Patents by Inventor Stuart Kao

Stuart Kao 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: 8256096
    Abstract: Using a beam of xenon ions together with a suitable mask, a stack is ion milled until a part of it, no more than about 0.1 microns thick, has been removed so that a pedestal having sidewalls, including a vertical section and a shortened taper portion, has been formed. This is followed by formation of conductive lead layers as needed. Using xenon as the sputtering gas enables the point at which milling is terminated to be more precisely controlled.
    Type: Grant
    Filed: October 18, 2007
    Date of Patent: September 4, 2012
    Assignees: Headway Technologies, Inc., TDK Corporation
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
  • Patent number: 8087157
    Abstract: Using a beam of xenon ions together with a suitable mask, a MTJ stack is ion milled until a part of it, no more than about 0.1 microns thick, has been removed so that a pedestal, having sidewalls comprising a vertical section that includes all of the free layer, has been formed. This is followed by formation of the longitudinal bias and conductive lead layers in the usual way. Using xenon as the sputtering gas enables the point at which milling is terminated to be more precisely controlled.
    Type: Grant
    Filed: October 18, 2007
    Date of Patent: January 3, 2012
    Assignees: Headway Technologies, Inc., TDK Corporation
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
  • Patent number: 7864490
    Abstract: The series resistance of a CPP GMR stack can be reduced by shaping it into a small upper, on a somewhat larger, lower part. Because of the sub-micron dimensions involved, good alignment between these is normally difficult to achieve. The present invention discloses a self-alignment process based on first laying down a mask that will determine the shape of the top part. Ion beam etching is then initiated, the ion beam being initially applied from one side only at an angle to the surface normal. During etching, all material on the near side of the mask gets etched but, on the far side, only material that is outside the mask's shadow gets removed so, depending on the beam's angle, the size of the lower part is controlled and the upper part is precisely centrally aligned above it.
    Type: Grant
    Filed: September 18, 2007
    Date of Patent: January 4, 2011
    Assignee: Headway Technologies, Inc.
    Inventors: Jeiwei Chang, Stuart Kao, Chao Peng Chen, Chunping Luo, Kochan Ju, Min Li
  • Patent number: 7810227
    Abstract: Using a beam of xenon ions together with a suitable mask, a GMR stack is ion milled until a part of it, no more than about 0.1 microns thick, has been removed so that a pedestal, having sidewalls comprising a vertical section that includes all of the free layer, has been formed. This is followed by formation of the dielectric and conductive lead layers in the usual way. Using xenon as the sputtering gas enables the point at which milling is terminated to be more precisely controlled.
    Type: Grant
    Filed: October 18, 2007
    Date of Patent: October 12, 2010
    Assignees: Headway Technologies, Inc., TDK Corporation
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
  • Publication number: 20080050615
    Abstract: The series resistance of a CPP GMR stack can be reduced by shaping it into a small upper, on a somewhat larger, lower part. Because of the sub-micron dimensions involved, good alignment between these is normally difficult to achieve. The present invention discloses a self-alignment process based on first laying down a mask that will determine the shape of the top part. Ion beam etching is then initiated, the ion beam being initially applied from one side only at an angle to the surface normal. During etching, all material on the near side of the mask gets etched but, on the far side, only material that is outside the mask's shadow gets removed so, depending on the beam's angle, the size of the lower part is controlled and the upper part is precisely centrally aligned above it.
    Type: Application
    Filed: September 18, 2007
    Publication date: February 28, 2008
    Inventors: Jeiwei Chang, Stuart Kao, Chao Chen, Chunping Luo, Kochan Ju, Min Li
  • Publication number: 20080043378
    Abstract: We describe a family of magnetic read heads that each includes a GMR or MTJ stack. A part, no more than about 0.1 microns thick, has been removed from this stack a to form a pedestal having sidewalls comprising a vertical section that includes all of the free layer.
    Type: Application
    Filed: October 18, 2007
    Publication date: February 21, 2008
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jei-Wei Chang
  • Publication number: 20080040914
    Abstract: Using a beam of xenon ions together with a suitable mask, a GMR stack is ion milled until a part of it, no more than about 0.1 microns thick, has been removed so that a pedestal, having sidewalls comprising a vertical section that includes all of the free layer, has been formed. This is followed by formation of the longitudinal bias and conductive lead layers in the usual way. Using xenon as the sputtering gas enables the point at which milling is terminated to be more precisely controlled.
    Type: Application
    Filed: October 18, 2007
    Publication date: February 21, 2008
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
  • Publication number: 20080040915
    Abstract: Using a beam of xenon ions together with a suitable mask, a stack is ion milled until a part of it, no more than about 0.1 microns thick, has been removed so that a pedestal having sidewalls, including a vertical section and a shortened taper portion, has been formed. This is followed by formation of conductive lead layers as needed. Using xenon as the sputtering gas enables the point at which milling is terminated to be more precisely controlled.
    Type: Application
    Filed: October 18, 2007
    Publication date: February 21, 2008
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
  • Publication number: 20080034576
    Abstract: Using a beam of xenon ions together with a suitable mask, a MTJ stack is ion milled until a part of it, no more than about 0.1 microns thick, has been removed so that a pedestal, having sidewalls comprising a vertical section that includes all of the free layer, has been formed. This is followed by formation of the longitudinal bias and conductive lead layers in the usual way. Using xenon as the sputtering gas enables the point at which milling is terminated to be more precisely controlled.
    Type: Application
    Filed: October 18, 2007
    Publication date: February 14, 2008
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
  • Patent number: 7320170
    Abstract: Using a beam of xenon ions together with a suitable mask, a GMR stack is ion milled until a part of it, no more than about 0.1 microns thick, has been removed so that a pedestal, having sidewalls comprising a vertical section that includes all of the free layer, has been formed. This is followed by formation of the longitudinal bias and conductive lead layers in the usual way. Using xenon as the sputtering gas enables the point at which milling is terminated to be more precisely controlled.
    Type: Grant
    Filed: April 20, 2004
    Date of Patent: January 22, 2008
    Assignees: Headway Technologies, Inc., TDK Corporation
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jei-Wei Chang
  • Patent number: 7279269
    Abstract: The series resistance of a CPP GMR stack can be reduced by shaping it into a small upper, on a somewhat larger, lower part. Because of the sub-micron dimensions involved, good alignment between these is normally difficult to achieve. The present invention discloses a self-alignment process based on first laying down a mask that will determine the shape of the top part. Ion beam etching is then initiated, the ion beam being initially applied from one side only at an angle to the surface normal. During etching, all material on the near side of the mask gets etched but, on the far side, only material that is outside the mask's shadow gets removed so, depending on the beam's angle, the size of the lower part is controlled and the upper part is precisely centrally aligned above it.
    Type: Grant
    Filed: December 12, 2003
    Date of Patent: October 9, 2007
    Assignee: Headway Technologies, Inc.
    Inventors: Jeiwei Chang, Stuart Kao, Chao Peng Chen, Chunping Luo, Kochan Ju, Min Li
  • Publication number: 20050231856
    Abstract: A GMR read pillar formed by ion milling has both vertical and sloping sidewall sections with the free layer normally being located within the latter. Using xenon as the sputtering gas enables the vertical section of the pedestal to be made longer, relative to the sloping portion, without requiring an increase in the sputtering rate, so the free layer can have vertical sidewalls. This allows the point at which milling is terminated to be controlled more precisely and, by more precisely defining the width of the free layer, also improves design tolerances.
    Type: Application
    Filed: April 20, 2004
    Publication date: October 20, 2005
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
  • Publication number: 20050130070
    Abstract: The series resistance of a CPP GMR stack can be reduced by shaping it into a small upper, on a somewhat larger, lower part. Because of the sub-micron dimensions involved, good alignment between these is normally difficult to achieve. The present invention discloses a self-alignment process based on first laying down a mask that will determine the shape of the top part. Ion beam etching is then initiated, the ion beam being initially applied from one side only at an angle to the surface normal. During etching, all material on the near side of the mask gets etched but, on the far side, only material that is outside the mask's shadow gets removed so, depending on the beam's angle, the size of the lower part is controlled and the upper part is precisely centrally aligned above it.
    Type: Application
    Filed: December 12, 2003
    Publication date: June 16, 2005
    Inventors: Jeiwei Chang, Stuart Kao, Chao Chen, Chunping Luo, Kochan Ju, Min Li
  • Patent number: 6905811
    Abstract: As feature sizes approach 0.1 ?m or smaller, reduction of line edge roughness (LER) becomes increasingly important. Significant reductions in edge roughness have been achieved by applying a second Ebeam exposure after the initial one that is used to define the pattern. After this second blanket exposure a longer heat treatment and a stronger development process than before are used. In addition to reducing edge roughness the disclosed treatment allows the CD to be reduced under tight control since the amount of CD reduction is proportional to the second Ebeam dosage.
    Type: Grant
    Filed: April 22, 2003
    Date of Patent: June 14, 2005
    Assignee: Headway Technologies, Inc.
    Inventors: Chao Peng Chen, Chunping Luo, Stuart Kao, Jei-Wei Chang
  • Publication number: 20040214109
    Abstract: As feature sizes approach 0.1 &mgr;m or smaller, reduction of line edge roughness (LER) becomes increasingly important. Significant reductions in edge roughness have been achieved by applying a second Ebeam exposure after the initial one thatis used to define the pattern. After this second blanket exposure a longer heat treatment and a stronger development process than before are used. In addition to reducing edge roughness the disclosed treatment allows the CD to be reduced under tight control since the amount of CD reduction is proportional to the second Ebeam dosage.
    Type: Application
    Filed: April 22, 2003
    Publication date: October 28, 2004
    Applicant: Headway Technologies, Inc.
    Inventors: Chao Peng Chen, Chunping Luo, Stuart Kao, Jei-Wei Chang