Patents by Inventor Uttam Shyamalindu Ghoshal
Uttam Shyamalindu Ghoshal 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: 6907322Abstract: A method and apparatus for characterization of a thermal response of giant magnetoresistive (GMR) sensors in magnetic read/write heads is provided. The method and apparatus make use of a probe to measure temperatures at a base and a tip of the probe. With the method and apparatus, a temperature of magnetic shields of the read/write head are cooled to a temperature lower than an ambient temperature. A current is then applied to the GMR sensor to increase a temperature of an air bearing surface such that the heat flow through the probe is zero. The amount of current applied, the resistance of the GMR sensor, the magnetic shield temperature, and the ambient temperature are used to calculate a thermal conductance of dielectric material in the read/write head. The thermal conductance is then utilized to estimate the signal to noise ratio of the GMR sensor and determine a maximum bandwidth of the read/write head.Type: GrantFiled: November 30, 2000Date of Patent: June 14, 2005Assignee: International Business Machines CorporationInventor: Uttam Shyamalindu Ghoshal
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Patent number: 6893902Abstract: Method and apparatus for thermal management of an integrated circuit. A semiconductor device includes an integrated circuit and an integrated thermoelectric cooler formed on a common substrate. A semiconductor device is fabricated by forming an integrated circuit on a front side of the substrate and forming an integrated thermoelectric cooler on a back side of the substrate. A first thermal sink of semiconductor material capable of absorbing heat from the integrated circuit is formed on the back side of the substrate. N-type thermoelectric elements are formed on contacts formed on the first thermal sink. P-type thermoelectric elements are formed on contacts formed on a second thermal sink of semiconductor material capable of dissipating heat. The p-type and n-type thermoelectric elements are bonded to the contacts on the first and second thermal sinks, respectively, by a flip-chip soldering process.Type: GrantFiled: April 11, 2002Date of Patent: May 17, 2005Assignee: International Business Machines CorporationInventors: Michael James Cordes, Steven Alan Cordes, Uttam Shyamalindu Ghoshal, Errol Wayne Robinson, James Louis Speidell
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Patent number: 6893884Abstract: A method and apparatus for measuring dopant profile of a semiconductor is disclosed. Initially, the temperature of a tip of a probe and the temperature of a semiconductor sample are ascertained. Then, a voltage at a location on a surface of the semiconductor sample is obtained via the tip of the probe. The dopant concentration at the location of the surface of the semiconductor sample is subsequently determined by combining the obtained voltage and the temperature difference between the probe tip and the semiconductor sample. The above-mentioned steps can be repeated in order to generate a dopant profile of the semiconductor.Type: GrantFiled: March 28, 2002Date of Patent: May 17, 2005Assignee: International Business Machines CorporationInventors: Li Shi, Uttam Shyamalindu Ghoshal
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Patent number: 6866415Abstract: A scanning heat flow probe for making quantitative measurements of heat flow through a device under test is provided. In one embodiment the scanning heat flow probe includes an electric current conductor in a cantilever beam connected to a probe tip and coupled to two voltmeter leads. The probe also includes two thermocouple junctions in the cantilever beam electrically isolated from the electric current conductor and the two voltmeter leads. Heat flow is derived quantitatively using only voltage and current measurements. In other forms, the invention relates to the calibration of scanning heat flow probes through a method involving interconnected probes, and relates to the minimization of heat flow measurement uncertainty by probe structure design practices.Type: GrantFiled: January 21, 2003Date of Patent: March 15, 2005Assignee: International Business Machines CorporationInventors: Steven Alan Cordes, David R. DiMilia, James Patrick Doyle, Matthew James Farinelli, Snigdha Ghoshal, Uttam Shyamalindu Ghoshal, Chandler Todd McDowell, Li Shi
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Publication number: 20040262745Abstract: Method and apparatus for thermal management of an integrated circuit. A semiconductor device includes an integrated circuit and an integrated thermoelectric cooler formed on a common substrate. A semiconductor device is fabricated by forming an integrated circuit on a front side of the substrate and forming an integrated thermoelectric cooler on a back side of the substrate. A first thermal sink of semiconductor material capable of absorbing heat from the integrated circuit is formed on the back side of the substrate. N-type thermoelectric elements are formed on contacts formed on the first thermal sink. P-type thermoelectric elements are formed on contacts formed on a second thermal sink of semiconductor material capable of dissipating heat. The p-type and n-type thermoelectric elements are bonded to the contacts on the first and second thermal sinks, respectively, by a flip-chip soldering process.Type: ApplicationFiled: April 11, 2002Publication date: December 30, 2004Inventors: Michael James Cordes, Steven Alan Cordes, Uttam Shyamalindu Ghoshal, Errol Wayne Robinson, James Louis Speidell
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Patent number: 6817761Abstract: A scanning heat flow probe for making quantitative measurements of heat flow through a device under test is provided. In one embodiment the scanning heat flow probe includes an electric current conductor in a cantilever beam connected to a probe tip and coupled to two voltmeter leads. The probe also includes two thermocouple junctions in the cantilever beam electrically isolated from the electric current conductor and the two voltmeter leads. Heat flow is derived quantitatively using only voltage and current measurements. In other forms, the invention relates to the calibration of scanning heat flow probes through a method involving interconnected probes, and relates to the minimization of heat flow measurement uncertainty by probe structure design practices.Type: GrantFiled: April 21, 2003Date of Patent: November 16, 2004Assignee: International Business Machines CorporationInventors: Steven Alan Cordes, David R. DiMilia, James Patrick Doyle, Matthew James Farinelli, Snigdha Ghoshal, Uttam Shyamalindu Ghoshal, Chandler Todd McDowell, Li Shi
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Patent number: 6740600Abstract: A thermoelectric device with improved efficiency is provided. In one embodiment, the thermoelectric device includes a first thermoelement and a second thermoelement electrically coupled to the first thermoelement. An array of first tips are in close physical proximity to, but not necessarily in physical contact with, the first thermoelement at a first set of discrete points. An array of second tips are in close physical proximity to, but not necessarily in physical contact with, the second thermoelement at a second set of discrete points. The first and second conical are constructed entirely from metal, thus reducing parasitic resistances.Type: GrantFiled: February 11, 2002Date of Patent: May 25, 2004Assignee: International Business Machines CorporationInventors: Uttam Shyamalindu Ghoshal, Errol Wayne Robinson
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Patent number: 6712258Abstract: A method for forming a thermoelement for a thermoelectric cooler is provided. In one embodiment a first substrate having a plurality of pointed tips separated by valleys wherein the substrate is covered by a metallic layer, portions of the metallic layer is covered by an insulator, and other portions of the metallic layer are exposed is formed. The other portions of the metallic layer that are exposed are covered with a thermoelectric material overcoat. A second substrate of thermoelectric material is then fused to the pointed tip side of the first substrate by, for example, heating the back of the first substrate to melt the thermoelectric material overcoat or by passing current through the pointed tips to induce Joule heating and thereby melt the thermoelectric material overcoat.Type: GrantFiled: December 13, 2001Date of Patent: March 30, 2004Assignee: International Business Machines CorporationInventor: Uttam Shyamalindu Ghoshal
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Publication number: 20040028117Abstract: A scanning heat flow probe for making quantitative measurements of heat flow through a device under test is provided. In one embodiment the scanning heat flow probe includes an electric current conductor in a cantilever beam connected to a probe tip and coupled to two voltmeter leads. The probe also includes two thermocouple junctions in the cantilever beam electrically isolated from the electric current conductor and the two voltmeter leads. Heat flow is derived quantitatively using only voltage and current measurements. In other forms, the invention relates to the calibration of scanning heat flow probes through a method involving interconnected probes, and relates to the minimization of heat flow measurement uncertainty by probe structure design practices.Type: ApplicationFiled: April 21, 2003Publication date: February 12, 2004Inventors: Steven Alan Cordes, David R. DiMilia, James Patrick Doyle, Matthew James Farinelli, Snigdha Ghoshal, Uttam Shyamalindu Ghoshal, Chandler Todd McDowell, Li Shi
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Publication number: 20040018729Abstract: A thermoelectric device with improved efficiency is provided. In one embodiment, the thermoelectric device includes a first thermoelement and a second thermoelement electrically coupled to the first thermoelement. An array of first tips are in close physical proximity to, but not necessarily in physical contact with, the first thermoelement at a first set of discrete points. An array of second tips are in close physical proximity to, but not necessarily in physical contact with, the second thermoelement at a second set of discrete points. The first and second conical are constructed entirely from metal, thus reducing parasitic resistances.Type: ApplicationFiled: July 1, 2003Publication date: January 29, 2004Inventors: Uttam Shyamalindu Ghoshal, Errol Wayne Robinson
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Patent number: 6679625Abstract: A scanning heat flow probe for making quantitative measurements of heat flow through a device under test is provided. In one embodiment the scanning heat flow probe includes an electric current conductor in a cantilever beam connected to a probe tip and coupled to two voltmeter leads. The probe also includes two thermocouple junctions in the cantilever beam electrically isolated from the electric current conductor and the two voltmeter leads. Heat flow is derived quantitatively using only voltage and current measurements. In other forms, the invention relates to the calibration of scanning heat flow probes through a method involving interconnected probes, and relates to the minimization of heat flow measurement uncertainty by probe structure design practices.Type: GrantFiled: December 17, 2001Date of Patent: January 20, 2004Assignee: International Business Machines CorporationInventors: Steven Alan Cordes, David R. DiMilia, James Patrick Doyle, Matthew James Farinelli, Snigdha Ghoshal, Uttam Shyamalindu Ghoshal, Chandler Todd McDowell, Li Shi
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Patent number: 6661303Abstract: A bidirectional bus and data processing system suitable for suppressing cross talk noise are disclosed. The bidirectional bus includes, a first interconnect line driven by a pair of drivers, a first pair of impedance elements connected between the first line and a second line of the bus, and a second pair of impedance elements connected between the first line and a third line of the bus. In one embodiment, the capacitive coupling per unit length between the first line and the second line is approximately equal to k and the impedance of the first pair of impedance elements is approximately equal to (&ugr;k)−1, where &ugr; is the speed of light through a dielectric in which the first and second lines are located. In one embodiment, the impedance of the first driver is approximately equal to (&ugr;c0)−1, wherein c0 is the self-capacitance of the first line.Type: GrantFiled: November 30, 1999Date of Patent: December 9, 2003Assignee: International Business Machines CorporationInventor: Uttam Shyamalindu Ghoshal
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Patent number: 6652139Abstract: A method of fabricating a scanning heat flow probe for making quantitative measurements of heat flow through a device under test is provided. In one embodiment the scanning heat flow probe includes an electric current conductor in a cantilever beam connected to a probe tip and coupled to two voltmeter leads. The probe also includes two thermocouple junctions in the cantilever beam electrically isolated from the electric current conductor and the two voltmeter leads. Heat flow is derived quantitatively using only voltage and current measurements. The invention also relates to the calibration of scanning heat flow probes through a method involving interconnected probes, and relates to the minimization of heat flow measurement uncertainty by probe structure design practices.Type: GrantFiled: January 21, 2003Date of Patent: November 25, 2003Assignee: International Business Machines CorporationInventors: Steven Alan Cordes, David R. DiMilia, James Patrick Doyle, Matthew James Farinelli, Snigdha Ghoshal, Uttam Shyamalindu Ghoshal, Chandler Todd McDowell, Li Shi
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Patent number: 6650163Abstract: A system and integrated circuit (die) including a clock generator that includes an on-chip inductor and uses the inherent capacitance of the load to generate a sinusoidal clock signal. The inductor is connected between a current source and an inverting switch. The output of the switch is a substantially sinusoidal signal that connected directly to at least a portion of the clock driven circuits without intermediate buffering. In the preferred embodiment, the clock generator is a dual phase design that includes a pair of cross-coupled MOSFET's, a pair of solid state on-chip inductors, and a current source. Each of the on-chip inductors is connected between the current source and the drain of one of the MOSFET's. The outputs of the clock generator are provided directly to the clock inputs of at least a portion of the clock driven circuits on the die.Type: GrantFiled: August 8, 2002Date of Patent: November 18, 2003Assignee: International Business Machines CorporationInventors: Jeffrey L. Burns, Alan James Drake, Uttam Shyamalindu Ghoshal, Kevin John Nowka
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Publication number: 20030186471Abstract: A method and apparatus for measuring dopant profile of a semiconductor is disclosed. Initially, the temperature of a tip of a probe and the temperature of a semiconductor sample are ascertained. Then, a voltage at a location on a surface of the semiconductor sample is obtained via the tip of the probe. The dopant concentration at the location of the surface of the semiconductor sample is subsequently determined by combining the obtained voltage and the temperature difference between the probe tip and the semiconductor sample. The above-mentioned steps can be repeated in order to generate a dopant profile of the semiconductor.Type: ApplicationFiled: March 28, 2002Publication date: October 2, 2003Applicant: International Business Machines CorporationInventors: Li Shi, Uttam Shyamalindu Ghoshal
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Publication number: 20030169798Abstract: A scanning heat flow probe for making quantitative measurements of heat flow through a device under test is provided. In one embodiment the scanning heat flow probe includes an electric current conductor in a cantilever beam connected to a probe tip and coupled to two voltmeter leads. The probe also includes two thermocouple junctions in the cantilever beam electrically isolated from the electric current conductor and the two voltmeter leads. Heat flow is derived quantitatively using only voltage and current measurements. In other forms, the invention relates to the calibration of scanning heat flow probes through a method involving interconnected probes, and relates to the minimization of heat flow measurement uncertainty by probe structure design practices.Type: ApplicationFiled: January 21, 2003Publication date: September 11, 2003Inventors: Steven Alan Cordes, David R. DiMilia, James Patrick Doyle, Matthew James Farinelli, Snigdha Ghoshal, Uttam Shyamalindu Ghoshal, Chandler Todd McDowell, Li Shi
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Patent number: 6613602Abstract: A method and system for forming a thermoelement for a thermoelectric cooler is provided. In one embodiment a substrate having a plurality of pointed tips covered by a metallic layer is formed. Portions of the metallic layer are covered by an insulator and other portions of the metallic layer are exposed. Next, a patterned layer of thermoelectric material is formed by depositions extending from the exposed portions of the metallic layer in the presence of a deposition mask. Finally, a metallic layer is formed to selectively contact the patterned layer of thermoelectric material.Type: GrantFiled: December 13, 2001Date of Patent: September 2, 2003Assignee: International Business Machines CorporationInventors: Emanuel Israel Cooper, Steven Alan Cordes, David R. DiMilia, Bruce Bennett Doris, James Patrick Doyle, Uttam Shyamalindu Ghoshal, Robin Altman Wanner
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Patent number: 6614109Abstract: Method and apparatus for thermal management of an integrated circuit. A semiconductor device includes an integrated circuit and an integrated thermoelectric cooler formed on a common substrate. A semiconductor device is fabricated by forming an integrated circuit on a front side of the substrate and forming an integrated thermoelectric cooler on a back side of the substrate. A first thermal sink of semiconductor material capable of absorbing heat from the integrated circuit is formed on the back side of the substrate. N-type thermoelectric elements are formed on contacts formed on the first thermal sink. P-type thermoelectric elements are formed on contacts formed on a second thermal sink of semiconductor material capable of dissipating heat. The p-type and n-type thermoelectric elements are bonded to the contacts on the first and second thermal sinks, respectively, by a flip-chip soldering process.Type: GrantFiled: February 4, 2000Date of Patent: September 2, 2003Assignee: International Business Machines CorporationInventors: Michael James Cordes, Steven Alan Cordes, Uttam Shyamalindu Ghoshal, Errol Wayne Robinson, James Louis Speidell
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Publication number: 20030156623Abstract: A scanning heat flow probe for making quantitative measurements of heat flow through a device under test is provided. In one embodiment the scanning heat flow probe includes an electric current conductor in a cantilever beam connected to a probe tip and coupled to two voltmeter leads. The probe also includes two thermocouple junctions in the cantilever beam electrically isolated from the electric current conductor and the two voltmeter leads. Heat flow is derived quantitatively using only voltage and current measurements. In other forms, the invention relates to the calibration of scanning heat flow probes through a method involving interconnected probes, and relates to the minimization of heat flow measurement uncertainty by probe structure design practices.Type: ApplicationFiled: January 21, 2003Publication date: August 21, 2003Inventors: Steven Alan Cordes, David R. DiMilia, James Patrick Doyle, Matthew James Farinelli, Snigdha Ghoshal, Uttam Shyamalindu Ghoshal, Chandler Todd McDowell, Li Shi
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Patent number: 6608250Abstract: A thermoelectric device with improved efficiency is provided. In one embodiment, the thermoelectric device includes an electrical conductor thermally coupled to a cold plate and a thermoelement electrically coupled to the electrical conductor. The thermoelement is constructed from a thermoelectric material and has a plurality of tips through which the thermoelement is electrically coupled to the electrical conductor. The thermoelectric tips provide a low resistive connection while minimizing thermal conduction between the electrical conductor and the thermoelement.Type: GrantFiled: December 7, 2000Date of Patent: August 19, 2003Assignee: International Business Machines CorporationInventor: Uttam Shyamalindu Ghoshal