Abstract

 The rapid decrease in interconnect Critical Dimensions (CDs) within logic devices and growth in the contact height of 3D memory devices have led to increased contact/via plugs resistance. In this study, we introduce an approach to reduce the resistance of the contact/via plugs by engineering the grain size of the plugs using Nanosecond Green Laser Annealing (NGLA) with a low energy fluence (=0.1 J/cm2). Because of the proximity between adjacent W plugs, diffraction of the laser light can occur which will help the laser energy to be absorbed by the sidewall of the W plugs. In addition, the difference in reflectivity between the plug region and W interconnect lines can cause grain size enlargement to selectively occur in the plug region. The NGLA process increased grain size in the plugs up to 79.9 %, resulting as much as a 26 % reduction in tungsten plug resistance. The standard deviation of the plug resistance was also improved from 14.6 % to 7.9 % after the NGLA process.