Photolithography Photolithography is performed using one of three contact aligners. Two of the aligners are traditional mask aligners offering the capability of printing lines of about 1 micron or more. The third aligner has an infrared camera that allows alignment of the front side of the wafer to patterns on the back side of the silicon. This is useful for sensor and for micromachining common in silicon technology. Both wet and dry etching are available.
Wet etching is carried out using a variety of etches matched to the material being etched.
Dry etches are done in a Techniques plasma etcher. Silicon, silicon dioxide and silicon nitride are among the materials commonly etched using plasma etching. Diffusion Diffusions are currently limited to phosphorus. A liquid source of phosphorus is used due to the increased safety of liquid sources compared to gas sources. High quality phosphorus diffusions can be achieved over a wide range of concentrations and depths.