Comparing the GDSII and AIF Layouts
Now that we have our two layouts (GDSII from package) and AIF (from the device description) accurately aligned, we should be able to see differences. However a visual inspection can be difficult.
a) some designs have several thousand bumps - it's easy to miss a difference in a field of so many bumps
b) it's also difficult to tell whether there are missing or extra bumps on the layer that is underneath.