Wafer acceptance testing method and structure of a test key used in the method

摘要

A wafer acceptance testing (WAT) method with a test key is provided. The test key structure includes a testing structure on a substrate. An inter-layer-dielectric layer covers over the substrate to isolate the testing structure. A grounded metal layer is located on the inter-layer dielectric layer. An interconnecting structure is located on the grounded metal layer. A conductive pad layer and a passivation layer are sequentially located on the interconnecting structure. The testing structure is electrically coupled to the interconnecting structure. The interconnecting structure is also electrically coupled to the conductive pad layer. The grounded metal layer is grounded without any further coupling such that the grounded metal layer is not coupled to the testing structure and the interconnecting structure.