Techniques and mechanisms are provided for an improved built in self-test (BIST) mechanism for 3D assembly defect detection. According to an embodiment of the present disclosure, the described mechanisms and techniques can function to detect defects in interconnects which vertically connect different layers of a 3D device, as well as to detect defects on a 2D layer of a 3D integrated circuit. Additionally, according to an embodiment of the present disclosure, techniques and mechanisms are provided for determining not only the presence of a defect in a given set of interfaces of an integrated circuit, but the particular interface at which a defect may exist.