Silicon carbide (SiC), with its wide band gap and high thermal conductivity, is increasingly favored for semiconductor power applications across several fast-growing industries. Its ability to operate at higher voltages and frequencies enables significant efficiency gains, particularly in e-mobility, where SiC offers key advantages in size, weight, and speed compared to traditional silicon-based power devices.However, as promising as SiC is, the industry still faces critical challenges in scaling to meet growing demand. Key barriers include cost, reliability, and manufacturing capacity, all of which must be addressed for SiC to fully mature.SEMI spoke with Entegris Senior Director - Advanced Technology Engagements, Office of the CTO Mark Puttock, Ph.D., to discuss the challenges of scaling SiC power chip manufacturing from a material supplier’s perspective. Puttock shared insights ahead of his presentation at the Entegris session, Cultivating a Thriving SiC Market: Tackling Key Challenges Across the Value Chain, taking place on November 14, 2024, at SEMICON Europa in Munich, Germany. Don’t miss the opportunity to engage with experts from Entegris and other industry leaders. Registration is now open. SEMI: Global megatrends like environmental crises and AI drive the necessity for SiC power semiconductors. What is the current status? Puttock: The increasing demand for efficient power electronics — fueled by global megatrends such as vehicle electrification, environmental de-carbonization, and the rise of power-hungry AI chips — drives the necessity of wide bandgap semiconductors. SiC offers advantages of weight, size, and speed over traditional silicon (Si) solutions, which are particularly vital in automotive applications 600V and above. However, SiC chip manufacturing has not reached the maturity of silicon-based processing. Greater maturity will help reduce costs, which will accelerate adoption in the market.SEMI: What are the main challenges in scaling SiC?Puttock: Challenges in scaling SiC power chip manufacturing to high volumes are not surprising. That’s because high volume producers have not been operating long enough to resolve early-stage issues. From a material perspective, SiC is more challenging to manage compared to Si. The challenges we identify include:Chemical Mechanical Planarization (CMP): SiC is nearly as hard as diamond and significantly harder than Si, making it challenging to achieve a high removal rate while maintaining both planarity and low defectivity. This step is crucial toward the end of the wafering process and before the epitaxial growth of device layers.Handling: SiC is more brittle than Si, making it more susceptible to damage or breakage.Implantation: SiC is more difficult to implant than Si, requiring higher temperatures and the use of aluminum instead of boron as a P-type implant species. Additionally, it is a significant challenge to achieve a reliable aluminum source with a long and stable lifetime.Thermal Processing for Wafer Growth and Epitaxy Processes: SiC processes run hotter than Si ( 2000° C for wafering, 1500° C for epitaxial growth), demanding resilient chamber parts to achieve good lifetimes.Sustainability: Because SiC is extremely hard, the CMP process requires significant amounts of slurry. Improving slurry recycling and wastewater management continues to be a challenge.On October 29, we will address these issues in our webinar, “Challenges in Scaling SiC Power Chip Manufacturing: A Material Supplier's Perspective” This session will provide valuable insights and considerations for advancing maturity in high-volume SiC power chip manufacturing. SEMI: Can you elaborate on the challenges associated with CMP for SiC wafers? Puttock: SiC wafers are challenging to process, requiring specialized materials and methods compared to traditional silicon. Defects in the SiC wafer crystal during non-optimized CMP processing can propagate into the device epitaxial layers. This leads to yield loss, increased electrical resistance, reduced performance, and wasted power.SiC wafers must be cut, ground, lapped, and polished to create the necessary surface properties before depositing active layers. As the demand for these devices grows, optimizing the CMP process is essential to ensure the desired surface quality and planarity required for device fabrication. For a deeper understanding of these challenges, we recommend downloading our latest white paper, “Solving CMP Challenges in High-Volume SiC Production,” which covers:Achieving maximum smoothness with high removal ratesReducing the total cost of ownership Optimizing CMP slurry and pads for the unique wafer chemistry and topology of SiC wafersSEMI: What do you mean by optimizing slurry for SiC CMP?Puttock: CMP slurry typically consists of abrasive nanoparticle powder dispersed in a chemically reactive solution. The objective is to achieve a smooth, defect-free surface (less than 1 A Ra) with a high removal rate (greater than 7 µm/m).Traditionally, achieving high removal rates and smooth surfaces required two separate slurries. This approach sometimes forced SiC wafer manufacturers to choose a defect-free surface over a faster, more efficient CMP process, depending on their fab capabilities. Today, optimization allows SiC wafer manufacturers to achieve both high polishing capacity and good final surface quality using a single slurry.Additionally, while the slurry is the most critical part of the CMP process, the pad must be compatible with the application. This ensures the desired planarity while also preventing scratches or contamination of the SiC wafer surface. Research shows that optimized thermoplastic polyurethane CMP pads outperform traditional thermoset polyurethane pads. The optimized pads minimize surface damage and enhance removal rates due to their bulk hardness.SEMI: What are the future challenges for SiC devices? Puttock: SiC devices are increasingly favored for their superior energy efficiency and reduced environmental impact. However, the SiC manufacturing process presents challenges due to its high-temperature operations, which consumes significant amounts of energy and shortens the lifespan of chamber components. To address this, improving efficiency in these processes will be crucial in the coming years.Recycling is another important challenge. For example, CMP slurries present an opportunity for water recycling and conservation. At Entegris, we are committed to this issue and are actively collaborating with key industry players to enhance material circularity and prioritize sustainability in our new product development.SEMI: How is Entegris contributing to advancements in SiC technology, and what initiatives or partnerships do you have planned for the near future? Puttock: Entegris is an active member of the SEMI Global Automotive Advisory Council (GAAC) and participates in a working group focused on SiC with key industry leaders such as Volkswagen, BMW, Porsche Consulting, onsemi, Infineon, STMicroelectronics, and others. Our engagement spans the entire semiconductor supply chain, collaborating with integrated device manufacturers and original equipment manufacturers in fabs worldwide. Additionally, we recently announced our latest long-term agreement with onsemi, which underscores our commitment to advancing SiC technology.SEMI: What are your expectations regarding your participation at SEMICON Europa? Puttock: SEMICON Europa is a unique platform to connect with the semiconductor and automotive ecosystems. Last year, we organized a highly successful SiC session in collaboration with SEMI at both SEMICON West and SEMICON Europa, focusing on “Connecting the Automotive Ecosystem Towards More Mature SiC Manufacturing.”This year, we will continue the discussion with industry leaders during our session, “Cultivating a Thriving SiC Market: Tackling Key Challenges Across the Value Chain.” Our goal is to provide insights and propose solutions that will enable SiC power chips to achieve their anticipated role in future technology ecosystems.We will present alongside Porsche Consulting, and the talks will be followed by a panel discussion that will explore the current state and future prospects of SiC technology in power electronics. We invite visitors to join us at the Executive Forum on Thursday, November 14, from 1:40 – 3:00 p.m. and to visit us at Silicon Saxony booth 219 in Hall C1.About Mark PuttockMark Puttock, Ph.D., is the senior director of advanced technology engagements in the office of the CTO at Entegris. He has worked in the semiconductor industry for over 30 years with a background in physics and plasma processing. As a team member of the Entegris CTO office since 2014, Mark has followed technology trends and collaborated with Entegris’ global product development teams to develop timely and differentiated new materials, chemistries, and components for all the world’s semiconductor manufacturers. Maria Daniela Perez is Communications Manager at SEMI Europe.
