The Effect of Etch Depth on Etch Rate and Undercut During the Double-sided Etching Process

Many factors affect the process of double-sided etching. Two of the major factors are the diffusion layer (puddle) and the material thickness. They have an effect on the etch rate, the undercut, and the finished product. For the sake of this discussion, material up to 5-mil in thickness will be considered thin material and above 5-mil will be considered thick material.