Patent ID: 8482741

Claim:
A method of calibrating an interferometric profilometer used for measuring a pole-tip recession in a magnetic-head slider having an air-bearing surface made of a composite material, the method comprising the following steps: using said profilometer to measure interference signals produced at a plurality of pixels by a first test material and by a second test material; assuming that M ij exp =α|r th |−β represents an empirical relationship between a known value of reflectivity r th for a material and an experimental modulation M ij exp produced by the material when measured with said profilometer, where α and β are system-dependent parameters related to the profilometer; and calculating α and β using said empirical relationship expressed as M 1 exp =α|r 1 th |−β, M 2 exp =αr 2 th |−β, where r 1 th and r 2 th are theoretical values of reflectivity of said first test material and second test material, respectively, and M 1 exp and M 2 exp are experimental modulations produced by said first test material and second test material, respectively, when measured with the profilometer; said calculating step being carried out with a computer; thereby calibrating the profilometer for measuring the pole-tip recession in the magnetic-head slider.