Patents by Inventor Thomas Young Chang

Thomas Young Chang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6521902
    Abstract: The improved method for trimming a magnetic head utilizing a FIB tool includes a step of aligning the FIB tool milling boxes without imaging critical pole tip components and structure. The method includes the creation of an alignment box that is disposed in a known, fixed orientation relative to the FIB tool milling boxes. The FIB tool is aligned by imaging only the alignment box and by moving the alignment box relative to known pole tip structural characteristics that are disposed away from the critical pole tip components. The alignment box is visually aligned on non-sensitive pole tip components in such a manner that the milling boxes will be properly aligned relative to the sensitive pole tip components. FIB tool milling is thereafter performed within the milling boxes which have been accurately aligned without imaging of sensitive pole tip components.
    Type: Grant
    Filed: August 15, 2000
    Date of Patent: February 18, 2003
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Michael Andrew Parker
  • Patent number: 6477008
    Abstract: The present invention is a read/write head for writing information to magnetic media and reading information from magnetic media. It includes a write head element for writing information onto magnetic media, a read head element for reading information from the magnetic media, and an electromagnetic field shield element that is disposed between the write head element and the read head element. The shield functions to shield the read head from electromagnetic field energy created by the write head element. An enhanced second embodiment includes an electrical circuit element that is disposed proximate the read head element that functions to generate an electromagnetic field at the read head element that is generally oppositely directed to the electromagnetic field generated by the write head element to reduce the total electromagnetic field that the read head element is exposed to during a writing operation.
    Type: Grant
    Filed: May 24, 1999
    Date of Patent: November 5, 2002
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Shanlin Duan, Terence Tin-Lok Lam, Wai C. Leung
  • Patent number: 6473276
    Abstract: A single-sided, notched write head is provided for writing narrow erase band servo tracks as well as a double-notched write head, and for writing data tracks better than a double-notched write head. The single-sided, notched write head writes a narrow erase band on the notched side and a wide erase band on the unnotched side. In one embodiment, only one side of the first pole piece layer is notched, and in another embodiment a first side of the first pole piece layer is notched more than a second side. By writing servo tracks only a fraction of the track width of the write head, a wide erase band region is overwritten so that a narrow erase band is on each side of the servo track. Data tracks are written with a narrow erase band on one side and a wide erase band on the other side. The wide erase band on one side of the data track allows more flexibility in spacing the read head from adjacent tracks.
    Type: Grant
    Filed: November 24, 2000
    Date of Patent: October 29, 2002
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Edward Hinpong Lee, Jyh-Shuey Jerry Lo
  • Patent number: 6407891
    Abstract: The present invention is a read/write head for writing information to magnetic media and reading information from magnetic media. It includes a write head for writing information onto magnetic media, a read head for reading information from the magnetic media, and an electrical circuit element that is disposed proximate the read head that functions to generate an electromagnetic field at the read head that is generally oppositely directed to the electromagnetic field generated by the write head. The method for operating the read/write head in a hard disk drive, includes the steps of writing data onto a hard disk, while simultaneously generating an electromagnetic field at the read head that is directed oppositely to the electromagnetic field generated by the write head.
    Type: Grant
    Filed: May 24, 1999
    Date of Patent: June 18, 2002
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Shanlin Duan, Terence Tin-Lok Lam, Wai C. Leung
  • Patent number: 6339872
    Abstract: A single-sided, notched write head is provided for writing narrow erase band servo tracks as well as a double-notched write head, and for writing data tracks better than a double-notched write head. The single-sided, notched write head writes a narrow erase band on the notched side and a wide erase band on the unnotched side. In one embodiment, only one side of the first pole piece layer is notched, and in another embodiment a first side of the first pole piece layer is notched more than a second side. By writing servo tracks only a fraction of the track width of the write head, a wide erase band region is overwritten so that a narrow erase band is on each side of the servo track. Data tracks are written with a narrow erase band on one side and a wide erase band on the other side. The wide erase band on one side of the data track allows more flexibility in spacing the read head from adjacent tracks.
    Type: Grant
    Filed: May 3, 2000
    Date of Patent: January 22, 2002
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Edward Hinpong Lee, Jyh-Shuey Jerry Lo
  • Patent number: 6330128
    Abstract: A magnetic head assembly has an open yoke type write head constructed on top of a read head so that the write head can be constructed with a very narrow track width without restraint by the requirements of the read head. The write head has first and second pole piece portions wherein the second pole piece portion has separate front and back layer portions. A coil layer is wrapped around only the first pole piece portion and the back layer portion so that the front layer portion can be constructed separately to provide a narrow track width. Further, in a preferred embodiment the front layer portion has a reduced thickness and a higher magnetic moment than the thickness and magnetic moment of the first pole piece portion and the back layer portion. Still further, in a preferred embodiment the first pole piece portion and the back layer portion are planar due to planarization of underlying layers.
    Type: Grant
    Filed: April 26, 1999
    Date of Patent: December 11, 2001
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Glen Adam Garfunkel, Edward Hin Pong Lee, Neil Leslie Robertson, Samuel Wonder Yuan
  • Patent number: 6330122
    Abstract: The hard disk testing and certifying device of the present invention includes a spin stand to rotate a disk to be tested. A single read/write head, including both a write head and a read head is mounted upon an armature which movably supports the read/write head. The device includes a computerized control system and signal processing system that provides write signals to the write head and receives and processes read head signals from the read head. In the preferred embodiment the read/write head simultaneously provides write signals to the disk and receives read signals from the disk. Preferably, the read/write head functions continually and the certification testing is conducted utilizing a spiral path. In the preferred read/write head the read head is disposed behind the write head and an electromagnetic field shield is disposed between them to reduce electromagnetic field interference between the write head and the read head during simultaneous operation.
    Type: Grant
    Filed: May 24, 1999
    Date of Patent: December 11, 2001
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Shanlin Duan, Terence Tin-Lok Lam, Wai C. Leung
  • Publication number: 20010037556
    Abstract: A magnetic head assembly has an open yoke type write head constructed on top of a read head so that the write head can be constructed with a very narrow track width without restraint by the requirements of the read head. The write head has first and second pole piece portions wherein the second pole piece portion has separate front and back layer portions. A coil layer is wrapped around only the first pole piece portion and the back layer portion so that the front layer portion can be constructed separately to provide a narrow track width. Further, in a preferred embodiment the front layer portion has a reduced thickness and a higher magnetic moment than the thickness and magnetic moment of the first pole piece portion and the back layer portion. Still further, in a preferred embodiment the first pole piece portion and the back layer portion are planar due to planarization of underlying layers.
    Type: Application
    Filed: July 18, 2001
    Publication date: November 8, 2001
    Inventors: Thomas Young Chang, Glen Adam Garfunkel, Edward Hin Pong Lee, Neil Leslie Robertson, Samuel Wonder Yuan
  • Patent number: 6278591
    Abstract: A method makes an inverted merged MR head with a second pole tip which is self-aligned with a top first pole tip. After forming a bottom first pole tip layer, a top first pole tip is frame plated thereon with a width that defines a track width of the merged MR head. A photoresist layer, which is employed in the frame plating of the top first pole tip, is then soft baked which causes a photoresist opening above the top first pole tip to have sloping side edges which form a recess. An electrically-conductive sacrificial layer, such as copper, is then plated into the recess on top of the top first pole tip and the photoresist is removed. A forming layer, such as alumina, is then deposited and lapped so that the forming layer and the sacrificial layer have top surfaces that are flush with respect to one another. The sacrificial layer is then removed by an etchant that will not attack the materials of the pole tips and the forming layer.
    Type: Grant
    Filed: June 12, 2000
    Date of Patent: August 21, 2001
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Jyh-Shuey Jerry Lo
  • Patent number: 6201670
    Abstract: A single-sided, notched write head is provided for writing narrow erase band servo tracks as well as a double-notched write head, and for writing data tracks better than a double-notched write head. The single-sided, notched write head writes a narrow erase band on the notched side and a wide erase band on the unnotched side. In one embodiment, only one side of the first pole piece layer is notched, and in another embodiment a first side of the first pole piece layer is notched more than a second side. By writing servo tracks only a fraction of the track width of the write head, a wide erase band region is overwritten so that a narrow erase band is on each side of the servo track. Data tracks are written with a narrow erase band on one side and a wide erase band on the other side. The wide erase band on one side of the data track allows more flexibility in spacing the read head from adjacent tracks.
    Type: Grant
    Filed: June 16, 1997
    Date of Patent: March 13, 2001
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Edward Hinpong Lee, Jyh-Shuey Jerry Lo
  • Patent number: 6158107
    Abstract: A method makes an inverted merged MR head with a second pole tip which is self-aligned with a top first pole tip. After forming a bottom first pole tip layer a top first pole tip is frame plated thereon with a width that defines a track width of the merged MR head. A photoresist layer, which is employed in the frame plating of the top first pole tip, is then soft baked which causes a photoresist opening above the top first pole tip to have sloping side edges which form a recess. An electrically-conductive sacrificial layer, such as copper, is then plated into the recess on top of the top first pole tip and the photoresist is removed. A forming layer, such as alumina, is then deposited and lapped so that the forming layer and the sacrificial layer have top surfaces that are flush with respect to one another. The sacrificial layer is then removed by an etchant that will not attack the materials of the pole tips and the forming layer.
    Type: Grant
    Filed: April 2, 1998
    Date of Patent: December 12, 2000
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Jyh-Shuey Jerry Lo
  • Patent number: 6122144
    Abstract: A write head is provided that has an "I" shaped pole tip structure. Flux leakage between bottom corners of a top horizontal component to a bottom horizontal component of the "I" shaped pole tip structure is obviated by rounding or tapering the side edges of the top horizontal component as it recesses into the head from the ABS. The angle taken by each recessed side edge with respect to the ABS edge is less than 90.degree. so that flux concentrations at the corners are minimized and flux leakage from these corners to the bottom horizontal component is substantially eliminated. In another embodiment of the invention the top horizontal component is configured with a necked down portion between front and rear portions for minimizing flux saturation of other pole tip components.
    Type: Grant
    Filed: December 22, 1997
    Date of Patent: September 19, 2000
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, David Eugene Heim, Edward Hinpong Lee
  • Patent number: 6119331
    Abstract: In the manufacture of a combined magnetic head, milling time for notching a first pole piece of the head's write element is reduced by constructing the first pole piece with a notching layer on a first pole piece layer, the notching layer having first and second corners adjacent first and second side walls of the second pole tip. The first pole piece layer has a wide lateral expanse, and the notching layer has a narrow lateral expanse. The width of the notching layer is preferably 0.2 .mu.m to 2.0 .mu.m wider than a target track width of the second pole tip. With this arrangement, the notching layer has first and second side walls that project 0.10 .mu.m to 1.0 .mu.m, laterally, beyond first and second side walls, respectively, of the second pole tip. The thickness of the notching layer is preferably between 0.1 .mu.m to 1.0 .mu.m. Accordingly, full notching of the notching layer can be achieved by milling a small corner in a range of 0.10 .mu.m by 0.10 .mu.m to 1.0 .mu.m by 1.0 .mu.m, as seen in an ABS view.
    Type: Grant
    Filed: July 8, 1997
    Date of Patent: September 19, 2000
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Edward Hinpong Lee, Jhy-Shuey Jerry Lo
  • Patent number: 6069775
    Abstract: A method makes an inverted merged MR head with a second pole tip layer which is self-aligned with a top first pole tip layer. After forming a bottom first pole tip layer, which is relatively thin and relatively wide, a top first pole tip layer is formed thereon with a width that defines the track width of the merged MR head. A second pole tip forming layer is formed on the top first pole tip layer and layers adjacent both sides of the top first pole tip layer. The forming layer and the top first pole tip layer are lapped so that their top surfaces are flush with one another. Ion milling is then implemented to mill the top first pole tip layer at a faster rate than the forming layer causing a recess that is defined by a top surface of the top first pole tip layer and inclined surfaces of the forming layer immediately adjacent thereto.
    Type: Grant
    Filed: December 22, 1997
    Date of Patent: May 30, 2000
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Jyh-Shuey Jerry Lo
  • Patent number: 6054023
    Abstract: A method of making provides an inverted merged MR head wherein frame plating is not required for forming a highly defined submicron track width of a top first pole tip portion. A forming structure is formed on a bottom first pole tip portion with a vertical wall located at a site where one of the edges of the top first pole tip is to be located. The top first pole tip is sputtered or plated on the vertical wall of the forming structure with a thickness that defines the track width of the write head. A mask with a recessed portion may be employed for forming the top first pole tip with a back wall that defines a zero throat height of the head. In a preferred embodiment a forming layer is formed adjacent an opposite edge of the top first pole tip and then the top surfaces of the top first pole tip, the forming layer and the forming structure are lapped until these top surfaces are flush with one another.
    Type: Grant
    Filed: July 26, 1999
    Date of Patent: April 25, 2000
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Jyh-Shuey Jerry Lo
  • Patent number: 6043960
    Abstract: A method of making provides an inverted merged MR head wherein frame plating is not required for forming a highly defined submicron track width of a top first pole tip portion. A forming structure is formed on a bottom first pole tip portion with a vertical wall located at a site where one of the edges of the top first pole tip is to be located. The top first pole tip is sputtered or plated on the vertical wall of the forming structure with a thickness that defines the track width of the write head. A mask with a recessed portion may be employed for forming the top first pole tip with a back wall that defines a zero throat height of the head. In a preferred embodiment a forming layer is formed adjacent an opposite edge of the top first pole tip and then the top surfaces of the top first pole tip, the forming layer and the forming structure are lapped until these top surfaces are flush with one another.
    Type: Grant
    Filed: December 22, 1997
    Date of Patent: March 28, 2000
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Jyh-Shuey Jerry Lo
  • Patent number: 6029339
    Abstract: An inductive write head has a pole tip region between an air bearing surface (ABS) and a flare point, and a yoke region located between the flare point and a back gap. The write head includes first and second pole piece layers, wherein the second pole piece layer has first and second components. The first component extends from an ABS end, which is located at the ABS, to a recessed end which is located in the yoke region. The second component extends from a recessed end, which is spaced from the ABS, to the back gap. The second component interfaces with the first component in a stitched region so that the first component defines a pole tip in the pole tip region and the second component defines a yoke in the yoke region. A first insulation layer extends from a recessed end, which is spaced from the ABS, into the yoke region. The recessed end of the first insulation layer defines a zero throat height. The first component is sandwiched between the first insulation layer and the second component.
    Type: Grant
    Filed: March 4, 1998
    Date of Patent: February 29, 2000
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Mohamad Towfik Krounbi, Edward Hinpong Lee, Douglas Johnson Werner
  • Patent number: 5805391
    Abstract: An inductive write head has a pole tip region between an air bearing surface (ABS) and a flare point, and a yoke region located between the flare point and a back gap. The write head includes first and second pole piece layers, wherein the second pole piece layer has first and second components. The first component extends from an ABS end, which is located at the ABS, to a recessed end which is located in the yoke region. The second component extends from a recessed end, which is spaced from the ABS, to the back gap. The second component interfaces with the first component in a stitched region so that the first component defines a pole tip in the pole tip region and the second component defines a yoke in the yoke region. A first insulation layer extends from a recessed end, which is spaced from the ABS, into the yoke region. The recessed end of the first insulation layer defines a zero throat height. The first component is sandwiched between the first insulation layer and the second component.
    Type: Grant
    Filed: October 28, 1996
    Date of Patent: September 8, 1998
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Mohamad Towfik Krounbi, Edward Hinpong Lee, Douglas Johnson Werner
  • Patent number: 5798897
    Abstract: The present invention employs a ZTH defining insulation layer with a relatively long flat region along with a scheme for eliminating reflective notching from the next insulation layer on top of the ZTH defining insulation layer. This has been accomplished by providing the next insulation layer with a plurality of sloping surfaces which are oriented so that light reflected by the sloping surfaces is directed to areas remote from a pattern of a second pole tip in a photoresist layer which is employed for fabricating the second pole tip. The sloping surfaces terminate at a non-linear front edge which may include a plurality of straight edges extending in predetermined directions. The directions of these straight edges will define the orientations of the sloping surfaces. In one embodiment the straight edges may all be non-parallel and non-perpendicular to the ABS.
    Type: Grant
    Filed: October 21, 1996
    Date of Patent: August 25, 1998
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Edward Hinpong Lee