This application relies for priority upon Korean Patent Application No. 2000-63885, filed on Oct. 3, 2000, the content of which is herein incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a cleaning apparatus for a semiconductor wafer. More particularly the present invention relates to a cleaning apparatus for a semiconductor wafer in which a spray nozzle is disposed near a brush, thereby allowing a uniform water screen to be formed on the surface of the wafer.
2. Description of the Related Art
Generally, as a wafer is enlarged, each of the devices on the wafer are formed at a higher density and the wafer becomes more highly integrated, whereby particles or metal impurities on the wafer pollute the wafer. This has the undesirable effect of deteriorating the yield and reliability of products made from the wafer. Accordingly, in order to remove various types of impurities such as particles, metal impurities, organic pollution, and surface film from the wafer surface, a separate wet cleaning process is performed after drying the wafer.
Such a conventional cleaning process is generally performed by a chemical cleaning method using chemicals, or by a spin scrubber cleaning method using a physical force. Of these methods, the spin scrubber cleaning method is widely used to remove impurities from wafers.
The spin scrubber wafer cleaning method can be classified into a cleaning method using pure water, a cleaning method using a brush, a cleaning method using ultrasonic waves, and so forth.
FIG. 1 is a schematic view showing a spin scrubber cleaning apparatus for a semiconductor wafer using pure water and a brush. As shown in FIG. 1, the spin scrubber cleaning apparatus includes a pure water supply 1, a filter 2, a solenoid valve 3, an injector 4, and a brush 6. The injector 4 has its output split into a first injector output 4a and second injector output 4b. The first injector output 4a has a first injector nozzle 5a attached to it, and the second injector output 4b has a second injector nozzle 5b attached to it.
Pure water supplied from the pure water supply 1 is further purified by passing through the filter 2 and continues through the solenoid valve 3 and injector 4, the first and second injector outputs 4a and 4b, and the first and second injector nozzles 5a and 5b. Ultimately, the pure water is ejected onto the wafer 7, which has a specified wafer pattern formed thereon, to form a water screen pattern on the wafer 7. Particles on the wafer 7 are then physically removed using the brush 6. The cleaning method of using a spin scrubbing apparatus is called a spin scrubber process.
During this process, pure water is usually supplied to the wafer 7 through the first and second injector nozzles 5a and 5b. The first injector output 4a is positioned toward the center of the wafer 7, and the second injector output 4b is positioned toward the central portion between the center and edge of the wafer 7. These two injectors 4a and 4b eject pure water onto the surface of the wafer 7 through respective nozzles 5a and 5b when the wafer rotates, so that a water screen is formed on the surface of the wafer. Particles on the wafer 7 are physically removed by the brush 6 when the wafer 7 rotates, while the water screen is formed on the wafer 7. During this process, the brush 6 is either in contact with the surface of the wafer 7 or is spaced from the wafer by at interval of 0.5 xcexcm, for example.
However, the water screen formed on the wafer can become irregular due to variations in the position and the ejecting pressure of the injector nozzles 5a and 5b. Accordingly, contact between the brush 6 and the wafer 7 can become unstable. As a result, the surface of the wafer can become damaged partly by excessive contact force between the brush 6 and the wafer 7. Alternatively, the particles might only be partly removed because of lack of contact between the wafer 7 and the brush 6, thereby deteriorating the product and its reliability in process.
The present invention is therefore directed to a cleaning apparatus for a semiconductor wafer which substantially overcomes one or more of the problems due to the limitations and disadvantages of the related art.
It is an object of the present invention to provide a wafer cleaning device in which a brush is integrally formed with a nozzle that supplies pure water, to form a uniform water screen on the surface of a wafer, so that particles on the wafer can be entirely removed.
It is another object of the present invention to provide a wafer cleaning device by which contact between a brush and a wafer is uniformly maintained, thereby raising the efficiency of semiconductor cleaning.
In order to accomplish these and other objects, a cleaning device according to the present invention comprises a pure water supply; first and second injectors for ejecting pure water supplied from the pure water supply onto a wafer; first and second nozzles attached to ends of the respective first and second injectors; a brush for cleaning the wafer by moving horizontally between the center to the edge of the wafer; and a brush arm for supporting and moving the brush. The first injector ejects the pure water at an upper position of the wafer toward the center wafer, and the second injector is disposed adjacent to the brush along one side of a brush arm, and supplies the pure water toward the wafer.
The second nozzle may be disposed such that it faces a top surface of the wafer that is in contact with the brush. The first injector may be arranged to be perpendicular to the second injector. The brush may move horizontally in response to the direction of the first injector.
In an alternate design, a cleaning device is provided that comprises a pure water supply; a first injector for ejecting pure water supplied from the pure water supply onto a central portion of the wafer; a plurality of second injectors for ejecting pure water supplied from the pure water supply onto the wafer; a first nozzle attached to the first injector; a plurality of second nozzles attached to respective second injectors; a brush for cleaning the wafer by moving horizontally between the center and the edge of the wafer while the pure water is ejected by the first and second nozzles; and a brush arm for supporting and moving the brush. The plurality of second injectors comprise a plurality of pipe lines formed along a circumference of the brush arm, the end of the pipelines facing a top surface of the wafer.
The plurality of second injectors may be tightly fixed to the brush arm by a fixing apparatus. The first injector may be arranged to be perpendicular to the plurality of second injectors.
In these embodiments, the brush arm may move in a direction parallel to a linear orientation of the first injector. The brush arm may also move vertically to either keep the brush a desired distance from a surface of the wafer, or to keep the brush in contact with the surface of the wafer.