Thomas T Fagan

US Patent:

59010371, May 4, 1999

Filed:

Jun 18, 1997

Appl. No.:

8/877849

Inventors:

Robin E. Hamilton - Millersville MD
Thomas J. Fagan - Pittsburgh PA
Paul G. Kennedy - Grasonville MD
William S. Woodward - Greensburg PA

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

H05K 720

US Classification:

361699

Abstract:

A closed loop liquid cooling system for an RF transistor module including a plurality of elongated microchannels connected between a pair of coolant manifolds for conducting liquid coolant beneath one or more transistor dies to dissipate the heat generated thereby, a heat exchanger, a miniature circulating pump located on the module, and passive check valves having tapered passages for controlling the flow of coolant in the loop. The valves are truncated tapered passage microchannel valves having no moving parts and are fabricated so as to be a part of either the circulating pump, the coolant manifolds, or the microchannels.

US Patent:

58014420, Sep 1, 1998

Filed:

Jul 22, 1996

Appl. No.:

8/681207

Inventors:

Robin E. Hamilton - Millersville MD
Paul G. Kennedy - Grasonville MD
John Ostop - Severna Park MD
Martin L. Baker - Sykesville MD
Gregory A. Arlow - Eldersburg MD
John C. Golombeck - Gambrills MD
Thomas J Fagan - Pittsburgh PA

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

H01L 2334

US Classification:

257714

Abstract:

Cooling of densely packaged semiconductor devices is achieved by microchannels which extract heat by forced convection and the use of fluid coolant located as close as possible to the heat source. The microchannels maximize heat sink surface area and provides improved heat transfer coefficients, thereby allowing a higher power density of semiconductor devices without increasing junction temperature or decreasing reliability. In its preferred embodiment, a plurality of microchannels are formed directly in the substrate portion of a silicon or silicon carbide chip or die mounted on a ground plane element of a circuit board and where a liquid coolant is fed to and from the microchannels through the ground plane. The microchannels comprise a plurality of closed-ended slots or grooves of generally rectangular cross section. Fabrication methods include deposition and etching, lift-off processing, micromachining and laser cutting techniques.

US Patent:

59982403, Dec 7, 1999

Filed:

May 4, 1998

Appl. No.:

9/071776

Inventors:

Robin E. Hamilton - Millersville MD
Paul G. Kennedy - Grasonville MD
John Ostop - Severna Park MD
Martin L. Baker - Sykesville MD
Gregory A. Arlow - Eldersburg MD
John C. Golombeck - Gambrills MD
Thomas J. Fagan - Pittsburgh PA

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

H01L 2144

US Classification:

438122

Abstract:

Cooling of densely packaged semiconductor devices is achieved by microchannels which extract heat by forced convection and the use of fluid coolant located as close as possible to the heat source. The microchannels maximize heat sink surface area and provides improved heat transfer coefficients, thereby allowing a higher power density of semiconductor devices without increasing junction temperature or decreasing reliability. In its preferred embodiment, a plurality of microchannels are formed directly in the substrate portion of a silicon or silicon carbide chip or die mounted on a ground plane element of a circuit board and where a liquid coolant is fed to and from the microchannels through the ground plane. The microchannels comprise a plurality of closed-ended slots or grooves of generally rectangular cross section. Fabrication methods include deposition and etching, lift-off processing, micromachining and laser cutting techniques.