Method of and system for determining an overlay or alignment error between a first and a second device layer of a multilayer semiconductor device

A method of determining an overlay or alignment error between a first device layer and a second device layer of a multilayer semiconductor device on a substrate using an atomic force microscopy system, wherein the atomic force microscopy system comprises a scan head including a probe, and the probe comprises a cantilever and a probe tip arranged on the cantilever, wherein the method comprises:

• moving the probe tip and the multilayer semiconductor device relative to each other in one or more directions parallel to a surface of the multilayer semiconductor device for performing a scanning of the surface with the probe tip, wherein the probe tip is intermittently or continuously in contact with the surface during said scanning;
• applying, during said scanning;
• and using a signal application actuator, an acoustic input signal to the substrate;
• monitoring a motion of the probe tip relative to the scan head with a probe tip position detector during said scanning for obtaining an output signal;
• and
• analyzing the output signal for generating a mapping of a one or more subsurface structures below the surface of the multilayer semiconductor device, the one or more subsurface structures being located in at least one of the first device layer or the second device layer, and
• determining the overlay or alignment error between the first device layer and the second device layer based on the mapping;
• wherein the signal application actuator includes a shear wave actuator, and
• wherein the applying an acoustic input signal comprises applying an acoustic input signal to the substrate using at least the shear wave actuator to provide a shear acoustic wave in the substrate, and
• wherein the output signal at least includes a sensor signal component indicative of a torsional deflection of the probe tip, and
• wherein the method includes obtaining said sensor signal component indicative of the torsional deflection of the probe tip.