System for controlling fluid flow

DETAILED DESCRIPTION Preferred embodiments of the invention are illustrated in the FIGURES, like numerals being used to refer to like and corresponding parts of the various drawings.
Embodiments of the present invention provide systems and methods of controlling fluid dispense to ensure clean break off of fluid at the end of a dispense process and to reduce crystallization of fluid in the dispense nozzle.
One embodiment of the present invention can include a controller that can generate a flow control signal according to a first close rate parameter to cause a control valve to close for a first segment of the close range and to generate the flow control signal according to a second close rate parameter to cause the control valve to close for a second segment of the close range.
The close rate parameter can result in closing the valve at a controlled rate, change in rate, or change in rate of change.
By adjusting the close rate parameters, severe oscillation at the end of the dispense process can be reduced or prevented.
Additionally, the controller can generate a suckback control signal to cause a suckback valve to push fluid to the end of a nozzle, draw fluid up into the nozzle or assist in cutting of the dispense more smoothly or more quickly.
Because fluid is pushed to the end of the nozzle, the fluid can absorb droplets remaining in the nozzle.
FIG.
1 is a diagrammatic representation of one embodiment of a fluid dispense system 10.
Fluid dispense system 10 can include a fluid control device 12, flow monitor 14 in fluid communication with control device 12, a suckback device 16 in fluid communication with flow monitor 14, and a nozzle 18 in fluid communication with suckback valve 16.
The outlet of suckback valve 16 can lead to nozzle 18 for dispensing a liquid to a wafer or other object.
A controller 20 can be coupled to flow rate monitor 14, fluid control device 12 and suckback device 16 by one or more signal lines.
According to one embodiment of the present invention, fluid control device 12 can include any proportional control valve