Patent ID: 8136477
Filing Date: 2012-03-20
Classification: B05C,G03F,H01L

Abstract:
1. Apparatus for dispensing a chemical solution, comprising: a canister configured to receive a bottle containing chemical solution; a source of gas; gas supply piping extending between and connecting the canister and the source of gas and through which gas from the source can flow into the canister, whereby the interior of the canister is pressurized by the gas; a pressure control valve disposed in the gas supply piping and movable in increments between open and closed positions to control the pressure of the gas flowing through the gas supply piping; a trap comprising a tank; a first chemical supply line extending from the canister to the tank and through which chemical solution from a bottle received by the canister can flow into the tank; a nozzle from which the chemical solution is dispensed by the apparatus; a second chemical supply line extending between and connecting the tank and the nozzle and through which chemical solution can flow to the nozzle from the tank; a pressure sensor disposed in-line in the apparatus between the canister and the nozzle so as to sense the pressure of the chemical solution that has left the canister, and operative to output a signal representative of the pressure; and a controller operatively connected to the pressure sensor to receive the signal from the pressure sensor representative of the pressure of the chemical solution, the controller being configured to compare a value of the signal with values representative of a predetermined pressure range, and the controller being operatively connected to the pressure control valve so as to control the pressure control valve to move toward the open position thereof when the value of the signal output by the pressure sensor is less than a value representative of the minimum of the predetermined pressure range and so as to control the pressure control valve to move toward the closed position thereof when the value of the signal output by the pressure sensor is greater than a value representative of the maximum of the predetermined pressure range, whereby the degree to which the pressure control valve is open is controlled by feedback from the pressure control sensor such that the pressure of the chemical solution remains substantially constant as it is dispensed from the nozzle, wherein the pressure sensor is disposed in the first chemical supply line.