Patent ID: 8460478

Claim:
A semiconductor apparatus, comprising: a first tank including a first fluid and a plurality of semiconductor substrates to be processed, therein; a second tank configured to receive overflow of the first fluid from the first tank into an upper portion of the second tank and configured to further accommodate a second fluid, the first and second tanks being exclusive of each other and the second tank being a mixing tank; a cycling system having at least one first conduit and configured to carry fluid to the first tank from the second tank via the at least one first conduit, the at least one first conduit having an end substantially below a surface of the second fluid near a bottom of the second tank; a fluid providing system with the second fluid therein and fluidly coupled to the second tank and configured to provide the second fluid into the second tank via at least one second conduit, the second fluid being a fresh fluid and the at least one second conduit having an end substantially below the surface of the second fluid within the second tank, near a bottom of the second tank; an overflow system coupled to the second tank and configured to remove an upper portion of fluid from the second tank when the surface of the second fluid is substantially equal to or higher than a pre-determined level remote from the ends of the first and second conduits; and a processor coupled to the fluid providing system and configured to deliver a signal to the fluid providing system and to control flow of the second fluid, the processor generating a signal corresponding to a number of the semiconductor substrates to control a flow rate of the second fluid flowing into the second tank, wherein the processor is configured to calculate an amount of the second fluid to be added into the second tank according to Y=50−3250/(65+0.28X), wherein Y represents the amount of the second fluid and X represents the number of the substrates, and the generated signal is based on the calculated amount.