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Abstract

An electrical test method and apparatus are disclosed. In the method one or more ring oscillators are formed in one or more layers prior to formation of a metal 1 layer of a semiconductor wafer. The one or more layers comprise the formulation of transistors and local interconnects. One or more test structures are formed in one or more interconnect layers at or after the metal 1 of the semiconductor wafer. Each test structure is coupled to a corresponding one or more ring oscillators. A voltage is applied to one or more non-precision contacts to cause the ring oscillators to oscillate. At-speed performance of one or more test structures is determined from one or more measured signals obtained from the test structures. The electrical test apparatus includes one or more ring oscillators formed in one or more layers prior to formation of a metal 1 comprising the formulation of transistors and local interconnects of a semiconductor wafer and one or more test structures formed in one or more interconnect layers at or after the metal 1 of the semiconductor wafer. Each test structure is coupled to one or more corresponding ring oscillators. A non-precision contact is coupled to the one or more ring oscillators for applying voltage to one or more non-precision contacts to cause the ring oscillators to oscillate.

First Claim