Effects of Changes in Gas Type and Partial Pressure on Chemical Mechanical Polishing Property of Si Substrate

Abstract

As a critical link of efficient and high-quality semiconductor substrate chemical mechanical polishing process, this paper focuses on the effects of the changes of the atmosphere to be processed on the CMP property of Si substrate. The experiment results showed that O2 existing in the processing atmosphere played an active role in facilitating material removal, and when the partial pressure of O2 in the processing atmosphere increased to 500kPa, the Si MRR of CMP reached 905nm/min. The Si material surface dissolutions in different atmospheres were analyzed respectively using SEM, EDS and light interference microscope. It was found that when O2 was sufficient, an extremely thin and tight oxide film was formed on the Si substrate surface, which prevented the furtherance of oxidation reaction, and compared with the Si-Si bonds, the Si-O bonds generated during this process were more inclined to undergo hydrolysis reaction; on the other hand, the O2 atmosphere caused the polishing pad, polishing particles and Si substrate to contact closely, increasing the mechanical friction and thus significantly improving the MRR. Based on the results of experiment and analysis, the Mechanisms of Si substrate polishing in high-pressure O2 atmosphere were summarized and a material removal model was built.

A review: green chemical mechanical polishing for metals and brittle wafers

“…In recent years, most studies have focused on improving processing methods, preparing new abrasives and changing the composition of the slurries [20]. The surface quality has been indeed improved by optimizing the processing technology [21]. However, toxic and corrosive solutions are widely used in CMP slurries, thereby seriously polluting the environment.…”

Effect of Alkali Metal Ion on Chemical Mechanical Polishing of LiTaO3

“…CMP is a widely used surface machining method for various materials. [6][7][8] At present, some studies [9][10][11] have focused on CMP processing of LiTaO 3 wafer surface. Hyunseop Lee et al 9 studied the effect of additive citric acid on LiTaO 3 wafer during CMP processing.…”

Investigation of Particle Kinetic Energy for EKF-CMP Process

“…7 Additionally, chemical additives, particle size, particle hardness, particle deformation, and pH value of slurry, feed rate and temperature of slurry, slurry viscosity, slurry density, and the local slurry flow pressure, abrasive nanoparticle concentration (wt%) have also an influence on the surface polishing quality of the wafer. [8][9][10][11][12][13][14] The linear sliding velocity ratio between the rotational speed of wafer and the rotational speed of pad, the chemical reaction of the local slurry flow velocity, and the mechanical action of the abrasive nanoparticles on the pad surface affects directly the material removal rate. 15,16 Therefore, many researchers had developed a lot of mechanical models of the material removal rate to predict and optimize the surface cut rate for the metallization of the copper film during the CMP process.…”