At this point the processors are complete and all that is left is to test, package and speed bin the chips. Testing is conducted at a basic level while the dies are still in wafer form, with a simple test algorithm given to the chip. Any chips outputting the wrong answer are marked and discarded once the wafer has been delicately cut into individual CPU dies.
Left: We're almost sure they don't use circular saws for this... Right: The completed and cut die - in this case a Clarkfield CPU and GPU destined for a Core i5
Individual dies are then ready to be packaged into what many people would recognize as a CPU. The die sits on a substrate (or PCB) in a socket that connects it to the pins or contact points of the packaging. The chip is then glued in place, and a heat spreader placed on top of it to help effectively conduct heat away from the chip .
Left: A delicate socket on the substrate of the CPU package connects the die to the pins or pads on the underside. Right: Speed binning - the X-Factor of the CPU world.
Once the chips have been packaged they go through a class testing or ‘binning’ process whereby their thermal and frequency characteristics will be analysed. Think of it as an audition process, with each chip hoping to be capable of getting a role at the top end of the range, running at the highest frequencies. Unfortunately, due to tiny variances in the production process, some chips may not run as well and will have to be content with being binned as lower range chips - at least they avoid a cringey interview with Ant and Dec.
Once the chips are binned and packaged they can be send out to system builders in trays of 1,000, or to online retailers in their more flashy retail packaging, ready to be bought and put through their paces by the public.
Left: CPUs get sent to system builders in trays. Right: Consumers get the fancy packaging.
The lucky CPUs may end up spending their life rendering the beautiful landscapes of the latest games and videos, or even help create the next CGI Blockbuster. However, spare a thought for the poor, tortured chips that spend their life sweating and straining in one of James’s myriad of folding rigs.