Measurements of surface deformations and strains using an AFM moire method

摘要

An AFM (atomic force microscope) moire method has been developed to measure surface deformations and strains. The scanning lines in the AFM monitor are used as the reference grating. The reference grating interferes with the specimen grating and forms a moire pattern on the monitor. The condition of forming scanning moire with an AFM is described. The deformation measurement principle using AFM moire is discussed in detail. The AFM moire method was used to measure the thermal deformations in QFP (quad flat pack) and BGA (ball grid array) packages. The experiment results verify the feasibility of the AFM moire method and show its ability to measure the in-plane deformations and strains.