3D simulation and analytical model of chemical heating during silicon wet etching in microchannels

International Conference on Computer Simulation in Physics and Beyond 2015

物理学;计算机科学

Konakov, S.A.^1 ; Krzhizhanovskaya, V.V.^1,2,3

Peter the Great St. Petersburg Polytechnic University, St. Petersburg

195251, Russia^1

University of Amsterdam, Amsterdam

1098 XH, Netherlands^2

ITMO University, St. Petersburg

197101, Russia^3

关键词: Complex microstructures;    Estimation of process;    Heat and mass transfer;    Heat transfer equations;    Potassium hydroxide solution;    Silicon wet etching;    Straight microchannels;    Viscous incompressible fluids;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/681/1/012035/pdf
DOI  :  10.1088/1742-6596/681/1/012035

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

We investigate chemical heating of a Silicon-on-Glass (SOG) chip during a highly exothermic reaction of silicon etching in potassium hydroxide (KOH) solution in a microchannel of 100-micron width inside a 1x1 cm SOG chip. Two modeling approaches have been developed, implemented and compared. (1) A detailed 3D model is based on unsteady Navier-Stokes equations, heat and mass transfer equations of a laminar flow of viscous incompressible fluid in microchannel, coupled to the heat transfer equation in the solid chip. 3D simulation results predicted temperature distributions for different KOH flow rates and silicon etching areas. Microchannels of a small diameter do not heat the chip due to the insufficient chemical heating of the cold fluid, whereas large-area etching (large channel diameter and/or length) leads to local overheating that may have negative effects on the device performance and durability. (2) A simplified analytical model solves a thermal balance equation describing the heating by chemical reactions inside the microchannel and energy loss by free convection of air around the chip. Analytical results compare well with the 3D simulations of a single straight microchannel, therefore the analytical model is suitable for quick estimation of process parameters. For complex microstructures, this simplified approach may be used as the first approximation.