VoDM-C Vapor on Demand Module – MKS

A need has been demonstrated for the reliable delivery of water vapor into photoresist strip and post metal etch passivation processes. This has previously been done using a heated vessel of water that produces the vapor and a flow controller to deliver the vapor to the process. Attempts have been made to control this vapor flow with needle valves, thermal mass flow controllers and choked flow technology. These schemes work until the heated reservoir must be refilled. The addition of liquid water to the reservoir causes a drop in its temperature, a concurrent drop in its vapor pressure, and loss of driving force for the vapor into the process.

MKS Instruments has developed a single unit, the Vapor on Demand Module, that uses a continuous flow of liquid, eliminating the problems associated with refilling the source vessel. The Vapor on Demand Module, or VoDM, consists of a vaporizer section and a vapor controller section. Liquid is fed directly from the house DI water supply into the vaporizer. The vapor produced is then fed to the mass flow controller which is based on the MKS 1153 Vapor Phase Mass Flow Controller. The control circuits for the various control elembents, liquid, vapor and power, are internally controlled by an onboard microprocessor to provide smooth and responsibe delivery of water vapor to the process. Communications with the tool are through an analog I/O where flow rate set point and valve overrides are input, and the flow rate of delivered vapor and downstream pressure are reported.

Obsolete product, contact CCR for alternatives.