JP2006032637A - Substrate washing device and substrate washing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate washing device and a method for carrying out chemical treatment, washing treatment and drying treatment in this order while rotating a substrate, and for suppressing the generation of mist by setting a fixed period from a washing treatment process to a drying treatment process, and controlling the rotating speed of the substrate in this period. <P>SOLUTION: In this substrate washing device and a method, an acceleration process is set from the end of the washing treatment process to the start of the drying treatment process, and the rotating speed of the substrate is gradually changed from a low speed to a high speed in this process. The number of rotations of the substrate is smoothly accelerated, and finally the rotating speed of the substrate is increased to a speed suitable for the drying treatment process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a substrate cleaning apparatus and a substrate cleaning method, and in particular, rotation control when shifting to cleaning processing → drying processing in substrate cleaning in which cleaning is performed in the order of chemical processing → cleaning processing → drying processing while rotating the substrate. The present invention relates to a substrate cleaning apparatus and a substrate cleaning method that are optimized.

In the semiconductor device manufacturing process, impurities attached to the substrate are removed as necessary before and after each process.
For example, there is a technique in which a chemical solution and a cleaning solution are supplied toward the center of a rotating semiconductor substrate, and the chemical solution and the cleaning solution are spread on the substrate by using centrifugal force to perform cleaning. Such a cleaning apparatus includes a stage for horizontally fixing a substrate as an object to be cleaned, a rotation mechanism capable of rotating at an arbitrary speed of 10 to 3000 rotations / min with the center as a rotation axis, and a substrate fixed to the stage. It is comprised from the nozzle which supplies a chemical | medical solution and a washing | cleaning liquid on it. The substrate cleaning step is composed of three stages: a first chemical processing, a second cleaning processing, and a third drying processing. The chemical liquid and the cleaning liquid supplied from the nozzle spread on the rotating substrate, and perform the chemical processing and cleaning processing of the substrate. The supplied chemical solution and cleaning solution flow on the substrate and are collected by a collection chamber provided along the outer periphery of the stage. When the cleaning with the cleaning liquid is completed, the supply of the cleaning liquid is stopped, the rotation speed of the substrate is increased, and the cleaning liquid remaining on the substrate is shaken off and dried.

  In the final drying process, a vortex airflow is generated due to high-speed rotation, and cleaning liquid mist is scattered in the case where the stage is installed. There is a problem that the mist is scattered upward and effective exhaust cannot be performed from the exhaust port. Since the mist contains a large amount of impurities, it adheres to the substrate and becomes particles that are very small in particle size after the substrate is dried, causing a product defect. On the other hand, the technique which provides a suction port in the case side surface and discharges mist is proposed (for example, patent document 1).

According to this technology, the exhaust equipment is enhanced to remove the generated mist. However, due to the increase in cost accompanying the enhancement of the equipment, an inexpensive system cannot be realized. In addition, since it is assumed that the exhaust equipment can be maintained normally, when the trouble that cannot be maintained is encountered, the above-mentioned problems are immediately reoccurred. Therefore, it is important to reduce the occurrence of mist itself. From this point of view, several techniques have been proposed (for example, Patent Documents 2 and 3).
JP 2000-153209 A JP-A-8-195375 Japanese Utility Model Publication No. 58-170831

  However, since the amount of mist generated increases with the increase in size of the substrate, there is a limit to the removal of mist only by the above technique. In addition, as the device is miniaturized, it is necessary to spread the cleaning solution sufficiently between fine patterns. Therefore, the rotation speed during the cleaning process is conventionally about 1000 rotations / minute up to about 300 rotations / minute. Must be suppressed.

FIG. 7 is a chart showing the elapsed time and rotation speed of the substrate cleaning process for a large substrate. The treatment process is divided into three stages: a chemical treatment process, a washing treatment process, and a drying treatment process.
As shown in FIG. 7, the substrate rotation speed is increased from 300 rotations / minute to 1500 rotations / minute in about 2 seconds from the end of the cleaning process to the start of the drying process. With the completion of the cleaning process, the supply of the cleaning liquid to the substrate is stopped, but at this point, a large amount of the cleaning liquid remains on the substrate surface. For this reason, when the number of rotations of the substrate is increased at once, the cleaning liquid remaining on the substrate is shaken off by the centrifugal force at a stretch and collides violently with the wall surface of the recovery chamber, thereby promoting the generation of mist. This phenomenon becomes more prominent as the diameter of the substrate increases, the rotation speed in the cleaning process decreases as the substrate becomes finer, and the difference from the rotation speed in the drying process increases.

  The present invention has been made on the basis of recognition of such problems, the purpose of which is from a cleaning process step in a substrate cleaning apparatus that performs processing in the order of chemical processing → cleaning processing → drying processing while rotating the substrate. It is an object of the present invention to provide a substrate cleaning apparatus and a substrate cleaning method in which a certain period is provided between the drying process steps, and generation of mist is suppressed by controlling the rotation speed of the substrate during this period.

  In the substrate cleaning apparatus of the present invention, an acceleration process is provided after the cleaning process is completed and before the drying process is started, and the rotation speed of the substrate is changed stepwise from low to high in this process. The rotational speed of the substrate is gradually accelerated, and finally the rotational speed of the substrate is increased to a speed suitable for the drying process.

That is, according to the first aspect of the present invention,
A substrate rotation mechanism that keeps the substrate horizontal and rotates around its center;
A liquid supply mechanism for supplying a chemical solution and a cleaning solution to the surface of the substrate through a nozzle provided on the substrate;
A controller that controls the substrate rotation mechanism and the liquid supply mechanism;
A collection chamber that is provided along the outer periphery of the substrate rotation mechanism and collects the chemical solution and the cleaning solution flowing from the substrate;
With
The controller is
The period for supplying the chemical solution from the nozzle by the liquid supply mechanism is controlled so that the substrate rotation mechanism rotates at a first rotation speed,
During the period of supplying the cleaning liquid from the nozzle by the liquid supply mechanism, the substrate rotation mechanism is controlled to rotate at a second rotation speed,
After the supply of the cleaning liquid from the nozzle is stopped by the liquid supply mechanism, the rotation mechanism is accelerated stepwise from the second rotation speed to a third rotation speed enough to shake off the cleaning liquid remaining on the surface of the substrate. A substrate cleaning apparatus is provided that is controlled to rotate while rotating.

Here, a buffer member that absorbs the impact of the colliding water may be provided on the surface of the recovery chamber with respect to the rotation mechanism.
Moreover, the said buffer member shall be comprised with the water-repellent material.
Moreover, the said buffer member shall be mesh shape.
Furthermore, a taper may be provided at the tip of the mesh.

On the other hand, according to the second aspect of the present invention, in the substrate cleaning method, the substrate is cleaned by supplying the chemical solution and the cleaning solution from the nozzle to the surface of the substrate while keeping the substrate horizontal and rotating around the center. There,
A chemical treatment process for supplying a chemical while rotating the substrate at a first rotational speed;
A cleaning treatment step of supplying a cleaning liquid while rotating the substrate at a second rotation speed;
A drying process for drying the cleaning liquid on the substrate while rotating the substrate at a third rotation speed greater than the second rotation speed;
An acceleration step of accelerating the rotation speed of the substrate stepwise from the second rotation speed to the third rotation speed between the cleaning treatment step and the drying treatment step;
A substrate cleaning method is provided.

  Here, when the diameter of the substrate is 300 millimeters, the second rotation speed may be about 300 rotations / minute.

According to the present invention, in the substrate cleaning method for performing processing in the order of chemical treatment → water washing treatment → drying treatment while rotating the substrate, an acceleration step is provided between the cleaning treatment step and the drying treatment step, and the substrate rotation speed is achieved. Accelerate slowly. For this reason, since the cleaning liquid remaining on the surface of the substrate is moved by a gentle centrifugal force when the cleaning process is completed, it does not collide violently with the wall surface of the recovery chamber, and the generation of mist due to the collision can be suppressed. Furthermore, in the substrate cleaning apparatus, the impact of collision is suppressed by the buffer member installed on the wall surface of the recovery chamber, so that the effect of suppressing mist generation is enhanced.
In this way, the generation of mist during substrate cleaning can be suppressed, so that the yield of semiconductor products can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an outline of a substrate cleaning apparatus that cleans a substrate using centrifugal force due to rotation.
That is, the substrate cleaning apparatus of the present embodiment supplies the chemical solution and the cleaning liquid through the rotary stage 101, the substrate rotating mechanism 102 that controls the rotation, the nozzle 103 provided above the rotary stage 101, and the nozzle. The liquid supply mechanism 104 and the controller 105 that controls the substrate rotation mechanism 102 and the liquid supply mechanism 104 are configured.

The substrate W that is the object to be cleaned is fixed to the rotary stage 101. The rotation stage 101 is attached to a rotation shaft 106 and is controlled to rotate by the substrate rotation mechanism 102. The rotation speed is adjusted to an arbitrary speed of 10 to 3000 rpm. A fixing pin 107 is installed on the rotary stage 101 and is fixed so that the substrate W is not displaced by a rotational movement. The nozzle 103 is controlled by the liquid supply mechanism 104 to supply the chemical liquid and the cleaning liquid.
The control unit 105 performs control related to the rotation speed for the substrate rotation mechanism 102 and the supply of the chemical liquid and the cleaning liquid to the liquid supply mechanism 104.
Substrate cleaning is performed by utilizing the fact that a liquid 108 such as a chemical solution and pure water is supplied from a nozzle 103 onto a rotating substrate and spreads toward the outer periphery of the substrate by centrifugal force. The supplied liquid flows on the substrate and is collected by a collection chamber (not shown).

FIG. 2 is a chart showing the elapsed time and rotation speed of the substrate cleaning process according to the embodiment of the present invention.
The treatment process is divided into four stages: a chemical treatment process, a cleaning treatment process, an acceleration process, and a drying treatment process.

  As shown in FIG. 2, the acceleration process provided after the completion of the cleaning process is approximately 25 seconds. In this step, the rotation speed of the substrate is increased stepwise from 300 rotations / minute to 1500 rotations / minute. Compared with FIG. 7, it is accelerated gently over a long time, so that the cleaning liquid remaining on the substrate surface at the end of the cleaning process moves to the outer periphery of the substrate by a gentle centrifugal force. Thus, the impact when the cleaning liquid that has reached the outer peripheral portion of the substrate collides with the collection chamber is much smaller than that in the case of FIG. Therefore, the generation of mist due to the impact of the collision is remarkably suppressed.

FIG. 3 is a schematic diagram showing a state of the outer peripheral portion of the substrate in the acceleration process. The same components as those in FIG. 1 are denoted by the same reference numerals.
In FIG. 3, the rotation stage 101 on which the substrate W is fixed by the fixing pins 107 is rotated by a substrate rotation mechanism (not shown). The collection chamber 301 installed so as to cover the back surface and the side surface of the rotary stage 101 is provided with drainage and an exhaust port 302 to suck the cleaning liquid shaken off from the substrate and the generated mist 303. Now, the cleaning liquid 108 that has moved from the center of the substrate is gathered at the end of the substrate W, and these are gradually shaken off and collected by the collection chamber 301 and flow to the drainage and exhaust ports.

4 is an enlarged cross-sectional view of a part of the collection chamber 301 shown in FIG. The same components as those in FIGS. 1 and 3 are denoted by the same reference numerals.
In FIG. 4, a buffer member 402 is fixed to the inner wall of the collection chamber 301 by a fixing pin 401. Although only a part of the buffer member 402 is shown in FIG. 4, the buffer member 402 is installed so as to go around the inner circumference of the collection chamber 304. This affixing position is a position where a water droplet shaken off when the substrate rotates hits. Since the buffer member 402 is made of a water repellent material such as Teflon (registered trademark) resin, for example, the shock absorbing member 402 absorbs the impact of the colliding water droplet and promptly moves to the recovery chamber 301 without holding the water droplet. Lead.

  FIG. 5 is an enlarged cross-sectional view of the surface of the buffer member shown in FIG. If a material that is hydrophilic and easily wetted with water is used for the buffer member 402, water droplets remain on the buffer member for a long time, which may cause mist generation due to wind pressure at high speed rotation. For this reason, in order to improve the water-repellent effect, the surface of the buffer member 402 has, for example, a mesh shape, and the tip has a tapered shape 501. By adopting the tapered shape 501, the contact area when the water droplet collides is reduced, and the effect of reducing the impact is improved. By adopting such materials and shapes, it is possible to eliminate the cause of mist generation and to prevent the generation of bacteria due to water droplets remaining for a long time.

  FIG. 6 is an enlarged cross-sectional view of the surface of a buffer member having a cross-sectional shape different from that of FIG. In addition to the tapered shape 601 similar to that of FIG. 5, a groove portion 602 for guiding the flow of water droplets is formed on the side surface. If such a shape is employ | adopted, the water-repellent effect of a buffer member will further improve.

  5 and 6 may be a projection having only tapered shapes 501 and 601. By adopting such a shape, the water repellent effect is further enhanced.

As described above, by employing the substrate cleaning apparatus and the substrate cleaning method of the present invention, it is possible to suppress mist generated during substrate cleaning and improve yield reduction due to particles.
The present invention can be applied to substrates of any size, but has a great effect especially on large substrates having a diameter of 300 mm or more. Even a small substrate is particularly effective when there is a large difference in the number of rotations of the substrate between the cleaning process and the drying process, for example, during microfabrication.

  The control unit 105 may include a program for causing the substrate rotation mechanism 102 and the liquid supply mechanism 104 to execute a series of operations with certainty.

It is a schematic diagram showing the outline | summary of the board | substrate cleaning apparatus which cleans a board | substrate using the centrifugal force by rotation. It is the graph showing the elapsed time and rotation speed of the washing | cleaning process of the board | substrate concerning embodiment of this invention. It is a schematic diagram showing the mode of the outer peripheral part of the board | substrate in an acceleration process. FIG. 4 is an enlarged cross-sectional view of a part of a collection chamber 301 shown in FIG. It is sectional drawing to which the surface of the buffer member represented in FIG. 4 was expanded. It is sectional drawing to which the surface of the buffer member with a different cross-sectional shape from FIG. 5 was expanded. It is the graph showing the elapsed time and rotation speed of the board | substrate washing | cleaning process with respect to a large sized board | substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Rotation stage 102 Substrate rotation mechanism 103 Nozzle 104 Liquid supply mechanism 105 Control unit 106 Rotating shaft 107, 401 Fixed pin 108 Cleaning liquid 301, 304 Recovery chamber 302 Exhaust port 303 Mist 402 Buffer member 501, 601 Taper shape 602 Groove W Substrate

Claims (6)

A substrate rotation mechanism that keeps the substrate horizontal and rotates around its center;
A liquid supply mechanism for supplying a chemical solution and a cleaning solution to the surface of the substrate through a nozzle provided on the substrate;
A controller that controls the substrate rotation mechanism and the liquid supply mechanism;
A collection chamber that is provided along the outer periphery of the substrate rotation mechanism and collects the chemical solution and the cleaning solution flowing from the substrate;
With
The controller is
The period for supplying the chemical solution from the nozzle by the liquid supply mechanism is controlled so that the substrate rotation mechanism rotates at a first rotation speed,
During the period of supplying the cleaning liquid from the nozzle by the liquid supply mechanism, the substrate rotation mechanism is controlled to rotate at a second rotation speed,
After the supply of the cleaning liquid from the nozzle is stopped by the liquid supply mechanism, the rotation mechanism is accelerated stepwise from the second rotation speed to a third rotation speed enough to shake off the cleaning liquid remaining on the surface of the substrate. A substrate cleaning apparatus, wherein the substrate cleaning apparatus is controlled to rotate while rotating.   The substrate cleaning apparatus according to claim 1, wherein a buffer member that absorbs the impact of the impinging water is provided on a surface of the recovery chamber with respect to the rotation mechanism.   3. The substrate cleaning apparatus according to claim 2, wherein the buffer member is made of a water-repellent material.   4. The substrate cleaning apparatus according to claim 3, wherein the buffer member has a mesh shape, or has a mesh shape and is provided with a taper at a tip thereof. A substrate cleaning method for cleaning a substrate by supplying a chemical solution and a cleaning solution from a nozzle to the surface of the substrate while keeping the substrate horizontal and rotating about its center as an axis,
A chemical treatment process for supplying a chemical while rotating the substrate at a first rotational speed;
A cleaning treatment step of supplying a cleaning liquid while rotating the substrate at a second rotation speed;
A drying process for drying the cleaning liquid on the substrate while rotating the substrate at a third rotation speed greater than the second rotation speed;
An acceleration step of accelerating the rotation speed of the substrate stepwise from the second rotation speed to the third rotation speed between the cleaning treatment step and the drying treatment step;
A substrate cleaning method comprising: 6. The substrate cleaning method according to claim 5, wherein when the diameter of the substrate is 300 millimeters, the second rotation speed is about 300 rotations / minute.