A Study of the Stress Induced during Manufacturing Processes of Chip Inductors

Ni-Cu-Zn ferrite components are very sensitive to stress and this can cause unstable permeability. This work focuses on the source of stress, and the interaction between the residual stress after sintering and the further stresses contributed by subsequent manufacturing processes of multilayer chip inductors. The results show that the sources of stress include cofiring of ferrite and silver coils, and the operations involved in the manufacturing processes. The results also show that the stresses pass through the interfaces between materials to the body of component and that the stresses induced in the subsequent manufacturing processes would accumulate or counteract with the residual stress in the component, although the stress can also be released by changing the connection status of these interfaces. The results also show that the compressive and tensile stresses cause different levels of inductance shift.