A machine for electrochemical etch-stop

The configurations of electrochemical silicon etch-stop are discussed in this paper. An electrochemical etching machine (EEM) with software and hardware, which can control the etching process of silicon very well, is designed and fabricated based on the theory of electrochemical etching. Accurate etching temperature is got by modified integral algorithm of PID presented in temperature control in software. With an algorithm presented in control of etch-stop, the etch-stop point can be detected according to the characteristics of p-n junction current-time in electrochemical etching. The machine with hardware including S/H, controller and actuator can adapt to all wet etching configurations such as poly-electrode electrochemical etch-stop.