JP2006278956A - Apparatus and method for substrate processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate processing apparatus and a substrate processing method capable of more positively eliminating a foreign matter on the surface of a substrate. <P>SOLUTION: This substrate processing apparatus is provided with a spin chuck 1 for rotating a wafer W while holding it, a processing liquid nozzle 2 for supplying a processing liquid to the wafer W, a scrubbing brush 3 for scrubbing the wafer W, a nozzle transfer mechanism 4 for transferring this scrubbing brush 3, and a standby pot 5. The scrubbing brush 3 is brought into a standby state in the standby pot 5 during standby period when the scrubbing processing for eliminating a foreign matter on the wafer W by the scrubbing brush 3 is not performed. An aqueous ammonia as an alkaline liquid is supplied to the standby pot 5, and an alkaline liquid reservoir unit is provided in the inside of the standby pot 5. An ammonia gas is generated due to volatilization of the aqueous ammonia stored by this alkaline liquid reservoir unit, and the ammonia gas is supplied to the scrubbing brush 3 in a standby state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate processing apparatus and a substrate processing method for removing foreign substances from a surface of a substrate by scrubbing the surface of the substrate with a scrub brush. Substrates to be processed include, for example, semiconductor wafers, glass substrates for liquid crystal display devices, glass substrates for plasma displays, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, and the like. .

  In a semiconductor device manufacturing process, it is indispensable to clean the substrate (semiconductor wafer) between the processes. A single-wafer type substrate processing apparatus that cleans substrates one by one includes, for example, a substrate holding and rotating mechanism that holds and rotates a substrate substantially horizontally, and the surface of the substrate that is held and rotated by the substrate holding and rotating mechanism. A scrubbing-like scrubbing brush and a treatment liquid nozzle for supplying a cleaning chemical (ammonia water or ammonia hydrogen peroxide solution mixed solution) to the substrate held and rotated by the substrate holding and rotating mechanism. .

  The scrub brush is attached to, for example, the tip of a swing arm that swings horizontally around a rotation axis arranged outside the rotation region of the substrate. When the swing arm is driven with the scrub brush pressed against the rotating substrate surface, the scrub brush scrubs while scanning the substrate surface. Thereby, the foreign material of the whole substrate surface can be removed.

While such a scrub cleaning process is performed on a large number of substrates, foreign substances on the substrate are transferred and accumulated on the scrub brush. In order to suppress this, when a standby period occurs during which the substrate to be processed is not supplied for a relatively long time, the scrub brush is washed with water. Specifically, a scrub brush standby position is set outside the substrate rotation region, and a cleaning pot is provided at this standby position. The cleaning pot is a cylindrical container that can accommodate a scrub brush, and a pure water nozzle that supplies pure water to the scrub brush is disposed therein, and a drain pipe is connected to the bottom surface. With this configuration, during the standby period, pure water can be supplied from the pure water nozzle to the scrub brush, and foreign matter adhering to the scrub brush can be washed away.
JP-A-8-10719

However, according to the research of the present inventor, surprisingly, the substrate (first substrate) that was first processed by the scrub brush that had been subjected to the water washing process during the standby period was the substrate ( Compared to the second and subsequent substrates, a phenomenon in which a large number of foreign matters (particles) remain is clearly confirmed.
The inventor of the present application predicted that the above phenomenon was caused by a change in the zeta potential of the foreign matter adhering to the scrub brush.

The zeta potential of the substrate (semiconductor wafer) is generally negative. Therefore, in order to make it easy to peel off the foreign substance from the substrate, it is effective to control the zeta potential of the foreign substance to be negative. For this purpose, in the scrub cleaning process, ammonia water or ammonia hydrogen peroxide solution mixed solution is supplied to the substrate surface as a cleaning chemical solution.
However, the scrub brush that has been supplied with pure water in the washing pot has a low pH. When the scrub brush in such a state is pressed against the substrate surface, the zeta potential of the foreign matter in contact therewith becomes positive, and it is considered that such a foreign matter is difficult to remove from the substrate surface. Thereafter, as the scrub cleaning process is repeated while supplying the alkaline cleaning chemical solution, the scrub brush becomes rich in the alkaline cleaning chemical solution, thereby eliminating the above-described situation.

With such a mechanism, it is presumed that an apparent cleaning defect was observed on the first substrate after the end of the standby period.
An object of the present invention is to provide a substrate processing apparatus and a substrate processing method that can more reliably remove foreign substances on the substrate surface.

  In order to achieve the above object, the invention according to claim 1 includes a substrate holding mechanism (1) for holding the substrate (W) and a surface of the substrate held by the substrate holding mechanism to scrub the foreign matter on the substrate surface. A scrubbing brush (3) for removing water and an alkaline gas supply mechanism (5, 22, 24, 32, for supplying an alkaline gas to the surface of the scrubbing brush when the scrubbing brush is not scrubbing the substrate) 45). The alphanumeric characters in parentheses indicate corresponding components in the embodiments described later. The same applies hereinafter.

  According to this configuration, during standby, by supplying alkaline gas to the surface of the scrub brush, the surface of the scrub brush and the zeta potential of the foreign matter attached to the surface are controlled to be negative. Therefore, when the scrubbing brush comes into contact with the substrate after the end of the waiting period, it can be avoided that the zeta potential of the foreign matter on the substrate (generally the zeta potential is negative) becomes positive, and the foreign matter on the substrate is peeled off. It will not be difficult. Further, since not only the foreign matter on the surface of the scrub brush but also the zeta potential of the scrub brush itself is controlled negatively, the foreign matter does not adhere firmly to the scrub brush, and when scrubbing the substrate, the scrub brush Accumulation of foreign matter on the surface of the can be suppressed.

The alkaline gas is a gas capable of negatively controlling the zeta potential of the scrub brush and the foreign matter adhering to the surface thereof. More specifically, the pH of the surface of the scrub brush is set to 9 or more. A gas that can be controlled. An example of such an alkaline gas is ammonia. Since ammonia water is a volatile aqueous solution that generates ammonia gas by volatilization, ammonia gas generated by volatilization from ammonia water of an appropriate concentration (for example, pH 10 or more) is supplied to the scrub brush as an alkaline gas. Also good. Further, the aqueous solution is not limited to ammonia water, and may be an aqueous solution containing at least one ion of NH ₄ +, RNH ₃ +, R ₂ NH ₂ +, R ₃ NH +, and R ₄ N +. “R” represents an alkyl group.

The substrate holding mechanism may be a substrate holding and rotating mechanism that holds and rotates a substrate.
The invention described in claim 2 further includes a processing liquid supply mechanism (2) for supplying a processing liquid to the surface of the substrate when the substrate is scrubbed with the scrub brush. This is a substrate processing apparatus.
According to this configuration, the foreign matter removed from the substrate surface by the scrub brush can be washed out of the substrate by the processing liquid. Further, when an alkaline gas is supplied to the scrub brush that has been wetted by the treatment liquid during standby, the vicinity of the surface of the scrub brush is kept wet by the alkaline liquid. Thereby, the scrub cleaning process after the end of the standby period can be performed efficiently.

As the treatment liquid, an alkaline liquid is preferable, and specifically, ammonia water or ammonia hydrogen peroxide solution mixed liquid is preferable. By using such a treatment liquid, the zeta potential of the foreign matter on the substrate can be negatively controlled, so that the foreign matter can be efficiently removed from the substrate surface. In addition, the treatment solution is not limited to ammonia water or ammonia hydrogen peroxide solution mixture, and is an aqueous solution containing at least one ion of NH ₄ +, RNH ₃ +, R ₂ NH ₂ +, R ₃ NH +, and R ₄ N +. It may be.

  The invention according to claim 3 further includes a brush moving mechanism (4) for moving the scrub brush between a processing position for scrubbing the substrate surface and a standby position retracted from the processing position, and the alkaline gas The substrate processing apparatus according to claim 1, wherein the supply mechanism supplies an alkaline gas to the scrub brush at the standby position.

According to this configuration, since the scrub brush is moved between the processing position and the standby position by the brush moving mechanism, an alkaline gas can be supplied to the scrub brush at the standby position with a simple configuration.
A fourth aspect of the present invention is the substrate processing apparatus according to the third aspect, further comprising a cleaning liquid supply mechanism (21, 23, 38) for supplying a cleaning liquid to the scrub brush at the standby position.

  According to this configuration, the scrub brush can be cleaned at the standby position, so that foreign matter adhering to the scrub brush can be removed. At the same time, since the alkaline gas is supplied to the scrub brush at the standby position, the zeta potential of the foreign matter slightly remaining on the scrub member and its surface can be controlled negatively. Thereby, the substrate can be cleaned more efficiently.

Further, the scrub member can be kept wet by the cleaning liquid, and the scrub member is kept wet by the alkaline liquid by supplying an alkaline gas to the scrub member in that state. . This enables efficient scrub cleaning of the substrate immediately after the end of the standby period.
As the cleaning liquid, at least one of pure water, reduced water (hydrogen water), and electrolytic ion water (particularly alkaline ion water) can be used. Here, particularly when reduced water (hydrogen water) or alkaline ionized water is used as the cleaning liquid, the zeta potential of the scrub member and the foreign matter slightly remaining on the surface thereof can be more reliably controlled to be negative.

The invention according to claim 5 is characterized in that the alkaline gas supply mechanism includes an alkaline liquid storage unit (32, 45) for storing a volatile alkaline liquid that volatilizes to generate an alkaline gas below the standby position. The substrate processing apparatus according to claim 3 or 4.
According to this configuration, the alkaline liquid is stored in the alkaline liquid storage section, and the alkaline gas generated by the volatilization of the alkaline liquid is supplied to the scrub brush. In such a configuration, the consumption of the alkaline liquid is remarkably reduced as compared with the case where the alkaline liquid is directly supplied to the scrub brush, so that the running cost can be kept low.

  The “volatile alkaline liquid” may be volatile at room temperature (for example, 23 ° C.) like ammonia water, or a liquid that volatilizes alkaline gas by heating to a temperature higher than room temperature. There may be. If heating is required for volatilization, a heating mechanism for heating the alkaline liquid reservoir may be provided, or a high-temperature alkaline liquid preheated outside the alkaline liquid reservoir may be supplied to the alkaline liquid reservoir. Good.

Since the concentration of the alkaline liquid gradually decreases due to volatilization, it is preferable to further include an alkaline liquid supply mechanism (22, 24, 40) that supplies the alkaline liquid to the alkaline liquid reservoir as required.
The invention described in claim 6 further includes a liquid receiving member (48) disposed above the alkaline liquid reservoir and suppressing or preventing mixing of other liquids into the alkaline liquid reservoir. Item 6. The substrate processing apparatus according to Item 5.

According to this configuration, since the liquid receiving member that prevents the mixture of other liquids (liquids other than the alkaline liquid) into the alkaline liquid storage part is provided, the alkaline liquid in the alkaline liquid storage part is inadvertently diluted. There is no. Thereby, a required amount of alkaline gas can be reliably supplied to the scrub brush.
In particular, this configuration is preferably employed when a cleaning liquid supply mechanism for supplying a cleaning liquid to the scrub brush is provided. Thereby, dilution of the alkaline liquid by the cleaning liquid can be suppressed or prevented.

  According to a seventh aspect of the present invention, a scrubbing step of scrubbing the surface of the substrate with a scrubbing brush to remove foreign matter on the surface of the substrate, and a surface of the scrubbing brush during standby when the substrate is not scrubbed with the scrubbing brush. An alkaline gas supply step of supplying an alkaline gas and negatively controlling a zeta potential of the scrub brush and the foreign matter adhering to the scrub brush.

By this method, the same effect as that of the invention of claim 1 can be obtained.
The invention according to claim 8 is the substrate processing method according to claim 7, further comprising a processing liquid supply step of supplying a processing liquid to the surface of the substrate in parallel with the scrubbing step.
By this method, the same effect as that of the invention of claim 2 can be obtained.
A ninth aspect of the present invention is the substrate processing method according to the seventh or eighth aspect, further comprising a cleaning liquid supplying step of supplying a cleaning liquid to the scrub brush during the standby.

  By this method, an effect similar to that of the invention of claim 4 can be obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an illustrative perspective view for explaining a basic configuration of a substrate processing apparatus according to an embodiment of the present invention. The substrate processing apparatus includes a spin chuck 1 as a substrate holding and rotating mechanism that holds and rotates a semiconductor wafer W (hereinafter referred to as “wafer W”), which is an example of a substrate, substantially horizontally, and is held by the spin chuck 1. A processing liquid nozzle 2 for supplying a processing liquid toward the rotation center of the wafer W, a scrub brush 3 for scrubbing the surface of the wafer W, a brush moving mechanism 4 for moving the scrub brush 3, and a scrub brush 3 and a standby pot 5 for keeping 3 in standby.

  The spin chuck 1 includes a disk-shaped rotating base 6, a rotating shaft 7 that supports the rotating base 6 substantially horizontally and is rotatable about a vertical axis, and a chuck rotation driving mechanism 8 that applies a rotating force to the rotating shaft 7. And. On the upper surface of the rotating base 6, a plurality of chuck pins 9 that stand on the end surface of the wafer W and grip the wafer W are provided upright. With this configuration, the wafer W can be held and rotated in a substantially horizontal state.

  A chemical liquid from a chemical liquid supply source is supplied to the processing liquid nozzle 2 via a chemical liquid valve 11, and pure water (deionized water) from a pure water supply source is supplied via a pure water valve 12. Yes. That is, the chemical liquid can be supplied from the processing liquid nozzle 2 to the wafer W by opening the chemical liquid valve 11, and the pure water can be supplied from the processing liquid nozzle 2 to the wafer W by opening the pure water valve 12. it can. When the processing liquid (chemical solution or pure water) is supplied to the rotation center of the wafer W while the spin chuck 1 is rotated, the processing liquid receives a centrifugal force and spreads over almost the entire upper surface of the wafer W, and the peripheral edge of the wafer W It will flow down from the edge.

  In this embodiment, the chemical liquid supplied from the chemical liquid supply source is an alkaline liquid. More specifically, it is ammonia water or ammonia hydrogen peroxide solution mixture. Other alkaline liquids may be used as long as the wafer W is not adversely affected. However, it is most appropriate to use ammonia water or ammonia hydrogen peroxide solution generally available in a semiconductor manufacturing factory.

  The scrub brush 3 is a sponge-like scrub member made of, for example, PVA (polyvinyl alcohol). The brush moving mechanism 4 for moving the scrub brush 3 includes a swing arm 15 that holds the scrub brush 3 downward at a tip, a support shaft 16 that supports the swing arm 15 substantially horizontally, and the support shaft 16. Is provided with a swing drive mechanism 17 for rotating the support shaft 16 around a vertical axis, and a lift drive mechanism 18 for moving the support shaft 16 up and down. With this configuration, the scrub brush 3 can move in the horizontal direction above the wafer W and can move up and down to contact and separate from the wafer W. When the swing arm 15 is swung while the scrub brush 3 is in contact with the surface of the wafer W during the rotation of the wafer W, the scrub brush 3 moves from the rotation center of the wafer W to the peripheral portion. Scrub while scanning the entire surface of the wafer W.

The swing arm 15 incorporates a brush rotation drive mechanism 20 for rotating the scrub brush 3 around the vertical axis.
The standby pot 5 is a cylindrical container that can receive the scrub brush 3, and pure water as a cleaning liquid for cleaning the scrub brush 3 is supplied from the cleaning liquid supply pipe 21 to control the zeta potential of the scrub brush 3. For this purpose, aqueous ammonia as an alkaline liquid is supplied from an alkaline liquid supply pipe 22. The cleaning liquid supply pipe 21 is connected to a cleaning liquid supply source (pure water supply source) via a cleaning liquid valve 23. The alkaline liquid supply pipe 22 is connected to an alkaline liquid supply source (ammonia water supply source) via an alkaline liquid valve 24. A drainage pipe 25 is connected to the bottom surface of the standby pot 5.

The operations of the chuck rotation drive mechanism 8, the swing drive mechanism 17, the elevation drive mechanism 18 and the brush rotation drive mechanism 20, and the opening and closing of the chemical liquid valve 11, the pure water valve 12, the cleaning liquid valve 23 and the alkaline liquid valve 24 are controlled. It is controlled by the device 30.
FIG. 2 is a schematic cross-sectional view showing a configuration example of the standby pot 5. The standby pot 5 includes a pot body 31 and an alkaline liquid storage part 32 provided in the pot body 31. The pot body 31 is a bottomed cylindrical (cylindrical in this configuration example) container, the upper surface of which is open, and a brush inlet 33 for receiving the scrub brush 3 is formed. The alkaline liquid storage part 32 is configured by a plate-like body arranged substantially horizontally in the pot main body 31 and is attached to an intermediate position in the height direction of the pot main body 31. The pot main body space above the alkaline liquid storage portion 32 forms a scrub brush storage space 34 that can store the entire scrub brush 3, and the pot main body space below the alkaline liquid storage portion 32. Forms the drainage part 35.

An opening 36 is formed at a position facing the lower surface of the scrub brush 3 at the center of the alkaline liquid storage portion 32. That is, the alkaline liquid storage part 32 is comprised by the cyclic | annular plate-shaped body. The scrub brush accommodation space 34 and the drainage part 35 located above and below the alkaline liquid storage part 32 communicate with each other through the opening 36.
A cleaning liquid port 38 to which the cleaning liquid supply pipe 21 is connected is provided at a position above the alkaline liquid storage section 32 in the side wall 37 of the pot body 31. The liquid discharge port 39 of the cleaning liquid port 38 faces the scrub brush 3 at a position (standby position) accommodated in the pot body 31, and discharges pure water as a cleaning liquid to the scrub brush 3. A cleaning liquid nozzle is formed.

  An alkaline liquid port 40 to which the alkaline liquid supply pipe 22 is connected is further provided at a position above the alkaline liquid storage section 32 in the side wall 37 of the pot body 31. From this alkaline liquid port 40, ammonia water as an alkaline liquid is introduced at a small flow rate (so-called slow leak). The introduced ammonia water flows down along the inner wall surface of the pot main body 31 and reaches the alkaline liquid storage section 32. On the upper surface thereof, a liquid film of alkaline liquid (alkaline liquid film; ammonia water film) is formed by surface tension. 41 is formed. The alkaline liquid film 41 is a liquid film having a thickness of about 2 mm, for example, and forms an alkaline liquid pool having a liquid amount of about 3 to 4 cc held by the surface tension on the alkaline liquid reservoir 32. Volatilization of the alkaline liquid film 41 releases alkaline gas (ammonia gas) in the liquid, and this alkaline gas (vapor) is supplied to the scrub brush 3. In addition, when only alkaline vapor | steam is supplied to the scrub brush 3 in this way, since the quantity of the metal impurity contained is small compared with the case where an alkaline liquid is supplied, the metal contamination of the scrub brush 3 is suppressed. There is an effect that. Here, since the alkaline liquid diluted by volatilization is replaced with a new liquid supplied from the alkaline liquid port 40, the concentration of the alkaline liquid film 41 is maintained at a predetermined value.

  When pure water as the cleaning liquid is discharged from the liquid discharge port 39 of the cleaning liquid port 38 to the scrub brush 3, the alkaline liquid film 41 may be diluted by the scattered cleaning liquid. However, even in such a case, when the new liquid is supplied to the alkaline liquid film 41 due to the slow leak from the alkaline liquid port 40, the concentration of the alkaline liquid film 41 is restored to the value before dilution. Thereby, ammonia gas can be reliably supplied to the scrub brush 3.

  Here, the size of the opening 36 is preferably larger than the area of the lower surface of the scrub brush 3. In this way, the pure water discharged from the liquid discharge port 39 of the cleaning liquid port 38 and splashed upon hitting the scrub brush 3 is further suppressed from being mixed into the ammonia water film 41 on the alkaline liquid storage section 32, and the ammonia water Can be prevented from being diluted.

  A drain plate 43 connected to the drain pipe 25 is provided on the bottom plate 42 of the pot body 31. The drain port 43 guides the liquid guided to the drain part 35 to the drain pipe 25. In the drainage part 35, the cleaning liquid discharged from the cleaning liquid port 38 and the alkaline liquid (ammonia water) constituting the alkaline liquid film 41 flow down through the opening 36. These liquids are discharged from the drain port 43 to the drain pipe 25.

Next, the operation of the substrate processing apparatus will be described with reference to FIGS.
The unprocessed wafer W is delivered to the spin chuck 1 by a substrate transfer robot (not shown). When the wafer W is held on the spin chuck 1, the control device 30 controls the chuck rotation drive mechanism 8 to rotate the spin chuck 1. As a result, the wafer W is rotated around the vertical axis while being held in a substantially horizontal posture.

In this state, the control device 30 opens the chemical liquid valve 11 and supplies the processing liquid from the processing liquid nozzle 2 toward the rotation center of the wafer W. The processing liquid receives a centrifugal force on the wafer W, and forms a processing liquid flow from the rotation center of the wafer W toward the outside.
The control device 30 further controls the swing drive mechanism 17 and the lift drive mechanism 18 to guide the scrub brush 3 upward near the rotation center of the wafer W. Thereafter, the control device 30 controls the lift drive mechanism 18 to lower the scrub brush 3 and bring it into contact with the surface of the wafer W. In this state, the control device 30 further controls the swing drive mechanism 17 to move the scrub brush 3 from the rotation center of the wafer W to the peripheral portion thereof. As a result, scrub cleaning is performed while almost the entire surface of the wafer W is scanned.

When the scrub brush 3 reaches the peripheral edge of the wafer W, the control device 30 controls the elevating drive mechanism 18 to raise the scrub brush 3 and separate it from the surface of the wafer W. In this state, the control device 30 further controls the swing drive mechanism 17 to guide the scrub brush 3 to the vicinity of the rotation center of the wafer W.
Thereafter, scrub cleaning of the wafer W is performed by repeating the same operation a predetermined number of times. The foreign matter separated from the surface of the wafer W by scrubbing with the scrub brush 3 is removed to the outside of the wafer W by the processing liquid flow on the wafer W and flows down together with the processing liquid.

The position of the scrub brush 3 when the scrub cleaning process is performed (the position between the rotation center of the wafer W and the peripheral edge thereof) is the processing position of the scrub brush 3.
When the scrub cleaning process is completed, the control device 30 controls the swing drive mechanism 17 and the lift drive mechanism 18 to accommodate the scrub brush 3 in the standby pot 5. The position of the scrub brush 3 when accommodated in the standby pot 5 is the standby position.

Thereafter, the control device 30 closes the chemical liquid valve 11 and opens the pure water valve 12 instead. Thus, pure water is supplied from the processing liquid nozzle 2 toward the rotation center of the wafer W in the rotating state. In this way, the pure water rinse process of the wafer W is performed.
After the pure water rinsing process for a predetermined time, the control device 30 closes the pure water valve 12 to stop the supply of pure water, and controls the chuck rotation driving mechanism 8 to control the rotation speed of the spin chuck to a predetermined drying rate. Increase to speed. Thereby, the drying process which shakes off the water | moisture content of the surface of the wafer W with a centrifugal force is performed.

After the drying process for a predetermined time, the control device 30 controls the chuck rotation drive mechanism 8 to stop the rotation of the spin chuck 1 and releases the gripping of the wafer W by the chuck pins 9. In this state, the processed wafer W is paid out by the substrate transfer robot.
Similar processing is repeatedly performed on a plurality of wafers W.

  The control device 30 always opens the alkaline liquid valve 24 during the operation period of the substrate processing apparatus. Thereby, in the standby pot 5, the state in which the alkaline liquid film 41 is formed in the alkaline liquid storage portion 32 is maintained throughout, and the potion is caused by volatilization of the alkaline gas (ammonia gas in this embodiment) from the alkaline liquid film 41. The inside of the main body 31 is held in a state filled with alkaline gas. As a result, the scrub brush 3 disposed at the standby position (inside the standby pot 5) maintains a pH of 9 or more near the surface thereof, and the zeta potential of the surface of the scrub brush 3 and foreign matter attached to the surface is negative. Will be held.

A plurality of wafers W to be processed are not necessarily loaded into the substrate processing apparatus without interruption, and a relatively long standby period (for example, 2 to 3 hours) may occur between batches. During such a standby period, the scrub brush 3 is held in the standby position (in the standby pot 5).
When an unprocessed wafer W is not loaded into the substrate processing apparatus for a predetermined time or longer (for example, 30 minutes or longer), the control device 30 opens the cleaning liquid valve 23 for a predetermined time. As a result, pure water as the cleaning liquid is discharged from the liquid discharge port 39 of the cleaning liquid port 38 toward the scrub brush 3 accommodated in the pot body 31. As a result, the foreign matter adhering to the scrub brush 3 is washed away, flows down from the opening 36 to the drainage portion 35, and then guided to the drainage pipe 25 via the drainage port 43. Thus, the scrub brush 3 is washed with water during the standby period.

When the scrub brush 3 is washed with water, the control device 30 may control the brush rotation drive mechanism 20 to rotate the scrub brush 3. Thereby, the foreign material adhering to the scrub brush 3 can be removed more efficiently.
By washing the scrub brush 3 with water, the scrub brush 3 is swollen with pure water. When the scrub brush 3 in this state is held in the pot body 31, the supply of alkaline gas (ammonia gas in this embodiment) is received from the alkaline liquid film 41, and the vicinity of the surface of the scrub brush 3 is quickly subjected to an alkaline aqueous solution. (In this embodiment, ammonia water is swollen). That is, alkaline gas and pure water in the scrub brush 3 are combined, and the pH in the vicinity of the surface of the scrub brush 3 rises quickly. As a result, the surface of the scrub brush 3 and the zeta potential of the foreign matter remaining there are both controlled negatively.

  In the experiment using the litmus paper by the inventor of the present application, the pH of the surface of the scrub brush 3 immediately after washing with water was about 7, but the pH of the surface rose to about 11 in about 10 seconds. Therefore, as described above, the scrub brush is used not only when the unprocessed wafer W is not loaded for a long time (for example, 30 minutes or more) but also when the unprocessed wafer W is continuously supplied. If 3 waits for at least about 10 seconds at the standby position, the effect of sufficiently increasing the pH of the surface of the scrub brush 3 can be obtained.

  When an unprocessed wafer W is processed after the standby period, the surface potential of the surface of the wafer W, the surface of the scrub brush 3 and the foreign matter attached thereto are all negative. Further, since ammonia water or ammonia hydrogen peroxide solution mixed liquid that is an alkaline liquid is supplied as a chemical solution to the surface of the wafer W, the zeta potential of the foreign matter on the surface of the wafer W also becomes negative. When scrub cleaning is performed in such a situation, the foreign matter on the surface of the wafer W is easily peeled off, and the peeled foreign matter is difficult to adhere to both the wafer W and the scrub brush 3. Further, even if the remaining foreign matter on the surface of the scrub brush 3 is peeled off from the scrub brush 3, such foreign matter is not easily reattached to the wafer W or the scrub brush 3. Of course, the accumulation of foreign matter on the scrub brush 3 is also suppressed. The foreign matter peeled off from the wafer W and the scrub brush 3 is washed away by the processing liquid (ammonia water or ammonia hydrogen peroxide solution mixture) and discharged out of the wafer W. In this way, it is possible to satisfactorily perform the cleaning process on the wafer W immediately after the standby period, and it is possible to perform an excellent scrub cleaning process on any wafer W.

In addition, since the alkaline liquid is not supplied to the scrub brush 3 but the alkaline gas volatilized from the alkaline liquid is supplied to the scrub brush 3, the consumption of the alkaline liquid is small. As a result, the scrub cleaning quality can be improved without significantly increasing the running cost.
FIG. 3 is a diagram showing the results of examining the relationship between pH and zeta potential for various substances that may exist in a semiconductor process. From this figure, it is generally considered that when the pH is 9 or more, the zeta potential can be surely negative, and a silicon wafer, which is a typical semiconductor wafer, and foreign matter on its surface can be repelled. .

FIG. 4 is a diagram showing the relationship between the concentration of aqueous ammonia as an example of the alkaline liquid and its pH. From this figure, it can be seen that even ammonia water with ammonia: water = 1: 1000 has a pH of about 10, and a sufficient effect can be obtained in controlling the zeta potential of the scrub brush and the foreign matter on its surface.
FIG. 5 is an illustrative sectional view showing another configuration example of the standby pot 5. 5, parts corresponding to the respective parts shown in FIG. 2 are given the same reference numerals as those in FIG.

  In this configuration example, a cylindrical (for example, cylindrical) dam member 44 surrounding the drainage port 43 is erected on the inner side of the bottom plate 42. An alkaline liquid storage part 45 for storing an alkaline liquid is formed outside the dam member 44 between the inner surface of the side wall 37 of the pot body 31. That is, the alkaline liquid storage part 45 is formed in an annular shape surrounding the drainage port 43. The side wall 37 is provided with an alkaline liquid port 40 for supplying an alkaline liquid to the alkaline liquid reservoir 45, and the alkaline liquid supply pipe 22 is coupled to the alkaline liquid port 40.

  A liquid receiving member 48 is disposed above the alkaline liquid reservoir 45. The liquid receiving member 48 is an annular plate-like body having an opening 49 in the central portion facing the lower surface of the scrub brush 3 at the standby position. The liquid receiving member 48 is disposed substantially horizontally below the cleaning liquid port 38 between the alkaline liquid reservoir 45 and the scrub brush 3 at the standby position.

  The liquid receiving member 48 covers substantially the entire area of the upper surface of the alkaline liquid storage part 45 in plan view. Thus, when pure water as the cleaning liquid is discharged toward the scrub brush 3 from the liquid discharge port 39 of the cleaning liquid port 38, the pure water is prevented or prevented from entering the alkaline liquid storage section 45. Thereby, it can suppress or prevent that the alkaline liquid stored in the alkaline liquid storage part 45 is diluted.

The cleaning liquid that flows down after being supplied to the scrubbing brush 3 is guided to the drainage port 43 disposed immediately below through the opening 49 formed in the liquid receiving member 48 and discharged.
On the other hand, the alkaline gas volatilized from the alkaline liquid stored in the alkaline liquid storage part 45 reaches the scrub brush housing space 34 above it through the opening 49 and is supplied to the scrub brush 3 at the standby position.

  The alkaline liquid port 40 is provided between the liquid receiving member 48 and the alkaline liquid reservoir 45 in the height direction. The alkaline liquid valve 24 interposed in the alkaline liquid supply pipe 22 connected to the alkaline liquid port 40 is always kept open during the operation period of the substrate processing apparatus by the control device 30 (see FIG. 1). . Thereby, the alkaline liquid is always supplied at a small flow rate from the alkaline liquid port 40 to the alkaline liquid reservoir 45 (so-called slow leak). Accordingly, the alkaline liquid stored in the alkaline liquid storage unit 45 overflows the weir member 44 and is discharged to the drain port 43. In this way, since the alkaline liquid in the alkaline liquid reservoir 45 can be replaced with a new liquid, dilution of the concentration due to volatilization of the alkaline gas can be suppressed, and the alkaline gas can be constantly generated.

A pure water supply pipe 46 that guides pure water from a pure water supply source is branchedly connected to the alkaline liquid supply pipe 22. A pure water valve that is controlled to open and close by the control device 30 is connected to the pure water supply pipe 46. 47 is interposed. The pure water valve 47 is opened for the purpose of replacing the ammonia water stored in the alkaline liquid storage unit 45 with pure water during maintenance or the like.
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form. For example, in the above-described embodiment, the alkaline liquid storage unit is always subjected to a slow leak of the alkaline liquid during the operation period of the substrate processing apparatus. However, the alkaline liquid storage unit is alkaline only when a standby period of a predetermined time or more occurs. It is good also as supplying the alkaline liquid to a liquid storage part.

In the above embodiment, the scrub brush 3 is washed with water in the standby pot 5, but this washing treatment is not necessarily required. However, it is preferable to perform a water washing process in order to reduce foreign matter on the surface of the scrub brush 3 as much as possible and prevent the scrub brush 3 from drying during the standby period.
In the above-described embodiment, the alkaline gas is generated by volatilization from the alkaline liquid. However, the alkaline gas from the alkaline gas supply source (gas tank or the like) may be supplied to the scrub brush 3 at the standby position. .

  Also, there is no problem when using an alkaline liquid having sufficient volatility such as ammonia water, but when using an alkaline liquid with insufficient volatility, the effect of controlling the zeta potential of a scrub brush or the like is sufficient. It is conceivable that it cannot be obtained. In such a case, for example, the standby pot 5 may be provided with a heating mechanism (such as a heater) for heating the alkaline liquid in the alkaline liquid storage unit to promote vaporization of the alkaline liquid.

In the above-described embodiment, ammonia water is used as the alkaline liquid introduced from the alkaline liquid port 40. However, the present invention is not limited to this, but NH ₄ +, RNH ₃ +, R ₂ NH ₂ +, R _{3 are used.} An aqueous solution containing at least one ion of NH +, R ₄ N + may be used.
In the above-described embodiment, pure water is used as the cleaning liquid discharged from the liquid discharge port 39. However, the present invention is not limited to this. Of the reduced water (hydrogen water) and electrolytic ion water (particularly alkaline ion water), Any one of the above can be used. In particular, when reducing water (hydrogen water) or alkaline ionized water is used as the cleaning liquid, the pH of the surface of the scrub brush 3 can be further increased, and the zeta of the foreign matter remaining slightly on the surface of the scrub brush 3. The electric potential can be controlled more negatively.

Further, in the above-described embodiment, ammonia water or a mixed solution of ammonia hydrogen peroxide solution is used as the processing liquid supplied from the processing liquid nozzle 2 to the wafer W. However, the present invention is not limited to this, and NH ₄ +, RNH _It may be an aqueous solution containing at least one ion of ₃ +, R ₂ NH ₂ +, R ₃ NH +, and R ₄ N +.
In the above-described embodiment, the substrate processing apparatus that scrubs with the scrub brush 3 while holding and rotating the wafer W is taken as an example, but a scrub brush (for example, a roll shape) is held while holding the wafer in a non-rotating state. The present invention can also be applied to a substrate processing apparatus configured to scrub.

Furthermore, in the above embodiment, an apparatus for processing a semiconductor wafer is taken as an example. However, the present invention is similarly applied to an apparatus for processing other types of substrates such as a glass substrate for a liquid crystal display device. can do.
In addition, various design changes can be made within the scope of matters described in the claims.

1 is a schematic perspective view for explaining a basic configuration of a substrate processing apparatus according to an embodiment of the present invention. It is an illustration sectional view showing the example of composition of a standby pot. It is a figure which shows the result of having investigated the relationship between pH and zeta potential about the various substances which may exist in a semiconductor process. It is a figure which shows the relationship between the density | concentration of ammonia water as an example of alkaline liquid, and its pH. It is an illustration sectional view showing other examples of composition of a waiting pot.

Explanation of symbols

1 Spin chuck (substrate holding and rotating mechanism)
2 treatment liquid nozzle 3 scrub brush 4 brush moving mechanism 5 standby pot 6 rotation base 7 rotation shaft 8 chuck rotation drive mechanism 9 chuck pin 11 chemical liquid valve 12 pure water valve 15 swing arm 16 support shaft 17 swing drive mechanism 18 lift drive Mechanism 20 Brush rotation drive mechanism 21 Cleaning liquid supply pipe 22 Alkaline liquid supply pipe 23 Cleaning liquid valve 24 Alkaline liquid valve 25 Drain pipe 30 Controller 31 Pot body 32 Alkaline liquid storage part 33 Brush inlet 34 Scrub brush storage space 35 Drainage part 36 Opening 37 Side wall 38 Cleaning liquid port 39 Liquid discharge port (cleaning liquid nozzle)
40 Alkaline liquid port 41 Alkaline liquid film 42 Bottom plate 43 Drainage port 44 Weir member 45 Alkaline liquid storage portion 46 Pure water supply pipe 47 Pure water valve 48 Liquid receiving member 49 Opening W Semiconductor wafer

Claims (9)

A substrate holding mechanism for holding the substrate;
A scrub brush for scrubbing the surface of the substrate held by the substrate holding mechanism to remove foreign matter on the substrate surface;
A substrate processing apparatus, comprising: an alkaline gas supply mechanism that supplies an alkaline gas to a surface of the scrub brush during standby when the scrub brush is not scrubbing the substrate.   The substrate processing apparatus according to claim 1, further comprising a processing liquid supply mechanism that supplies a processing liquid to a surface of the substrate when the substrate is scrubbed with the scrub brush. A brush moving mechanism for moving the scrub brush between a processing position for scrubbing the substrate surface and a standby position retracted from the processing position;
The substrate processing apparatus according to claim 1, wherein the alkaline gas supply mechanism supplies an alkaline gas to the scrub brush at the standby position.   The substrate processing apparatus according to claim 3, further comprising a cleaning liquid supply mechanism that supplies a cleaning liquid to the scrub brush in the standby position.   5. The substrate processing apparatus according to claim 3, wherein the alkaline gas supply mechanism includes an alkaline liquid storage unit that stores a volatile alkaline liquid that volatilizes and generates an alkaline gas below the standby position.   The substrate processing apparatus according to claim 5, further comprising a liquid receiving member that is disposed above the alkaline liquid storage part and suppresses or prevents mixing of other liquids into the alkaline liquid storage part. A scrubbing step of scrubbing the surface of the substrate with a scrub brush to remove foreign matter on the substrate surface;
An alkaline gas supplying step of supplying an alkaline gas to the surface of the scrub brush and negatively controlling the zeta potential of the scrub brush and the foreign matter attached to the scrub brush during standby when the scrub brush is not scrubbing the substrate; A substrate processing method comprising:   8. The substrate processing method according to claim 7, further comprising a processing liquid supply step of supplying a processing liquid to the surface of the substrate in parallel with the scrubbing step. The substrate processing method according to claim 7, further comprising a cleaning liquid supply step of supplying a cleaning liquid to the scrub brush during the standby.

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