The adhesion force between two interface layers in amorphous silicon solar (a-Si:H) module plays a crucial role in its carrier transport across the various interfaces. The quality of each interface layer depends on its mechanical properties. In other words, its mechanical property influences the performance of a-Si:H module. In this study, two mechanical properties of a PV module, which include interfacial adhesion and deformation across layers, were studied. The binding force between interfaces is susceptible to defects as a PV module begins to degrade. Therefore, the changes that occur in the adhesion force of a degraded a-Si:H is a proper tool for degradation analysis. Thus, this paper deals with the microstructure, defects, and mechanical properties of a-Si:H module. The aim of the study was to cross-examine which region of the degraded module was more prone to mechanical degradation. The degradation of adhesive strength results to mechanical defects, which can be observed as microstructural defects when mapped with Scanning Probe Microscope (SPM). The dearth of information on the correlation between these microstructural defects, and adhesive degradation is the motivations for this study. SPM was used to measure the adhesion force between interface layers, at a rate of 0.701Hz. In order to achieve uniformity in the results, each scanning was 512 lines for a retraced direction and the mapping was captured in an upward direction. The study shows that adhesion force exhibits a higher decay in the intrinsic layer interface p/i than in other regions. In addition, the sample from the affected region demonstrated a higher decrease in its adhesion force at the sample time has a higher deformation. Mechanical degradation at nanoscale level enhances interfacial delamination, which can potentially result to premature failure. Thus, an in-depth comprehension of adhesive degradation is essential in degradation analysis.