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Technique for Sensing Induced Stresses in Composite Magnetic Thin Film Structures

IP.com Disclosure Number: IPCOM000040864D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hamaker, RW: AUTHOR [+3]

Abstract

A method is described for determining the magnitude of thermal or mechanically induced stresses in composite magnetic thin film. The method utilizes measurements of hard axis saturation field (Hk) both before and after deposition of potentially stress causing materials.

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Technique for Sensing Induced Stresses in Composite Magnetic Thin Film Structures

A method is described for determining the magnitude of thermal or mechanically induced stresses in composite magnetic thin film. The method utilizes measurements of hard axis saturation field (Hk) both before and after deposition of potentially stress causing materials.

The method utilizes a monitor coupon which is processed along with the product wafers through deposition of the plated magnetic film. The plated magnetic film on the monitor coupon then has a bar pattern defined and etched by standard photolitho- graphy techniques. The bar pattern is oriented with the axis parallel to the easy axis of film magnetization. This pattern introduces a shape anisotropy in the magnetically oriented film to insure against the film becoming isotropic after later alumina overcoat deposition. A measurement of Hk is made on the monitor film after the bar pattern definition. Care should be taken to remove all resist material from the monitor coupon prior to subjecting the monitor coupon to continuing process along with the product wafers.

After the alumina overcoat deposition, the monitor coupon is removed and Hk is again measured. Any increase will be directly proportional to the residual thermal stress intensity induced in the film during the elevated temperature of the overcoat depositio cycle. The monitor coupon is then returned to the product wafer lot for continued processing.

After the ove...