Wafer reclaim is typically defined as “a silicon wafer that has been processed, then stripped, sometimes polished, and then cleaned. Reclaimed wafers are becoming more and more popular because the quality is almost as good as a new wafer and the cost is significantly lower. Let’s take a look at the process that goes into making a GaAs reclaim wafers.
The sorting step is critical to prevent metallic contamination in the reclaim line. Sorting consists of inspecting the wafer including visual inspection, wafer type determination, and measurement of dopant and mechanical parameters.
The strip step will depend on the condition and previous processing of the incoming wafers. Typically, it’s performed in automated wet immersion batch tanks. Sulfuric acid and a hydrogen peroxide mixture are typically used during the stripping process.
Grinding may be required for thick wafers and to remove other films. Lapping and edge rounding are also often performed on the reclaim wafers.
The polishing step often uses a combination of chemical and mechanical polishing. The polishing step can leave residual slurry and unwanted particles and metallic contaminants on the wafer and these must be removed.
That’s where the cleaning process comes in. The cleaning step is performed in batch immersion tanks. Typically, the full cleaning process is performed sequentially in one cleaning bath. A surface tension dryer is used to dry the silicon wafer as the final step.
At Wafer World, we are proud to offer reclaimed wafers. Contact us today to learn more.