Gas dissolved water producing apparatus and method thereof and ultrasonic cleaning equipment and method thereof

Abstract

A gas dissolved water producing apparatus includes a gas dissolving section, a gas channel for guiding a gas into the dissolving section, a first water channel for guiding water into the dissolving section, a gas dissolved water discharge channel, and a second water channel for guiding the water without passing through the dissolving section. The second water channel joins the gas dissolved water discharge channel to control the solution gas dissolved in the gas dissolved water can be controlled to a prescribed level of concentration.

1 . A polishing method comprising:
 polishing a semiconductor wafer so as to form a polished surface on the semiconductor wafer;   after said polishing, orienting the semiconductor wafer so that the polished surface of the semiconductor wafer faces upwards;   rotating the semiconductor wafer;   ejecting cleaning liquid against the polished surface of the semiconductor wafer so as to wash off debris from the polished surface of the semiconductor wafer, the cleaning liquid being gas-dissolved water having a solution gas dissolved therein such that a solution gas concentration is no greater than a saturated solution gas concentration;   controlling the solution gas concentration of the gas-dissolved water by adjusting a flow rate of water to be treated with the solution gas to form the gas-dissolved water; and   applying ultrasonic energy to the gas-dissolved water.   
   
   
       2 . The polishing method of  claim 1 , wherein a flow of the cleaning liquid is controlled such that surfaces in contact with the cleaning liquid are made of a non-metal material. 
   
   
       3 . The polishing method of  claim 2 , wherein said applying of the ultrasonic energy to the gas-dissolved water is performed by an ultrasonic cleaning device;
 further comprising producing the gas-dissolved water in a gas-dissolved water producing apparatus, said producing of the gas-dissolved water comprising:
 guiding the solution gas into a dissolving section through a solution gas supply channel; 
 guiding water through a water supply channel, said guiding including:
 guiding a first portion of the water into the dissolving section through a first channel of the water supply channel; and 
 guiding a second portion of the water around the dissolving section through a second channel of the water supply channel so that the second portion of the water does not pass through the dissolving section; 
 
 dissolving a solution gas into the first portion of the water within the dissolving section to form the gas-dissolved water; and 
 guiding the gas-dissolved water from the dissolving section through a gas-dissolved water discharge channel, the second supply channel communicating with the gas-dissolved water discharge channel so that the second portion of the water that does not pass through the dissolving section flows into the gas-dissolved water to thereby dilute the gas-dissolved water; and 
   wherein said controlling of the solution gas concentration of the gas-dissolved water comprises:
 measuring the solution gas concentration of the gas-dissolved water in the gas-dissolved water discharge channel by using a dissolved solution gas concentration meter; 
 regulating a flow of the water guided through the first channel and the second channel of the water supply channel by a flow rate regulator arranged in the water supply channel; and 
 controlling the flow rate regulator based on the solution gas concentration measured by the dissolved solution gas concentration meter. 
   
   
   
       4 . The polishing method of  claim 3 , wherein said regulating the flow of the water guided through the first channel and the second channel comprises controlling a first flow regulator located in the gas-dissolved water discharge channel, and controlling a second flow regulator located in the second channel of the water supply channel so as to control an amount of the first portion of the water flowing through the dissolving section and an amount of the second portion of the water not passing through the dissolving section. 
   
   
       5 . The polishing method of  claim 2 , wherein said controlling of the solution gas concentration of the gas-dissolved water comprises:
 measuring the solution gas concentration of the gas-dissolved water; and   based on the measured solution gas concentration, controlling a flow of water to be formed into the cleaning liquid by regulating an amount of a first portion of the water passing through a dissolving section so as to be formed into the gas-dissolved water within the dissolving section, and by regulating an amount of a second portion of the water bypassing the dissolving section.   
   
   
       6 . The polishing method of  claim 5 , wherein said controlling of the solution gas concentration of the gas-dissolved water further comprises adding the second portion of the water bypassing the dissolving section into the gas-dissolved water discharged from the dissolving section. 
   
   
       7 . The polishing method of  claim 1 , wherein said applying of the ultrasonic energy to the gas-dissolved water is performed by an ultrasonic cleaning device;
 further comprising producing the gas-dissolved water in a gas-dissolved water producing apparatus, said producing of the gas-dissolved water comprising:
 guiding the solution gas into a dissolving section through a solution gas supply channel; 
 guiding water through a water supply channel, said guiding including:
 guiding a first portion of the water into the dissolving section through a first channel of the water supply channel; and 
 guiding a second portion of the water around the dissolving section through a second channel of the water supply channel so that the second portion of the water does not pass through the dissolving section; 
 
 dissolving a solution gas into the first portion of the water within the dissolving section to form the gas-dissolved water; and 
 guiding the gas-dissolved water from the dissolving section through a gas-dissolved water discharge channel, the second supply channel communicating with the gas-dissolved water discharge channel so that the second portion of the water that does not pass through the dissolving section flows into the gas-dissolved water to thereby dilute the gas-dissolved water; and 
   wherein said controlling of the solution gas concentration of the gas-dissolved water comprises:
 measuring the solution gas concentration of the gas-dissolved water in the gas-dissolved water discharge channel by using a dissolved solution gas concentration meter; 
 regulating a flow of the water guided through the first channel and the second channel of the water supply channel by a flow rate regulator arranged in the water supply channel; and 
 controlling the flow rate regulator based on the solution gas concentration measured by the dissolved solution gas concentration meter. 
   
   
   
       8 . The polishing method of  claim 7 , wherein said regulating the flow of the water guided through the first channel and the second channel comprises controlling a first flow regulator located in the gas-dissolved water discharge channel, and controlling a second flow regulator located in the second channel of the water supply channel so as to control an amount of the first portion of the water flowing through the dissolving section and an amount of the second portion of the water not passing through the dissolving section. 
   
   
       9 . The polishing method of  claim 1 , wherein said controlling of the solution gas concentration of the gas-dissolved water comprises:
 measuring the solution gas concentration of the gas-dissolved water; and   based on the measured solution gas concentration, controlling a flow of water to be formed into the cleaning liquid by regulating an amount of a first portion of the water passing through a dissolving section so as to be formed into the gas-dissolved water within the dissolving section, and by regulating an amount of a second portion of the water bypassing the dissolving section.   
   
   
       10 . The polishing method of  claim 9 , wherein said controlling of the solution gas concentration of the gas-dissolved water further comprises adding the second portion of the water bypassing the dissolving section into the gas-dissolved water discharged from the dissolving section.