Undulation of sub-100nm porous dielectric structures: A mechanical analysis

Abstract

In microelectronics technologies, patterning of sub-100nm width ridges capped with a titanium nitride mask can lead to undulations of the ridges detrimental to performances. This phenomenon is observed with highly compressive residual stress into the mask (>2GPa), with dielectrics with low elastic properties (E<2Gpa) and with high dielectric ridge heights (>230nm). Experiments and simulations show that undulations can originate from buckling which allows the release of the strain energy initially stored in the mask. Simulations predict that the dielectric material undulations can become an issue for porous dielectrics integration in the next generations of integrated circuits (2016 and later).