Method for measuring layer thickness and viscoelastic coefficient, and apparatus for measuring layer thickness and viscoelastic coefficient

摘要

PROBLEM TO BE SOLVED: To measure the thickness of a layer formed on a piezoelectric element with high accuracy from an initial stage. In a method for measuring a layer thickness and a viscoelastic coefficient, a sensor having a piezoelectric element having a resonance frequency is immersed in a solution. The amount of change ΔFs1 in which the fundamental frequency Fs1 of the resonance frequency shifts, the amount of variation ΔFsn in which the frequency Fsn of the higher-order wave of the resonance frequency shifts, and the fundamental frequency are the peaks, which are caused by forming a layer on the piezoelectric element in the solution. A change amount ΔFw1 in which the full width at half maximum Fw1 of the peak waveform is shifted and a change amount ΔFwn in which the full width at half maximum Fwn of the peak waveform whose peak is the high-order wave is shifted are acquired. Using the evaluation function from the change amount ΔFs1, the change amount ΔFsn, the change amount ΔFw1 and the change amount ΔFwn, a loss based on the layer thickness h, the storage elastic modulus G′ of the layer, and the fundamental frequency Fs1 of the layer. The elastic modulus G1″ and the loss elastic modulus Gn″ based on the frequency Fsn of the higher-order wave of the layer are calculated. [Selection diagram] Figure 1