JP2002093767A - Single wafer cleaning equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent contamination with particles caused by rotation. SOLUTION: The single wafer cleaning equipment comprises a disc stage 13 disposed rotatably in horizontal state in a chamber 11 and holding a single wafer 12 on the upper surface thereof, and a nozzle 14 for supplying cleaning liquid onto the surface of the wafer wherein the wafer is cleaned by spreading the cleaning liquid over the entire surface of the wafer with centrifugal force. In this equipment, a bottom plate 11a is formed of a nonmagnetic material, a first central magnet 13a is disposed in the center of the bottom face of the stage, and a plurality of first circumferential magnets 13b are disposed at the circumference of the bottom face. A second central magnet 11b having the same tip polarity as that of the first central magnet is bonded to the upper surface of the bottom plate facing the first central magnet, a drive disc 16 having the same center of rotation as the stage is provided on the outside of the chamber, a plurality of second circumferential magnets 16a having a tip polarity different from that of the first circumferential magnet are provided oppositely to the first circumferential magnets on the upper surface of the disc, and a rotary shaft 17 is bonded to the center of the disc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a single wafer type wafer cleaning apparatus used for cleaning the surface of a silicon wafer. More specifically, the present invention relates to a single-wafer cleaning apparatus that does not generate dust due to driving of the apparatus.

[0002]

2. Description of the Related Art The number of basic steps in the production of silicon wafers is over 200, of which the number of cleaning steps is about 1 /.
Occupies three. After the mirror-polished wafer processing, cleaning for removing impurities and fine particles from the wafer surface is performed before and after many processes such as oxidation, impurity diffusion, ion implantation, CVD, and lithography. Therefore, the most suitable cleaning methods before and after each step have been developed. Cleaning generally involves chemical cleaning (Chemical Cleanin
g) and Mechanical Cleaning.
Chemical cleaning is roughly classified into wet cleaning (wet cleaning) using a cleaning solution and dry cleaning (dry cleaning) using a cleaning gas.

[0003] Among them, a single-wafer type cleaning apparatus for cleaning silicon wafers one by one has been proposed as one measure for improving the cleaning effect by using wet cleaning. FIG. 4 is a schematic diagram of a single wafer cleaning apparatus. In this apparatus, a disk-shaped stage 3 is rotatably provided in a horizontal state inside the chamber 1 at a predetermined distance from the bottom plate of the chamber 1. This disk-shaped stage 3 holds a single wafer 2 on the upper surface. A nozzle 4 for supplying a cleaning liquid to the surface of the wafer 2 is provided above the disk-shaped stage 3. Nozzle 4
Is connected to the cleaning liquid supply device via the arm 4a. A rotating shaft 6 is provided outside the chamber 1. The rotating shaft 6 passes through the bottom plate of the chamber 1 and is fixed to the center of the bottom surface of the stage 3. The through portion of the bottom plate of the chamber 1 through which the rotating shaft 6 has passed is sealed by a seal portion 7.

In the apparatus configured as described above, the stage 3 inside the chamber 1 is horizontally rotated via the seal portion 7 by driving the rotating shaft 6 provided outside the chamber 1, and the wafer 4 is The cleaning liquid is supplied to the surface of the wafer 2 and the cleaning liquid is uniformly spread over the entire surface of the wafer 2 by the centrifugal force generated by the rotation of the stage 3 to clean the wafer. By using the above-mentioned single wafer cleaning apparatus, it is possible to perform extremely effective cleaning without causing cleaning unevenness, as compared with an apparatus for simultaneously cleaning a plurality of wafers.

[0005]

However, in the above-described conventional single wafer type wafer cleaning apparatus, the rotating shaft and the stage are connected through the bottom plate of the chamber through the seal portion, so that the rotating shaft is driven. As a result, there is a problem that contamination such as particles enters the chamber from the seal portion and contaminates the wafer. An object of the present invention is to provide a single-wafer type wafer cleaning apparatus capable of preventing contamination of particles and the like due to rotation.

[0006]

The invention according to claim 1 is
As shown in FIG. 1, a disk-shaped stage 13 is provided rotatably in a horizontal state inside a chamber 11 at a predetermined distance from a bottom plate 11a of the chamber 11 and holds a single wafer 12 on an upper surface; Wafer 1 held in
And a nozzle 14 for supplying a cleaning liquid to the nozzle 2.
Cleaning liquid supplied to the surface of the wafer 12 by the stage 1
This is an improvement of a single wafer cleaning apparatus configured to clean the wafer 12 by uniformly spreading over the entire surface of the wafer 12 by the centrifugal force generated by the rotation of the wafer 3. The characteristic configuration is that the bottom plate 11 a of the chamber is formed of a non-magnetic material, and the first center magnet 1
3a is fixed, and a plurality of first
A peripheral magnet 13b is arranged, and a second center magnet 11b having the same tip polarity as the tip polarity of the first center magnet 13a is provided on the upper surface of the bottom plate 11a of the chamber facing the first center magnet 13a at an interval from the first center magnet 13a. A driving disk 16 is provided outside the chamber 11 at a predetermined distance from the bottom plate 11a of the chamber so as to be rotatable in a horizontal state and has the same rotation center as the stage 13. A plurality of first peripheral magnets are provided. A plurality of second peripheral magnets 16a having a tip polarity different from that of the tip 13b are provided on the upper surface of the disk 16 so as to face the first peripheral magnet 13b.
The rotation shaft 17 for rotating the shaft is fixed. In the invention according to claim 1, since the stage 13 is floated by the repulsion of the mutual magnetic force between the first center magnet 13a and the second center magnet 11b, the contact between the chamber 11 and the stage 13 can be prevented. Further, the bottom plate 11a of the chamber is made of a non-magnetic material, and the stage 13 is rotated by attracting the mutual magnetic force of the first peripheral magnet 13b and the second peripheral magnet 16a, so that the conventional sealing portion is not required. .
As a result, dust generation due to the rotation of the stage and the rotating shaft does not occur, so that contamination of the wafer can be prevented.

[0007]

Next, an embodiment of the present invention will be described. As shown in FIG. 1, in the single wafer cleaning apparatus 10 of the present invention, the bottom plate 11a of the chamber 11 is formed of a non-magnetic material made of a synthetic resin such as a vinyl chloride resin. The bottom plate 11a is coated with tetrafluoroethylene (trade name: Teflon) on the surface of the non-magnetic material in order to impart resistance to a cleaning solution used for cleaning. Inside the chamber 11, a disk-shaped stage 13 that holds a single wafer 12 on the upper surface at a predetermined interval from the bottom plate 11a is rotatably provided in a horizontal state. A first center magnet 13a is fixed to the center of the bottom surface of the stage 13,
A plurality of first peripheral magnets 13b are arranged on the periphery of the bottom surface of the stage 13. FIG. 2 shows a bottom view of the stage 13. First
Either the N pole or the S pole may be used as the tip polarity of the center magnet 13a. In this embodiment, it is an N pole. As the plurality of first peripheral magnets 13b, magnets having the same tip polarity are all used, and either the N pole or the S pole may be used. In this embodiment, it is an N pole. The first peripheral magnet 13b depends on the magnetic force of the magnet.
It is preferable to arrange the peripheral magnets 13b at equal intervals. In this embodiment, twelve are arranged at equal intervals.

Returning to FIG. 1, a second center magnet having the same tip polarity as the tip polarity of the first center magnet 13a is provided on the upper surface of the bottom plate 11a facing the first center magnet 13a at a distance from the first center magnet 13a. 11b is fixed. In this embodiment, it is an N pole. The size of the second center magnet 11b is preferably the same as the size of the first center magnet 13a, and the magnetic force is preferably substantially the same. Above the stage 13, a nozzle 14 for supplying a cleaning liquid to the wafer 12 held on the stage 13 is provided. A pulley 14b, a belt 14c, and a motor 14d are connected to the nozzle 14 following the arm 14a. The nozzle 14 is connected to a cleaning liquid supply device. Outside the chamber 11, there is provided a driving disk 16 rotatable in a horizontal state at a predetermined distance from the bottom plate 11 a and having the same rotation center as the stage 13. A plurality of second peripheral magnets 16a having tip polarities different from those of the first peripheral magnets 13b are provided on the upper surface of the disk 16 so as to face the first peripheral magnet 13b. In this embodiment, it is the south pole. FIG. 3 shows a top view of the driving disk 16. The size of the second peripheral magnet 16a is the first peripheral magnet 13
The size of b is preferably the same, and the magnetic force is preferably substantially equal.
The number of the second peripheral magnets 16a is the same as the number of the first peripheral magnets 13b for controlling the rotation and maintaining the stability of the stage. In this embodiment, twelve are arranged at equal intervals. A rotating shaft 17 for rotating the disk 16 is fixed to the center of the disk 16. The first central magnet 13a, the second central magnet 11b, and the first peripheral magnet 13b that come into contact with the cleaning liquid in the chamber 11 prevent contamination caused by the magnet,
Preferably, the surface of each magnet is coated.

In the apparatus configured as described above, first, the wafer 12 is held on the upper surface of the stage 13. The stage 13 holding the wafer 12 includes a first center magnet 13a disposed at the center of the bottom of the stage and a bottom plate 11 of the chamber 11.
(a) The second center magnet 11b fixed to the upper surface is arranged so as to oppose with an interval. Since the tip polarity of the first center magnet 13a and the tip polarity of the second center magnet 11b have the same polarity, if they are arranged so as to face each other at intervals,
Since the first center magnet 13a and the second center magnet 11b repel each other, the stage 13 is held in a floating state without contacting the bottom plate 11a. By arranging the stage 13 so that the first center magnet 13a and the second center magnet 11b face each other, the plurality of first periphery magnets 13b and the plurality of second periphery magnets 16a also face each other at intervals. Since the first peripheral magnet 13b and the second peripheral magnet 16a have different tip polarities, their mutual magnetic forces attract each other. The first center magnet 13a and the second center magnet 11b, which are magnetic forces repelling to hold the stage 13 in a floating state, have a larger magnetic force than the first peripheral magnet 13b and the second peripheral magnet 16a, which are attractive magnetic forces. Is used. Since the stage 13 is supported not only by the magnetic force at the center but also by the magnetic force at the peripheral edge, the stage 13 is always kept horizontal.

Next, the rotating shaft 17 is driven to rotate the driving disk 16 fixed thereto. As described above, the second peripheral magnet 16a provided on the upper surface of the driving disk 16 and the first peripheral magnet 13b opposed to each other across the bottom plate 11a of the chamber made of a nonmagnetic material are attracted by mutual magnetic force. Because they match, they are always fixed at the same position. Therefore, by rotating the driving disk 16, the disk stage 13 to which the first peripheral magnet 13 b is fixed also rotates in the same manner as the rotation of the driving disk 16. Thus, since the rotation mechanism conventionally incorporated in the chamber can be provided outside the chamber, dust generation due to rotation can be prevented. Next, the cleaning liquid is supplied to the center of the surface of the wafer 12 by the nozzle 14 while rotating the stage 13. The supplied cleaning liquid is a chemical or pure water. Wafer 12
The cleaning liquid supplied to the surface flows in the radial direction of the wafer due to the centrifugal force generated by the rotation of the stage 13, and the wafer 1
2 Evenly spread over the entire surface. Since the cleaning liquid uniformly spreads over the wafer surface, extremely effective cleaning can be performed without causing cleaning unevenness. After the cleaning, gas is injected into the chamber by gas supply means (not shown) to dry the wafer surface. The gas is an inert gas, preferably N ₂ gas. The used cleaning liquid and gas to be injected into the chamber are guided to the outside of the chamber by exhaust / drainage means (not shown).

[0011]

As described above, according to the present invention, since the bottom plate of the chamber is made of a non-magnetic material in the single wafer cleaning apparatus, magnetic force can be used for the driving means, and the center of the bottom of the stage can be used. The first central magnet has a plurality of first peripheral magnets arranged on the bottom surface periphery, and has the same tip polarity as the first central magnet at an interval from the first central magnet on the upper surface of the bottom plate of the chamber opposed to the first central magnet. Since the second center magnet is fixed, the stage can be held in a floating state, a driving disk having the same rotation center as the stage is provided outside the chamber, and has a tip polarity different from that of the first peripheral magnet. A plurality of second peripheral magnets are provided on the upper surface of the disk so as to face the first peripheral magnet, and the rotating shaft is fixed to the center of the disk, so that the stage rotates without contacting the chamber or the rotating shaft, and rotates. There since installed outside the chamber, the seal portion as in the prior art becomes unnecessary. As a result, no dust is generated on the stage or the rotating shaft, and contamination of the wafer can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic view of a single wafer cleaning apparatus of the present invention.

FIG. 2 is a bottom view of a stage of the single wafer cleaning apparatus of the present invention.

FIG. 3 is a top view of a driving disk of the single wafer processing apparatus of the present invention.

FIG. 4 is a schematic diagram of a conventional single wafer cleaning apparatus.

[Explanation of symbols]

 Reference Signs List 11 chamber 11a bottom plate 11b second center magnet 12 wafer 13 disk stage 13a first center magnet 13b first peripheral magnet 14 nozzle 16 driving disk 16a second peripheral magnet 17 rotating shaft

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazunari Takaishi 1-297 Kitabukuro-cho, Omiya-shi, Saitama Mitsubishi Materials Silicon Research Center F-term (reference) 3B201 AA03 AB01 AB34 AB42 BB22 BB92 BB93 CB01

Claims (1)

[Claims] 1. A disk which is provided rotatably in a horizontal state inside said chamber (11) at a predetermined distance from a bottom plate (11a) of the chamber (11) and holds a single wafer (12) on an upper surface. Stage (13), a nozzle (14) for supplying a cleaning liquid to the wafer (12) held on the stage (13), the cleaning liquid supplied to the wafer (12) surface by the nozzle (14) The wafer (12) is spread evenly over the entire surface of the wafer (12) by the centrifugal force generated by the rotation of the stage (13).
In the single wafer cleaning apparatus configured to clean the substrate, a bottom plate (11a) of the chamber is formed of a non-magnetic material, and a first center magnet (13a) is fixed to a center of a bottom surface of the stage (13). A plurality of first peripheral magnets (13
b) is disposed, and the bottom plate of the chamber facing the first center magnet (13a)
(11a) A second center magnet (11b) having the same tip polarity as the tip polarity of the first center magnet (13a) is fixed on the upper surface at an interval from the first center magnet (13a), and a bottom plate of the chamber is provided. A driving disk (16) that is rotatable in a horizontal state and has the same rotation center as the stage (13) is provided outside the chamber (11) at a predetermined interval from (11a), A plurality of second peripheral magnets (16a) having a tip polarity different from the tip polarity of the first peripheral magnet (13b) are provided on the upper surface of the disk (16) in opposition to the first peripheral magnet (13b), A rotation axis for rotating the disk (16) at the center of the disk (16)
A single wafer cleaning apparatus characterized in that (17) is fixed.