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Power Semiconductors: Technical Challenges and Future Development Paths

Power Semiconductors: Technical Challenges and Future Development Paths
Power Semiconductors: Technical Challenges and Future Development Paths

In 2024, when science and technology are changing with each passing day, the semiconductor industry, as the cornerstone of information technology, is standing at a new historical starting point. In the face of fierce competition and rapid change in the global semiconductor market, how to break through technical barriers and achieve independent and controllable has become an important topic for Chinese semiconductor companies. It is based on this background that the "12th (2024) Semiconductor Equipment Annual Conference - 2024 Power and Compound Semiconductor Industry Development Theory" was grandly opened at Wuxi Taihu International Expo Center in the golden autumn season, bringing together many leaders and industry elites in the semiconductor field at home and abroad to discuss the future development trend of semiconductor manufacturing and core components, and draw a new blueprint for the semiconductor industry.

Power Semiconductors: Technical Challenges and Future Development Paths

Liu Guoyou, deputy director of the National Key Laboratory of Power Semiconductor and Integrated Circuit Technology

Liu Guoyou, deputy director of the National Key Laboratory of Power Semiconductors and Integrated Circuit Technology, said that silicon carbide technology is undoubtedly the main technological development direction in the future, and this conclusion is based on the significant material advantages in the field of power devices. The superior performance of power semiconductor devices in terms of voltage frequency, temperature tracking, and loss enables them to significantly reduce overall losses in the system and reduce the need for heat dissipation, thereby significantly improving system efficiency.

Silicon carbide technology is developing rapidly, and silicon-based devices are not stagnant, and technology research and development is being carried out in the direction of lower losses. This includes a refined trench design, further downsizing to reduce losses, and technical optimization at the end and in the active area. At the same time, the continuous progress of multi-channel, multi-gate and other technologies is also promoting the development of silicon carbide devices, making them occupy an advantage in the performance competition with silicon-based IGBTs.

In the field of packaging, in addition to reducing chip loss, the overall performance of power semiconductor devices can also be improved through the optimization of packaging technology. Liu Guoyou added that the current progress and challenges of silicon carbide technology. Silicon carbide devices face problems such as growth rate, defect density and P-type doping in terms of material technology. In terms of process technology, the processing of ultra-high temperature and superhard materials is also a major challenge; Chip technology involves issues such as anisotropy, gate oxygen, bipolar degradation, and ohmic contact. In terms of packaging technology, it is necessary to solve the problems of low-inductance, high-temperature and high-voltage packaging; In the field of application technology, due to the high frequency of silicon carbide, it also faces great challenges in terms of drive protection and high-voltage insulation.

Power Semiconductors: Technical Challenges and Future Development Paths

Hu Jianzheng, Director of China Micro Semiconductor

Hu Jianzheng, director of China Micro Semiconductor, said that for the next generation of display technology in the future, the size of Micro LED chips is expected to be further reduced to the range of a few to tens of microns, which opens up more possibilities for its application and is widely expected to be regarded as the ultimate solution in the display field.

In the field of LED display, brightness was mainly pursued in the past, but now more attention is paid to the consistency of wavelength. The popular understanding of wavelength in the field of display is the purity of luminescent color, or the consistency of color. So, from a device manufacturing perspective, we need to produce products with a high degree of color consistency and sufficient purity. In achieving this, there are a number of factors to consider for the Ingan material system, including temperature consistency, the layout of the graphite tray, and the warping fit when carrying wafers and substrates. These are all aspects that require careful design in the growth process of single crystal materials, and how to ensure that the local turbulence during the growth process is effectively controlled, is also crucial.

Power Semiconductors: Technical Challenges and Future Development Paths

Chen Xianglong of Qingdao Sifang Sirui Intelligent Technology Company

Chen Xianglong of Qingdao Sifang Sirui Intelligent Technology Co., Ltd. said that the trench structure will bring more problems than the plane grid, and from the perspective of traditional thermal oxidation, when moving from the plane structure to the trench structure, it will face many challenges. First of all, during the thermal oxidation process, the oxidation rate of the silicon and carbon surfaces is different, resulting in a significant difference in the thickness of the oxide layer generated. This thickness inhomogeneity is especially noticeable in corners and can trigger a concentration of electric fields, which in turn increases the risk of leakage.

Second, even if the oxide layer formed by the silicon and carbon sides is of the same thickness, their electrical properties may be very different. This difference in electrical properties can exacerbate anisotropic problems, making the performance of the device difficult to predict and control.

For many domestic manufacturers, they may have struggled to meet these challenges in the past year, but found it quite difficult to solve. During thermal oxidation, the formation of carbon clusters becomes more serious as the depth increases, because the carbon atoms at the depths are difficult to release. This problem is unavoidable in both planar and trench structures, resulting in the deterioration of the interfacial density of states, which in turn affects the mobility. Therefore, the gate oxygen process is a major challenge in the manufacture of silicon carbide devices, whether it is a planar structure or a trench structure. How to control the generation of carbon clusters while ensuring the uniformity of the oxide layer is an urgent problem to be solved.

Power Semiconductors: Technical Challenges and Future Development Paths

Leuven Instruments Guo Chunxiang

According to Dr. Guo Chunxiang of Leuven Instruments, as automotive semiconductor technology continues to move towards the field of high voltage and high current, the iteration and innovation in the field of device manufacturing pose severe challenges to etching and manufacturing processes. The promotion of the entire semiconductor technology is divided into three levels: underlying device manufacturing, module manufacturing, and terminal applications, covering photovoltaic power generation, new energy, smart grid, rail transit and other fields. As a professional supplier of wafer fabrication equipment, Leuven Instruments is committed to working with customers to solve new problems in device manufacturing.

In recent years, device manufacturing has undergone a shift from discrete devices to planar MOSFETs to trench gate development, and the process challenges have become increasingly apparent. In the past, when it came to the silicon carbide industry, people often first thought of foreign companies, such as Infineon. Nowadays, however, more and more Chinese device manufacturers have set foot in this field and are actively engaged in the research and development of advanced processes. According to our data, in 2023, the main products shipped by domestic manufacturers will still be discrete devices and planar gates. On the whole, the development of China's silicon carbide industry is in a critical period of transition from plane grid to trench gate.

Power Semiconductors: Technical Challenges and Future Development Paths

Wuxi Yiwen Technology Ye Guoguang

Ye Guoguang of Wuxi Yiwen Technology said that MOCVD (organometallic vapor phase epitaxy), ion implantation, high-temperature annealing, high-temperature oxidation and ALD (atomic layer deposition) are relatively low-localization equipment, and they are also the technology and equipment fields that China is vigorously developing.

MOCVD technology is mainly divided into four categories: horizontal, planetary, vertical spray and high-speed turntable. Among them, the vertical spray type and high-speed turntable MOCVD equipment have achieved a high localization rate, and these two technologies are widely used in the manufacture of most optical devices. However, in terms of horizontal and planetary MOCVD, China is still catching up with the international advanced level, and most of the products in the market are still imported.

Mr. Ye Guoguang believes that the localization of MOCVD equipment is a long and arduous process, which requires patience and perseverance of local enterprises. Although some progress has been made in MOCVD equipment in the fields of LED, laser, gallium nitride devices and power devices, the performance of 12-inch advanced technology is still weak compared with the international advanced level.

Power Semiconductors: Technical Challenges and Future Development Paths

Oriental Jingyuan Jia Xiwen

Jia Xiwen said that the integrated circuit industry, especially in the field of equipment, is highly dependent on imports for advanced processes, and the development of technology is facing severe bottlenecks, especially in terms of quantity testing equipment, and the alternative road of localization is still full of challenges. From R&D to mass production, a chip manufacturing plant (FAB) needs to go through a scientific and rigorous process, including small batch trial production, overcoming power and yield problems, and reaching a stable and efficient mass production state.

According to Mr. Jia Xiwen's analysis, inspection and metrology are two crucial links in the whole process control stage. They are an indispensable means in the process of chip manufacturing and FAB production, and the needs and challenges of these two links are increasing as the process difficulty and complexity increases.

In this process, although Dongfang Jingyuan has many optical machines, electron beam technology is particularly important when carrying out small-dimensional detection and measurement. Electron beams have the unique advantage of meeting the needs of high precision and high resolution.

Dongfang Jingyuan's next-generation products will focus on advanced processes, and are committed to achieving a resolution of 1.45 nanometers, with a repeatable measurement accuracy of 0.15 nanometers for 80 nanometer linewidths, while maintaining a production capacity of 60 wafers, and ensuring that the uniformity of the machine is within 0.15 nanometers or 1% of CD. This is the high demand for CD (critical dimension) measurement equipment in advanced manufacturing processes.

Power Semiconductors: Technical Challenges and Future Development Paths

Shengmei Semiconductor Jin Yinuo

Shengmei Semiconductor Jin Yinuo said that the fourth generation of HBM4 uses RDL, TSV or micron-level electroplating process similar to double Damascus structure. The basic principles of electroplating are not complicated. There are three directions for the development of electroplating technology: first, the technical node of advanced technology shrinks; Second, the back conductive system released by Intel; 3. Compound semiconductors.

Power Semiconductors: Technical Challenges and Future Development Paths

Beijing San'an Optoelectronics Chen Dongpo

Dr. Chen Dongpo of Beijing San'an Optoelectronics said that the growth rate of silicon carbide from before 2023 is very fast, and the growth rate will slow down in 2024, mainly due to the slowdown in the growth rate of electric vehicles and the decline in prices.

For problem 1, on the supply side, there will indeed be a lot of concentrated production capacity before 2023, and the homogenization of the released production capacity is more serious, and technological progress is also the main reason. The quality and processing level of crystal production are improving, and the localization of equipment and materials also plays a great role in reducing costs. When the production capacity is released, in order to quickly occupy the market, the price will be lowered and the market will be exchanged for the price.

2. On the demand side, the imbalance in the development of the upstream of the supply chain and the chip end has led to the imbalance between the supply and demand of substrates, epitaxy and chips in the short term. In addition, the price of new energy vehicles this year is very high, which will pass the pressure on the device side. IGBTs are progressing very fast, and at the same time, gallium nitride is constantly coming to the car, putting pressure on silicon carbide.

3. The trend of fast switching between 6 and 8 inch wafers is increasing. The underlying logic is that 8 inches has the potential to reduce the cost of chips.

4. The diffusion speed of leading enterprises is accelerating.

5. The cross-border integration of the industry is very intense.

6. Domestic silicon carbide is accelerated on the car.

7. Industrial vertical integration is the mainstream trend.

Power Semiconductors: Technical Challenges and Future Development Paths

Shanghai Banyan Consulting Xu Ke

Mr. Xu Ke of Shanghai Banyan Consulting said that China is undoubtedly the world's largest silicon carbide power device application market, but the problems are also very prominent: 1. Structural imbalance, the material end is already very large in terms of volume, but the device end is still in the stage of breaking the game. 2. On the demand side, ST and Infineon are adjusting and reducing financial expectations. The biggest reason is that the growth rate of new energy vehicles is not as fast as imagined. 3. Foreign manufacturers are very aggressive in the manufacturing layout of 8-inch wafers, and Chinese manufacturers have rolled the substrate to overseas manufacturers, and no one dares to expand production.

Mr. Ke said that for the development of the silicon carbide industry, we must establish the advantage of the entire production capacity scale at the wafer device end.

Power Semiconductors: Technical Challenges and Future Development Paths