JPH118212A - Wafer-cleaning method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer-cleaning method which enables effective cleaning according to the contamination pattern and its device. SOLUTION: In a wafer-cleaning method, wherein a cleaning surface of a wafer 2 arranged on a rotatable wafer-supporting mechanism 5 is cleaned by a brush 10 which can be rotated and whirled, while a cleaning solution 41 is supplied, cleaning conditions corresponding to a whirling position of the brush 10 is set in advance, based on contamination pattern of a wafer cleaning surface and a wafer is cleaned changing wafer cleaning conditions based on whirling position information of the brush 10. Thereby, a wafer can be cleaned effectively according to contamination pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wafer cleaning apparatus, and more particularly to a wafer cleaning apparatus capable of performing high-efficiency cleaning by setting cleaning conditions based on wafer contamination position information.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, as a wafer becomes larger and smaller in diameter, a patterning step, a film forming step or a chemical mechanical polishing (CM) on a wafer surface is performed.
A flattening step and various other processing steps are performed by P), and a wafer cleaning process after these processing steps is required to have high layer accuracy. Wafer contamination, particularly contamination on the back surface of the wafer (the surface opposite to the surface on which the element is formed) is transferred by the chuck means because the back surface of the wafer is chucked during the above-described various processing steps. Account for the majority. These contaminants include, for example, reaction gas products and processing chemicals, slurries, polishing pad debris (organic substances), and polished oxides. This contaminant is at a specific position or has a specific shape depending on the shape of the suction head holding the wafer or the shape of the hand of the transfer unit, and often has a specific contamination pattern.

A conventional wafer cleaning apparatus includes a rotatable chuck mechanism for holding a wafer, a rotatable and pivotable brush and a side surface of the wafer for removing wafer contaminants disposed above the wafer. A cleaning liquid supply device for applying a cleaning liquid to a wafer surface from above is provided as a main component.

A conventional cleaning method using such a conventional cleaning apparatus is a method in which one wafer is chucked by a chuck mechanism to clean contaminants under the same cleaning conditions. That is, conventionally, the brush load indicating the degree of load (load) on the wafer cleaning surface, the cleaning rotation speed corresponding to the rotation speed of the rotating spindle, the brush rotation speed for rotating the brush on the wafer upper surface, and the brush itself at each rotation position Cleaning conditions such as a rotation speed and a flow rate of a cleaning liquid (rinse) supplied from a cleaning liquid supply device (substantially a supply pipe) have always been cleaned under constant conditions irrespective of a contaminant (contamination pattern) on a wafer surface.

[0005]

Therefore, when cleaning the back surface of a wafer having a specific contaminated pattern as described above, even a highly contaminated pattern portion on one wafer surface can be cleaned by another method. The part is also cleaned under the same cleaning conditions. Further, in the conventional method, although the cleaning conditions are substantially different between the inner peripheral portion and the outer peripheral portion of the wafer,
There is a restriction that only the same condition can be set as the setting condition. Under such cleaning conditions, it has been difficult to perform cleaning with high removal efficiency.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned prior art, and provides a high-efficiency wafer cleaning method and apparatus capable of efficiently cleaning a wafer under optimum conditions according to a contamination pattern. With the goal.

[0007]

According to the present invention, a cleaning surface of a wafer disposed on a rotatable wafer support mechanism is rotatable and pivotable while supplying a cleaning liquid. In a wafer cleaning method for cleaning with a brush, cleaning conditions corresponding to the turning position of the brush are set in advance based on the contamination pattern on the wafer cleaning surface, and cleaning is performed by changing the wafer cleaning condition based on the turning position information of the brush. A method for cleaning a wafer is provided.

[0010] According to this configuration, it is possible to set a cleaning condition with the highest removal rate based on the contamination position information of the wafer and to perform extremely efficient cleaning.

In order to further achieve the above object, the present invention provides a wafer support mechanism for placing and fixing a wafer, a rotatable and pivotable brush for removing contaminants on the wafer surface, In a wafer cleaning apparatus provided with a cleaning liquid supply apparatus, the wafer cleaning apparatus further includes control means for cleaning under predetermined cleaning conditions corresponding to a contamination pattern based on the turning position information of the brush. provide.

According to this configuration, the above-described method of the present invention can be carried out accurately, and the cleaning conditions with the highest removal rate can be set based on the contamination position information of the wafer, and extremely efficient cleaning can be performed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment,
The wafer cleaning condition includes one of a brush rotation speed, a turning speed, a brush load, a rotation speed of the wafer support mechanism, and a flow rate of the cleaning liquid.

According to this method, the cleaning conditions such as the rotation speed of the brush and the load are selected, and the cleaning conditions for cleaning the portion having the contaminants on the wafer surface and the portions for cleaning the portions having little or no contaminants are determined. The cleaning efficiency can be increased by appropriately changing the cleaning efficiency.

In a preferred embodiment, the brush is provided with a turning angle detecting means on a turning axis of the brush.

According to this configuration, it is possible to detect a brush turning angle based on a contamination pattern of a portion on the wafer surface with and without contaminants, and obtain brush turning position information from the turning angle.

In another preferred embodiment, the brush unit for holding the brush has a function of varying the rotation and / or rotation speed of the brush, and the control means controls the rotation and / or rotation of the brush based on the rotation position information of the brush. And / or the turning speed can be set.

According to this configuration, in the cleaning of a portion having contaminants on the wafer surface, the rotation speed of the brush is increased (or the rotation speed of the brush is decreased) so that sufficient cleaning can be performed.
On the other hand, in the cleaning of a portion having little or no contaminants, the brush turning speed is increased (or the rotation speed is reduced), and the cleaning efficiency can be increased as an optimal brush driving condition according to the contamination pattern.

In another preferred embodiment, the brush unit holding the brush has a brush weight variable function, and the control means can adjust the brush weight based on the turning position information of the brush. .

According to this configuration, the brush load is increased so that sufficient cleaning can be performed in a portion where the contaminant is present on the wafer surface, and the brush load is reduced in a portion where there is little or no contaminant. Cleaning efficiency can be improved.

In another preferred embodiment, the wafer support mechanism has a spindle rotation speed variable function, and the control means can increase or decrease the spindle rotation speed based on the turning position information of the brush.

According to this configuration, the number of rotations of the wafer support mechanism is increased so that sufficient cleaning can be performed in a portion where contaminants on the wafer surface are present, and in a portion where there is little or no contaminants, cleaning is performed. The cleaning efficiency can be increased by reducing the number of rotations of the wafer support mechanism.

In another preferred embodiment, the cleaning liquid supply device has a cleaning liquid flow rate adjusting function, and the control means can increase or decrease the cleaning liquid flow rate based on the turning position information of the brush.

According to this configuration, the flow rate of the cleaning liquid is increased so that sufficient cleaning can be performed when cleaning is performed on a portion having contaminants on the wafer surface, and the cleaning liquid flow rate is reduced when cleaning is performed on a portion having little or no contaminants. Cleaning efficiency can be improved.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic side view for explaining a wafer cleaning apparatus according to one embodiment of the present invention.
The wafer cleaning apparatus 1 shown in FIG. 1 has a rotating spindle 3 below a rotating spindle 3 for rotating the wafer 2.
A rotation detector 4 for detecting the number of rotations is mounted, and a chuck mechanism 5 and a chuck pin 6 similar to the conventional one for fixing the wafer 2 are provided above the rotation spindle 3. In FIG. 1, the wafer 2 is chucked by the chuck pins 6 and fixed on the chuck mechanism 5.

Above the wafer 2, a brush 10 for removing contaminants on the wafer surface is mounted on a horizontal shaft 11, which is mounted above a rotating shaft 11 which is arranged substantially vertically on the side of the rotary spindle 3 and the wafer chuck mechanism 5. The brush unit base 12 is attached downward at the tip end. On the opposite side of the tip of the horizontal brush unit base 12, that is, on the upper side, a brush weight unit 14 that rotates the brush 10 and adjusts the weight of the brush 10 against the wafer surface is provided.

The brush weighting unit 14 includes a brush rotation driving pulse motor 15 for controlling the rotation speed of the brush 10,
It is composed of a linear guide 16 with a built-in actuator for adjusting the weight of the brush, which can adjust the weight of the brush, a bracket 17 and a rotating shaft 18. Linear guide with built-in actuator for brush load (brush load control) 16
Is attached to the brush unit base 12, and a bracket 17 is attached to the brush load adjusting guide 16. The rotation shaft 18 transmits the rotation of the brush rotation drive pulse motor 15 to the brush 10. The brush rotation drive pulse motor 15 is mounted on a bracket 17, and the bracket 17 moves up and down by a brush load adjusting guide 16 to move the brush 10 up and down with respect to the wafer surface to adjust the load on the wafer 2.

A vertical slider 20 fixedly connected to the pivot 11 is disposed below the pivot 11. The vertical movement slider 20 is moved up and down by a brush vertical movement drive cylinder 21 arranged on the side. Thereby, the brush 10 is largely moved up and down via the turning shaft 11 and the brush unit base 12 at the time of wafer exchange or the like. A driven timing pulley 23 is attached below the vertical movement slider 20, and the brush is turned by a brush turning drive pulse motor 28 via a driving timing belt 24, a driving timing pulley 25, and a coupling 26. .

As means for controlling the brush turning speed, there are, for example, a cylinder with a speed control and a speed control motor as long as it can turn the brush. In this embodiment, the pulse motor is effective as described above. . A brush unit turning angle detection encoder 32 is provided below the driven timing pulley 23 at the end of the turning shaft 11 via a coupling 30. The brush unit turning angle detection encoder 32 is a means for detecting the brush unit turning angle. For example, a potentiometer or the like may be used instead of the encoder, but the encoder of this embodiment is preferable because it is easy to control.

A cleaning liquid (rinse) supply pipe 40 for supplying a cleaning liquid (rinse) 41 such as pure water to the surface of the wafer 2 is disposed above the peripheral edge of the wafer chuck mechanism 5. Although not shown, it is connected to an electronic mass flow controller as a means for controlling the flow rate of the cleaning liquid.

The operation of the present wafer cleaning apparatus will be described below with reference to FIGS. 1, 2 and 3. FIG. 3 is a flowchart of the cleaning process of the present invention.

As shown in FIGS. 1 and 2, the wafer 2 is fixed as usual by the chuck pins 6 of the wafer chuck mechanism 5. As shown in FIG. 2, the brush 10 turns around the brush turning center 50 along an arc-shaped brush turning locus 51 in the order of →→... → n. Since the contaminant (contamination pattern) 45 is specified in the previous process, the position of the contamination pattern 45 with respect to the brush turning position is calculated in advance, and position data of the contamination pattern is created.
Based on the position data, a series of cleaning is performed by setting a wafer rotation number, a rotation speed of the brush, a rotation speed, a brush load, a cleaning liquid (rinse) supply flow rate, and the like for each position data in accordance with the brush rotation operation. In this embodiment, the contaminant (contamination pattern) 45 is formed substantially at the center on the back surface of the wafer as shown in FIG.

In this case, first, the brush turning drive pulse motor 28 is driven so that the brush 10 is arranged at the center of the wafer 2. The turning force of the brush turning drive pulse motor 28 is controlled by the coupling 26 and the drive timing pulley 2.
5. The brush is transmitted to the rotating shaft 11 and the horizontal brush unit base 12 via the driving timing belt 24 and the driven timing pulley 23, and the brush is disposed at a predetermined position above the wafer 2, and thus is initially disposed above the central portion of the wafer 2. can do.

After the brush 10 is positioned above the central portion of the wafer 2, that is, at the position of the brush turning position in FIG. 2, the rotation of the brush is started (step S).
1). This position is detected via the encoder 32 (FIG. 1) (step S2). As the first cleaning conditions, the wafer rotation speed is N1 rpm, the brush rotation speed is n1 rpm, the brush weight is w1 g, and the cleaning liquid (rinse) is used.
The flow rate is set in advance as R1 ml / min. The motors are driven by a control device (not shown) so as to satisfy the cleaning conditions to clean the wafer (step S3). The rotation speed of the wafer 2 is obtained at a predetermined rotation speed by the spindle rotation speed detector 4, and the brush rotation speed is obtained at a predetermined rotation speed by the brush rotation drive pulse motor 15.
A predetermined weight is obtained by the brush weight guide 16 for brush weight. A large vertical movement of the brush for wafer replacement or maintenance is performed by a brush vertical drive cylinder 21 as in the conventional case.

In this manner, the cleaning by the rotation and the rotation of the brush is continued under the above-described cleaning conditions, and the brush is moved from the position (step S4). This is detected at the time when it reaches the position shown in FIG. 2 (step S5), and cleaning is performed by changing the cleaning conditions (step S6). The cleaning condition at this position is set to N2r as the wafer rotation speed as set in advance.
pm, brush rotation speed n2 rpm, brush weight w2
g, washing fluid (rinse) flow rate R2 ml / min.

Washing is continued under these washing conditions, and when the position shown in FIG. 2 is reached, washing is performed under different washing conditions (steps S7 to S9). This position is such that the contamination pattern 45 occupies approximately half of the brush in the state shown in the figure (actually, since the wafer is rotated, the averaged contamination of the contamination pattern trajectory along the circumference at this radial position). Amount). In the position (3), the cleaning conditions such as the weight of the brush are lowered from those described above. When the position of the brush is not applied to the contamination pattern 45, the cleaning condition can be further reduced to perform the cleaning.

Further, the brush is swirled to change the cleaning conditions for each predetermined position, and the cleaning operation is continued. When the final position n is reached (step S10), the position n is detected (step S11), cleaning is performed under the cleaning conditions at this position (step S12), and the brush rotation is completed (step S13), and the wafer is removed. Remove to end the cleaning process.

As described above, in this embodiment, the cleaning condition is set a necessary number of times (n times) based on the brush turning position information corresponding to the contamination pattern. Therefore, the processing flow from the start of brush rotation to the end of brush rotation is shown in FIG.

In the above embodiment, the cleaning conditions are set by paying particular attention to the shape of the contamination pattern 45. However, the cleaning conditions can be appropriately changed depending on the degree of contamination.

Although the present embodiment has been performed on the back surface of the wafer where a specific contamination pattern is particularly easily formed, the present invention is also applicable to the front surface of the wafer. In the above embodiment, the rotation speed of the brush itself by the motor 15 is changed as the cleaning condition, but the turning speed by the motor 28 may be changed.

[0039]

As described above, according to the present invention,
Since cleaning conditions with a high removal rate can be set based on the contaminant (contamination pattern) position information on the wafer surface, extremely efficient cleaning can be realized.

Further, since cleaning conditions according to the contamination pattern can be partially realized, unnecessary cleaning is eliminated, the life of the cleaning brush is extended, the consumption of cleaning liquid (rinse) can be reduced, and the cleaning efficiency is improved. I do.

[Brief description of the drawings]

FIG. 1 is a schematic side view for explaining an embodiment of a cleaning device according to the present invention.

FIG. 2 is a schematic plan view for explaining a relationship between a contamination pattern and a brush turning position.

FIG. 3 is a view showing a processing flow for explaining a cleaning method according to the present invention.

[Explanation of symbols]

1: Wafer cleaning device, 2: Wafer, 3: Rotary spindle, 5: Chuck mechanism, 6: Chuck pin, 10: Brush, 11: Rotating axis, 12: Brush unit base, 1
5: Brush rotation drive pulse motor, 16: Linear guide with built-in actuator for brush weight addition / reduction, 20: Vertical movement slider, 21: Brush vertical movement drive cylinder, 28: Brush rotation drive pulse motor, 32: Rotation angle detection encoder, 40: Cleaning liquid (Rinse) supply pipe, 45: contaminant (contamination pattern), 50: brush turning center, 51: brush turning position.

Claims (8)

[Claims] 1. A wafer cleaning method for cleaning a cleaning surface of a wafer placed on a rotatable wafer support mechanism with a rotatable and rotatable brush while supplying a cleaning liquid, wherein a contamination pattern on the wafer cleaning surface is provided. A cleaning condition corresponding to the turning position of the brush is set in advance based on the information of the brush, and cleaning is performed while changing the wafer cleaning condition based on the turning position information of the brush. 2. The cleaning method according to claim 1, wherein the wafer cleaning condition includes any one of a rotation speed of a brush, a rotation speed, a brush load, a rotation speed of the wafer support mechanism, and a flow rate of the cleaning liquid. Wafer cleaning method. 3. A wafer cleaning apparatus comprising: a wafer support mechanism for arranging and fixing a wafer; a rotatable and pivotable brush for removing contaminants on the wafer surface; and a cleaning liquid supply device. A wafer cleaning apparatus comprising: a control unit configured to perform cleaning under a predetermined cleaning condition corresponding to a contamination pattern based on the turning position information of the brush. 4. The wafer cleaning apparatus according to claim 3, wherein a turning angle detecting means is provided on a turning axis of the brush. 5. A brush unit for holding the brush,
The wafer cleaning apparatus according to claim 4, further comprising a brush rotation and / or rotation speed variable function, wherein the control unit can set the rotation and / or rotation speed of the brush based on the rotation position information of the brush. 6. A brush unit for holding the brush,
5. The wafer cleaning apparatus according to claim 4, further comprising a brush weight variable function, wherein the control unit can increase or decrease the brush weight based on brush turning position information. 7. The wafer cleaning apparatus according to claim 4, wherein said wafer support mechanism has a spindle rotation speed variable function, and said control means can increase or decrease said spindle rotation speed based on brush turning position information. apparatus. 8. The wafer cleaning apparatus according to claim 4, wherein said cleaning liquid supply device has a cleaning liquid flow rate adjusting function, and said control means can increase or decrease said cleaning liquid flow rate based on the turning position information of the brush.