This fingerprint (aka Physically Unclonable Function, or PUF) is a byproduct of tiny errors in thefabricationprocess -- something chip makers usually try to minimize.
Again, the beauty of the design and the ingenuity of the manufacturing process take our attention away from the human element that goes into their fabrication.
The Exynos 4 chip found in Samsung's flagship Galaxy S3 handset and Apple's A5X used in the iPad 3 both use transistors using a 32 nanometre fabricationprocess.