Finite element simulation of isothermal regions in serpentine shaped PCB electrodes of a micro-PCR device

Polymerase chain reaction (PCR) is a method or device which is widely used in biology labs. Its main job is copying DNA segments. Micro-PCR is the term referring to the small-scale version of this device. It has several advantages including the minute reagent consumption and faster response times. One of the challenges in micro-PCR technology is creating uniform-temperature regions. Thin film heaters have been used in literature to create the needed temperature zones. In this work, printed circuit board (PCB) technology has been used to create meander-shaped micro heaters on FR-4 substrate. Two separate temperature zones have been designed on the substrate. In order to improve temperature uniformity in these areas, a uniform copper layer has been designed on the back of the substrate. Thanks to the double-sided PCB technology, having a uniform copper layer on the back of the substrate is trivial. To study the effect of the copper layer on temperature uniformity, a steady state thermal model has been developed using Ansys®Workbench. Based on the simulation results, the created model can successfully predict temperature distribution in these heat generation areas. Besides, it is shown that the copper layer will lead to more uniformity in temperature distribution.