Patent ID: 7052826

Claim:
A monitoring method for photoresist regeneration, comprising the steps of: (a) diluting the waste photoresist with photoresist thinner into different viscosities (μ 0 ); (b) measuring the solid content (C 0 ) of said photoresists having different viscosities (μ 0 ) and their coated thickness(H f ) under fixed spin speed; (c) using steps (a) and (b) to establish the relationship of viscosity, solid content and film thickness of waste photoresist, and thereby, to obtain the values of constants k 0 , α, and μ in Equation (I) H f =k 0 C 0 α μ 0 β ; (d) substituting the target thickness desired in actual operation into Equation (I) H f =k 0 C 0 α β 0 β with known constants k 0 , α, and β obtained in step (c) to calculate the target solid content and viscosity of the regenerated photoresist; and (e) monitoring the solid content and viscosity of the photoresist to be regenerated to observe their proximity to the target values obtained in step (d) so as to determine whether said photoresist could be recycled as regenerated photoresist.