All processes from etching through to sealing are performed in a class 1000 clean room with class 100 work stations and processes. This type of environment is considered essential for the final stages of production of high performance crystals as particle contamination can contribute greatly to DLD (Drive Level Dependency), poor phase noise, micro-jumps and aging. Process particle laser counters monitor the environment and critical stages and pieces of equipment, and liquid born particles are also monitored and controlled.