US20080202036A1 - Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing - Google Patents
Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing Download PDFInfo
- Publication number
- US20080202036A1 US20080202036A1 US11/842,823 US84282307A US2008202036A1 US 20080202036 A1 US20080202036 A1 US 20080202036A1 US 84282307 A US84282307 A US 84282307A US 2008202036 A1 US2008202036 A1 US 2008202036A1
- Authority
- US
- United States
- Prior art keywords
- burnishing
- head
- media
- hard disk
- pads
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000004519 manufacturing process Methods 0.000 claims abstract description 14
- 238000000992 sputter etching Methods 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 6
- 239000007888 film coating Substances 0.000 claims description 5
- 238000009501 film coating Methods 0.000 claims description 5
- 229910052710 silicon Inorganic materials 0.000 claims description 5
- 239000010703 silicon Substances 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 238000004544 sputter deposition Methods 0.000 claims description 4
- 239000010409 thin film Substances 0.000 claims description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 2
- 238000005530 etching Methods 0.000 claims 1
- 238000005498 polishing Methods 0.000 abstract description 5
- 230000007547 defect Effects 0.000 abstract description 4
- 238000000227 grinding Methods 0.000 description 9
- 239000000725 suspension Substances 0.000 description 6
- 238000006073 displacement reaction Methods 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 235000012773 waffles Nutrition 0.000 description 5
- 235000012431 wafers Nutrition 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 239000000356 contaminant Substances 0.000 description 3
- 239000011162 core material Substances 0.000 description 3
- 238000000151 deposition Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 208000013201 Stress fracture Diseases 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 238000005461 lubrication Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 241000782128 Albizia adianthifolia Species 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 238000005305 interferometry Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
- B24B37/046—Lapping machines or devices; Accessories designed for working plane surfaces using electric current
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B7/00—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor
- B24B7/20—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground
- B24B7/22—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground for grinding inorganic material, e.g. stone, ceramics, porcelain
- B24B7/228—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground for grinding inorganic material, e.g. stone, ceramics, porcelain for grinding thin, brittle parts, e.g. semiconductors, wafers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
- G11B23/50—Reconditioning of record carriers; Cleaning of record carriers ; Carrying-off electrostatic charges
- G11B23/505—Reconditioning of record carriers; Cleaning of record carriers ; Carrying-off electrostatic charges of disk carriers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/455—Arrangements for functional testing of heads; Measuring arrangements for heads
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/74—Record carriers characterised by the form, e.g. sheet shaped to wrap around a drum
- G11B5/82—Disk carriers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
- G11B5/8404—Processes or apparatus specially adapted for manufacturing record carriers manufacturing base layers
Definitions
- the present invention relates to magnetic hard drive manufacturing. More specifically, the present invention relates to a system for treating (e.g. polishing to remove defects) the surface of a media, such as a magnetic hard disk, while in operation, such as during electrical testing.
- a system for treating e.g. polishing to remove defects
- the surface of a media such as a magnetic hard disk
- One method in the art includes cleaning and burnishing a hard disk following the deposition of thin film layers to remove debris and asperities from the surface.
- parameters such as flying height, disc roughness, and carbon thickness are continually reduced. The successful manufacture of disks capable of meeting these parameters requires improvements to hard disk preparation.
- a burnishing head which replaces the slider of a hard drive suspension such as a head gimbal assembly (HGA), is used to swab the disk surface on-line during dynamic electrical testing (DET) of magnetic heads.
- Such burnishing heads are typically created by diamond-grinding means, which provides a burnishing surface that can result in a dispersal of unwanted head particles as well as a propensity to chip.
- the typical burnishing head design can cause abrupt takeoffs as well as high dynamic pitch angles, being unable to provide a burnishing surface substantially parallel to the media surface (hard disk) as is needed for optimal polishing.
- burnishing head designs are currently utilized in media manufacture (e.g. U.S. Pat. No. 6,267,645; U.S. Pat. No. 6,249,945; and U.S. Pat. No. 5,782,680).
- Some heads have a burnishing ridge providing a burnishing edge that extends across the entire widthwise surface of the head.
- Other head designs have burnishing pads only on various points of the burnishing surface, but have a lengthwise channel between two members.
- burnishing head may result in a lower glide yield, while an overly aggressive glide head may result in scratches and damage to the disk surface, which can lead to disk corrosion.
- the most commonly used burnishing head has a polyangular design, such as rectangular and triangular, with a grinding wheel-cut waffle pattern.
- FIG. 1 provides a burnishing head as is typical in the art.
- the fabrication of such ‘waffle’ burnish heads is accomplished by slotting the head substrate with a diamond grinding wheel (See FIG. 2 ) and taper-lapping.
- utilizing these manufacturing methods results in a high likelihood of micro-fractures in the ceramic and a high level of particulate production.
- the sharp corners 102 are stress concentration areas that are easily broken off and embedded into the disc.
- the burnishing head typically has a taper 104 at the leading 106 and/or trailing 108 edge.
- FIG. 2 provides an illustration of tile grinding steps for creating the ‘waffle head’ pattern as is used in the art.
- Such heads are designed for media manufacture to burnish rough surfaces and are too aggressive to adapt to swab the testing surface of media during DET of magnetic heads. It is therefore desirable to have a system for treating (e.g. polishing to remove defects) the surface of a media such as a magnetic hard disk while on-line without the aforementioned problems.
- FIG. 1 provides a burnishing head as is typical in the art.
- FIG. 2 provides an illustration of the grinding steps for creating the ‘waffle head’ pattern as is used in the art.
- FIG. 3 provides an illustration of a burnishing head under principles of the present invention.
- FIG. 4 provides a cross-section of the burnishing head and the design of an elliptical burnishing pad under principles of the present invention.
- FIG. 5 provides a bottom view and a side cross-section of a burnishing head under principles of the present invention.
- FIG. 6 provides a cross-section of a burnishing head's trailing edge under principles of the present invention.
- FIG. 7 is a perspective view of a parabolic profile for the ABS, such as crown, camber and twist for term descriptive purposes
- FIG. 8 describes the various burnishing head orientations with respect to the media surface for purposes of description.
- FIG. 9 provides a pressure contour of a burnishing head under principles of the present invention.
- FIG. 10 illustrates the process of ion-etching and sputtering for manufacturing a burnishing head under principles of the present invention.
- FIG. 11 shows a cross-section of top and bottom burnishing heads with their associated suspensions in contact with a magnetic hard disk under principles of the present invention.
- FIG. 12 provides a top view of a burnishing head with its associated suspension in contact with a magnetic hard disk under principles of the present invention.
- FIG. 3 provides an illustration of a burnishing head (attached to an HGA) under principles of the present invention.
- the burnishing head (slider) 302 includes a plurality of elliptical pads 304 (typical) that are symmetrically arranged with respect to the burnishing head's axis (of symmetry) 306 .
- the pads 304 are created by ion-etching instead of diamond-grinding to reduce head particulate production and propensity to chip.
- the burnishing head 302 design does not incorporate a taper on the leading edge 308 or the trailing edge 310 . This is to avoid fast (abrupt) takeoffs and high dynamic pitch angles.
- the bottom surface of the burnishing head is coated with silicon & diamond-like carbon (DLC) to optimize head/disk interface (HDI).
- DLC silicon & diamond-like carbon
- HDI head/disk interface
- the burnishing head 302 is loaded at ‘inner diameter’ (ID), and slides slowly from ID to ‘outer diameter’ (OD) as the disk rotates and is then unloaded at OD (See FIG. 11 ). This helps to remove contamination and particle asperity on the testing tracks, which can increase product yield and decrease media consumption.
- the burnishing head 302 is made from a dummy magnetic wafer or conventional ceramic, such as by recycling waste wafers.
- the ion-etching process provides a wide range of burnish head design possibilities. In combination with photolithography, ion-etching can produce a vast array of elliptical geometric shapes. Also, as stated, the elliptical shapes capable of being produced with ion-etching can provide improved performance, reduced chipping, and a lower level of disc damage when compared to typical grinding methods.
- the burnishing head 302 is made from a dummy magnetic wafer (row bar) or a rectangular body of ceramic material (recycled material).
- the pads 304 are carved out by ion milling (IM).
- IM is utilized instead of reactive ion etch (RIE) because of the dangers associated with performing RIE upon alumina layers, e.g. danger of core metal exposure.
- RIE reactive ion etch
- the process of IM is performed on all material at almost the same rate.
- the burnishing head 302 includes no tapering on the leading edge 308 or trailing edge 310 of the air bearing surface (ABS) to avoid fast takeoff or high dynamic pitch.
- ABS air bearing surface
- the placement of the pads 304 in combination with the flat ABS, provides substantially parallel flight over the media to be polished. This ensures light (gentle) media contact to remove surface defects. Further, utilizing the entire ABS for polishing avoids stress concentration. Heavy contact by the burnishing head 302 upon the disk may cause head vibration and could damage the carbon overcoat. Further, during ‘loading and unloading’ (LUL), any dynamic pitch and roll of the burnishing head 302 could cause an edge of the burnishing head 302 to gouge the media.
- LUL loading and unloading
- the burnishing surface of the head 302 is coated with silicon & DLC for lubrication and to enhance durability.
- the silicon/DLC coating is provided after IM to settle loose particles due to re-deposition.
- the burnishing head 302 size is about the same as current sliders (1.235 ⁇ 1.0 ⁇ 0.3 millimeter), and taking advantage of head gimbal assembly (HGA) assembly processes, the burnishing head 302 is mounted on a related suspension 312 so as to be used on-line without fixture limitation during the DET of the project.
- HGA head gimbal assembly
- FIG. 4 provides a cross-section of the burnishing head and the design of an elliptical burnishing pad under principles of the present invention.
- the pads 402 are evenly distributed across the burnishing head's 404 width.
- each pad 402 is oriented such that the burnishing edge 406 faces towards the leading edge of the head 404 to collect contaminants as well as to smooth disk asperities.
- the elliptical (tear drop) pad design 402 causes the burnishing head 404 to be less sensitive to the skew angle of airflow when the head moves during a seek operation (See FIG. 12 ). Further, the pad design 402 minimizes contact stress with the media.
- the head 404 surface has a flat ABS, including a flat crown, camber and twist profile (See FIG. 7 ), to ensure that all burnishing pads 402 are parallel to the surface of the media and are taking part in burnishing.
- FIG. 5 provides a bottom view and a side cross-section of a burnishing head under principles of the present invention.
- the pad 502 configuration includes three evenly distributed leading pads 504 , followed by a second row with four evenly distributed pads 506 , which is followed by a third row with three evenly distributed pads 508 , followed by a fourth row with four evenly distributed pads 510 , and then by two trailing pads 512 .
- the distribution of pads 502 (typical) provides a generally crisscrossed pattern.
- the elliptical pad design causes the area between the pads 502 to be partially evacuated with respect to the surrounding pressure during movement over a media surface. This vacuum is created by the airflow's increased surface velocity (compared to airflow surface velocity). In an embodiment, the generated vacuum provides an evenly distributed suction force lightly holding the burnishing head to the media surface. (See FIG. 9 ). This characteristic aids in absorbing and removing contaminants, as well as maintaining flight stability.
- the angle, ⁇ , of the air grooves (paths) 502 (typical) is more than 25° in order to avoid any burnishing gaps when the head seeks to specific tracks causing large skew angles (See FIG. 12 ).
- the trailing pads 512 do not include a center pad in order to balance the air pressure below the burnishing head and to obtain an ideal flying attitude.
- FIG. 6 provides a cross-section of a burnishing head's 602 trailing edge under principles of the present invention.
- FIG. 7 is a perspective view of a parabolic profile for the ABS, such as crown (parabolic deformation in length), camber (parabolic deformation in width) and twist (parabolic deformation causing equal displacement of diagonal corners) for term descriptive purposes.
- crown is parabolic deformation of the slider in the length direction.
- a positive crown indicates a convex deformation (smaller spacing at slider center), while negative crown indicates a concave deformation (larger spacing at slider center).
- Crown is calculated as follows:
- L is the slider length and R is crown.
- Camber is parabolic deformation of the slider in the width direction. A positive camber indicates a convex deformation (smaller spacing at slider center), while negative camber indicates a concave deformation (larger spacing at slider center). Camber is calculated as follows:
- W is the slider width and A is camber.
- Twist is parabolic deformation of the slider causing equal displacement of diagonal corners.
- a positive twist indicates the inner leading edge and outer trailing edge are recessed (larger spacing), while the outer leading and inner trailing edges are railed (smaller spacing). Twist is defined as follows:
- L is the slider length
- W is the slider width
- T is twist
- FIG. 8 describes the various slider (burnishing head) 802 orientations (with respect to the media surface) for purposes of description.
- FIG. 9 provides a pressure contour of a burnishing head under principles of the present invention.
- the distribution and design of the pads 902 (typical) cause low pressure regions (vacuum) 904 (typical) that provide a balanced suction force for the burnishing head.
- the elliptical pad design 902 causes the area between the pads 904 to be partially evacuated with respect to the surrounding pressure during movement over a media surface. This vacuum is created by the airflow's increased surface velocity (compared to airflow surface velocity). In an embodiment, the generated vacuum provides an evenly distributed suction force lightly holding the burnishing head to the media surface. This characteristic aids in absorbing and removing contaminants, as well as maintaining flight stability.
- FIG. 10 illustrates the process of ion-etching and sputtering for manufacturing a burnishing head under principles of the present invention.
- ion-etching is capable of producing a vast array of complex geometric shapes. Virtually any two-dimensional shape can be ion-etched into the surface of a ceramic slider body, and the etched surface remains virtually stress-free and absent of micro-fractures resulting in reduced head particulate production and propensity to chip.
- the burnishing head is made from a dummy wafer with core material enclosed. The pads are carved out with physical IM, not chemical RIE, preventing the hazards of using RIE on an alumina layer (e.g., core metal exposure).
- a row bar 1002 or a strip of ceramic material is wholly covered with photo-film 1004 .
- a chrome mask 1006 defining the pad configuration, is utilized.
- the film coating 1004 is then exposed to ultra-violet light through the mask 1006 .
- a developer 0.75% Na 2 CO 3 ) removes the unexposed area while the exposed area forms the film pattern attached on the surface of row bar 1002 , which is the photo resistance 1008 to protect the area from ion-etching 1010 .
- the depth of the air grooves (height of the pads) is generally controlled by the amount of time ion-etching 1010 is performed.
- a carbon-thin film overcoating is formed on the entire burnishing surface (including the air groove).
- the surface of the burnishing head is coated with silicon & DLC. As stated, this is done after ion milling (IM) in order to settle loose particles due to re-deposition and for interface lubrication and head durability. In one embodiment, this entire process is done in a relative vacuum.
- IM ion milling
- the individual burnishing heads are separated, cleaned, and inspected (with a device such as an optical interferometry instrument; e.g., a VeccoTM device) to determine the ABS flatness.
- a device such as an optical interferometry instrument; e.g., a VeccoTM device
- FIG. 11 shows a cross-section of top and bottom burnishing heads 1102 with their associated suspensions 1104 in contact with a magnetic hard disk 1110 under principles of the present invention.
- the burnishing heads 1102 are loaded at ‘inner disk’ (ID) 1106 , and slides slowly from ID to ‘outer disk’ (OD) 1108 as the media (disk) 1110 rotates and is then unloaded at OD 1108 . This helps to remove contamination and particle asperity on the testing tracks, which can increase product yield and decrease media consumption.
- FIG. 12 provides a top view of a burnishing head 1202 with its associated suspension 1204 in contact with a magnetic hard disk 1206 under principles of the present invention. Further, the airflow skew angle 1208 is illustrated. The skew is defined by the difference in angular orientation between the slider 1212 and the airflow direction 1210 .
Abstract
A system and method for treating (e.g. polishing to remove defects) the surface of a media, such as a magnetic hard disk, while in operation, such as during dynamic electrical testing is disclosed. Further, a method for manufacturing a head for treating the surface of a media is disclosed.
Description
- The present invention relates to magnetic hard drive manufacturing. More specifically, the present invention relates to a system for treating (e.g. polishing to remove defects) the surface of a media, such as a magnetic hard disk, while in operation, such as during electrical testing.
- In a continuing effort to improve magnetic hard drive performance, efficiency, and reliability, different methods are utilized to improve quality control. One method in the art includes cleaning and burnishing a hard disk following the deposition of thin film layers to remove debris and asperities from the surface. To support ever-increasing areal-density requirements, parameters such as flying height, disc roughness, and carbon thickness are continually reduced. The successful manufacture of disks capable of meeting these parameters requires improvements to hard disk preparation.
- In the art, a burnishing head, which replaces the slider of a hard drive suspension such as a head gimbal assembly (HGA), is used to swab the disk surface on-line during dynamic electrical testing (DET) of magnetic heads. Such burnishing heads are typically created by diamond-grinding means, which provides a burnishing surface that can result in a dispersal of unwanted head particles as well as a propensity to chip. Further, the typical burnishing head design can cause abrupt takeoffs as well as high dynamic pitch angles, being unable to provide a burnishing surface substantially parallel to the media surface (hard disk) as is needed for optimal polishing.
- Several different burnishing head designs are currently utilized in media manufacture (e.g. U.S. Pat. No. 6,267,645; U.S. Pat. No. 6,249,945; and U.S. Pat. No. 5,782,680). Some heads have a burnishing ridge providing a burnishing edge that extends across the entire widthwise surface of the head. Other head designs have burnishing pads only on various points of the burnishing surface, but have a lengthwise channel between two members.
- An ineffective burnishing head may result in a lower glide yield, while an overly aggressive glide head may result in scratches and damage to the disk surface, which can lead to disk corrosion. The most commonly used burnishing head has a polyangular design, such as rectangular and triangular, with a grinding wheel-cut waffle pattern.
-
FIG. 1 provides a burnishing head as is typical in the art. The fabrication of such ‘waffle’ burnish heads is accomplished by slotting the head substrate with a diamond grinding wheel (SeeFIG. 2 ) and taper-lapping. Unfortunately, utilizing these manufacturing methods (to achieve this design) results in a high likelihood of micro-fractures in the ceramic and a high level of particulate production. The sharp corners 102 (typical) of this design are stress concentration areas that are easily broken off and embedded into the disc. Further, as stated, the burnishing head typically has ataper 104 at the leading 106 and/or trailing 108 edge. -
FIG. 2 provides an illustration of tile grinding steps for creating the ‘waffle head’ pattern as is used in the art. First, several parallel grooves are carved out of the burnishing material with a grinding wheel in adiagonal direction 202. Second, several parallel grooves are carved out with the grinding wheel in the other (perpendicular)diagonal direction 204. Third, the material is cut entirely through in a direction perpendicular to the material'slength 206, yielding individual (‘waffle head’) burnishingpads 208. - Such heads are designed for media manufacture to burnish rough surfaces and are too aggressive to adapt to swab the testing surface of media during DET of magnetic heads. It is therefore desirable to have a system for treating (e.g. polishing to remove defects) the surface of a media such as a magnetic hard disk while on-line without the aforementioned problems.
-
FIG. 1 provides a burnishing head as is typical in the art. -
FIG. 2 provides an illustration of the grinding steps for creating the ‘waffle head’ pattern as is used in the art. -
FIG. 3 provides an illustration of a burnishing head under principles of the present invention. -
FIG. 4 provides a cross-section of the burnishing head and the design of an elliptical burnishing pad under principles of the present invention. -
FIG. 5 provides a bottom view and a side cross-section of a burnishing head under principles of the present invention. -
FIG. 6 provides a cross-section of a burnishing head's trailing edge under principles of the present invention. -
FIG. 7 is a perspective view of a parabolic profile for the ABS, such as crown, camber and twist for term descriptive purposes -
FIG. 8 describes the various burnishing head orientations with respect to the media surface for purposes of description. -
FIG. 9 provides a pressure contour of a burnishing head under principles of the present invention. -
FIG. 10 illustrates the process of ion-etching and sputtering for manufacturing a burnishing head under principles of the present invention. -
FIG. 11 shows a cross-section of top and bottom burnishing heads with their associated suspensions in contact with a magnetic hard disk under principles of the present invention. -
FIG. 12 provides a top view of a burnishing head with its associated suspension in contact with a magnetic hard disk under principles of the present invention. -
FIG. 3 provides an illustration of a burnishing head (attached to an HGA) under principles of the present invention. In one embodiment, the burnishing head (slider) 302 includes a plurality of elliptical pads 304 (typical) that are symmetrically arranged with respect to the burnishing head's axis (of symmetry) 306. In an embodiment, thepads 304 are created by ion-etching instead of diamond-grinding to reduce head particulate production and propensity to chip. Further, in an embodiment, the burnishinghead 302 design does not incorporate a taper on the leadingedge 308 or thetrailing edge 310. This is to avoid fast (abrupt) takeoffs and high dynamic pitch angles. As explained below,pad 304 design and distribution, together with the short length and flatness of the air-bearing surface (ABS), enable burnishing head (slider) flight substantially parallel to the media surface. In an embodiment, the bottom surface of the burnishing head is coated with silicon & diamond-like carbon (DLC) to optimize head/disk interface (HDI). As described below inFIG. 11 , working in combination with a DET machine, such as by Guzik Technical Enterprises™, theburnishing head 302 is loaded at ‘inner diameter’ (ID), and slides slowly from ID to ‘outer diameter’ (OD) as the disk rotates and is then unloaded at OD (SeeFIG. 11 ). This helps to remove contamination and particle asperity on the testing tracks, which can increase product yield and decrease media consumption. - In one embodiment of the present invention, the
burnishing head 302 is made from a dummy magnetic wafer or conventional ceramic, such as by recycling waste wafers. The ion-etching process provides a wide range of burnish head design possibilities. In combination with photolithography, ion-etching can produce a vast array of elliptical geometric shapes. Also, as stated, the elliptical shapes capable of being produced with ion-etching can provide improved performance, reduced chipping, and a lower level of disc damage when compared to typical grinding methods. - In one embodiment, the burnishing
head 302 is made from a dummy magnetic wafer (row bar) or a rectangular body of ceramic material (recycled material). Thepads 304 are carved out by ion milling (IM). IM is utilized instead of reactive ion etch (RIE) because of the dangers associated with performing RIE upon alumina layers, e.g. danger of core metal exposure. By contrast, the process of IM is performed on all material at almost the same rate. - As stated, in one embodiment, the
burnishing head 302 includes no tapering on the leadingedge 308 ortrailing edge 310 of the air bearing surface (ABS) to avoid fast takeoff or high dynamic pitch. The placement of thepads 304, in combination with the flat ABS, provides substantially parallel flight over the media to be polished. This ensures light (gentle) media contact to remove surface defects. Further, utilizing the entire ABS for polishing avoids stress concentration. Heavy contact by the burnishinghead 302 upon the disk may cause head vibration and could damage the carbon overcoat. Further, during ‘loading and unloading’ (LUL), any dynamic pitch and roll of the burnishinghead 302 could cause an edge of the burnishinghead 302 to gouge the media. Further, as stated, to improve the HDI in one embodiment, the burnishing surface of thehead 302 is coated with silicon & DLC for lubrication and to enhance durability. The silicon/DLC coating is provided after IM to settle loose particles due to re-deposition. - In an embodiment, the burnishing
head 302 size is about the same as current sliders (1.235×1.0×0.3 millimeter), and taking advantage of head gimbal assembly (HGA) assembly processes, the burnishinghead 302 is mounted on a related suspension 312 so as to be used on-line without fixture limitation during the DET of the project. -
FIG. 4 provides a cross-section of the burnishing head and the design of an elliptical burnishing pad under principles of the present invention. In one embodiment, thepads 402 are evenly distributed across the burnishing head's 404 width. In one embodiment, eachpad 402 is oriented such that the burnishingedge 406 faces towards the leading edge of thehead 404 to collect contaminants as well as to smooth disk asperities. In an embodiment, the elliptical (tear drop)pad design 402 causes the burnishinghead 404 to be less sensitive to the skew angle of airflow when the head moves during a seek operation (SeeFIG. 12 ). Further, thepad design 402 minimizes contact stress with the media. As stated, in an embodiment, thehead 404 surface has a flat ABS, including a flat crown, camber and twist profile (SeeFIG. 7 ), to ensure that all burnishingpads 402 are parallel to the surface of the media and are taking part in burnishing. -
FIG. 5 provides a bottom view and a side cross-section of a burnishing head under principles of the present invention. In one embodiment, thepad 502 configuration includes three evenly distributed leadingpads 504, followed by a second row with four evenly distributedpads 506, which is followed by a third row with three evenly distributedpads 508, followed by a fourth row with four evenly distributedpads 510, and then by two trailingpads 512. The distribution of pads 502 (typical) provides a generally crisscrossed pattern. - In an embodiment, the elliptical pad design causes the area between the
pads 502 to be partially evacuated with respect to the surrounding pressure during movement over a media surface. This vacuum is created by the airflow's increased surface velocity (compared to airflow surface velocity). In an embodiment, the generated vacuum provides an evenly distributed suction force lightly holding the burnishing head to the media surface. (SeeFIG. 9 ). This characteristic aids in absorbing and removing contaminants, as well as maintaining flight stability. - In one embodiment, the angle, θ, of the air grooves (paths) 502 (typical) is more than 25° in order to avoid any burnishing gaps when the head seeks to specific tracks causing large skew angles (See
FIG. 12 ). Also, in one embodiment, the trailingpads 512 do not include a center pad in order to balance the air pressure below the burnishing head and to obtain an ideal flying attitude. -
FIG. 6 provides a cross-section of a burnishing head's 602 trailing edge under principles of the present invention. -
FIG. 7 is a perspective view of a parabolic profile for the ABS, such as crown (parabolic deformation in length), camber (parabolic deformation in width) and twist (parabolic deformation causing equal displacement of diagonal corners) for term descriptive purposes. - To further explain, ‘crown’ is parabolic deformation of the slider in the length direction. A positive crown indicates a convex deformation (smaller spacing at slider center), while negative crown indicates a concave deformation (larger spacing at slider center). Crown is calculated as follows:
-
- Where L is the slider length and R is crown.
- ‘Camber’ is parabolic deformation of the slider in the width direction. A positive camber indicates a convex deformation (smaller spacing at slider center), while negative camber indicates a concave deformation (larger spacing at slider center). Camber is calculated as follows:
-
- where W is the slider width and A is camber.
- ‘Twist’ is parabolic deformation of the slider causing equal displacement of diagonal corners. A positive twist indicates the inner leading edge and outer trailing edge are recessed (larger spacing), while the outer leading and inner trailing edges are railed (smaller spacing). Twist is defined as follows:
-
- where L is the slider length, W is the slider width, and T is twist.
-
FIG. 8 describes the various slider (burnishing head) 802 orientations (with respect to the media surface) for purposes of description. -
FIG. 9 provides a pressure contour of a burnishing head under principles of the present invention. As stated, in one embodiment, the distribution and design of the pads 902 (typical) cause low pressure regions (vacuum) 904 (typical) that provide a balanced suction force for the burnishing head. - In an embodiment, the
elliptical pad design 902 causes the area between thepads 904 to be partially evacuated with respect to the surrounding pressure during movement over a media surface. This vacuum is created by the airflow's increased surface velocity (compared to airflow surface velocity). In an embodiment, the generated vacuum provides an evenly distributed suction force lightly holding the burnishing head to the media surface. This characteristic aids in absorbing and removing contaminants, as well as maintaining flight stability. -
FIG. 10 illustrates the process of ion-etching and sputtering for manufacturing a burnishing head under principles of the present invention. As stated, ion-etching is capable of producing a vast array of complex geometric shapes. Virtually any two-dimensional shape can be ion-etched into the surface of a ceramic slider body, and the etched surface remains virtually stress-free and absent of micro-fractures resulting in reduced head particulate production and propensity to chip. Also in an embodiment, as stated, the burnishing head is made from a dummy wafer with core material enclosed. The pads are carved out with physical IM, not chemical RIE, preventing the hazards of using RIE on an alumina layer (e.g., core metal exposure). - In one embodiment, a
row bar 1002 or a strip of ceramic material is wholly covered with photo-film 1004. In an embodiment, achrome mask 1006, defining the pad configuration, is utilized. Thefilm coating 1004 is then exposed to ultra-violet light through themask 1006. In an embodiment, a developer (0.75% Na2CO3) removes the unexposed area while the exposed area forms the film pattern attached on the surface ofrow bar 1002, which is thephoto resistance 1008 to protect the area from ion-etching 1010. The depth of the air grooves (height of the pads) is generally controlled by the amount of time ion-etching 1010 is performed. - Next, in one embodiment, a carbon-thin film overcoating is formed on the entire burnishing surface (including the air groove). Utilizing sputtering 1012 techniques, the surface of the burnishing head is coated with silicon & DLC. As stated, this is done after ion milling (IM) in order to settle loose particles due to re-deposition and for interface lubrication and head durability. In one embodiment, this entire process is done in a relative vacuum.
- Next, in an embodiment, the individual burnishing heads are separated, cleaned, and inspected (with a device such as an optical interferometry instrument; e.g., a Vecco™ device) to determine the ABS flatness.
-
FIG. 11 shows a cross-section of top and bottom burnishing heads 1102 with their associatedsuspensions 1104 in contact with a magnetichard disk 1110 under principles of the present invention. As described above, the burnishing heads 1102 are loaded at ‘inner disk’ (ID) 1106, and slides slowly from ID to ‘outer disk’ (OD) 1108 as the media (disk) 1110 rotates and is then unloaded atOD 1108. This helps to remove contamination and particle asperity on the testing tracks, which can increase product yield and decrease media consumption. -
FIG. 12 provides a top view of aburnishing head 1202 with its associatedsuspension 1204 in contact with a magnetichard disk 1206 under principles of the present invention. Further, theairflow skew angle 1208 is illustrated. The skew is defined by the difference in angular orientation between theslider 1212 and theairflow direction 1210. - Although several embodiments are specifically illustrated and described herein, it will be appreciated that modifications and variations of the present invention are covered by the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention.
Claims (5)
1-15. (canceled)
16. A method to manufacture a burnishing head comprising:
covering, with a photo-reactive film coating, a row bar;
directing light from a specific range of wavelengths through a mask to said film coating;
removing, with a developer, an unexposed area of said film coating, which leaves an exposed area of said film coating as a photo-resistant surface of said row bar; and
etching said row bar by ion-milling to form a burnishing surface.
17. The method of claim 16 , wherein
said row bar is made with recycled wafer material;
said mask is a chrome mask;
said light is ultra-violet light; and
said developer is 0.75% Na2CO3.
18. The method of claim 16 , further comprising:
applying a carbon-thin film overcoating to said burnishing surface.
19. The method of claim 18 , wherein
said burnishing surface is overcoated with silicon and diamond-like carbon (DLC);
said overcoating is applied via sputtering techniques;
said burnishing surface includes a plurality of raised elliptical pads; and
said method to manufacture a burnishing head is performed in a relative vacuum.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/842,823 US20080202036A1 (en) | 2001-11-20 | 2007-08-21 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CNPCT/CN01/01569 | 2001-11-20 | ||
PCT/CN2001/001569 WO2003046893A1 (en) | 2001-11-20 | 2001-11-20 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
US10/097,682 US7052363B2 (en) | 2001-11-20 | 2002-03-13 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
US11/398,667 US20060223418A1 (en) | 2001-11-20 | 2006-04-06 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
US11/842,823 US20080202036A1 (en) | 2001-11-20 | 2007-08-21 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/398,667 Division US20060223418A1 (en) | 2001-11-20 | 2006-04-06 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
Publications (1)
Publication Number | Publication Date |
---|---|
US20080202036A1 true US20080202036A1 (en) | 2008-08-28 |
Family
ID=4574890
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/097,682 Expired - Lifetime US7052363B2 (en) | 2001-11-20 | 2002-03-13 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
US11/398,667 Abandoned US20060223418A1 (en) | 2001-11-20 | 2006-04-06 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
US11/842,823 Abandoned US20080202036A1 (en) | 2001-11-20 | 2007-08-21 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/097,682 Expired - Lifetime US7052363B2 (en) | 2001-11-20 | 2002-03-13 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
US11/398,667 Abandoned US20060223418A1 (en) | 2001-11-20 | 2006-04-06 | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing |
Country Status (4)
Country | Link |
---|---|
US (3) | US7052363B2 (en) |
JP (1) | JP2003228818A (en) |
CN (2) | CN100379523C (en) |
WO (1) | WO2003046893A1 (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8758092B2 (en) * | 2005-11-16 | 2014-06-24 | Seagate Technology Llc | Sweeper burnish head |
US8137163B2 (en) * | 2009-03-16 | 2012-03-20 | Seagate Technology Llc | Burnish head design with multiple pads on side rail |
US20100330890A1 (en) * | 2009-06-30 | 2010-12-30 | Zine-Eddine Boutaghou | Polishing pad with array of fluidized gimballed abrasive members |
RU2529327C2 (en) * | 2012-12-17 | 2014-09-27 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Волгоградский государственный технический университет" (ВолгГТУ) | Method of combined surface hardening |
US20140295740A1 (en) * | 2013-03-26 | 2014-10-02 | HGST Netherlands B.V. | Ultra fine lapping substrate through use of hard coated material on lapping kinematics |
US20160148631A1 (en) * | 2014-11-26 | 2016-05-26 | Seagate Technology Llc | Slider with micro-patterned coating |
RU2725786C1 (en) * | 2019-12-25 | 2020-07-06 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Кубанский государственный технологический университет" (ФГБОУ ВО "КубГТУ") | Method of increasing strength of a coated part |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5782680A (en) * | 1996-11-13 | 1998-07-21 | Aijohn Establishment | Burnishing head for polishing surfaces of carriers of magnetic media |
US5980369A (en) * | 1997-04-14 | 1999-11-09 | Marburg Technology, Inc. | Level flying burnishing head with circular burnishing pads |
US6249945B1 (en) * | 1998-11-12 | 2001-06-26 | International Business Machines Corporation | Hard disk burnishing head |
US6296552B1 (en) * | 1999-01-29 | 2001-10-02 | Seagate Technology Llc | Burnishing head with fly height control spacer |
US6322431B1 (en) * | 1998-10-13 | 2001-11-27 | Seagate Technology Llc | Burnish head with ion milled aerodynamic pads configured in an elliptical pattern |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5863237A (en) * | 1996-12-04 | 1999-01-26 | Seagate Technology, Inc. | Low speed burnishing of asperities in a disc drive |
US5880899A (en) * | 1997-02-25 | 1999-03-09 | International Business Machines Corporation | Removal of raised irregularities on a data storage disk with controlled abrasion by a magnetoresistive head |
US6273793B1 (en) * | 1998-09-23 | 2001-08-14 | Seagate Technology Llc | Apparatus and method for reducing disc surface asperities to sub-microinch height |
-
2001
- 2001-11-20 WO PCT/CN2001/001569 patent/WO2003046893A1/en active Application Filing
- 2001-11-20 CN CNB2005100545288A patent/CN100379523C/en not_active Expired - Fee Related
- 2001-11-20 CN CN01822115.7A patent/CN1238838C/en not_active Expired - Fee Related
-
2002
- 2002-03-13 US US10/097,682 patent/US7052363B2/en not_active Expired - Lifetime
- 2002-11-18 JP JP2002333605A patent/JP2003228818A/en active Pending
-
2006
- 2006-04-06 US US11/398,667 patent/US20060223418A1/en not_active Abandoned
-
2007
- 2007-08-21 US US11/842,823 patent/US20080202036A1/en not_active Abandoned
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5782680A (en) * | 1996-11-13 | 1998-07-21 | Aijohn Establishment | Burnishing head for polishing surfaces of carriers of magnetic media |
US5980369A (en) * | 1997-04-14 | 1999-11-09 | Marburg Technology, Inc. | Level flying burnishing head with circular burnishing pads |
US6267645B1 (en) * | 1997-04-14 | 2001-07-31 | Marburg Technology, Inc. | Level flying burnishing head |
US6322431B1 (en) * | 1998-10-13 | 2001-11-27 | Seagate Technology Llc | Burnish head with ion milled aerodynamic pads configured in an elliptical pattern |
US6249945B1 (en) * | 1998-11-12 | 2001-06-26 | International Business Machines Corporation | Hard disk burnishing head |
US6296552B1 (en) * | 1999-01-29 | 2001-10-02 | Seagate Technology Llc | Burnishing head with fly height control spacer |
Also Published As
Publication number | Publication date |
---|---|
WO2003046893A1 (en) | 2003-06-05 |
US7052363B2 (en) | 2006-05-30 |
CN100379523C (en) | 2008-04-09 |
JP2003228818A (en) | 2003-08-15 |
CN1486487A (en) | 2004-03-31 |
CN1238838C (en) | 2006-01-25 |
US20030096558A1 (en) | 2003-05-22 |
CN1680076A (en) | 2005-10-12 |
US20060223418A1 (en) | 2006-10-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6246538B1 (en) | Magnetic disk drive with a floating head slider having projections arranged to float at a greater distance from magnetic disk than slider trailing end | |
US20080202036A1 (en) | Method and apparatus for treating the surface of a media, such as a magnetic hard disk, while operating, such as during dynamic electrical testing | |
US5980369A (en) | Level flying burnishing head with circular burnishing pads | |
US6358123B1 (en) | Apparatus and method for reducing disc surface asperities to sub-microinch height | |
US7474507B2 (en) | Storage device having slider with sacrificial extension aligned with channel on opposite surface | |
JP4432199B2 (en) | Method for producing glass substrate for magnetic medium | |
JP2003151233A (en) | Head slider adapted to smooth surface magnetic disk, head slider assembly, magnetic disk device, magnetic disk examining and manufacturing method, and magnetic disk device assembling method | |
US6230380B1 (en) | Slider for burnishing a disc | |
US7245459B2 (en) | Critically exposed lapping of magnetic sensors for target signal output | |
US7244169B2 (en) | In-line contiguous resistive lapping guide for magnetic sensors | |
US20070275270A1 (en) | Information medium | |
US7474503B2 (en) | Thin film magnetic head wafer with identification information | |
US20060286912A1 (en) | Hybrid burnishing head design for improved burnishing of disk media | |
US7281317B2 (en) | Manufacturing method of flying magnetic head slider | |
EP1003157B1 (en) | Hard disk burnishing head | |
US20100196737A1 (en) | Patterned burnish head | |
JP3499461B2 (en) | Processing method of slider | |
JP3764846B2 (en) | Manufacturing method of magnetic head | |
US20040150915A1 (en) | Air bearing surface for a head, and a method of making it | |
US7164557B2 (en) | Apparatus for burnishing small asperities and cleaning loose particles from magnetic recording media | |
JPH10293922A (en) | Magnetic recording medium manufacturing burnish head structure | |
CN1644320A (en) | Method and apparatus to provide a gmr lapping plate texturization using a photo-chemical process | |
JPH04195922A (en) | Magnetic disk manufacturing method | |
JPH0684130A (en) | Floating type magnetic head and its manufacture | |
JP2004220781A (en) | Manufacturing method of head slider |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |