Abstract:
There is disclosed a cleaning device for cleaning a semiconductor wafer. According to the present invention, ech of the steps of the cleaning process used a separate carrier, so that none but the wafers need be washed, saving washing time. When drying, the surfaces of the wafers are kept from being contaminated by residual cleansers, thereby improving the yield rate.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a cleaning device for cleaning a wafer on the manufacture of semiconductor device. Specifically, the invention is directed to the device wherein there is exclusively used a separate carrier in each of the several stages of the cleaning process, so that the contamination of the cleaning product can be prevented. 
     Conventionally, a wafer fabrication stage for the manufacture of semiconductor device requires a cleaning process in which the wafer is extremely cleaned out by a chemical cleaning product prior to processing each unit prior to fabricating a semiconductor device using the wafers. The cleaning process generally includes the steps of removing the impurities from the surface of the wafer by using the cleanser of NH 4  OH cleaning said wafer in a pure water bath so as to remove the remnants of the cleanser on the surface of the wafer, washing again the wafer by using the cleanser of HCI, cleaning the wafer in the pure water so as to remove the cleanser, washing the wafer in the pure water bath so as to completely remove the cleansers and impurities, and finally drying the wafer. This process usually takes about 5 to 10 minutes in total. 
     In such a known process, the carrier that holds therein a plurality of wafers is processed without changing said carrier in a single cleaning process, until the cleaning process will be completed prior to other fabrication stage. On the other hand, because the Teflon carrier itself used presently tends to absorb a part of the cleanser, it may be not completely cleaned out by washing it in the pure water. Moreover, if the cleanser remaining in slots or the like for loading the wafer are not completely removed by wahing in the water, and proceeds further to a next fabrication stage, for example a drying stage, a part of the cleaning product could be spreaded out by the centrifugal force arising from the rotation of the drier, thereby speckling the surfaces of the wafers. Hence, the surfaces of the wafers could be fatally contaminated, finally reducing the yield rate in the fabrication of the semiconductor devices. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to solve the above problem. 
     It is another object of the present invention to provide a wafer cleansing device for use in the manufacture of semiconductor devices, wherein each separate carrier for wafers is used for each of a plurality of cleaning processes in the fabrication stages of the semiconductor devices. 
     It is still another object of the present invention to provide a wafer cleaning device being capable of preventing the cleaning products used from mixing with each other, thereby increasing the cleaning effect of the wafers. 
     According to the present invention, each of the steps of the cleaning process uses a separate carrier rather than a single integrated carrier of wafers throughout the process, so that only the wafers to be processed may be washed, thus eliminating the necessity of cleaning the carrier, thereby saving the entire cleaning time in the process. Furthermore, during a drying process, the surfaces of the wafers are kept from being contaminated by the remaining cleaning products, consequently increasing the yield rate in the manufacture of the entire semiconductor devices. 
    
    
     BRIEF DESCRIPTION OF THE ATTACHED DRAWING 
     FIG. 1 is a schematic diagram of the inventive cleaning device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described in more detail with reference to the drawing attached only by way of example. 
     A plurality of cleaning baths 2,3,4,5,6 for cleaning a wafer 1 therein are disposed in series with a fixed interval of each other. A conveyor 21 disposed in the vicinity of a first cleaning bath 2 conveys the wafer 1 into the first cleaning bath 2 by using a carrier 14 of a hoisting and rotating arm 7. A plurality of hoisting and rotating arms 7-13 including each carrier in the ending part thereof are each arranged serially between any two of the conveying means, the cleaning baths 2-6 and a wafer drying means 22. The drying means 22 dries the wafer 1 received from the fifth cleaning bath 6, and has a hoist 23 for pushing the dried wafer 1. A plurality of separate carriers 14-20 are respectively attached to each of the hoisting and rotating arms for carrying the wafer 1 successively from the conveyor 21 to the drier through the series of said cleaning baths. A reference numeral 24 in the drawing is a cradle in the carrier operated to grasp the wafer. 
     The wafer 1 conveyed on the conveyer 21 to be processed during the cleaning stage is pushed up by hoist 25. Then, the hoisting and rotating arm 7 is slightly lowered from the uppermost position to load the wafer 1 in the carrier 14, which is closed by contracting the cradle 24. Thereafter, the hoist 25 is lowered to return to the original position, and arm 7 is rotated by a 180° direction from the initial one, so that the first carrier 14 can be positioned over the second carrier 15, where the cradle 24 is opened to move the wafer from the first carrier 14 to the second carrier 15. Thus, the wafer received in the second carrier 15 has been cleaned in the first cleaning bath 2 having a cleanser. 
     After cleaning the wafer in the cleaning bath 2 of cleanser, the second arm 8 is raised and rotated by 180°, so that the second carrier 15 can be positioned over the third carrier 16 attached to the third arm in the second cleaning bath 3. Then, the wafer 1 is moved from the second carrier into the third carrier 16, where the cleanser possible remaining on said wafer can be removed in pure water. After washing the wafer 1 with the water in the second cleaning bath 3, the wafer 1 is again cleaned by a cleanser in the third cleaning bath. The wafer cleaned by the cleanser is then washed with water in the fourth cleaning bath. Finally, the wafer will be completely cleaned with the water in the fifth cleaning bath 6 and is then moved into the drying means 22. The procedure of moving the wafer 1 is the same as the aforementioned and, therefore, will be not explained again here. 
     The wafer moved into the drying means 22 is completely rid of the remaining water by the centrifugal force thereon arising from the rotation of the dryer 22. Then, the dried wafer is raised upward by the hoisting means 23, and is moved into the carrier attached to the seventh arm 13 so as to be subjected to any subsequent process. 
     As described above, the cleaning device of the present invention uses a separate carrier in each cleaning bath, so that the various cleansers used in the different cleaning baths can not be mixed with each other. Moreover, since only the wafer is washed with pure water, the time for washing with pure water is reduced as well as the consumption of pure water. Also, the carrier used in drying is not used in the cleaning baths of cleansers, so that the wafer is not contaminated by the remaining cleanser when drying, thereby increasing the yield rate of semiconductor manufacturing. 
     The foregoing description shows only a preferred embodiment of the present invention. Various modifications are apparent to those skilled in the art without departing from the scope of the present invention which is only limited by the appended claims. Therefore, the embodiment shown and described is only intended to be illustrative, not restrictive.