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  Table Of Contents:

   Wintron's Worldwide Manufacturing Facilities:

       
    Wintron's Willington manufacturing facility in U.S.A
    Wintron's Frankfurt manufacturing facility in Germany
   
    Wintron's Toronto manufacturing facility in Canada
  
  The Flow Chart of Crystal Production Process:

      
Wintron's crystal oscillator products go through the entire production process with the advanced and innovative manufacturing and testing equipment.

Sawing
Slicing quartz wafers is basically the first step in the production of crystal resonators. During slicing, the highly accurate slurry saw essentially abrades through several bars of quartz material at one time. The quartz bars have been oriented so that the individual slices will have the required  frequency versus temperature characteristics. Generally, up to six bars can be sliced at one time yielding anywhere from 200 to 400 individual wafers. A typical saw run will take about 6 to 8 hours to complete.
Sawing /Slicing Machine

Lapping

'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 .

Four-way lapping machine

Dimensioning The Blank

The blank dimension is critical to the crystal design. Depending on the crystal package the blank is rounded or cut into a rectangular shape.

Dimensioning the blank to tight tolerances with a fine surface finish is also important with respect to frequency temperature performance and aging.

Seed removal and wafer rounding machines

X-Ray
The quartz wafers or blanks are X-rayed to measure the angle with respect to the reference lattice plane in terms of degrees, minutes and seconds.
EFG X-ray machine

Cleaning/Etching

The quartz blanks are etched in an acidic solution to improve the surface finish and reduce the spread in frequency of the production batch.

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 equipment, and liquid born particles are also monitored and controlled.

Etching station

Thin Film Deposition

A high vacuum thin film deposition machine evaporates a metal onto the surface of each blank to form an electrode pattern.

This base plating process is considered to be most critical in achieving well-behaved low aging crystals.

Thin film desposion

Auto Mounting and Gluing

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.

Auto mounting and gluing

Precise Plating
The frequency of each quartz crystal is measured while a metal is evaporated onto one side of an exposed electrode until the target frequency is reached to within ±1ppm.
Precise plating equipment

Calibration

Calibration is the final plating step for the resonator. In many aspects, the process is similar to the deposition of the electrode except that far less metal is used. The purpose of calibration is to finely adjust the frequency of the resonator to a specified operating point.Generally, the frequencies of quartz resonators are calibrated to less than ±1ppm of their target frequencies.

Interestingly, the whole process of plating the electrode and calibrating are reverse as to their effects on the quartz resonator with respect to the grinding and lapping operations. Consequently, the processes of quartz removal and metal deposition are used in conjunction to iteratively create the desired operating frequency.

Calibration Equipment

Sealing

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.

Resistance weld

Temperature and Aging Testing

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.

 

Testing Process

Temperature Test
The crystals are 100% tested in the temperature chambers for frequency characteristics over the intended temperature range.

Temperature test chambers

Initial and Final Crystal Test

The crystals are tested for their motional parameters and sorted into frequency groups.

After aging at an elevated temperature for a period of time the motional parameters are tested again ensuring the parameters are maintained to the required process specifications. This is an essential SPC (Statistical Process Control) point to highlight any process problems.

 

Crystal testing apparatus

PCB Assembly, Crystal Matching and TCXO Assembly

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.

Surface mount machine

Final QC And Packaging
Any leg-forming, jacketing and marking of the crystals is inspected. The crystals are then packed and released by our O.Q.C. department.

Quality control station

 
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