JP2006196636A - Wafer cleaning apparatus and cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To clean a wafer stably without impeding the rotation of the wafer upon cleaning the wafer. <P>SOLUTION: In a forward direction movement range where a movement direction of a wafer surface following the rotation of a wafer 14 is the same direction as a movement direction of a cleaning brush surface in accordance with the rotation of a cleaning blush 13, the cleaning blush 13 faces the wafer surface from the center of the wafer surface to the periphery of the wafer surface. In an opposite direction movement range of the wafer surface where the movement direction of the wafer surface following the rotation of the wafer 14 is in an opposite direction to that of the surface of the cleaning blush in accordance with the rotation of the cleaning blush 13, the size of the cleaning blush 13 facing the wafer surface is 0 to 95% of a radius (r) of the wafer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wafer cleaning apparatus and a cleaning method, and more particularly to a wafer cleaning apparatus and a cleaning method for cleaning a wafer while holding the wafer surface in a vertical direction and rotating the wafer.

  In manufacturing a semiconductor device or the like, it is necessary to maintain high cleanliness of the wafer surface on which the device is formed. For this reason, in the semiconductor device manufacturing process, the wafer is cleaned whenever necessary. Conventionally, a horizontal cleaning system in which a wafer is rotated in a horizontal plane, a cleaning liquid is supplied from a cleaning nozzle, and a cleaning brush is pressed against the wafer surface to perform cleaning has been mainstream (for example, Patent Document 1). Patent Document 2 describes a vertical cleaning method in which a cleaning brush is pressed against a wafer surface while rotating the wafer surface in a substantially vertical plane.

  FIGS. 3A and 3B respectively show a state of cleaning by the wafer cleaning apparatus (brush scrub apparatus) described in Patent Document 2 in a front view and a side view of the wafer. The wafer cleaning apparatus holds a wafer 24 with the wafer surface substantially vertical, a wafer holding jig 22 for rotating the wafer 24, a cleaning nozzle 21 for supplying a cleaning liquid 25 such as pure water or chemicals to the wafer surface, a brush A cylindrical cleaning brush 23 that rotates around the rotation axis and is pressed against the wafer surface to clean the wafer surface is provided.

  In the wafer cleaning apparatus, the wafer is rotated in the arrow “A” direction while supplying the cleaning liquid 25 to the wafer surface, and at the same time, the cleaning brush 23 is rotated at a high speed in the arrow “B” direction while being pressed against the wafer surface. Then, the foreign matter adhering to the wafer surface is removed. The center of the rotation axis direction of the cleaning brush 23 is arranged somewhat eccentric from the center of the wafer surface. At the wafer edge where the wafer surface moves at a high speed as the wafer 24 rotates, the cleaning brush 23 is arranged. The movement direction of the cleaning brush surface accompanying the rotation of the wafer 24 and the movement direction of the wafer surface accompanying the rotation of the wafer 24 are opposite to each other. In Patent Document 2, by adopting a vertical wafer cleaning system, foreign matter on the wafer surface removed by the cleaning brush 23 is prevented from flowing around the back surface of the wafer 24 and contaminating the back surface.

Japanese Patent Laid-Open No. 11-238713 (FIG. 1) JP-A-6-326066 (FIGS. 1 and 6)

  In general, the cleaning brush is formed of a soft material, and has a large variation in dimensional accuracy at the initial stage of manufacture. In addition, this variation further increases due to distortion caused when the cleaning brush is incorporated into the wafer cleaning apparatus and changes over time after the cleaning process, and it is difficult to keep the brush in an ideal cylindrical shape. For example, if subtle irregularities occur on the surface of the cleaning brush, the amount of pressing against the wafer cannot be kept constant over the entire circumference of the brush.

  The frictional force applied to the wafer surface by the cleaning brush is proportional to the number of brush rotations and the amount of brush pressing. Here, the total amount of pressing in the forward movement range of the wafer surface where the movement direction of the wafer surface is the same as the movement direction of the cleaning brush surface, and the movement direction of the wafer surface is opposite to the movement direction of the cleaning brush surface. In relation to the total amount of pressing in the reverse movement range of a certain wafer surface, if the latter sum increases, the rotation of the wafer is hindered, causing problems such as a decrease in rotation and rotation stoppage.

  In addition, if the rotation speed of the wafer varies due to lot variation during cleaning brush molding, variation in assembly of the cleaning brush, change in cleaning brush over time, variation in parallel adjustment of the cleaning brush, etc., wafer cleaning processing is performed stably. There is also a problem that it is not broken.

  In view of the above, the present invention has improved a wafer cleaning apparatus that performs vertical cleaning of a wafer, and prevents unstable rotation of the wafer such as inhibition of rotation of the wafer, reduction in rotation, and rotation stop, thereby It is an object to provide a wafer cleaning apparatus capable of performing stable wafer cleaning even when there is lot variation at the time of molding, variation in assembly of the cleaning brush, change in the cleaning brush with time, and variation in parallel adjustment of the cleaning brush. To do.

In order to achieve the above object, a wafer cleaning apparatus of the present invention cleans a wafer surface that is pressed against the wafer surface while rotating around a brush rotation axis while rotating the wafer surface while holding the wafer vertically. In a wafer cleaning apparatus comprising a cleaning brush
In the forward movement range of the wafer surface where the movement direction of the wafer surface accompanying the rotation of the wafer is the same as the movement direction of the cleaning brush surface accompanying the rotation of the cleaning brush, the cleaning brush moves from the wafer surface center to the periphery of the wafer surface. In the reverse movement range of the wafer surface where the wafer surface is opposed to the wafer surface and the movement direction of the wafer surface accompanying the rotation of the wafer is opposite to the movement direction of the cleaning brush surface accompanying the rotation of the cleaning brush, It is characterized by not facing the surface or facing the wafer surface in a part from the center of the wafer surface to the periphery of the wafer surface.

The wafer cleaning method of the present invention uses a wafer roller that rotates while holding the wafer with the wafer surface vertical, and a cleaning brush that is pressed against the wafer surface while rotating about the brush rotation axis to clean the wafer surface. In the wafer cleaning method for cleaning the wafer,
In the forward movement range of the wafer surface where the movement direction of the wafer surface accompanying the rotation of the wafer is the same as the movement direction of the cleaning brush surface accompanying the rotation of the cleaning brush, the cleaning brush moves from the wafer surface center to the periphery of the wafer surface. In the reverse movement range of the wafer surface where the wafer surface is opposed to the wafer surface and the movement direction of the wafer surface accompanying the rotation of the wafer is opposite to the movement direction of the cleaning brush surface accompanying the rotation of the cleaning brush, The cleaning brush is positioned so as not to face the surface or to face the wafer surface in a part from the center of the wafer surface to the periphery of the wafer surface.

  In the wafer cleaning apparatus and the cleaning method of the present invention, the cleaning brush faces the wafer surface in the entire range of forward movement of the wafer surface, and the cleaning brush does not face or faces the wafer surface in the backward movement range of the wafer surface. By reducing the size, the range in which the rotation of the cleaning brush hinders the rotation of the wafer can be reduced, and the rotation of the wafer as a whole is not obstructed. Therefore, the wafer rotates stably, and as a result, stable wafer cleaning is possible. become.

  In a preferred aspect of the wafer cleaning apparatus of the present invention, the cleaning brush is disposed on both the front and back wafer surfaces. By adopting this configuration, the fluctuation of the wafer surface is reduced and more stable wafer cleaning is possible.

Moreover, in the cleaning apparatus of the present invention, it is preferable to select the facing size of the cleaning brush in the reverse movement range of the wafer surface according to the type of cleaning brush. Here, assuming that the radius of the wafer surface is r, the cleaning brush has the following dimension L with respect to the wafer surface in the backward movement range of the wafer surface:
0 ≦ L ≦ 0.95r
It is preferable to oppose the wafer surface within the range.

  Hereinafter, a wafer cleaning apparatus according to an embodiment of the present invention will be described with reference to the drawings. The entire wafer cleaning apparatus is disposed in the vertical cleaning tank 10 and includes a cleaning nozzle 11, a wafer rotating roller 12, and a cleaning brush 13. The wafer 14 to be cleaned is supported on the three wafer rotating rollers 12 at the wafer edge. The wafer 14 receives a rotational force by a frictional force with the rotating wafer rotating roller 12 and rotates in the direction of the arrow “A1” while being sandwiched between the pair of cleaning brushes 13.

  The cleaning nozzle 11 drops a cleaning liquid 15 such as pure water or chemicals onto both the front and back wafer surfaces. The pair of cleaning brushes 13 is rotated at high speed in the direction of the arrow “B1” while being pressed against the wafer surface, and cleans the wafer surface on which the cleaning liquid 15 is dropped. The cleaning brush 13 has a cylindrical shape and has an axial length shorter than the diameter of the wafer surface and longer than the radius. The cleaning brush 13 is opposed to the wafer surface over the entire range of forward movement of the wafer surface where the moving direction of the wafer surface is the same as the moving direction of the cleaning brush surface, and the moving direction of the wafer surface is the moving direction of the cleaning brush surface. In the reverse movement range of the wafer surface which is the reverse direction, the wafer surface is disposed so as to face only a part of the wafer surface.

  FIG. 2 is a plan view of the wafer cleaning apparatus of the above embodiment as viewed from above, and is shown for explaining the relative position of the cleaning brush 13 to the wafer surface. In the present embodiment, the cleaning brush 13 is a brush whose change in pressing amount is about 1.5 mm, which is generally used for cleaning a semiconductor wafer. As shown in the figure, when the radius of the wafer is r, the length of the cleaning brush 13 facing the wafer surface in the forward movement range of the wafer surface is r, and the cleaning brush 13 is in the backward movement range of the wafer surface. The length L facing the surface is L = r / 4. By adopting such a value, the cleaning brush 13 can clean the wafer while reducing the degree to which the rotation of the cleaning brush 13 hinders the rotation of the wafer 14.

  The position where the cleaning brush faces the wafer surface is determined as follows. In the forward movement range of the wafer surface, the cleaning brush allows the entire surface of the wafer surface to be cleaned with the effective portion of the brush facing the entire area in the wafer radial direction. In the reverse movement range of the wafer surface, an effective brush length is made to face the wafer surface so that the wafer can be cleaned within a range that does not hinder the rotation of the wafer.

  When the change in the pressing amount of the cleaning brush is extremely small, for example, 10 μm or less, the rotation of the wafer is reduced by setting the brush length in the reverse movement range to 99.5% or less of the brush length in the forward movement range. It can be washed without obstruction. On the other hand, the change in the pressing amount of the cleaning brush is extremely large. When the cleaning brush is 13 mm or more, the rotation of the brush is necessary unless the brush length in the reverse movement range is 0.05% or less of the brush length in the forward movement range. May be disturbed. When the change in the pressing amount is larger, the brush length in the reverse movement range is further shortened. As described above, the brush length in the backward movement range depends on the type of the cleaning brush, and is 0% to 99.5% of the brush length in the forward movement range. The cleaning device preferably has a position control device for controlling the axial position of the cleaning brush in order to cope with various cleaning brush materials and to cope with the aging of the cleaning brush.

  When using a general cleaning brush with a change in pressing amount of about 1.5 mm (1.5 ± 1 mm), the brush length in the reverse direction movement range is about 40% of the brush length in the forward direction movement range. By doing so, good cleaning is possible without hindering the rotation of the wafer. Here, in consideration of the change over time of the cleaning brush and other margins, the brush length in the backward movement range is set to 25% ± 10% of the brush length in the forward movement range. In this way, most of the cleaning brushes are arranged by decentering the cleaning brush in the direction of the forward movement range from the center of the wafer to the extent that it can sufficiently absorb the slight change in the amount of pressing between the cleaning brush and the wafer. This part rotates in the same direction as the moving direction of the wafer. Due to the construction, the cleaning brush positively assists the wafer rotation operation simultaneously with the brushing.

  As described above, the present invention has been described based on the preferred embodiments. However, the wafer cleaning apparatus and the cleaning method of the present invention are not limited to the configurations of the above-described embodiments, and various configurations are possible from the configurations of the above-described embodiments. Configurations modified and changed are also included in the scope of the present invention. In addition, each configuration described as a preferred aspect of the present invention or each configuration described in the embodiment is preferably used together with the essential configuration of the present invention, but about a configuration that exhibits a beneficial effect even when used alone. However, it is not always necessary to use all the configurations described as the essential configurations of the present invention.

  The wafer cleaning apparatus and the cleaning method of the present invention can be used for wafer cleaning that is performed at any time in a semiconductor device manufacturing process or the like.

(A) And (b) is the side view and front view of a wafer cleaning apparatus which concern on one Embodiment of this invention, respectively. The top view of the wafer cleaning apparatus of FIG. (A) And (b) is the figure which looked at the wafer from the front direction and the side direction for showing the conventional wafer cleaning apparatus, respectively.

Explanation of symbols

10: Vertical cleaning tank 11: Cleaning nozzle 12: Wafer rotating roller 13: Cleaning brush 14: Wafer 15: Cleaning liquid 21: Cleaning nozzle 22: Wafer holding jig 23: Cleaning brush 24: Wafer 25: Cleaning liquid

Claims (4)

In a wafer cleaning apparatus comprising a wafer roller that rotates while holding the wafer with the wafer surface vertical, and a cleaning brush that rotates around the rotation axis of the brush and is pressed against the wafer surface to clean the wafer surface.
In the forward movement range of the wafer surface where the movement direction of the wafer surface accompanying the rotation of the wafer is the same as the movement direction of the cleaning brush surface accompanying the rotation of the cleaning brush, the cleaning brush moves from the wafer surface center to the periphery of the wafer surface. In the reverse movement range of the wafer surface where the wafer surface is opposed to the wafer surface and the movement direction of the wafer surface accompanying the rotation of the wafer is opposite to the movement direction of the cleaning brush surface accompanying the rotation of the cleaning brush, A wafer cleaning apparatus characterized by not facing the surface or facing the wafer surface at a part from the center of the wafer surface to the periphery of the wafer surface.   The wafer cleaning apparatus according to claim 1, wherein the cleaning brush is disposed on both the front and back wafer surfaces. When the radius of the wafer surface is r, the cleaning brush has the following dimension L with respect to the wafer surface in the reverse movement range of the wafer surface:
0 ≦ L ≦ 0.95r
The wafer cleaning apparatus according to claim 1, wherein the wafer cleaning apparatus is opposed to the wafer surface within a range. In a wafer cleaning method for cleaning a wafer using a wafer roller that rotates while holding the wafer with the wafer surface vertical, and a cleaning brush that rotates around the rotation axis of the brush and is pressed against the wafer surface to clean the wafer surface,
In the forward movement range of the wafer surface where the movement direction of the wafer surface accompanying the rotation of the wafer is the same as the movement direction of the cleaning brush surface accompanying the rotation of the cleaning brush, the cleaning brush moves from the wafer surface center to the periphery of the wafer surface. In the reverse movement range of the wafer surface where the wafer surface is opposed to the wafer surface and the movement direction of the wafer surface accompanying the rotation of the wafer is opposite to the movement direction of the cleaning brush surface accompanying the rotation of the cleaning brush, A wafer cleaning method, wherein the cleaning brush is positioned so as not to face the surface or to face the wafer surface in a part from the center of the wafer surface to the periphery of the wafer surface.

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