Krishna D Darbha

Address:

18235 NE 111 St, Redmond, WA 98052

VIN:

2HNYD2H21BH524372

Make:

ACURA

Model:

MDX

Year:

2011

US Patent:

6622786, Sep 23, 2003

Filed:

Apr 17, 2002

Appl. No.:

10/125302

Inventors:

Varaprasad V. Calmidi - Vestal NY
Krishna Darbha - Kirkland WA
Sanjeev B. Sathe - Binghamton NY
Jamil A. Wakil - Binghamton NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

F28F 700

US Classification:

165185, 165 803, 165147, 165122, 361697

Abstract:

A heat sink structure is formed by stacking a plurality of heat sink layers. Each layer comprises an array of vertically disposed heat dissipating elements extending from a base plate. Cut outs are formed in each of the base plates to form openings so that when the layers are stacked, each of the ascending successive layers has a larger opening than the layer upon which it rests. Cooling may be by forced air or natural convection. With forced air, air impinges on the top of the stack and into the opening in the base plates. Because of diminishing size of the openings in the stack, a portion of the air is forced out the sides of each layer. With natural convection, air is drawn into the sides of each layer and the hot air at the center flows upwardly through the openings with increasing volume as it rises.

US Patent:

6631078, Oct 7, 2003

Filed:

Jan 10, 2002

Appl. No.:

10/044204

Inventors:

David J. Alcoe - Vestal NY
Varaprasad Venkata Calmidi - Vestal NY
Krishna Darbha - Johnson City NY
Sanjeev Balwant Sathe - Johnson City NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H05K 720

US Classification:

361719, 361710, 257719

Abstract:

A heat dissipating flexible or resilient standoff is mechanically clamped between an electronic module and substrate, such as, PCB. The clamping arrangement comprises a heat sink compressing a thermally conductive flexible interface pad over the upper surface of the electronic module by way of mechanical linkage to the PCB. The heat dissipating flexible standoff provides a force opposing the compression force to thereby reduce stress on solder ball connections between electronic module and PCB. Thermally conductive flexible standoffs in the form of spring arrangements, such as a wire mesh, act to provide heat dissipation by both thermal conduction and thermal convection. A thermally conductive flexible polymer pad and a layer of porous metal foam may also act as thermally conductive standoffs.

US Patent:

6639302, Oct 28, 2003

Filed:

Mar 20, 2002

Appl. No.:

10/103602

Inventors:

Krishna Darbha - Kirkland WA
Miguel A. Jimarez - Newark Valley NY
Matthew M. Reiss - Endwell NY
Sanjeev B. Sathe - Binghamton NY
Charles G. Woychik - Vestal NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H01L 2906

US Classification:

257620, 257618

Abstract:

A method and structure to electrically couple a semiconductor device to a substrate that is divided into a plurality of segments. Alternatively, a semiconductor device may be divided into a plurality of segments and the plurality of segments are electrically coupled to a single substrate.

US Patent:

6649833, Nov 18, 2003

Filed:

Aug 9, 2002

Appl. No.:

10/215451

Inventors:

David V. Caletka - Apalachin NY
Krishna Darbha - Kirkland WA
Donald W. Henderson - Ithaca NY
Lawrence P. Lehman - Endicott NY
George H. Thiel - Endicott NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H05L 2328

US Classification:

174 522, 257738, 22818022

Abstract:

An electronic package is provided including a substrate, a device mounted on the substrate, and a solder member electrically coupling the device to the substrate. The package includes a dielectric material positioned substantially around the solder member which forms a physical connection between the substrate and the device. The volume of the solder member contracts during melting thereof to prevent failure of the physical connection and/or the electrical coupling between the substrate and the device.

US Patent:

6686664, Feb 3, 2004

Filed:

Apr 30, 2001

Appl. No.:

09/845448

Inventors:

David Vincent Caletka - Apalachin NY
Krishna Darbha - Johnson City NY
Donald W. Henderson - Ithaca NY
Lawrence P. Lehman - Endicott NY
George Henry Thiel - Endicott NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H01L 2348

US Classification:

257778, 257772

Abstract:

Solder balls, such as, low melt C4 solder balls undergo volume expansion during reflow. Where the solder balls are encapsulated, expansion pressure can cause damage to device integrity. A volume expansion region in the semiconductor chip substrate beneath each of the solder balls accommodates volume expansion. Air-cushioned diaphgrams, deformable materials and non-wettable surfaces may be used to permit return of the solder during cooling to its original site. A porous medium with voids sufficient to accommodate expansion may also be used.

US Patent:

6905961, Jun 14, 2005

Filed:

Jan 3, 2003

Appl. No.:

10/336579

Inventors:

David Vincent Caletka - Apalachin NY, US
Krishna Darbha - Johnson City NY, US
William Infantolino - Vestal NY, US
Eric Arthur Johnson - Greene NY, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H01L021/44

US Classification:

438667, 438637, 438638, 438639

Abstract:

A flexible chip carrier with contact pads on its upper surface matching those of the chip with said pads conductively connected to land grid array (LGA) pads on its lower surface matching the those of a card or PCB. The chip carrier is provided with a stiffening layer at the LGA interface. The stiffening layer is mechanically attached to the lower surface of the chip carrier. Holes are formed in the stiffening layer to expose the LGA pads. The holes are then filled with a conductive adhesive material. Compliant LGA bumps are applied to the uncured conductive adhesive material which material is then cured.

US Patent:

6989607, Jan 24, 2006

Filed:

Jul 29, 2003

Appl. No.:

10/629469

Inventors:

Krishna Darbha - Johnson City NY, US
Miguel A. Jimarez - Newark Valley NY, US
Matthew M. Reiss - Endwell NY, US
Sanjeev B. Sathe - Binghamton NY, US
Charles G. Woychik - Vestal NY, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H01L 23/48
H01L 23/52
H01L 29/40

US Classification:

257778, 257685, 257723

Abstract:

A method and structure to electrically couple a semiconductor device to a substrate that is divided into a plurality of segments. Alternatively, a semiconductor device may be divided into a plurality of segments and the plurality of segments are electrically coupled to a single substrate.

US Patent:

7086147, Aug 8, 2006

Filed:

Jan 29, 2004

Appl. No.:

10/768836

Inventors:

David Vincent Caletka - Apalachin NY, US
Krishna Darbha - Johnson City NY, US
Donald W. Henderson - Ithaca NY, US
Lawrence P. Lehman - Endicott NY, US
George Henry Thiel - Endicott NY, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H05K 3/34
H01L 23/48

US Classification:

29840, 29843, 29855, 2281791, 22818022, 257778

Abstract:

Solder balls such as, low melt C4 solder balls, undergo volume expansion during reflow, such as may occur during attachment of chip modules to a PCB. Where the solder balls are encapsulated, expansion pressure can cause damage to device integrity. A volume expansion region in the semiconductor chip substrate beneath each of the solder balls accommodated this volume expansion. Air-cushioned diaphgrams, deformable materials and non-wettable surfaces may be used to permit return of the solder during cooling to its original site. A porous medium with voids sufficient to accommodate expansion may also be used.