Chipworks has reversed engineered the Apple A5 processor used in the iPad2.
They decapsulated the A5 a couple of days ago, but as you could see in those early pictures, you can’t tell much of a chip’s layout from the top metal – it’s all power and ground buses. So they had to de-layer the chip down to a level to see the block layout of the chip; not an easy thing when there’s nine layers of metal! In fact, these days it’s easier to go in from the back and remove the substrate silicon, and look at the gate level from below. Then they identify the circuit blocks that make up the full device.
For the A5, a dual ARM core processor:
Apple A5 Polysilicon Die Photo with Annotations
The ARM cores are in the right half of the die, with ~4.5 Mb of cache memory each. You can also see the USB interface at the top, and the DDR SDRAM interfaces at the bottom right, for the memory in the top part of the package-on-package. Other I/O blocks are strewn around the edge of the die.
It seems likely that Apple will actually be shipping TSMC-made parts later this year, since Samsung is a competitor with its Galaxy tablet series, but the current devices are made by Samsung, as shown by a cross section of the chip:
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