United Microelectronics Corp.

Cha-Ming Kuo

Hung-Lung Ma

Hsien-Jung Hsu

Shih-Hsun Chiu

A photoresist dispensing system used in a photoresist coating machine includes a pump, a switch valve, a sucking-back valve, a solenoid valve, a first set of speed controllers a second set of speed controllers and a sucking-back speed controller. The pump is used to transport liquid photoresist to a wafer through the switch valve. The sucking-back valve is controlled by solenoid valve through the sucking-back speed controller to produce or release a sucking force on the liquid photoresist to prevent it from undesired dropping onto the wafer. The solenoid valve also controls the switch valve and the pump to start or stop photoresist dispensing. The first set of speed controllers is coupled between the switch valve and the solenoid valve and the second set of speed controller is coupled between the pump and the solenoid valve. The sucking-back speed controller is coupled between the sucking-back valve and the route, which is between the first set of speed controller and the switch valve so that the sucking-back valve has a sufficient delay time to effectively suck the liquid photoresist in a proper time order of operation.

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Chi-Lung, Taiwan

Cha-Ming Kuo