Principal SW Engineer

Cohu is a global supplier of semiconductor test and automation equipment. In this role you will build and sustain software that controls complex electro-mechanical test handlers used in high-volume semiconductor manufacturing.

Design and develop proprietary Windows desktop application and framework software for control machines, automation systems, and complex electro-mechanical platforms – including motion controllers, I/O systems, sensors, machine vision systems, robotics, and barcode readers. This role spans full lifecycle development—from architecture and design through integration, deployment, and customer support—focused on uptime, safety, and predictable behavior.

This position is ideal for engineers who enjoy building large software systems that interact with sophisticated industrial equipment.

• Design, develop, test, and integrate machine control software using C++ and C# in a Visual Studio environment.
• Develop automation software using object-oriented design principles and software design patterns.
• Integrate motion controllers, I/O systems, machine vision, robotics, sensors, barcode readers, and other industrial devices through vendor-provided Windows APIs and SDKs.
• Drive system architecture, interface definitions, and software design reviews; establish patterns that scale across product variants.
• Own customer escalation response: troubleshoot issues using logs, instrumentation, and on-equipment debugging; deliver corrective actions and prevention plans.
• Partner with Manufacturing and Field Service to resolve production-line and installed-base issues, restore system uptime, and improve reliability.
• Build verification strategies that push failure detection upstream (simulation, automated system tests, regression suites) and reduce re-occurrence.
• Interface with customers and cross-functional teams (EE/ME/Test/Apps) to align requirements, integration plans, and release readiness.
• Mentor engineers through code reviews, design feedback, and technical coaching.

• Bachelor’s or Master’s degree in Computer Engineering, Software Engineering, Computer Science, Electrical Engineering, or a related field.
• 15+ years of professional software engineering experience, including substantial work on automation, machine control, or complex electro-mechanical systems.
• Expert C/C++ skills with object-oriented design (OOD) and design patterns; ability to write maintainable, testable, production-quality code.
• Strong experience developing on Windows desktop applications using Visual Studio; familiarity with C# for tooling, diagnostics, or UI is preferred.
• Experience developing multithreaded software and event-driven software.
• Experience integrating external hardware using Windows APIs, SDKs, or communication libraries.
• Proficiency with version control and collaborative development workflows (Git preferred): code reviews, branching strategies, and disciplined change management.
• Demonstrated ability to troubleshoot and resolve field issues, including root-cause analysis and implementing corrective/preventive actions.
• Strong written and verbal communication skills; comfortable presenting designs and status to technical and non-technical stakeholders.

• Semiconductor equipment, test handlers, ATE integration, or factory automation environments.
• Comparable experience in industrial automation, robotics, medical devices, or high-volume product engineering with electro-mechanical systems.
• Preferred / Additional Skills (Highly Beneficial for Test Handler Software)
• State machine development, event-driven software architecture, machine sequencing, hardware integration through vendor API, motion control APIs, machine vision integration.
• Hardware/software integration experience (MCU/SoC peripherals, serial buses, timing/latency considerations) and familiarity with common interfaces (RS-232/RS-485, USB, Ethernet, TCP/IP, CAN, I2C, SPI).
• UI development experience for operator/service tools (WPF, Win Forms, or Qt); ability to build effective diagnostics and recovery workflows.
• Build and release tooling: CI/CD pipelines (e.g.,…