Correlation of Surface and Film Chemistry with Mechanical Properties in Interconnects

As the industry moves towards using low k dielectrics in advanced interconnects, interfacial adhesion and film mechanical properties play increasingly important roles in yield and reliability. Improving these mechanical properties requires a better understanding of the surface, interface and film chemistry. Time‐of‐Flight Secondary Ion Mass Spectrometry (TOF‐SIMS) was used to examine the surface molecular structure of organosilicate and organic polymer based low k interlayer dielectrics (ILDs). Strong correlations were established between surface group functionality, reactivity of the TiN precursors with the ILDs during Atomic Layer Deposition (ALD), and adhesion between the copper barrier and the ILDs. Hydrogen plasma treatment significantly changed the surface chemical structure of the polymer ILD through hydrogenation. Correspondingly, degradation of barrier/polymer adhesion and thermal stability was observed. For the organosilicate ILD, the modulation of film chemistry, primarily the siloxane structur...