Wafer backgrinding is an essential semiconductor device fabrication step that aims to reduce wafer thickness to generate ultra-flat wafers. Wafers are generally about 750 μm thick to guarantee mechanical stability and to prevent warping during high-temperature processing. But several methods can be done to safely thin wafers even more. Unfortunately, despite taking precautions, the backgrindig process can cause stress and damage to the wafers. So here’s everything you need to know about reducing stress and damage in a wafer after the backgrinding process.
The stresses enforced during encapsulation in the backgriding step can crack the wafers and cause other stress-related deficiency. Unfortunately, this is inevitable. Backgrinding can leave flaws on the wafer’s surface, which affects the wafer’s performance. Given the processes each wafer must go through to complete wafer fabrication, these damages can further spread and worsen into active regions. That’s why it’s important to get rid of cracks and other damages to guarantee highly efficient and reliable wafers.
Backgriding is a complex process, but some parameters can be taken to optimize this process and to reduce damage. After carefully grinding wafers to achieve ultra flat wafers, damages will still be present.The damage can penetrate two layers: the surface of the wafer which can be full of micro-cracks, causing warpage and stress in the wafer; and the second layer, which may contain crystal dislocations that could affect the electrical properties of the wafer. Wafer etching and polishing can help get rid of these damages, and probe testing is done to guarantee that the parts damaged during the backgrinding process are not transferred to bonding.
Ultra flat wafers can be used in applications that have specific wafer thinness requirements. At Wafer World, we offer wafers that meet your business or production needs. Order yours online today or contact us to request a quote!