Benefits of Ultrasonic Grinding Silicon Carbide Change the World of Wafer Fabrication 2023/11/22 About Silicon Carbide (SiC) and Its Common Use in Semiconductor Manufacturing Process Silicon Carbide (SiC) Material Properties (Figure 1. HIT ultrasonic-assisted machining of silicon carbide workpieces, including SiC shaft seal, SiC micro-drilling, and SiC helical circular ramping) Silicon carbide (SiC) has been an extremely popular material in recent years due to the rapid rise of importance of semiconductor and electric vehicles application. Here are some typical material properties of silicon carbide: - High Hardness and Good Mechanical Strength - Silicon carbide is an extremely hard material, ranking close to diamond on the Mohs scale (Mohs hardness rating of 9). This hardness makes it highly wear resistant and thus has good mechanical strength. This makes silicon carbide an exceptional material choice for high precision mechanical components, which can withstand mechanical loads and stress. - Excellent Thermal Conductivity and Stability - Silicon carbide has a very high melting point (approximately 2,700°C or 4,892°F) and is resistant to thermal shock. This property allows it to maintain its structural stability even in oxidizing and corrosive environments under elevated temperatures. The material exhibits excellent thermal conductivity, making it an effective heat conductor. - Electrical Conductivity - Silicon carbide can be both a semiconductor and a conductor, depending on its crystal structure. The material is valuable for power electronics and high-frequency RF devices due to its wide bandgap (WBG). (Read more on What Are Wide Bandgap Power Supplies?) The bandgap of a semiconductor material determines the amounts of energy required to move an electron to the conduction band and acted as a conductor. Traditionally, silicon has been the primary material used for semiconductors. Being as a wide bandgap material, silicon carbide can be thinner than silicon to sustain the same voltage applied. This results in lower conduction and switching losses compared to silicon-base devices. 💡 Learn more on Silicon Carbide (SiC) Properties and Applications Common Use of Silicon Carbide (SiC) in Semiconductor Wafer Foundry Process Key spare parts within the semiconductor manufacturing chamber that are made of silicon carbide (SiC) are essential for various applications in the wafer foundry process. Some of the important silicon carbide spare parts include: - SiC Wafer Substrates and Wafer Susceptors - SiC wafer substrates serve as the foundation for the epitaxial growth of other semiconductor materials, such as gallium nitride (GaN). (Learn more on Silicon Carbide Substrates for Power Electronics) These substrates are crucial for the manufacture of high-performance and high-frequency electronic devices. (Figure 2. Silicon carbide wafer susceptors used in MOCVD process for epitaxial growth - source: AIXTRON Group) SiC-coated susceptors are used in chemical vapor deposition (CVD) and metal-organic chemical vapor deposition (MOCVD) processes for epitaxial growth. (Read more on How MOCVD Works) They are designed to withstand high temperatures and corrosive environments while supporting the growth of thin films and epitaxial layers. - SiC Etch Chambers and Showerheads - SiC is used to fabricate etch chambers and components within the etch chambers (such as SiC showerheads) for processes like plasma etching and chemical vapor deposition. (Learn more on how HIT applied ultrasonic-assisted machining technology on silicon carbide micro-drilling for showerheads) (Figure 3. HIT ultrasonic-assisted machining of silicon carbide micro-drilling for semiconductor showerheads application) The excellent thermal stability and corrosion resistance properties make silicon carbide a durable choice for these applications. - SiC Bearings and Seals - In semiconductor manufacturing equipment, SiC bearings and seals are used due to their excellent wear resistance, thermal stability, and chemical inertness. (Learn more on how HIT applied ultrasonic-assisted machining technology on silicon carbide milling for shaft seals) These material properties help maintain the integrity and stability of processing chambers and vacuum environments. - SiC Ceramic Nozzles and Liners for Wet Cleaning in Process Chamber - SiC nozzles and liners are used in plasma etching and wet cleaning processes, where aggressive and corrosive chemicals are involved under elevated temperatures. (Learn more on What is Plasma Etching and why it is Important for Product Development?) The chemical resistance and thermal stability material properties of silicon carbide are advantageous under this context. Mechanism of Silicon Carbide (SiC) Grinding In the initial stages of grinding, abrasive grains on the grinding tool plow into the surface of silicon carbide workpiece, creating grooves or scratches. This is mainly due to the hardness of the abrasive grains and their contact with the workpiece. (Figure 4. HIT ultrasonic-assisted grinding of silicon carbide for the making of wafer susceptors) As grinding continues, the abrasive grains begin to cut into the silicon carbide material. This cutting action is responsible for the removal of material and the generation of the desired shape and surface finish. Some silicon carbide material may fracture under the high grinding forces generated during the grinding process. This can lead to the formation of micro-cracks and help with the removal of material. 💡 Learn more on Grinding characteristics, material removal and damage formation mechanisms in high removal rate grinding of silicon carbide Difficulties in Silicon Carbide (SiC) Grinding Grinding silicon carbide can be challenging due to its unique material and mechanical properties. Some of the difficulties associated with silicon carbide grinding include: Hardness and Brittleness Silicon carbide is an extremely hard material, ranking at 9 on Mohs scale of hardness (close to diamond). This hardness can lead to excessive wear and rapid dulling of grinding tools/wheels. Silicon carbide material is also very brittle, which means it is prone to fracturing during grinding. The increasing grinding forces can induce chipping and edge-cracks in the material, affecting the quality of the finished surface. High Friction and Increasing Grinding Forces High friction between the grinding tool and silicon carbide workpiece mainly result from ceramic particles (silicon carbide material debris) accumulation on the pores (between abrasive grains) of grinding tool. Poor ceramic particle evacuation can lead to the declination of tool's grinding capacity, and thus resulting in the increase of grinding forces. Tool Wear and Tool Dressing Grinding tools/wheels for the grinding of silicon carbide can wear down very quickly due to rapid loss of grinding capacity because of poor particle evacuation, requiring frequent replacement and increasing the cost of the grinding process. Regular dressing of the grinding tool/wheel is necessary to maintain its sharpness and prevent loading of abrasive grains with silicon carbide material debris, which can lead to poor grinding efficiency. However, regular tool dressing usually takes up a huge amount of process time, and the grinding tool would inevitably have additional wear during the tool dressing process. This is not only time-consuming, but it could also lead to rapid declination of tool's grinding ability. What Does HIT Ultrasonic Machining Bring to Silicon Carbide (SiC) Grinding? Ultrasonic High Frequency Oscillation HIT's ultrasonic-assisted machining technology provides the superimposition of the tool rotation with a high-frequency oscillation in longitudinal direction, generating over 20,000 times of micro-vibration per second. The mechanism helps reduce grinding forces and facilitates ceramic particle flushing. (Figure 5. HIT ultrasonic-assisted machining technology with high frequency oscillation in longitudinal direction facilitates chip removal process) The high-frequency oscillation in longitudinal direction allows for an intermittent contact between the tool and workpiece. This helps eliminate accumulative heat around the grinding tool, which results in great reduction in tool wear. Reduction in Grinding Forces The reduction in grinding forces not only decreases frictions between the tool and workpiece, but also allows cutting speed and feed rate to be increased. This mechanism also helps lower the heat generated during the machining process. It greatly improves the workpiece quality and stability in tool life and saves a huge amount of energy and total process time. Better Particle Flushing Facilitating ceramic particle flushing also reduces frictions on both tool and workpiece caused by excessive particles stuck on the grinding tool/wheel. If the pores (between abrasives) of the grinding tool were filled with accumulative ceramic particles, the tool would quickly lose its grinding ability. (Figure 6. Explanation on self-sharpening mechanism of grinding tools/wheels - source: Testbook Edu Solutions Pvt. Ltd.) The high frequency micro-vibration of ultrasonic brings better particle flushing, which helps generate the self-sharpening mechanism (worn-out abrasive grits fall off, and new diamond grits come out to continue grinding) of grinding tool/wheel. This can greatly reduce the time and tool wear from tool dressing process. 💡 Learn more on Self-sharpening tendency of a conventional grinding wheel depends upon Benefits of HIT Ultrasonic in Grinding of Silicon Carbide (SiC) In grinding of silicon carbide, HIT ultrasonic-assisted machining technology helps reduce grinding forces and brings better particle flushing. This mechanism contributes to much shorter process time (elimination of tool dressing process), better workpiece quality (reduced edge-cracks and better surface quality), and longer tool life (elimination of tool dressing process and prevention of accumulative ceramic particles). Two Successful HIT Cases of Silicon Carbide (SiC) Grinding Silicon Carbide (SiC): Surface Grinding (Figure 7. HIT ultrasonic-assisted grinding silicon carbide workpiece) HIT carried out grinding of silicon carbide by using HIT BT-30 ultrasonic machining module. The high frequency micro-vibration helped with better particle flushing. This effectively prevented pores of the grinding tool from being filled with cumulative silicon carbide ceramic particles. (Figure 8. Comparison of workpiece quality between HIT ultrasonic-assisted machining and without ultrasonic on silicon carbide grinding) The lowered and stable grinding forces helped reduce chipping or cracks on the edge of workpiece with consistent size of tool marks on the surface. (Figure 9. Comparison of tool wear between HIT ultrasonic-assisted machining and without ultrasonic on silicon carbide grinding) The self-sharpening mechanism of grinding tool was generated and the new diamond grits came out to restore the grinding capacity. There was no need for tool dressing, so the total tool wear only came from the grinding process. 💡 See detailed information of Silicon Carbide (SiC): Surface Grinding Silicon Carbide (SiC) Grinding: (Helical) Circular Ramping (Figure 10. HIT ultrasonic-assisted grinding - helical circular ramping silicon carbide workpiece) HIT carried out (helical) circular ramping - grinding on silicon carbide by using HIT BT-30 ultrasonic machining module. The high frequency micro-vibration helped reduce grinding forces. This resulted in great improvement in the surface quality and mitigation of tool marks. (Figure 11. Comparison of surface roughness between HIT ultrasonic-assisted machining and without ultrasonic on silicon carbide grinding helical circular ramping) HIT utlrasonic-assisted machining technology in rough grinding process helped improve surface roughness (Sa) and tool marks. This allowed for reduction in post-process time, which also increased machining efficiency. (Figure 12. Comparison of tool wear between HIT ultrasonic-assisted machining and without ultrasonic on silicon carbide grinding helical circular ramping) The high frequency micro-vibration helped with better particle flushing. Much less and slower accumulation of ceramic particles on the grinding tool helped reduce grinding forces. This not only resulted in less tool wear, but also higher surface quality. 💡 See detailed information of Silicon Carbide (SiC) Grinding: (Helical) Circular Ramping 📺 Watch how HIT ultrasonic-assisted grinding of silicon carbide - (helical) circular ramping 📺 Watch more HIT Ultrasonic-assisted Advanced-Material Machining Videos Silicon Carbide (SiC) Grinding FAQ Q1 How is HIT ultrasonic able to reduce edge chipping or edge-cracks on the silicon carbide (SiC) grinding workpiece? A1 The high frequency micro-vibration of ultrasonic can help reduce grinding forces. Since the oscillation amplitude of ultrasonic is very small, the goal is to create micro-cracks on the molecular chains of silicon carbide material in order to facilitate material removal process. Serious edge chipping or edge-cracks on the silicon carbide workpiece usually resulted from much stronger vibration generated by the machine itself during the process. This also leads to poor precision and surface quality of workpiece. 💡 More information on HIT Ultrasonic-assisted Machining Technology Q2 How to adjust machining parameters, such as feed rate, cutting speed, or ultrasonic power, when I start grinding silicon carbide material with HIT's ultrasonic machining module? A2 Hantop Intelligence Tech. is a professional advanced-material machining process technology and smart automation modules supplier. It aims to provide not only high-quality ultrasonic-assisted machining module products, but also professional knowledge on how to optimize the benefits customers can achieve with the ultrasonic-assisted machining technology. This includes *providing the optimized machining parameters (according to the target material and machining features) and services to ensure customers having the best experiences in using HIT ultrasonic machining module. Customers are not just purchasing a product from HIT but obtaining ultrasonic machining process technology and services from the most professional and dedicated team. ⚠️*Providing the optimized machining parameters may come with additional fee depending on further negotiation. (Figure 13. HIT ultrasonic-assisted machining module products) 💡 More information on HIT Ultrasonic Machining Products Silicon Carbide (SiC) Grinding? Choose HIT Ultrasonic Process Technology Contact us if you are looking for a better way to improve machining efficiency, workpiece quality, and tool life. Or apply to become our international sales partners! Fill out the Application Form to become our international distributor. *References: AZO Materials Astrodyne TDI ASUZAC Co., Ltd. Accuratus AIXTRON Group Coherent Corp. Morgan Advanced Materials Thierry Corp. Testbook Edu Solutions Pvt. Ltd. ←Back