Method of making a bi-level coil for a thin film magnetic transducer

• US 5,472,736 A
• Filed: 03/20/1995
• Issued: 12/05/1995
• Est. Priority Date: 06/03/1991
• Status: Expired due to Term

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Read-Rite Corporation (Western Digital Corporation)
• Inventors: Hagen, Jeffrey P., Barr, Ronald A.
• Primary Examiner(s): Utech, Benjamin
• Application Number:
  US08/407,270
• Time in Patent Office: 260 Days
• Field of Search: 427/123, 427/130, 427/131, 427/132, 427/282, 427/307, 427/404, 430/97
• US Class Current: 427/123
• CPC Class Codes: G11B 5/313 Disposition of layers
• CPC Class Codes: H05K 1/165 incorporating printed inductors
• CPC Class Codes: H05K 2201/09736 Varying thickness of a single conductor; Conductors in the same plane having different thicknesses
• CPC Class Codes: H05K 2203/0574 Stacked resist layers used for different processes
• CPC Class Codes: H05K 3/243 characterised by selective plating, e.g. for finish plating of pads selective plating for making the circuit pattern H05K3/108, H05K3/182

Abstract

A method of manufacturing a thin film magnetic transducer in which a layer of photoresist material is used to pattern the turns of a bi-level electrical coil. The thickness of the photoresist layer is increased to the maximum height of the bi-level coil. A multi-turn spiral type rectangular trench is formed to define the pattern of the coil structure. In the first coil plating step, a first coil section is plated in the trench to approximately the midpoint of its height. The layer of the resist material is then cured and a blocking mask is deposited over the portion of the first coil section that is not to be further increased in height. The area of the coil that is not blocked by the blocking mask is again plated using the initial pattern until each partial turn in the unblocked section reaches the top of the groove. The cured resist material and the blocking mask are then removed. Since both plating steps rely on the same pattern that has been formed in the photoresist material, alignment errors and mask tolerance problems experienced with prior art methods are virtually eliminated, thereby resulting in substantially higher yields and lower manufacturing costs.

Claims

1. A method of making a bi-level coil structure for a thin film magnetic transducer comprising the steps of:

depositing photoresist material on a base to a level that defines a height of said bi-level coil structure;

forming a patterned groove in said photoresist material, said patterned groove having a depth substantially equal to said height of said bi-level coil structure;

depositing a coil by plating conductive material in said groove to a level about the midpoint of the depth of said groove;

curing said photoresist material;

locating a blocking mask over a portion of said deposited coil, so that another portion of said deposited coil remains exposed;

plating a conductive material over the exposed portion of said deposited coil to a level substantially at the top of said groove so that said bi-level coil structure is formed as a continuous single coil of varying thickness; and

depositing insulation material over said bi-level coil structure.

2. A method of manufacturing a bi-level electrical coil disposed between first and second magnetic layers of a magnetic yoke in a thin film magnetic transducer comprising the steps of:

depositing a layer of photoresist material to a level that defines a height of said bi-level coil, after forming said first magnetic layer of said magnetic yoke and depositing an insulating layer thereover;

patterning a first coil section on said photoresist layer including the step of defining a trench in said photoresist layer by dissolving portions of said photoresist, said trench having a depth substantially equal to said height of said bi-level coil;

plating the patterned first coil section in said trench to a level less than the depth of said trench;

curing said photoresist material that defines said trench;

depositing a masking layer over a portion of said trench which contains said first coil section, and exposing another portion of said trench;

plating a patterned second coil section over the exposed portion of said trench until the height of said second coil section is at a level that substantially coincides with the top of said trench, said first and second coil sections forming a continuous coil structure of varying thickness;

dissolving the cured photoresist to expose said bi-level coil structure;

depositing said second magnetic layer above said coil sections with insulation between said magnetic layer and said coil sections.