Semiconductor cleaner and method of cleaning semiconductor

Abstract

A semiconductor cleaner includes (a) an inner wet bath which is filled with liquid and in which a wafer to be cleaned is soaked, (b) an outer wet bath which is filled with liquid and in which the inner wet bath is soaked, (c) a megasonic-wave irradiator located outside the inner wet bath for irradiating megasonic waves to the wafer to clean the wafer, and (d) a unit which moves the megasonic-wave irradiator towards or away from the inner wet bath.

What is claimed is:  
     
         1 . A semiconductor cleaner comprising: 
 (a) a wet bath which is filled with liquid and in which a wafer to be cleaned is soaked;    (b) a megasonic-wave irradiator located outside said wet bath for irradiating megasonic waves to said wafer to clean said wafer; and    (c) a unit which moves said megasonic wave irradiator towards or away from said wet bath.    
     
     
         2 . The semiconductor cleaner as set forth in  claim 1 , wherein said unit moves said megasonic-wave irradiator by a distance in the range of 2 mm to 20 mm both inclusive.  
     
     
         3 . The semiconductor cleaner as set forth in  claim 1 , wherein said megasonic-wave irradiator irradiates megasonic waves having a frequency in the range of 750 KHz to 1 MHz both inclusive.  
     
     
         4 . The semiconductor cleaner as set forth in  claim 1 , wherein said wet bath is formed at an inner surface thereof with irregularity having a surface roughness greater than a wavelength of said megasonic waves.  
     
     
         5 . The semiconductor cleaner as set forth in  claim 1 , wherein said unit moves said megasonic-wave irradiator at a rate which is not equal to multiples of a phase velocity of said megasonic waves and multiples of a half of a phase velocity of said megasonic waves, and said unit moves said megasonic-wave irradiator by a distance which is not equal to multiples of a wavelength of said megasonic waves and multiples of a half of a wavelength of said megasonic waves.  
     
     
         6 . A semiconductor cleaner comprising: 
 (a) a wet bath which is filled with liquid and in which first to N-th wafers to be cleaned are soaked wherein N is an integer equal to or greater than two;    (b) first to N-th megasonic-wave irradiators located outside said wet bath and associated with said first to N-th wafers, respectively, for irradiating megasonic waves to said first to N-th wafers to clean said first to N-th wafers; and    (c) first to N-th units which move said first to N-th megasonic-wave irradiators towards or away from said wet bath, respectively.    
     
     
         7 . The semiconductor cleaner as set forth in  claim 6 , wherein said first to N-th units move said first to N-th megasonic-wave irradiators, respectively, by a distance in the range of 2 mm to 20 mm both inclusive.  
     
     
         8 . The semiconductor cleaner as set forth in  claim 6 , wherein said first to N-th megasonic-wave irradiators irradiate megasonic waves having a frequency in the range of 750 KHz to 1 MHz both inclusive.  
     
     
         9 . The semiconductor cleaner as set forth in  claim 6 , wherein said wet bath is formed at an inner surface thereof with irregularity having a surface roughness greater than a wavelength of said megasonic waves.  
     
     
         10 . The semiconductor cleaner as set forth in  claim 6 , wherein each of said first to N-th units moves said megasonic-wave irradiator at a rate which is not equal to multiples of a phase velocity of said megasonic waves and multiples of a half of a phase velocity of said megasonic waves, and each of said first to N-th units moves said megasonic-wave irradiator by a distance which is not equal to multiples of a wavelength of said megasonic waves and multiples of a half of a wavelength of said megasonic waves.  
     
     
         11 . A semiconductor cleaner comprising: 
 (a) a wet bath which is filled with liquid and in which a wafer to be cleaned is soaked; and    (b) a megasonic-wave irradiator located outside said wet bath for irradiating megasonic waves to said wafer to clean said wafer,    said wet bath being formed at an inner surface thereof with irregularity having a surface roughness greater than a wavelength of said megasonic waves.    
     
     
         12 . A semiconductor cleaner comprising: 
 (a) an inner wet bath which is filled with liquid and in which a wafer to be cleaned is soaked;    (b) an outer wet bath which is filled with liquid and in which said inner wet bath is soaked;    (c) a megasonic-wave irradiator located outside said inner wet bath for irradiating megasonic waves to said wafer to clean said wafer; and    (d) a unit which moves said megasonic-wave irradiator towards or away from said inner wet bath.    
     
     
         13 . The semiconductor cleaner as set forth in  claim 12 , wherein said megasonic-wave irradiator is comprised of: 
 (c1) a megasonic-wave oscillation plate located in said outer wet bath and below a bottom of said inner wet bath in parallel with said bottom of said inner wet bath; and    (c2) a megasonic-wave oscillator connected at one end to said megasonic-wave oscillation plate and at the other end to said unit, said megasonic-wave oscillator being fit into an opening formed at a bottom of said outer wet bath for slidable movement.    
     
     
         14 . The semiconductor cleaner as set forth in  claim 12 , wherein said inner wet bath is composed of quartz.  
     
     
         15 . The semiconductor cleaner as set forth in  claim 12 , wherein said unit moves said megasonic-wave irradiator by a distance in the range of 2 mm to 20 mm both inclusive.  
     
     
         16 . The semiconductor cleaner as set forth in  claim 12 , wherein said megasonic-wave irradiator irradiates megasonic waves having a frequency in the range of 750 KHz to 1 MHz both inclusive.  
     
     
         17 . The semiconductor cleaner as set forth in  claim 12 , wherein said inner wet bath is formed at an inner surface thereof with irregularity having a surface roughness greater than a wavelength of said megasonic waves.  
     
     
         18 . The semiconductor cleaner as set forth in  claim 12 , wherein said unit moves said megasonic-wave irradiator at a rate which is not equal to multiples of a phase velocity of said megasonic waves and multiples of a half of a phase velocity of said megasonic waves, and said unit moves said megasonic-wave irradiator by a distance which is not equal to multiples of a wavelength of said megasonic waves and multiples of a half of a wavelength of said megasonic waves.  
     
     
         19 . A semiconductor cleaner comprising: 
 (a) an inner wet bath which is filled with liquid and in which first to N-th wafers to be cleaned are soaked wherein N is an integer equal to or greater than two;    (b) an outer wet bath which is filled with liquid and in which said inner wet bath is soaked;    (c) first to N-th megasonic-wave irradiators located outside said inner wet bath and associated with said first to N-th wafers, respectively, for irradiating megasonic waves to said first to N-th wafers to clean said first to N-th wafers; and    (d) first to N-th units which move said first to N-th megasonic-wave irradiators towards or away from said inner wet bath, respectively.    
     
     
         20 . The semiconductor cleaner as set forth in  claim 19 , wherein each of said first to N-th megasonic-wave irradiators is comprised of: 
 (c1) a megasonic-wave oscillation plate located in said outer wet bath and below a bottom of said inner wet bath in parallel with said bottom of said inner wet bath; and    (c2) a megasonic-wave oscillator connected at one end to said megasonic-wave oscillation plate and at the other end to each of said first to N-th units, said megasonic-wave oscillator being fit into an opening formed at a bottom of said outer wet bath for slidable movement.    
     
     
         21 . The semiconductor cleaner as set forth in  claim 19 , wherein said inner wet bath is composed of quartz.  
     
     
         22 . The semiconductor cleaner as set forth in  claim 19 , wherein said first to N-th units move said first to N-th megasonic-wave irradiators, respectively, by a distance in the range of 2 mm to 20 mm both inclusive.  
     
     
         23 . The semiconductor cleaner as set forth in  claim 19 , wherein said first to N-th megasonic-wave irradiators irradiate megasonic waves having a frequency in the range of 750 KHz to 1 MHz both inclusive.  
     
     
         24 . The semiconductor cleaner as set forth in  claim 19 , wherein said wet bath is formed at an inner surface thereof with irregularity having a surface roughness greater than a wavelength of said megasonic waves.  
     
     
         25 . The semiconductor cleaner as set forth in  claim 19 , wherein each of said first to N-th units moves said megasonic-wave irradiator at a rate which is not equal to multiples of a phase velocity of said megasonic waves and multiples of a half of a phase velocity of said megasonic waves, and each of said first to N-th units moves said megasonic-wave irradiator by a distance which is not equal to multiples of a wavelength of said megasonic waves and multiples of a half of a wavelength of said megasonic waves.  
     
     
         26 . A semiconductor cleaner comprising: 
 (a) an inner wet bath which is filled with liquid and in which a wafer to be cleaned is soaked;    (b) an outer wet bath which is filled with liquid and in which said inner wet bath is soaked; and    (c) a megasonic-wave irradiator located outside said inner wet bath for irradiating megasonic waves to said wafer to clean said wafer;    said inner wet bath being formed at an inner surface thereof with irregularity having a surface roughness greater than a wavelength of said megasonic waves.    
     
     
         27 . A method of cleaning a wafer soaked in liquid filled in a wet bath, comprising the step of irradiating megasonic waves to said wafer with a relative distance between said wafer and a megasonic-wave irradiator being varied.  
     
     
         28 . The method as set forth in  claim 27 , wherein said relative distance is varied by reciprocating said megasonic-wave irradiator relative to said wafer.  
     
     
         29 . The method as set forth in  claim 27 , wherein said relative distance is varied in the range of 2 mm to 20 mm both inclusive.  
     
     
         30 . The method as set forth in  claim 27 , wherein said megasonic waves have a frequency in the range of 750 KHz to 1 MHz both inclusive.  
     
     
         31 . The method as set forth in  claim 27 , wherein relative distance is varied by moving said megasonic-wave irradiator at a rate which is not equal to multiples of a phase velocity of said megasonic waves and multiples of a half of a phase velocity of said megasonic waves, and by a distance which is not equal to multiples of a wavelength of said megasonic waves and multiples of a half of a wavelength of said megasonic waves.