Reusing old wafers isn’t a good idea, it could lead to high variances in temperature control and other problems down the line with continued use. When wafers heat up they expand, and contract when they cool down. This constant contraction/expansion cycle leads to wear and tear with repeated uses. If you replace wafers often and want to save some of the costs, wafer reclaiming services may be right for you.
The wafer reclamation process can be a task to accomplish on your own, but reclamation services take the work from your hands and deliver quality inspected reclaimed wafers at a reasonable price. These services will pick up the product from their customers, count the product, and inspect its original condition before sending the wafers to be presorted by thickness. The presorting process employs stripping schedules manufactured for wafers with multiple layers, so variant sizes are no problem to handle.
The service will then strip away any preexisting films and patterns with a specially-designed chemical process before polishing them with a primed and tested wafer surface to ensure all surface specs, with barely any microns removed by low removal polishing techniques. They are then cleaned, rinsed, and dried by using a SC1 process or a SC2 process to remove all particles.
Once the cleaning process is done, reclaimed wafers are first visually inspected and then put through a final inspection by a KLA-Tencor Surfscan 6400 that ensure the particle count specification. Then the product is once again sorted, a report of quality is done with specified readouts. Wafers are then inspected once more, vacuum-packed, and delivered quite often on the same business day.
Next time you’re thinking of throwing away all those used wafers, save some money and send them to a reclamation service that will inspect the quality, trim, clean, and restore them to their original quality.