Investigatory nanoscale thickness of the chemical reaction layer of sapphire substrate for the various dipping temperatures of slurry suitable in CMP

Abstract

An innovative theoretical model and experimental method were proposed to calculate nanoscale thickness of the chemical reaction layer of sapphire substrates and analyzed the various slurry dipping temperatures affecting the thickness of the chemical reaction layer. The slurry used in this study was suitable to use in the CMP experiment of polishing the sapphire substrate. A small down force was applied to cut sapphire substrates dipped in slurry for varying dipping temperatures to obtain the specific down force energy (SDFE) values corresponding to the thickness of chemical reaction layer. Nanocutting was performed with a cutting depth interval of approximately 0.05 nm to obtain the SDFE values. Thus, changes in SDFE values is a critical target. The measured SDFE values were then used to develop a theoretical method for calculating the thickness of the chemical reaction layer of sapphire substrate according to the various dipping temperatures of dipping slurry. AFM nanoscale cutting with a cutting depth interval of approximately 0.01 nm was conducted and found the changes in the SDFE values, which were used to measure the thickness of the chemical reaction layer for each slurry dipping temperatures. The experimental results verify that the proposed theoretical method is feasible. Finally, it conducted a regression analysis for the thickness of the chemical reaction layer and various dipping temperatures. The results indicate that the slurry dipping temperatures increased, the chemical reaction layer thickened; and the increase of the chemical reaction layer thickness was approximately linear.