Patent ID: 7784998

Claim:
A method for liquid mixing supply comprising: forming a diluted specific liquid chemical; supplying the diluted specific liquid chemical to a mixing tank; and supplying at least two liquid chemicals and ultra pure water to the mixing tank at a predetermined ratio, and mixing them, wherein starting points of supplying the at least two liquid chemicals and the ultra pure water are different from each other, forming the diluted specific liquid chemical includes supplying a specific liquid chemical to a first tank, supplying first ultra pure water to a second tank such that the first ultra pure water supplied to the second tank has not mixed with the specific liquid chemical, transferring the specific liquid chemical to the second tank to mix the specific liquid chemical with the first ultra pure water to form the diluted specific liquid chemical, and in the supplying of the at least two liquid chemicals and the ultra pure water, the at least two liquid chemicals and the ultra pure water are sequentially supplied in a descending order of a supply amount or a supply ratio.