Semiconductor Test Engineer

About Fractile Fractile was founded in 2022 on the bet that, eventually, the world’s most capable AI systems would be limited in their impact by the time taken to produce useful outputs. We bet everything on the logical conclusion: that the only way to truly unlock this latent value, to make speed viable at scale, was to radically re-invent the hardware that we run our frontier AI models on. Ever since, we have been building chips and systems that tackle this problem: how to efficiently generate output at thousands of tokens per second, while handling the complexity and capacity challenges of operating large models at very long contexts. The workloads that push to the limits of the current frontier are already transformational; it is the technical and economic limits on inference speed that are constraining progress. The defining work of the 21st century will be marked by the engine of inference delivering immense and diffuse chains of intellectual inquiry, in drug discovery, in software engineering, in materials discovery, in any field where progress is driven by deep reasoning and intelligence to resolve complex problems. Summary We are seeking an experienced Semiconductor Test Engineer to lead the development and deployment of manufacturing test solutions for next-generation AI accelerator devices. This role spans the full silicon lifecycle from first silicon bring-up through high-volume production, with responsibility for defining test strategy, developing ATE test content, debugging complex silicon issues, and optimizing yield, coverage, and test cost. The ideal candidate will bring deep expertise in DFT methodologies, high-speed interface testing, and advanced CMOS manufacturing, and will work closely with design, DFT, packaging, and manufacturing partners to ensure robust, scalable production of high-performance compute silicon. Key Responsibilities • Develop and maintain ATE test programs for an AI accelerator chip targeting high-volume manufacturing. • Implement manufacturing test content for advanced CMOS designs including high-speed logic, SRAM, DRAM, and high speed IO blocks. • Develop and debug structural and functional test content such as scan/ATPG, LBIST, MBIST, JTAG, and HSIO tests. • Bring up first silicon on ATE, including pattern debug, tester correlation, shmooing, and corner analysis. • Support testing of high-speed interfaces such as PCIe Gen6 and multi-GHz LPDDR, including at-speed tests and margining features. • Execute silicon characterization and failure analysis to identify yield limiters and defect mechanisms. • Optimize test coverage, test time, and cost while maintaining manufacturing robustness. • Work with DFT and design teams to improve testability and close coverage gaps. • Collaborate with OSATs and external partners on test program execution and debug. • Support advanced packaging test flows, including die-to-die interconnect testing and package-level thermal considerations. • Contribute to documentation of test programs, debug procedures, and manufacturing release materials. • • Support qualification, reliability testing, and high-volume manufacturing ramp. Required Qualifications • 5+ years of hands-on semiconductor test engineering experience. • Strong experience developing ATE test programs (Advantest 93K, Teradyne, or equivalent). • Solid understanding of DFT methodologies (scan, ATPG, MBIST, LBIST) and memory test techniques. • Experience debugging silicon issues at the tester and correlating failures to design or process causes. • Familiarity with advanced CMOS nodes and production test challenges. • Ability to work effectively in a cross-functional engineering environment. Preferred Qualifications • Experience testing AI accelerators, GPUs, networking ASICs, or other high-performance compute ICs. • Experience with PCIe Gen5/Gen6, LPDDR4/5/6, or other high-speed interfaces. • Exposure to advanced packaging, chiplets, or multi-die test flows. • Experience improving yield, reducing test time, or optimizing cost in high-volume manufacturing. How we work • Ownership and execution: you will have full agency to drive your work forward • Rapid iteration: we all work directly with top leadership to move from idea to hardware on ambitious timelines • Full-stack engagement: hardware, software, silicon, and modelling teams all work closely together to create a product with generational impact • Optimistic and pragmatic: we possess the will to win, and to do the hard work to get us there • Team player mentality: the mission is bigger than any of us, and we have the curiosity and technical focus to see the best idea shipped, no matter who’s it is What We Offer • Competitive salary: A competitive salary reflective of your experience and the specialist nature of the role. • Equity & Ownership: meaningful equity so everyone shares in the value creation • Benefits: Private Medical, Dental and Vision, Contributory Pension, 25 Days holiday plus bank holidays and Life/Critical Illness Insurance. • Diverse & fun office: we believe the hardest problems get solved by the broadest range of minds. We are committed to Equal Employment Opportunity through attracting and retaining a diverse team and building an inclusive environment. Fractile is seeking to increase the clock speed of global progress, one chip at a time. We’ve recently raised $220M from investors including Founders Fund and Accel and our most important work lies ahead. Join us! Export controls Our work involves technologies subject to UK, US and other international export control regulations. Certain roles may require additional eligibility checks to ensure compliance with applicable law. We'll be transparent about this throughout the hiring process.