JP7024307B2 - Coating film removing device, coating film removing method and storage medium - Google Patents

Description

The present invention relates to a coating film removing device for removing a peripheral portion of a coating film formed on the surface of a circular substrate with a removing liquid, a coating film removing method, and a storage medium.

One of the processes performed in the photolithography process of forming a coating film pattern on a semiconductor wafer (hereinafter referred to as a wafer) which is a substrate is to supply a solvent to a wafer having a coating film formed on its surface to supply a coating film. There is an edge bead removal (EBR) treatment that removes an unnecessary film on the peripheral edge in a ring shape. In this EBR treatment, the solvent of the coating film is locally discharged from the solvent nozzle to the peripheral edge of the wafer that is placed on the spin chuck and rotates.

In the above EBR treatment, when removing the film on the peripheral edge of the coating film, in order to secure the formation region of the circuit pattern and improve the yield of the semiconductor device, the end portion of the coating film near the boundary with the removal region of the film. It is required to suppress the occurrence of hump. As the number of photolithography processes increases with the miniaturization of circuits, it is expected that the requirements for defects in EBR processing will become stricter, so the development of technology to suppress the occurrence of humps is expected.

In Patent Document 1, the solvent is discharged from the solvent nozzle to dissolve the thin film on the edge of the substrate, and the gas is discharged from the gas nozzle to the portion after the solvent is discharged, so that the solvent is outward from the edge of the substrate. The technique of blowing off and removing it is described in. In this example, the gas is discharged from the diagonally upper rear side with respect to the solvent by the gas nozzle. Therefore, when this method is applied to the EBR treatment, the solvent of the coating film is scattered and the coating film other than the peripheral portion of the wafer is also removed. As a result, there is a concern that the shape of the edge of the coating film may deteriorate.

Further, in Patent Document 2, when the treatment liquid is supplied from the treatment liquid supply unit to the peripheral edge portion of the substrate, a gas ejection portion is provided inside the peripheral edge portion of the substrate rather than the treatment liquid supply portion to prevent the substrate from warping. The technique to correct is described. When this method is applied to the EBR treatment, the gas is ejected from a position closer to the outer edge of the wafer than the solvent of the coating film, so that improvement in the shape of the coating film end portion near the solvent supply region cannot be expected.

Japanese Unexamined Patent Publication No. 6-196401 (Fig. 3, etc.) Japanese Unexamined Patent Publication No. 2012-99833 (paragraph 0031, etc.)

The present invention has been made in view of such circumstances, and an object thereof is to remove a peripheral portion of a coating film formed on the surface of a circular substrate with a removing liquid, and a boundary with a removing region of the coating film. It is an object of the present invention to provide a technique capable of suppressing the occurrence of swelling at the edge of a coating film in the vicinity.

The coating film removing device of the present invention is a coating film removing device for removing the peripheral edge of a coating film formed by supplying a coating liquid to the surface of a circular substrate with the removing liquid.
A rotation holding part that holds and rotates the board,
A removal liquid nozzle that discharges the removal liquid so that the removal liquid is directed to the downstream side in the rotation direction of the substrate is provided on the peripheral edge of the surface of the substrate held by the rotation holding portion.
It is equipped with a control unit that outputs a control signal so that the substrate rotates at a rotation speed of 2300 rpm or more when the removal liquid is discharged .
The control unit
With the substrate rotated at the first rotation speed of 2300 rpm or more, the coating film is cut so that the supply position of the removal liquid is closer to the center of the substrate than the peripheral edge position of the surface of the substrate. The first step of discharging the removal liquid from the removal liquid nozzle while moving it to the position,
It is characterized in that a control signal for executing the second step of moving away from the cut position toward the peripheral edge side of the substrate within 1 second after the supply position reaches the cut position is output .

Further, the coating film removing method of the present invention is a coating film removing method in which the peripheral edge portion of the coating film formed by supplying the coating liquid to the surface of a circular substrate is removed by the removing liquid.
The process of holding the board horizontally in the holding part,
Next, in a state where the substrate is rotated at a rotation speed of 2300 rpm or more, the removal liquid is discharged from the removal liquid nozzle to the peripheral edge of the surface of the substrate so as to be toward the downstream side in the rotation direction of the substrate. Including
In the removal liquid discharge step, the supply position of the removal liquid nozzle is set from the peripheral edge position on the surface of the substrate to the center of the substrate rather than the peripheral edge position in a state where the substrate is rotated at the first rotation speed of 2300 rpm or more. The first step of discharging the removal liquid from the removal liquid nozzle while moving it to the cut position of the coating film closer to the portion, and the substrate from the cut position within 1 second after the supply position reaches the cut position. It is characterized by including a second step of moving away from the peripheral side of the.

Further, the storage medium of the present invention is a storage medium that stores a computer program used in the coating film removing device.
The program is characterized in that steps are set up to carry out the coating film removing method of the present invention.

According to the present invention, when the peripheral portion of the coating film on the substrate surface is removed by the removing liquid, the removing liquid is discharged from the removing liquid nozzle to the peripheral portion of the substrate surface, and the substrate is discharged at 2300 rpm or more when the removing liquid is discharged. It is rotating at the number of rotations of. By rotating the substrate at a large rotation speed of 2300 rpm or more, a large centrifugal force acts on the liquid flow of the removing liquid on the surface of the substrate, and the removing liquid is pressed to the outside of the substrate. As a result, the removal liquid is suppressed from penetrating into the end portion of the coating film, and the occurrence of swelling at the end portion of the coating film is suppressed.

It is a vertical sectional side view which shows one Embodiment of the coating apparatus to which the coating film removing apparatus was applied. It is a top view which shows the coating apparatus. It is a top view which shows the removal liquid nozzle provided in the coating apparatus. It is a vertical sectional side view which shows the removal liquid nozzle. It is a vertical sectional side view which shows the operation of a coating device. It is a vertical sectional side view which shows the operation of a coating device. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a vertical sectional side view of a wafer. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test. It is a top view of the wafer and the removal liquid nozzle. It is a characteristic diagram which shows the result of the evaluation test. It is a characteristic diagram which shows the result of the evaluation test.

An embodiment of the coating device 1 to which the coating film removing device of the present invention is applied will be described with reference to the vertical sectional side view of FIG. 1 and the plan view of FIG. The coating device 1 is configured to be capable of performing a treatment of applying a coating liquid to a wafer W, which is a substrate, to form a coating film, and an EBR treatment. The wafer W is circular and has a diameter of, for example, 300 mm. Further, a notch N is formed on the peripheral edge portion of the wafer W as a notch indicating the direction of the wafer W.

In the figure, 11 is a spin chuck forming a rotation holding portion for holding and rotating the wafer W. The spin chuck 11 attracts the central portion of the back surface of the wafer W to hold the wafer W horizontally, and is configured to be rotatable clockwise along a vertical axis by a rotation mechanism 21. The spin chuck 11 and the rotation mechanism 21 are connected by a shaft 211, and a cup 22 is provided around the wafer W held by the spin chuck 11. The cup 22 is exhausted through the exhaust pipe 23, and the liquid spilled from the wafer W into the cup 22 is removed by the drain pipe 24.

The exhaust pipe 23 is connected to, for example, an exhaust mechanism 232, which is an exhaust passage in a factory, via, for example, an exhaust amount adjusting unit 231 made of a damper, and is configured so that the pressure in the cup 22 can be adjusted. Reference numeral 25 in the figure is an elevating pin, which is configured to transfer the wafer W between the transfer mechanism of the wafer W (not shown) and the spin chuck 11 by elevating and descending by the elevating mechanism 26.

The coating device 1 includes a coating liquid nozzle 41 that discharges the coating liquid vertically downward, and a solvent nozzle 42 that discharges the solvent that is the solvent of the coating liquid vertically downward. The coating liquid nozzle 41 is connected to a coating liquid supply mechanism 44 that supplies the coating liquid to the nozzle 41 via a flow path 43 provided with an on-off valve V1. Further, the solvent nozzle 42 is a nozzle used for pretreatment performed before discharging the coating liquid to the wafer W, and supplies a solvent to supply the solvent to the nozzle 42 via a flow path 45 provided with an on-off valve V2. It is connected to the mechanism 46. As shown in FIG. 2, the coating liquid nozzle 41 and the solvent nozzle 42 are supported by an arm 48 configured to move up and down and horizontally by a moving mechanism 47, and are supported on the center portion of the wafer W and the outside of the cup 22. It is configured to be movable with and from the retracted position of. Reference numeral 49 in the figure is a guide for the moving mechanism 47 to move in the horizontal direction as described above.

Further, the coating device 1 includes a removing liquid nozzle 3 used for performing the above-mentioned EBR treatment. The removing liquid nozzle 3 discharges the removing liquid onto the peripheral edge of the surface of the wafer W held by the spin chuck 11 so that the removing liquid is directed to the downstream side in the rotational direction of the wafer W. The removal liquid nozzle 3 is formed in a straight tube, for example, and its tip is opened as a removal liquid discharge port 30.

The removing liquid in this example is a solvent that is a solvent for the coating liquid, and the removing liquid nozzle 3 is connected to the solvent supply mechanism 46 via a flow path 31 provided with an on-off valve V3, and is connected to the solvent nozzle 42 and the removing liquid. The nozzle 3 is configured to supply the solvent (removing liquid) independently of each other from the common solvent supply mechanism 46. Further, the removing liquid nozzle 3 is supported by an arm 33 configured to be movable up and down and horizontally by a moving mechanism 32 as shown in FIG. 2, and has a processing position for discharging the removing liquid to the peripheral portion of the wafer. It is configured to be movable with and from the retracted position on the outside of the cup 22. In FIG. 2, the moving direction of the removing liquid nozzle 3 is shown as the Y direction, and the horizontal direction orthogonal to the Y direction is shown as the X direction. Reference numeral 34 in the figure is a guide for the moving mechanism 32 to move in the horizontal direction as described above.

As shown in FIG. 3, the removing liquid nozzle 3 forms a straight line connecting the discharge port 30 of the removing liquid nozzle 3 and the supply position P and the tangent line of the wafer W at the supply position P when viewed in a plane. The angle θ is set to, for example, 0 degrees. This angle θ is preferably small from the viewpoint of suppressing liquid splashing. That is, it is preferable that the tangent line L at the supply position P and the discharge direction of the removal liquid are aligned, but it is even more preferable if the temperature is within 6 degrees. The removal liquid supply position P is a landing position when the removal liquid discharged from the removal liquid nozzle 3 reaches the wafer surface. In FIG. 3, a part of the outer edge Lw of the wafer W is shown by a solid line, the tangent line L of the wafer W at the supply position P, and the discharge direction of the removing liquid are shown by dotted lines.

Further, as shown in FIG. 4, the removal liquid nozzle 3 has an angle Z formed by the straight line connecting the removal liquid nozzle 3 and the supply position P and the surface of the wafer W, for example, 10 degrees when viewed in a vertical plane. It is set. The angle Z is preferably small from the viewpoint of suppressing liquid splashing. Therefore, it is preferably 20 degrees or less, but more preferably 15 degrees or less. Further, the diameter A of the discharge port 30 of the removal liquid nozzle 3 is set to, for example, 0.15 mm to 0.35 mm, and preferably 0.15 mm to 0.25 mm.

Further, the coating device 1 includes a control unit 7. The control unit 7 is composed of, for example, a computer, and has a program storage unit (not shown). In this program storage unit, a program in which instructions (step groups) are set so that the coating film forming process and the EBR process described later can be performed is stored. Then, by outputting a control signal from the control unit 7 to each part of the coating device 1 by this program, the operation of each part of the coating device 1 is controlled. Specifically, opening / closing control of the opening / closing valves V1 to V3, movement of the removing liquid nozzle 3 by the moving mechanisms 32 and 47, movement of the coating liquid nozzle 41 and the solvent nozzle 42, rotation of the spin chuck 11 by the rotating mechanism 21, and exhaust volume adjusting mechanism 231. Each operation such as adjustment of the pressure in the cup 22 and the raising / lowering of the raising / lowering pin 25 by the raising / lowering mechanism 26 is controlled. This program is stored in the program storage unit in a state of being stored in a storage medium such as a hard disk, a compact disk, a magnet optical disk, or a memory card.

Further, the control unit 7 of this example is configured to output a control signal for executing the first step and the second step in the EBR processing. The first step is that the wafer W is rotated at a first rotation speed of 2300 rpm or more, and the removal liquid supply position P is set from the peripheral edge position on the surface of the wafer W to the wafer W from the peripheral edge position. This is a step of ejecting the removal liquid from the removal liquid nozzle 3 while moving the coating film to a cut position closer to the center portion. A bevel portion W1 is provided on the peripheral edge of the wafer W. In this example, the peripheral edge position is a flat portion on the inner side of the bevel portion W1 and the edge of the flat surface portion. It is a position closer to the inward side by 0.1 mm to 0.3 mm from (the boundary with the bevel part). The second step is a step in which the removing liquid nozzle 3 separates from the cutting position to the peripheral edge side of the wafer W within 1 second, preferably within 0.5 seconds, after the supply position P reaches the cutting position.

Further, after the second step, the control unit 7 sets the supply position P between the cut position and the peripheral edge position, or at the peripheral edge position, and the wafer has a second rotation speed lower than the first rotation speed. It is configured to output a control signal for executing the step of discharging the removal liquid from the removal liquid nozzle 3 while rotating W. In the second position, the second rotation speed is set to, for example, 500 to 2000 rpm.

Subsequently, the coating film forming process (coating film forming step) and the EBR process (EBR step) performed by the coating device 1 will be described. First, the wafer W is transported and placed on the spin chuck 11 by a transport mechanism (not shown). Then, the inside of the cup 22 is exhausted with an exhaust pressure of, for example, 65 Pa, and then the solvent is discharged from the solvent nozzle 42 onto the center of the wafer W, while the rotation of the wafer W is started and the solvent is discharged from the wafer W by centrifugal force. It is applied to the entire surface of the wafer W to improve the wettability of the surface of the wafer W with respect to the coating liquid. Then, in a state where the wafer W is rotated, the coating liquid is discharged from the coating liquid nozzle 41 onto the center of the wafer W, and in this example, the resist liquid is discharged, and the coating liquid is applied to the entire surface of the wafer W by centrifugal force. After that, the wafer W is rotated for a predetermined time to dry the liquid film, and the coating film 10 is formed.

Then, the EBR step is executed. In this process, for example, the amount of exhaust air in the cup 22 is made larger than the step of forming the coating film, and the exhaust pressure is set to 50 Pa or more, for example, 75 Pa. Then, as shown in FIG. 5A, the removing liquid nozzle 3 is moved from the retracted position on the outside of the wafer so that the supply position of the removing liquid becomes the peripheral position, and the first step is executed. Then, while the wafer W is rotated at the first rotation speed of 2300 rpm or more, the removal liquid supply position P is moved from the peripheral edge position to the first position which is the cutting position, and is removed from the removal liquid nozzle 3. The liquid is discharged at a flow rate of, for example, 20 ml / min to 60 ml / min, preferably 55 ml / min or more (FIG. 5 (b)). The first position (cut position) in this example is, for example, a position 2 mm closer to the center portion side of the wafer W from the outer edge of the wafer W. It should be noted that in the drawings, the dimensional ratios are not always accurate in order to prioritize the understanding of the technology.

In the first step, it is necessary to rotate the wafer W at a rotation speed of 2300 rpm or more in order to prevent the occurrence of hump at the end of the coating film, but 2500 rpm or more is more preferable and 3000 rpm. The above is more preferable. For example, it is very preferable to set it to 4000 rpm. The upper limit of the rotation speed of the wafer W in the first step is, for example, 5000 rpm.

Then, the second step is executed. That is, immediately after the removal liquid supply position P reaches the cut position, the removal liquid nozzle 3 is moved from the first position to the peripheral edge side of the wafer W immediately, for example, without having a waiting time. Without having a waiting time, for example, even if the waiting time is not included in the moving recipe of the removing liquid nozzle 3, the removing liquid nozzle 3 is placed at the cut position at the cut position, for example, about 0.1 to 0.5 seconds due to the operation of the drive mechanism. In this example, it refers to a state of stopping for 0.1 seconds. Immediately after the removal liquid supply position reaches the first position, it is necessary to move the removal liquid nozzle 3 to the peripheral edge side, which is, for example, within 1 second. Therefore, for example, this step is a step in which the removal liquid nozzle 3 leaves the peripheral side of the wafer W without substantially stopping after the removal liquid supply position P reaches the cut position.

The removing liquid is discharged from the removing liquid nozzle 3 so as to be toward the downstream side in the rotation direction of the wafer W and so that the extension line of the discharging locus of the removing liquid is directed to the outside of the peripheral edge portion of the coating film. Further, since the wafer W rotates at a high rotation speed of 2300 rpm or more, a large centrifugal force is generated, and the liquid flow of the removing liquid quickly flows so as to be pushed out toward the outer side of the wafer W. As a result, in the removal liquid supply region, the coating film 10 is softened and dissolved by the removal liquid, and the removal liquid containing the dissolved components of the coating film is pushed out toward the outside of the wafer W by a large centrifugal force. Will be removed.

In this way, after executing the second step, the step of cleaning the bevel portion W1 on the end surface of the wafer is executed. In this step, the supply position P of the removing liquid is set between the first position and the peripheral edge position, or at the peripheral edge position, and the wafer W is removed while rotating the wafer W at a second rotation speed of 500 rpm to 2000 rpm, for example, 1000 rpm. This is a step of discharging the removing liquid from the liquid nozzle 3 (FIG. 5 (c)). The supply position (second position) of the removing liquid in this step is, for example, a position 0.5 mm closer to the inside of the wafer W from the outer edge of the wafer W, as shown in FIG. 5 (c), and in this step, the removal liquid is supplied. The removal liquid is continuously supplied to this second position for, for example, 1 second or longer, and in this example, 5 seconds.

The second rotation speed when the removal liquid is discharged to the second position is lower than the first rotation speed when the removal liquid is discharged to the first position. Therefore, the liquid flow of the removing liquid is pushed out toward the outside of the wafer W by centrifugal force at a slower speed than when it is discharged to the first position, and the removing liquid discharged to the wafer W. While suppressing the liquid splashing phenomenon that is repelled from the rotating wafer W, the wafer flows so as to wrap around from the outer edge of the wafer W to the back surface side. In this way, in the bevel portion W1 on the end surface of the wafer W, the removing liquid spreads to the back surface side as well, and the components adhering to the bevel portion W1 are washed by the removing liquid.

In this way, after removing the unnecessary peripheral portion of the coating film and cleaning the bevel portion W1, for example, the displacement is returned to the displacement at the time of forming the coating film, and the removal liquid from the removal liquid nozzle 3 is removed. Discharge is stopped and moved to the standby position (FIG. 5 (d)). Then, the rotation of the wafer W is stopped, and the wafer W is carried out from the coating device 1 by a transfer mechanism (not shown).

According to the above-described embodiment, when the removing liquid is supplied to the peripheral edge portion of the coating film on the wafer surface to remove the unnecessary coating film on the peripheral edge portion, the wafer W is rotated at 2300 rpm or more when the removing liquid is discharged. It is rotated at the number of rotations. Therefore, a large centrifugal force is generated, and the liquid flow of the removing liquid flows so as to be pushed out toward the outer side of the wafer W. As a result, the removing liquid at the cut position is suppressed from penetrating into the coating film end portion, and the generation of a force for lifting the coating film edge portion is suppressed. In this way, the unnecessary peripheral edge portion of the coating film is removed in a state where the occurrence of hump at the end portion of the coating film is suppressed. Further, as is clear from the evaluation test described later, the height of the hump by the EBR treatment is reduced regardless of the type of the removing liquid.

Further, since the removal liquid supply position P is immediately moved from the cut position to the peripheral side within, for example, within 1 second after reaching the cut position, the removal liquid supplied to the cut position is affected by a large centrifugal force. It quickly flows from the cut position toward the peripheral edge side of the wafer W. Therefore, it is suppressed that the removing liquid at the cut position permeates the end portion of the coating film, and the formation of the hump is further suppressed. Further, by moving the removal liquid supply position P from the cut position to the peripheral side within 1 second after reaching the cut position, the time required for the EBR processing is shortened, which contributes to the improvement of the throughput.

Furthermore, if the rotation speed of the wafer W during the EBR step is high, cleaning of the bevel portion W1 may be insufficient, but cleaning that discharges the removing liquid at a position outside the cut position of the coating film. By performing the steps, the cleanliness at the bevel portion W1 can be increased. In this washing step, the second rotation speed is lower than the first rotation speed, and the supply time of the removing liquid at the second position is long, but the second position is closer to the peripheral edge of the wafer W than the first position. Therefore, the permeation of the removing liquid into the end of the coating film is suppressed. As described above, in the cleaning step, the magnitude of the second rotation speed, the second position, and the supply position are set so that the bevel portion W1 can be sufficiently cleaned while suppressing the occurrence of hump. The stop time when the position is set to 2 is determined.

On the other hand, when the rotation speed of the wafer W at the time of supplying the removing liquid is increased, a liquid splashing phenomenon occurs, and the mist of the removing liquid scattered by the liquid splashing reattaches to the wafer W and becomes a mist-like defect (wet particles). Therefore, it is recognized that the number of defects in the peripheral portion of the wafer increases. Therefore, in the above-described embodiment, the occurrence of the liquid splash phenomenon is suppressed by optimizing the angle of the removing liquid nozzle 3, and as a result, the number of defects is reduced. That is, in the removing liquid nozzle 3 of the present embodiment, the formed angle θ is set to 6 degrees or less, and the formed angle Z is set to 20 degrees or less. As a result, the removing liquid is discharged from the removing liquid nozzle 3 tilted slightly upward from the horizontal plane with respect to the surface of the wafer W in substantially the rotational direction. Therefore, when the removing liquid is supplied to the high-speed wafer W, the impact force when the removing liquid collides with the surface of the wafer W becomes small, and the removing liquid easily adapts to the wafer W, resulting in liquid splashing. Be prevented. Further, since the liquid splash is prevented, the adhesion of wet particles to the peripheral portion of the wafer is also reduced.

Further, in the EBR step, the wet particles can be improved by setting the inside of the cup 22 to a high exhaust state of, for example, 50 Pa or more. This is because the mist-like removing liquid that has bounced off is quickly discharged from the exhaust passage.

Further, when the rotation speed of the wafer W at the time of supplying the removing liquid is increased, the cutting accuracy of the cut surface of the coating film (the end surface of the coating film at the cut position) is lowered, and the cut surface becomes rough and smooth when viewed in a plane. It is allowed to decrease. Therefore, in the embodiment, the diameter A of the discharge port 30 of the removal liquid nozzle 3 is set to be small, that is, 0.15 mm to 0.35 mm. As a result, the discharge pressure of the removal liquid increases, and the cutting force of the removal liquid at the cutting position of the coating film increases, so that the cutting accuracy of the cut surface is improved. Further, in this example, the discharge flow rate of the removing liquid when the supply position P moves from the peripheral position to the first position (cut position) is set to 20 ml / min to 60 ml / min. As a result, the discharge pressure of the removing liquid is increased, and the cutting accuracy of the cut surface is further improved.

(Second embodiment)
This embodiment differs from the above-described embodiment in that the control unit 7 is configured to output a control signal for repeating the first step and the second step a plurality of times. .. First, as shown in FIG. 6A, the removing liquid nozzle 3 is moved from the retracted position on the outside of the wafer to the peripheral position. Then, with the wafer W rotated at the first rotation rate of 2300 rpm or more, the removal liquid supply position P is moved from the peripheral edge position of the surface of the wafer W to the first position which is the cut position, and is removed. The removing liquid is discharged from the liquid nozzle 3 at a flow rate of, for example, 20 ml / min to 60 ml / min (first step, FIG. 6 (b)). Subsequently, immediately after the removal liquid supply position P reaches the cut position, the removal liquid is immediately moved from the first position to, for example, the peripheral position within 1 second (second step, FIG. 6 (c)). Also in this second step, the removal liquid is discharged from the removal liquid nozzle 3 at a flow rate of 20 ml / min to 60 ml / min in a state where the wafer W is rotated at the first rotation speed of 2300 rpm or more. In this way, the first step and the second step are repeated a plurality of times, for example, five times.

By performing the first step and the second step in this way, as described above, it is possible to remove unnecessary peripheral edges of the coating film while suppressing the occurrence of hump. Further, by repeating the first step and the second step, the cutting force of the removing liquid at the cutting position of the coating film is increased, so that the cutting accuracy of the cut surface is improved as is clear from the evaluation test described later. Be done. Further, by repeating the first step and the second step, the removing liquid can easily wrap around from the end portion of the wafer W to the back surface side, and the bevel portion W1 can be washed. It should be noted that, as in the second embodiment, after repeating the first step and the second step, the cleaning step of the first embodiment may be carried out.

As described above, by rotating the wafer W at a high rotation speed when discharging the removing liquid, it is possible to remove unnecessary peripheral edges of the coating film while suppressing the occurrence of hump, and the height of the hump at this time. As is clear from the evaluation test described later, the higher the rotation speed of the wafer W, the lower the value. On the other hand, when the rotation speed of the wafer W is high, the liquid splashing phenomenon tends to occur, defects occur, and the smoothness of the cut surface tends to decrease. For this reason, the present inventors rotate the wafer W at a rotation speed of 2300 rpm or more when discharging the removing liquid, thereby suppressing the occurrence of hump as compared with the conventional case, and eliminating the need for a coating film. It is considered that the peripheral part can be removed.

Subsequently, the evaluation test of the present invention will be described with reference to FIGS. 7 to 19.
(Evaluation test 1: Hump height evaluation)
The wafer W was rotated at 1000 rpm, 2000 rpm, 3000 rpm, and 4000 rpm, and the coating film forming step and the EBR step were performed, and the height of the hump at the end of the coating film after the treatment was evaluated. When the coating film is chemical solution A which is an SOC (Spin On Carbon) material, the removal solution is OK-73 thinner, the cut position is 2.5 mm inside from the outer edge of the wafer, and the stop time of the supply position at the cut position is 5 seconds. And, when the stop time was 0 seconds, the height of the hump at each rotation speed was measured. The hump height was determined using a step measuring device, the height from the coating film was taken as the hump height, and the hump height was similarly evaluated for a plurality of wafers W.

The result is shown in FIG. In the figure, the vertical axis is the hump height (nm), and the horizontal axis shows the stop time and the rotation speed of the removal liquid supply position at the cut position. The average value of the hump height when the stop time was 5 seconds was 724.92 nm at a rotation speed of 1000 rpm, 481.31 nm at 2000 rpm, 302.48 nm at 3000 rpm, and 256.49 nm at 4000 rpm. The average value of the hump height when the stop time was 0 seconds was 512.99 nm at a rotation speed of 1000 rpm, 312.97 nm at 2000 rpm, 240.76 nm at 3000 rpm, and 209.35 nm at 4000 rpm.

As described above, it was found that the higher the rotation speed, the lower the hump height in both the stop time of 5 seconds and 0 seconds. It was also confirmed that when the rotation speeds are the same, unnecessary films can be removed and the hump height is lowered even if the stop time is 0 seconds. As a result, when the rotation speed is high, the force for pushing the removal liquid supplied to the cut position by a large centrifugal force toward the outer edge of the wafer W increases, and the cutting force at the cut position increases, so that the stop time is 0 seconds. Even so, it is understood that unnecessary films can be sufficiently removed.

Further, the coating film was changed to the resist chemical solution B, the SOC material chemical solution C, the resist chemical solution D, the SiARC material chemical solution E, and the removal solution to OK-73 thinner and cyclohexanone, respectively, and the same evaluation was performed. As a result, as in the evaluation test 1, it was confirmed that the higher the rotation speed, the lower the hump height, and when the rotation speed is the same, the hump height is lower when the stop time is 0 seconds. Was done. Therefore, it is understood that the method of the present invention can reduce the hump height without depending on the type of the coating film or the removing liquid.

In this way, the higher the rotation speed of the wafer W, the lower the hump height. However, from the transition of the hump height, the change in the hump height becomes smaller when the hump height exceeds 3000 rpm. Therefore, at a rotation speed of 2300 rpm or more. If there is, it is considered that it can sufficiently contribute to the reduction of the hump height. Regarding the stop time at the supply position, the average value of the hump height is lower when the stop time is 5 seconds and the rotation speed is 3000 rpm than when the stop time is 0 seconds and the rotation speed is 2000 rpm. It is considered that the hump height can be reduced within 1 second.

(Evaluation test 2: Liquid splash evaluation)
The coating film formation step and the EBR step were performed, and the presence or absence of liquid splash was evaluated by taking a moving image of the processing state. At this time, the removing liquid nozzle 3 has the forming angle θ of 0 degrees and 8.5 degrees, the forming angle Z of 10 degrees, 20 degrees and 30 degrees, and the discharge flow rate of the removing liquid of 13 ml / min and 20 ml / min. The same evaluation was performed at 30 ml / min, respectively, and in each case, the maximum rotation speed at which liquid splash did not occur was determined. The coating film was chemical solution A, the removal solution was OK-73 thinner, the cut position was 2.5 mm inside from the outer edge of the wafer, and the stop time of the supply position at the cut position was 10 seconds.

The result is shown in FIG. In the figure, the horizontal axis is the maximum rotation speed (rpm) at which liquid splash does not occur, and the vertical axis shows the angle (angle θ, Z) of the removal liquid nozzle 3 and the discharge flow rate (ml / min). As a result, when comparing the angle θ formed by the tangent line of the removing liquid nozzle 3, the maximum rotation speed is larger at 0 degrees, and when comparing the angles Z formed with the wafer surface, those at 10 degrees and 20 degrees. It was found that the maximum number of revolutions was larger than 30 degrees. From this, it is understood that the liquid splash can be reduced by adjusting the formed angle θ and the formed angle Z. Further, it was found that the maximum rotation speed changes depending on the discharge flow rate even if the angle θ formed by the removing liquid nozzle 3 and the angle Z formed are the same. Further, a coating film is formed on the wafer W having irregularities of ± 300 μm, and the removal liquid nozzle 3 having an angle θ formed by 8.5 degrees and an angle Z formed by 30 degrees is formed, and the angle θ formed is 0 degrees and the angle Z formed is formed. When EBR processing was performed using the removal liquid nozzle 3 having a 10 degree angle, it was confirmed that the cutting accuracy was improved in the removal liquid nozzle 3 having an angle θ formed by 0 degree and an angle Z formed by 10 degrees. ..

As a result of the above, it was confirmed that when the forming angle θ is 8.5 degrees and the forming angle Z is 20 degrees or less, the maximum rotation speed exceeds 2300 rpm. From this, if the forming angle θ is within 6 degrees, the liquid splash can be reduced even if the maximum rotation speed is 2300 rpm or more by adjusting the discharge flow rate and the forming angle Z, and the forming angle Z is within 20 degrees. If there is, it is considered that the liquid splash can be reduced even if the maximum rotation speed is 2300 rpm or more by adjusting the discharge flow rate and the angle θ.

(Evaluation test 3: Defect evaluation)
After the step of forming the coating film, the wafer W is rotated at 4000 rpm, and the EBR step is performed by reciprocating once between the peripheral edge position and the cut position of the wafer W while discharging the removal liquid from the removal liquid nozzle 3. The number of defects (wet particles) was evaluated by extracting mist-like defects using an SEM (scanning electron microscope).

At this time, the removal angle θ is 0 degrees, the angle Z is 10 degrees, the diameter A of the discharge port 30 is 0.2 mm, the removal angle θ is 8.5 degrees, and the angle Z is 30 degrees. A removing liquid nozzle 3 having a diameter A of the discharge port 30 of 0.3 mm was used. Chemical solution A was used as the coating film, OK-73 thinner was used as the removing solution, the exhaust pressure in the coating film forming step was 65 Pa, and the exhaust pressure in the cup 22 in the EBR step was 75 Pa. Further, the stop time of the supply position at the cut position was set to 0 seconds, and the evaluation was performed by changing the cut position (cut width).

Under each condition, the same evaluation was performed on each of the three wafers W, and the results are shown in FIG. In the figure, the horizontal axis shows the cut width and the conditions of the removing liquid nozzle 3, and the vertical axis shows the number of mist-like defects (pieces) having a size of 50 nm or more. As a result, it was confirmed that the number of mist-like defects was significantly reduced by using the removing liquid nozzle 3 having a forming angle θ of 0 degrees and a forming angle Z of 10 degrees. Since it has been confirmed in the evaluation test 2 that the liquid splash is reduced by optimizing the angle θ formed by the removal liquid nozzle 3, the mist-like defect is reduced by suppressing the liquid splash. It is presumed that it was.

(Evaluation test 4-1: Exhaust pressure evaluation)
After the coating film forming step, the wafer W is rotated at 4000 rpm, and the EBR step is performed by reciprocating 60 times between the peripheral edge position and the cut position of the wafer W while discharging the removal liquid from the removal liquid nozzle 3. The number of the above was evaluated using SEM. At this time, a removing liquid nozzle 3 having an forming angle θ of 0 degrees, an forming angle Z of 10 degrees, and a discharge port 30 having a diameter A of 0.2 mm was used. The coating film is a resist chemical solution B, the removal solution is OK-73 thinner, the stop time of the supply position at the cut position is 0 seconds, the cut width is 2 mm, the discharge flow rate is 25 ml / min, and the cup 22 during the EBR step. The treatment was performed by changing the exhaust pressure of the above, and the evaluation was performed. The reason why the removing liquid nozzle 3 is moved 60 times is that the number of defects increases as the number of treatments increases, so that the number of defects is increased and the occurrence state of the defects can be grasped more accurately.

Under each condition, the same evaluation was performed on each of the three wafers W, and the results are shown in FIG. In the figure, the horizontal axis shows the exhaust pressure in the cup 22, and the vertical axis shows the number of defects having a size of 50 nm or more. As a result, it was confirmed that the number of defects decreased as the exhaust pressure in the cup 22 increased, and that defects occurred at 50 Pa or less at a rotation speed of 4000 rpm.

(Evaluation test 4-2: Exhaust pressure evaluation)
The rotation speed of the wafer W was changed to 3500 rpm, and the other conditions were the same, and the evaluation was performed in the same manner as in (Evaluation Test 4-1). Under each condition, the same evaluation was performed on each of the three wafers W, and the results are shown in FIG. In the figure, the horizontal axis indicates the exhaust pressure in the cup 22, and the vertical axis indicates the number of defects having a size of 50 nm or more. As a result, it was confirmed that at a rotation speed of 3500 rpm, defects occur at 30 Pa or less.

(Evaluation test 4-3: Exhaust pressure evaluation)
The rotation speed of the wafer W was changed to 3000 rpm, and the other conditions were the same, and the evaluation was performed in the same manner as in (Evaluation Test 4-1). Under each condition, the same evaluation was performed on each of the three wafers W, and the results are shown in FIG. In the figure, the horizontal axis indicates the exhaust pressure in the cup 22, and the vertical axis indicates the number of defects having a size of 50 nm or more. As a result, it was confirmed that a defect occurred at an exhaust pressure of 23 Pa at a rotation speed of 3000 rpm.

(Evaluation test 4-4: Exhaust pressure evaluation)
After the step of forming the coating film, the rotation speed of the wafer W is set to 3000 rpm, 3500 rpm, and 4000 rpm, and the EBR step is performed by moving the wafer W once from the peripheral edge position to the cut position while discharging the removal liquid from the removal liquid nozzle 3. , Other conditions were evaluated in the same manner as in (Evaluation Test 4-1). Under each condition, the same evaluation was performed on each of the three wafers W, and the results are shown in FIG. In the figure, the horizontal axis shows the exhaust pressure in the cup 22, and the vertical axis shows the number of mist-like defects having a size of 50 nm or more. As a result, it was found that defects are likely to occur when the rotation speed of the wafer W is high, but the number of defects can be reduced by increasing the exhaust pressure in the cup 22. Further, when compared at the same exhaust pressure (75 Pa, 90 Pa), it was confirmed that the number of mist-like defects was smaller at the high rotation speed. It is presumed that this is because when the rotation speed is lowered, liquid splashing tends to occur in the notch portion of the wafer W, which causes an increase in the number of mist-like defects.

(Evaluation test 5-1: Bevel site cleaning evaluation)
After the coating film forming step, the wafer W is rotated at 4000 rpm, the EBR step is performed with the stop time at the first position (cut position) set to 0 seconds, and then the supply position is moved to the second position, and the wafer W is moved. Was rotated at 2000 rpm to perform a cleaning step. The stop time at the second position was changed between 1 second and 5 seconds, and the cleanliness of the bevel portion W1 was confirmed using a bevel inspection device. The removal liquid nozzle 3 has an angle θ of 0 degrees, an angle Z of 10 degrees, and a diameter A of the discharge port 30 of 0.2 mm. The coating film is chemical solution B, the removal solution is OK-73 thinner, and cut. The position was 2 mm inside from the outer edge of the wafer, and the second position was 0.5 mm inside from the outer edge of the wafer.

As a result, the cleanliness of the bevel portion W1 is improved by performing the cleaning step after the EBR step, and the cleanliness of the bevel portion W1 is increased by extending the supply time of the removing liquid at the second position. It was recognized that it would be. It was confirmed that if the supply time of the removing liquid at the second position was 3 seconds or more, the contamination of the bevel portion W1 was improved.

(Evaluation test 5-2: Bevel site cleaning evaluation)
The EBR step and the washing step were carried out in the same manner as in (Evaluation test 5-1). The stop time at the second position was set to 5 seconds, the rotation speed of the wafer W (second rotation speed) in the washing step and the exhaust pressure in the cup 22 were changed, and the cleanliness of the bevel portion was confirmed. The coating film was chemical solution B, the removal solution was OK-73 thinner, the cut position was 2 mm inside from the outer edge of the wafer, and the second position was 0.5 mm inside from the outer edge of the wafer. In addition, the same evaluation was performed when the cleaning step was not performed.

Under each condition, the same evaluation was performed on each of the three wafers W, and the results are shown in FIG. In the figure, the horizontal axis is the processing conditions such as exhaust pressure and rotation speed, and the vertical axis is the number of defects with a size of 50 nm or more, and the stop time at the second position and the condition where the second rotation speed is not described. Is the case where the cleaning step is not performed. As a result, under the condition that the exhaust pressure was 90 Pa and the second rotation speed was 1000 rpm, some wafers W had a large number of defects, but the remaining wafers W under the same conditions had a small number of defects, so a cleaning step was carried out. However, it can be said that the number of defects does not deteriorate.

Further, with respect to (evaluation test 5-2), the number of mist-like defects having a size of 50 nm or more was evaluated by a defect review SEM (Defect Review-SEM: Defect Review-Scanning Electron Microscope). The result is shown in FIG. Even in this case, it was confirmed that the number of defects was not deteriorated by carrying out the cleaning step.

(Evaluation test 6-1: Evaluation of cut surface)
After the coating film forming step, the EBR step was performed with the stop time at the cut position set to 0 seconds. At this time, the forming angle θ is 0 degrees, the forming angle Z is 10 degrees, the diameter A of the discharge port 30 is 0.3 mm, the forming angle θ is 8.5 degrees, and the forming angle Z is 30 degrees. A removal liquid nozzle 3 having a diameter A of the discharge port 30 of 0.3 mm was used. The coating film was chemical solution A, the removal solution was OK-73 thinner, the cut width was 2.5 mm, and the EBR step was performed by changing the discharge flow rate and the rotation speed, and evaluation was performed. The smoothness of the cut surface was evaluated by a bevel inspection device.

Under each condition, the same evaluation was performed on each of the three wafers W, and the results are shown in FIG. In the figure, the horizontal axis is the processing conditions such as discharge flow rate and rotation speed, and the vertical axis is the smoothness (mm) of the cut surface. The smaller the value, the less rough the cut surface and the higher the smoothness. ing. As a result, it was found that the smoothness of the cut surface deteriorated when the removing liquid nozzle 3 having a forming angle θ of 0 degrees and a forming angle Z of 10 degrees was used, but the smoothness deteriorated when the rotation speed was increased. However, it was confirmed that it was improved by increasing the discharge flow rate.

(Evaluation test 6-2: Cut surface evaluation)
Using the removal liquid nozzle 3 having an angle θ of 0 degrees and an angle Z of 10 degrees, the diameters A of the discharge port 30 are set to 0.3 mm and 0.2 mm, and other conditions are (evaluation test 6-1). ), The smoothness of the cut surface was evaluated. The result is shown in FIG. In the figure, the horizontal axis is the processing conditions such as the discharge flow rate and the rotation speed, and the vertical axis is the smoothness (mm) of the cut surface. As a result, it was found that the smoothness of the cut surface was improved by reducing the diameter A of the discharge port 30 in the removing liquid nozzle 3 having an angle θ formed by 0 degrees and an angle Z formed by 10 degrees. It was also confirmed that the improvement was achieved by increasing the discharge flow rate.

When the diameter A of the removal liquid nozzle 3 is 0.3 mm, when the discharge flow rate is 27 ml / min, the smoothness at the rotation speeds of 3500 rpm and 4000 rpm is almost the same. Therefore, the discharge port 30 of the removal liquid nozzle 3 The diameter A of the above is considered to be 0.15 mm to 0.35 mm. Further, in the comparison between the diameter A of 0.3 mm and 0.2 mm when the discharge flow rate is 20 ml / min, the smoothness of 0.2 mm is better when the rotation speed is 2900 rpm or more. If the diameter A of the discharge port 30 of 3 is 0.15 mm to 0.25 mm, it can be said that the smoothness of the cut surface is sufficiently improved.

(Evaluation test 6-3: Cut surface evaluation)
After the step of forming the coating film, the wafer W was rotated at 4000 rpm, and the EBR step was performed with the stop time at the cut position set to 0 second. Next, the supply position was moved to the second position, the wafer W was rotated at 2000 rpm with the stop time of the second position set to 5 seconds, and the cleaning step was performed. The smoothness of the cut surface was confirmed by changing the discharge flow rate of the removal liquid in the EBR step and the cleaning step. The coating film was chemical solution A, the removal solution was OK-73 thinner, the diameter A of the discharge port 30 was 0.2 mm, the cut position was 2 mm inside from the outer edge of the wafer, and the second position was 0.5 mm inside from the outer edge of the wafer.

The result is shown in FIG. In the figure, the horizontal axis is the discharge flow rate, the vertical axis is the smoothness (mm) of the cut surface, and Ref uses the removal liquid nozzle 3 having an angle θ formed by 8.5 degrees and an angle Z formed by 30 degrees. The data is obtained when the stop time at the cut position is 5 seconds and the rotation speed of the wafer W is 2000 rpm. As a result, it was found that the smoothness of the cut surface was improved by increasing the discharge flow rate in the removing liquid nozzle 3 having an forming angle θ of 0 degrees and an forming angle Z of 10 degrees. Since the smoothness is significantly improved when the discharge flow rate is 40 ml / min or more, it is considered that the smoothness of the cut surface can be sufficiently improved when the discharge flow rate is 40 ml / min to 70 ml / min.

(Evaluation test 7: Discharge flow rate evaluation)
The hump height of the wafer W treated in the same manner as in (evaluation test 6-3) was confirmed by a step measuring device. The result is shown in FIG. In the figure, the horizontal axis is the discharge flow rate, and the vertical axis is the hump height (nm). As a result, it was confirmed that there is no possibility that the hump height will increase by increasing the discharge flow rate.

In the above, in order to reduce the hump height, the coating device 1 of the present invention may rotate the wafer W at a rotation speed of 2300 rpm or more when the removal liquid is discharged from the removal liquid nozzle 3. .. Further, in the coating device 1, the following (a) to (g) can be appropriately combined.
(A) Performing the first step and the second step (b) Performing the cleaning step (c) Repeating the first step and the second step multiple times,
(D) The angle θ formed by the tangent line of the removing liquid nozzle 3 is set within 6 degrees (e) The angle Z formed by the removing liquid nozzle 3 with the wafer surface is set to 20 degrees or less (f). The discharge port 30 diameter A of the removal liquid nozzle 3 is set to 0.15 to 0.35 mm (g) The discharge flow rate of the removal liquid from the removal liquid nozzle 3 is set to 20 ml / min to 60 ml / min.

In the above, the coating device 1 can also perform the EBR treatment on the wafer W on which the coating film is formed in the external device. That is, the above-mentioned coating device 1 may be configured as a dedicated device that performs only the EBR processing, and in this case, it is not necessary to provide the coating liquid nozzle 41 and the solvent nozzle 42. The coating liquid is, for example, a resist liquid, a SOD material, an SOC material, a SiARC material, a BARC material, an organic film containing carbon as a main component, or the like in which the components of the coating film are dissolved in a solvent, and the coating film is softened by the solvent. It can be applied to various coating films.

By the way, for example, in order to form a NAND type flash memory in which wiring is formed in a large number of layers called 3D NAND, a coating film such as a resist film is formed on a wafer W on which a large number of films are laminated by a coating device. May be done. Each wafer W transported to the coating apparatus with such a large number of films formed is warped so as to have different shapes due to the influence of the processing performed so far and the stress received from each film. There are cases where it is.

Since the spin chuck 11 of the coating device 1 adsorbs only the central portion of the wafer W, the wafer W having a warp when conveyed is processed in a warped state. Under such circumstances, it is preferable that the removal liquid nozzle 3 of the coating device 1 is configured so that the accuracy of the EBR treatment does not decrease due to this warp. Specifically, in order to suppress the deviation of the distance from the end of the wafer W to the supply position P (see FIG. 3) even if the wafer W has a warp, and to prevent the cut width from deviating from the set value. The angle θ of the removing liquid nozzle 3 described with reference to FIG. 3 is set to a value close to 0 °, specifically, for example, 0 ° to 5 °, and more preferably set to, for example, 0 ° to 3 °. As a supplement to the cut width, the cut width is the width of the annular region on the surface of the wafer W where the coating film is removed by the removal liquid discharged from the removal liquid nozzle 3.

Further, with respect to the angle Z described with reference to FIG. 4, the closer to 90 °, the more the deviation between the ejection position set due to the warp of the wafer W and the actual ejection position is suppressed, and the cut width is less affected by the warp. However, when the removal liquid is discharged to the wafer W rotating at a relatively high speed as described above, the closer the angle Z is to 0 °, the more the pressure when the removal liquid lands on the wafer W can be suppressed. The effect of suppressing the splash of the removing liquid on the surface of the wafer W is enhanced. Therefore, when the angle θ is set to 0 ° to 5 ° as described above, the angle Z is preferably set to 5 ° to 20 °.

The evaluation test conducted to confirm the appropriate values for the above angles θ and Z will be described in detail later. In this evaluation test, the amount of warpage of the wafer W is measured in advance before the test is performed, and the measurement of the amount of warpage will be described with reference to FIG. In FIG. 20, the front surface of the wafer W is shown as W1 and the back surface is shown as W2. In the figure, 51 is a mounting portion of the wafer W, and the wafer W is mounted so that only the peripheral portion of the wafer W is supported from below. In the figure, 52 is a laser displacement meter, and in order to measure the height of each part of the upper surface of the wafer W mounted on the mounting portion 51, the upper part of the wafer W can be moved laterally with respect to the wafer W. It is composed of.

As shown in FIG. 20A, the height of each part in the surface W1 of the wafer W is acquired in a state where the wafer W is placed on the mounting part 51 so that the surface W1 faces upward, and the acquired parts of each part are obtained. Obtain the amount of warpage (referred to as the amount of warpage on the surface side) from the height. Further, as shown in FIG. 20B, the height of each part in the back surface W2 of the wafer W is acquired in a state where the wafer W is placed so that the back surface W2 faces upward, and the height of each portion acquired is used. Acquires the amount of warpage (referred to as the amount of warpage on the back side). Then, the average value of the amount of warpage on the front surface side and the amount of warpage on the back surface side is taken as the amount of warpage of the wafer W. Since only a part of the in-plane of the wafer W is supported by the mounting portion 51 and the wafer W is deformed by its own weight, the amount of warpage of the wafer W is based on the amount of warpage on the front surface side and the amount of warpage on the back surface side. By calculating, the measurement error due to the weight is canceled. Regarding the amount of warpage on the surface side, for example, the heights of a plurality of points in the surface W1 are measured, the heights of the reference planes are calculated from the heights of all the acquired points by the minimum square method, and the heights of the reference planes are calculated with respect to the reference planes. It is calculated as the sum of the distance from the height of the highest point among the measured points and the distance from the height of the lowest point among the measured points with respect to the reference plane. The amount of warpage on the back surface side is calculated by the same method as the method for calculating the amount of warpage on the front surface side.

In the evaluation test described later, as shown in FIG. 20, when the surface of the wafer W is turned upward, the wafer W whose peripheral edge is higher than the height of the central portion on the entire circumference of the wafer W is a concave wafer. Described as W. Further, a wafer W in which the height of the peripheral portion is lower than the height of the central portion on the entire circumference of the wafer W when the surface of the wafer W is turned upward is referred to as a convex wafer W. Further, a wafer W that is warped so that the height of the peripheral edge of the wafer W is located above and below the center of the wafer W when viewed along the circumferential direction of the wafer W is described as a concave-convex wafer W. do.

(Evaluation test 8)
As an evaluation test 8, wafers W having different warpage amounts are subjected to EBR processing by setting the cut width to 1 mm, and after the processing, the cut widths at a plurality of locations around the wafer W are measured and the average value of the cut widths is calculated. did. This EBR treatment was performed using one of the three removal liquid nozzles 3 in which the combinations of the angles θ and the angles Z were set so as to be different from each other. One of the three removal liquid nozzles 3 is set to θ = 0 ° and Z = 10 °, and the nozzle is set to 3-1. One of the removal liquid nozzles 3 is set to θ = 8.5 ° and Z = 30 °, and the nozzle is set to 3-2. The remaining one of the removal liquid nozzles 3 is set to θ = 30 ° and Z = 30 °, and the nozzle is set to 3-3. The wafer W has no warp, that is, the warp amount is 0 μm, the concave wafer W in FIG. 20 above has a warp amount of 196 μm, and the convex wafer W has a warp amount of 232 μm. A test was conducted.

The graph of FIG. 21 shows the result of the evaluation test 8. The horizontal axis of the graph indicates the amount of warpage of the wafer W (unit: μm), and the amount of warpage of the concave wafer W is marked with + and the amount of warpage of the convex wafer W is marked with −. The vertical axis of the graph shows the average value of the cut width (unit: mm). When the nozzle 3-3 is used as shown in the graph, if the wafer W is warped, the average value of the cut width is relatively larger than the set value of 1 mm. When the nozzle 3-2 is used, this deviation is suppressed as compared with the case where the nozzle 3-3 is used. However, the deviation amount between the average value of the cut width and the set value of 1 mm when the warp amount is +196 mm is slightly larger than the practically effective level. When the nozzle 3-1 is used, the average value of the cut width substantially matches the set value of the cut width in all cases where the warp amount is 0 mm, +196 mm, and -232 mm. Therefore, from this evaluation test 8, it was confirmed that it is effective to improve the accuracy of the cut width by using the nozzle 3-1 in the range of the warp amount of the wafer W in the range of +196 μm to -232 μm.

From the results using nozzles 3-2, 3-3, which differ only in the values of θ among the angles θ and Z, by changing the angle θ, the fluctuation of the average value of the cut width due to the warp of the wafer W is suppressed. You can see that you can. When the nozzle 3-1 having θ = 0 is used, the deviation of the average value of the cut width from the set value of the cut width can be sufficiently suppressed. Further, when θ = 8.5 °, the amount of the deviation is slightly large as described above. Therefore, it is considered that the deviation can be sufficiently suppressed if the value is slightly lower than 0 ° or more and 8.5 °, specifically, for example, θ = 0 ° to 5 ° as described above. Further, when the nozzle 3-1 was used, the value of Z was 10 °, and the deviation between the average value of the cut width and the amount of warpage was suppressed, but the value of the angle Z was 30 °. Considering that the deviation is relatively large when 2, 3-3 is used, the angle Z is preferably around 10 °, for example, 5 ° to 20 ° as described above. Conceivable.

(Evaluation test 9)
As the evaluation test 9, the nozzles 3-1, 3-2, or 3-3 used in the evaluation test 8 are used to perform EBR treatment on the concave-convex wafer W having a warp amount of 428 μm, and each of the circumferential directions of the wafer W is subjected to EBR treatment. The EBR cut width at the position was measured, and the maximum value-minimum value was calculated as the variation in the cut width. Also in this evaluation test 9, the set value of the cut width was set to 1 mm.

The graph of FIG. 22 is a plot of the results of the evaluation test 9, and the vertical axis of the graph shows the cut width (unit: mm). The variation in cut width (maximum value-minimum value) is 0.041 mm when the nozzle 3-1 is used, 0.099 mm when the nozzle 3-2 is used, and 0.099 mm when the nozzle 3-3 is used. Is 0.205 mm. When the nozzle 3-1 was used in this way, the variation in the cut width was suppressed most. Therefore, from the evaluation tests 8 and 9, it was confirmed that the accuracy of the cut width can be improved by using the nozzle 3-1 when processing any of the concave wafer W, the convex wafer W, and the concave and convex wafer W. rice field.

(Evaluation test 10)
As an evaluation test 10-1, EBR treatment was performed on a plurality of concave wafers W having a warp amount of 150 μm by changing the angle θ of the removing liquid nozzle 3, and the variation in the cut width was measured. Further, as an evaluation test 10-2, the EBR treatment was performed on a plurality of convex wafers W having a warp amount of 250 μm by changing the angle θ of the removing liquid nozzle 3, and the variation in the cut width was measured. In the evaluation tests 10-1 and 10-2, the removing liquid nozzle 3 is arranged as shown by the solid line in FIGS. 3 and 23 described above, and the removing liquid is discharged from the inside to the outside of the plan view wafer W. In addition to setting the angle θ to discharge, the removal liquid nozzle 3 is arranged as shown by the alternate long and short dash line in FIG. 23, and the angle θ is such that the removal liquid is discharged from the outside to the inside of the wafer W. Is set and the test is conducted. In this evaluation test 10, when θ is set so that the discharge direction of the removing liquid is directed from the inside to the outside of the wafer W, a + sign is given to the numerical value of the angle θ, and the discharge direction is outside the wafer W. When the angle θ is set so as to go inward from the direction, the numerical value of the θ is indicated by a minus sign. In FIG. 23, the tangent line of the wafer W passes through L1 and the supply position P (the liquid landing position on the wafer W of the liquid discharged from the removing liquid nozzle 3), and the line parallel to the tangent line L1 is indicated by L. ..

The graphs of FIGS. 24 and 25 show the results of the evaluation tests 10-1 and 10-2, respectively. The vertical axis of each graph shows the variation in cut width (unit: mm), and the horizontal axis of the graph shows the angle θ. As shown in the graph, the variation in the cut width increases as the absolute value of the angle θ increases. In practice, it is particularly preferable to suppress this variation in cut width to 0.1 mm or less. In both the evaluation tests 10-1 and 10-2, when the angle θ is in the range of -3 ° to + 3 °, the variation in the cut width is 0.1 mm. Therefore, it was confirmed that in the range of the warp amount of the wafer W in the range of +150 μm to −250 μm, the variation in the cut width can be suppressed by setting the angle θ within such a range. When the angle θ is −, the removing liquid may move to the center side of the wafer W from the supply position P, and the cut width may deviate from the desired value. Therefore, the angle θ is preferably 0 ° or more. .. Therefore, the angle θ is preferably 0 ° to + 3 °.

1 Coating device 11 Spin chuck 21 Rotation mechanism 3 Removal liquid nozzle 30 Discharge port 7 Control unit W Wafer P Supply position

Claims (13)

In a coating film removing device that removes the peripheral edge of a coating film formed by supplying a coating liquid to the surface of a circular substrate with a removing liquid.
A rotation holding part that holds and rotates the board,
A removal liquid nozzle that discharges the removal liquid so that the removal liquid is directed to the downstream side in the rotation direction of the substrate is provided on the peripheral edge of the surface of the substrate held by the rotation holding portion.
It is equipped with a control unit that outputs a control signal so that the substrate rotates at a rotation speed of 2300 rpm or more when the removal liquid is discharged .
The control unit
With the substrate rotated at the first rotation speed of 2300 rpm or more, the coating film is cut so that the supply position of the removal liquid is closer to the center of the substrate than the peripheral edge position of the surface of the substrate. The first step of discharging the removal liquid from the removal liquid nozzle while moving it to the position,
A coating film removal characterized by outputting a control signal for executing a second step of moving away from the cut position toward the peripheral edge of the substrate within 1 second after the supply position reaches the cut position. Device. The control unit
After the second step, the supply position is set between the cut position and the peripheral edge position, or at the peripheral edge position, and the substrate is rotated at a second rotation speed lower than the first rotation speed. The coating film removing device according to claim 1 , wherein a control signal for executing a step of discharging the removing liquid from the removing liquid nozzle is output while the removal liquid nozzle is being used. The coating film removing device according to claim 2 , wherein the second rotation speed is set to 500 to 2000 rpm. The control unit
The coating film removing device according to claim 1 , further comprising outputting a control signal for repeating the first step and the second step a plurality of times. When viewed on a flat surface, the angle between the straight line connecting the discharge port of the removal liquid nozzle and the supply position and the tangent line of the substrate at the supply position is set within 6 degrees. The coating film removing device according to any one of claims 1 to 4 . One of claims 1 to 5 , wherein the angle formed by the straight line connecting the removal liquid nozzle and the supply position and the surface of the substrate when viewed in a vertical direction is set to 20 degrees or less. The coating film removing device according to item 1. The coating film removing device according to any one of claims 1 to 6 , wherein the diameter of the discharge port of the removing liquid nozzle is set to 0.15 to 0.25 mm. The coating film according to any one of claims 1 to 7 , wherein the discharge flow rate of the removing liquid when the supply position moves from the peripheral portion to the cut position is set to 55 ml / min or more. Removal device. In a coating film removing method for removing the peripheral edge of a coating film formed by supplying a coating liquid to the surface of a circular substrate with a removing liquid.
The process of holding the board horizontally in the holding part,
Next, in a state where the substrate is rotated at a rotation speed of 2300 rpm or more, the removal liquid is discharged from the removal liquid nozzle to the peripheral edge of the surface of the substrate so as to be toward the downstream side in the rotation direction of the substrate. Including
In the removal liquid discharge step, the supply position of the removal liquid nozzle is set from the peripheral edge position on the surface of the substrate to the center of the substrate rather than the peripheral edge position in a state where the substrate is rotated at the first rotation speed of 2300 rpm or more. The first step of discharging the removal liquid from the removal liquid nozzle while moving it to the cut position of the coating film closer to the portion, and the substrate from the cut position within 1 second after the supply position reaches the cut position. A method for removing a coating film , which comprises a second step of separating from the peripheral side of the coating film. After the second step, the supply position is set between the cut position and the peripheral edge position, or the peripheral edge position, and the substrate is rotated at a second rotation speed lower than the first rotation speed. The coating film removing method according to claim 9 , further comprising a step of discharging the removing liquid from the removing liquid nozzle while allowing the removal liquid to be discharged. The coating film removing method according to claim 10 , wherein the second rotation speed is 500 to 2000 rpm. The coating film removing method according to claim 9 , wherein the first step and the second step are repeated a plurality of times. A storage medium for storing a computer program used in a coating film removing device that removes the peripheral edge of a coating film formed by supplying a coating liquid to the surface of a circular substrate with a removing liquid.
The computer program is a storage medium in which a group of steps is set up to execute the coating film removing method according to any one of claims 9 to 12 .

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