Substrate processing system

A substrate processing system, comprising:

• a processing chamber to process a substrate;
• a vaporizing unit to vaporize a material of liquid;
• a supply system to supply the processing chamber with gas of the material vaporized by the vaporizing unit;
• an exhaust system to exhaust an atmosphere in the processing chamber;
• and
• a cleaning liquid supply system to supply the vaporizing unit with cleaning liquid for cleaning a product deposited in the vaporizing unit, wherein
• the cleaning liquid supply system supplies at least two kinds of cleaning liquids into the vaporizing unit so that the product can be removed from the vaporizing unit by action of the two kinds of cleaning liquids on the product, the cleaning liquids include a first cleaning liquid and a second cleaning liquid, the first cleaning liquid is an aprotic solvent, the second cleaning liquid is a protic solvent,
• the cleaning liquid supply system including a source of the first cleaning liquid of an aprotic solvent and a separate source of the second cleaning liquid of a protic solvent, and a controller for controlling flow of the first and second cleaning liquids, wherein said sources of the first cleaning liquid and of the second cleaning liquid connect to said vaporizing unit, and
• the controller controls the cleaning liquid supply system to perform a multiple-step cleaning process of a sequential application of the protic solvent after the application of the aprotic solvent, to thereby:
• supply the protic solvent second cleaning liquid to the vaporizing unit
• after the aprotic solvent first cleaning liquid is supplied to the vaporizing unit and
• after the aprotic solvent first cleaning liquid permeates into the product for a constant time,
• and, after the aprotic solvent first cleaning liquid permeates into the product for said constant time, the supplied protic solvent second cleaning liquid reacts with the product while the aprotic solvent first cleaning liquid is in the vaporizing unit.