Spin Defect on the edge of the semiconductor wafer is a coater issue that effects the wafer edge. A spin defect appearing on the edge of the semiconductor wafer is typically due to lack of resist volume to sufficiently coat the entire wafer. This type of defect can also be caused by other process problems including topography process problems.
Here is another good example of a spin defect appearing on the edge of the wafer.
Another example of a spin defect on the edge of a semiconductor wafer. Note that in some instances, there may be only a single spin defect on a wafer.