Processing liquid supply method, processing liquid supply apparatus and storage medium

A method for wetting a filter, the method comprising:

• providing an apparatus for wetting the filter comprising:
• a processing liquid supply container;
• a filter unit including the filter therein, an introducing port, an external supply port and a venting port, the introducing port of the filter unit being connected to the processing liquid supply container through a first pipe including an upstream side valve thereon and provided at an upstream side of the filter unit;
• a decompressing unit configured to decompress inside of the filter unit,
• the decompressing unit comprising:
• a first trap tank connected to the venting port of the filter unit through a third pipe including a venting valve thereon, an end of a first drainage pipe including a first decompressing valve thereon being connected to a bottom portion of the first trap tank;
• a second trap tank connected to a second pipe through a fourth pipe including a first downstream side valve thereon, an end of a second drainage pipe including a second decompressing valve thereon being connected to a bottom portion of the second trap tank;
• a vacuum trap tank connected to each top portion of the first trap tank and the second trap tank through a first exhaust pipe including a first exhaust valve thereon and a second exhaust pipe including a second exhaust valve thereon, respectively;
• and
• an exhaust passage connected to a top portion of the vacuum trap tank through a third exhaust pipe including a third exhaust valve on said third exhaust pipe, and
• a third trap tank connected to the external supply port of the filter unit through the second pipe including a second downstream side valve thereon at a downstream side of the filter unit that is positioned at an opposite side of the upstream side of the filter unit, and configured to collect bubbles in the processing liquid and remove the collected bubbles through a third drainage pipe, an end of the third drainage pipe being connected to a top portion of the third trap tank;
• and
• a pump connected to a bottom portion of the third trap tank, and
• filling a processing liquid into the filter unit by supplying the processing liquid therein from the processing liquid supply container such that the filter of the filter unit is immersed in the processing liquid;
• after the filling the processing liquid, decompressing, by the decompressing unit, the inside of the filter unit into a first pressure atmosphere that is a negative pressure atmosphere while closing the upstream side valve, the first decompressing valve, the second decompressing valve, and the second downstream side valve and while opening the venting valve, the first exhaust valve, the first downstream side valve, the second exhaust valve and the third exhaust valve such that the processing liquid filled in the filter unit is sucked through the venting port and the external supply port of the filter unit to further immerse the filter of the filter unit in the processing liquid, thereby drawing the bubbles remaining in portions where the filter of the filter unit is not immersed in the processing liquid in the filling the processing liquid from the filter of the filter unit toward the venting port and the external supply port of the filter unit and removing the bubbles from the filter of the filter unit;
• after the decompressing the inside of the filter unit, opening the first decompressing valve and the second decompressing valve of the decompressing unit while closing the upstream side valve and the second downstream side valve and while opening the venting valve, the first downstream side valve, the first exhaust valve, the second exhaust valve and the third exhaust valve such that the inside of the filter unit is boosted from the first pressure atmosphere to an atmospheric pressure outside the filter unit, thereby increasing a pressure acting on the bubbles drawn to the venting port and the external supply port of the filter unit and dissolving the bubbles in the processing liquid filled in the filter unit;
• and
• after the opening the first decompressing valve and the second decompressing valve of the decompressing unit, suctioning, by the pump, to decompress the downstream side of the filter unit to a pressure greater than the first pressure atmosphere which is also less than the atmospheric pressure while opening the upstream side valve, the second downstream side valve and a third downstream side valve, said third downstream side valve located between the third tank trap and the pump;
• and while closing the venting valve, the first decompressing valve, the first downstream side valve and the second decompressing valve such that the processing liquid flows from the processing liquid supply container to the downstream side of the filter unit.