Principal Product Engineer

Lightmatter is leading the revolution in AI data center infrastructure, enabling the next giant leaps in human progress. The company invented the world’s first 3D-stacked photonics engine, Passage™, capable of connecting thousands to millions of processors at the speed of light in extreme-scale data centers for the most advanced AI and HPC workloads. Lightmatter raised $400 million in its Series D round, reaching a valuation of $4.4 billion. We will continue to accelerate the development of data center photonics and grow every department at Lightmatter! If you're passionate about tackling complex challenges, making an impact, and being an expert in your craft, join our team of brilliant scientists, engineers, and accomplished industry leaders. Lightmatter is (re)inventing the future of computing with light! The Product Engineer role is pivotal to Lightmatter’s mission, sitting at the center of product delivery and operational excellence. This position offers a unique opportunity for end-to-end ownership, where you will define the product engineering landscape from the ground up and drive the strategic direction for our hardware portfolio. You will collaborate with cross-functional teams (design, foundry, packaging, test, validation, reliability) to optimize manufacturing flows, improve yield and quality, and reduce costs. The role's focus areas include: optimizing Yield & Quality, implementing DFx principles, and managing the product from initial silicon to high-volume manufacturing (HVM). The core responsibilities are specifically centered on optimizing manufacturing flows, yield Improvement, and Test Point Optimization. Strategic Ownership: Own the product's success by managing yield and quality indicators from first silicon to high-volume manufacturing (HVM). Manufacturing Excellence: Define manufacturing and test strategies, including DFT implementation, test hardware specs, and test program creation. Yield & Cost Optimization: Drive continuous improvement in quality, yield, and cost by reducing test time, eliminating test sockets, closing test holes (DPM reduction), and increasing yield through root cause analysis with cross-functional teams (design, fab, packaging). Hands on leadership: Debug test, yield, and power/performance issues. Guiding Light: Lead multi-disciplinary teams (Design, Foundry, Packaging, Supply Chain, etc.) to resolve product issues and continuously improve team tools and methods. Qualifications Master’s in Computer Science,Electrical Engineering, Physics, Material Science or a related field A minimum of 5+ years experience in semiconductor industry as a product engineer, with a cumulative of 12 years of relative industry experience Experience developing DFT strategy Experience developing test plans Familiarity with advanced packaging flows Familiarity with ATE Test area equipment and methodology Experience partnering with OSATs to develop manufacturing test flows for CMOS or Optical transceiver products Excellent communication skills with ability to present complex technical information clearly and concisely Demonstrated ability to influence senior company leadership and partner with vendors and customers Familiarity with statistical analysis & data acquisition tools such as JMP, Snowflake Preferred: Experience partnering with a OSAT to develop manufacturing test flows for Co-Packaged Optics technology Programming or scripting: Python, C, Java, Ruby, SQL, or shell scripting The salary range for this position reflects two distinct internal levels. The lower half of the range applies to candidates meeting the core requirements, while the upper half is reserved for those who bring the additional specialized experience or extensive years of experience required for our senior-level designation. We offer competitive compensation. The base salary range for this role determined based on location, experience, educational background, and market data. Salary Range: total compensation goes beyond base salary, it