Electronic – How are microchips designed


I was just wondering how the microchips are actually designed. I was watching the Apple presentation on the A7 chip and they were saying there is over a billion transistors on the chip. To my mind, it would take a team of thousands to design that, and yet there seems to be a newer, faster, bigger chip every year.

Are computer programs or people designing the chips?

Best Answer

Both. And there's quite frequently a team of hundreds involved; the latest Intel flagship processor will probably have had over a thousand people involved in design decisions somewhere (especially if you count technical input from the foundry, which is vital if you're using a new manufacturing process).

Generally the process involves:

  • high level architecture design, by humans
  • implementing the design in Verilog and/or VHDL, by humans
  • translating that into logic gates, by software
  • placing the gates and routing wires between them (software with constraints and guidance by humans)
  • analyse the result (software) and review key areas for improvement (by humans)
  • translate gates to images for photomasks (represented in the "GDS II" file format)
  • generate test data (software-assisted humans)
  • manufacturing and test process (mostly automated)

Edit: there are also lots of things which up the transistor count without having to design them all individually; SRAM, for example, is a large grid of repeating elements. The A7 will have a substantial fraction, maybe a majority, of its transistors devoted to L1 and L2 cache.