the present invention includes capacitive film thickness measurement devices and measurement systems . the invention also includes machines or instruments using those aspects of the invention . the present invention additionally includes methods and procedures using those devices of the present invention . the present invention discloses a capacitance measurement device and technique useful in determining lubricant film thickness on substrates such as magnetic thin - film rigid disks . using the present invention , variations in lubricant thickness on the angstrom scale or less may be measured quickly and nondestructively .