JPH11307490A - Rotary cleaning method for wafer and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain cleaning efficiency equal to or more than that in a mechanical rotation which rotates by a conventional drive roller in rotary cleaning of a wafer in which the wafer is dipped in a solution of pure water or a detergent, and cleaning is performed efficiently by rotating the wafer. SOLUTION: In a state that a wafer basket 3 is dipped in a solution bath, as rotating means for rotating a wafer W in a circumferential direction, solution flow or bubbles flow jetting means is provided at a position confronted to an opening of the basket 3, and a fluid jetting direction of this jetting means is directed to a direction along a peripheral face or a margin of the wafer on one side near to a center position of the wafer W in the basket 3, and the wafer W is rotated in a circumferential direction by this solution flow, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for rotating and cleaning a wafer, in which a wafer is immersed in pure water, a cleaning solution, or a liquid of a chemical solution, and the wafer is rotated to efficiently clean the wafer.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, wafer surface contaminants degrade device characteristics and are a major cause of defects. Therefore, in order to manufacture products with high yield and high reliability, it is necessary to remove contaminants in each step of the wafer manufacturing process. Various cleanings, for example, cleaning after etching, final cleaning in the wafer manufacturing process, RCA cleaning And various wet cleaning processes such as rinsing cleaning (pure water cleaning).

[0003] Such a wafer cleaning technique replaces the conventional brush contact type cleaning method in which a brushing or a scrubber contacts the wafer surface. In order to improve the cleaning efficiency after immersing the wafer in a basket in pure water, Cleaning is performed by rotating the wafer while bubbling as necessary. In such a cleaning method, a mechanical rotation method is used to rotate the wafer.

FIG. 3 shows a configuration of a conventional wafer cleaning apparatus for mechanically rotating a wafer. In the figure, reference numeral 11 denotes a rinsing tank, and 12 denotes a pure water blowing part (nozzle) juxtaposed at the bottom of the rinsing tank. Pure water blown from the pure water blowing part (nozzle) 12 contacts the peripheral surface of the wafer W. Reference numeral 13 denotes a wafer basket for arranging a large number of wafers W along a substantially vertical plane in the front-rear direction in the figure. It is engraved.

Reference numeral 14 denotes a pair of swinging tables on which the legs of the basket 13 are placed on both sides. The swinging tables 14 are arranged so that the basket 13 is located above the pure water blowing section 12 and the swinging tables. The basket 13 through the bull 14
Is configured to be swingable. Reference numeral 17 denotes a drive roller which comes into contact with the lower end of the peripheral edge of the wafer through the basket lower opening, and the rinsing tank 1 is connected to a rinsing tank 1 via a conductive system (not shown) provided outside the rinsing tank 11.
1 is configured to be rotatable by a rotation drive device 18 provided on the lower surface.

According to this conventional technique, the rotation of the drive roller 17 causes the wafer W in contact therewith to be driven to rotate (16 in the figure), and at the same time, causes the nozzle 12 to eject pure water upward to eject the wafer W. Perform efficient cleaning.
In the prior art, the driving roller 17 receives a load in the gravitational direction of the wafer W and is in contact with the lower peripheral edge of the wafer W. In other words, the driving roller 17 receives the load of the wafer W. Nozzle 1
Even if pure water is spouted onto the peripheral surface of wafer W from wafer 2, wafer W
Does not rotate. Since the jet of pure water from the nozzle 12 is almost uniformly jetted on both the left and right sides of the drive roller 17, it has no effect on the rotational energy of the wafer W.

[0007]

However, in the above-described mechanical rotation method, a drive roller and a rotation drive device are required, so that not only the size of the device is inevitably increased, but also the equipment cost is increased. Further, in the mechanical rotation method, since the driving roller 17 is brought into contact with the peripheral edge of the wafer W to apply a driven rotational force to the wafer W, particles are easily generated due to the friction between the driving roller 17 and the peripheral edge of the wafer W.

SUMMARY OF THE INVENTION In view of the above technical problems, an object of the present invention is to provide a method for rotating a wafer and a device for rotating the wafer without increasing the size of the apparatus and without increasing the equipment cost. It is still another object of the present invention to provide a method and an apparatus for rotating a wafer that can be efficiently cleaned without generating particles.

[0009]

According to the first aspect of the present invention,
The wafer is stored in a wafer storage unit (wafer basket) having an opening at an appropriate position to store and support the wafer rotatably in the circumferential direction, and is immersed in a liquid tank filled with a chemical solution or pure water. In a method of rotating a wafer for cleaning the wafer while rotating the wafer in a circumferential direction, a liquid flow, a bubble flow, or a wake generated by the flow is mainly used for a wafer peripheral surface or a peripheral edge on one side from a center position of the wafer. While contacting
The wafer is rotated in the circumferential direction by the contacted liquid flow or the like.

A second aspect of the present invention relates to an apparatus for suitably implementing the above-mentioned invention, and includes a wafer storage portion (wafer basket) having an opening at an appropriate position for storing and supporting a wafer rotatably in a circumferential direction. , Also referred to as a basket), comprising a liquid tank filled with a chemical solution or pure water, and rotating means for rotating the wafer in the circumferential direction in a state where the wafer storage portion is immersed in the liquid tank, In a wafer rotary cleaning apparatus for cleaning the wafer while rotating the wafer by the rotating means, a liquid flow or bubble flow blowing means (hereinafter referred to as a blowing nozzle) is provided at a position facing the wafer storage section opening, The fluid ejection direction of the ejection means is set such that the wafer is located on one side of the center position of the wafer stored in the wafer storage portion mainly through the opening of the basket. It is characterized in that for the constant direction along the circumferential surface or perimeter.

According to this invention, since the wafer is rotated by a liquid flow or a bubble flow, and the present invention can be achieved only by changing the ejection direction of the above-mentioned conventional ejection nozzle, the conventional machine is used. There is no need for a drive roller or a rotation drive device unlike the conventional rotation method. Therefore, according to the present invention, the size of the apparatus is smaller than that of the conventional apparatus, and the equipment cost is reduced. Further, in the present invention, since only the liquid flow or the bubble flow comes into contact with the wafer, and the ejection nozzle does not come into contact with the wafer or the basket at all, there is no room for particles or the like to be generated by the rubbing thereof, and the cleaning efficiency is improved.

As the liquid flow, a chemical liquid is used in the case of a chemical tank, and pure water is used in the case of a rinse tank. Further, the wafer may be rotated by a liquid flow that is circulated by the bubble flow by injecting the bubble flow by the ejection nozzle. As the chemical,
A general cleaning solution combining ammonia, hydrogen peroxide, hydrofluoric acid, hydrochloric acid, water and the like is used. In addition, the jet velocity of the liquid flow or the bubble flow requires velocity energy such that the wafer can rotate against the resistance of the basket with the support groove when the fluid flow velocity contacts the wafer. It is preferable that the rotation speed of the wafer is given such a rotation energy that the generation rate of surface contamination can be reduced. In addition, the upper limit of the ejection speed is, in terms of the cost of using air bubbles or liquid,
It is preferable to suppress the occurrence of a trouble such as a wafer jumping out.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, unless otherwise specified, dimensions, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the invention, but are merely illustrative examples.

FIG. 4 shows a wafer basket 3 used in the present invention. As shown in FIG. 4A, which is a cross-sectional view taken along the line AA of FIG. Left and right side walls 3
As shown in the plan view of FIG. 3A, V-shaped wafer support grooves 33a to 33c are sawn in the upper, middle, and lower stages on the inner peripheral side of the side walls 31, 32, which are held by the side walls 31, 32. A large number of wafers W are vertically arranged in parallel in the figure while a large number of wafers W are held vertically in the support grooves 33a to 33c. (B) is a front view. As a result, the wafer W
Is supported in substantially vertical contact with the support grooves 33a to 33c in a substantially vertical plane, so that the wafer W can be easily rotated by applying rotational energy in the circumferential direction in the vertical plane.

The upper surface 34 of the wafer basket 3
The bottom surface 35 has a large opening so that the wafer W can be stored / removed from the top surface 34, and the pure water jet flow described later is opened from the bottom surface 35 side. The basket 3 is also provided with band-shaped openings 36 on the upper and lower sides of the left and right side walls 31 and 32 with the support groove 33b provided at the middle level interposed therebetween, thereby facilitating intrusion of the jet of pure water.

FIGS. 1 and 2 show the configuration of a wafer cleaning apparatus according to an embodiment of the present invention for rotating a wafer W by a liquid flow, particularly a rinse tank after etching. In the figure, reference numeral 1 denotes a rinsing tank, as shown in FIG. 2, in which the plurality of wafer baskets 3 described above can be immersed and arranged in the longitudinal direction.
Reference numeral 4 denotes a pair of swinging tables on which the legs of the basket 3 are placed on both sides in order to arrange the basket 3 in the rinsing tank 1 in a hollow state.
And a swing rod 42 provided at the upper end of the vertical support rod 41.
Is configured to be able to swing at a predetermined angle via.

Between the swing table 4 and the bottom of the rinsing tank 1, there are provided two groups of pure water blowing nozzle pipes in which four tubular nozzles extending in the longitudinal direction of the rinsing tank 1 are juxtaposed in the transverse direction of the rinsing tank. ing. Although the disposition position of the nozzle tube 2 is not limited, the nozzle tube 2 is disposed at a position facing the bottom opening 35 of the basket 3, and the nozzle hole 20 (pure water jetting direction) is inserted through the bottom opening 35 into a wafer basket. The wafer W accommodated in 3 is oriented in a direction substantially tangential to the peripheral edge of the wafer W on one side from the center position of the wafer W stored in the wafer 3.

That is, the nozzle tube 2a located on the outside (right) side of the table located on one side from the center position of the wafer W is set so that pure water blows out vertically, and the nozzle tube 2a is located on the inside (left) side of the table. The nozzle pipes 2b to 2d located are inclined to the right side in the drawing and their nozzle holes 20 are set so that pure water is blown out. The speed and amount of pure water blown out from the nozzle tube 2 are set to such a speed and amount that the pure water jet can contact the peripheral edge of the wafer and impart rotational energy.

The nozzle holes 20 are set to be equal to or approximately 3 to 5 times the interval of the wafers W arranged in the basket 3 so that the jets 5 can surely hit each of the arranged wafers W. It is preferable that the interval between the nozzle holes 20 is set to about 5 to 10 times the interval between the rows of the wafers W because the wake generated by the jet 5 also has rotational energy. no problem. For example, in the present apparatus, each nozzle hole 20 has a hole having a size of
Perforated at intervals.

Next, the operation of the embodiment will be described. First, as described above, a washing apparatus is prepared in which the four nozzle pipes 2 are arranged below the swing table 4 at the bottom of the rinsing tank 1 in which a plurality of baskets 3 into which a plurality of wafers W can be placed are set. A basket 3 containing an 8-inch wafer W after alkali etching is set on the swing table 4 of the rinsing tank 1. In this apparatus, pure water is supplied 7 from the outside, and pure water can always be ejected from the nozzle hole 20. At this time, the direction in which the pure water is ejected from the nozzle hole 20 is adjusted so that the pure water is concentrated at a position where the wafer W rotates (6 in the drawing), for example, at one edge of the wafer W described above. The jet velocity of pure water is 0.01cm / sec
c is set.

The rinsing tank 1 has an 8-inch wafer W40
The two baskets 3 on which the sheets are set are fixed on the swing table 4, and the wafer W is rotated while being swung at a swing angle that does not hinder the rotation, thereby performing cleaning. At this time, the pure water supplied from the nozzle tube 2 rubs the surface of the wafer W while applying rotational energy to the wafer W.
Cleaning is performed while overflowing from the rinsing tank 1.

In this cleaning step, when the cleaning time was 3 minutes, the appearance stain defect was reduced by 1% as compared with the conventional example shown in FIG. No increase in particles was observed.
In addition, the jetting speed of pure water was 0.005 cm
In the case of / sec, some wafers W did not rotate, and stable rotation was not obtained. Accordingly, in the case of the present embodiment, it was confirmed that the wafer W was rotated stably by the injection speed of the pure water of 0.01 cm / sec or more. It varies arbitrarily depending on the interval, the number of baskets, the number of wafers, the wafer diameter, the type of basket, and the like.

In the present embodiment, pure water is always injected, but pure water injection may be started after the wafer W is set. Although a table for setting the basket 3 is necessary, the table does not always have to be swung. Pure water may be circulated without being supplied from the outside, but it is easier to supply pure water from the outside in view of the structure of the apparatus and cleanliness. In the embodiment, the rinsing step after the etching is applied, but the same applies to other various wet cleaning steps. Although the purpose is different from that of cleaning for removing surface contaminants, a similar method and apparatus can be used in a wet etching process using an acid or alkali as a chemical solution.

[0024]

As described above, according to the present invention, it is possible to obtain a cleaning efficiency equal to or higher than that of a mechanical rotation in which a conventional drive roller rotates. Also, unlike the prior art, the space for mounting the driving parts by installing the rotating mechanism is not required, so that the apparatus can be made compact and the structure can be simplified, so that the cost of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing the configuration of a wafer cleaning apparatus according to an embodiment of the present invention for rotating a wafer by a jet of pure water, particularly a rinse tank after etching.

FIG. 2 is a side view of FIG.

FIG. 3 is a view corresponding to FIG. 1 showing a configuration of a wafer cleaning apparatus according to a conventional technique in which a wafer is mechanically rotated by a driving roller.

FIG. 4 shows a wafer basket used in the present invention;
(A) is a plan view, (B) is a front view, (C) is A of (A).
FIG.

[Explanation of symbols]

 Reference Signs List 1,11 Rinse tank 2,12 Nozzle 3,13 Wafer basket 4,14 Table 5,15 Pure water flow 6,16 Wafer rotation 17 Drive roller (wafer contact part) 18 Drive device W Wafer

Claims (2)

[Claims] 1. A state in which a wafer is stored in a wafer storage portion having an opening at an appropriate position for storing and supporting the wafer rotatably in a circumferential direction, and is immersed in a liquid tank filled with a chemical solution or pure water. In a method of rotating a wafer for cleaning the wafer while rotating the wafer in the circumferential direction, the liquid flow or the bubble flow or the wake generated by the wafer flow is mainly used for the wafer peripheral surface on one side from the center position of the wafer or A method of rotating and cleaning a wafer, wherein the wafer is rotated in the circumferential direction by the contacted liquid flow or the like while being in contact with a peripheral edge. 2. A wafer storage part having an opening at an appropriate position for storing and supporting a wafer rotatably in a circumferential direction, a liquid tank filled with a chemical solution or pure water, and a wafer storage part in the liquid tank. A rotating means for rotating the wafer in a circumferential direction in a state of being immersed, in a wafer rotary cleaning apparatus for cleaning the wafer while rotating the wafer by the rotating means, A liquid flow or bubble flow ejection means is provided at a position facing the wafer, and the fluid ejection direction of the ejection means is set to a direction along a wafer peripheral surface or a peripheral edge on one side from a center position of the wafer stored in the wafer storage portion mainly through the opening. A rotary cleaning device for wafers, characterized in that