Servo pattern characterization on magnetic disks
AssigneeKLA-Tencor Technologies Corporation
InventorsZhen Hou, Ronny Soetarman, Vamsi Velidandla, Steven W. Meeks
Life of this patent
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Abstract
In one embodiment, a surface analyzer system comprises a radiation targeting assembly to target radiation onto a surface, a reflected radiation collecting assembly that collects radiation reflected from the surface, and a signal processing module. The signal processing module generates an image of magnetic characteristics of the magnetic disk, wherein the image comprises a plurality of servo sector arcs, locates a sample of points on a plurality of the servo sector arcs, fits a circle to the sample of points on each of the plurality of servo sector arcs, and determines at least one pivot-to-gap measurement from the radius of the circles.
Claims17
A method of characterizing a servo pattern on a magnetic disk, comprising:
- acquiring an image of magnetic characteristics of the magnetic disk, wherein the image comprises a plurality of servo sector arcs;
- locating a sample of points on a plurality of the servo sector arcs;
- fitting a circle to the sample of points on each of the plurality of servo sector arcs;
- determining at least one pivot-to-gap measurement from the radius of the circles, wherein locating a sample of points on a plurality of the servo sector arcs comprises:
- selecting a plurality of sample track data from the magnetic disk;
- applying a smoothing function to the sample track data;
- applying a flattening function to the sample track data;
- and
- locating local minimums in the sample track data.
A surface analyzer system, comprising:
- a radiation targeting assembly to target radiation onto a surface;
- and
- a reflected radiation collecting assembly that collects radiation reflected from the surface;
- and
- a signal processing module to:
- generate an image of magnetic characteristics of the magnetic disk, wherein the image comprises a plurality of servo sector arcs;
- locate a sample of points on a plurality of the servo sector arcs;
- fit a circle to the sample of points on each of the plurality of servo sector arcs;
- and
- determine at least one pivot-to-gap measurement from the radius of the circles;
- select a plurality of sample track data from the magnetic disk;
- apply a smoothing function to the sample track data;
- apply a flattening function to the sample track data;
- and
- locate local minimums in the sample track data.
A computer program product comprising logic instructions stored on a computer-readable medium which, when executed, configure a processor to:
- analyze an image of magnetic characteristics of the magnetic disk, wherein the image comprises a plurality of servo sector arcs;
- locate a sample of points on a plurality of the servo sector arcs;
- fit a circle to the sample of points on each of the plurality of servo sector arcs;
- determine at least one pivot-to-gap measurement from the radius of the circles;
- select a plurality of sample track data from the magnetic disk;
- apply a smoothing function to the sample track data;
- apply a flattening function to the sample track data;
- and
- locate local minimums in the sample track data.
A surface analyzer system, comprising:
- a radiation targeting assembly to target radiation onto a surface of a magnetic disk;
- and
- a reflected radiation collecting assembly that collects radiation reflected from the surface;
- and
- a signal processing module to determine a distance between a center of one or more circles defined by a magnetic pattern on the magnetic disk and a magnetic center of the disk from an image of magnetic characteristics of the magnetic disk;
- wherein the signal processing module:
- selects a plurality of sample track data from the magnetic disk;
- applies a smoothing function to the sample track data;
- applies a flattening function to the sample track data;
- and
- locates local minimums in the sample track data.
Dependencies are inferred from the claim text.