle 4 to the central portion C of the wafer W at a flow rate of, for example, 250 ml / min for 5 seconds, for example. As a result, the cleaning liquid R spreads from the central portion C toward the peripheral edge of the wafer W by centrifugal force, and the developer is washed away by the cleaning liquid R. The central portion C of the wafer W means the center point of the wafer W and its vicinity.

  Step 2: Next, the nozzle arm 44 (see FIG. 2) is moved while the spin chuck 2 is rotated at a rotational speed of 1500 rpm or more, for example, 2000 rpm, so that the cleaning liquid nozzle 4 is moved to the center of the wafer W as shown in FIG. The gas nozzle 5 is moved slightly outward from C, so that the gas nozzle 5 is positioned so as to face the central portion C of the wafer W. At this time, the cleaning liquid nozzle 4 moves at a speed of, for example, 150 mm / second while discharging the cleaning liquid R at a flow rate of, for example, 250 ml / min. Then, the nozzle arm 44 is temporarily stopped, and immediately after the gas nozzle 5 is opposed to the central portion C of the wafer W, a gas, for example, N 2 gas G which is an inert gas is blown onto the central portion C.

  Although the cleaning liquid R is not supplied to the central portion C by moving the cleaning liquid nozzle 4 from the central portion C of the wafer W, the central portion C is thin and thin because the centrifugal force is small. The state is maintained for a while. However, as shown in FIG. 8, when the N2 gas G is blown from the gas nozzle 5, the liquid film is broken, and the dry region 6 where the surface of the wafer W is exposed is expanded by the centrifugal force. At this time, since the surface of the wafer W has a high water repellency with a water contact angle of 90 degrees, the drying region 6 instantly extends to a position where the cleaning liquid R is discharged. A dotted line in FIG. 6B indicates the periphery of the dry region 6, and the inside of the dry region 6 is indicated. The distance d between the gas discharge position 5A side interface of the cleaning liquid discharge position 4A and the cleaning liquid discharge position side 5A side interface of the gas discharge position 4A is 12.35 mm as described above. Since it moves integrally, the dry area | region 6 at this time is circular shape with a diameter of about 25 mm.

  In step 1, the cleaning liquid R is discharged to the central portion C of the wafer W and spreads outside. Therefore, in the region having a diameter of 30 mm, the amount of the cleaning liquid R per unit area is large, and centrifugal force is also acting. Since the cleaning liquid R thus collided with the central portion C and spreads outward due to the impact, the cleaning effect is great. For this reason, even if the drying region 6 expands instantaneously, the phenomenon shown in FIG. 27 (b) can be said to be completely absent from the evaluation test described later, and the cleaning liquid R in the recesses of the pattern is surely discharged. ing.

  Step 3: After the drying region 6 is formed, the gas discharge is terminated, and then the cleaning liquid nozzle 4 and the gas nozzle 5 are moved integrally toward the periphery of the wafer W by the nozzle arm 44 as shown in FIG. The time from the supply start to the stop of the gas for forming the dry region 6 is, for example, 0.5 seconds.

  In step 3, the cleaning liquid R is discharged from the cleaning liquid nozzle 4 while the wafer W is rotating. The moving speed of the cleaning liquid nozzle 4 is set to a speed lower than the speed at which the dry region 6 spreads outward, for example, 5 mm / second. When the cleaning liquid is discharged onto the central portion C of the wafer W by the cleaning liquid nozzle 4 and then only the N2 gas G is sprayed without discharging the cleaning liquid, the drying area 6 expands outward. The “speed at which 6 spreads outward” is the speed in this case. Since the surface of the wafer W has a high water repellency, the speed of the drying region 6 is large as described above. Therefore, if the moving speed of the cleaning liquid nozzle 4 is made larger than the speed of the drying region 6, FIG. As shown, the cleaning liquid R remains. In step 3, the rotational speed of the wafer W is controlled so that the centrifugal force due to the rotation of the wafer W is constant in calculation at each discharge position of the cleaning liquid R as shown in FIG. The rotation speed f1 at the start of step 3 is, for example, 2000 rpm.

  The reason for controlling the number of revolutions in this way is that the amount of the cleaning liquid R supplied per unit area on the wafer W is made uniform in the plane of the wafer W, so that high cleaning is performed even in a region off the central portion C of the wafer W. This is to obtain an effect. If such an effect can be obtained, the rotation speed of the wafer W becomes closer to the center of the wafer W even if the centrifugal force due to the rotation of the wafer W is not constant at each discharge position of the cleaning liquid R. In other words, the rotational speed of the wafer W may be controlled so that the rotational speed of the wafer W decreases as the supply position of the cleaning liquid R is closer to the periphery of the wafer W.

  The rotation speed f1 at the start of step 3 is preferably, for example, 2000 rpm to 3000 rpm. If the rotation speed is higher than 3000 rpm, problems such as mist occur. Processing time becomes longer. The nozzle moving speed in Step 3 is preferably as fast as possible in order to shorten the processing time. However, if it is too fast, the cleaning effect is reduced, and it is preferable not to exceed 10 mm / second.

  When the center of the cleaning liquid nozzle 4 reaches a position slightly closer to the center from the periphery of the wafer W, for example, a position 2 to 10 mm away from the periphery of the wafer W toward the center side (FIG. 7A), the cleaning liquid from the cleaning liquid nozzle 4 is reached. The discharge of R is stopped, and the wafer W is kept rotating (FIG. 7B). If the cleaning liquid R is discharged from the cleaning liquid nozzle 4 to the periphery of the wafer W, the cleaning liquid R discharged onto the surface of the wafer W jumps outward and returns to the surface of the wafer W as a mist. It is preferable to stop the discharge of the cleaning liquid R slightly before reaching the periphery. In the step of moving the cleaning liquid nozzle 4, the gas may be discharged together with the cleaning liquid. In this case, the timing of stopping the discharge of the N 2 gas G from the gas nozzle 5 may be the same as the timing of stopping the discharge of the cleaning liquid R, but may be before or after the discharge of the cleaning liquid R is stopped.

  Step 4: After stopping the discharge of the cleaning liquid R from the cleaning liquid nozzle 4, the wafer W is rotated at the same rotation speed (in this example, 2000 rpm). As a result, the dry region 6 spreads outward and the dry region 6 spreads to the periphery of the wafer W. In this example, the droplets on the wafer W are spun off by centrifugal force while the rotation speed of the wafer W is set to 2000 rpm. And dry. The cleaning liquid nozzle 4 and the gas nozzle 5 are returned to the standby position.

  The developed wafer W is formed with a concave portion that is a pattern, and the concave portion becomes hydrophilic, and there is a portion where the contact angle of the surface of the wafer W decreases. The object of the present invention is a substrate having a hydrophobic surface with a water contact angle of 85 degrees or more, and in this example, has a hydrophobic surface with a static contact angle of water of 85 degrees or more before development processing. The substrate cleaning process is shown. When cleaning is performed after the development process for supplying the developer to the substrate, the static contact angle of water on the substrate is 85 degrees or more means that the static contact angle of water on the substrate before the development process is 85 degrees or more. Show. For the substrate surface where the static contact angle of water was 85 degrees or more before the development processing due to the change of the resist surface state depending on the developer, the static contact angle of the resist is more than 85 degrees during cleaning. However, since the cleaning process in this case must be performed immediately after the development process, it is difficult to accurately measure the static contact angle after the development process and before the cleaning process. Thus, the static contact angle is defined.

  In the series of steps 1 to 4 described above, the CPU reads a program stored in the memory of the control unit 7 and outputs a control signal for operating each of the mechanisms described above based on the read command. It is executed by.

  According to the above-described embodiment, the central portion of the wafer W is subjected to spin cleaning after developing the wafer W having a highly water-repellent resist surface with a water contact angle of 85 degrees or more on the surface. After supplying the cleaning liquid R to C, the supply position of the cleaning liquid R is moved from the central portion to the eccentric position, and gas is supplied from the gas nozzle 5 to the central portion C of the wafer W, and the gas discharge position of the cleaning liquid discharge position on the wafer W The dry area 6 of the cleaning liquid R is generated by supplying the side interface and the distance between the gas discharge position on the wafer W and the cleaning liquid discharge position side interface in a state of 9 to 15 mm, and then the wafer W is rotated. The supply position of the cleaning liquid R is moved toward the periphery of the wafer W at a speed slower than the speed at which the drying region 6 spreads outside. For this reason, a high cleaning effect can be obtained, and as will be apparent from an evaluation test described later, development defects can be reduced to almost none, greatly contributing to the improvement of the yield, and performing cleaning in a short time. be able to. Further, the rotational speed of the wafer W is controlled so that the rotational speed of the wafer W becomes higher as the supply position of the cleaning liquid R is closer to the periphery of the wafer W, whereby the amount of the cleaning liquid R supplied per unit area on the wafer W is controlled. If they are aligned in the plane of the wafer W, a high cleaning effect can be obtained even in a region off the center of the wafer W. Therefore, such a technique is extremely effective for a technique that supports immersion exposure using a resist having high water repellency without using a protective film.

  Here, in the present invention, when the dry region 6 is formed in Step 2, “the distance between the gas discharge position side interface of the cleaning liquid discharge position on the wafer W and the cleaning liquid discharge position side interface of the gas discharge position on the wafer W”. It is a requirement that gas is discharged to the center of the wafer W in a state where d is set to 9 mm to 15 mm, and the present invention is meaningful when an appropriate value of the distance d is found from an experiment described later. .

[Second Embodiment]
In this embodiment, the cleaning liquid nozzle 4 and the gas nozzle 5 are configured to be independently movable by separate nozzle arms. Then, the cleaning liquid nozzle 4 discharges the cleaning liquid to the central portion C of the wafer W, and then the cleaning liquid nozzle 4 is moved slightly outward from the central portion C of the wafer W and the gas nozzle 5 is opposed to the central portion C of the wafer W. Then, N2 gas is supplied from the gas nozzle 5 to the central portion C to form a dry region 6. Thereafter, the cleaning liquid nozzle 4 is moved to the vicinity of the peripheral edge of the wafer W in a state where the cleaning liquid is discharged (FIGS. 10A and 10B), and then the discharge of the cleaning liquid is stopped and the wafer W is dried ( FIG. 10 (c)). On the other hand, after the gas nozzle 5 supplies N2 gas to the central portion C to form the dry region 6, the gas nozzle 5 stops discharging N2 gas.

The separation distance between the cleaning liquid nozzle 4 and the gas nozzle 5 at the time of FIG. 6B is the same as that in the first embodiment. The gas nozzle 5 is located above the central portion C in FIG. 10 after discharging the N2 gas to the central portion C of the wafer W to form the dry region 6, but it may be returned to the standby position. . Also in this embodiment, the same effect as the first embodiment can be obtained.
In the second embodiment, after the operation shown in FIGS. 6A and 6B is performed, N2 gas is discharged from the gas nozzle 5 to the central portion C of the wafer W when the cleaning liquid nozzle 4 moves. You may continue.

[Third Embodiment]
By the way, since the developer and the cleaning liquid are supplied, the atmosphere in the cup 31 is high in humidity. Especially, immediately after the cleaning liquid is supplied, the surrounding atmosphere supplied with the cleaning liquid nozzle is high in humidity. Therefore, in step 3 of the first embodiment, as the gas nozzle 5 moves from the central portion C to the peripheral portion of the wafer following the cleaning liquid nozzle 4, moisture in the surrounding atmosphere adheres to the surface of the gas nozzle 5. There is a possibility that a droplet is formed, the droplet falls from the gas nozzle 5 to the drying region 6 and enters into the concave portion formed there, thereby causing a development defect. Therefore, an embodiment capable of suppressing such development defects due to falling droplets will be described.

  11 shows a developing device 70 configured in the same manner as the developing device in FIG. 1. The same reference numerals as those in FIG. 1 are assigned to the same components as those in the developing device in FIG. The difference between the developing device 70 and the developing device of FIG. 1 will be mainly described. The first cleaning liquid nozzle 71 provided in the developing device 70 corresponds to the cleaning liquid nozzle 4 and has the same configuration as the cleaning liquid nozzle 4. Further, the developing device 70 is provided with a second cleaning liquid nozzle 72 that supplies the cleaning liquid to the wafer W independently of the first cleaning liquid nozzle 71. Similarly to the cleaning liquid nozzle 71, the second cleaning liquid nozzle 72 is connected to a cleaning liquid supply system 74 configured similarly to the cleaning liquid supply system 43 through a cleaning liquid supply path 73.

  As shown in FIG. 12A, the cleaning liquid nozzles 71 and 72 and the gas nozzle 5 are fixed to the nozzle arm 44 via the nozzle holding portion 41, and the radial direction of the wafer W is the same as in the first embodiment. Are configured to move integrally with each other. In the figure, reference numerals 71a and 72a denote cleaning liquid discharge ports of the cleaning liquid nozzles 71 and 72, respectively, which are configured to discharge the cleaning liquid R vertically downward as shown in FIG. 12 (b).

  The distance d between the gas discharge position side interface of the cleaning liquid discharge position discharged from the cleaning liquid nozzle 71 onto the wafer W and the cleaning liquid discharge position side interface of the gas discharge position discharged from the gas nozzle 5 onto the wafer W is the first embodiment. Is set to 9 mm to 15 mm. The distance d2 between the center P1 of the discharge port 50 of the gas nozzle 5 and the center P2 of the discharge port 72a of the second cleaning liquid nozzle 72 in the moving direction of the nozzles 71, 72 and 5 is set to 17.9 mm, for example. A distance d3 between the center P1 and the center P2 in a direction orthogonal to the moving direction of the nozzle is, for example, 15 mm. The cleaning liquid nozzle 71a and the gas nozzle 5 are arranged in parallel with the movement direction of each nozzle so that the cleaning liquid R and the N2 gas G can be discharged to the central portion of the wafer W, respectively. The angle θ formed with the direction in which the cleaning liquid nozzles 72 are arranged is, for example, 40 °. Although the layout of each nozzle is not limited to this example, when supplying the cleaning liquid from the second cleaning liquid nozzle 72 to the outer edge position of the drying region 6 as described later, the supply position of the cleaning liquid from the second cleaning liquid nozzle 72 Each nozzle is arranged so that the distance from the center of the wafer W is closer to the distance between the center of the wafer W and the gas nozzle 5. “The distance between the central portion of the wafer W (substrate) and the discharge position of the cleaning liquid R from the second cleaning liquid nozzle 72 is closer than the distance between the central portion of the wafer W and the projection position of the gas nozzle 5 on the wafer W”. Includes that these distances are the same. That is, the positions of the second cleaning liquid nozzle 72 and the gas nozzle 5 are positions where the droplets dropped from the gas nozzle are removed by the cleaning liquid R from the second cleaning liquid nozzle 72.

  Subsequently, the state of each step in which cleaning is performed using the developing device 70 will be described with reference to FIGS. 13 and 14. FIG. 13 shows the movement of each of the cleaning liquid nozzles 71 and 72 and the gas nozzle 5 and the fluctuation of the drying region 6, and FIG. 14 shows how the cleaning liquid and gas are discharged from each nozzle. A chain line in FIG. 13 indicates the diameter of the wafer W, and a chain line in FIG. 14 indicates the rotation center axis of the wafer W.

  Step S1: After supplying the developer as in the first embodiment, as shown in FIG. 13A, the first cleaning liquid nozzle 71 is opposed to the central portion C of the wafer W and from the surface of the wafer W. For example, while setting the position at a height of 15 mm and rotating the spin chuck 2 at a rotational speed of 1000 rpm, for example, the cleaning liquid R is supplied from the cleaning liquid nozzle 71 to the center C of the wafer W at a flow rate of 250 ml / min, for example, for 5 seconds. It discharges (FIG. 14A). Then, the cleaning liquid R spreads from the center C of the wafer W toward the peripheral edge due to centrifugal force, and the developer is washed away by the cleaning liquid R.

  Step S2: Next, while rotating the spin chuck 2 at a rotation speed of 1500 rpm or more, for example, 2000 rpm, the cleaning liquid nozzle 71 is moved slightly outward from the central portion C of the wafer W as shown in FIG. The gas nozzle 5 is moved so as to face the central portion C of the wafer W by moving from the central portion of the wafer W. At this time, the first cleaning liquid nozzle 71 moves at a speed of, for example, 150 mm / second while discharging the cleaning liquid R at a flow rate of, for example, 250 ml / min. Immediately after the gas nozzle 5 faces the central portion C of the wafer W, a gas, for example, N2 gas G, which is an inert gas, is blown onto the central portion C, and a dry region 6 is formed as in the first embodiment. The dry region 6 extends to a position where the cleaning liquid R is discharged by the first cleaning liquid nozzle 71 (FIG. 13B).

  Step S3: The gas discharge is terminated, for example, after 0.5 seconds from the start of the gas discharge, and the discharge of the cleaning liquid R from the first cleaning nozzle 71 is stopped substantially simultaneously with that, and then, as shown in FIG. The first cleaning liquid nozzle 71 and the gas nozzle 5 are moved from the peripheral edge of the wafer W, and the second cleaning liquid nozzle 72 is moved onto the diameter of the wafer W (14 (c)). The moving speed at this time corresponds to the position of the outer edge of the dry region 6 that spreads the center of the wafer W when the discharge position of the cleaning liquid R onto the wafer W of the second cleaning liquid nozzle 72 is positioned on the diameter of the wafer W. The speed at which the cleaning liquid can be supplied from the second cleaning liquid nozzle 72 is, for example, 150 mm / second.

  Step S4: When each nozzle continues to move and the discharge position of the cleaning liquid R supplied from the second cleaning liquid nozzle 72 to the wafer W is positioned on the diameter of the wafer W as described above, the cleaning liquid nozzle 72 moves to the wafer W. The cleaning liquid R is discharged to the outer edge position of the dry region 6 at, for example, 250 mL / second (FIGS. 13D and 14D). In this case, the “outer edge position of the drying region” includes a case where the discharge of the cleaning liquid is started at a position inside or outside a few millimeters, for example, about 2 mm from the outer edge position within a range not affecting the cleaning effect. As such an example, for example, a case where the discharge position of the cleaning liquid slightly deviates from the outer edge position of the drying region based on the operation timing of the nozzle drive mechanism and the timing of the expansion of the drying region.

  Step S5: As shown in FIG. 13 (e) and FIG. 14 (e), the cleaning liquid nozzles 71 and 72 and the gas nozzle 5 continue toward the peripheral edge of the wafer W, and the drying area 6 is slower than the speed at which it spreads outward. For example, it moves at 5 mm / second. Thus, during the movement of each nozzle, droplets L are formed on the cleaning liquid nozzle 71 and the gas nozzle 5 as shown in FIG. 15, and even if the droplet L falls on the wafer W, the cleaning liquid nozzle 71 and the gas nozzle Since 5 is moving outside the drying area 6, the dropped liquid droplet L is washed away by the cleaning liquid R supplied from the cleaning liquid nozzle 72. Accordingly, it is possible to prevent the droplet L from entering into the recess formed on the surface of the wafer W and remaining as it is and causing development defects.

  Step S6: When the discharge position of the cleaning liquid from the second cleaning liquid nozzle 72 reaches a position slightly closer to the center from the periphery of the wafer W, for example, a position 2 to 10 mm away from the periphery of the wafer W toward the center (FIG. 13 ( f)), the discharge of the cleaning liquid R from the second cleaning liquid nozzle 72 is stopped (FIG. 14F). Then, the wafer W is continuously rotated at the same rotation speed (in this example, 2000 rpm) to widen the drying region 6 toward the outside. After the drying region 6 has spread to the periphery of the wafer W, in this example, While the rotation speed of the wafer W is set to 2000 rpm, the droplets on the wafer W are shaken off by a centrifugal force to be dried.

  Also in the third embodiment, after supplying the cleaning liquid R to the central portion C of the wafer W, the supply position of the cleaning liquid R is moved from the central portion C to the eccentric position, and the central portion C of the wafer W is moved to the central portion C of the wafer W. Supply in a state where the distance between the cleaning liquid discharge position side interface of the gas discharge position and the gas discharge position side interface of the cleaning liquid discharge position is 9 mm to 15 mm to generate the dry region 6 of the cleaning liquid R, and then rotate the wafer W The supply position of the cleaning liquid R is moved toward the periphery of the wafer W at a speed slower than the speed at which the drying area 6 spreads outside. For this reason, a high cleaning effect can be obtained as in the first embodiment. Further, after the drying region 6 is formed and the cleaning liquid is supplied from the second cleaning nozzle 72, the first cleaning nozzle 71 and the gas nozzle 5 move outside the outer edge of the drying region 6, so that these nozzles Occurrence of development defects due to dripping droplets is suppressed.

[Fourth Embodiment]
The cleaning method of the fourth embodiment is performed using the same apparatus as that used in the first embodiment, and the cleaning liquid nozzle 4 and the gas nozzle 5 move together. The movement of each cleaning nozzle 4 and gas nozzle 5 will be described with reference to FIG. 16. For convenience, the horizontal direction in the figure, which is the movement direction of each nozzle, is called the X direction, and the side on which the cleaning liquid nozzle 4 is arranged (see FIG. 16 (right side in FIG. 16) and the side where the gas nozzle 5 is disposed (left side in FIG. 16) are defined as + X side and −X side, respectively.

  First, after supplying the developer as in the first embodiment, the cleaning liquid R is discharged from the cleaning liquid nozzle 4 to the central portion C of the wafer W (FIG. 16A), and the cleaning liquid nozzle is discharged in a state where the cleaning liquid R is discharged. 4 and the gas nozzle 5 are moved in the + X direction, and the gas nozzle 5 is positioned so as to face the central portion C of the wafer W. Then, an N2 gas G is supplied from the gas nozzle 5 to the central portion C to form a dry region 6 (FIG. 16B). After a predetermined time has elapsed from the start of gas supply, supply of N2 gas G and supply of cleaning liquid R are stopped, and cleaning liquid nozzle 4 and gas nozzle 5 are moved in the -X direction faster than the speed at which drying region 6 spreads wafer W. (FIG. 16C). The moving speed of the nozzles 4 and 5 at this time is, for example, 150 mm / sec.

  Then, the discharge of the cleaning liquid R is resumed so that the cleaning liquid nozzle 4 passes over the central portion C of the wafer W and then the cleaning liquid R is supplied to the outer edge position in the drying region 6 (FIG. 16D). ). Thereafter, with the cleaning liquid R being discharged from the cleaning liquid nozzle 4, the cleaning liquid nozzle 4 and the gas nozzle 5 are moved in the -X direction at a speed slower than the speed at which the drying region 6 spreads outward, for example, 5 mm / sec. In accordance with the movement, the drying region 6 expands outward (FIG. 16 (e)). Thereafter, when the cleaning liquid nozzle 4 moves to the vicinity of the peripheral edge of the wafer W, the discharge of the cleaning liquid R is stopped, and the wafer W is dried in the same manner as in Step 4 of the first embodiment.

  Also in the fourth embodiment, since the nozzle arrangement is the same as in the first embodiment, the same effect as in the first embodiment is obtained. Further, in the fourth embodiment, after the N2 gas is discharged, the gas nozzle 5 is arranged in the outer region of the drying region 6, and when the cleaning liquid nozzle 4 moves toward the periphery of the wafer W while discharging the cleaning solution, the gas nozzle 5 is located in the drying region 6. Since it moves outside, even if a droplet falls from the gas nozzle 5 onto the wafer W, it can be prevented from falling into the drying region 6. Therefore, the occurrence of development defects can be more reliably suppressed. In the fourth embodiment, after the drying region 6 is formed, the nozzles 4 and 5 pass over the drying region 6, so that droplets adhere to each nozzle during movement, and the droplets enter the drying region 6. Although there is a risk of falling, the formation of the dry region 6 remains at the center of the wafer W where the centrifugal force is small when the nozzle moves in this way, and the movement of the nozzles 4 and 5 moving on the dry region 6 Since the distance can be suppressed, the drop of the droplets to the dry region 6 can be suppressed as compared with the first embodiment. However, the third embodiment is preferable because development defects due to the droplets can be more reliably suppressed.

  In this embodiment, the nozzle standby area may be configured as shown in FIGS. 17 (a) and 17 (b) in order to suppress the drop of liquid during nozzle movement. In this example, the standby region 46 is configured as a space in the container 4A whose upper side is open, and a drying gas is blown into the container 4A to dry the nozzle 4 while the nozzle 4 is waiting. A nozzle 47 and an exhaust pipe 48 for exhausting the dry gas supplied into the standby area 46 are provided. The standby area 46 is thus configured, and after cleaning and drying one wafer W, the nozzle 4 is dried while the cleaning liquid nozzle 4 is waiting in the standby area 46, thereby processing the next wafer. It is possible to suppress the droplets from dropping from the cleaning liquid nozzle 4 into the drying region 6. 4B is a standby area of the gas nozzle 5 provided so as to be adjacent to the standby area 46. The gas nozzle 5 is configured in the same manner as the standby area 46, and the gas nozzle 5 is dried while the gas nozzle 5 is on standby. In other embodiments, the standby areas 46 and 4B may be configured in this way. Further, in the standby areas 46 and 4B, instead of providing the drying nozzle 47, a heater may be provided, and the cleaning liquid nozzle 4 and the gas nozzle 5 may be dried by the heat of the heater.

[Fifth Embodiment]
Next, a fifth embodiment that is a modification of the fourth embodiment will be described. The cleaning process performed in this embodiment is configured in substantially the same manner as the developing device of the first embodiment. However, as shown in FIGS. 18A and 18B, the cleaning nozzle 4 has an X-direction axis as a rotation center. It can be tilted in the Y direction that is orthogonal to the X direction.

  Next, the cleaning method of the fifth embodiment will be described with reference to FIG. First, as in the fourth embodiment, the cleaning liquid R is discharged from the cleaning liquid nozzle 4 in which the discharge direction of the cleaning liquid is directed vertically downward onto the central portion C of the wafer W after the developer is supplied. Subsequently, with the cleaning liquid R being discharged, the cleaning liquid nozzle 4 and the gas nozzle 5 are moved in the + X direction, the gas nozzle 5 is positioned so as to face the central portion C of the wafer W, and N2 gas G is supplied to the center of the wafer W. The dry region 6 is formed in the part C (FIG. 19A).

  Thereafter, the supply of the N 2 gas G and the supply of the cleaning liquid R are stopped, and the projection area 49 of the discharge port 40 of the cleaning liquid nozzle 4 onto the wafer W is not positioned in the dry area 6 as shown in FIG. Next, the cleaning liquid nozzle 4 is tilted in the Y direction, and then the cleaning liquid nozzle 4 and the gas nozzle 5 are moved in the −X direction faster than the speed at which the drying region 6 spreads the wafer W as in the fourth embodiment (FIG. 19 ( b)).

  Then, after the cleaning liquid nozzle 4 passes over the central portion C of the wafer W and is positioned slightly outside the outer edge of the drying region 6, for example, the inclination of the cleaning liquid nozzle 4 changes in order to supply the cleaning liquid vertically downward, Thereafter, the discharge of the cleaning liquid is resumed so that the cleaning liquid R is supplied to the outer edge position of the drying region 6 (FIG. 19C). Thereafter, in the state where the cleaning liquid R is discharged from the cleaning liquid nozzle 4 as in the fourth embodiment, the cleaning liquid nozzle 4 and the gas nozzle 5 are slower than the speed at which the drying region 6 spreads outward, for example, 5 mm / sec. The wafer W is dried in the same manner as in Step 4 of the first embodiment when the cleaning liquid nozzle 4 is moved to the vicinity of the peripheral edge of the wafer W.

  The fifth embodiment has the same effect as that of the fourth embodiment. Further, after the dry region 6 is formed, when the gas nozzle 5 is disposed outside the dry region 6, the projection of the discharge port 40 is projected. By tilting the cleaning liquid nozzle 4 so that the area is directed to the outside of the drying area 6, it is possible to suppress the droplet L from falling into the drying area 6 from the cleaning liquid nozzle 4. In addition, when the gas nozzle 5 moves on the drying region 6, the inclination of the gas nozzle 5 may be changed similarly to the cleaning liquid nozzle 4 to prevent the droplet L from falling into the drying region 6.

[Sixth Embodiment]
Next, a sixth embodiment, which is another modification of the fourth embodiment, will be described. The developing device used in the sixth embodiment is configured in substantially the same manner as the device of the first embodiment, but the cleaning liquid nozzle 4 is obliquely arranged as shown in FIGS. 20 (a) and 20 (b). 41. However, the supply position of the cleaning liquid R to the wafer W can be moved on the diameter of the wafer W by the movement of the cleaning liquid nozzle 4 as in the other embodiments. Further, the distance d between the gas discharge position side interface of the cleaning liquid discharge position on the wafer W and the cleaning liquid discharge position side interface of the gas discharge position on the wafer W shown in FIG. Is set to the same size as

  The cleaning liquid nozzle 4 is provided obliquely in this manner when the cleaning process is performed in the same manner as in the fourth embodiment, and after the drying region 6 is formed, the cleaning liquid nozzle 4 and the gas nozzle 5 are moved in the −X direction. Furthermore, when the projection area 4a of the cleaning liquid nozzle 4 on the surface of the wafer W moves outside the drying area 6, and the droplet L falls from the cleaning liquid nozzle 4 as shown in FIG. The purpose is to drop the droplet L outside the drying region 6. Accordingly, the angle of the cleaning liquid nozzle 4 with respect to the horizontal axis and the distance in the Y-axis direction between the cleaning liquid nozzle 4 and the gas nozzle 5 depend on the speed at which the drying region 6 spreads and the moving speed of the nozzles 4 and 5 in the −X direction. It is designed appropriately.

  The cleaning process of the sixth embodiment is performed in the same manner as the cleaning process of the fourth embodiment. After supplying the N2 gas G from the gas nozzle 5 and forming the dry region 6 in the central portion C of the wafer W (FIG. 21A), the supply of the N2 gas G and the supply of the cleaning liquid R are stopped, and the dry region 6 The cleaning liquid nozzle 4 and the gas nozzle 5 are moved in the −X direction faster than the speed at which the wafer 6 spreads the wafer W (FIG. 21B), and thereafter, the wafer W is supplied from the cleaning liquid nozzle 4 as in the fourth embodiment. When the supplied position of the cleaning liquid passes over the central portion C of the wafer W and is positioned slightly outside the drying region 6, for example, the cleaning liquid R is discharged from the cleaning liquid nozzle 4 toward the wafer W (FIG. 21C). ). Thereafter, the cleaning liquid nozzle 4 is moved to the periphery of the wafer W.

  If the cleaning is performed in this way, the nozzles 4 and 5 are moved in the −X direction on the drying area 6 until the cleaning liquid R is supplied after the drying area 6 is formed. In addition, since the gas nozzle 5 moves outside the drying area 6 after resuming discharge of the cleaning liquid, the liquid droplet L can be suppressed from falling into the drying area 6 from the gas nozzle 5. .

  Also in these second to sixth embodiments, the rotational speed of the wafer W may be controlled in accordance with the supply position of the cleaning liquid as in the first embodiment. In addition, the operation of each unit of the developing device of each embodiment is controlled based on a control signal transmitted from the control unit 7, and the above-described cleaning process is performed.

  The substrate cleaning apparatus of the present invention is a substrate using a highly water-repellent resist in a pattern forming system that performs immersion exposure, and can be used publicly for cleaning a substrate after development. It is also suitable for cleaning a substrate before immersion exposure or a substrate after immersion exposure and before development. Specifically, it may be performed before immersion exposure on the substrate in which a highly water-repellent protective film is formed on the resist of the substrate or a substrate on which a highly water-repellent resist is applied without forming a protective film. In addition, there are cases where the protective film is removed with a chemical solution after immersion exposure and the chemical solution is washed, or the droplets are removed after immersion exposure on a substrate coated with a highly water-repellent resist without forming a protective film. Can be mentioned.

  An example in which the cleaning apparatus of the present invention is applied to a pattern forming system that performs immersion exposure will be briefly described below with reference to FIGS. In this system, an exposure apparatus is connected to a coating / developing apparatus, and B1 in the drawing includes a mounting portion 120a for carrying in and out a carrier C1 in which, for example, 13 wafers W are hermetically stored. A carrier station 120, an opening / closing part 121 provided on a wall surface in front of the carrier station 120, and delivery means A 1 for taking out the wafer W from the carrier 2 through the opening / closing part 121 are provided.

  A processing unit B2 surrounded by a casing 122 is connected to the back side of the carrier mounting unit B1, and the processing unit B2 is a shelf unit in which heating / cooling units are arranged in multiple stages in order from the front side. Main transfer means A2 and A3 for transferring the wafer W between the units U1, U2 and U3 and the liquid processing units U4 and U5 are alternately arranged. The main transport means A2 and A3 have one surface on the shelf units U1, U2 and U3 arranged in the front-rear direction as viewed from the carrier mounting portion B1, and one surface on the right liquid processing unit U4 and U5 side which will be described later. It is placed in a space surrounded by a partition wall 123 composed of a side and a back surface portion forming one side of the left side. In the figure, reference numerals 124 and 125 denote temperature / humidity adjusting units including a temperature adjusting device for processing liquid used in each unit, a duct for adjusting temperature / humidity, and the like.

  The liquid processing units U4 and U5 are, for example, as shown in FIG. 23, a coating unit (COT) 27, a developing unit (DEV) 128, and a reflection processing prevention film forming unit on a chemical solution storage section 126 such as a resist solution and a developing solution. BARC and the like are stacked in a plurality of stages, for example, five stages. The developing unit (DEV) 128 also serves as the cleaning device of the first embodiment. In addition, the above-described shelf units U1, U2, and U3 are configured such that various units for performing pre-processing and post-processing of the processing performed in the liquid processing units U4 and U5 are stacked in a plurality of stages, for example, 10 stages. The combination includes a heating unit for heating (baking) the wafer W, a cooling unit for cooling the wafer W, and the like.

  An exposure unit B4 is connected to the back side of the shelf unit U3 in the processing unit B2 via an interface unit B3. As shown in detail in FIG. 22, the interface unit B3 is composed of a first transfer chamber 130A and a second transfer chamber 130B provided in the front and rear between the processing unit B2 and the exposure unit B4. A first substrate transport unit 131A and a second substrate transport unit 131B are provided respectively. In the first transfer chamber 130A, a shelf unit U6, a buffer cassette CO, and a substrate cleaning apparatus 140 of the present invention are provided. The shelf unit U6 has a configuration in which a heating unit (PEB) that performs PEB processing of the exposed wafer W, a highly accurate temperature control unit having a cooling plate, and the like are stacked vertically.

  The flow of the wafer W in the above system will be briefly described. First, when the carrier C1 storing the wafer W from the outside is mounted on the mounting table 120a, the lid of the carrier C1 is removed together with the opening / closing portion 121, and the wafer W is taken out by the transfer means A1. Then, the wafer W is transferred to the main transfer means A2 through a transfer unit that forms one stage of the shelf unit U1, and on one shelf in the shelf units U1 to U3, an antireflection film is formed or a substrate is formed by the cooling unit. Temperature adjustment is performed.

  Thereafter, the wafer W is carried into the coating unit (COT) 27 by the main transfer means A2, and a resist film is formed on the surface of the wafer W. Thereafter, the wafer W is unloaded by the main transfer means A2, loaded into the heating unit, and baked at a predetermined temperature.

  The wafer W that has been baked is then cooled by the cooling unit, and then transferred to the interface unit B3 via the delivery unit of the shelf unit U3, and then transferred into the exposure unit B4 via the interface unit B3. Is done. In the case where a protective film for immersion exposure is applied on the resist film, after cooling by the cooling unit, a chemical solution for protective film is applied in a unit (not shown) in the processing section B2. Thereafter, the wafer W is carried into the exposure unit B4 and subjected to immersion exposure. However, before the immersion exposure, the wafer W may be cleaned by a cleaning apparatus (not shown) provided in the interface unit B3.

  Thereafter, the wafer W that has been subjected to immersion exposure is taken out from the exposure unit B4 by the second substrate transfer unit 131B, and water droplets on the surface of the substrate are removed by the substrate cleaning device 140 of the present invention, and then the shelf unit U6. It is carried in to the heating unit (PEB) which constitutes one stage.

  Thereafter, the wafer W is unloaded from the heating unit 138 by the substrate transfer unit 131A and transferred to the main transfer means A2. Then, it is carried into the developing unit 128 by this main transport means A2. In the developing unit 128, the substrate is developed with a developer and further washed. Thereafter, the wafer W is heated by the heating unit and then returned to the original carrier C1 on the mounting table 120a.

[Evaluation test]
(Wafer and equipment used in the experiment)
A resist having high water repellency was applied on the wafer, followed by immersion exposure, and further developed with a developing device to form a resist pattern having a recess line width of 150 nm. The contact angle of water on the resist surface after forming the resist on the entire wafer surface was 92 degrees. The cleaning device incorporated in the developing device is the same as that of the first embodiment, except that the cleaning liquid nozzle 4 and the gas nozzle 5 are configured to be independently movable and controlled. Since the contact angle slightly changes depending on each part of the wafer W, the contact angle here is an average value of the contact angles of the respective parts on the surface of the wafer W.

(Evaluation test 2)
In step 1 in the first embodiment, the discharge flow rate of the cleaning liquid to the center of the wafer is 250 ml / second, and the rotation speed of the wafer is 500 rpm. In step 2 (FIGS. 6B and 8), the distance d between the gas discharge position side interface at the cleaning liquid discharge position and the cleaning liquid discharge position side interface at the gas discharge position was set to 12.35 mm. Further, in step 2, the wafer rotation speed f1 (see FIG. 9) when the cleaning liquid nozzle 4 starts to move toward the periphery of the wafer is set to 3000 rpm, and the moving speed of the cleaning liquid nozzle 4 is set to 6.5 mm / second. The other parameters are the values described in the first embodiment.
When the wafer was cleaned in this way and then dried and development defects were measured, there was only one defect at the center of the wafer and three on the entire surface.

(Evaluation Test 3)
The distance d between the gas discharge position side interface at the cleaning liquid discharge position and the cleaning liquid discharge position side interface at the gas discharge position is set to be changed for each wafer, and the other conditions are the same as in the evaluation test 1. The number of defects (number of particles) of each wafer W after the cleaning process was measured. FIG. 24 is a graph showing the results, and the number of defects when the distance d between the interfaces is 7.35 mm, 9.85 mm, 12.35 mm, 14.85 mm, 17.35 mm, 19.85 mm, 22.35 mm. Are 810, 430, 25, 422, 891, 1728, and 2162, respectively. If the distance d is too small, problems such as the dry region 6 not being formed or drying being delayed occur, and if the distance d is too large, drying occurs instantaneously in a wide area, increasing the number of defects. Since the number of defects is preferably 500 or less in practice, the range of the distance d effective for suppressing the number of defects is 9 mm to 15 mm, considering the results of this experiment and the errors in assembly and processing of the apparatus. It can be said that.

(Evaluation Test 3)
After the N2 gas was discharged from the gas nozzle 5 to form the dry region 6, cleaning was performed in the same manner as in the evaluation test 1 except that the cleaning liquid nozzle 4 was moved toward the peripheral edge of the wafer at a constant speed of 10 mm / second. The number of defective portions was 303, and there were many defective portions as compared with the evaluation test 1 in which the moving speed of the cleaning liquid nozzle 4 was 6.5 mm / second. This indicates that the nozzle moving speed affects the number of defects.

It is a longitudinal cross-sectional view which shows the board | substrate cleaning apparatus combined with the developing device concerning the 1st Embodiment of this invention. It is a top view which shows the board | substrate cleaning apparatus concerning the said 1st Embodiment. It is a perspective view of a cleaning liquid nozzle, a gas nozzle, and its surrounding components. It is a side view which shows the washing | cleaning-liquid nozzle and gas nozzle which are used for the board | substrate cleaning apparatus concerning the said 1st Embodiment in a partial cross section. It is a perspective view which shows an example of the method of supplying a developing solution with respect to a wafer. It is explanatory drawing which shows a mode that the wafer after image development is wash | cleaned in the said 1st Embodiment. It is explanatory drawing which shows a mode that the wafer after image development is wash | cleaned in the said 1st Embodiment. It is explanatory drawing which shows a mode that a dry area spreads by discharging N2 gas to the center part of a wafer. FIG. 6 is a relationship diagram illustrating a relationship between a cleaning liquid discharge position and a rotation speed of a wafer. It is explanatory drawing which shows a mode that the wafer after image development is wash | cleaned in the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the board | substrate washing | cleaning apparatus combined with the developing device which concerns on the 3rd Embodiment of this invention. It is a block diagram of the nozzle provided in the said board | substrate cleaning apparatus. It is explanatory drawing which showed the position of the nozzle at the time of wafer cleaning in 3rd Embodiment. It is explanatory drawing which shows a mode that the wafer after image development is wash | cleaned in the 3rd Embodiment of this invention. It is a side view of the nozzle which moves on the wafer and the wafer in the 3rd Embodiment of this invention. It is explanatory drawing which shows a mode that the wafer after image development is wash | cleaned in the 4th Embodiment of this invention. It is a block diagram of the standby area | region of a nozzle. It is a block diagram which shows the structure of the nozzle and its standby area | region in the board | substrate cleaning apparatus which enforces the board | substrate cleaning method of the 5th Embodiment of this invention. It is explanatory drawing which shows a mode that the wafer after image development is wash | cleaned in the said 5th Embodiment. It is a block diagram which shows the structure of the nozzle in the board | substrate cleaning apparatus which enforces the board | substrate cleaning method of the 6th Embodiment of this invention. It is explanatory drawing which shows a mode that the wafer after image development is wash | cleaned in the said 6th Embodiment. It is a top view which shows an example of the application | coating and developing apparatus incorporating the said developing device. It is a perspective view which shows an example of the application | coating and developing apparatus incorporating the said developing device. It is the graph which showed the result of the evaluation test. It is explanatory drawing explaining the contact angle of the water in the surface of a board | substrate. It is explanatory drawing which shows typically the mode of the cleaning of the wafer surface by the conventional cleaning method. It is explanatory drawing which shows typically the mode of the cleaning of the wafer surface by the conventional cleaning method.

W Wafer 2 Spin chuck 23 Developer nozzle 28 Guide rail 3 Cup body 4 Cleaning liquid nozzle 42 Cleaning liquid supply path 43 Cleaning liquid supply system 44 Nozzle arm 45 Moving substrate 5 Gas nozzle 6 Drying area 7 Controller C Wafer center R Cleaning liquid G N2 gas

Claims (15)

A substrate cleaning method for cleaning and drying a substrate whose surface is water repellent ,
Rotating around an axis perpendicular to the substrate while holding the substrate substantially horizontal;
Supplying the cleaning liquid to the central portion on the rotating substrate using a cleaning liquid nozzle for discharging the cleaning liquid;
Moving the cleaning liquid nozzle so that a position on the substrate that receives the cleaning liquid discharged from the cleaning liquid nozzle moves from the central part on the rotating substrate toward a peripheral part on the substrate by a certain distance;
By discharging a gas to the central portion on the rotating substrate for a predetermined time using a gas nozzle that discharges the gas while maintaining a state where the position on the substrate that receives the cleaning liquid is separated from the central portion on the substrate by a certain distance. Forming a dry region in the center of the substrate;
After the drying region is formed in the center on the substrate, the cleaning liquid nozzle is moved so that the position on the substrate that receives the cleaning liquid continuously moves toward the peripheral edge on the rotating substrate, and The gas nozzle is continuously moved so that the position on the substrate that receives the gas discharged from the gas nozzle follows the moving path of the position on the substrate that receives the cleaning liquid while being spaced apart from the position on the substrate that receives the cleaning liquid by the predetermined distance. A process of
With
The step of moving the cleaning liquid nozzle and continuously moving the gas nozzle includes:
A substrate cleaning method, wherein the cleaning liquid nozzle and the gas nozzle are moved at a speed that is smaller than a speed at which the dry region formed on the substrate spreads the substrate. The process of rotating the substrate
The substrate rotates at the first rotational speed in a state where the position on the substrate that receives the cleaning liquid is located at the center portion on the substrate, substrate cleaning method according to claim 1, comprising the step of changing the rotational speed of the substrate stepwise or continuously so that the substrate is rotating at the first lower than the rotational speed second rotational speed.   The substrate cleaning method according to claim 1, wherein the predetermined distance is 9 mm or more and 15 mm or less. The step of moving the gas nozzle together with the cleaning liquid nozzle is performed such that the position on the substrate that receives the cleaning liquid moves to a position 2 mm to 10 mm away from the peripheral edge of the substrate,
Stopping the discharge of the cleaning liquid while rotating the substrate when the position on the substrate for receiving the cleaning liquid moves to a position away from the peripheral edge of the substrate;
A step of continuously rotating the substrate in order to remove the cleaning solution on the substrate from the substrate by centrifugal force after stopping the discharge of the cleaning solution;
The substrate cleaning method according to claim 1, further comprising:   The step of moving the cleaning liquid nozzle so that the position on the substrate that receives the cleaning liquid moves from the central portion on the substrate toward the peripheral portion on the substrate by a certain distance is performed while rotating the substrate at 1500 rpm to 2000 rpm. The substrate cleaning method according to any one of claims 1 to 4.   The substrate cleaning method according to claim 1, wherein the predetermined time for discharging the gas to form the dry region is 0.5 seconds. A substrate cleaning apparatus for cleaning and drying a substrate whose surface is water repellent ,
Substrate holding means for holding the substrate substantially horizontally;
A rotation driving means for rotating the substrate held by the substrate holding means around an axis perpendicular to the substrate;
A cleaning liquid nozzle for discharging the cleaning liquid onto the rotating substrate;
A cleaning liquid nozzle drive mechanism for moving the cleaning liquid nozzle;
A gas nozzle that discharges gas onto a rotating substrate;
A gas nozzle drive mechanism for moving the gas nozzle;
Control means for controlling the substrate holding means, the rotation driving means, the cleaning liquid nozzle driving mechanism, and the gas nozzle driving mechanism,
The control unit rotates the substrate around the axis perpendicular to the substrate while holding the substrate substantially horizontally by the rotation driving unit, and discharges the cleaning solution from the cleaning solution nozzle to the central portion on the rotating substrate. The center on the substrate is discharged by discharging the gas from the gas nozzle to the central portion on the rotating substrate for a predetermined time while maintaining the position on the substrate that receives the discharged cleaning liquid at a certain distance from the central portion on the substrate. After the dry region is formed in the central portion and the dry region is formed in the central portion on the substrate, the cleaning liquid is moved so that the position on the substrate that receives the cleaning liquid continuously moves toward the peripheral portion on the rotating substrate. The cleaning liquid nozzle is moved by a nozzle drive mechanism, and the position on the substrate that receives the gas discharged from the gas nozzle is fixed from the position on the substrate that receives the cleaning liquid. By the gas nozzle drive mechanism to follow a movement path of the position on the substrate for receiving the washing liquid away spaced while moving the gas nozzle continuously,
The moving speed of the cleaning liquid nozzle and the gas nozzle that are moved together in a state where the position on the substrate that receives the gas and the position on the substrate that receives the cleaning liquid are separated from each other by a certain distance is lower than the speed at which the drying region spreads the substrate. The substrate cleaning apparatus is controlled by the control means so as to have a speed.   The control means is configured such that the substrate rotates at a first rotational speed in a state where the position on the substrate that receives the cleaning liquid is located at a central portion on the substrate, and the position on the substrate that receives the cleaning liquid is the peripheral side on the substrate. The rotational speed of the substrate is changed stepwise or continuously by the rotation driving means so that the substrate rotates at a second rotational speed lower than the first rotational speed in a state where the substrate is positioned at the position. 8. The substrate cleaning apparatus according to 7.   9. The substrate cleaning apparatus according to claim 7, wherein the certain distance is 9 mm or more and 15 mm or less.   The control means discharges the cleaning liquid when a position on the substrate that receives the cleaning liquid that moves together with the gas nozzle toward the peripheral edge of the rotating substrate is located 2 mm to 10 mm away from the peripheral edge of the substrate. 10. The substrate cleaning according to claim 7, wherein the substrate cleaning is stopped and the substrate is continuously rotated in order to remove the cleaning solution on the substrate from the substrate by centrifugal force after the discharge of the cleaning solution is stopped. apparatus.   The control means discharges the cleaning liquid from the cleaning liquid nozzle to the central portion on the rotating substrate, and then places the position on the substrate that receives the cleaning liquid discharged from the cleaning liquid nozzle at a certain distance from the central portion on the substrate. The substrate cleaning apparatus according to claim 7, wherein the substrate is rotated at 1500 rpm to 2000 rpm while the cleaning liquid nozzle is moved.   12. The substrate cleaning apparatus according to claim 7, wherein the predetermined time for supplying the gas to the central portion on the substrate to form the dry region is 0.5 seconds. . A developing method in which a resist film is formed and a developer is supplied to the exposed substrate to form a pattern on the resist film,
A developer supply step of supplying the developer to the substrate;
Next, a cleaning liquid supply step for supplying a cleaning liquid to the substrate;
With
The developing method according to claim 1, wherein the cleaning liquid supply step is performed using the substrate cleaning method according to claim 1. A developing device for forming a pattern on the resist film by supplying a developer to the exposed substrate on which a resist film has been formed,
A developer supply unit for supplying the developer to the substrate;
A cleaning liquid supply unit for supplying a cleaning liquid to the substrate supplied with the developer and cleaning the substrate,
The developing device, wherein the cleaning liquid supply unit includes the substrate cleaning device according to claim 7. A storage medium used for an apparatus for cleaning the surface of a substrate and storing a program operating on a computer,
14. A storage medium, wherein the program includes a group of steps so as to execute the substrate cleaning method according to claim 1 or the developing method according to claim 13.

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