Stepping level

The term stepping level or revision level in the context of CPU architecture or integrated circuit is a version number.

Stepping level refers to the introduction or revision of the lithographic photomask or masks within the set of plates that generate the pattern that produces 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, base layers that are used to build the structures that make up the logic such as transistors, and metal layers that connect the logic together.

Typically, when an integrated circuit manufacturer such as Intel or AMD invests money to do a stepping (i.e. a revision to the masks), they have found bugs in the logic, have made improvements to the design that allow for faster processing, have found a way to increase yield or improve the "bin splits" (i.e. create faster transistors and hence faster CPUs), improve maneuverability to more easily identify marginal circuits, or reduce test time which can reduce the cost of testing the part.