Self-aligned coil process in magnetic recording heads
In one embodiment of the present invention, a write head includes a first pole P1, a P1 pedestal, a first back gap layer plated on top of the first pole P1 leaving a region between the P1 pedestal and the first back gap layer for plating a coil, a first insulation layer applied on top of the P1 pedestal and the first back gap layer and the region between the P1 pedestal and the first back gap layer. The write head further includes a coil, patterned at least partially on top of the P1 pedestal and the first back gap layer and the region between the P1 pedestal and the first back gap layer, copper plated in the coil patterns, and a second insulation layer applied to fill the spaces in between the coil turns. The resulting structure is planarized via chemical mechanical polishing.
This application is a continuation-in-part of prior U.S. patent application Ser. No. 10/652,878, filed on Aug. 29, 2003, entitled “Method For Patterning A Self-Aligned Coil Using A Damascene Process”, the disclosure of which is incorporated herein by reference, as though set forth in full.
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention relates generally to the field of magnetic recording heads having coils inducing magnetic flux for writing on a magnetic medium (such as a magnetic disc) and more particularly, to recording heads having coils that are self-aligned and with low resistance yet utilizing conventional processing techniques for manufacturing thereof.
2. Description of the Prior Art
Magnetic hard drives (or disc drives) have been in common use for storage of large groups of data for decades. Improvements in manufacturing thereof have attracted popular attention particularly to reducing the size of the drive and/or its internal components to achieve both lower costs and wider applications.
Magnetic hard drives include magnetic recording head for reading and writing of data. As well known, a magnetic recording head generally includes two portions, a write head portion or head for writing or programming magnetically-encoded information on a magnetic media or disc and a reader portion for reading or retrieving the stored information from the media.
Data is written onto a disc by a write head that includes a magnetic yoke having a coil passing there through. When current flows through the coil, a magnetic flux is induced in the yoke, which causes a magnetic field to fringe out at a write gap in a pole tip region. It is this magnetic field that writes data, in the form of magnetic transitions, onto the disk. Currently, such heads are thin film magnetic heads, constructed using material deposition techniques such as sputtering and electroplating, along with photolithographic techniques and wet and dry etching techniques.
Examples of such thin film heads include a first and second magnetic poles connected through a back gap forming a horseshoe structure and having a pole tip region and a back gap region, formed of a material such as NiFe which might be plated onto a substrate after sputter depositing an electrically conductive seed layer. Opposite the pole tip region, at a back end of the magnetic pole, a magnetic back gap can be formed. A back gap is the term generally used to describe a magnetic structure that magnetically connects the first and second poles to form a completed magnetic yoke as will be described.
One or more electrically conductive coils can be formed over the first pole, between a pedestal, positioned above a portion of the first pole, and the back gap and can be electrically isolated from the pole and yoke by an insulation layer, which could be alumina (Al2O3) or hard baked photoresist.
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The pole tip region 413, the P3 magnetic layer 438 and the back gap 414 form the magnetic yoke (or yoke) referred to in the foregoing and below. It is desirable to maintain a short yoke length to keep the magnetic path short and thus to minimize magnetic leakage and to achieve high data rate for better performance. It is through the write gap 424 that the field 310 (in
In the prior art write head 400, the P2 pole tip 430 is shown residing below the P3 magnetic layer 438 and in fact, connected thereto. In other prior art write heads, the P2 pole tip 430 extends all the way across forming a P2 layer without the P3 magnetic layer 438.
As those skilled in the art will appreciate, the coil 418 and the second coil 434 are critical elements of the write or recording head because they form the coil 304 of
Therefore, the need arises for a write head of a disc drive to have a coil wide or thick enough to have low resistance and manufactured to be self-aligned to avoid protrusion of the write head yet manufactured using the same tools as used in manufacturing prior art write heads.
SUMMARY OF THE INVENTIONBriefly, in one embodiment of the present invention, a write head includes a first pole P1, a P1 pedestal (P1P) and, a first back gap layer plated on top of the first pole P1 leaving a region between the P1 pedestal and the first back gap layer for plating a coil, a first insulation layer applied on top of the P1 pedestal and the first back gap layer and the region between the P1 pedestal and the first back gap layer. The write head further includes a coil, patterned at least partially on top of the P1 pedestal and the first back gap layer and the region between the P1 pedestal and the first back gap layer, copper plated in the coil patterns, and a second insulation layer applied to fill the spaces in between the coil turns. The resulting structure is planarized via chemical mechanical polishing.
IN THE DRAWINGS
FIGS. 6(a)-(i) show some of the relevant steps for processing or manufacturing of the write head 508 of
FIGS. 7(a)-(f) show additional steps needed to complete the fabrication of the write head 508.
FIGS. 8(a)-(f) show the relevant steps for an alternative method for fabrication of the coil 624.
FIGS. 9(a), (b) and (c) show alternative steps in manufacturing the write head 508.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTThe following description is an embodiment presently contemplated for carrying out this invention. This description is made for the purpose of illustrating the general principles of this invention and is not meant to limit the inventive concepts claimed herein.
Referring now to
During operation of the disc drive 100, rotation of the disc 116 generates an air cushion which is encountered by the slider 111. This air cushion acts to keep the slider 111 afloat a small distance above the surface of the disc 116, allowing the slider 111 to fly above the surface of the disc 116. The VCM 102 is selectively operated to move the actuator arm 104 around the axis 120, thereby moving the suspension 106 and positioning the transducing head (not shown), which includes a main pole (not shown), by the slider 111 over the tracks 118 of the disc 116. It is imperative to position the transducing head properly to read and write data from and to the concentric tracks 118.
With reference now to
At least one slider 111 is positioned near the magnetic disc 116, each slider 111 supporting one or more magnetic head assemblies 221. As the magnetic disc rotates, the slider 111 is moved radially in and out over the disc surface 222 so that the magnetic head assembly 221 may access different tracks of the magnetic disc where desired data are written. Each slider 111 is attached to the actuator arm 104 by way of a suspension 106. The suspension 106 provides a slight spring force which biases slider 111 against the disc surface 222. Each actuator arm 104 is attached to an actuator means 227. The actuator means 227, as shown in
During operation of the disc storage system or disc drive 100, the rotation of the disc 116 generates an air bearing between the slider 111 and the disc surface 222 which exerts an upward force or lift on the slider. The air bearing thus counter-balances the slight spring force of the suspension 106 and supports the slider 111 off and slightly above the disc surface by a small, substantially constant spacing during normal operation.
The various components of the disc storage system are controlled in operation by control signals generated by the control unit 229, such as access control signals and internal clock signals. Typically, the control unit 229 comprises logic control circuits, storage means and a microprocessor. The control unit 229 generates control signals to control various system operations such as drive motor control signals on line 223 and head position and seek control signals on line 228. The control signals on line 228 provide the desired current profiles to optimally move and position slider 111 to the desired data track on the disc 116. Write and read signals are communicated to and from write and read heads 221 by way of recording channel 225.
The above description of a typical magnetic disk storage system and the accompanying illustration of
This invention provides a new structure as well as a method of improving the fabrication of a portion of the write head. With reference to
The read head 501 is shown to include magnetic read element 502 sandwiched between first and second magnetic shields, 504 and 506. A write head, generally referred to as 508, includes a first pole P1 510. A P1 pedestal 512 disposed at the air bearing surface (ABS) 526 and a first back gap layer 514, at an opposite end, are formed over the first pole. The first pole 510, P1 pedestal 512, and back gap 514 are formed of a magnetic material such as for example NiFe. A first coil insulation layer 516 is formed over the first pole 510 between the P1 pedestal 512 and the back gap layer 514. In one method of manufacturing the write head 500, the back gap layer 514 is made at the same time as the P1 pedestal 512. However, in other methods of manufacturing the same, the back gap layer 514 is made separately. In one embodiment of the present invention, the back gap layer 514 may be made of nickel iron (NiFe) alloys, cobolt iron (CoFe) alloys, or cobolt iron nickel (CoFeNi) alloys. An electrically conductive coil layer 518, shown in partial cross section in
In one embodiment of the present invention, the first insulation layer 516 is made by the deposition of a layer of alumina (Al2O3) or silicon dioxide (SiO2) followed by the deposition of a seed layer (e.g. Rhodium), and the coil 518 is made of copper. A second coil insulation layer 520 insulates the turns of the coil 518 from one another and insulates the coil from the rest of the write head 508. In one embodiment of the present invention, the second coil insulation layer 520 is hard baked photoresist.
The embodiment of
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Another advantage of an embodiment according to the present invention is based on the fact that the protrusion of the magnetic poles and shields at the ABS is reduced in an embodiment of the present invention because the write head is cooler during write operations. Protrusion is reduced by packing more copper versus insulation material into the area between the P1 pedestal 512 and the back gap 514 (area into which copper is plated). As current is applied into the coil, protrusion is reduced if more copper is packed into the coil pocket. Based on ohm's law, resistance is inversely proportional to the copper thickness. Therefore, an increase in the coil line width results in lower resistance that leads to lower heat generation and therefore reduced protrusion.
Moreover, the same tools and processes that are utilized to manufacture the write head 408 of
For example, as a comparison to the use of damascene process, the latter uses photolithography tool, reactive ion etch tool, copper plating tool and CMP tool to form the coil. The non-damascene coil process of the present invention only uses photolithography tool and copper plating tool.
The coil 518, illustrated in
The coil 518 of
Remaining figures will now be discussed to provide further details of the steps for manufacturing the write head 508.
FIGS. 6(a)-(i) show some of the relevant steps for processing or manufacturing the write head 508. In
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FIGS. 7(a)-(f) show additional steps performed to complete the fabrication of the write head 508, and will be discussed briefly. In
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FIGS. 8(a)-(f) are presented for a better understanding of an alternative method for fabrication of the coil 624 shown in FIGS. 9(a)-(c), which will now be discussed. Steps 608 and 610 of FIGS. 8(a) and (b) are performed, as previously discussed relative to FIGS. 6(d) and 6(e), respectively. However, next, rather than performing step 612, step 651 of
Although the present invention has been described in terms of specific embodiments, it is anticipated that alterations and modifications thereof will no doubt become apparent to those skilled in the art. It is therefore intended that the following claims be interpreted as covering all such alterations and modification as fall within the true spirit and scope of the invention.
Claims
1. A method of manufacturing a write head comprising:
- forming a P1 pedestal and a first back gap layer on top of a first pole P1 leaving a region therebetween for forming a coil, the first back gap layer formed at a distal end of the first pole P1;
- depositing a first insulation layer disposed over at least a portion of the P1 pedestal, the first pole P1 and the first back gap layer and the region;
- forming a coil by depositing copper in coil pockets formed in a coil photoresist layer deposited over the first insulation layer, wherein the coil has multiple turns;
- removing the coil photoresist layer to form spaces in between the coil turns; and
- applying a second insulation layer to fill the spaces in between the coil turns.
2. A method of manufacturing as recited in claim 1, further comprising:
- removing excess deposited coil and photoresist layer to form a planar surface.
3. A method of manufacturing as recited in claim 1, further comprising:
- removing a coil seed layer before applying the second insulation layer, wherein the coil seed layer was deposited before applying the coil photoresist layer.
4. A method of manufacturing as recited in claim 1 wherein the first insulation layer is made of alumina.
5. A method of manufacturing as recited in claim 2 wherein the thickness of the first insulation layer behind the P1 pedestal is in the range of 0.1 to 0.5 microns.
6. A method of manufacturing as recited in claim 1 wherein the coil is made of copper.
7. A method of manufacturing as recited in claim 1 wherein the thickness of each of the coil turns is in the range of 0.5 to 4 microns.
8. A method of manufacturing as recited in claim 1 wherein the coil is self-aligned with respect to the P1 pedestal.
9. A method of manufacturing as recited in claim 1 wherein after the step of applying a second insulation layer, performing the step of hard baking to encapsulate the coil.
10. A method of manufacturing as recited in claim 9 further including the step of:
- depositing alumina over the hard baked resist; and
- performing a chemical mechanical polishing (CMP) process.
11. A method of manufacturing as recited in claim 1 further including the steps of:
- depositing a write gap on top of the alumina after the chemical mechanical polishing step of claim 10;
- forming a P2 pole tip on top of the write gap and at opposite end, a second back gap on top of the first back gap;
- depositing alumina on the P2 pole tip and the second back gap layer;
- performing CMP process;
- forming a second coil layer;
- applying a third insulation layer on top of the second coil layer; and
- forming a P3 magnetic layer on top of the second coil layer extending from the P2 pole tip to the second back gap layer.
12. A structure formed in a write head comprising:
- a first pole P1;
- a P1 pedestal formed on top of the first pole P1;
- a first back gap layer plated on top of the first pole P1 leaving a region between the P1 pedestal and the first back gap layer for forming a coil;
- a first insulation layer applied on top of the P1 pedestal, P1 pole and the region between the P1 pedestal and the first back gap layer;
- coil turns defined by a coil pattern that is self-aligned on top of the P1 pedestal and the first back gap layer and the region between the P1 pedestal and the first back gap layer, wherein the coil turns are formed in the coil patterns with spaces formed in between the coil turns; and
- a second insulation layer applied to fill the spaces in between the coil turns.
13. A structure as recited in claim 10 further including a first insulation layer applied to the P1 pedestal.
14. A structure as recited in claim 11 wherein the first insulation layer is made of Al2O3.
15. A structure as recited in claim 12 wherein the thickness of the first insulation layer behind the P1 pedestal is in the range of 0.1 to 0.5 microns.
16. A structure as recited in claim 12 wherein the thickness of the first insulation layer in front of the back gap is in the range of 0.1 to 0.5 microns.
17. A structure as recited in claim 12 wherein the thickness of each of the coil turns is in the range of 0.5 to 4 microns.
18. A structure as recited in claim 10 wherein the coil is self-aligned.
19. A disc drive comprising:
- a write head including,
- a first pole P1;
- a P1 pedestal;
- a first back gap layer plated on top of the first pole P1 leaving a region between the P1 pedestal and the first back gap layer for forming a coil;
- a first insulation layer applied on top of the P1 pedestal and the region between the P1 pedestal and the first back gap layer;
- coil pattern, defined by coil turns, self-aligned on top of the P1 pedestal and the first back gap layer and the region between the P1 pedestal and the first back gap layer, wherein the coil turns are formed in the coil patterns with spaces formed in between the coil turns; and
- a second insulation layer applied to fill the spaces in between the coil turns.
20. A writer comprising:
- a first pole pedestal formed over a first end of a first pole;
- a first back gap layer formed over second end of the first pole;
- a first insulation layer at least partially covering the first pole pedestal and the back gap;
- a first seed layer at least partially covering the first pole pedestal and the back gap;
- coil patterns formed on top of the first seed layer; and
- self-aligned coil plated into the coil patterns.
21. A writer, as recited in claim 18, wherein the coil is encapsulated.
22. A writer as recited in claim 18 including a self-aligned second coil formed on top of a dielectric fill layer, the dielectric fill layer formed on top the pedestal and the back gap.
23. A structure formed in a write head comprising:
- a first pole P1;
- a P1 pedestal formed on top of the first pole P1;
- a first back gap layer plated on top of the first pole P1 leaving a region between the P1 pedestal and the first back gap layer for plating a coil;
- a first insulation layer applied on top of the P1 pedestal and the region between the P1 pedestal and the first back gap layer;
- coil turns defined by a coil pattern formed on top of the region between the P1 pedestal and the first back gap layer wherein the coil turns are formed in the coil patterns with spaces formed in between the coil turns; and
- a second insulation layer applied to fill the spaces in between the coil turns, the conductivity of the area defined below the second insulation layer and above the first pole P1 and extending between the P1 pedestal and the first back gap layer increasing by 20 to 40%.
24. A structure as recited in claim 23 further including a first insulation layer applied to the P1 pedestal.
25. A structure as recited in claim 24 wherein the first insulation layer is made of Al2O3.
26. A structure as recited in claim 24 wherein the thickness of the first insulation layer behind the P1 pedestal is within the range of 0.1 to 0.5 microns.
27. A structure as recited in claim 24 wherein the thickness of the first insulation layer in front of the back gap is within the range of 0.1 to 0.5 microns.
28. A structure as recited in claim 23 wherein the thickness of each of the coil turns is in the range of 0.5 to 4 microns.
29. A structure as recited in claim 23 wherein the coil is self-aligned.
Type: Application
Filed: Oct 4, 2005
Publication Date: Feb 16, 2006
Inventors: Terence Lam (Cupertino, CA), David Lee (San Jose, CA), Edward Lee (San Jose, CA), Changqing Shi (San Jose, CA)
Application Number: 11/243,731
International Classification: B44C 1/22 (20060101); G11B 5/127 (20060101); G11B 5/147 (20060101); G11B 5/33 (20060101);