As the scale of devices becomes small, thermal control and heat dissipation from these devices can be effectively accomplished through the implementation of microchannel passages. The small passages provide a high surface area to volume ratio that enables higher heat transfer rates. High performance microchannel heat exchangers are also attractive in applications where space and/or weight constraints dictate the size of a heat exchanger or where performance enhancement is desired. This survey article provides a historical perspective of the progress made in understanding the underlying mechanisms in single-phase liquid flow and two-phase flow boiling processes and their use in high heat flux removal applications. Future research directions for (i) further enhancing the single-phase heat transfer performance and (ii) enabling practical implementation of flow boiling in microchannel heat exchangers are outlined.

History, Advances, and Challenges in Liquid Flow and Flow Boiling Heat Transfer in Microchannels: A Critical Review

This paper describes a practical implementation of a single-phase Si microchannel cooler designed for cooling very high power chips such as microprocessors. Through the use of multiple heat exchanger zones and optimized cooler fin designs, a unit thermal resistance 10.5 C-mm2 /W from the cooler surface to the inlet water was demonstrated with a fluid pressure drop of <35kPa. Further, cooling of a thermal test chip with a microchannel cooler bonded to it packaged in a single chip module was also demonstrated for a chip power density greater than 300W/cm2. Coolers of this design should be able to cool chips with average power densities of 400W/cm2 or more

A Practical Implementation of Silicon Microchannel Coolers for High Power Chips

The paper describes a practical implementation of a single-phase Si microchannel cooler designed for cooling very high power chips such as microprocessors. Through the use of multiple heat exchanger zones and optimized cooler fin designs, a unit thermal resistance of 10.5 C-mm/sup 2//W from the cooler surface to the inlet water was demonstrated with a fluid pressure drop of less than 35 kPa. Further, cooling of a thermal test chip with a microchannel cooler bonded to it packaged in a single chip module was also demonstrated for a chip power density greater than 300 W/cm/sup 2/. Coolers of this design should be able to cool chips with average power densities of 400 W/cm/sup 2/ or more.

A practical implementation of silicon microchannel coolers for high power chips

The operation of a two-dimensional GaInAsP/InP diode laser array with CW power dissipation up to 500 W/cm/sup 2/ into a Si microchannel heat sink is discussed. The approximately 1*4-mm/sup 2/ laser array was used to characterize the heat sink, and the value of 0.040 degrees C cm/sup 2//W was obtained for the thermal resistance per unit area. The extrapolated value for a 1-cm/sup 2/ heated area is 0.070 degrees C cm/sup 2//W. >

Microchannel heat sinks for two-dimensional high-power-density diode laser arrays

Heat dissipation design and analysis of high power LED array using the finite element method

We propose a diamond-shaped interrupted microgrooved cooling fin to decrease the junction temperature variation across the chip. The analytical result indicates that the junction temperature variation decreses to less than 25% compared with a conventional paralles-plate-shaped cooling fins. This cooling structure is sufficient to cool high-power-consumption silicon chips.

S. Saski

Papers

Cooling characteristics of diamond-shaped interrupted cooling fin for high-power LSI devices