Abstract: A liquid process tank that provides a quick dump feature includes a fixed bottom wall assembly and moveable tank side walls that contain liquid and also act as a quick dump valve for the liquid. The bottom wall assembly includes an acoustic transducer secured thereto. The tank side walls are secured to a plurality of linear actuators adapted for vertical movement. A seal is secured to the lower edge of the side wall assembly to impinge on a land surface that extends about the perimeter of the bottom wall assembly. The linear actuators are retracted to draw join the bottom and side wall assemblies to retain liquid, or activated in unison to drive the tank walls upwardly from the fixed bottom wall assembly, creating a bottom opening in the tank that quickly discharges all the liquid from the tank.

Abstract: In a substrate bath that processes substrate wafers using megasonic energy, a tank that is provided with reflecting surfaces that direct the megasonic energy to those portions of the substrates that would otherwise be sonically shadowed by the cassette that supports the substrates. In one aspect, a pair of curved wall surfaces are formed within the tank, each extending from one side wall to the bottom wall in curvilinear fashion and oriented longitudinally, the paired curved wall surfaces being disposed in laterally spaced, enantiomorpic relationship. The curved surfaces are arranged so that a significant amount of the megasonic energy impinges at an angle less than the critical angle, so that the energy is reflected in a diverging field that intersects the substrates and strikes those portions of the substrates that are shadowed by the cassette structure. Thus the megasonic cleaning, (etching or processing of the substrate) process is improved significantly.

Abstract: A cassette for supporting electrical component substrates in a megasonic processing bath includes a pair of end panels spaced apart longitudinally, a pair of side rails extending longitudinally along opposed sides of the substrate cassette, and at least one bottom support extending between lower portions of the end panels. The supports include a plurality of shallow channels extending laterally therein and spaced regularly therealong to receive edge portions of the substrates. The side rails and bottom supports of the cassette are all formed of plate components that are dimensioned to transmit the maximum amount of the megasonic energy projected into the processing bath, so that the components do not cause sound-shadowing of the substrates supported in the cassette. The side rails and bottom supports are formed of narrow plates having a thickness equal to an integer multiple (i.e., 1, 2, 3, etc.) or an even fractional (i.e., ½, ¼, etc.