Chemical-mechanical contouring (CMC) method for forming a contoured surface using a stair-step etch

• US 6,562,251 B1
• Filed: 07/26/2000
• Issued: 05/13/2003
• Est. Priority Date: 07/26/2000
• Status: Expired due to Fees

• Current Assignee: Aiwa (Sony Group Corp.)
• Original Assignee: Aiwa (Sony Group Corp.)
• Inventors: Jordan, Steven G.
• Primary Examiner(s): OLSEN, ALLAN W
• Application Number:
  US09/625,798
• Time in Patent Office: 1,021 Days
• Field of Search: 216/11, 216/22, 216/52, 216/57, 216/66, 216/75, 216/100, 296/030.7, 296/031.5, 296/031.6
• US Class Current: 216/22
• CPC Class Codes: G11B 15/62 Maintaining desired spacing between record carrier and head
• CPC Class Codes: G11B 5/1871 Shaping or contouring of the transducing or guiding surface
• CPC Class Codes: G11B 5/3106 where the integrated or assembled structure comprises means for conditioning against physical detrimental influence, e.g. wear, contamination G11B5/3133 takes precedence
• CPC Class Codes: G11B 5/3116 Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks G11B5/3113, G11B5/245 take precedence
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
• CPC Class Codes: G11B 5/3183 intersecting the gap plane, e.g. "horizontal head structure"
• CPC Class Codes: Y10T 29/49021 Magnetic recording reproducing transducer [e.g., tape head, core, etc.]
• CPC Class Codes: Y10T 29/49046 with etching or machining of magnetic material
• CPC Class Codes: Y10T 29/49048 Machining magnetic material [e.g., grinding, etching, polishing]

Abstract

A process of chemical-mechanical contouring (CMC) using a stair-step etch involves formation of an elevated layer of substrate overlying a device, in the illustrative example a thin-film magnetic head. The elevated layer of substrate is formed into a stair-step structure with the height and width of the stair-steps selected to attain a predetermined shape and size.

Claims

1. A thin film processing method comprising:

fabricating a finished thin film substrate including a plurality of magnetic thin-film head devices, the magnetic thin-film head devices having a head structure that is raised relative to a planar surface of the thin film substrate;

stair-step etching the head structure so that the individual thin-film head devices have the form of raised bumps with a plurality of stair-step edges; and

chemical mechanical contouring (CMC) the thin film substrate subsequent to the fabrication step to smooth the stair-step edges of the raised bumps to form substantially smooth, curved surfaces.

2. A method according to claim 1 further comprising:

stair-step etching the head structure by locating a central point of a device on the head structure surface, etching a sequence of stair-steps surrounding the central point, and controlling the width and depth of the stair-step etches as a function of distance from the central point.

3. A method according to claim 1 further comprising:

locating central points on a surface overlying the individual thin-film head devices; and

controlling step width, depth, and number in the stair-step etching operation to variably set a radius of curvature of the bumps.

4. A method according to claim 1 further comprising:

stair-step etching the head structure so that the individual thin-film head devices have the form of raised bumps with a structure selected from among a plurality of structures including circularly symmetric, elliptically symmetric, square, rectangular, polygonal, and asymmetric structures.

5. A method according to claim 1 further comprising:

stair-step etching the head structure using an ion milling procedure.

6. A method according to claim 1 further comprising:

stair-step etching the head structure using a wet etch procedure.

7. A thin film processing method comprising:

fabricating a finished thin film substrate including a plurality of thin film magnetic heads, the magnetic thin-film heads being raised relative to a planar surface of the thin film substrate, the raised thin-film heads including a magnetic yoke, a coil encircling the magnetic yoke, magnetic poles coupled at polar ends of the magnetic yoke, the magnetic poles being separated by a gap, and an insulating frame encasing and mutually insulating the magnetic yoke and the coil, the magnetic yoke and coil being centrally-located within an individual thin-film head;

stair-step etching the insulating frame of the individual thin-film heads so that the centrally-located magnetic yoke and coil underlie a raised portion of the insulating frame and portions of the individual thin-film heads lateral to the magnetic yoke and coil are etched to form depressions between the individual thin-film heads; and

chemical mechanical contouring (CMC) the thin film substrate subsequent to the fabrication step to form a substantially smooth, curved surface overlying the individual thin film magnetic heads.

8. A method according to claim 7 further comprising:

stair-step etching the insulating frame by locating a central point of an individual thin-film head, etching a sequence of stair-steps surrounding the central point, and controlling the width and depth of the stair-step etches as a function of distance from the central point.

9. A method according to claim 7 further comprising:

locating central points on a surface overlying the individual thin-film heads; and

controlling step width, depth, and number in the stair-step etching operation to variably set a radius of curvature of the individual thin-film heads.

10. A method according to claim 7 further comprising:

stair-step etching the insulating frame so that the individual thin-film heads have the form of raised bumps with a structure selected from among a plurality of structures including circularly symmetric, elliptically symmetric, square, rectangular, polygonal, and asymmetric structures.

11. A method according to claim 7 further comprising:

stair-step etching the insulating frame using an ion milling procedure.

12. A method according to claim 7 further comprising:

stair-step etching the insulating frame using a wet etch procedure.

13. A method of forming a smooth surface on a thin-film structure comprising:

selecting a width and depth of stair-step etching;

stair-step etching the thin-film structure according to the selected width and depth; and

chemical-mechanical contouring (CMC) the stair-step etched thin-film structure to smooth edges formed by the stair-step etching process, the height and width of the stair-steps selected to attain a predetermined shape and size of bumps formed on the thin-film structure surface.