4 ecen 475 p substrate sio2 photoresist

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Unformatted text preview: 0000000000000000 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 Expose photoresist through n-well mask Strip off exposed photoresist Lithography Strip Photoresist Strip off remaining photoresist Use mixture of acids called piranah etch Necessary so resist doesn’t melt in next step SiO2 000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 p substrate ECEN 475 71.4 n-well n-well is formed with diffusion or ion implantation Diffusion Place wafer in furnace with arsenic gas Heat until As atoms diffuse into exposed Si Ion Implanatation Blast wafer with beam of As ions Ions blocked by SiO2, only enter exposed Si SiO2 0000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 n well 81.4 ECEN 475 9 Strip Oxide Strip off the remaining oxide using HF Back to bare wafer with n-well Subsequent steps involve simi...
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This document was uploaded on 03/02/2014.

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