Stepping level

Article summary

In integrated circuits, the stepping level or revision level is a version number that refers to the introduction or revision of one or more photolithographic photomasks within the set of photomasks that is used to pattern an integrated circuit. The term originated from the name of the equipment ("steppers") that exposes the photoresist to light. Integrated circuits have two primary classes of mask sets: firstly, "base" layers that are used to build the structures, such as transistors, that comprise circuit logic and, secondly, "metal" layers that connect the circuit logic. Typically, when an integrated circuit manufacturer such as Intel or AMD produces a new stepping (i.e. a revision to the masks), it is because it has found bugs in the logic, has made improvements to the design that permit faster processing, has found a way to increase yield or improve the "bin splits" (i.e. create faster transistors and thus faster CPUs), has improved maneuverability to more easily identify marginal circuits, or has reduced the circuit testing time, which can in turn reduce the cost of testing. Many integrated circuits allow interrogation to reveal information about their features, including stepping level. For example, executing CPUID instruction with the EAX register set to '1' on x86 CPUs will result in values being placed in other registers that show the CPU's stepping level.…

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