Methods and Apparatus for Testing Pads on Wafers

摘要

Methods and apparatuses for sharing test pads among function blocks under test within multiple layers of a die are disclosed. A semiconductor wafer comprises a first die and a second die separated by a scribe line. A first pad, a second pad, and a third pad are located in the scribe line. The test pads may be located within a die as well. The first pad and the second pad are used to test a first function block within a first layer, and the first pad and the third pad are used to test a second function block within a second layer of the first die. The shared first test pad are used to test multiple function blocks contained in different layers of the die. Therefore fewer test pads are needed which leads to reduced area for scribe lines in a wafer.