Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making named article
Reexamination Certificate
2001-06-28
2003-09-30
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making named article
C430S313000, C430S314000, C430S320000
Reexamination Certificate
active
06627390
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to magnetic transducer elements employed within magnetic data storage and retrieval. More particularly, the present invention relates to plating methods for forming plated layers within magnetic transducer elements employed within magnetic data storage and retrieval.
2. Description of the Related Art
The recent and continuing advances in computer and information technology have been made possible not only by the correlating advances in the functionality, reliability and speed of semiconductor integrated circuits, but also by the correlating advances in the storage density and reliability of direct access storage devices (DASDs) employed in digitally encoded magnetic data storage and retrieval.
Storage density of direct access storage devices (DASDs) is typically determined as areal storage density of a magnetic data storage medium formed upon a rotating magnetic data storage disk within a direct access storage device (DASD) magnetic data storage enclosure. The areal storage density of the magnetic data storage medium is defined largely by the track width, the track spacing and the linear magnetic domain density within the magnetic data storage medium. The track width, the track spacing and the linear magnetic domain density within the magnetic data storage medium are in turn determined by several principal factors, including but not limited to: (1) the magnetic read-write characteristics of a magnetic read-write head employed in reading and writing digitally encoded magnetic data from and into the magnetic data storage medium; (2) the magnetic domain characteristics of the magnetic data storage medium; and (3) the separation distance of the magnetic read-write head from the magnetic data storage medium.
While magnetic read-write heads are thus integral and essential within the art of magnetic data storage and retrieval, magnetic read-write heads are nonetheless not fabricated entirely without problems within the art of magnetic data storage and retrieval. In that regard, it is known in the art of magnetic data storage and retrieval that magnetic transducer elements within magnetic read-write heads, which magnetic transducer elements are typically required to be formed with uniform and controlled dimensions as areal recoding densities of magnetic data storage media increase, are often difficult to fabricate with such requisite levels of uniformity and dimensional control.
It is thus towards the goal of providing within magnetic read-write head fabrication methods through which may be formed within magnetic read-write heads magnetic transducer elements with enhanced uniformity and dimensional control that the present invention is directed.
Various magnetic transducer elements having desirable properties, and/or methods for fabrication thereof, have been disclosed within the art of magnetic read-write head fabrication.
For example, Chen et al., in U.S. Pat. No. 5,282,308, disclose a method for forming within a magnetic transducer element, with reduced process complexity and relaxed registration alignment tolerance requirements, a stitched upper magnetic pole layer comprising: (1) an upper magnetic pole tip layer having formed partially contacting and overlapping thereupon, and aligned thereto; (2) an upper magnetic pole yoke layer. The method realizes the foregoing objects by employing when forming the stitched upper magnetic pole layer a radiation hardened portion of a photoresist masking frame employed for forming the upper magnetic pole tip layer, where the radiation hardened portion of the photoresist masking frame provides a stitching pedestal at a location adjoining an overlap of the upper magnetic pole tip layer and the upper magnetic pole yoke layer.
In addition, Ju et al., in U.S. Pat. No. 5,285,340, discloses a magnetic transducer element wherein a lower magnetic pole tip layer and an upper magnetic pole tip layer which are sandwiched between and contacting, respectively, a corresponding lower magnetic pole yoke layer and a corresponding upper magnetic pole yoke layer within the magnetic transducer element are precisely aligned with an equivalent pole tip width, and where each of the lower magnetic pole tip layer and the upper magnetic pole tip layer has a thickness closely controlled. The magnetic transducer element employs when forming the upper pole tip layer separated from the lower pole tip layer by a gap filling layer within the magnetic transducer element a single photoresist masking frame in conjunction with a sequential photoresist masking frame plating method to provide a photoresist masking frame plated composite lower magnetic pole tip layer/gap filling layer/upper magnetic pole tip layer fully areally aligned.
Further, Chen et al., in U.S. Pat. No. 5,652,687, discloses a magnetic transducer element which is formed with a narrow and well defined magnetic pole tip layer width, and thus also a narrow and well defined trackwidth of the magnetic transducer element, and wherein there is also avoided magnetic saturation of the magnetic transducer element. To realize the foregoing objects, there is employed when forming the magnetic transducer element a “U” shaped notch formed into a non-magnetic layer formed interposed between a lower magnetic pole yoke layer and an upper magnetic pole yoke layer within the magnetic transducer element, and wherein there is formed into the “U” shaped notch at least one magnetic pole tip layer within the magnetic transducer element.
Still further, Ju et al., in U.S. Pat. No. 5,843,521, discloses a photoresist masking frame plating method for forming a photoresist masking frame plated magnetic pole layer within a magnetic transducer element, where: (1) the photoresist masking frame plated magnetic pole layer is a photoresist masking frame plated notched magnetic pole layer having a notch formed therein at a juncture with a seed layer employed within the photoresist masking frame plating method since a photoresist masking frame employed within the photoresist masking frame plating method has a foot formed therein at the juncture with the seed layer; and (2) there is avoided when electromagnetically energizing a magnetic write head having formed therein the magnetic transducer element a magnetic write field gradient boundary decompression incident to forming the photoresist masking frame plated notched magnetic pole layer through the photoresist frame plating method. The method realizes the foregoing object by employing when forming the photoresist frame plated notched magnetic pole layer the seed layer formed of a thickness and of a material which compensates when electromagnetically energizing the magnetic write head for the magnetic write field gradient boundary decompression between the photoresist masking frame plated notched magnetic pole layer and a second magnetic pole layer.
Finally, Feng et al., in U.S. Pat. No. 5,878,481, discloses a magnetic pole layer trimming method for forming within a magnetic transducer element a lower magnetic pole tip within a lower magnetic pole layer separated from an upper magnetic pole tip within an upper magnetic pole layer by a gap filling dielectric layer, with minimal consumption of the upper magnetic pole tip, wherein: (1) the lower magnetic pole layer and the upper magnetic pole layer are formed of a permalloy magnetic material; and (2) the gap filling dielectric layer is formed of an aluminum oxide dielectric material. The method realizes the foregoing object by employing when forming the lower magnetic pole tip within the lower magnetic pole layer while employing the upper magnetic pole tip within the upper magnetic pole layer as a mask a reactive ion beam etch (RIBE) method employing a carbon tetrafluoride etchant gas.
Desirable within the art of magnetic head fabrication and magnetic transducer element fabrication are additional methods and materials through which there may be formed within magnetic transducer elements layers with enhanced uniformity and dimensional control.
It is towards the
Chang Jei-Wei
Hu Yining
Ju Kochan
Liu Yi-Chun
Wu Xue Hua
Ackerman Stephen B.
Baxter Janet
Gilliam Barbara
Headway Technologies Inc.
Saile George O.
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