Method and apparatus for continuously blending chemical solutions

Abstract

Provided are a method and apparatus for continuously blending a chemical solution for use in semiconductor processing. The method involves the step of: mixing a first chemical stream with a second chemical stream in a controlled manner, to form a stream of a solution having a predetermined formulation. The apparatus allows one to practice the above method. The method and apparatus can accurately provide chemical solutions of desired concentration in a continuous manner. The invention has particular applicability in semiconductor device fabrication.

1 . A method of continuously blending a chemical solution for use in semiconductor processing, comprising: 
 mixing a first chemical stream with a second chemical stream in a controlled manner, to form a stream of a solution having a predetermined formulation.    
   
   
       2 . The method according to  claim 1 , wherein a flowrate of the first chemical or the second chemical is controlled in response to a signal generated by a sensor which monitors the solution.  
   
   
       3 . The method according to  claim 2 , wherein the sensor is selected from the group consisting of conductivity and acoustic signature sensors.  
   
   
       4 . The method according to  claim 3 , wherein the solution is ionic, and the sensor is a conductivity sensor.  
   
   
       5 . The method according to  claim 4 , wherein the conductivity sensor is an electrodeless conductivity sensor employing AC toroid coils.  
   
   
       6 . The method according to  claim 3 , wherein the solution is non-ionic, and the sensor is an acoustic signature sensor.  
   
   
       7 . The method according to  claim 1 , wherein the first chemical or the second chemical is deionized water.  
   
   
       8 . The method according to  claim 1 , wherein the first and second chemicals are generated on-site.  
   
   
       9 . A method of continuously blending a chemical solution for use in semiconductor processing, comprising the steps of: 
 (a) mixing a first chemical with a second chemical in a controlled manner to provide a first solution having a predetermined formulation; and    (b) mixing a third chemical with the first solution in a controlled manner to provide a second solution having a predetermined formulation,    wherein steps (a) and (b) are performed contemporaneously.    
   
   
       10 . The method according to  claim 9 , wherein step (a), the flowrate of the first chemical or the second chemical is controlled in response to a signal generated by a first sensor which monitors the first solution, and in step (b), the flowrate of the third chemical or the first solution is controlled in response to a signal generated by a second sensor which monitors the second solution.  
   
   
       11 . The method according to  claim 10 , wherein the first sensor and the second sensor are of the same or different types, and are selected from the group consisting of conductivity sensors and acoustic signature sensors.  
   
   
       12 . The method according to  claim 11 , wherein the first sensor and/or the second sensor is an AC toroid coil sensor.  
   
   
       13 . The method according to  claim 11 , wherein the first solution and the second solution are ionic solutions, and the first sensor and the second sensor are conductivity sensors.  
   
   
       14 . The method according to  claim 13 , wherein the conductivity sensor is an electrodeless conductivity sensor employing AC toroid coils.  
   
   
       15 . The method according to  claim 11 , wherein one of the first solution and the second solution is a non-ionic solution and the other of the first solution and the second solution is an ionic solution.  
   
   
       16 . The method according to  claim 9 , wherein the first chemical or the second chemical is deionized water.  
   
   
       17 . The method according to  claim 9 , further comprising: 
 (c) mixing a fourth chemical with the second solution in a controlled manner to provide a third solution having a predetermined formulation,    wherein step (c) is performed contemporaneously with steps (a) and (b).    
   
   
       18 . A method of continuously blending a chemical solution on-site at a semiconductor manufacturing facility, comprising the steps of: 
 (a) mixing a first chemical with a second chemical in a controlled manner to provide a first solution having a predetermined formulation; and    (b) mixing a third chemical with the first solution in a controlled manner to provide a second solution having a predetermined formulation; and    (c) introducing the blended solution into a semiconductor processing tool,    wherein steps (a) and (b) are performed contemporaneously.    
   
   
       19 . The method according to  claim 18 , further comprising between steps (b) and (c), a step (b′) of mixing a fourth chemical with the second solution in a controlled manner to provide a third solution having a predetermined formulation, wherein step (b′) is performed contemporaneously with steps (a) and (b).  
   
   
       20 . An apparatus for continuously blending a chemical solution for use in semiconductor processing, comprising: 
 a first chemical source and a second chemical source connected by a conduit system to allow a stream of the first chemical to be mixed with a stream of the second chemical to form a solution; and    means for controlling the formulation of the solution.    
   
   
       21 . The apparatus according to  claim 20 , wherein the first chemical and the second chemical are mixed in a first mixing zone.  
   
   
       22 . The apparatus according to  claim 20 , wherein the controlling means comprises a sensor which monitors the solution.  
   
   
       23 . The apparatus according to  claim 20 , wherein the sensor is selected from the group consisting of conductivity and acoustic signature sensors.  
   
   
       24 . The apparatus according to  claim 23 , wherein the solution is an ionic solution, and the sensor is a conductivity sensor.  
   
   
       25 . The apparatus according to  claim 24 , wherein the conductivity sensor is an electrodeless conductivity sensor employing AC toroid coils.  
   
   
       26 . The apparatus according to  claim 24 , wherein the solution is non-ionic, and the sensor is an acoustic signature sensor.  
   
   
       27 . The apparatus according to  claim 20 , wherein the first chemical or the second chemical is deionized water.  
   
   
       28 . An apparatus for continuously blending a chemical solution for use in semiconductor processing, comprising: 
 a first chemical source, a second chemical source and a third chemical source connected by a conduit system to allow a stream of the first chemical to be mixed with a stream of the second chemical to form a first solution, and a stream of the first solution to be mixed with a stream of the third chemical to provide a second solution, wherein the first and second solutions are provided contemporaneously; and    means for controlling the formulations of the first and second solutions.    
   
   
       29 . The apparatus according to  claim 28 , wherein the first chemical and the second chemical are mixed in a first mixing zone, and the first solution stream and the third chemical are mixed in a second mixing zone downstream of the first mixing zone.  
   
   
       30 . The apparatus according to  claim 28 , wherein the controlling means comprises a first sensor which monitors the first solution and a second sensor which monitors the second solution.  
   
   
       31 . The apparatus according to  claim 30 , wherein the first sensor and the second sensor are of the same or different types, and are selected from the group consisting of conductivity sensors and acoustic signature sensors.  
   
   
       32 . The apparatus according to  claim 31 , wherein the first sensor and/or the second sensor is an AC toroid coil sensor.  
   
   
       33 . The apparatus according to  claim 32 , wherein the first solution and the second solution are ionic solutions, and the first sensor and the second sensor are conductivity sensors.  
   
   
       34 . The apparatus according to  claim 33 , wherein the conductivity sensors are electrodeless conductivity sensors employing AC toroid coils.  
   
   
       35 . The apparatus according to  claim 33 , wherein one of the first solution and the second solution is a non-ionic solution and the other of the first solution and the second solution is an ionic solution.  
   
   
       36 . The apparatus according to  claim 28 , wherein the first chemical or the second chemical is deionized water.  
   
   
       37 . The apparatus according to  claim 28 , further comprising: 
 a fourth chemical source connected by the conduit system to allow a stream of the fourth chemical to be mixed with a stream of the second solution to form a third solution, wherein the third solution is provided contemporaneously with the first and second solutions, and wherein the means for controlling further controls the formulation of the third solution.    
   
   
       38 . An apparatus for continuously blending a chemical solution on-site at a semiconductor manufacturing facility, comprising: 
 a first chemical source, a second chemical source and a third chemical source connected by a conduit system to allow a stream of the first chemical to be mixed with a stream of the second chemical to form a first solution, and a stream of the first solution to be mixed with a stream of the third chemical to provide a second solution, wherein the first and second solutions are provided contemporaneously;    means for controlling the formulations of the first and second solutions; and    a semiconductor processing tool connected to receive the blended solution.    
   
   
       39 . The apparatus according to  claim 38 , further comprising: 
 at least one additional chemical source connected by the conduit system to allow a stream of said at least one additional chemical to be mixed with a stream of the second solution to form at least one additional solution, wherein said at least one additional solution is provided contemporaneously with the first and second solutions, and wherein the means for controlling further controls the formulation of the at least one additional solution.