Abstract: Semiconductor wafers are vertically loaded into a cassette, the cassette is placed on a support structure, the cassette and support structure are placed in a drop-in tank, and the drop-in tank is placed inside a larger tank containing etching solution. Holes in the drop-in tank allow the etching solution in the larger tank to enter and fill the drop-in tank. A pump sucks etching solution out of the larger tank and as a result, also sucks etching solution out of the drop-in tank through the holes. The pumped out solution is then filtered of residue waste resulting from the etching process, and the filtered solution is pumped into a hollow portion of the support structure and from thence, out of the hollow portion through holes formed on a top surface of the support structure, generating thereby, currents of filtered etching solution.

Abstract: A plurality of semiconductor wafers are vertically loaded into a cassette, the cassette is placed on a support structure, the cassette and support structure are placed in a drop-in tank, and the drop-in tank is placed inside a larger tank containing etching solution. A plurality of holes in the drop-in tank allow the etching solution in the larger tank to enter and fill the drop-in tank. A pump sucks etching solution out of the larger tank and as a result, also sucks etching solution out of the drop-in tank through the plurality of holes. The pumped out solution is then filtered of residue waste resulting from the etching process, and the filtered solution is pumped into a hollow portion of the support structure and from thence, out of the hollow portion through a plurality of holes formed on a top surface of the support structure, generating thereby, currents of filtered etching solution.