Method for Fabricating a Magnetic Assembly Having Side Shields

Methods for fabricating a shield structure for a pole tip of a write element for magnetic recording are disclosed. In illustrated embodiments disclosed, a side shield deposition is etched below a front edge surface of the pole tip and one or more depositions are deposited on the etched side shield deposition to form a side shield structure having an extended gap region to enhance performance of the write element. In illustrated embodiments, multiple gap depositions are deposited to form the extended gap region and side shield structure. One or both of the multiple gap depositions are etched to remove outer portions of the deposition prior to depositing the front shield structure.

SUMMARY

The present application discloses methods for fabricating a shield structure for a pole tip of a write element for magnetic recording. In illustrated embodiments disclosed, a side shield deposition is etched below a front edge surface of the pole tip and one or more depositions are deposited on the etched side shield deposition to form a side shield structure having an extended gap region to enhance performance of the write element. In illustrated embodiments, multiple gap depositions are deposited to form the extended gap region and side shield structure. One or both of the multiple gap depositions are etched to remove outer portions of the deposition(s) to form the extended gap region prior to depositing the front shield structure. Other features and benefits that characterize embodiments of the present invention will be apparent upon reading the following detailed description and review of the associated drawings.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present application relates to processing methods for fabricating heads to optimize a gap region between a write pole and shield structure for the pole tip of a write element. The processing methods described optimize the gap region and the shield structure to enhance performance. The disclosed methods utilize wafer fabrication and deposition techniques. As shown inFIG. 1, multiple thin film deposition layers are deposited on a surface100of a wafer or substrate102to form one or more transducer elements104(illustrated schematically inFIG. 1). As shown, the multiple deposition layers include one or more read element layers110and write element layers112. The read and write element layers110,112are illustrated schematically inFIG. 1. Following deposition of the read and write element layers110,112, the wafer102is sliced into a bar chunk116. The bar chunk116includes a plurality of slider bars118(one slider bar118is shown exploded from the chunk116).

The sliced bars118have a leading edge120, a trailing edge122, air bearing surface124and a back surface126. After the bars118are sliced from chunks116, the transducer elements104(read and write elements) deposited on the wafer102are orientated along the air bearing surface(s)124at the trailing edge122of the slider bar118. The slider bar118is sliced to form the heads130. Typically, the bar118is lapped and the air bearing surface(s)124are etched prior to slicing the bar118to form the individual heads130. Illustratively, the wafer102is formed of a ceramic material such as Alumina (Al2O3)—Titanium Carbide (Ti—C) and the read and write elements are fabricated on the ceramic or substrate material of the wafer102to form a slider body132of the head and the one or more deposition layers110,112form the transducer elements104along the trailing edge122of the slider body132.

FIGS. 2A-2Billustrate an embodiment of a write element140for the magnetic head130fabricated from the write deposition layers112. As shown inFIG. 2A, the write element140includes a main pole142having a pole tip144, a top return pole146, a bottom return pole148and a coil150to induce a magnetic flux path through the write pole142to record data on a magnetic recording media152. The main pole142is coupled to a yoke154and is connected to the top return pole146and bottom return pole148through top and bottom back vias156,158. The coil150and poles142,146,148are encapsulated in an insulating structure160. Reference to top and bottom refers to an order of deposition of a bottom pole structure and top pole structure to form the bottom and top return poles146,148. Application of the illustrated embodiments is not limited to the write element140including both a top return pole and a bottom return pole and the write element140can include one or both of the top and bottom return poles146,148.

As schematically illustrated inFIG. 2A, the recording media152rotates in direction as illustrated by arrow164to sequentially record data bits to one or more magnetic layers (not shown) on the media152. In the illustrated embodiment, the write element140is configured to perpendicularly record data to the one or more magnetic layers of the media152. In particular, current is applied to the coil150to induce the magnetic flux path through the main pole142and the return poles146,148to record data in an up/down orientation relative to the media152. As shown inFIG. 2B, the pole tip144is formed along the air bearing surface124of the head130to induce the perpendicular field in the one or more of the magnetic layers of the media152. The direction of the current is varied to vary the direction of the flux path to perpendicularly record data to the media152.

Rotation of the media152for read/write operations provides an air flow along the air bearing surface124of the head130to support the head130above the media152. The air flows along the write element140from a leading edge170of the pole tip144to a trailing edge172of the pole tip144as shown inFIG. 2B. In the illustrated embodiment, the pole tip144is tapered to provide a narrow profile at the leading edge170compared to a width of the pole tip144at the trailing edge172to reduce adjacent track interference and compensate for the skew angle of the media152. As shown inFIGS. 2A-2B, the write element140includes a shield structure for the pole tip144to limit interference and adjacent track erasure for perpendicular magnetic recording. The shield structure includes a front shield174forward or downtrack from the pole tip144connected to the top return pole146. As shown, the front shield174is separated from the pole tip144via an insulating non-magnetic gap region or write gap175. The shield structure also includes side shields176,178extending alongside the pole tip144. In the embodiment illustrated inFIG. 2B, the side shields176,178are separated from the pole tip144by an insulating non-magnetic gap region180along opposed sides of the pole tip144. The side shield structure176,178extends from the gap region180to opposed sides182,184of the head130(shown inFIG. 1).

FIG. 3Aillustrates multiple process steps for fabricating a shield structure for the pole tip144of a write element140. The steps include depositing a side shield deposition on a pole tip structure as illustrated in step200. In step202, the side shield deposition is etched to remove material below a front surface of the pole tip to form a recessed edge surface for the side shield structure176,178. In an illustrated embodiment, the deposition is etched using an ion beam milling process. In step204, one or more gap depositions are deposited on the etched side shield deposition to form the non-magnetic write gap175and extended gap region for the pole tip144. In different embodiments, the one or more gap depositions can comprise the same material or different materials. Thereafter in step206, a front shield deposition is deposited to form the front shield structure174of the write element140.

FIGS. 3B-3Cillustrates different process embodiments utilizing the processing steps described inFIG. 3A. In the illustrated embodiments, the pole tip structure210shown in sequence stop218is fabricated on top of one or more deposition layers110for the read element. In an illustrated embodiment, the pole tip structure210is etched from a deposition stack including a pole tip layer and insulating layer using an ion milling process. The deposition stack is ion milled utilizing a mask to form the pole tip structure210. The ion mill is angled to form a trapezoidal shape pole tip144. A gap layer is deposited along the sides of the pole tip144to form the gap region180of the pole tip structure210. Illustratively, the gap layer is deposited along the upright sides of the pole tip144using a conformal deposition technique such as atom layer deposition (ALD) or other conformal deposition technique. In an alternate embodiment, the pole tip144and pole tip structure210are fabricated utilizing a damascene etching process. In illustrated embodiments, insulating and gap layers are formed of a non-magnetic and electrically insulating material such as Alumina Al2O3and the pole tip144is formed of a magnetically permeable material or ferromagnetic material, such as, but not limited to, iron (Fe), cobalt (Co), and nickel (Ni) and combinations thereof.

As shown in sequence step220, a side shield deposition222is deposited along the gap layer of the pole tip structure210to form the side shields176,178. The deposition222is planarized to form a top surface generally co-planar with a front surface224of the pole tip144at the trailing edge of the pole tip144. The planarization step utilizes a stop layer (not shown) to control the etched depth. In an illustrated embodiment, the stop layer is deposited on the deposition stack prior to etching the deposition stack to form the pole tip structure210. The deposition222is deposited on the pole tip structure210using a conductive seed layer to electro-plate the deposition222to the pole tip structure210. The deposition222is planarized utilizing a chemical mechanical polishing (CMP) processing step.

In sequence step230shown, a stop layer232is deposited on the top surface of the deposition222. In an illustrated embodiment, the stop layer232is a CMP stop layer material to control removal of material during a planarization step. As progressively illustrated in sequence step234, mask236is patterned to etch the side shield deposition222below the front surface224of the pole tip144to form a recessed trailing edge surface237uptrack from the trailing edge of the pole tip144as illustrated in step238. In an illustrated embodiment, mask236is patterned using a photolithography and etching process, such as an inductively coupled plasma (ICP) etching process.

The side shield deposition222is etched using an ion beam etch to etch through the stop layer232and a trailing portion of the side shield deposition222as shown. As shown, an entire width of the side shield deposition is etched between opposed sides182,184of the head or slider body132. In the illustrated embodiment, the side shield deposition222is etched to a depth proximate to mid-length or mid-height of the pole tip144. In another illustrated embodiment, the etched depth is about a third of the pole tip144height between the leading and trailing edges170,172of the pole tip144so that the etched depth is at least a third of the pole tip144height. In another embodiment, the etch depth is about three quarters of the pole tip144height. In sequence step240, the mask236is removed and in sequence step242, a first gap deposition244is deposited on the etched side shield deposition222as shown.

In sequence step246, the first gap deposition244is planarized to remove a portion of the deposition244over the front surface224of the pole tip144. In an illustrated embodiment, the deposition244is etched or planarized using CMP and the stop layer232prevents over-polishing. In particular, the stop layer232is used to control the depth of material removed during the planarization process in step246to control the removal depth of the gap deposition244. As shown, the stop layer232over the pole region is protected by the mask236during the etching step238. The stop layer232is removed by an etching process following the CMP in step246. A second gap deposition250is deposited over the first gap deposition244and the pole gap region180and planarized to form the write gap175forward of the pole tip144in step252. In sequence step254, a front shield deposition256is deposited to form the front shield structure174connected to the return pole144of the write element140as illustrated inFIG. 2A. The process sequence disclosed provides steps for fabrication of a side shield structure having a truncated trailing edge surface237spaced uptrack from the trailing edge172or front surface224of the pole tip144and extended gap region between the side shield structure176,178and the front shield structure174. The truncated side shield structure reduces the flux leakage proximate to the trailing edge172of the pole tip144to enhance write field gradient and field strength.

The side shield and front shield depositions222,256are formed of the same or similar ferromagnetic materials as the pole tip144. For example in illustrated embodiments, deposition material for the side and front shields include but is not limited to iron cobalt (CoxFey), iron nickel (FeyNix) or cobalt iron nickel (CoxFeyNiz). In one embodiment, both the pole tip144and side and front shields174,176,178are formed of a high magnetic moment alloy. The gap depositions244,250are a non-magnetic insulating material such as Alumina or other ceramic or non-magnetic insulating material.

FIG. 3Cillustrates a process sequence similarly incorporating the process steps disclosed inFIG. 3Awhere like numbers are used to identify like parts in the previous FIGS. In the illustrated embodiment shown inFIG. 3C, the process sequence is used to fabricate a box shield structure. The pole tip structure210for the box shield structure is formed from a deposition stack including a bottom shield layer260to form a leading shield structure, as well as the insulating layer and pole tip layer. The bottom shield layer260is formed of a ferromagnetic material as previously described for the side shield and front shield depositions222,256. The gap layer is deposited on the etched deposition stack to form the pole tip structure210for the box shield structure including the gap region180as shown in sequence step262. In sequence step266, the side shield deposition222is deposited on the pole tip structure210and planarized as previously described. In sequence step270, the stop layer232is deposited on top of the pole tip144and the planarized side shield deposition222.

In sequence step272, mask236is patterned over stop layer232along a pole tip region as shown. Thereafter in sequence step276, the side shield deposition222is etched below the front surface224of the pole tip144so that a top surface of the side shield deposition222is recessed below the trailing edge172of the pole tip144to form the trailing edge surface237of the side shield structure uptrack from the trailing edge172of the pole tip144. As previously described in step278, the mask236is removed and in step280the first gap deposition244is deposited on the etched surfaces. The first gap deposition244is planarized in step282to remove material above the front surface224of the pole tip144using a CMP process. As previously described, the stop layer232is used to control a planarization depth of the first gap deposition244and is etched following CMP as shown in step282. The second gap deposition250is deposited over the first gap deposition244and the pole tip region in sequence step284and planarized. In sequence step286, the front shield deposition256is deposited over the second gap deposition250to form the front shield structure of the write element140separated from the pole tip144via write gap175.

FIG. 4Aillustrates another embodiment for fabricating the shield structure for the pole tip144of a write element140. As illustrated inFIG. 4A, in step300, the side shield deposition222is deposited to form the side shield structure on the pole tip structure210. In step302, the side shield deposition222is etched to form an edge surface recessed below a front surface224of the pole tip144. In step304, a bottom or first gap deposition244is deposited on the etched side shield deposition222. Thereafter in step306, a top or second gap deposition250is deposited over the first gap deposition244forward of the front edge of the pole tip. In step308, the first and second gap depositions244,250are etched to form the write gap175and the extended gap region. Thereafter in step310, the front shield deposition256is deposited over the etched gap depositions244,250to form a top side shield portion and the front shield structure174of the write element140.

FIGS. 4B-4Cillustrate embodiments utilizing the process steps disclosed inFIG. 4Awhere like numbers are used to identify like parts. In the embodiment illustrated inFIG. 4B, a deposition stack is etched using a mask and the gap layer is deposited to form the pole tip structure210shown in sequence step320as previously described. In sequence step322, the side shield deposition222is deposited on the pole tip structure210and planarized. As previously described, the side shield deposition222is electro-plated to a seed layer (not shown) deposited on the pole tip structure210. In sequence step324, stop layer232is deposited and mask236is patterned over the stop layer232to etch the side shield deposition222to form the recessed edge surface237uptrack from the front surface224of the pole tip144as illustrated in sequence step326. In step328, the first gap deposition244is deposited. The first gap deposition244is planarized utilizing the stop layer232to control the etched depth as illustrated in sequence step330as previously described.

In step332, the second gap deposition250is deposited over the first gap deposition244and the pole tip region. In sequence step334, mask340is patterned to etch the first and second gap depositions244,250to form the expanded gap region along a trailing edge portion of the pole tip144. In an illustrated embodiment, the mask340is a patterned resist and the first and second gap depositions244,250are ion milled or etched to remove outer portions of the depositions244,250spaced from the pole tip and gap region180. In sequence step342, the mask340is removed and in sequence step344, the front shield deposition256is deposited over the etched first and second gap depositions244,250to form top portions of the side shield structure and the front shield structure174. Illustratively, the front shield deposition256is electro-plated to the side shield structure and gap deposition250via a conductive seed layer (not shown).

FIG. 4Cillustrates another embodiment for a box shield structure utilizing the process steps ofFIG. 4A, where like numbers are used to refer to like parts in the previous FIGS. As previously described inFIG. 3C, the deposition stack for the box shield structure includes the bottom shield layer260as shown in sequence step350ofFIG. 4Cto form the leading shield structure. In sequence step352the side shield deposition222is deposited on the pole tip structure210including the bottom shield layer260to form the box shield structure. As previously described, the side shield deposition222is deposited on a conductive seed layer on the pole tip structure210. Similar toFIG. 4B, in step354, stop layer232is deposited on the side shield deposition222and mask236is patterned on the stop layer232to etch the side shield deposition222to form the recessed edge surface237uptrack from the trailing edge172of the pole tip as illustrated in sequence step356.

In step358, the first gap deposition244is deposited and planarized as shown in step360utilizing the stop layer232. In step362, the second gap deposition250is deposited. In sequence step364, mask340is patterned to etch the first and second gap depositions244,250as shown in sequence step368. In sequence step370, the front shield deposition256is deposited on the etched side shield deposition222to form a top portion of the side shield structure and the front shield structure174as previously described.

FIG. 5Aillustrates another embodiment for fabricating the shield structure for the pole tip144of the write element140. As illustrated inFIG. 5A, in step400the side shield deposition222is deposited on the pole tip structure210as previously described. In step402, the side shield deposition222is etched to form the trailing edge surface237of the side shield structure recessed below the front surface224of the pole tip144. In step404, a bottom or first gap deposition244is deposited on the etched side shield deposition222. In step406, portions of the first gap deposition244are etched. In step408a top or second gap deposition250is deposited. In step410the front shield deposition256is deposited over the top or second gap deposition250to form the front shield structure174of the write element140separated from the pole tip144via write gap175formed by the second gap deposition250.

FIG. 5Billustrates embodiments utilizing the process steps described inFIG. 5A. As previously described, the side shield deposition222is deposited on the pole tip structure210formed by the etched deposition stack and gap layer. In sequence step450, the side shield deposition222is etched using the patterned mask236to form a trailing edge surface237recessed below the front surface224of the pole tip144as previously described in other embodiments. In sequence steps452,454, the first gap deposition244is deposited and planarized utilizing the stop layer232as previously described. In sequence step456, the first gap deposition244is etched using mask340to remove outer portions of the deposition244to form the extended gap region. The mask340is removed in sequence step458and in step460, the second gap deposition250is deposited over the first gap deposition244and outer portions of the side shield deposition222. In sequence step462, the front shield deposition256is deposited to form the front shield structure174as previously described.

FIG. 5Cillustrates a box shield embodiment utilizing the process steps described inFIG. 5A. InFIG. 5C, the side shield deposition222is deposited on the pole tip structure210etched from a deposition stack including the bottom shield layer260as previously described with respect toFIG. 3C. Similar toFIG. 5B, in sequence step470, the side shield deposition222is etched using the patterned mask236to form the trailing edge surface237recessed below the front surface224of the pole tip144as previously described in other embodiments. In sequence steps472,474, the first gap deposition244is deposited and planarized. In sequence step476, the first gap deposition244is etched using mask340. The mask340is removed in sequence step478and in sequence step480, the second gap deposition250is deposited. Thereafter in step482, the front shield deposition256is deposited to form the front shield structure174, write gap175and extended gap region as previously described.

FIG. 6Aillustrates another embodiment for fabricating the shield structure for the pole tip144separated from the pole tip144via a gap region having a graded magnetic structure formed of a graded magnetic moment material.FIG. 6Aillustrates fabrication steps for fabricating the graded magnetic structure for the gap region. As shown in step484, the side shield deposition222is etched below the front surface224of the pole tip144as previously described with respect to the embodiments disclosed inFIGS. 3B-3C,FIGS. 4B-4CandFIGS. 5B-5C. In step486, gap deposition244is deposited on the etched side shield deposition222. Deposition of the gap deposition244includes deposition of multiple different layers having different material compositions to provide the graded magnetic moment gap structure providing a differential shielding effect along the trailing portion of the pole tip144. Thereafter in step488, the front shield deposition256is deposited to form the front shield structure174for the pole tip144as previously described.

In illustrative embodiments, the layers of the graded gap structure are formed of ferromagnetic alloy materials such as cobalt iron CoxFey, iron nickel FeyNixcobalt iron nickel CoxFeyNizand the percentages of x, y, and/or z of one or more of the alloy elements is varied along the length or width of the extended gap region or write gap175to provide the graded magnetic moment material having a graded saturation magnetization Ms to limit flux leakage to the side shield structure176,178proximate to the trailing edge172of the pole tip144.

FIG. 6Billustrates an embodiment utilizing the process steps described inFIG. 6A. As previously described, the side shield deposition222is etched to a height recessed below the front surface224of the pole tip144. As shown, multiple gap layers492are sequentially deposited to form the gap deposition244along the etched side shield deposition222utilizing for example, a chemical vapor deposition process. The multiple gap layers492have different material compositions to provide the graded magnetic moment structure along the trailing portion of the pole tip144. The different material compositions have different magnetic permeability or different magnetic moments. For example, the layers492are arranged so that the permeability or magnetic moment decreases in the downtrack direction to reduce flux leakage proximate to the trailing edge172of the pole tip144.

InFIG. 6C, multiple gap layers500,502are orientated lengthwise and are spaced in a cross-track direction. The multiple gap layers500,502of the extended gap are formed via sequential deposition and etching steps510,512,514,516as progressively illustrated inFIG. 6C. In particular, in step510, layer500is deposited and etched via mask520in step512. Layer502is deposited and planarized in step514, and etched in step516via mask522as illustrated in sequence step524. The process of depositing the gap layer and etching the gap layer is repeated based upon design criteria of the graded structure and size of the extended gap region. Each of the multiple layer gap depositions or structures can be utilized to form the gap region for the previous embodiments illustrated inFIGS. 3B-3C,4B-4C and5B-5C, however application is not limited to the embodiments shown inFIGS. 3B-3C,4B-4C and5B-5C.