Development of a Slurry Employing a Unique Silica Abrasive for the CMP of Cu Damascene Structures

Abstract

We describe the development and examine the performance of a slurry containing an organic acid salt, a silica abrasive obtained from the hydrolysis of ethyl silicate ͑TEOS͒, and a passivating agent for the chemical mechanical planarization ͑CMP͒ of Cu damascene structures. The study is performed on full ͑200 mm͒ wafers coated with blanket Cu films to examine removal rates and uniformity and on partial wafers to investigate the CMP of Cu damascene structures. The silica slurry shows moderately high removal rates, good uniformity values, low defectivity, and excellent ability to remove the Ta liner. It is demonstrated that despite the fairly low Cu to SiO 2 selectivity values, a severe erosion of the SiO 2 does not occur. Because of the effective removal of the liner material, long overpolishing times become unnecessary, thus, spacer erosion is avoided. Corrosion induced defects are prevented by the addition of a passivating agent.

Localized corrosion effects and modifications of acidic and alkaline slurries on copper chemical mechanical polishing

“…A commonly used CMP utilizes abrasive particles that are suspended in colloidal slurry. Different additives or reagents can be combined with the slurry to provide high removal rates, good planarity and high selectivity [4][5][6], and to improve the dispersion of Applied Surface Science 210 (2003) 190-205 abrasive particles and rheological properties of the slurry [7,8]. As reported, copper CMP can be performed in either acidic or neutral or alkaline media with different function additives.…”

Scratch formation and its mechanism in chemical mechanical planarization (CMP)

“…Generally, a mixed abrasive slurry and various dispersants were used for the development of fine slurries [49,50]. Coutinho et al [48] synthesized composite particles containing ceria nanoparticles dispersed within cross-linked, polymeric microspheres formed by copolymerization of N-isopropylacrylamide (NIPAM) with 3-(trimethoxysilyl)propyl methacrylate (MPS), which can used as novel abrasive particles for CMP.…”

Novel ceria–polymer microcomposites for chemical mechanical polishing

“…Researchers in the recent past have studied mixed or modified abrasive particles in order to reduce defects during CMP [18][19][20]. These studies mostly use abrasives of different inorganic oxides and of different sizes or use micelles of surface active compounds.…”