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).
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Patent number: 8256096Abstract: 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: GrantFiled: October 18, 2007Date of Patent: September 4, 2012Assignees: Headway Technologies, Inc., TDK CorporationInventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
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Patent number: 8087157Abstract: 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: GrantFiled: October 18, 2007Date of Patent: January 3, 2012Assignees: Headway Technologies, Inc., TDK CorporationInventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
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Patent number: 7864490Abstract: 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: GrantFiled: September 18, 2007Date of Patent: January 4, 2011Assignee: Headway Technologies, Inc.Inventors: Jeiwei Chang, Stuart Kao, Chao Peng Chen, Chunping Luo, Kochan Ju, Min Li
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Patent number: 7810227Abstract: 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: GrantFiled: October 18, 2007Date of Patent: October 12, 2010Assignees: Headway Technologies, Inc., TDK CorporationInventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
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Publication number: 20080050615Abstract: 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: ApplicationFiled: September 18, 2007Publication date: February 28, 2008Inventors: Jeiwei Chang, Stuart Kao, Chao Chen, Chunping Luo, Kochan Ju, Min Li
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Publication number: 20080043378Abstract: 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: ApplicationFiled: October 18, 2007Publication date: February 21, 2008Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jei-Wei Chang
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Publication number: 20080040914Abstract: 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: ApplicationFiled: October 18, 2007Publication date: February 21, 2008Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
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Publication number: 20080040915Abstract: 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: ApplicationFiled: October 18, 2007Publication date: February 21, 2008Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
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Publication number: 20080034576Abstract: 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: ApplicationFiled: October 18, 2007Publication date: February 14, 2008Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
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Patent number: 7320170Abstract: 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: GrantFiled: April 20, 2004Date of Patent: January 22, 2008Assignees: Headway Technologies, Inc., TDK CorporationInventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jei-Wei Chang
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Patent number: 7279269Abstract: 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: GrantFiled: December 12, 2003Date of Patent: October 9, 2007Assignee: Headway Technologies, Inc.Inventors: Jeiwei Chang, Stuart Kao, Chao Peng Chen, Chunping Luo, Kochan Ju, Min Li
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Publication number: 20050231856Abstract: 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: ApplicationFiled: April 20, 2004Publication date: October 20, 2005Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
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Publication number: 20050130070Abstract: 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: ApplicationFiled: December 12, 2003Publication date: June 16, 2005Inventors: Jeiwei Chang, Stuart Kao, Chao Chen, Chunping Luo, Kochan Ju, Min Li
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Patent number: 6905811Abstract: 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: GrantFiled: April 22, 2003Date of Patent: June 14, 2005Assignee: Headway Technologies, Inc.Inventors: Chao Peng Chen, Chunping Luo, Stuart Kao, Jei-Wei Chang
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Publication number: 20040214109Abstract: 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: ApplicationFiled: April 22, 2003Publication date: October 28, 2004Applicant: Headway Technologies, Inc.Inventors: Chao Peng Chen, Chunping Luo, Stuart Kao, Jei-Wei Chang