Effect of Conditioner’s Tip on Pad Restoration during CMP Conditioning Tae-Hyeok Kang

Abstract

In the fabrication of high-performance CMOS (Complementary Metal-Oxide Semiconductor) devices, components are increasingly becoming smaller and advancing toward a 3D stacked structure. Due to these requirements, Chemical Mechanical Planarization (CMP) has become a core element in semiconductor processes. For optimal performance in CMP, the roles of consumables such as slurry, pad, and conditioner are crucial, and these components are intricately interconnected. However, there are few studies on conditioners, which fall under the category of consumables. In this study, evaluates the pad restoration by a diamond tip of a ‘standard conditioner’ and a ‘ceramic-based CVD (chemical vapor deposition) conditioner manufacturing by the cutting process’. Generally, the conditioner with a CVD diamond coating is recognized for exhibiting superior chemical resistance and pad surface profile compared to the conventional standard conditioner. Consequently, the efficiency of pad restoration for the conditioner was compared and evaluated based on the concentrations of H2O2 and glycine, additives in silica slurry used for metal CMP. Field emission scanning electron microscopy (FE-SEM) and a 3D profiler were utilized to evaluate pore restoration on the pad and the wear rate of the conditioner after conditioning. To evaluate the pad restoration performance based on the slurry composition of each conditioner, a 10-minute CMP was performed on dummy wafers, followed by conditioning. Subsequently, CMP was performed under various slurry conditions to measure the wafer's removal rate and roughness. The wafer thickness was measured using a 4-point probe, and roughness was measured using atomic force microscopy (AFM).