Patents by Inventor Chivukula Subrahmanyam
Chivukula Subrahmanyam 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: 6726545Abstract: A linear polishing apparatus for polishing a semiconductor substrate including a novel polishing belt arrangement with at least two polishing belts forming a continuous loop. Each belt having an outside polishing surface and an inside smooth surface. The belts are spaced alongside each other sharing a common axis at each end. The belts are looped around a pair of rollers making up a driver roller at one end and a driven roller at the other end. A platen member interposes each belt and is placed between the pairs of rollers. The platen provides a polishing plane and supporting surface for the polishing belts. The polishing plane includes a plurality of holes communicating with an elongated plenum chamber underlying the plane. The chamber supplies a compressed gas to impart an upward pressure against the polishing belts. The driver rollers are coupled to separate motors to independently drive and control at least said two of the polishing belts.Type: GrantFiled: April 26, 2002Date of Patent: April 27, 2004Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Subramanian Balakumar, Chen Feng, Victor Lim, Paul Proctor, Mukhopadhyay Madhusudan, Chivukula Subrahmanyam, Yelehanka Ramachandramurthy Pradeep
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Patent number: 6689653Abstract: Methods of protecting, and increasing the thickness of, the oxidized silicon nitride (ON), component of an oxidized silicon nitride on silicon oxide (ONO), layer of a non-volatile memory device, during the hydrofluoric (HF), acid type procedures used for peripheral devices simultaneously fabricated with the non-volatile memory device, has been developed. A first method features a silicon nitride layer located only overlying the ONO layer of the non-volatile memory device, formed prior to HF type pre-clean procedures performed prior to gate oxidation procedures used for peripheral devices. After the gate oxidation procedures the silicon nitride capping layer is selectively removed. A second method features a polysilicon capping layer again located only overlying the ONO layer of the non-volatile memory device, again formed prior to HF type pre-clean procedures.Type: GrantFiled: June 18, 2003Date of Patent: February 10, 2004Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Xavier Teo Leng Seah, Chivukula Subrahmanyam, Rajan Rajgopal
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Publication number: 20030203710Abstract: A linear polishing apparatus for polishing a semiconductor substrate including a novel polishing belt arrangement with at least two polishing belts forming a continuous loop. Each belt having an outside polishing surface and an inside smooth surface The belts are spaced alongside each other sharing a common axis at each end. The belts are looped around a pair of rollers making up a driver roller at one end and a driven roller at the other end. A platen member interposes each belt and is placed between the pairs of rollers. The platen provides a polishing plane and supporting surface for the polishing belts. The polishing plane includes a plurality of holes communicating with an elongated plenum chamber underlying the plane. The chamber supplies a compressed gas to impart an upward pressure against the polishing belts. The driver rollers are coupled to separate motors to independently drive and control at least said two of the polishing belts.Type: ApplicationFiled: April 26, 2002Publication date: October 30, 2003Applicant: Chartered Semiconductor Manufacturing Ltd.Inventors: Subramanian Balakumar, Chen Feng, Victor Seng-Keong Lim, Paul Proctor, Mukhopadhyay Madhusudan, Chivukula Subrahmanyam, Yelehanka Ramachandramurthy Pradeep
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Publication number: 20030090600Abstract: A light shield apparatus and formation method for preventing the transmission of incident light towards active devices of the display. In one embodiment, the present invention recites patterning a second metal layer to form a plurality of second metal structures. The present embodiment also recites depositing an intermetal dielectric layer above the plurality of second metal structures. Subsequently, the present embodiment deposits a light absorbing antireflective coating material above the intermetal dielectric layer to form a light shield followed by another planarized IMD layer such that transmission of incident light towards underlying active devices is reduced. The present embodiment also performs the step of forming a plurality of metal pixels above the antireflective coating material wherein adjacent ones of the plurality of metal pixels have a gap region disposed therebetween.Type: ApplicationFiled: November 13, 2001Publication date: May 15, 2003Applicant: CHARTERED SEMICONDUCTORS MANUFACTURED LIMITEDInventors: Xavier Seah Teo Leng, Chivukula Subrahmanyam
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Patent number: 6399448Abstract: A method for forming a multiple thickness gate oxide layer by implanting nitrogen ions in a first area of a semiconductor substrate while a second area of the semiconductor substrate is masked; implanting argon ions into the second area of the semiconductor substrate while the first area of the semiconductor substrate is masked; and thermally growing a gate oxide layer wherein, the oxide growth is retarded in the first area and enhanced in the second area. A threshold voltage implant and/or an anti-punchthrough implant can optionally be implanted into the semiconductor substrate prior to the nitrigen implant using the same implant mask as the nitrogen implant for a low voltage gate, and prior to the argon implant using the same implant mask as the argonm implant for a high voltage gate, further reducing processing steps.Type: GrantFiled: November 19, 1999Date of Patent: June 4, 2002Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Madhusudan Mukhopadhyay, Chivukula Subrahmanyam, Yelehanka Ramachandramurthy Pradeep
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Patent number: 6337262Abstract: A new method is provided for the integration of the of T-top gate process. Active regions are defined and bounded by STI's on the surface of a substrate. The pad oxide is removed from the substrate and replaced by a layer of SAC oxide. A thin layer of nitride is deposited that covers the surface of the created layer of SAC oxide and the surface of the STI regions. A layer of TEOS is deposited and etched defining the regions where the gate electrodes need to be formed. Gate spacers are next formed on the sidewalls of the openings that have been created in the layer of TEOS. The required implants (such as channel implant and threshold implant) are performed, the gate structure is then grown in the openings that have been created in the layer of TEOS. After the gate structure has been completed, the surface of the created structure is polished and the remaining layer of TEOS is removed. Source and drain regions implants can now be performed, LDD regions are implanted using a tilted implant.Type: GrantFiled: March 6, 2000Date of Patent: January 8, 2002Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Yelehanka Ramachandramurthy Pradeep, Chivukula Subrahmanyam, Vijai Kumar Chhagan, Henry Gerung
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Patent number: 6284613Abstract: A method for a T-gate and salicide process that allows narrow bottom gate widths below 0.25 &mgr;m and wide top gate widths to allow silicide gate contacts on the top of the T-gate. A dummy gate composed of an insulating material is formed over the substrate. Then we form LDD regions adjacent to the dummy gate preferably by ion implanting f (I/I) impurity ions into the substrate using the dummy gate as a mask. A pad oxide layer and dielectric layer are formed over the substrate surface. The dielectric layer over the dummy gate is removed preferably by a CMP process. We then remove the dummy gate to form a gate opening exposing the substrate surface. A gate dielectric layer is formed over the substrate surface in the gate opening. We form a polysilicon layer over the dielectric layer and the substrate surface in the gate opening. The polysilicon layer is patterned to form a T-gate. The dielectric layer is removed. We forming source/drain (S/D) regions adjacent to the T-gate by an Ion implant process.Type: GrantFiled: November 5, 1999Date of Patent: September 4, 2001Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Chivukula Subrahmanyam, Yelehanka Ramachandramurthy Pradeep, Ramakrishnan Rajagopal
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Patent number: 6248006Abstract: A new apparatus is provided that allows for uniform polishing of semiconductor surfaces. The single polishing pad of conventional CMP methods is divided into a split pad, the split pad allows for separate adjustments of CMP control parameters across the surface of the wafer. These adjustments can extend from the center of the wafer to its perimeter (along the radius of the wafer) thereby allowing for the elimination of conventional problems of non-uniformity of polishing between the center of the surface that is polished and the perimeter of the surface that is polished.Type: GrantFiled: January 24, 2000Date of Patent: June 19, 2001Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Madhusudan Mukhopadhyay, Subramanian Balakumar, Chivukula Subrahmanyam, Yelehanka Ramachandramurthy Pradeep
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Patent number: 5747369Abstract: A method is described for forming capacitors in integrated circuits by making the capacitors concurrently with the fabrication of the interconnection wiring levels. A single additional photolithographic step and two depositions are required to form capacitors within each wiring level. A key feature of the invention is the use of an etch-stop to protect the capacitor dielectric during contact or via etching. The storage plates of the capacitor are formed from two successive conductor levels which can include polysilicon levels as well. The process is particularly suited to the manufacture of logic circuits and can be used effectively in MOSFET, bipolar and BiCMOS processes.Type: GrantFiled: January 13, 1997Date of Patent: May 5, 1998Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Arjun Kumar Kantimahanti, Chivukula Subrahmanyam, Mei Sheng Zhou