Method of measuring thickness of film formed on surface of ferromagnetic substance

Abstract

Abstract PURPOSE:To accurately measure the thickness of a nonmagnetic film formed on the surface of a ferromagnetic substance, by a probe wherein both magntic poles of a magnet are disposed to face the same plane at two different points and a magnetic sensor is attached to either one of the magnetic poles. CONSTITUTION:Two magnetic poles of a magnet are disposed to face the same plane at two different points and a magnetic sensor is bonded to either one of the magnetic poles of such magnet to form the film thickness detecting end, so that a film thickness detecting probe is constituted. Output from the magnetic sensor which generates when the probe is abutted with the measured material is detected to measure the density of magnetic flux, thereby to gauge a thickness of a nonmagnetic film formed on the surface of a ferromagnetic substance. For example, intermediates 5, 5' extending from both poles of a magnet 3 are abutted via a spacer 6 with the surface of a ferromagnetic substance 1 having a nonmagnetic film 2 thereon. A magnetic sensor 4 formed of indium antimony or others is attached to the intermediate 5 having a smaller area. Output from the magnetic sensor 4 is compared with output from a compensating sensor 4' to obtain a film thickness of the nonmagnetic substance 2.

Inventors

• 👤 Keigo Sasabayashi
• 👤 Atsuhiko Matsuda
• 👤 Nobuyuki Yamaji
• 👤 Junichi Ujigawa

Bibliographic Details