Patents by Inventor Chao Peng Chen
Chao Peng Chen 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: 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: 20070042299Abstract: It is very difficult to produce a negative wall angle from either negative or positive-tone chemically amplified resists, especially by e-beam lithography. This problem has now been overcome by first forming a photoresist pedestal in the conventional way, followed by flood exposing with electrons. Then, a second development treatment is given. This results in removal of additional material from the sidewalls, said removal being greatest at the substrate and least at the pedestal's top surface, resulting in negatively sloping sidewalls. Application of this method to a process for forming a pole tip for a vertical magnetic writer is also discussed.Type: ApplicationFiled: October 27, 2006Publication date: February 22, 2007Inventors: Chao-Peng Chen, Jei-Wei Chang, Xiaohong Yang
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Patent number: 7134182Abstract: Conventional liftoff processes used to define track width in magnetic read heads can produce an uneven etch-depth of dielectric materials around the sensor and cause shorting to the overlay top lead layer. This problem has been overcome by printing the images of track width and stripe height onto an intermediate layer to form a hard mask. Through this hard mask, the GMR stack can be selectively etched and then back-filled with a high-resistivity material by using newly developed electroless plating processes.Type: GrantFiled: November 17, 2003Date of Patent: November 14, 2006Assignee: Headway Technologies, Inc.Inventors: Jei-Wei Chang, Chao-Peng Chen, Youfeng Zheng
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Publication number: 20060249392Abstract: A process for cathodically reducing unwanted Fe+3 ions to needed Fe+2 ions in an acidic ferrous based plating bath without reducing agents is disclosed. An auxiliary potential of 0.1 to 0.3 volts vs. SCE is applied between the working electrode and a reference electrode and can reduce the molar ratio [Fe+3]/[Fe+2] to 1 ppm without depositing Fe or other metals on the working electrode or causing hydrogen evolution. The process is applicable to electroplating soft magnetic films such as NiFe, FeCo, and CoNiFe and can be performed during plating or during cell idling. The process is cost effective by reducing the amount of hazardous waste and tool down time due to routine solution swap. Other benefits are improved uniformity in composition and thickness of plated films because issues associated with decomposed reducing agents are avoided.Type: ApplicationFiled: May 5, 2005Publication date: November 9, 2006Inventors: Chao-Peng Chen, Jas Chudasama, Situan Lam
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Patent number: 7132221Abstract: It is very difficult to produce a negative wall angle from either negative or positive-tone chemically amplified resists, especially by e-beam lithography. This problem has now been overcome by first forming a photoresist pedestal in the conventional way, followed by flood exposing with electrons. Then, a second development treatment is given. This results in removal of additional material from the sidewalls, said removal being greatest at the substrate and least at the pedestal's top surface, resulting in negatively sloping sidewalls. Application of this method to a process for forming a pole tip for a vertical magnetic writer is also discussed.Type: GrantFiled: September 12, 2003Date of Patent: November 7, 2006Assignee: Headway Technologies, Inc.Inventors: Chao-Peng Chen, Jei-Wei Chang, Xiaohong Yang
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Patent number: 7118680Abstract: A method for fabricating a current-perpendicular-to-plane (CPP) giant magnetoresistive (GMR) sensor of the synthetic spin valve type is provided, the method including an electron-beam lithographic process employing both primary and secondary electron absorption and first and second self-aligned lift-off processes for patterning the capped ferromagnetic free layer and the conducting, non-magnetic spacer layer. The sensor so fabricated has reduced resistance and increased sensitivity.Type: GrantFiled: November 20, 2003Date of Patent: October 10, 2006Assignee: Headway Technologies, Inc.Inventors: Jei-Wei Chang, Chao-Peng Chen, Min Li, Kochan Ju
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Patent number: 7111386Abstract: A major problem in Lead Overlay design for GMR structures is that the magnetic read track width is wider than the physical read track width. This is due to high interfacial resistance between the leads and the GMR layer which is an unavoidable side effect of prior art methods. The present invention uses electroplating preceded by a wet etch to fabricate the leads. This approach requires only a thin protection layer over the GMR layer to ensure that interface resistance is minimal. Using wet surface cleaning avoids sputtering defects and plating is compatible with this so the cleaned surface is preserved Only a single lithography step is needed to define the track since there is no re-deposition involved.Type: GrantFiled: November 3, 2005Date of Patent: September 26, 2006Assignee: Headway Technologies, Inc.Inventors: Chao-Peng Chen, Kevin Lin, Jei-Wei Chang, Kochan Ju, Hui-Chuan Wang
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Publication number: 20060048375Abstract: A major problem in Lead Overlay design for GMR structures is that the magnetic read track width is wider than the physical read track width. This is due to high interfacial resistance between the leads and the GMR layer which is an unavoidable side effect of prior art methods. The present invention uses electroplating preceded by a wet etch to fabricate the leads. This approach requires only a thin protection layer over the GMR layer to ensure that interface resistance is minimal. Using wet surface cleaning avoids sputtering defects and plating is compatible with this so the cleaned surface is preserved Only a single lithography step is needed to define the track since there is no re-deposition involved.Type: ApplicationFiled: November 3, 2005Publication date: March 9, 2006Inventors: Chao-Peng Chen, Kevin Lin, Jei-Wei Chang, Kochan Ju, Hui-Chuan Wang
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Publication number: 20060024618Abstract: A method for forming a bi-layer lift-off mask, including a hardened photoresistive stencil layer on a PMGI layer, for use in fabricating GMR read-head sensors with trackwidths of less than 0.1 microns and TMJ MRAM devices of similar critical dimensions. The stencil portion of the mask includes a narrow portion with sharply defined edge and corners which are formed, without rounding or extreme undercut, by a photolithographic process which includes the formation, in a first development process, of auxiliary pattern pieces over the corners of the stencil and a subsequent oxidation in ozone for removing those auxiliary pattern pieces and obtaining sharply defined edge and corners and a controlled dissolution of the PMGI layer.Type: ApplicationFiled: July 28, 2004Publication date: February 2, 2006Inventors: Chao-Peng Chen, Rina Kaji, Jei-Wei Chang
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Patent number: 6973712Abstract: A major problem in Lead Overlay design for GMR structures is that the magnetic read track width is wider than the physical read track width. This is due to high interfacial resistance between the leads and the GMR layer which is an unavoidable side effect of prior art methods. The present invention uses electroplating preceded by a wet etch to fabricate the leads. This approach requires only a thin protection layer over the GMR layer to ensure that interface resistance is minimal. Using wet surface cleaning avoids sputtering defects and plating is compatible with this so the cleaned surface is preserved Only a single lithography step is needed to define the track since there is no re-deposition involved.Type: GrantFiled: March 7, 2002Date of Patent: December 13, 2005Assignee: Headway Technologies, Inc.Inventors: Chao-Peng Chen, Kevin Lin, Jei-Wei Chang, Kochan Ju, Hui-Chuan Wang
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Publication number: 20050233258Abstract: A method for forming a bi-layer lift-off mask for use in fabricating GMR read-head sensors with trackwidths of less than 0.1 microns. The mask layers are formed symmetrically on each other, each layer of the mask having a novel dog-bone shape and the lower mask layer being substantially undercut relative to the upper mask layer. The central portion of the lower mask layer forms a narrow ridge that maintains the upper mask layer at a fixed height above a substrate, thereby avoiding problems associated with bi-layer lift-off masks of the prior art. The method of forming the lower ridge requires a carefully controlled undercutting of the lower mask layer, which is accomplished by using an ozone-assisted oxidation process.Type: ApplicationFiled: April 20, 2004Publication date: October 20, 2005Inventors: Chao-Peng Chen, Rina Kaji, Jei-Wei Chang
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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: 20050111143Abstract: A method for fabricating a current-perpendicular-to-plane (CPP) giant magnetoresistive (GMR) sensor of the synthetic spin valve type is provided, the method including an electron-beam lithographic process employing both primary and secondary electron absorption and first and second self-aligned lift-off processes for patterning the capped ferromagnetic free layer and the conducting, non-magnetic spacer layer. The sensor so fabricated has reduced resistance and increased sensitivity.Type: ApplicationFiled: November 20, 2003Publication date: May 26, 2005Inventors: Jei-Wei Chang, Chao-Peng Chen, Min Li, Kochan Ju
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Publication number: 20050106509Abstract: As the critical dimensions of liftoff patterns grow smaller, it becomes increasingly more difficult to make liftoff resists that have the required resolution. This problem has been overcome by use of a combination of ion beam processing and ozone slimming to form lift-off patterns with undercuts from a single layer of photoresist. The ion beam process serves to harden the top portion of the resist while the ozone is used to oxidize and erode the lower portion resist sidewall to form the undercut.Type: ApplicationFiled: November 14, 2003Publication date: May 19, 2005Inventors: Jei-Wei Chang, Chao-Peng Chen, Chunping Luo, Shou-Chen Kao
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Publication number: 20050102820Abstract: Conventional liftoff processes used to define track width in magnetic read heads can produce an uneven etch-depth of dielectric materials around the sensor and cause shorting to the overlay top lead layer. This problem has been overcome by printing the images of track width and stripe height onto an intermediate layer to form a hard mask. Through this hard mask, the GMR stack can be selectively etched and then back-filled with a high-resistivity material by using newly developed electroless plating processes.Type: ApplicationFiled: November 17, 2003Publication date: May 19, 2005Inventors: Jei-Wei Chang, Chao-Peng Chen, Youfeng Zheng
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Publication number: 20050058952Abstract: It is very difficult to produce a negative wall angle from either negative or positive-tone chemically amplified resists, especially by e-beam lithography. This problem has now been overcome by first forming a photoresist pedestal in the conventional way, followed by flood exposing with electrons. Then, a second development treatment is given. This results in removal of additional material from the sidewalls, said removal being greatest at the substrate and least at the pedestal's top surface, resulting in negatively sloping sidewalls. Application of this method to a process for forming a pole tip for a vertical magnetic writer is also discussed.Type: ApplicationFiled: September 12, 2003Publication date: March 17, 2005Inventors: Chao-Peng Chen, Jei-Wei Chang, Xiaohong Yang
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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
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Publication number: 20030167626Abstract: A major problem in Lead Overlay design for GMR structures is that the magnetic read track width is wider than the physical read track width. This is due to high interfacial resistance between the leads and the GMR layer which is an unavoidable side effect of prior art methods. The present invention uses electroplating preceded by a wet etch to fabricate the leads. This approach requires only a thin protection layer over the GMR layer to ensure that interface resistance is minimal. Using wet surface cleaning avoids sputtering defects and plating is compatible with this so the cleaned surface is preserved Only a single lithography step is needed to define the track since there is no re-deposition involved.Type: ApplicationFiled: March 7, 2002Publication date: September 11, 2003Applicant: Headway Technologies, Inc.Inventors: Chao-Peng Chen, Kevin Lin, Jei-Wei Chang, Kochan Ju, Hui-Chuan Wang
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Patent number: 6476963Abstract: Photographic binoculars include binoculars and a tube with a camera detachably connected to the tube. A focus adjusting mechanism of the binoculars correspond to a focus adjusting mechanism of the tube so that the adjustment to the focal length of the binoculars simultaneously adjusts the focal length of the tube. The camera is able to record an image of a subject observed from the binoculars.Type: GrantFiled: October 16, 2001Date of Patent: November 5, 2002Assignee: Navitek Technology Inc.Inventor: Chao-Peng Chen
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Patent number: 6156185Abstract: Disclosed is a method of reactivating a deactivated anode that has a coating of a noble metal or noble metal oxide on a substrate. A coating of a noble metal is deposited on the anode electrolessly. The noble metal in the deposited coating can be platinum, palladium, iridium, rhodium, ruthenium, osmium, or a mixture thereof.Type: GrantFiled: June 11, 1999Date of Patent: December 5, 2000Assignee: Occidental Chemical CorporationInventors: Chao-Peng Chen, Tilak V. Bommaraju