Smarter solar manufacturing: flexible control technology drives efficiency in single-crystal furnaces

PC-based control technology elevates semiconductor production for photovoltaic equipment  

Jingsheng Mechanical & Electrical from China is a leading provider of single-crystal furnaces for growing semiconductors used in photovoltaic equipment.  © Beckhoff  

To grow monocrystalline semiconductors, Jingsheng Mechanical & Electrical originally used separate systems for process control and temperature control. Now, with PC-based control technology from Beckhoff, the company has lowered costs and simplified automation system implementation and scalability. As a bonus, Beckhoff’s TwinCAT software helps keep intellectual property secure. 

Headquartered in China’s Zhejiang Province, Jingsheng Mechanical & Electrical Co., Ltd. (JSG) is a leading global supplier of high-end equipment for the semiconductor and photovoltaic industries. Over many years, JSG has built a reputation as a well-known supplier of crystal-growth technology for photovoltaic equipment. Originally, they used a conventional PLC and a temperature control system for automating its single-crystal furnaces. However, the temperature control offered only limited functionality and, in combination with the PLC, was deemed too unflexible.  

This led JSG to adopt a Beckhoff control platform consisting of an Embedded PC running TwinCAT automation software, and various EtherCAT terminals to easily and flexibly connect field devices via EtherCAT. The integrated control platform combined two systems into one with  more flexibility and adaptability. 

Stable process control is key  

Monocrystals can only be grown under precise conditions. First, silicon is melted in the furnace. Then, a monocrystalline seed crystal attached to a metal rod is dipped into the melt, starting the crystallization process. While the melt is kept at a specific temperature, the rod is slowly rotated and pulled upwards in a way that the material can deposit, until the crystal column, known as an ingot, reaches the proper diameter. The uniform crystal orientation offers high efficiency for monocrystalline semiconductors, which are cut into wafers and used in solar modules. 

An automation platform consisting of an Embedded PC (shown here: CX8080), TwinCAT software, and EtherCAT Terminals controls the semiconductor production for photovoltaics. © Beckhoff

Growing these crystals requires precise sequential control and stable process control for long periods of time, ranging from several days to two weeks. Maintaining a consistent temperature during this time is essential as uneven temperatures can cause polycrystalline material to grow, creating structural defects in the crystal lattice. In order to continuously operate the JSC’s furnaces, the control system must be able to process large amounts of data.  

This is no problem for the Beckhoff Embedded PCs. The industrial-grade DIN rail controllers are built to withstand harsh environmental conditions while running at top performance. JSG started with a CX1030 Embedded PC, but now uses a CX9020 or CX8080 as the central machine controller, depending on the project requirements. Because the controllers can always be scaled and upgraded with new CPUs, JSG can continuously optimize its production and reduce costs, increasing their competitiveness in this rapidly evolving field. 

JSG mainly uses TwinCAT 2 control software, but if the company ever needs extended functionality, the switch to TwinCAT 3 is simple, with only minor code changes requires to migrate a control project. TwinCAT also supports a wide range of communication protocols, enabling communication between the main control system and subsystems, such as for heating and generating magnetic fields.  

Prerequisite for growing high-quality monocrystalline semiconductors is continuous furnace operation in intervals of several days through to two weeks. © Beckhoff  

Seamless data transmission and exchange creates synergies and improves the overall efficiency of the system. According to Mr. Wang, Senior Specialist at JSG, "The TwinCAT software is mature and field-proven, and its flexible programming facilitates the processing of all kinds of data. In addition, the PC-based control architecture makes it easier to connect the controller to an MES system in order to exchange data between production and enterprise systems." 

For real-time communication via EtherCAT, JSG can choose from a wide range of EtherCAT Terminals. Mr. Wang explains, "EtherCAT distributed I/O modules bring great convenience to project implementation, with unrestricted topology flexibility and a huge range of diverse configuration options. Thus, we can select them based on the needs and cost requirements of different projects.” 

Code protection through sub-division of tasks 

Temperature control is one of the core components in single-crystal furnace control, and customers must keep this highly confidential. TwinCAT’s modular software makes this simple. Users can easily divide the entire control program into sets of subtasks based on their priority and assign different users to manage them independently. These different subtasks can exchange information through variable mapping, and TwinCAT runs each task when needed. 

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The modular design also makes software development and maintenance more flexible and efficient. Additionally, JSG adopts multi-PLC task processing to encapsulate the core process algorithm into a single PLC program. To keep the core algorithm program secure, JSG saves the program as binary code that cannot be decompiled. The complete program can then be installed simply by copying the binary code files to the target controller. 

Following the company's latest technological innovations, Mr. Wang says, "JSG's biggest advantage lies in the transition away from a traditional closed control system model towards configuration with software-based control with an open architecture. The platform enables the automatic creation of TwinCAT XAE configurations via high-level language programming, based on the TwinCAT Automation Interface. Using this interface, end customers can turn valuable knowledge regarding their own manufacturing processes into software modules. This greatly increases the capabilities of end users to develop customized processes and protect their innovations in order to improve their competitiveness." 

In 2023, a delegation from Jingsheng Mechanical & Electrical visited the Beckhoff global headquarters in Verl, where they were warmly received (from left to right): Dr. Chao He (Area Sales Manager for China, Beckhoff Germany), Dr. Changsheng Hua (Manager for Data Science and Engineering, Beckhoff China), Xingkai Ma (Managing Director of Beckhoff China), Hans Beckhoff (Managing Owner of Beckhoff), Dr. Jianwei Cao (Chairman of Jingsheng), Jin Tu (Assistant President, Jingsheng) and Kai Ristau (Head of International Sales, Beckhoff Germany). © Beckhoff

By consolidating process and temperature control into a single integrated system with the help of Beckhoff’s PC-based control platform, JSG has transformed the automation of their single-crystal furnaces for greater flexibility, scalability, and efficiency. With their place as a leader in photovoltaic equipment secured, the company’s future, and that of sustainable solar energy production, is bright.  

Ready to scale up efficiency and innovation in energy manufacturing? Contact your local Beckhoff sales engineer today.

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Shane Novacek is the Marketing Communications Manager at Beckhoff Automation