Patent ID: 8080114

Claim:
A cleaning process comprising: loading a wafer in a high pressure cleaner having an upper element and a lower element, each of the upper element and lower element having a pneumatic cylinder insertion unit in which a pneumatic cylinder sliding from a side can be inserted; injecting high-purity gaseous carbon dioxide (CO 2 ) having first low pressure of less than 20 psig into the high pressure cleaner without sealing the high pressure cleaner by separating the upper element and the lower element; after sealing the high pressure cleaner by combining the upper element and the lower element and by inserting the pneumatic cylinder into the pneumatic cylinder insertion unit of the upper element and the pneumatic cylinder insertion unit of the lower element, injecting high purity CO 2 having second pressure of 30-50 bar into the high pressure cleaner; injecting high purity CO 2 to adjust the pressure in the high pressure cleaner to a third pressure that is 10-40 bar lower than a supercritical cleaning pressure of 120-300 bar; providing a homogeneous transparent phase mixer; introducing a cleaning additive having a pressure less than 10 bar to the homogeneous transparent phase mixer; adding supercritical CO 2 having a pressure greater than the supercritical cleaning pressure to the cleaning additive in the homogeneous transparent mixer; using the mixing effect caused by the pressure difference between the cleaning additive and the supercritical CO 2 to instantaneously mix a homogeneous transparent phase mixture comprising the cleaning additive and supercritical CO 2 ; cleaning the wafer by injecting the supercritical homogeneous transparent phase mixture into the high pressure cleaner, which is at the third pressure, under the supercritical cleaning pressure; rinsing the wafer by injecting a supercritical rinsing mixture at a rinsing pressure of about 80-250 bar in which a rinsing additive and supercritical CO 2 are mixed, into the high pressure cleaner; and separating CO 2 from a mixture discharged from the high pressure cleaner.