Etching technology uses the chemical reaction between the specific solution and the thin film to remove the film which is not covered by the photoresist and achieve the purpose of etching. This etching method is also called the so-called wet etching. Because the wet etching is removed to film by chemical reactions, and chemical reactions themselves have no direction, so as to the wet etching process, the linewidth in general in this way is not enough to define 3 microns or less, but for more than 3 micron wet etching linewidth definition is still a choice of using the technology.


Low cost, high reliability, high capacity and excellent etching selection ratio. But compared with dry etching, but cannot define fine linewidth, wet etching is still has the following disadvantages:
1) takes the reaction solution and the deionized water cost is high;
2) the security problems encountered in the chemical processing personnel;
3) photoresist adhesion problems;
4) gas bubble formation and chemical etching the liquid cannot contact the surface of the wafer incomplete and non-uniform etching;
5) and potentially explosive gas.