초록 ▼

A system for dispensing liquid chemicals, such as photoresist, from containers which includes a valve to govern the flow from the containers, a reservoir to intermediately hold the chemicals prior to pumping, and a level detector to monitor the liquid in the reservoir and to control the valve, and a

A system for dispensing liquid chemicals, such as photoresist, from containers which includes a valve to govern the flow from the containers, a reservoir to intermediately hold the chemicals prior to pumping, and a level detector to monitor the liquid in the reservoir and to control the valve, and an aspirator to remove air from the reservoir. The aspirator is activated in response to signals from the level detector indicating that the reservoir level is low. The increased suction causes liquid to be drawn from the container into the reservoir. If after a period of time the level detector indicates the reservoir level is still low, the valve will cause liquid to be drawn from a different container. The aspirator is deactivated a period of time after the level detector indicates that the reservoir level is normal.

대표청구항 ▼

An improved system for dispensing liquid chemicals, such as photoresist, from a pair of containers comprising: a. first conduit means mounted in liquid-flow communication with a first container of the pair for carrying liquid therefrom; b. second conduit means mounted in liquid-flow communication wi

An improved system for dispensing liquid chemicals, such as photoresist, from a pair of containers comprising: a. first conduit means mounted in liquid-flow communication with a first container of the pair for carrying liquid therefrom; b. second conduit means mounted in liquid-flow communication with a second container of the pair for carrying liquid therefrom; c. controllable valve means connected in liquid-flow communication with the first and second conduit means to selectively, in a first position, block the flow of liquid through the second conduit means while permitting flow through the first conduit means and, in a second position, block the flow of liquid through the first conduit means while permitting flow through the second conduit means; d. reservoir means connected in liquid-flow communication with the controllable valve means to receive liquid from the first and second conduit means via the controllable valve means, the reservoir means including a container for holding a volume of received liquid; e. pump means connected in liquid-flow communication with said container for withdrawing liquid therefrom; f. level sensing means mounted to monitor the level of liquid within said container and to provide an output signal indicative of whether the liquid level has fallen below a predetermined location; g. switching means connected to receive the output signals from the level sensing means and mounted to actuate the controllable valve means in response to such signals to switch from flow communications with one of the containers of the pair to the other; and h. air withdrawal means connected to the reservoir means to withdraw air from the reservoir means above the level of liquid therein.