'Four way' lapping machines grind the wafer surfaces using abrasives to a targeted thickness while maintaining flatness in a three stage process: first in wafer form, then diced form, and finally, after rounding.

With AT-cut quartz blanks, the wafer thickness determines the frequency. An accuracy of 0.1mm or less is required .

Mounting and gluing is performed by purpose built robots designed to perform their function with low contamination and stress.

The quartz blank is mounted on a supporting fixture with a conductive glue making electrical contact to the electrodes on each side of the blank.

The inside of a holder is evacuated and filled with the inert Nitrogen gas to protect crystal elements mechanically and prevent electrodes or other parts from being oxidised or influenced by ambient temperatures. Sealing methods of resistance or seam welds are used depending on the package.

Sensors monitor the process environment.

The crystals are then fine and gross leak tested before parameter testing and aging.

After seal,the resonators are placed into environmental screening to verify their electrical performance and frequency characteristics over the required operating temperature range. Quartz resonators are shown above loaded into one of Wintron’s many ATE systems. In addition to testing for temperature performance, precision resonators are subjected to accelerated life testing which includes high temperature bakes at over 200 degrees Centigrade. This accelerated life testing is one of the methods used to confirm the expected yearly rate of frequency drift most often referred to as aging.

The PCB panels go through Solder Paste Screening, Component Pick and Place and IR-reflow Production Line.

Crystals are matched to assembled PCB. This also allows for a narrow trimming range making it easier to tune the oscillators on frequency.