Patents by Inventor Po-Kang Wang

Po-Kang Wang 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).

  • Publication number: 20030202295
    Abstract: As track density requirements for disk drives have grown more aggressive, GMR devices have been pushed to narrower track widths to match the track pitch of the drive width. Narrower track widths degrade stability, cause amplitude loss, due to the field originating from the hard bias structure, and side reading. This problem has been overcome by adding an additional layer of soft magnetic material above the hard bias layers. The added layer provides flux closure to the hard bias layers thereby preventing flux leakage into the gap region. A non-magnetic layer must be included to prevent exchange coupling to the hard bias layers. In at least one embodiment the conductive leads are used to accomplish this. A process for manufacturing the device is also described.
    Type: Application
    Filed: April 30, 2002
    Publication date: October 30, 2003
    Applicant: Headway Technologies, Inc.
    Inventors: Po Kang Wang, Moris Dovek, Jibin Geng, Tai Min
  • Publication number: 20030189801
    Abstract: In magnetic read heads based on bottom spin valves the preferred structure is for the longitudinal bias layer to be in direct contact with the free layer. Such a structure is very difficult to manufacture. The present invention overcomes this problem by introducing an extra layer between the bias electrodes and the free layer. This layer protects the free layer during processing but is thin enough to not interrupt exchange between the bias electrodes and the free layer. In one embodiment this is a layer of copper about 5 Å thick and parallel exchange is operative. In other embodiments ruthenium is used to provide antiparallel exchange between the bias electrode and the free layer. A process for manufacturing the structure is also described.
    Type: Application
    Filed: April 5, 2002
    Publication date: October 9, 2003
    Applicant: Headway Technologies, Inc.
    Inventors: Moris Dovek, Po-Kang Wang, Chen-Jung Chien, Chyu-Jiuh Torng, Yun-Fei Li
  • Patent number: 6608737
    Abstract: A giant magneto-resistive head is provided which includes a novel high data-rate stitched pole inductive magnetic write head. The write head incorporates a non-magnetic spacer layer and a magnetic pole yoke that is recessed from the magnetic pole tip. The spacer layer shortens the throat height of the write head, reduces its saturation write current, and improves its overwrite and side erasure performance.
    Type: Grant
    Filed: October 8, 2002
    Date of Patent: August 19, 2003
    Assignee: Headway Technologies, Inc.
    Inventors: Cherng-Chyi Han, Mao-Min Chen, Po-Kang Wang, Moris Musa Dovek, Gene Michael Sandler, Jen-Wei C. Koo
  • Patent number: 6606782
    Abstract: To form a spin valve device, start by forming a gap layer. Form a buffer layer with a layer of refractory material on the buffer layer. Form patterned underlayers including a magnetic material for providing trackwidth and longitudinal bias on the buffer layer comprising either a lower antiferromagnetic layer stacked with a ferromagnetic layer or a Cr layer stacked with a permanent magnetic layer. Form an inwardly tapered depression in the patterned underlayers down to the buffer layer by either ion milling through a mask or a stencil lift off technique. Form layers covering the patterned underlayers that cover the inwardly tapered depression. Form free, pinned, spacer and antiferromagnetic layers. Form conductors either on a surface of the antiferromagnetic layer aside from the depression or between the buffer layer and the patterned underlayers.
    Type: Grant
    Filed: March 22, 2002
    Date of Patent: August 19, 2003
    Assignee: Headway Technologies, Inc.
    Inventors: Tai Min, Po-Kang Wang, Moris Musa Dovek
  • Patent number: 6556377
    Abstract: A structure and a method for a stitched write head having a sunken share pole. The method includes forming a bottom coil dielectric layer over the first half shared pole. Coils are formed over the bottom coil dielectric layer. Next, second half shared poles (P1) are formed over the first half shared pole (S2). We form a top coil dielectric layer over the structure. In a key step, we chemical-mechanical polish the top coil dielectric layer. A write gap layer (WG) is formed over the front second half shared pole and the top coil dielectric layer over the coils. An upper pole (P3) and hard mask are formed over the write gap layer. We etch the write gap layer and the second half shared pole (P1) using the upper pole as an etch mask to remove a portion of the second half shared pole (P1) adjacent to the write gap layer thereby forming a partially trimmed pole.
    Type: Grant
    Filed: September 6, 2002
    Date of Patent: April 29, 2003
    Assignee: Headway Technologies, Inc.
    Inventors: Mao-Min Chen, Po-Kang Wang, Cherng-Chyi Han
  • Patent number: 6524491
    Abstract: A method of manufacturing a magnetic recording head includes the following steps. Form a low magnetic moment, first magnetic shield layer over a substrate. Form a read gap layer with a magnetoresistive head over the first shield layer. Form a seed layer over the read gap layer covered with a frame mask with a width “F”. Form a PLM second shield layer over the seed layer and planarize the shield layer. Form a non-magnetic copper or dielectric spacer layer over the PLM second shield layer. Form a first HMM, lower pole layer over the non-magnetic spacer layer. Cover the first HMM, lower pole layer with a write gap layer. Form an write head mask composed of two parallel rows of resist with an outer width “W” over the seed layer. Between the two rows of resist of the write head mask is a trench having a width “N”. Then form an HMM, upper pole layer over the write gap layer aside from the write head mask.
    Type: Grant
    Filed: April 26, 1999
    Date of Patent: February 25, 2003
    Assignee: Headway Technologies, Inc.
    Inventors: Chun Liu, Cherng-Chyi Han, Kochan Ju, Po-Kang Wang, Jei-Wei Chang
  • Publication number: 20030030943
    Abstract: A high data-rate stitched pole inductive magnetic write head incorporating a non-magnetic spacer layer and a magnetic pole yoke that is recessed from the magnetic pole tip. The spacer layer shortens throat height, reduces saturation write current, and improves overwrite and side erasure performance.
    Type: Application
    Filed: October 8, 2002
    Publication date: February 13, 2003
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Cherng-Chyi Han, Mao-Min Chen, Po-Kang Wang, Moris Musa Dovek, Gene Michael Sandler, Jen-Wei C. Koo
  • Publication number: 20030026047
    Abstract: The possibility of shorting between a spin valve and its underlying magnetic shield layer can be largely eliminated by choosing the bottom spin valve structure. However, doing so causes the hard longitudinal bias that is standard for all such devices to degrade. The present invention overcomes this problem by inserting a thin NiCr, Ni, Fe, or Cr layer between the antiferromagnetic layer and the longitudinal bias layers. This provides a smoother surface for the bias layers to be deposited onto, thereby removing structural distortions to the longitudinal bias layer that would otherwise be present. A process for manufacturing the structure is also described.
    Type: Application
    Filed: July 30, 2001
    Publication date: February 6, 2003
    Applicant: Headway Technologies, Inc.
    Inventors: Chen-Jung Chien, Chyu-Jiuh Torng, Cherng-Chyi Han, Moris Dovek, Po-Kang Wang, Mao-Min Chen
  • Publication number: 20030002212
    Abstract: A structure and a method for a stitched write head having a sunken share pole. The method includes forming a bottom coil dielectric layer over the first half shared pole. Coils are formed over the bottom coil dielectric layer. Next, second half shared poles (P1) are formed over the first half shared pole (S2). We form a top coil dielectric layer over the structure. In a key step, we chemical-mechanical polish the top coil dielectric layer. A write gap layer (WG) is formed over the front second half shared pole and the top coil dielectric layer over the coils. An upper pole (P3) and hard mask are formed over the write gap layer. We etch the write gap layer and the second half shared pole (P1) using the upper pole as an etch mask to remove a portion of the second half shared pole (P1) adjacent to the write gap layer thereby forming a partially trimmed pole.
    Type: Application
    Filed: September 6, 2002
    Publication date: January 2, 2003
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Mao-Min Chen, Po-Kang Wang, Cherng-Chyi Han
  • Publication number: 20020159200
    Abstract: A merged read/write magnetic recording head comprises a low magnetic moment first magnetic shield layer over a substrate. A read gap layer with a magnetoresistive head is formed over the first shield layer. A shared pole comprises a low magnetic moment second magnetic shield layer plated on a sputtered seed PLM layer over the read gap layer, a non-magnetic layer plated over the PLM layer and a HMM lower pole layer plated over the second magnetic shield layer. A write gap layer is formed over the first high magnetic moment pole layer of the shared pole. An upper pole comprises a high magnetic moment pole layer over the write gap layer.
    Type: Application
    Filed: April 24, 2002
    Publication date: October 31, 2002
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Kochan Ju, Cherng-Chyi Hau, Po-Kang Wang, Mao-Min Chen, Chun Liu, Jei Wei Chang
  • Patent number: 6469875
    Abstract: A structure and a method for a stitched write head having a sunken share pole. The method includes forming a bottom coil dielectric layer over the first half shared pole. Coils are formed over the bottom coil dielectric layer. Next, second half shared poles (P1) are formed over the first half shared pole (S2). We form a top coil dielectric layer over the structure. In a key step, we chemical-mechanical polish the top coil dielectric layer. A write gap layer (WG) is formed over the front second half shared pole and the top coil dielectric layer over the coils. An upper pole (P3) and hard mask are formed over the write gap layer. We etch the write gap layer and the second half shared pole (P1) using the upper pole as an etch mask to remove a portion of the second half shared pole (P1) adjacent to the write gap layer thereby forming a partially trimmed pole.
    Type: Grant
    Filed: March 15, 2000
    Date of Patent: October 22, 2002
    Assignee: Headway Technologies, Inc.
    Inventors: Mao-Min Chen, Po-Kang Wang, Cherng-Chyi Han
  • Patent number: 6469874
    Abstract: A high data-rate stitched pole inductive magnetic write head incorporating a non-magnetic spacer layer and a magnetic pole yoke that is recessed from the magnetic pole tip. Said spacer layer is deposited as part of a self-aligned, patterned photoresist process, wherein the spacer layer is deposited first and the P2 portion of the upper pole assembly is then plated over it to form the pole tip configuration. Increasing the thickness of the spacer layer, while keeping it within a specified tolerance range, allows the upper stitched P3 portion of the pole piece to be recessed relative to the tip of P2. The spacer layer shortens throat height, reduces saturation write current, and improves overwrite and side erasure performance.
    Type: Grant
    Filed: March 13, 2000
    Date of Patent: October 22, 2002
    Assignee: Headway Technologies, Inc.
    Inventors: Cherng-Chyi Han, Mao-Min Chen, Po-Kang Wang, Moris Musa Dovek, Gene Michael Sandler, Jeu-Wei C. Koo
  • Publication number: 20020126429
    Abstract: A spin valve device comprises a free layer, a spacer layer, a pinned layer, an antiferromagnetic layer, and a patterned underlayer that includes a magnetic material for providing trackwidth and longitudinal bias. The patterned underlayer can comprise a buffer layer, an antiferromagnetic layer and a ferromagnetic layer. Alternatively, the patterned underlayer can comprises a buffer layer, a chromium layer and a hard biasing, permanent magnetic layer which provides trackwidth and longitudinal bias. A lower conductor can be located on the underlayer.
    Type: Application
    Filed: March 22, 2002
    Publication date: September 12, 2002
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Tai Min, Po-Kang Wang, Moris Musa Dovek
  • Patent number: 6449131
    Abstract: A dual stripe magnetoresistive (DSMR) sensor element, and a method for fabricating the dual stripe magnetoresistive (DSMR) sensor element. When fabricating the dual stripe magnetoresistive (DSMR) sensor element while employing the method, there are employed two pair of patterned magnetic biasing layers formed of a single magnetic biasing material. The two pair of patterned magnetic biasing layers bias a pair of patterned magnetoresistive (MR) layers in a pair of opposite canted directions.
    Type: Grant
    Filed: March 28, 2001
    Date of Patent: September 10, 2002
    Assignee: Headway Technologies, Inc.
    Inventors: Yimin Guo, Kochan Ju, Po-Kang Wang, Cherng-Chyi Han, Hui-Chuan Wang
  • Publication number: 20020094374
    Abstract: A method for forming a magnetoresistive (MR) layer first employs a substrate over which is formed a magnetoresistive (MR) layer formed of a magnetoresistive (MR) material. There is then ion implanted selectively, while employing an ion implant method, the magnetoresistive (MR) layer to form: (1) an ion implanted portion of the magnetoresistive (MR) layer formed of an ion implanted magnetoresistive (MR) material; and (2) an adjoining non ion implanted portion of the magnetoresistive (MR) layer formed of the magnetoresistive (MR) material, where the ion implanted magnetoresistive (MR) material is a non magnetoresistive (MR) material. The method may be employed for forming within magnetoresistive (MR) sensor elements magnetoresistive (MR) layers with enhanced dimensional uniformity, and in particular enhanced overlay dimensional uniformity.
    Type: Application
    Filed: March 18, 2002
    Publication date: July 18, 2002
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Cherng-Chyi Han, Rong-Fu Xiao, Mao-Min Chen, Po-Kang Wang
  • Patent number: 6393692
    Abstract: A merged read/write magnetic recording head comprises a low magnetic moment first magnetic shield layer over a substrate. A read gap layer with a magnetoresistive head is formed over the first shield layer. A shared pole comprises a low magnetic moment second magnetic shield layer plated on a sputtered seed PLM layer over the read gap layer, a non-magnetic layer plated over the PLM layer and a HMM lower pole layer plated over the second magnetic shield layer. A write gap layer is formed over the first high magnetic moment pole layer of the shared pole. An upper pole comprises a high magnetic moment pole layer over the write gap layer.
    Type: Grant
    Filed: April 1, 1999
    Date of Patent: May 28, 2002
    Assignee: Headway Technologies, Inc.
    Inventors: Kochan Ju, Cherng-Chyi Han, Po-Kang Wang, Mao-Min Chen, Chun Liu, Jei-Wei Chang
  • Patent number: 6385017
    Abstract: A spin valve device comprises a free layer, a spacer layer, a pinned layer, an antiferromagnetic layer, and a patterned underlayer that includes a magnetic material for providing trackwidth and longitudinal bias. The patterned underlayer can comprise a buffer layer, an antiferromagnetic layer and a ferromagnetic layer. Alternatively, the patterned underlayer can comprises a buffer layer, a chromium layer and a hard biasing, permanent magnetic layer which provides trackwidth and longitudinal bias. A lower conductor can be located on the underlayer.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: May 7, 2002
    Assignee: Headway Technologies, Inc.
    Inventors: Tai Min, Po-Kang Wang, Moris Musa Dover
  • Patent number: 6383574
    Abstract: A method for forming a magnetoresistive (MR) layer first employs a substrate over which is formed a magnetoresistive (MR) layer formed of a magnetoresistive (MR) material. There is then ion implanted selectively, while employing an ion implant method, the magnetoresistive (MR) layer to form: (1) an ion implanted portion of the magnetoresistive (MR) layer formed of an ion implanted magnetoresistive (MR) material; and (2) an adjoining non ion implanted portion of the magnetoresistive (MR) layer formed of the magnetoresistive (MR) material, where the ion implanted magnetoresistive (MR) material is a non magnetoresistive (MR) material. The method may be employed for forming within magnetoresistive (MR) sensor elements magnetoresistive (MR) layers with enhanced dimensional uniformity, and in particular enhanced overlay dimensional uniformity.
    Type: Grant
    Filed: July 23, 1999
    Date of Patent: May 7, 2002
    Assignee: Headway Technologies, Inc.
    Inventors: Cherng-Chyi Han, Rong-Fu Xiao, Mao-Min Chen, Po-Kang Wang
  • Patent number: 6373667
    Abstract: A method for fabricating a soft adjacent layer (SAL) magnetoresistive (MR) sensor element and several soft adjacent layer (SAL) magnetoresistive (MR) sensor elements which may be fabricated employing the method. There is first provided a substrate. There is formed over the substrate a dielectric layer, where the dielectric layer has a first surface of the dielectric layer and a second surface of the dielectric layer opposite the first surface of the dielectric layer. There is also formed over the substrate a magnetoresistive (MR) layer contacting the first surface of the dielectric layer. There is also formed over the substrate a soft adjacent layer (SAL), where the soft adjacent layer (SAL) has a first surface of the soft adjacent layer (SAL) and a second surface of the soft adjacent layer (SAL). The first surface of the soft adjacent layer (SAL) contacts the second surface of the dielectric layer.
    Type: Grant
    Filed: August 14, 2000
    Date of Patent: April 16, 2002
    Assignee: Headway Technologies, Inc.
    Inventors: Cherng-Chyi Han, Mao-Min Chen, Cheng Tzong Horng, Po-Kang Wang, Chyu Jiuh Torng, Kochan Ju, Yimin Guo
  • Patent number: 6358635
    Abstract: A magnetic shielding element for a magnetic recording and sensing device which prevents the problem of pop-corn noise or covariance of amplitude noise in the magnetic sensing device. The shielding element has a layer of antiferromagnetic exchange material formed on a layer of single domain first ferromagnetic material. The single domain first ferromagnetic material is stabilized by the antiferromagnetic exchange material. A layer of non-magnetic metal is then formed on the layer of antiferromagnetic exchange material and a layer of second ferromagnetic material is formed on the layer of non-magnetic metal to complete the shielding element. When the single domains of the first ferromagnetic material are disturbed by the strong magnetic fields of a write cycle they relax with a relaxation time of pico seconds and are fully relaxed before a read cycle begins.
    Type: Grant
    Filed: December 20, 1999
    Date of Patent: March 19, 2002
    Assignee: Headway Technologies, Inc.
    Inventors: Tai Min, Otto Voegeli, Rongfu Xiao, Cherng-Chyi Han, Po-Kang Wang