Chemical Supply System

Abstract

A chemical supply system comprises, as principal elements, a chemical storage tank in which a liquid chemical for cleaning is stored in the state of its formulated concentrate, a chemical supply apparatus connected to the chemical storage tank for positively performing chemical supply, a piping system connected to the chemical supply apparatus to form a supply flow passage that is a passage for ultrapure water which the liquid chemical is to be mixed with, a pair of discharge nozzles disposed at end portions of the piping system so as to oppose surfaces of a wafer set in a cleaning chamber to supply a cleaning liquid onto the surfaces. Thereby, remarkable miniaturization/simplification of a cleaning liquid supply system including chemical tanks is intended, it is made possible easily and rapidly to compound and supply a cleaning liquid at an accurate chemical concentration, and particles or the like being generated and mixing in a cleaning liquid, are suppressed to the extremity.

1 . A chemical supply apparatus comprising:
 a chemical supply pump, and   a connecting flow passage connecting a supply flow passage that is a passage for a solvent with which said liquid chemical is mixed, and said chemical supply pump,   wherein a tubule member directly connecting said supply flow passage is provided in said connecting flow passage, and,   in said chemical supply pump,   a flow passage for passing a predetermined liquid chemical is formed, a suction valve which is closed by pressure rise of said liquid chemical is provided at a flowing-in port of said flow passage, and a discharge valve which is closed by pressure fall of said liquid chemical is provided at a flowing-out port of said flow passage,   at least part of a liquid contact surface in said flow passage is made of a compact member with non-permeability and a high anti-corrosion property to said liquid chemical, and part of said compact member is made into a movable wall,   a shaker connected to said movable wall is provided, and said movable wall is oscillated in a direction substantially perpendicular to its wall surface by drive of said shaker to change the volume of said flow passage periodically, and,   by drive of said chemical supply pump, said liquid chemical is discharged from said tubule member into said solvent passing through said supply flow passage to compound a mixture solution at a desired concentration.   
   
   
       2 . A chemical supply apparatus as claimed in  claim 1 , wherein the discharge direction of said liquid chemical is a direction substantially perpendicular to the flow direction of said solvent, and
 said chemical supply pump gives said liquid chemical a pressure such that the linear velocity of said liquid chemical discharged from said tubule member is greater than the linear velocity of said solvent passing through said supply flow passage.   
   
   
       3 . A chemical supply apparatus as claimed in  claim 1 , wherein an electrode surrounding part of said connecting flow passage is provided, and the electrostatic capacity of said liquid chemical passing through said connecting flow passage is measured by said electrode. 
   
   
       4 . A chemical supply apparatus as claimed in  claim 1 , comprising a chemical discharge stop means surrounding part of said connecting flow passage near said tubule member, said chemical discharge stop means operating so as to suck some quantity of said solvent in said supply flow passage from said tubule member synchronously with stoppage of said chemical supply pump. 
   
   
       5 . A chemical supply apparatus as claimed in  claim 4 , wherein said chemical discharge stop means has an electric heating system for heating said liquid chemical to a predetermined temperature, and heating by said electric heating system is stopped synchronously with stoppage of said chemical supply pump. 
   
   
       6 . A chemical supply apparatus as claimed in  claim 4 , wherein said chemical discharge stop means has a compression system, and drives synchronously with stoppage of said chemical supply pump. 
   
   
       7 . A chemical supply apparatus as claimed in  claim 1 , comprising a chemical discharge stop means which is directly connected to part of said connecting flow passage near said tubule member, and comprises another tubule member connected to a portion corresponding to the upstream of said solvent of the connection portion of said tubule member of said supply flow passage,
 said chemical discharge stop means operating so as to supply said solvent from said other tubule member into said supply flow passage synchronously with stoppage of said chemical supply pump, and to push out said liquid chemical remaining in said connecting flow passage to said supply flow passage side by an action of a check valve provided on said chemical supply pump side.   
   
   
       8 . A chemical supply apparatus as claimed in  claim 7 , wherein a check valve is provided near an inlet of said other tubule member, and the concentration change of said liquid chemical is minimized. 
   
   
       9 . A chemical supply apparatus as claimed in  claim 1 , wherein said tubule member has an electric heating system for heating said liquid chemical to a predetermined temperature, and heating by said electric heating system is stopped synchronously with stoppage of said chemical supply pump to suck some quantity of said solvent in said supply flow passage. 
   
   
       10 . A chemical supply apparatus as claimed in  claim 1 , wherein a pair of temperature detection elements is embedded near the connection portion to said supply flow passage of said tubule member, and 
     the temperature difference between said temperature detection elements is detected synchronously with said chemical supply pump, and the flow condition of said mixture solution is monitored. 
   
   
       11 . A chemical supply apparatus as claimed in  claim 1 , wherein said solvent is ultrapure water. 
   
   
       12 . A chemical supply apparatus as claimed in  claim 1 , wherein said tubule member is conductive. 
   
   
       13 . A chemical supply apparatus as claimed in  claim 12 , wherein said tubule member is made of amorphous carbon. 
   
   
       14 . A chemical supply system comprising:
 at least one kind of easily moveable chemical reservoir,   a chemical supply apparatus connected in correspondence to said chemical reservoir, and   said supply flow passage,   said chemical supply apparatus comprising:
 a chemical supply pump, and 
 a connecting flow passage connecting the supply flow passage that is a passage for a solvent with which said liquid chemical is mixed, and said chemical supply pump, 
 wherein a tubule member directly connected to said supply flow passage is provided in said connecting flow passage, and, 
   in said chemical supply pump,
 a flow passage for passing a predetermined liquid chemical is formed, a suction valve which is closed by pressure rise of said liquid chemical is provided at a flowing-in port of said flow passage, and a discharge valve which is closed by pressure fall of said liquid chemical is provided at a flowing-out port of said flow passage, 
 at least part of a liquid contact surface in said flow passage is made of a compact member with non-permeability and a high anti-corrosion property to said liquid chemical, and part of said compact member is made into a movable wall, and 
 a shaker connected to said movable wall is provided, and said movable wall is oscillated in a direction substantially perpendicular to its wall surface by drive of said shaker to change the volume of said flow passage periodically, 
 said chemical supply apparatus discharging said liquid chemical from said tubule member into said solvent passing through said supply flow passage by drive of said chemical supply pump to compound a mixture solution at a desired concentration, 
 said chemical supply system being characterized by discharging said mixture solution made into the predetermined concentration from a discharge portion provided at an end portion of said supply flow passage, by drive of said chemical supply pump of said chemical supply apparatus. 
   
   
   
       15 . A chemical supply system as claimed in  claim 14 , comprising a control system for regulating said mixture solution supplied from said discharge portion. 
   
   
       16 . A chemical supply system described in  claim 15 , comprising:
 a flow rate regulation means for regulating the flow rate of said solvent or said liquid chemical passing through said supply flow passage, and   a concentration regulation means for regulating the concentration of said mixture solution passing through said supply flow passage,   wherein said control system has a chemical supply control means for regulating the supply quantity of said liquid chemical to said solvent of said chemical supply pump, and a concentration control means for driving said concentration regulation means,   said chemical supply control means drives said flow rate regulation means,   said chemical supply control means and said concentration control means are connected, and a result of concentration control by said concentration control means is fed back to said chemical supply control means to regulate the supply quantity of said liquid chemical.   
   
   
       17 . A chemical supply system as claimed in  claim 14 , comprising a mixing means for producing a rotational flow in said mixture solution to stir and uniformize said mixture solution,
 wherein said mixing means has a spiral pitch in a flow passage for said mixture solution, and a rotational flow is produced by said mixture solution passing through said pitch.   
   
   
       18 . A chemical supply system as claimed in  claim 14 , comprising a mixing means for producing a rotational flow in said mixture solution to stir and uniformize said mixture solution, wherein, in said mixing means, a flowing-in portion to said mixing means in said supply flow passage and a flowing-out portion are provided to be slightly offset. 
   
   
       19 . A chemical supply system as claimed in  claim 14 , characterized in that said chemical reservoir is constructed by having a main reservoir in which a sufficient quantity of said liquid chemical is stored, and an auxiliary reservoir which is connected to said main reservoir and only a necessary quantity of said liquid chemical is supplied to from said main reservoir, and
 said auxiliary reservoir has a liquid surface level regulation means for regulating the liquid surface level of said liquid chemical supplied to control said chemical quantity.   
   
   
       20 . A chemical supply system as claimed in  claim 19 , wherein said liquid surface level regulation means is a pair of bar-like sensors made of conductive members, and calculates said liquid surface level and the changing speed thereof by measuring the electrostatic capacity of the dipped portions of said bar-like sensors in the liquid chemical and its change over time. 
   
   
       21 . A chemical supply system as claimed in  claim 14 , wherein said supply flow passage has a connecting tube branching from a portion corresponding to the upstream of said solvent of the connection portion to said tubule member, said connecting tube is connected to said chemical supply pump to form a closed system, and,
 when said chemical reservoir is unused, said solvent is made to flow in said closed system to defoam.   
   
   
       22 . A chemical supply system as claimed in  claim 14 , wherein a plurality of said chemical supply apparatus is connected to said chemical reservoirs in correspondence to a plurality of said chemical reservoirs in each of which a predetermined: Liquid chemical is stored, and
 said chemical supply apparatus are arbitrarily driven to mix said liquid chemicals with said solvent passing through said supply flow passage, in a desired order.   
   
   
       23 . A chemical supply system as claimed in  claim 14 , wherein a degassing tube whose surface layer is a degassing film is provided between said chemical reservoir and said chemical supply pump, said liquid chemical is passed through said degassing tube in a state that the external temperature pressure of said degassing tube is low, and degassing of said liquid chemical is performed.