Title:
DETECTING APPARATUS FOR CHANGE IN FILM THICKNESS
Document Type and Number:
Japanese Patent JPH0534114
Kind Code:
A
Abstract:
PURPOSE:To measure the change in thickness of a film highly accurately by measuring the thickness of the film with optical interference, and analyzing the frequency. CONSTITUTION:The light from a laser 5 is cast on a thin film sample 1. The interference of the reflections of the lights from the upper surface and the rear surface of the sample is detected with a photodiode 7. The frequency is analyzed with a computer 9 through an analog-digital converter 8. In this way, the change in thickness with regard to a multilayered thin film which cannot be measured by a conventional method and a sample which swells in dissolution can be readily measured. The change in thickness of the film can be accurately obtained at a high speed because it is not necessary to prepare the complicated theory of the interference of multilayered thin film and the model of a swelling layer.
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Inventors:
CHOKAI MINORU
Application Number:
JP18858591A
Publication Date:
February 09, 1993
Filing Date:
July 29, 1991
Export Citation:
Assignee:
HITACHI LTD
International Classes:
G01B11/06; (IPC1-7): G01B11/06
Attorney, Agent or Firm:
Ogawa Katsuo