On March 17-18, 2021, the Zhonghuan Advanced Photovoltaic Conference 2021 and Ningxia Zhonghuan Photovoltaic Materials Co., Ltd. 50GW (G12) solar-grade monocrystalline silicon material smart factory project kick-off ceremony was held in Yinchuan. Under the background of reducing costs and increasing efficiency, the large-size silicon wafers are unstoppable. As a leading monocrystalline silicon wafer company, Zhonghuan Co., Ltd. took the lead in launching G12 (210) wafers in 2019, making it possible for the module power to exceed 600W+. As the market's acceptance of 210mm-size components continues to increase, Zhonghuan will plan ahead and expand production first to meet rising downstream demand.

Silicon Technology

Shen Haoping, General Manager of Zhonghuan, said: “The semiconductor industry follows the rule of 6 inches, 8 inches, and 12 inches in materials, equipment, or specimens. The application of 210 silicon wafers in the photovoltaic industry has achieved the leapfrogging of the industry. This is also the determination and basis for Zhonghuan Co., Ltd. to open a 50GW solar-grade monocrystalline silicon material smart factory project in Yinchuan."

It is understood that from the development context of Brother Industrial Semiconductor, the increase in the size of silicon wafers can significantly reduce the production cost of semiconductor chips, and it has become an inevitable trend that the size will continue to increase. At present, the size of the semiconductor industry is accelerating the transition from 8 inches to 12 inches. The ever-changing size of photovoltaic silicon wafers is actually derived from semiconductor silicon wafers. After the successful development of 12-inch crystals, the largest wafer size corresponding to the output is 210 mm.

From the perspective of the industry, the advent of 210 silicon wafers will break the current photovoltaic bottleneck and help the industry to reduce costs in the next 2-3 years. However, it is no easy task to realize the replacement and iteration of silicon wafer size, which is supported by technological innovation ability and quality management level. When it comes to G12 crystal factory, we have to mention the core keyword "Industry 4.0". "This means higher production efficiency and higher product quality assurance." Wang Lin, deputy general manager of Zhonghuan New Energy Crystal BU, introduced. As the first industry 4.0 benchmark factory in the industry, the Zhonghuan Inner Mongolia Phase V plant passed remote The development of the centralized control crystal pulling system has achieved the level that one employee can remotely operate 96 single crystal furnaces while sitting in the office in 2020. This human-machine ratio is 3-4 times ahead of the industry.

Through the implementation of Industry 4.0 and the remote centralized crystal pulling system, the per capita annual output value of the Inner Mongolia Phase V plant has reached more than 3 million in 2020, and it is expected that the per capita annual output value will reach nearly 5 million in 2021; the ratio of man-machines will also double. Reached 192 units per capita. With unremitting efforts and innovation, Zhonghuan Co., Ltd. has continued its research and development in silicon wafer technology. According to Wei Chen, deputy general manager of Zhonghuan New Energy Chip BU, as the G12 delivery capacity continues to improve, the company is also thinking about the future direction of chip processing. "In the future, the focus of wafer processing will be mainly reflected in the three directions of thinning, improvement of quality consistency, and transformation of manufacturing methods. The most critical challenges are the improvement of the mechanical properties of the silicon wafer and the stability of the consistency of the silicon wafer performance."

Challenges to the mechanical properties of silicon wafers

In response to these challenges, Zhonghuan has solved the above-mentioned challenges through simulation and actual testing, selecting the diamond wire, reducing the solid content in the coolant, and adopting advanced mechanical principle design. "Follow the line of Industry 4.0, and then we will carry out intelligent transformation. Through the application of big data, data analysis and decision-making can be realized. This can greatly reduce the impact of process fluctuations on quality and reduce personnel interference. "The impact of manual work and the impact of personnel analysis and decision-making." Wei Chen said.

If 210 components are to truly achieve large-scale development, it is necessary to solve the problems of upstream and downstream adaptation and coordination. In this regard, Xusheng Wang, Canadian Senior Director of Technology Integration, said that as the photovoltaic industry enters the 600W era, the market has launched tracking brackets and inverters that are suitable for large-size components. At the same time as the meeting, the 600W+ photovoltaic open innovation ecological alliance also launched the "Deepening Collaboration and Helping the Whole Industry to Enter the 600W+ Era Proposal" to help the entire industry intending to achieve industrial upgrades to successfully enter the 600W+ high-power era and complete the industrial chain and product line upgrade.Editor/Xing Wentao