Formation of silicon reentrant cavity heat sinks using anisotropic etching and direct wafer bonding

Author

Goyal, Ajay ; Jaeger, Richard C. ; Bhavnani, Sushil H. ; Ellis, Charles D. ; Phadke, Narendra K. ; Azimi-Rashti, Mehdi ; Goodling, John S.

Author_Institution

Alabama Microelectron. Sci. & Technol. Center, Auburn Univ., AL, USA

Volume

14

Issue

1

fYear

1993

Firstpage

29

Lastpage

32

Abstract

A novel silicon reentrant cavity heat sink for enhanced liquid cooling of silicon multichip substances has been fabricated using a two-step anisotropic etching process followed by silicon direct wafer bonding. Cavity mouth openings ranging from 8 to 500 mu m have been batch fabricated with the two-step process. The reentrant cavities suppress the temperature overshoot normally associated with the transition between the free convection and nucleate boiling regimes of liquid immersion cooling. Nucleate boiling has been observed to occur at heater fluxes below 2 W/cm/sup 2/ for both increasing and decreasing heat flux conditions. Specific thermal contact resistances (heater fluid) of less than 0.6 K-cm/sup 2//W have been measured in Freon-22, R-113, and FC-72.<>

Keywords

boiling; cooling; etching; heat sinks; multichip modules; silicon; wafer bonding; 8 to 500 micron; FC-72; Freon-22; R-113; Si multichip substrates; Si reentrant cavity heat sinks; anisotropic etching; cavity heat sinks formation; cavity mouth openings; direct wafer bonding; enhanced liquid cooling; heater fluxes; liquid immersion cooling; nucleate boiling regimes; temperature overshoot suppression; thermal contact resistances; two-step process; Anisotropic magnetoresistance; Etching; Heat sinks; Immersion cooling; Liquid cooling; Mouth; Silicon; Temperature; Thermal resistance; Wafer bonding;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/55.215090

Filename

215090