Ta-Si-N BARRIERS AGAINST Cu DIFFUSION

초록

The barrier properties of Ta-Si-N was investigated using X-ray diffraction and AES depth profiling particularly focussing the effect of the N2/Ar gas flow ratio of the reactive sputter deposition process on the barrier properties of Ta-Si-N. Ta-Si-N fails at 900℃ when it is in contact with Cu, while Ta and TaN fail at 600 and 650℃, respectively, The optimum N2/Ar flow ratio in the sputter deposition of Ta-Si-N which offers the best barrier property is 15%. The Ta-Si-N barrier fails by migration of Cu through the Ta-Si-N layer to the Ta-Si-N/Si interface and reaction of Cu with Si to form copper silicides. The crystallization temperature of Ta-Si-N in the Cu/Ta-Si-N/Si sample is higher than 900℃. Therefore, the failure of Ta-Si-N at 900℃ is not directly related to the crystallization of Ta-Si-N.