Method of determining stressors applied to a substrate

A non-transitory computer-readable medium comprising stored program instructions configured, when run on a suitable apparatus, to cause the apparatus to at least:

• obtain substrate position data describing positional information of structures on a substrate in a substrate plane;
• obtain substrate shape data describing a shape of the substrate;
• determine a first warp value from the substrate position data, the first warp value describing a warpage of the substrate;
• determine a second warp value from the substrate shape data, the second warp value describing the warpage of the substrate;
• and
• determine a presence of a stressor on a back-side of the substrate based on the first warp value and second warp value.