New processing techniques: sweeping of quartz wafers and a practical method for processing quartz resonators under controlled conditions

Electrodiffusion of 'sweeping' has been used to remove impurities from quartz material. Traditionally, quartz is swept in the bar form prior to being cut into wafers. It is argued that it would be advantageous to place the sweeping operation later into the process, i.e., experience as much of the blank processing yield loss as possible with unswept quartz, and only sweep those that have successfully completed the blank processes. A system has been developed to greatly improve the conditions under which resonators are processed, without totally retooling the manufacturing line. The system utilizes a transportable chamber within which partially completed resonator assemblies are kept. The chamber allows access to the crystals in a clean, dry, gas environment. The temperature of the chamber can be raised to more than 300 degrees C to facilitate the elevated temperature steps in the process, i.e., conductive cement curing, preplating bake, etc.<>