Fabrication of very smooth walls and bottoms of silicon microchannels for heat dissipation of semiconductor devices
In microchannel fabrication, smooth walls and bottom formation has been an uphill task during micromachining of (110) silicon due to its orientation-dependent chemical etching. A new method to fabricate deep microchannels on (110)-oriented silicon wafers for cooling excessive-heat dissipating semiconductor devices has been developed. Potassium hydroxide, water and isopropanol-based etchants have been used to etch silicon anisotropically for fabricating deep, narrow and smooth-walled microchannels. For etching U-grooved microchannels, (110)-oriented and 500550?m-thick monitor grade silicon wafers are used. Proper orientation of the pattern to be etched is aligned with reference to the standard flat provided in the wafer. A new method replacing conventional additional plane-finding etching procedure has been developed, where proper orientation is experimentally determined on the given wafer for pattern delineation. Very smooth walls and bottom of about 400?m deep silicon microchannels have been obtained after controlling the etchant composition, temperature and orientation of the masking pattern. In this paper process details are presented along with experimental results. This process has further been used for separating the silicon microchannel chips.
heat dissipation semiconductor devices microchannel fabrication