A workpiece processing station is disclosed. The workpiece processing
station has particular applicability in an electroplating process for
semiconductor wafers. The apparatus includes a work processing bowl
having an outer bowl and an inner cup positioned at a location slightly
below the upper rim of the bowl. An annular space is provided between the
sides of the processing bowl and the fluid cup. Fluid is provided to the
fluid cup through an opening in the bottom of the fluid cup. The fluid
overflows the fluid cup and drains down the open annular space between
the process bowl and the fluid cup and passes through the opening in the
bottom of the process bowl and into a fluid reservoir. A reservoir is
preferably used as both the supply and the return for the process fluid.
The apparatus further includes filters disposed within the bottom of each
fluid cup between the bottom of the fluid cup and the process fluid inlet
line such that the process fluid must flow upward through the filter
before entering the upper portion of the fluid cup. In the preferred
embodiment, the workpiece processing station includes a plurality of the
process bowl assemblies all having a common reservoir in which process
fluid may drain. The invention also includes the method of flowing
process fluid into a process vessel such that it overflows and returns to
a common fluid return reservoir during the semiconductor manufacturing
process.