EVALUATION OF CU ADHESIVE ENERGY ON BARRIER METALS BY MEANS OF CONTACTANGLE MEASUREMENT

The adhesive energies at Cu/SiO2, Cu/TiN, and Cu/TiW interfaces were investigated by measuring the contact angles of Cu particles to the substrate. To form the Cu particles, thin Cu films deposited on each substrate were annealed at 500 degrees C for 50 h. The adhesive energies are determined to be 0.8, 1.8, and 2.2 N/m for the SiO2, TiN, and TiW, respectively. The Cu particle on TiW film shows the highest adhesion. When TiW is used as a barrier metal, fine Cu lines are fabricated by reactive ion etching without peeling. On the other hand, Cu lines on the TIN him are peeled during the etching. This is consistent to the evaluation result that TiW has higher adhesive energy than TiN. (C) 1995 American Institute of Physics.