Key Functions

• Edge Temperature Uniformity
  The guard ring reduces radiative heat loss at the wafer perimeter. By mimicking the thermal mass and emissivity of the wafer, it helps maintain a more uniform temperature profile across the wafer surface.
• Slip Reduction
  “Slip” refers to dislocation defects caused by thermal stress, visible by so-called “slip lines”. By minimizing edge cooling and steep temperature gradients, the guard ring significantly reduces the risk of slip formation during rapid heating and cooling cycles.
• Process Repeatability
  A stable thermal boundary condition improves run‑to‑run consistency, especially in high‑temperature steps such as annealing, oxidation, or dopant activation.