Local stress measurement on metal lines and dielectrics of BEoL pattern by stress relief technique

The paper presents a new measurement method for residual stresses introduced by manufacturing in BEoL structures. Material removal by FIB ion milling is used to release elastically frozen stresses. Normal stress components are calculated from local stress relaxation nearby milled trenches. A validation of the new technique is accomplished by additional bow measurements on defined layers on substrate. Spatially resolved determination of stress values in metal lines and the dielectrics in between demonstrates the capability of the tool for future applications.