Method for fabricating a magnetic writer having half-side shields

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to provisional U.S. Patent Application Ser. No. 61/946,564, filed on Feb. 28, 2014, which is hereby incorporated by reference in its entirety.

BACKGROUND

FIG. 1 depicts an air-bearing surface (ABS) view of a conventional magnetic recording transducer 10. The magnetic recording transducer 10 may be a perpendicular magnetic recording (PMR) head. The conventional transducer 10 includes an underlayer 12, side gap 14, side shields 16, top gap 17, optional top, or trailing, shield 18 and main pole 20.

The main pole 20 resides on an underlayer 12 and includes sidewalls 22 and 24. The sidewalls 22 and 24 of the conventional main pole 20 form an angle α0 with the down track direction at the ABS. The side shields 16 are separated from the main pole 20 by a side gap 14. The side shields 16 extend at least from the top of the main pole 20 to the bottom of the main pole 20. The side shields 16 also extend a distance back from the ABS. The gap 14 between the side shields 16 and the main pole 20 may have a substantially constant thickness. Thus, the side shields 16 are conformal with the main pole 20.

Although the conventional magnetic recording head 10 functions, there are drawbacks. In particular, the conventional magnetic recording head 10 may not perform sufficiently at higher recording densities. For example, at higher recording densities, a shingle recording scheme may be desired to be sued. In shingle recording, successive tracks partially overwrite previously written tracks in one direction only. Part of the overwritten tracks, such as their edges, are preserved as the recorded data. In shingle recording, the size of the main pole 20 may be increased for a given track size. However, in order to mitigate issues such as track edge curvature, shingle writers have very narrow side gaps 14. Other design requirements may also be present. The magnetic transducer 10 may not perform as desired or meet the design requirements for such recording schemes. Without such recording schemes, the conventional transducer 10 may not adequately perform at higher areal densities. Accordingly, what is needed is a system and method for improving the performance of a magnetic recording head.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 depicts an ABS view of a conventional magnetic recording head.

FIG. 2 depicts a flow chart of an exemplary embodiment of a method for providing a magnetic recording transducer having a half side shield.

FIGS. 3A, 3B, 3C and 3D depict side, ABS, yoke and apex views of an exemplary embodiment of a magnetic recording disk drive.

FIG. 4 depicts a flow chart of another exemplary embodiment of a method for providing a magnetic recording transducer having half side shields.

FIGS. 5A, 5B and 5C through 19A, 19B, 19C and 19D depict various views of an exemplary embodiment of a magnetic recording transducer fabricated using the method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2 depicts an exemplary embodiment of a method 100 for providing a magnetic recording transducer. For simplicity, some steps may be omitted, interleaved, combined and/or performed in another order. The method 100 is described in the context of providing a magnetic recording disk drive and transducer 200. However, the method 100 may be used to fabricate multiple magnetic recording transducers at substantially the same time. The method 100 is also described in the context of particular layers. A particular layer may include multiple materials and/or multiple sub-layers. The method 100 also may start after formation of other portions of the magnetic recording head. For example, the method 100 may start after a read transducer, return pole/shield and/or other structure have been fabricated.

An intermediate layer including at least two sublayers is provided, via step 102. In at least the region in which the side shields are to be formed (shield region), the intermediate layer includes a first sublayer and a second sublayer. The first and second sublayer may be removed using different processes. The second sublayer is on the first sublayer. In some embodiments, the first sublayer includes silicon oxide, while the second sublayer includes aluminum oxide. A third sublayer may be outside of the shield region. However, the top of the third sublayer is desired to be substantially coplanar with the top of the second sublayer. Stated differently, the top of the intermediate layer is desired to be substantially flat so that fabrication may take place with less variations in topography of the intermediate layer. In some embodiments, the third sublayer may be formed of the same material as the first sublayer. Thus, the third sublayer may include silicon oxide. The first sublayer may thus be considered part of the first sublayer whether the first and third sublayers are formed separately or together. In some embodiments, step 102 includes full-film depositing first and second layers, then removing the portions of these layers outside of the side shield region. The first and second sublayers thus remain in the side shield region. The third sublayer may then be deposited and the layer(s) planarized. Thus, the intermediate layer may be formed.

A trench is formed in an intermediate layer using one or more etches, via step 104. The trench formed has the desired geometry and location for formation of the main pole. For example, the top of the trench may be wider than the bottom so that the top of the main pole may be wider than the bottom. The sidewall angles may also vary. For example, the sidewall angles at and near the ABS may be larger (further from perpendicular to the surface of the intermediate layer) than the sidewall angles in regions recessed from the ABS (termed the yoke herein). For example, the sidewalls may be substantially perpendicular to the bottom of the trench in the yoke region, but twelve to sixteen degrees from the down track direction near the ABS. In other embodiments, other sidewall angles and/or other variations in sidewall angles may be possible. In some embodiments, step 104 controls the sidewall angles through the use of multiple etches and/or etch conditions for each etch. Further, the trench extends at least partially into the first sublayer in the shield region. In some embodiments, some or all of the trench may extend through the first sublayer. Thus, the top of the first sublayer resides between the bottom and the top of the trench.

The main pole is provided in the trench, via step 106. In some embodiments, step 106 includes depositing a seed layer, such as Ru and/or magnetic seed layer(s). High saturation magnetization magnetic material(s) are also provided. For example, such magnetic materials may be plated and/or vacuum deposited. The pole formed in step 106 may be conformal to the trench, nonconformal with the trench, or include both conformal and nonconformal portions. The top of the first sublayer is between the bottom of the main pole and the top of the main pole in the shield region.

At least part of the second sublayer in the shield region is removed, via step 108. Step 108 may be performed using a wet etch appropriate for the second sublayer, but not the first or third sublayers.

The side shield(s) are provided in the shield region, via step 110. Step 110 may include plating or otherwise providing the material(s) for the side shields. The bottoms of the side shields reside on the top of the first sublayer in the shield region. Thus, the side shield(s) extend to a location between the top and the bottom of the main pole. The side shields are thus termed half side shields. Note, however, that the half shields need not extend precisely halfway down between the top and bottom of the main pole. Instead, the half side shields terminate somewhere between the top and bottom of the main pole.

Using the method 100, a magnetic transducer having improved performance may be fabricated. A shingle writer may not need to have side shield(s) which extend to the bottom of the main pole. Thus, the method 100 may provide a main pole that may be used in shingle recording. Thus, the benefits of shingle recording may be exploited. The location of the bottom of the half side shields may be set by the thickness of the first sublayer. Thus, the side shield geometry may be predefined. As such, the method 100 may be simplified.

FIGS. 3A, 3B, 3C and 3D depict various views of a transducer 200 fabricated using the method 100. FIG. 3A depicts a side view of the disk drive. FIGS. 3B and 3C depict AS and yoke views of the transducer 200. FIG. 3D depicts an apex (side/cross-sectional) view of the transducer 200. The “yoke” view shown in FIG. 3C is taken at location x1 shown in FIG. 3D. For clarity, FIGS. 3A-3D are not to scale. For simplicity not all portions of the disk drive and transducer 200 are shown. In addition, although the disk drive and transducer 200 are depicted in the context of particular components other and/or different components may be used. For example, circuitry used to drive and control various portions of the disk drive is not shown. For simplicity, only single components are shown. However, multiples of each components and/or their sub-components, might be used. The disk drive 100 may be a perpendicular magnetic recording (PMR) disk drive. However, in other embodiments, the disk drive 100 may be configured for other types of magnetic recording included but not limited to heat assisted magnetic recording (HAMR).

The disk drive includes a media 202, and a slider 204 on which a transducer 200 have been fabricated. Although not shown, the slider 204 and thus the transducer 200 are generally attached to a suspension. In general, the slider 204 includes the write transducer 200 and a read transducer (not shown). However, for clarity, only the write transducer 200 is shown.

The transducer 200 includes an underlayer 206, an intermediate layer 208, a main pole 210, coil(s) 220 and half shields 230. The underlayer 206 may include a bottom (or leading edge) shield. The coil(s) 220 are used to energize the main pole 210. Two turns are depicted in FIG. 3A. Another number of turns may, however, be used. Note that only a portion of the coil(s) 210 may be shown in FIG. 3A. If, for example, the coil(s) 220 is a spiral, or pancake, coil, then additional portions of the coil(s) 220 may be located further from the ABS. Further, additional coils may also be used.

The intermediate layer 208 may include one or more sublayers. However, one or more of the sublayers may have been removed for formation of the half shields 230. Further, the layers may be vertical and/or may be into the plane of the page. For example, the intermediate layer 208 in the recessed view may be formed of different material(s) than in the ABS view. As can be seen in FIGS. 3B-3C, the top of the intermediate layer 208 is between the top of the main pole and the bottom of the main pole in the shield region.

The main pole 210 is shown as having a top wider than the bottom. The main pole 210 thus includes sidewalls 217 and 218 having sidewall angles, α0 and α1 that are greater than or equal to zero. In the embodiment shown, these sidewall angles differ at different distances from the ABS. In some embodiments, α0 (at the ABS) is at least three degrees and not more than fifteen degrees. In some such embodiments, α0 is at least six and not more than nine degrees. The sidewall angle is larger at the ABS than recessed from the ABS. Although α1 is shown as nonzero, in some embodiments, the sidewall angle for the main pole 210 is zero degrees (substantially vertical sidewalls). For example, α1 may be at least zero degrees and not more than five degrees. In some embodiments, α1 is not more than three degrees. Thus, the sidewall angles may decrease to zero as the distance from the ABS increases. However, in other embodiments, other geometries may be used. For example, the top may be the same size as or smaller than the bottom. The sidewall angles may vary in another manner including, but not limited to, remaining substantially constant. FIGS. 3B and 3C depict the main pole 210 as being conformal with the trench in the intermediate layer 208. In some embodiments, however, at least a portion of the main pole 210 is not conformal with the sides of the trench. In some embodiments, the main pole 210 may have leading surface bevel 214 and/or trailing surface bevels 216, as shown in FIG. 3D.

The half shields 230 are shown as including a trailing shield portion. This is denoted by a dotted line in FIG. 3B. In other embodiments, the trailing shield may be omitted. The half side shields 230 are also shown as having a constant thickness in FIG. 3D. Thus, the dashed line corresponding to the bottom of the half shield 230 is perpendicular to the ABS. In other embodiments, the geometry of the half shields 230 may vary. For example, the shields 230 track the trailing edge of the pole such that the shield covers less of the pole further from the ABS. In other embodiments, the half shield thickness may vary. In such embodiments, the bottom of the half shield 230 may be parallel to the leading bevel 214 or the trailing bevel 216 while the top surface is perpendicular to the ABS. Other variations are also possible. However, note that bottom of the half shield 230 is between the top and bottom of the pole 210

The magnetic transducer 200 in the disk drive may be used in shingle recording. Thus, the benefits of shingle recording may be achieved. For example, higher areal density recording may be performed by a head having larger critical dimensions.

FIG. 4 depicts an exemplary embodiment of a method 150 for providing a pole for a magnetic recording transducer having a half shield. For simplicity, some steps may be omitted, interleaved, performed in another order and/or combined. The method 150 is also described in the context of providing a magnetic recording transducer 250 depicted in FIGS. 5A-5C though FIGS. 19A-19D depict an exemplary embodiment of a transducer 250 during fabrication using the method 150. The method 150 may be used to fabricate multiple magnetic recording heads at substantially the same time. The method 150 may also be used to fabricate other magnetic recording transducers. The method 150 is also described in the context of particular layers. A particular layer may include multiple materials and/or multiple sub-layers. The method 150 also may start after formation of other portions of the magnetic recording transducer. For example, the method 150 may start after a read transducer, return pole/shield and/or other structure have been fabricated.

The material(s) for the first sublayer are full-film deposited, via step 152. In some embodiments, step 152 includes full-film depositing silicon oxide. The material(s) for the second sublayer are full-film deposited, via step 154. Step 154 may include depositing aluminum oxide on the silicon oxide layer. FIGS. 5A, 5B and 5C depict side (apex), ABS and plan views of the transducer 250 after step 154 has been performed. Thus, the first nonmagnetic layer 262 has been provided on the underlayer 252. The nonmagnetic layer 264 has been deposited on the first nonmagnetic layer 262. A portion of the first nonmagnetic layer 262 forms at least part of the first sublayer discussed above. A portion of the second nonmagnetic layer 264 forms the second sublayer. Thus, the first nonmagnetic layer 262 may be silicon oxide while the second nonmagnetic layer 264 may be aluminum oxide. Other materials may be used, but the first and second nonmagnetic layer are desired to be removable using different processes for at least some etches. For example, a particular wet etch that would remove the second nonmagnetic layer 264 would not remove the first nonmagnetic layer 252. However, other etches may remove both layers 262 and 264. Both nonmagnetic layers 252 and 254 may be desired to be relatively easily patternable. The total thickness of the nonmagnetic layers 252 and 254 may be at least that desired for the main pole. For example, in some embodiments, the first nonmagnetic layer 262 is at least eight hundred Angstroms thick and not more than one thousand Angstroms thick. The second nonmagnetic layer 264 is at least two thousand Angstroms thick and not more than two thousand four hundred Angstroms thick in some embodiments. Also shown is underlayer 252. The underlayer 252 may include two sublayers. Underlayer 252A may be a NiFe layer used as a leading shield, while underlayer 252B may be a Ru layer. However, in other embodiments, other configurations, including other material(s) may be used. Together, the layers 262 and 264 form layer 260.

A mask that exposes a part of the second nonmagnetic layer 265 is provided, via step 156. Step 156 may include providing a hard mask layer, such as Cr on the second nonmagnetic layer 264. A photoresist mask that covers a portion of the transducer 250 in which the shields are to be formed is provided. FIGS. 6A, 6B and 6C depict side, ABS and plan views of the transducer 250 after these portions of step 156 have been performed. Thus, a hard mask layer 270 and photoresist mask 272 are shown. The hard mask layer may then be etched through as part of step 156. FIGS. 7A, 7B and 7C depict side, ABS and plan views of the transducer 250 after these portions of step 156 have been performed. Thus, hard mask 270′ is shown.

The exposed portions of the first nonmagnetic layer 262 and the second nonmagnetic layer 264 may then be removed, via step 158. Step 158 may be performed using a reactive ion etch (RIE) that is capable of removing both layers 262 and 264. Although some etches (such as a wet etch) may remove only one of the layers 262 or 264, in some embodiments, other etches may remove both. An RIE may be desirable because such an etch may be highly anisotropic, resulting in vertical sidewalls. FIGS. 8A, 8B and 8C depict side, ABS and plan views of the transducer 250 after step 158 has been performed. Thus, the nonmagnetic layers 262′ and 264′ as well as hard mask 270′ remain. The mask 272 has been removed. In the embodiment shown in FIGS. 8A-8C, an RIE has been used in step 158 resulting in vertical sidewalls for the first nonmagnetic layer 262′ and for the second nonmagnetic layer 264′.

A refill step is performed, via step 160. Step 160 includes full film depositing a third nonmagnetic layer for the intermediate layer. The third nonmagnetic layer may be insulating. In some embodiments, the third nonmagnetic layer is the same material as the first nonmagnetic layer 262′. Thus, step 160 may include full film depositing a silicon oxide layer. FIGS. 9A, 9B and 9C depict side, ABS and plan views of the transducer 250 after step 160 has been performed. Thus, the third nonmagnetic layer 266 is shown.

A planarization is then performed, via step 162. The planarization of step 162 may be a chemical mechanical planarization (CMP). Thus, the top of the third nonmagnetic layer 266 is desired to be substantially coplanar with the top of the second nonmagnetic layer 264′. In addition, an ion mill or analogous removal step may be performed to remove the hard mask 270′. FIGS. 10A, 10B and 10C depict side, ABS and plan views of the transducer 250 after step 162 has been performed. Thus, the third nonmagnetic layer 266′ has been planarized. Because nonmagnetic layers 262′ and 266′ may be formed of the same material, they may be considered to form a first sublayer of the intermediate layer. The remaining portion of the second nonmagnetic layer 264′ may form a second sublayer of the intermediate layer 260. Thus, steps 152-162 may be considered to be analogous to step 102.

A mask is provided on the intermediate layer 260, via step 164. The mask includes an aperture that corresponds to a trench to be formed in the intermediate layer 260. Step 164 may be performed using a photoresist line. For example, a first hard mask layer, such as Ta, may be full film deposited. A photoresist mask having a line corresponding to the region of the pole near the ABS is then fabricated on the first hard mask layer. A second hard mask layer, such as Cr, is provided on the first hard mask layer and the photoresist mask. The photoresist is then removed. This may be accomplished by side milling the photoresist mask to remove the second hard mask layer, then performing a lift off. FIGS. 11A, 11B and 11C depict side, ABS and plan views of the transducer 250 after step 164 has been performed. Thus, a first hard mask layer 273 and a second hard mask layer 274 having an aperture 276 therein are shown. The first and second hard mask layers form hard mask 275.

A trench is formed in intermediate layer 260, via step 166. Step 166 may include performing an aluminum oxide RIE (or other RIE(s) appropriate for the layers 262′ and 264′). In some embodiments, multiple RIEs are used to obtain the desired trench profile for various regions of the transducer 250. FIGS. 12A, 12B, 12C and 12D depict side, ABS, recessed and plan views of the transducer 250 after step 166 has been performed. Thus, a trench 280 has been formed in layers 262″, 264″ and 266′. As can be seen in FIGS. 12B and 12C, the sidewall angles of the trench may vary with distance from the ABS. In some embodiments, α2 is greater than α1. For example, α2 may be at least three and not more than fifteen degrees. In some such embodiments, α2 may be at least six and not more than nine degrees. In contrast, α1 may be less than or equal to three degrees. In addition, note that the trench 280 reaches the underlayer 252 in some regions. However, near the ABS, a portion of the layers 262″ and 264″ remain.

Seed layer(s) that are resistant to an etch of the intermediate layer 260 is deposited in the trench, via step 168. In some embodiments, this seed layer may serve as at least part of the gap. The seed layer may include material(s) such as Ru deposited using methods such as chemical vapor deposition. In other embodiments, a magnetic seed layer may be used in lieu of or in addition to a nonmagnetic seed layer. FIGS. 13A, 13B, 13C and 13D depict side, ABS, recessed and plan views of the transducer 250 after step 168 has been performed. Thus, seed layer 282 is shown.

The main pole may then be provided, via step 170. Step 170 includes depositing high saturation magnetization magnetic material(s), for example via electroplating. In some embodiments, the pole provided in step 170 fills the trench 280. However, in other embodiments, the pole may occupy only a portion of the trench. FIGS. 14A, 14B, 14C and 14D depict side, ABS, recessed and plan views of the transducer 250 after a portion of step 170 has been performed. In particular, the pole material(s) 290 have been provided. A planarization, such as a chemical mechanical planarization (CMP) may also be performed. A leading bevel may be naturally formed in the magnetic pole in step 170 due to the shape of the trench 280 and the deposition techniques used. A trailing bevel may also be provided in step 170. For example, a portion of the main pole may be covered by a mask after the planarization. Another portion of the main pole at and near the ABS may be removed, for example via an ion mill. FIGS. 15A, 15B, 15C and 15D depict side, ABS, recessed and plan views of the transducer 250 after step 170 has been completed. Thus, the portion of the main pole materials outside of the trench has been removed, forming main pole 290′. In the embodiment shown, no trailing (top) bevel has been formed. However, in alternate embodiments, such a trailing bevel may be formed before or after formation of the half shields.

A mask used in forming the side shield is provided, via step 172. FIGS. 16A, 16B, 16C and 16D depict side, ABS, recessed and plan views of the transducer 250 after step 172 has been performed. Thus, a mask 296 has been formed.

At least a portion of the second sublayer 264″ outside of the trench 280 and inside of the shield regions is removed, via step 174. Step 174 may include performing an aluminum oxide wet etch. FIGS. 17A, 17B, 17C and 17D depict side, ABS, recessed and plan views of the transducer 250 after step 174 has been performed. Thus, the second sublayer 264″ has been removed, leaving the first sublayer (first nonmagnetic layer 262″ and third nonmagnetic layer 266″).

The half shield(s) may be provided, via step 176. Step 176 includes depositing the material(s) for the half shield. For example, a magnetic material such as NiFe may be electroplated in step 176. In some embodiments, the half shield are part of a wraparound shield. Thus, step 176 may also include providing a wraparound shield. In addition, a write gap layer may also be provided. The magnetic material(s), such as NiFe, for the shield may thus be plated or otherwise deposited. FIGS. 18A, 18B, 18C and 18D depict side, ABS, recessed and plan views of the transducer 250 after step 176 has been performed. Thus, the shield 300 is shown. As can be seen in FIGS. 18B and 18C, the shield 300 includes half shield portions, which terminate on the top of the first layer 262″. Also shown is gap layer 292 that may be nonmagnetic. Thus, the shield 300 extends from above the top of the main pole 290′ to a region between the top and the bottom of the main pole 290′. The proximity of the bottom of the shield 300 to the bottom of the pole 290′ may depend upon design considerations. In some embodiments, a wraparound shield is not desired. In such embodiments, step 176 includes removing a trailing portion of the shield. FIGS. 19A, 19B, 19C and 19D depict side, ABS, recessed and plan views of the transducer 250 after step 170 has been performed in such an embodiment. Thus, the shield 300′ is a half side shield only.

Using the method 150, the transducer 250 including shield 300 or 300′ may be provided. Thus, the benefits of shingle recording may be achieved. For example, higher areal density recording may be performed by a head having larger critical dimensions.