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Inspection of Adhesion in Magneto-Optic Thin Film Structures

IP.com Disclosure Number: IPCOM000035179D
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Meeks, SW: AUTHOR [+2]

Abstract

A new method is described of fast, non-contact inspection of the quality of adhesion of thin films in the magneto-optic (M/O) disk structure and in other layered structures. Complete or partial inspection of magneto-optic disks is needed in manufacturing to detect delaminations between films and the substrates and between bonded disks. A new technique will be described which can be used to determine the quality of adhesion of thin films in the magneto-optic structure. This invention also can be used to determine the quality of adhesion of two disks which are bonded by an epoxy layer. The limitation of the majority of acoustic techniques is that they require contact with liquids and are generally slow. Of course, liquids cannot be allowed in contact with the active side of the disk.

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Inspection of Adhesion in Magneto-Optic Thin Film Structures

A new method is described of fast, non-contact inspection of the quality of adhesion of thin films in the magneto-optic (M/O) disk structure and in other layered structures. Complete or partial inspection of magneto-optic disks is needed in manufacturing to detect delaminations between films and the substrates and between bonded disks. A new technique will be described which can be used to determine the quality of adhesion of thin films in the magneto- optic structure. This invention also can be used to determine the quality of adhesion of two disks which are bonded by an epoxy layer. The limitation of the majority of acoustic techniques is that they require contact with liquids and are generally slow. Of course, liquids cannot be allowed in contact with the active side of the disk. This invention proposes an inspection technique which is based on piezoelectric generation of acoustic waves and optical detection of the same acoustic waves. This inspection technique has a video detection rate and uses liquid coupling only from the substrate side of the disk.

The principle of the technique to detect delaminations in the magneto-optic thin film structure is shown in the figure. It is based upon an acousto-optic technique. This technique does not require that a coupling fluid be in contact with the M/O thin film. The technique uses an "O"-ring to seal the coupling fluid from the thin film. The seal is made at the edges of the glass substrate as shown in the figure. An acoustic transducer, which is located beneath the glass substrate, transmits an acoustic wave at 10...