Substrate cleaning method, cleaning solution, cleaning apparatus and semiconductor device

Abstract

Disclosed is a substrate cleaning method for removing particles from a substrate includes a first step of adjusting the concentration of dissolved nitrogen in pure water, so as to be less than or equal to the concentration of dissolved nitrogen in equilibrium with the atmosphere (about 16 ppm), in a supply line that supplies the pure water, and a second step of cleaning a substrate by supplying a cleaning tank with a cleaning solution produced by mixing at least hydrogen peroxide with the pure water adjusted at the first step, and applying an ultrasonic wave to the cleaning solution in which the substrate is immersed.

What is claimed is:  
     
         1 . A method of cleaning a substrate comprising: 
 a first step of adjusting concentration of dissolved nitrogen in pure water, so as to be less than or equal to concentration of dissolved nitrogen in equilibrium with an atmosphere, in a pure-water supply line that supplies the pure water; and    a second step of supplying a cleaning tank with a cleaning solution produced by mixing at least hydrogen peroxide with the pure water having the concentration of dissolved nitrogen adjusted at the first step, and applying an ultrasonic wave to the cleaning solution in which a substrate is immersed to perform cleaning of the substrate.    
     
     
         2 . A method of cleaning a substrate comprising: 
 a first step of adjusting concentration of dissolved nitrogen in pure water, so as to be less than or equal to concentration of dissolved nitrogen in equilibrium with the atmosphere, in a pure-water supply line that supplies the pure water; and    a second step of supplying a cleaning tank with a cleaning solution produced by mixing hydrogen peroxide and ammonia with the pure water having the concentration of dissolved nitrogen adjusted at the first step, and applying an ultrasonic wave to the cleaning solution in which a substrate is immersed to perform cleaning of the substrate.    
     
     
         3 . The method according to  claim 1 , wherein said second step includes steps of: 
 inducing bubbling, by application of the ultrasonic wave, of at least the hydrogen peroxide dissolved in the cleaning solution; and    causing a bubble of the hydrogen peroxide to implode.    
     
     
         4 . The method according to  claim 1 , wherein the concentration of dissolved nitrogen in the pure water after the adjustment performed at said first step is 10 to 16 ppm.  
     
     
         5 . The method according to  claim 1 , wherein the first step includes steps of: 
 measuring the concentration of dissolved nitrogen in the pure water delivered through the pure-water supply line that supplies the pure water; and    adjusting amount of degassing the pure water based upon information relating to the measured concentration of the dissolved nitrogen.    
     
     
         6 . The method according to  claim 2 , wherein said second step includes steps of: 
 inducing bubbling, by application of the ultrasonic wave, of at least the hydrogen peroxide dissolved in the cleaning solution; and    causing a bubble of the hydrogen peroxide to implode.    
     
     
         7 . The method according to  claim 2 , wherein the concentration of dissolved nitrogen in the pure water after the adjustment performed at said first step is 10 to 16 ppm.  
     
     
         8 . The method according to  claim 2 , wherein the first step includes steps of: 
 measuring the concentration of dissolved nitrogen in the pure water delivered through the pure-water supply line that supplies the pure water; and    adjusting amount of degassing the pure water based upon information relating to the measured concentration of the dissolved nitrogen.    
     
     
         9 . A cleaning solution comprising pure water and hydrogen peroxide; 
 concentration of dissolved nitrogen in the pure water being adjusted so as to be less than or equal to concentration of dissolved nitrogen in equilibrium with the atmosphere.    
     
     
         10 . The cleaning solution according to  claim 9 , wherein the concentration of dissolved nitrogen in the pure water is 10 to 16 ppm.  
     
     
         11 . A cleaning apparatus comprising: 
 a cleaning tank for accommodating a cleaning solution for cleaning a substrate;    ultrasonics application means for applying an ultrasonic wave to the cleaning solution;    a mixer for producing the cleaning solution by mixing pure water and at least hydrogen peroxide, and for supplying the produced cleaning solution to said cleaning tank directly or after being adjusted in temperature;    a hydrogen-peroxide supply line for supplying said mixer with hydrogen peroxide;    a pure-water supply line for supplying said mixer with pure water;    a measurement unit for measuring concentration of dissolved nitrogen in the pure water delivered through said pure-water supply line;    a degassing unit for adjustably degassing the dissolved nitrogen in the pure water delivered through said pure-water supply line; and    a control unit for controlling the concentration of dissolved nitrogen in pure water using said degassing unit based upon information relating to the concentration of dissolved nitrogen measured by said measurement unit.    
     
     
         12 . A cleaning apparatus comprising: 
 a cleaning tank for accommodating a cleaning solution for cleaning a substrate;    ultrasonics application means for applying an ultrasonic wave to the cleaning solution;    a mixer for producing the cleaning solution by mixing pure water and at least hydrogen peroxide, and for supplying the produced cleaning solution to said cleaning tank directly or after being adjusted in temperature;    a hydrogen-peroxide supply line for supplying said mixer with hydrogen peroxide;    a pure-water supply line for supplying said mixer with pure water;    a mixer for producing the cleaning solution by mixing pure water, hydrogen peroxide and ammonia, and for supplying the produced cleaning solution to said cleaning tank directly or after being adjusted in temperature;    a hydrogen-peroxide supply line for supplying said mixer with hydrogen peroxide;    an ammonia supply line for supplying said mixer with ammonia;    a pure-water supply line for supplying said mixer with pure water;    a measurement unit for measuring concentration of dissolved nitrogen in the pure water delivered through said pure-water supply line;    a degassing unit for adjustably degassing the dissolved nitrogen in the pure water delivered through said pure-water supply line; and    a control unit for controlling the concentration of dissolved nitrogen in pure water using said degassing unit based upon information relating to the concentration of dissolved nitrogen measured by said measurement unit.    
     
     
         13 . The apparatus according to  claim 11 , wherein said measurement unit and said degassing unit are disposed in said pure-water supply line in close proximity to said mixer.  
     
     
         14 . The apparatus according to  claim 12 , wherein said measurement unit and said degassing unit are disposed in said pure-water supply line in close proximity to said mixer.  
     
     
         15 . A semiconductor substrate cleaned by a cleaning method comprising a first step of adjusting concentration of dissolved nitrogen in pure water, so as to be less than or equal to concentration of dissolved nitrogen in equilibrium with an atmosphere, in a pure-water supply line that supplies the pure water; and 
 a second step of supplying a cleaning tank with a cleaning solution produced by mixing at least hydrogen peroxide with the pure water having the concentration of dissolved nitrogen adjusted at the first step, and applying an ultrasonic wave to the cleaning solution in which the semiconductor substrate is immersed to perform cleaning of the semiconductor substrate.    
     
     
         16 . A semiconductor substrate cleaned by a cleaning method comprising a first step of adjusting concentration of dissolved nitrogen in pure water, so as to be less than or equal to concentration of dissolved nitrogen in equilibrium with the atmosphere, in a pure-water supply line that supplies the pure water; and 
 a second step of supplying a cleaning tank with a cleaning solution produced by mixing hydrogen peroxide and ammonia with the pure water having the concentration of dissolved nitrogen adjusted at the first step, and applying an ultrasonic wave to the cleaning solution in which the semiconductor substrate is immersed to perform cleaning of the semiconductor substrate.