Patent ID: 7272206

Claim:
A method for measuring a void content of a sample which is made of a thin film having a matrix and voids dispersed in the matrix comprising the steps of: (a) preparing a first sample having a known void content and a second sample having an unknown void content; (b) executing an X-ray reflectance measurement for the first sample to get a first reflectance profile and determining an average density and a film thickness of the first sample based on the first reflectance profile; (c) executing an X-ray small angle scattering measurement for the first sample to get a first measured profile of a scattered X-ray intensity, and carrying out a parameter fitting operation between the first measured profile of the scattered X-ray intensity and a theoretical profile of the scattered X-ray intensity, which is calculated based on the average density and the film thickness of the first sample, to determine a first scale factor of the scattered X-ray intensity; (d) calculating an equipment constant of an X-ray small angle scattering measurement equipment based on the first scale factor and the known void content of the first sample; (e) executing an X-ray reflectance measurement for the second sample to get a second reflectance profile and determining an average density and a film thickness of the second sample based on the second reflectance profile; (f) executing an X-ray small angle scattering measurement for the second sample using the same X-ray small angle scattering measurement equipment as for the first sample to get a second measured profile of the scattered X-ray intensity, and carrying out a parameter fitting operation between the second measured profile of the scattered X-ray intensity and a theoretical profile of the scattered X-ray intensity, which is calculated based on the average density and the film thickness of the second sample, to determine a second scale factor of the scattered X-ray intensity; (g) calculating a void content of the second sample based on the equipment constant and the second scale factor; and (h) generating a signal indicative of the calculated void content.