The stability of a novel weakly alkaline slurry of copper interconnection CMPfor GLSI

Abstract

Chemical mechanical polishing (CMP) is one of the important machining procedures of multilayered copper interconnection for GLSI, meanwhile polishing slurry is a critical factor for realizing the high polishing performance such as high planarization efficiency, low surface roughness. The effect of slurry components such as abrasive (colloidal silica), complexing agent (glycine), inhibitor (BTA) and oxidizing agent (H2O2) on the stability of the novel weakly alkaline slurry of copper interconnection CMP for GLSI was investigated in this paper. First, the synergistic and competitive relationship of them in a peroxide-based weakly alkaline slurry during the copper CMP process was studied and the stability mechanism was put forward. Then 1 wt% colloidal silica, 2.5 wt% glycine, 200 ppm BTA, 20 mL/L H2O2 had been selected as the appropriate concentration to prepare copper slurry, and using such slurry the copper blanket wafer was polished. From the variations of copper removal rate, root-mean square roughness (Sq) value with the setting time, it indicates that the working-life of the novel weakly alkaline slurry can reach more than 7 days, which satisfies the requirement of microelectronics further development.

Study on Effective Methods and Mechanism of Inhibiting Cobalt Removal Rate in Chemical Mechanical Polishing of GLSI Low-Tech Node Copper Film

“…When the distance between two silica sol particles is less than twice the thickness of the double electric layer, the slurry is prone to gel, delamination and deposition, which is not conducive to stable storage of the slurry for a long time. 15,16 In addition, according to Brownian motion theory, the particles are likely to collide with each other due to their irregular motion, which will result in agglomeration, residual and scratches on the surface of wafers. 17 Co hydroxides (Co(OH) 2 ) passivation layer on the surface, which may result in silica particles chemisorbed onto passivation layer by means of the oxygen bridging bonding.…”

Nanoscale-Precision Removal of Copper in Integrated Circuits Based on a Hybrid Process of Plasma Oxidation and Femtosecond Laser Ablation

“…Copper (Cu) is widely used in the fields of optics and micro-nano devices due to its low resistivity and superior resistance to electromigration, which can meet the requirements of high speed and low power consumption of the chip [1][2][3][4][5]. With the development of the integrated circuits (IC), nanometer surface roughness is required to adapt to the reduction in device size and the focal depth of lithography equipment [6][7][8][9][10]. Cu, as a common interconnection conductor in an IC, is required to have nanometer-level surface quality in IC applications.…”