Method and apparatus for cleaning and drying semiconductor wafer

Abstract

Provided is an apparatus and method for cleaning and drying a semiconductor wafer. Isopropyl alcohol and deionized water are premixed in a desired ratio before a cleaning solution containing isopropyl alcohol and deionized water is supplied into a treating bath. Accordingly, a chemical compound remaining due to deionized water can be effectively removed and the creation of water marks due to isopropyl alcohol can be effectively prevented. As a result, cleaning and drying effects can be increased and a cleaning solution can be reused.

What is claimed is:  
     
         1 . An apparatus for cleaning and drying a semiconductor wafer, the apparatus comprising: 
 a treating bath supplied with a cleaning solution from an external source and in which the semiconductor wafer is cleaned and dried;    a cleaning solution mixing unit wherein cleaning solutions to be supplied into the treating bath are mixed in a predetermined ratio and including isopropyl alcohol tanks that are supplied with isopropyl alcohol from an external source, mixing tanks that are supplied with deionized water from an external source, are connected to the isopropyl alcohol tanks to be supplied with isopropyl alcohol contained in the isopropyl alcohol tanks and mix isopropyl alcohol and deionized water, and level sensing means that sense the amount of isopropyl alcohol supplied into the IPA tanks and the amount of deionized water supplied into the mixing tanks;    a cleaning solution supplying unit that connects the mixing tanks to the treating bath and supplies the cleaning solution mixed in the mixing tanks into the treating bath; and    a return line through which the cleaning solution that was used in the cleaning of the semiconductor wafer is returned back to the mixing tanks.    
     
     
         2 . The apparatus of  claim 1 , wherein two or more isopropyl alcohol tanks of the cleaning solution mixing unit are interconnected in parallel, the mixing tanks are connected to the isopropyl alcohol tanks, respectively, and disposed in parallel so that each of the isopropyl alcohol tanks and each of the mixing tanks make a group, and the cleaning solution circulates through a mixing tank in a group selected from two or more groups.  
     
     
         3 . The apparatus of  claim 1  or  2 , wherein the level sensing means are a plurality of level sensors that are installed at the isopropyl alcohol tanks and a plurality of level sensors that are installed at the mixing tanks.  
     
     
         4 . The apparatus of  claim 1  or  2 , wherein the cleaning solution mixing unit further comprises a nitrogen bubble generator that injects a nitrogen gas into the mixing tanks so as to completely mix deionized water and isopropyl alcohol.  
     
     
         5 . The apparatus of  claim 1  or  2 , wherein isopropyl alcohol supplementing pumps that additionally supply isopropyl alcohol in the isopropyl alcohol tanks into the mixing tanks by a desired amount are further installed between the isopropyl alcohol tanks and the mixing tanks.  
     
     
         6 . The apparatus of  claim 1  or  2 , wherein the cleaning solution supplying unit comprises: 
 a circulating pump that pumps the cleaning solution in the mixing tanks into the treating bath;  
 a filter that filters the cleaning solution flowing via the circulating pump off impurities;  
 an isopropyl alcohol concentration measurer that checks the concentration of isopropyl alcohol contained in the cleaning solution that has passed through the filter; and  
 a liquid particle counter that detects the amount of liquid particle contained in the cleaning solution flowing into the treating bath.  
 
     
     
         7 . The apparatus of  claim 1  or  2 , wherein the return line comprises a liquid particle counter that detects liquid particle contained in the cleaning solution returning from the treating bath back to the mixing tanks.  
     
     
         8 . The apparatus of  claim 1  or  2 , further comprising: 
 a heating tank that is connected to the cleaning solution mixing unit, is supplied the cleaning solution from the mixing tanks, and heats the cleaning solution, and evaporates isopropyl alcohol from the cleaning solution using a difference between boiling points of isopropyl alcohol and deionized water to decompose the cleaning solution into pure isopropyl alcohol and deionized water;  
 an isopropyl alcohol filter that is connected to the heating tank and filters vapor isopropyl alcohol off impurities;  
 an isopropyl alcohol collecting tank that is supplied with isopropyl alcohol filtered through the isopropyl alcohol filter and condenses isopropyl alcohol;  
 a deionized water filter that is connected to the heating tank and passes deionized water remaining in the heating tank to filter impurities of deionized water; and  
 a deionized water collecting tank that is supplied with deionized water filtered through the deionized water filter and temporarily stores deionized water.  
 
     
     
         9 . The apparatus of  claim 1  or  2 , wherein a sink that is supplied with deionized water from an external source and sinks a lower portion of the treating bath under deionized water is further installed beneath the treating bath, wherein the sink includes an ultrasonic generator that generates ultrasonic waves, passes the ultrasonic waves through deionized water and the treating bath to the semiconductor wafer that is being cleaned in the treating bath.  
     
     
         10 . A method of cleaning and drying a wafer, the method comprising: 
 (a) mixing deionized water and isopropyl alcohol to make a cleaning solution;    (b) supplying the cleaning solution into a treating bath so that the cleaning solution contacts the semiconductor wafer in the treating bath to clean the semiconductor wafer;    (c) after the semiconductor wafer is cleaned, separating the semiconductor wafer from the cleaning solution;    (d) drying the semiconductor wafer separated from the cleaning solution to remove the cleaning solution remaining on the semiconductor wafer.    
     
     
         11 . The method of  claim 10 , wherein in step (b), before the cleaning solution is supplied into the treating bath, the semiconductor wafer is put into the treating bath.  
     
     
         12 . The method of  claim 10 , wherein in step (b), after the supply of the cleaning solution into the cleaning bath is completed, the semiconductor wafer is dipped into the cleaning solution.  
     
     
         13 . The method of  claim 10 , wherein in step (c), the semiconductor wafer is lifted up from the treating bath so that the semiconductor wafer is separated from the cleaning solution.  
     
     
         14 . The method of  claim 10 , wherein in step (c), the cleaning solution is discharged from the treating bath so that the semiconductor wafer is separated from the cleaning solution.  
     
     
         15 . The method of  claim 10 , wherein in step (a), the concentration of isopropyl alcohol in the cleaning solution varies according to time to adjust the concentration of isopropyl alcohol to a target concentration.  
     
     
         16 . The method of  claim 10 , wherein in step (d), a hot nitrogen gas is sprayed on the surface of the semiconductor wafer, contacts, and dries the surface of the semiconductor wafer.