Senior PLC Software Engineer

Sioux Group was founded in 1996 in the Netherlands. With over 1,400 engineers, Sioux supports or acts as the R&D partner of leading high-tech companies. We aim to add value to our clients by developing innovative and high-tech solutions that contribute to a smarter, safer, healthier, more enjoyable, and more sustainable society.

Sioux has been recognized as an employer of choice, including awards such as Best ICT Company to Work For and Great Place to Work. In addition to our strong presence in Europe, Sioux is rapidly expanding in Asia, with offices in Vietnam, China, Singapore, and India.

With a strong heritage and a diverse international team, Sioux is proud of our core values: Own it and make it happen, Grow and innovate together, and Surprise customers. If these values resonate with you, we would love to welcome you to our team.

We are seeking highly motivated PLC Software Engineer(s) for semiconductor tools: wafer handling, process modules, vacuum systems, facilities (gas, chemical, cooling) and safety interlocks. The software must be safe, deterministic and fit for 24/7 fab operation.

You work across the full lifecycle. That means requirements, architecture, coding, simulation, factory acceptance, on-site commissioning at customer fabs, and field support after handover.

Key Responsibilities:

• Design and develop PLC programs to IEC 61131-3 (Structured Text, Ladder, Function Block Diagram, SFC) on platforms such as Beckhoff TwinCAT 3, Rockwell.
• Build modular, reusable libraries and state machines for motion, robots, load ports, valves, pumps, heaters and gas panels.
• Implement motion control for servo axes, stages and wafer-handling robots over EtherCAT, PROFINET, CC-Link IE or EtherNet/IP.
• Develop alarm handling, recipe management, data logging and HMI interfaces with the equipment controller or tool software.

Semiconductor integration and compliance

• Implement host communication with SECS/GEM (SEMI E5, E30), GEM300 (E40, E87, E90, E94) and, where needed, Interface A / EDA (E120, E125, E132).
• Integrate with AMHS/OHT, E84 load-port handoff and fab MES interfaces.
• Design safety interlocks and ensure compliance with SEMI S2 / S8 and functional safety standards (IEC 61508, ISO 13849), including safety PLCs and TwinSAFE or PROFIsafe.

Testing and commissioning

• Write and run unit, integration and simulation tests, including virtual commissioning and hardware-in-the-loop.
• Lead software parts of FAT and SAT, and commission tools at customer sites in Taiwan, including cleanroom work.
• Troubleshoot field issues, carry out root-cause analysis (8D, FMEA) and deliver fixes under tight fab uptime targets.

Ideal Profile:

• Master's or Bachelor's Degree in Automation Control, Electrical Engineering, Mechatronics, Computer Engineering, or a related discipline.
• 5+ years of hands-on PLC software development for industrial machines, including at least 2 full projects from design to commissioning.
• Experience in PLC programming with Beckhoff TwinCAT or Rockwell
• Strong knowledge of IEC 61131-3 (Structured Text).
• Solid experience working with C#, .NET is a great plus as well.
• Experience with HMI development, EtherCAT, OPC UA, and industrial automation.
• Familiarity with PackML, machine diagnostics, and recipe management is an advantage.
• Good problem-solving skills and ability to work in an international team.
• Fluent English communication skills.