METHOD FOR MEASURING SURFACE AREA CHANGE RATIO OF POLYSILICON THIN FILM HAVING HEMISPHERICAL GRAIN, AND METHOD AND DEVICE FOR MEASURING CAPACITANCE USING THE SAME

PROBLEM TO BE SOLVED: To accurately acquire a surface area change ratio, by a method wherein a polysilicon thin film having a hemispherical grain is formed, and an area change ratio is calculated by measuring a height and a porosity of the hemispherical grain. SOLUTION: A polysilicon thin film having a hemispherical grain is formed, and a height (t) and a porosity (fν) of the hemispherical grain of the polysilicon thin film are measured, and these are substituted for formula I to calculate an area change ratio CE. And, a thickness (d) of a dielectric film as a capacitor, a dielectric constant ( ) and an area change ratio CE are substituted for formula II, to calculate a capacitance change ratio Cr. Thus, prior to completion of the capacitor, a change of capacitance can accurately be known. Incidentally, the area change ratio is monitored near to an actual value at a stage of forming the hemispherical grain on a surface of the polysilicon thin film, whereby it is possible to enhance reliability and a manufacturing yield of the capacitor.