High-Efficiency Chemical Mechanical Polishing of Ti-6Al-4V Alloy via the Synergistic Action of H2O2 and K+ Under Alkaline Conditions

Author(s):  
Changbang Deng ◽  
Liang Jiang ◽  
Linmao Qian

Abstract Ti-6Al-4V (TC4) alloy has been widely used for implants, and excellent surface quality is required for satisfactory performance. In this study, chemical mechanical polishing (CMP) was introduced to process TC4 alloy. H2O2 and K+ were used to enhance the CMP efficiency. It is revealed that, at pH 10, the material removal rate (MRR) of TC4 alloy increases with the increasing H2O2. A synergistic action between H2O2 and K+ exists under alkaline conditions. With H2O2 and at pH 10, as the K+ concentration increases, the MRR of TC4 alloy first increases and then levels off. The anions have little influence on the CMP performance. After polishing, the surface is smooth without scratches, and the substrate underneath the surface film has no processing damage. For the synergistic action, K+ ions are adsorbed on the Stern layer of the TC4 alloy surface and the silica particles, screening the surface negative charge. Firstly, OOH- produced from H2O2 and OH- can approach the TC4 alloy surface easily, promoting the corrosion. Secondly, more silica particles come into contact with the TC4 alloy surface, enhancing the interactions. Therefore, the MRR increases. The research work brings about a promising high-efficiency CMP process for titanium alloys.

2002 ◽  
Vol 732 ◽  
Author(s):  
Zhenyu Lu ◽  
Seung-Ho Lee ◽  
Egon Matijević ◽  
S. V. Babu

AbstractThe properties of abrasive particles play a key role in chemical mechanical polishing (CMP). This study used well-defined dispersions of uniform particles, including spherical silica of varying diameters to polish Cu films and silica cores coated with nanosized ceria particles to polish oxide films. It was shown that the total surface area of the silica abrasives in the slurry controlled Cu material removal rate. However, pH, solid content, and particle size of ceria coated silica abrasives did not have a strong correlation to the removal rate of oxide films.


2008 ◽  
Vol 600-603 ◽  
pp. 831-834 ◽  
Author(s):  
Joon Ho An ◽  
Gi Sub Lee ◽  
Won Jae Lee ◽  
Byoung Chul Shin ◽  
Jung Doo Seo ◽  
...  

2inch 6H-SiC (0001) wafers were sliced from the ingot grown by a conventional physical vapor transport (PVT) method using an abrasive multi-wire saw. While sliced SiC wafers lapped by a slurry with 1~9㎛ diamond particles had a mean height (Ra) value of 40nm, wafers after the final mechanical polishing using the slurry of 0.1㎛ diamond particles exhibited Ra of 4Å. In this study, we focused on investigation into the effect of the slurry type of chemical mechanical polishing (CMP) on the material removal rate of SiC materials and the change in surface roughness by adding abrasives and oxidizer to conventional KOH-based colloidal silica slurry. The nano-sized diamond slurry (average grain size of 25nm) added in KOH-based colloidal silica slurry resulted in a material removal rate (MRR) of 0.07mg/hr and the Ra of 1.811Å. The addition of oxidizer (NaOCl) in the nano-size diamond and KOH based colloidal silica slurry was proven to improve the CMP characteristics for SiC wafer, having a MRR of 0.3mg/hr and Ra of 1.087Å.


2005 ◽  
Vol 867 ◽  
Author(s):  
Suresh B. Yeruva ◽  
Chang-Won Park ◽  
Brij M. Moudgil

AbstractChemical mechanical polishing (CMP) is widely used for local and global planarization of microelectronic devices. It has been demonstrated experimentally in the literature that the polishing performance is a result of the synergistic effect of both the chemicals and the particles involved in CMP. However, the fundamental mechanisms of material removal and the interactions of the chemical and mechanical effects are not well understood. A comprehensive model for CMP was developed taking into account both the chemical and mechanical effects for monodisperse slurries. The chemical aspect is attributed to the chemical modification of the surface layer due to slurry chemistry, whereas the mechanical aspect is introduced by indentation of particles into the modified layer and the substrate depending on the operating conditions. In this study, the model is extended to include the particle size and pad asperity distribution effects. The refined model not only predicts the overall removal rate but also the surface roughness of the polished wafer, which is an important factor in CMP. The predictions of the model show reasonable agreement with the experimental observations.


Author(s):  
Dinc¸er Bozkaya ◽  
Sinan Mu¨ftu¨

The necessity to planarize ultra low-k (ULK) dielectrics [1], and the desire to reduce polishing defects leads to use of lower polishing pressures in chemical mechanical polishing (CMP). However, lowering the applied pressure also decreases the material removal rate (MRR), which causes the polishing time for each wafer to increase. The goal of this work is to investigate effects of pad porosity and abrasive concentration on the MRR.


2018 ◽  
Author(s):  
Zewei Yuan ◽  
Kai Cheng ◽  
Yan He ◽  
Meng Zhang

The high quality surface can exhibit the irreplaceable application of single crystal silicon carbide in the fields of optoelectronic devices, integrated circuits and semiconductor. However, high hardness and remarkable chemical inertness lead to great difficulty to the smoothing process of silicon carbide. Therefore, the research presented in this paper attempts to smooth silicon carbide wafer with photocatalysis assisted chemical mechanical polishing (PCMP) by using of the powerful oxidability of UV photo-excited hydroxyl radical on surface of nano-TiO2 particles. Mechanical lapping was using for rough polishing, and a material removal model was proposed for mechanical lapping to optimize the polishing process. Several photocatalysis assisted chemical mechanical polishing slurries were compared to achieve fine surface. The theoretical analysis and experimental results indicate that the material removal rate of lapping process decreases in index form with the decreasing of abrasive size, which corresponds with the model developed. After processed with mechanical lapping for 1.5 hours and subsequent photocatalysis assisted chemical mechanical polishing for 2 hours, the silicon carbide wafer obtains a high quality surface with the surface roughness at Ra 0.528 nm The material removal rate is 0.96 μm/h in fine polishing process, which is significantly influenced by factors such as ultraviolet irradiation, electron capture agent (H2O2) and acidic environment. This combined method can effectively reduce the surface roughness and improve the polishing efficiency on silicon carbide and other hard-inert materials.


2020 ◽  
Vol 10 (22) ◽  
pp. 8065
Author(s):  
Linlin Cao ◽  
Xiang Zhang ◽  
Julong Yuan ◽  
Luguang Guo ◽  
Teng Hong ◽  
...  

Sapphire has been the most widely used substrate material in LEDs, and the demand for non-C-planes crystal is increasing. In this paper, four crystal planes of the A-, C-, M- and R-plane were selected as the research objects. Nanoindentation technology and chemical mechanical polishing technology were used to study the effect of anisotropy on material properties and processing results. The consequence showed that the C-plane was the easiest crystal plane to process with the material removal rate of 5.93 nm/min, while the R-plane was the most difficult with the material removal rate of 2.47 nm/min. Moreover, the research results have great guiding significance for the processing of sapphire with different crystal orientations.


2020 ◽  
Vol 866 ◽  
pp. 115-124
Author(s):  
Zhan Kui Wang ◽  
Ming Hua Pang ◽  
Jian Xiu Su ◽  
Jian Guo Yao

In this paper, a series of chemical mechanical polishing (CMP) experiments for magnesia alumina (Mg-Al) spinel were carried out with different abrasives, and the materials removal rate (MRR) and surface quality was evaluated to explore their different effects. The scanning electron microscope (SEM) and laser particle size analyzer were also employed to test the micro-shape and size distribution of abrasives. Then, the mechanism of different effects with different abrasives was analyzed in CMP for Mg-Al spinel. Those experimental results suggest that different subjecting pressure ratios of abrasives to polishing pad with different abrasive are the key factors leading to difference polishing performances in CMP.


2008 ◽  
Vol 373-374 ◽  
pp. 820-823
Author(s):  
Sheng Li Wang ◽  
Y.J. Yuan ◽  
Yu Ling Liu ◽  
X.H. Niu

Chemical mechanical polishing (CMP) of copper films in alkaline slurries was investigated. In the copper CMP, the slurry was made by adding colloidal silica abrasive to de-ionized water.The organic alkali was added to adjust the pH, H2O2 was used as an oxidizer.The effects of varying polishing temperature, polishing pressure, slurry flow rate, organic alkali concentration and oxidizer concentration on removal rate were investigated in order to determine the optimum conditions for those parameters. It is shown the chemical composition of the slurry was 2%~3% oxidizer concentration, 3% organic alkali concentration and proper amount surfactant is reasonable. The solid concentration of the polishing slurry was fixed at 20% by weight. The removal rate of copper could reach 700nm/min and the surface roughness after CMP was 0.49nm.


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