If you are sending and receiving silicon wafers for your processing and/or manufacturing requirements, you will no doubt have the pick of quality control or quality assurance procedures. The so-called pick and place procedures are meticulous to a fault.
In one case, located in Silicon Valley no less, no more than a dozen stages are in place to allow users to recycle and re-use their wafers. And of those stages, there must be at least four or five that act as QC checkpoints. Send your wafers to this facility and you will be in a strong position to manage your silicon wafer stock more cost effectively.
The proposed inventory to which you will be given access is computerized. Those that need it will always be given technical solutions or assistance. Typical wafer strip and reclaim procedures run chronologically as follows. There will be a goods receiving point. From there the process goes on to an incoming inspection, presorting, stripping and etching, a first quality control test, and polishing. And after that?
Still two more inspections to go. And after that? Yet another QC or QA test. How’s that for meticulous attention to detail. The income inspection counts all wafers received. During presorting, wafers are being sorted for film removal. And during the stripping and etching exercises, chemical processing will be removing all existing patterns and films. High grade equipment is being used to do the polishing work.
Wafers are polished with a prime test wafer surface. Surface specs are insured. But only a few microns will be removed through the use of low removal polishing technology. After the polishing has been completed, the wafers still need to be clean-spinned, rinsed and then dried. During the cleaning all remaining particles will be removed.