Patent ID: 7867559

Claim:
A method for supplying a photoresist coating liquid comprising: providing a photoresist coating liquid supplying apparatus comprising a buffer vessel for a photoresist coating liquid, a circulation filtering apparatus for filtering a part of the photoresist coating liquid within the buffer vessel through a filter and then returning the filtered photoresist coating liquid to the mother liquid of the photoresist coating liquid, and a pipe for supplying the photoresist coating liquid from the buffer vessel or the circulation filtering apparatus to a photoresist coating apparatus; and, while steadily circulation-filtering the photoresist coating liquid stored in the buffer vessel, supplying the photoresist coating liquid to the coating apparatus, further wherein the pipe for supplying the photoresist coating liquid from the buffer vessel into the photoresist coating apparatus is connected to a second buffer vessel provided on the upstream of the coating apparatus, which further comprises a valve provided on the upstream of the second buffer vessel, a liquid level sensor provided in the second buffer vessel, and a control system for controlling the valve by a signal sent from the liquid level sensor to regulate the volume of the photoresist coating liquid within the second buffer vessel.