International Business Machines Corporation

James Hsi-Tang Lee

Mohamad Towfik Krounbi

Robert Fontana

James K Howard

Hiroyuki Hiraoka

Akella V Satya

Haralambos Lefakis

Po-Kang Wang

Cherngye Hwang

Mao-Min Chen

Jerome Michael Eldridge

Ching Hwa Tsang

Scott Arthur MacDonald

Carlton G Willson

Jeffrey W Labadie

Kenneth Ting-Yuan Kung

Ashwin K Ghatalia

Donald R Thomas

Heidi L Dickstein

Lucas S Chang

Jyh-Shiliey Jerry Lo

Bernd K Lessmann

Tiee-Ghow Wang

An improved method of manufacturing is provided for making an improved merged MR head. The method employs a photoresist mask with appropriately-sized openings for simultaneously etching numerous vias to various depths over a set time period. After formation of the vias, a single photoresist mask is employed to pattern in one step gap layers G3, G2, G1 and a first shield layer S1 to the desired lateral configuration for the merged MR head. Subsequent to patterning these thin film layers, double insulation layers I2 and I3 are individually soft baked on top of the coil structure of the head followed by patterning of the layers I2/I3 by a single photoresist mask. These layers are then hard baked to retain the desired smooth configuration of the layers. The improved merged MR head has a smooth configuration to its top pole piece P2 because of the smooth configuration of the I2/I3 layer so that flux leakage and saturation problems are minimized.

Simplified magnetic head with common write gap/first insulation layer

Simplified method of making merged MR head

Simplified method of making vias for merged MR head

A magnetoresistive (MR) read transducer having passive end regions separated by a central active region in which an MR layer is formed over substantially only the central active region and in which a magnetic bias layers is formed in each passive end region. Each of the magnetic bias layers includes a layer of ferromagnetic material and a layer of antiferromagnetic material overlaying and in contact with the ferromagnetic layer to provide an exchange-coupled magnetic bias field. Each of the magnetic bias layers form an abutting junction having magnetic and electrically continuity with the MR layer to produce a longitudinal magnetic bias field in the transducer.

Method of manufacturing magnetoresistive read transducer having a

Improved processes for generating a structure having beveled edges are presented. In a preferred embodiment, two photoresist layers are successively deposited on top of the target material, e.g., a metallization film. The intermediate photoresist layer is developed beyond the lithographically delineated boundaries of the top photoresist layer, forming deep recesses. These recesses remain unchanged during the subsequent etching step, resulting in pre-defined edge profiles in the target material.

Process for generating beveled edges

A magnetoresistive (MR) read transducer comprising a thin film MR layer formed of ferromagnetic material and a nonmagnetic thin film spacer layer in contact with the MR layer. The spacer layer comprises a material selected from the group consisting of nichrome and nichrome with chromium oxide. A thin film of soft magnetic material is deposited in contact with the spacer layer so that a transverse bias is produced in at least a part of the MR layer. A feature of the invention is that the resistivity of the spacer layer can be chosen by selecting the ratio of nichrome to chromium oxide in the spacer layer. In a specific embodiment the spacer layer extends over only the central region of the MR layer. In case the MR layer is a nickel based alloy, a wet chemical etching process using an etchant comprising an aqueous solution of ceric ammonium nitrate and acetic acid can be used to pattern the spacer layer.

Method for making a magnetoresistive read transducer

A magnetoresistive (MR) read transducer comprising a thin film MR layer formed of ferromagnetic material and a nonmagnetic thin film spacer layer in contact with the MR layer. The spacer layer comprises a material selected from the group consisting of nichrome and nichrome with chromium oxide. A thin film of soft magnetic material is deposited in contact with the spacer layer so that a transverse bias is produced in at least a part of the MR layer. A feature of the invention is that the resistivity of the spacer layer can be chosen by selected the ration of nichrome to chromium oxide in the spacer layer. In a specific embodiment the spacer layer extends over only the central region of the MR layer. In case the MR layer is a nickel based alloy, a wet chemical etching process using an etchant comprising an aqueous solution of ceric ammonium nitrate and acetic acid can be used pattern the spacer layer.

Magnetoresistive read transducer

A thin film magnetic head is provided in which the electrical insulation surrounding the conductive coil comprises a photosensitive resin which has been crosslinked by a thermally activated crosslinking agent or promotor. The addition of the thermally activated crosslinking agent or promotor greatly reduces both the cure temperature and cure time and results in enhanced dimensional stability without any deleterious effects.

Thin film magnetic heads with thermally crosslinked insulation

The reactive ion etching and thermal flow resistance of a resist image is enhanced by contacting the resist image with an alkyl metal compound of magnesium or aluminum.

Process for enhancing the resistance of a resist image to reactive ion

A complex test structure for integrated, semiconductor circuits in which the impurity regions of the test device are elongated, preferably in serpentine fashion. The elongated impurity regions emulate corresponding regions in regular integrated circuit devices. Additional regions are provided, each in elongated form, which, when impressed with appropriate voltages or currents, provide indications of defect levels and product yield in the regular devices. Advantageously, the serpentine test structure is fabricated on the same wafer and with the same process steps as the regular integrated circuit chips. In one embodiment, a plurality of such monitors are provided adjacent each other in the same test site. Regions in one monitor are selectively connected to regions in another monitor and to external contact pads by contact stations disposed between each monitor.

Integrated circuit test structure

A semiconductor defect monitoring structure employs a series of electrically testable serpentine stripe patterns having different widths and spacing in order to determine the distribution of the density of defects by size. Metal stripe patterns are superposed and rotated 90.degree. with respect to diffusion stripe patterns in a semiconductor wafer. A set of four field effect transistor devices are connected to each stripe pattern in such a way that tests may be made for all defects without interference between adjacent patterns. The defect monitoring structure helps to determine defects such as opens in diffusion and metallization, shorts in metallization, shorts in diffusion, pinholes in a thin oxide, and pinholes in a thick oxide.

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San Jose, CA, United States of America

James Hsi-Tang Lee