Modifying residual stress and stress gradient in LPCVD Si3N4 film with ion implantation

The paper presents a method for modifying residual stress in LPCVD Si₃N₄ films. Utilizing ion implantation technology, the residual stress and stress gradient in Si₃N₄ film have been successfully modified with a wide adjustable range. An analytical model has been developed to describe the modification. The dosage and energy of ion implantation can be controlled accurately, and therefore the presented method can modify stress level precisely. With this method, the mean residual stress in a Si₃N₄ film was adjusted from 1.2 GPa tensile to -0.1 GPa compressive continuously. Moreover, cantilever curling caused by stress gradient was reduced efficiently.