Although silicon wafers have been manufactured for more than 50 years now, the process still isn’t perfect. Every batch of wafers created has its bad wafers.The process has advanced to the point that volume and overall yield has increased dramatically, but it is not 100 percent.So when it comes time for you to be in the market for silicon wafers, there are some key elements you need to look out for when buying, to make sure you don’t get a bad wafer or a bad batch. You are in control, as the customer, and you should demand satisfactory wafers.
Rounding: While silicon wafers are manufactured from cylindrical single-crystal (monocrystalline) shapes – and thus, are circular in nature – there is a process which finished wafers go through that is called edging or rounding. This process, when done correctly, helps the wafer maintain its pliability and strength. If it is not done well, then the wafer is liable to crack or split. There are some companies that report huge increases in yield on wafers when the rounding is done to very precise standards. Make sure to check the roundness of the wafer and be aware of any imperfections.
Etching: As wafers are made, there will be etching done to put the circuits on the chips as part of the process of preparing the chips for use in computer devices. However, the etching process is one at a micro and nano level that is nearly impossible to have a clean wafer. What you need to look for here is etching that looks abnormally high and especially those outside of the chips near the edges of the wafers. Scratching may be inevitable, but if the scratches seem excessive, that could compromise the wafer’s strength and thus subject it to damage, which may then compromise the chips themselves.
Charge: We of course put our wafers through rigorous quality control, so we feel like you can trust that our shipment will be of only top quality wafers. Another key feature to look for in wafers is that they are the right charge for you to use.Yes, we said charge. You can use a wafer probe to check a silicon wafer. Generally it should be neutral, but a bad wafer will have more negative charge than a good wafer. If there is too much negative charge, that usually means that some electrons got loose and there are gaps in the silicon bonds, which may affect the performance of the circuitry of the chips that create the electric current (the flow of negatively-charged electrons).In all of these cases, we are happy to work with you to ensure that you receive exactly the right wafers for your needs that meet the most stringent standards.
