JPH11265871A - Cleaning treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning treatment method which is capable of superior treatment from immediately after a cleaning treatment has started, and does not delay a cleaning treatment time. SOLUTION: In this method, a megasonic nozzle 25 which is constituted movably between a standby position square and the upper part of a wafer retained by a spin chuck 22 is moved to the upper part of the wafer W, pure water to which ultrasonic vibration is applied is supplied to the surface of the wafer W from the megasonic nozzle 25, and cleaning treatment is performed. While the megasonic nozzle 25 moves from the standby position square to the peripheral part (the position of a megasonic nozzle 25'' in the figure) of the wafer W, pure water is supplied beforehand to the surface of the wafer W by a nozzle 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning method for supplying a processing liquid to a substrate such as a semiconductor wafer or an LCD glass plate to perform a cleaning process.

[0002]

2. Description of the Related Art Generally, in a semiconductor device manufacturing process, for example, cleaning is performed to remove contamination such as particles, organic contaminants, and metal impurities attached to the surface of a semiconductor wafer (hereinafter, referred to as "wafer"). Processing system is used. As one of the cleaning processing systems for cleaning a wafer, a single-wafer cleaning processing system using a spin-type device is generally known.

[0003] The cleaning method performed in the single-wafer cleaning system includes a processing body provided with a member such as a brush or a sponge in order to effectively remove particles adhering to the wafer surface. Scrub cleaning in which the wafer surface is rotated while contacting the wafer surface, jet nozzle cleaning in which a high-pressure processing liquid is supplied to the wafer surface, and megasonic cleaning in which a processing liquid subjected to ultrasonic vibration is supplied to the wafer surface are known. Have been.

Here, in megasonic cleaning, pure water is used as a treatment liquid, and a vibration force is applied to water molecules in the pure water by ultrasonic waves. Then, the pure water supplied to the surface of the wafer can effectively shake off particles from the surface of the wafer by the vibration force. As described above, megasonic cleaning is widely used because the effect of the cleaning process can be expected.

[0005]

By the way, the vibration by the ultrasonic wave is transmitted to the surface of the wafer through the liquid. However, in the conventional cleaning processing method, since the pure water with the vibration is supplied in a state where the wafer is first dried, the vibration force in the liquid is not transmitted to the surface of the wafer immediately after the cleaning processing is started. Sometimes. Therefore, in the conventional cleaning method, the original effect of megasonic cleaning cannot be exhibited immediately after the start of the cleaning process.
As a method to compensate for the low cleaning effect immediately after the start of the cleaning process, it is conceivable to increase the cleaning process time.
This causes a decrease in throughput.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a cleaning method capable of performing a cleaning process immediately after the start of the cleaning process without delaying the cleaning process time.

[0007]

According to a first aspect of the present invention, there is provided a cleaning process for supplying a vibrating processing solution to a surface of a substrate held by a holding means to perform a cleaning process. The method is characterized in that before supplying the vibrated treatment liquid to the surface of the substrate, the treatment liquid is supplied to the surface of the substrate in advance.

According to this cleaning method, the processing liquid is supplied to the surface of the substrate in advance, and a liquid film is formed on the surface of the substrate by the processing liquid. Then, the processing liquid supplied to the surface of the substrate immediately after the start of the cleaning process transmits vibrations in the liquid to the surface of the substrate via a previously formed liquid film of the processing liquid. Then, a vibration force is applied to water molecules around the substrate to remove particles from the surface of the substrate. Thus, particles adhering to the surface of the substrate can be satisfactorily removed immediately after the start of the cleaning processing, and the cleaning processing time is not delayed.

According to a second aspect of the present invention, a supply means configured to be movable from a standby position to a position above the substrate held by the holding means is moved above the substrate and supplied to the surface of the substrate. In a cleaning processing method for supplying a vibration-treated processing liquid from a means to perform a cleaning processing, the processing liquid is supplied to a surface of the substrate in advance before the supply means moves above the substrate.

According to such a cleaning method, before the supply means moves above the substrate, the processing liquid is uniformly supplied to the surface of the substrate. Therefore, a good cleaning process can be started immediately after the supply means is moved above the substrate.

In this case, it is preferable that the processing liquid is previously supplied to the surface of the substrate while the supply means is moving above the substrate from the standby position.
According to this configuration, the processing liquid is supplied to the surface of the substrate while the supply unit moves from the standby position to above the substrate. As described above, since the step of moving the supply unit and the step of supplying the processing liquid to the surface of the substrate are performed simultaneously, the cleaning processing time can be reduced. Note that, for example, the processing liquid may be supplied to the surface of the substrate in advance from the stage where the supply unit is waiting at the standby position.

In this case, as described in claim 4, when supplying the vibrated treatment liquid, the supply means is rotated at least from the center of the surface of the substrate to an arbitrary peripheral portion while rotating the substrate. It is preferable to move. According to such a cleaning processing method, it is possible to supply a processing liquid having a uniform vibration applied to the entire surface of the substrate.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in which a wafer as a substrate is carried in a carrier unit, the wafers are washed and dried one by one, and the wafer is carried out in a carrier unit. A description will be given based on the cleaning system performed. FIG. 1 is a plan view of a cleaning system 1 for explaining the present embodiment.

The cleaning system 1 is provided with a mounting portion 2 on which four carriers C containing wafers W can be mounted. At the center of the cleaning processing system 1,
And a take-out arm 3 for taking out the wafers W before the processing step one by one from the carrier C placed on the carrier C and storing the wafers W after the processing step in the carrier C. A transfer arm 4 serving as a transfer mechanism is provided on the back of the unloading arm 3 for exchanging wafers W with the unloading arm 3.
Is waiting. The transfer arm 4 includes the cleaning system 1
Are provided so as to be movable along a transport path 6 provided at the center of the image forming apparatus. Various processing devices are arranged on both sides of the transport path 6. Specifically, on one side of the transport path 6,
For example, a surface treatment device 7 for cleaning the front surface of the wafer W and a back surface treatment device 8 for cleaning the back surface of the wafer W are arranged side by side. On the other side of the transport path 6, four heating devices 9 are provided in a stacked manner. The heating device 9 is a means for heating and drying the wafer W. Two wafer reversing devices 10 are stacked adjacent to the heating device 9.

Here, the configuration of the surface treatment apparatus 7 provided in the cleaning system 1 will be described. FIG. 2 is a perspective view of the surface treatment device 7. FIG. 3 is a sectional view of the internal structure of the surface treatment apparatus 7, and FIG. 4 is a plan view thereof.
The surface treatment device 7 performs scrub cleaning in which a treatment object such as a brush or sponge is brought into contact with the surface of the wafer W to perform cleaning.
The configuration is such that megasonic cleaning for supplying the processing liquid vibrated by ultrasonic waves to the surface of the wafer W is used in combination.

That is, as shown in FIG. 2, FIG. 3, and FIG. 4, the surface treatment device 7 includes a spin chuck 22 that is rotated by a motor 21 while holding the wafer W horizontally by suction at substantially the center of the case 20. , This spin chuck 2
2 and a cup 23 surrounding the wafer W and preventing the processing liquid and the like supplied to the surface of the wafer W from scattering around, and the wafer W rotated by the spin chuck 21.
Scrubber 24 for cleaning the surface of the case and case 2
0, a megasonic nozzle 25 disposed symmetrically with the scrub cleaner 24 with the spin chuck 22 interposed therebetween, and a wafer W held by the spin chuck 22.
And a nozzle 26 for supplying pure water as a processing liquid to the surface of the nozzle. As shown in the figure, an opening / closing door 27 is provided on the wall surface of the case 20 so as to move up and down when the wafer W is carried in and out of the surface treatment apparatus 7.

As shown in FIG.
Has a configuration in which the processing body 30 is mounted on the tip of the scrub arm 31. As shown in FIG. 3, a shaft 32 is provided below the tip of the scrub arm 31 so as to be able to move up and down and rotate by operating a not-shown elevating and rotating mechanism. The processing body 30 is fixed to the lower end of this shaft 32. , Vertically moving and rotationally driven. Also,
The processing body 30 has a member 33 made of a brush, a sponge, or the like attached to the lower surface thereof, and by rotating the processing body 30 to bring the member 33 into contact with the surface of the wafer W,
The surface of the wafer W is cleaned. Note that a pure water supply path may be connected to the processing body 30, and the processing body 30 may be brought into contact with the surface of the wafer W while discharging pure water from the lower center of the member 33.

The base end of the scrub arm 31 is supported on the upper end of a rotatable drive mechanism 35 as shown in FIG. By rotating the scrub arm 31 by the rotation operation of the drive mechanism 35, the processing body 30 disposed at the tip thereof is moved between the standby position A and the upper side of the surface of the wafer W as shown in FIG. It is configured to be freely rotatable (θ direction). In this case, the scrub cleaning machine 24 shown in FIG.
4 shows a state in which the rotating member 33 is brought into contact with the surface of the wafer W by operating the shaft 32 to operate, and the scrub cleaning machine 24 shown in FIG. Indicates a state retracted from the cup 23 to the standby position A.

As shown in FIG. 2, the megasonic nozzle 25 has a nozzle body 41 at the tip of the megasonic arm 40.
Is provided. The nozzle body 41 is connected to a pure water supply path 43 having a valve 42 and supplying pure water as a processing liquid. Further, a vibrator 44 for vibrating pure water with ultrasonic waves is built in the nozzle body 41. In this case, pure water given ultrasonic vibration
Compared to pure water, it has an effect of efficiently removing particles attached to the surface of the wafer W. Thus, the megasonic nozzle 25 is configured to supply the pure water from the pure water supply path 43 toward the surface of the wafer W after applying the ultrasonic vibration.

As shown in FIG. 2, the base end of the megasonic nozzle 25 is supported on the upper end of a vertically movable and rotatable drive mechanism 45. By rotating the megasonic arm 40 by the rotational operation of the drive mechanism 45, the nozzle main body 41 disposed at the tip thereof is moved between the standby position B and the upper side of the surface of the wafer W as shown in FIG. , So as to be freely rotatable (θ ′ direction). Also, the megasonic arm 40 and the nozzle body 41 at the tip thereof move up and down integrally by the raising and lowering operation of the drive mechanism 45.

As shown in FIG. 4, the megasonic nozzle 25 'indicated by a two-dot chain line has been moved to the center of the surface of the wafer W by the operation of the drive mechanism 45. Megasonic nozzle 2 shown by a two-dot chain line in FIG.
5 ”indicates a state where the wafer W has been moved to the peripheral edge of the wafer W by the operation of the drive mechanism 45. In the cleaning process, pure water is uniformly supplied to the surface of the wafer W. The megasonic nozzle 25 is connected to at least the wafer W
4 is reciprocated from the center of the surface (the position of the megasonic 25 'in FIG. 4) to the peripheral portion of the wafer W (the position of the megasonic 25 "in FIG. 4).
The megasonic nozzle 25 indicated by the solid line in the middle shows a state in which the drive mechanism 45 operates to retract from the cup 23 to the standby position B.

The nozzle 26 supplies pure water to the surface of the rotating wafer W held by the spin chuck 25. In the nozzle 26, the wafer W
Is set so as to discharge the pure water toward the center of the wafer W, and the time to supply the pure water is set before the megasonic nozzle 25 is moved above the surface of the wafer W. That is, as shown in FIG.
Is supplied from the standby position B to the peripheral portion of the wafer W (the position of the megasonic nozzle 25 ″ in FIG. 4), and pure water is supplied to the surface of the wafer W to cover the entire surface of the wafer W. A liquid film 47 of pure water is formed.
In this way, by supplying pure water to the surface of the wafer W in advance, the vibration in the pure water supplied from the megasonic nozzle 25 is quickly transmitted to the surface of the wafer W even immediately after the start of the cleaning process. Configuration. Further, since the nozzle 26 supplies pure water simultaneously with the movement of the megasonic nozzle 25, the cleaning processing time is not prolonged. Note that the setting may be made so that pure water can be supplied to the surface of the wafer W before the movement of the megasonic nozzle 25 starts.

Next, the cleaning processing of the wafer W performed in the cleaning processing system 1 configured as described above will be described. First, a transfer robot (not shown) places a carrier C containing, for example, 25 wafers W that have not been cleaned yet, on the placement unit 2. Then, the wafer W is taken out of the carrier C placed on the placing section 2 and delivered to the transfer arm 4 via the take-out / in arm 3. Then, the wafer W is cleaned by using the surface treatment device 7 and the back surface treatment device 8 to remove organic contaminants, particles, and the like adhering to the front and back surfaces of the wafer W.

Here, the cleaning process in the surface treatment device 7 will be described with reference to the flowchart shown in FIG.
First, the transfer arm 4 enters the surface processing apparatus 7 from the opened opening / closing door 27, and transfers the wafer W to the spin chuck 22, as shown in FIG. The transfer arm 4 withdraws from the inside of the surface treatment device 7, and the opening / closing door 27 is closed. Then, the wafer W is sucked and held by the spin chuck 22, and the cleaning process is started by rotating the wafer W integrally with the spin chuck 22 by operating the motor 21 (S1).

During the period before the megasonic nozzle 25 is moved from the standby position B to above the wafer W, the nozzle 26 supplies pure water to the surface of the wafer W in advance,
A liquid film of pure water is formed on the surface of the wafer W (S2).
That is, as shown in FIG. 4, the movement of the megasonic 25 toward the upper side of the wafer W is started until the movement of the megasonic 25 to the peripheral portion of the wafer W (the position of the megasonic nozzle 25 ″ in FIG. 4). Then, pure water is supplied to the surface of the wafer W in advance, and after the megasonic nozzle 25 is moved above the wafer W, the supply of pure water from the nozzle 26 is stopped. Pure water is supplied from the passage 43 to the nozzle body 41, and the vibrator 44 is operated to apply ultrasonic vibration to the pure water.
5 supplies the vibrated pure water toward the surface of the wafer W (S3). Therefore, a good cleaning process can be started immediately after the megasonic nozzle 25 is moved above the wafer W. Since the step of moving the megasonic nozzle 25 and the step of supplying pure water to the surface of the wafer W are performed simultaneously, the cleaning processing time can be reduced. Note that pure water may be supplied to the surface of the wafer W in advance from the stage where the megasonic nozzle 25 is waiting at the standby position b.

With the pure water supplied to the surface of the wafer W immediately after the start of the cleaning process, the vibration in the liquid is transmitted to the surface of the wafer W via the pure water liquid film 47 formed in advance. Then, a vibration force is applied to water molecules around the wafer W, and particles are shaken off from the surface of the wafer W. in this case,
The vibration applied to pure water from the vibrator is from 400 kHz to 2
This is a frequency band of 00 MHz, and fine particles can be removed without damaging the wafer W. Thus, fine particles can be effectively removed immediately after the start of the cleaning process, and the cleaning process time is not delayed.

Further, when supplying pure water with vibration, while rotating the wafer W, as shown in FIG.
The megasonic nozzle 25 is positioned at least from the center of the surface of the wafer W (the position of the megasonic 25 'in FIG. 4).
4 (the position of the megasonic 25 ″ in FIG. 4). This makes it possible to supply pure water with uniform vibration to the entire surface of the wafer W.

Further, as shown in FIG.
The scrub cleaning machine 24 is moved above the wafer W by the operation of, and the member 33 of the processing body 30 is brought into contact with the surface of the wafer W to perform scrub cleaning. After a predetermined time,
Pure water from the megasonic nozzle 25 stops (S
4). Then, the megasonic nozzle 25 and the scrub cleaner 24 are retracted from the cup 23, returned to the respective standby positions A and B, and returned to the standby state. Then, the drying process is performed by rotating the wafer W at a high speed.

After the surface cleaning process is completed,
The opening / closing door 27 is opened, and the wafer W is taken out of the surface treatment device 7 by the transfer arm 4. Then, the reversing device 1
At 0, the wafer W is inverted, and the back surface of the wafer W is cleaned by the back surface processing device 8. Then, the wafer W is transferred to the drying device 9.
For 30 seconds to dry at 100 ° C. The wafer W having undergone the predetermined processing steps is transferred from the transfer arm 4 to the take-out storage arm 3 and stored again in the carrier C. Subsequently, the same processing steps are performed on the remaining 24 wafers W one by one. 25 wafers W
When a predetermined processing step is completed, the carrier is carried out of the cleaning system 1 in units of carriers C.

Thus, according to the present embodiment, before the megasonic nozzle 25 moves above the wafer W, pure water is supplied to the surface of the wafer W in advance, and the liquid film by pure water is supplied to the surface of the wafer W. Since 47 is formed, fine particles can be effectively removed immediately after the start of the cleaning processing, and the cleaning processing time is not delayed. Moreover, megasonic nozzle 25
Is moved simultaneously with the step of supplying pure water to the surface of the wafer W, so that the cleaning processing time can be reduced. Therefore, the efficiency of the cleaning process can be improved without affecting the throughput at all.

Although an example of the embodiment of the present invention has been described, the present invention is not limited to this example but can take various forms. For example, the substrate is not limited to the semiconductor wafer W as in the above-described embodiment, but may be an LCD.
It may be a substrate, a glass substrate, a CD substrate, a photomask, a printed substrate, a ceramic substrate, or the like.

[0032]

EXAMPLE Next, an experiment was conducted on an example of the present invention. The surface treatment apparatus described with reference to FIGS. 2, 3 and 4 was actually prepared, and a comparative experiment was performed to determine how the particle removal rate changes depending on the presence or absence of a pure water liquid film. In each example, only megasonic cleaning was performed, and scrub cleaning was not performed. In addition, as a common condition, a spherical substance having a diameter of about 0.309 μm and made of a resin of polystyrene is used as particles, and 3000 particles are initially attached to the surface of the wafer before the cleaning process. And Further, pure water to which a vibration of 1.5 MHz was given by an ultrasonic vibrator was supplied to the wafer to perform a cleaning process. The particle removal rate was determined as follows, and the results are shown in Table 1.

Particle removal rate = (3000−
A) / 3000 × 100% A: Particle value of wafer after cleaning treatment

[0034]

[Table 1]

The following can be understood from the results shown in Table 1.
In other words, if a liquid film is formed by pure water before performing megasonic cleaning, the particle removal rate can be as good as 81%, and a good result can be obtained. Has a particle removal rate of 75
%. Therefore, it can be understood from the above experiments that the efficiency of the cleaning process is improved by forming a liquid film using pure water in advance.

[0036]

According to the first aspect of the present invention, the processing liquid is supplied to the surface of the substrate in advance, and a liquid film is formed on the surface of the substrate by the processing liquid. Can be effectively removed without delaying the cleaning time. Therefore, the efficiency of the cleaning process can be improved without affecting the throughput at all. as a result,
For example, semiconductor devices can be manufactured smoothly,
The productivity can be improved.

According to the second aspect of the present invention, a good cleaning process can be started immediately after the supply means is moved above the substrate. In particular, in the third aspect, the step of moving the supply means and the step of supplying the processing liquid to the surface of the substrate are performed simultaneously, so that the cleaning processing time can be reduced. Further, in the cleaning method according to the fourth aspect, it is possible to supply a processing liquid having a uniform vibration applied to the entire surface of the substrate.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cleaning system including a surface processing apparatus to which a cleaning method according to an embodiment is applied.

FIG. 2 is a perspective view of a surface treatment apparatus to which a cleaning method according to the embodiment is applied;

FIG. 3 is a cross-sectional view of a surface treatment apparatus to which the cleaning method according to the embodiment is applied;

FIG. 4 is a plan view of a surface treatment apparatus to which the cleaning method according to the embodiment is applied;

FIG. 5 is a flowchart illustrating a cleaning method according to the embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cleaning processing system 7 Surface treatment apparatus 22 Spin chuck 24 Scrub cleaner 25 Megasonic nozzle 26 Nozzle 35, 45 Drive mechanism 44 Transducer I, B Standby position W Wafer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B08B 3/12 B08B 3/12 Z

Claims (4)

[Claims] In a cleaning method for supplying a vibration-treated treatment liquid to a surface of a substrate held by a holding means and performing a cleaning treatment, the vibration-supplied treatment liquid is supplied to the surface of the substrate before the treatment liquid is supplied to the surface of the substrate. A cleaning method comprising supplying a processing liquid to the surface of the substrate in advance. 2. A process in which a supply unit configured to be movable from a standby position to a position above a substrate held by a holding unit is moved above a substrate, and a vibration is applied to the surface of the substrate from the supply unit. A cleaning processing method for supplying a liquid and performing a cleaning processing, wherein a processing liquid is previously supplied to a surface of the substrate before the supply unit moves above the substrate. 3. The cleaning method according to claim 2, wherein the processing liquid is supplied to the surface of the substrate in advance while the supply unit is moving from the standby position to above the substrate. 4. The method according to claim 1, wherein the supply unit is moved from at least a center of a surface of the substrate to an arbitrary peripheral portion while rotating the substrate when supplying the processing liquid subjected to the vibration. Item 4. The cleaning method according to item 2 or 3.