Development of the Local Polishing Technique for Single-Crystal SiC Wafer

2015 ◽  
Vol 656-657 ◽  
pp. 204-207 ◽  
Author(s):  
Shin Nagae ◽  
Akihisa Kubota ◽  
Mutsumi Touge
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Roughness ◽  
Single Crystal ◽  
Hydrogen Peroxide Solution ◽  
Dramatic Improvement ◽  
Single Crystal Sic ◽  
Method Effects ◽  
Sic Wafer ◽  
Surface Microroughness

We have developed a novel polishing technique by scanning a small magnetic tool in hydrogen peroxide solution for smoothing a 2-inch SiC wafer. Obtained results show that the surface roughness in almost areas on the 2-inch SiC wafer is improved markedly. Our proposed method effects a dramatic improvement in a surface microroughness from 0.699 nm Rms to 0.079 nm Rms.

Study on the Machining Parameters in Polishing Single-Crystal SiC Wafers with SG Films

2013 ◽  
Vol 589-590 ◽  
pp. 457-463 ◽  
Author(s):  
Zhi Du ◽  
Jing Lu ◽  
Cong Fu Fang ◽  
Hui Huang ◽  
Xi Peng Xu
Keyword(s):  
Surface Roughness ◽  
Single Crystal ◽  
Smooth Surface ◽  
Sol Gel ◽  
Machining Parameters ◽  
Processing Quality ◽  
Rotating Speed ◽  
Single Crystal Sic ◽  
Sic Wafer ◽  
Diamond Abrasive

In this paper, diamond abrasive SG films were prepared by means of sol-gel technology for polishing single-crystal SiC wafers. The effects of machining parameters on processing quality including pressure, rotating speed and polishing time were investigated, respectively. The results indicated that the surface roughness decreased with increasing polishing time. While for pressure and rotating speed, there were inflections existing. Polishing SiC wafer under optimized machining parameters, an ultra smooth surface with the roughness of 3.7 nm could be achieved using 40 μm diamond grits.

scholarly journals Investigation on the Material Removal and Surface Generation of a Single Crystal SiC Wafer by Ultrasonic Chemical Mechanical Polishing Combined with Ultrasonic Lapping

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2022 ◽  
Author(s):  
Yong Hu ◽  
Dong Shi ◽  
Ye Hu ◽  
Hongwei Zhao ◽  
Xingdong Sun
Keyword(s):  
Surface Roughness ◽  
Single Crystal ◽  
Material Removal Rate ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Removal Rate ◽  
Surface Generation ◽  
Ultrasonic Assisted ◽  
Single Crystal Sic ◽  
Sic Wafer

A new method of ultrasonic chemical mechanical polishing (CMP) combined with ultrasonic lapping is introduced to improve the machining performance of carbide silicon (SiC). To fulfill the method, an ultrasonic assisted machining apparatus is designed and manufactured. Comparative experiments with and without ultrasonic assisted vibration are conducted. According to the experimental results, the material removal rate (MRR) and surface generation are investigated. The results show that both ultrasonic lapping and ultrasonic CMP can decrease the two-body abrasion and reduce the peak-to-valley (PV) value of surface roughness, the effect of ultrasonic in lapping can contribute to the higher MRR and better surface quality for the following CMP. The ultrasonic assisted vibration in CMP can promote the chemical reaction, increase the MRR and improve the surface quality. The combined ultrasonic CMP with ultrasonic lapping achieved the highest MRR of 1.057 μm/h and lowest PV value of 0.474 μm. Therefore this sequent ultrasonic assisted processing method can be used to improve the material removal rate and surface roughness for the single crystal SiC wafer.

Detection and Analysis of Subsurface Cracks of Single Crystal SiC Wafers Based on Cross-Sectional Microscopy Method

2014 ◽  
Vol 1027 ◽  
pp. 240-245
Author(s):  
Qiu Sheng Yan ◽  
Sen Kai Chen ◽  
Ji Sheng Pan
Keyword(s):  
Sample Preparation ◽  
Single Crystal ◽  
Crack Detection ◽  
Preparation Method ◽  
Subsurface Crack ◽  
Cross Sectional ◽  
Preparation Methods ◽  
Subsurface Cracks ◽  
Single Crystal Sic ◽  
Sic Wafer

For subsurface crack detection of single crystal SiC wafer, this paper proposed a cross-sectional cleavage detection method and compared with traditional cross-sectional sample preparation method. The characteristics and detection results of two cross-sectional sample preparation methods were compared and the subsurface crack characteristics in SiC wafer grinding were researched. The results show that the configurations and depth of subsurface cracks measured by two cross-sectional sample preparation methods were similar. The cross-sectional cleavage sample preparation method is simpler and more rapid in subsurface crack detection. The subsurface crack system of single crystal SiC wafer grinding mainly includes lateral crack and median crack.

scholarly journals Effects of Depth of Cutting on Damage Interferences during Double Scratching on Single Crystal SiC

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 519
Author(s):  
Duan Nian
Keyword(s):  
Single Crystal ◽  
Material Removal ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Particle Hydrodynamics ◽  
Single Crystal Sic ◽  
Smoothed Particle ◽  
Planarization Process ◽  
Material Removal Mode ◽  
Sic Wafer

In this work, the damage interference during scratching of single crystal silicon carbide (SiC) by two cone-shaped diamond grits was experimentally investigated and numerically analyzed by coupling the finite element method (FEM) and smoothed particle hydrodynamics (SPH), to reveal the interference mechanisms during the micron-scale removal of SiC at variable Z-axis spacing along the depth of cutting (DOC) direction. The simulation results were well verified by the scratching experiments. The damage interference mechanism of SiC during double scratching at micron-scale was found to be closely related to the material removal modes, and can be basically divided into three stages at different DOCs: combined interference of plastic and brittle removal in the case of less than 5 µm, interference of cracks propagation when DOC was increased to 5 µm, and weakened interference stage during the fracture of SiC in the case of greater than 5 µm. Hence, DOC was found to play a determinant role in the damage interference of scratched SiC by influencing the material removal mode. When SiC was removed in a combined brittle-plastic mode, the damage interference occurred mainly along the DOC direction; when SiC was removed in a brittle manner, the interference was mainly along the width of cutting; and more importantly, once the fragment of SiC was initiated, the interference was weakened and the effect on the actual material removal depth also reduces. Results obtained in this work are believed to have essential implications for the optimization of SiC wafer planarization process that is becoming increasingly important for the fabrication of modern electronic devices.

Preliminary Study on Highly Efficient Polishing of 4H-SiC by Utilization of Anodic Oxidation

2014 ◽  
Vol 1017 ◽  
pp. 509-514 ◽  
Author(s):  
Kazuya Yamamura ◽  
Kenji Hosoya ◽  
Yusuke Imanishi ◽  
Hui Deng ◽  
Katsuyoshi Endo
Keyword(s):  
Surface Roughness ◽  
Phosphoric Acid ◽  
Single Crystal ◽  
Anodic Oxidation ◽  
Chemical Mechanical Polishing ◽  
Oxidation Rate ◽  
Removal Rate ◽  
Experimental Results ◽  
Single Crystal Sic ◽  
Preliminary Study

Preliminary study on anodic-oxidation-assisted polishing (AOAP) of 4H-SiC (0001) using ceria polishing film was demonstrated. In the case of using deionized (DI) water as an electrolyte, rms roughness of 0.16 nm was obtained, which is almost the same as roughness of the surface finished by conventional chemical mechanical polishing (CMP). However, the polishing rate was very low and was 23 nm/h. In contrast, the polishing rate of 0.84 μm/h, which is equal to that of conventional CMP of single-crystal SiC or greater, was obtained when we used 1 wt% of phosphoric acid (H3PO4) as the electrolyte, although the surface roughness increased to rms roughness of 1 nm order. These experimental results indicate that the polishing rate greatly depends on the oxidation rate of anodic oxidation and the balance between the oxidation rate and the removal rate of oxide by abrasive greatly affects the roughness of the processed surface.

scholarly journals Study on Improving the Precise Machinability of Single Crystal SiC by an Ultrasonic-Assisted Hybrid Process

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7320
Author(s):  
Dong Shi ◽  
Tianchen Zhao ◽  
Tengfei Ma ◽  
Jinping Pan
Keyword(s):  
Single Crystal ◽  
High Efficiency ◽  
Surface Defects ◽  
Removal Rate ◽  
Oxide Semiconductor ◽  
Hybrid Process ◽  
Ultrasonic Assisted ◽  
Single Crystal Sic ◽  
Surface Damages ◽  
Sic Wafer

Silicon carbide (SiC) devices have become one of the key research directions in the field of power electronics. However, due to the limitation of the SiC wafer growth process and processing capacity, SiC devices, such as SiC MOSFET (Metal-oxide-semiconductor Field-effect Transistor), are facing the problems of high cost and unsatisfied performance. To improve the precise machinability of single-crystal SiC wafer, this paper proposed a new hybrid process. Firstly, we developed an ultrasonic vibration-assisted device, by which ultrasonic-assisted lapping and ultrasonic-assisted CMP (chemical mechanical polishing) for SiC wafer were fulfilled. Secondly, a novel three-step ultrasonic-assisted precise machining route was proposed. In the first step, ultrasonic lapping using a cast iron disc was conducted, which quickly removed large surface damages with a high MRR (material removal rate) of 10.93 μm/min. In the second step, ultrasonic lapping using a copper disc was conducted, which reduced the residual surface defects with a high MRR of 6.11 μm/min. In the third step, ultrasonic CMP using a polyurethane pad was conducted, which achieved a smooth and less damaged surface with an MRR of 1.44 μm/h. These results suggest that the ultrasonic-assisted hybrid process can improve the precise machinability of SiC, which will hopefully achieve high-efficiency and ultra-precision machining.

Surface Finishing of Single-Crystal SiC and GaN Wafers Using a Magnetic Tool in H2O2Solution

2019 ◽  
Vol 13 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Akihisa Kubota ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Roughness ◽  
Removal Rate ◽  
Hydrogen Peroxide Solution ◽  
Surface Finishing ◽  
Oh Radicals ◽  
Atomic Step ◽  
Convex Part ◽  
Atomic Force ◽  
Before And After

To remove the microroughness and subsurface damage on the SiC and GaN surface efficiently, a surface finishing technique using a magnetic tool holding iron particles in a hydrogen peroxide solution is developed. This technique utilizes OH radicals generated from the iron catalytic particles in a hydrogen peroxide solution, and can be used to preferentially remove the topmost convex part on the surface, resulting in an atomically smooth surface. We employed this polishing technique to finish the surfaces of 2-inch SiC and 2-inch GaN wafers. The surface roughness before and after finishing was measured by scanning white light interferometric microscopy and atomic force microscopy. In addition, the material removal rate was calculated by weight loss due to the finishing process. The results show that the surface roughness on the SiC and GaN wafers is markedly improved. Moreover, the surface waviness and flatness of these wafers before and after finishing did not deteriorate. Atomic force microscope images indicate that an atomically flat SiC surface with a roughness value below 0.1 nm RMS and a GaN surface with atomic step and terrace structures were achieved. Our proposed finishing technique is effective in improving the surface microroughness of SiC and GaN wafers.

Effect of Abrasives on the Lapping Performance of 6H-SiC Single Crystal Wafer

2013 ◽  
Vol 690-693 ◽  
pp. 2179-2184 ◽  
Author(s):  
Wei Li ◽  
Qiu Sheng Yan ◽  
Jia Bin Lu ◽  
Ji Sheng Pan
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Single Crystal ◽  
Material Removal Rate ◽  
Material Removal ◽  
High Efficiency ◽  
Removal Rate ◽  
Lower Surface ◽  
Crystal Wafer ◽  
Sic Wafer

In order to remove the cutting marks on the cutting surface of 6H-SiC single crystal wafer, experiments were conducted to investigate the effect of the abrasive characteristics (types, grain size, concentration and mixed abrasives) on the lapping performance of 6H-SiC single crystal wafer, then the removal mechanism of the abrasive grains in the lapping process was studied. Results indicate that the abrasives with larger grain size and higher hardness can result in a higher material removal rate while the abrasives with smaller grain size and lower hardness can achieve a lower surface roughness value. When the concentration of the abrasives is 7.69 wt%, a good lapping effect was obtained. Lower surface roughness value Ra can be obtained with a high material removal rate by using certain proportion mixed abrasives. Selecting appropriate abrasives can obtain a high surface quality of 6H-SiC wafer with a high efficiency.

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