Tribological, Thermal and Kinetic Characterization of SiO2and Si3N4Polishing for STI CMP on Blanket and Patterned Wafers

This study aims to develop a three-dimensional electro-osmosis flow (3D-EOF) cell model for effective particle analysis on the wafer at steady-state under electro-kinetic force (EKF) assistance during chemical mechanical polishing/planarization (CMP). A simulation software is used to simulate the abrasive particle motion with three functional modules including the electric current, the laminar flow, and the particle trajectories. Parameter designs of various simulation conditions such as electrode gap spacing, direct current voltages, and polishing pad thickness have been investigated to analyze the motion of silica abrasive nanoparticles due to EOF. Simulation results of the EOF velocity of slurry flow circulation in different conditions have compared with theoretical calculation results. Results have shown that the total number of effective particles intensifies significantly with increasing electrode voltage, but decreases in both cases as raising electrode gap and larger pad thickness. Experimental results of EKF-CMP process can improve 25.03%, 2.52 nm, 1.39% for material removal rate (MRR), surface roughness, non-uniformity, respectively. It can explain that the wafer surface polishing qualification is significantly by motion of effectual abrasive particles. Results of this study can be extended to contribute to improvement and optimization of EKF-CMP process for Copper CMP process used in IC fabrication.

Section: Mrr Kpv 1 [ ] =mentioning

confidence: 99%

Effective Particle Analysis on Wafer in the EKF-CMP System

Mai

Chen

et al. 2021

“…5 For example, the silicon dioxide (SiO 2 ) layer is used as the insulator in the shallow trench isolation (STI) CMP. [6][7][8] Silicon dioxide is used as the interlevel dielectric (ILD) layer during the barrier CMP process. 7 Silicon dioxide is used as a sacrificial layer in the gate formation technique in the replacement metal gate (RMG) integration scheme.…”

mentioning

confidence: 99%

Role of Slurry Additives on Chemical Mechanical Planarization of Silicon Dioxide Film in Colloidal Silica Based Slurry

Wang

Zhou

et al. 2021

Chemical mechanical planarization (CMP) is a critical process for smoothing and polishing the surfaces of various material layers in semiconductor device fabrication. The applications of silicon dioxide films are shallow trench isolation, an inter-layer dielectric, and emerging technologies such as CMOS Image Sensor. In this study, the effect of various chemical additives on the removal rate of silicon dioxide film using colloidal silica abrasive during CMP was investigated. The polishing results show that the removal rate of silicon dioxide film first increased and then decreased with an increasing concentration of K+, pH, and abrasive size. The removal rate of silicon dioxide film increased linearly as the abrasive concentration increased. The influence mechanisms of various additives on the removal rate of silicon dioxide film were investigated by constructing simple models and scanning electron microscopy. Further, the stable performance of the slurry was achieved due to the COO- chains generated by poly(acrylamide) hydrolysis weaken the attraction between abrasives. High-quality wafer surfaces with low surface roughness were also thus achieved. The desirable and simple ingredient slurry investigated in this study can effectively enhance the planarization performance, for example, material removal rates and wafer surface roughness.

“…It can be used for nano-level polishing of many hard and brittle materials, including silicon, 1,2 glass, 3,4 ceramics, 5 sapphire. 6 It can also be used to planarize metals such as W, 7 Cu, 8,9 Ni, 10 Ru 11 and compounds such as SiO 2 , 12 Si 3 N 4 , 12 GaAs 13 and InSb. 14,15 Traditional CMP machine is mainly composed with a rotating work platform (lower disc) carrying a polishing pad, several rotating polishing heads (upper discs) holding several wafers, a chemical polishing liquid supply system, a control system and so on.…”

mentioning

confidence: 99%

Thin Ferrite Wafer Uniformly Polished with Magnetic Attraction Method

Wang

Lin

et al. 2020

When a ferrite substrate is used to prepare thin-film InSb Hall element chips, one surface of the ferrite wafer needs to be polished. The traditional chemical mechanical polishing (CMP) method, often used for polishing of ferrite wafers, has several problems: a long time to install and remove wafers, a little high debris rate, and high cost. Taking advantage of the fact that ferrite wafers can be magnetically attracted, a method using independent RuFeB magnets to attract and hold ferrite wafers is proposed. The polishing head holding the ferrite wafer can perform planetary rotary motion to achieve uniform polishing. The polishing head floats up and down freely on the polishing pad, without the requirements of matching and process accuracy in machining, mechanical linkage, and control. The roughness of the ferrite surface after polishing is about 0.18 μm, which meets the requirements for the substrate of InSb Hall element chips. With no debris, the efficiency of installing and removing wafers is 30 times higher than that of traditional methods. At the same time, compared with traditional CMP machine, the cost of CMP equipment made by this method is very low.