Double winding twin coil for thin-film head writer
View Patent ↗An enhanced inductive coil design for use in data storage magnetic disk drives with areal density over 35 Gb/in 2 , features a double wound twin coil that is able to achieve a yoke length of 15 μm or less by reducing the insulation spacing between the two coils. The coil further presents improved reliability by reducing the possibility of occurrence of electrical shorting. The coil is made by forming two interleafing conductors on the same layer with a demesne process. A tri-level process is implemented in the layout of the first conductor to ensure that the coil width and spacing are uniform and even, in order for the second conductor to be wound therebetween. A conformal dielectric layer of approximately 0.1 to 0.2 μm in thickness is deposited between the two conductors and serves as insulation. The two conductors are formed by a copper seed layer plating process that eliminates potential damage to the conductors during production.
1. An inductive coil for use in a write head of a data storage system, comprising:
first coil elements that are formed over a stopping layer, said first coil elements having a metallic composition and being separated by spaces;
an insulation layer formed on the first coil elements and within the spaces;
second coil elements that are formed within the spaces, said second coil elements having a metallic composition;
each of the first and second coil elements having a top surface; and
wherein the first and second coil elements are arranged in an alternating horizontal arrangement so that the top surfaces of the first and second coil elements are substantially horizontally co-planar.
2. The coil of claim 1 , wherein the insulation layer is formed by a plasma enhanced chemical vapor deposition process.
3. The coil of claim 1 , wherein the metallic composition of the first coil elements is inert relative to a reactive ion etching process used to remove at least a portion of the insulation layer.
4. The coil of claim 1 , wherein the second coil elements are formed by a plating process.
5. The coil of claim 4 , wherein the second coil elements are further formed by a deposition process.
6. The coil of claim 1 , wherein each of the first coil elements and the second coil elements has a generally rectangularly shaped cross-section.
7. The coil of claim 1 , wherein each of the first coil elements and the second coil elements has a generally trapezoidally shaped cross-section.
8. The coil of claim 1 , further comprising a protective insulating layer that encapsulates the first coil elements, and the second coil elements.
9. The coil of claim 8 , wherein the protective insulating layer is made of any of photoresist material, alumina, or silicon dioxide.
10. The coil of claim 1 , that is topologically divided into a front region, a central region, and an aft region.
11. The coil of claim 10 , wherein the first and second coil elements are generally flattened in the front region.
12. The coil of claim 11 , wherein the first and second coil elements are reduced to a minimal width in the front region to reduce the coil size.
13. The coil of claim 12 , wherein the central region is generally made of a dielectric material and provides physical separation between the front region and aft region for magnetic induction during a write operation.
14. The coil of claim 13 , wherein the first coil elements and the second coil elements are spirally wound starting from the front region and terminating in the aft region.
15. The coil of claim 14 , wherein each of the first and second coil elements has a width that varies between approximately 1.0 μm in the front region to approximately 3.0 μm in the aft region.
16. The coil of claim 1 , further comprising an interconnect that connects a terminal end of the first coil elements to a terminal end of the second coil elements, so that the first and second coil elements form an integral coil.
17. A write head comprising an inductive coil for use in a data storage system, the inductive coil comprising:
first coil elements that are formed over a stopping layer, said first coil elements having a metallic composition and being separated by spaces;
an insulation layer formed on the first coil elements and within the spaces;
second coil elements that are formed within the spaces, said second coil elements having a metallic composition;
each of said first and second coil elements having a top surface; and
wherein the first and second coil elements are arranged in an alternating horizontal arrangement so that the top surfaces of the first and second coil elements are substantially horizontally co-planar.
18. The write head of claim 17 , wherein the insulation layer is formed by a plasma enhanced chemical vapor deposition process.
19. The write head of claim 17 , wherein the metallic composition of the first coil elements is inert relative to a reactive ion etching process used to remove at least a portion of the insulation layer.
20. The write head of claim 17 , wherein the second coil elements are formed by a plating process.
21. The write head of claim 20 , wherein the second coil elements are further formed by a deposition process.
22. The write head of claim 17 , wherein each of the first coil elements and the second coil elements has a generally rectangularly shaped cross-section.
23. The write head of claim 17 , wherein each of the first coil elements and the second coil elements has a generally trapezoidally shaped cross-section.
24. The write head of claim 17 , further comprising a protective insulating layer that encapsulates the first coil elements, and the second coil elements.
25. The write head of claim 24 , wherein the protective insulating layer is made of any of photoresist material, alumina, or silicon dioxide.
26. The write head of claim 17 , that is topologically divided into a front region, a central region, and an aft region.
27. The write head of claim 26 , wherein the first and second coil elements are generally flattened in the front region.
28. The write head of claim 27 , wherein the first and second coil elements are reduced to a minimal width in the front region to reduce the coil size.
29. The write head of claim 28 , wherein the central region is generally made of a dielectric material and provides physical separation between the front region and aft region for magnetic induction during a write operation.
30. The write head of claim 29 , wherein the first coil elements and the second coil elements are spirally wound starting from the front region and terminating in the aft region.
31. The write head of claim 30 , wherein each of the first and second coil elements has a width between approximately
1.0 μm in the front region to approximately 3.0 μm in the aft region.
32. The write head of claim 17 , further comprising an interconnect that connects a first terminal end of at least one of the first coil elements to a second terminal end of at least one of the second coil elements, so that the first and second coil elements form at least one integral coil.