Package Reliability Engineer

Company: Celestial AI
Location: Santa Clara
Posted on: February 14, 2026

Job Description:

Job Description Job Description About Celestial AI As Generative AI continues to advance, the performance drivers for data center infrastructure are shifting from systems-on-chip (SOCs) to systems of chips. In the era of Accelerated Computing, data center bottlenecks are no longer limited to compute performance, but rather the system's interconnect bandwidth, memory bandwidth, and memory capacity. Celestial AI's Photonic Fabric™ is the next-generation interconnect technology that delivers a tenfold increase in performance and energy efficiency compared to competing solutions. The Photonic Fabric™ is available to our customers in multiple technology offerings, including optical interface chiplets, optical interposers, and Optical Multi-chip Interconnect Bridges (OMIB). This allows customers to easily incorporate high bandwidth, low power, and low latency optical interfaces into their AI accelerators and GPUs. The technology is fully compatible with both protocol and physical layers, including standard 2.5D packaging processes. This seamless integration enables XPUs to utilize optical interconnects for both compute-to-compute and compute-to-memory fabrics, achieving bandwidths in the tens of terabits per second with nanosecond latencies. This innovation empowers hyperscalers to enhance the efficiency and cost-effectiveness of AI processing by optimizing the XPUs required for training and inference, while significantly reducing the TCO2 impact. To bolster customer collaborations, Celestial AI is developing a Photonic Fabric ecosystem consisting of tier-1 partnerships that include custom silicon/ASIC design, system integrators, HBM memory, assembly, and packaging suppliers. ABOUT THE ROLE We are seeking an experienced Package Reliability Engineer with expertise in 2.5D/3D advanced packaging. The ideal candidate will have a strong background in physics of failure, materials science, and experience working closely with OSATs to drive package reliability improvements. This role requires collaboration with external assembly and test partners, internal design, process, and failure analysis teams, and suppliers to ensure the reliability and manufacturability of cutting-edge semiconductor packages. ESSENTIAL DUTIES AND RESPONSIBILITIES Reliability Analysis & Risk Assessment: Conduct physics of failure (PoF)-based reliability modeling for 2.5D/3D advanced packaging. Assess package reliability risks from thermal, mechanical, and electrical stressors. Define and execute stress test plans (e.g., thermal cycling, humidity, electromigration) to validate package robustness. OSAT Management & Collaboration: Work closely with OSAT partners to drive package reliability improvements, process optimizations, and yield enhancements. Define reliability requirements, review test methodologies, and ensure OSAT compliance with JEDEC and industry standards. Monitor and evaluate OSAT performance in executing reliability qualifications and failure analysis. Support supplier audits and technical reviews to assess manufacturing capabilities and reliability processes. Material Characterization & Selection: Evaluate and select materials (substrates, dielectrics, adhesives, underfills) for optimal reliability. Analyze CTE mismatches, warpage, delamination, and interfacial adhesion issues. Work with material suppliers and OSATs to qualify new materials for advanced packaging applications. Failure Analysis & Root Cause Identification: Lead failure mode analysis (FMEA), model-based problem solving (MBPS) and determine root causes of package failures using techniques such as FIB, X-ray, SEM, and TEM. Identify and mitigate interfacial failures, cracking, voiding, electromigration, and stress-induced damage. Drive OSATs and internal teams to implement corrective and preventive actions (CAPA). Process & Design Collaboration: Work cross-functionally with internal design, process, and manufacturing teams to define assembly test vehicles and optimize package architectures. Develop and refine design guidelines, process improvements, and reliability best practices. Stay up to date with industry standards (JEDEC, IPC, IEEE, etc.) and implement best practices in package reliability. QUALIFICATIONS Education: Master's or Ph.D. in Materials Science, Mechanical Engineering, Electrical Engineering, Applied Physics, or a related field. Experience: 5-10 years of hands-on experience in 2.5D/3D advanced packaging reliability. Technical Expertise: Deep understanding of physics of failure (PoF) methodologies for package reliability. Strong knowledge of materials science, particularly in interconnects, substrates, and interfaces. Proficiency in stress modeling tools (ANSYS, Abaqus, COMSOL, etc.) for thermo-mechanical analysis. Experience with failure analysis techniques such as C-SAM, X-ray CT, SEM, TEM, FIB, and EBSD. OSAT Collaboration Experience: Proven track record of working with and driving OSAT partners for package reliability, yield, and continuous quality improvements. Experience managing OSAT qualifications, failure analysis, and corrective actions. Familiarity with supplier engagement, reliability testing at OSATs, and package process flows. Industry Knowledge: Familiarity with JEDEC, IPC, IEEE, and MIL-STD reliability standards. Soft Skills: Strong analytical, problem-solving, and cross-functional collaboration skills. PREFERRED QUALIFICATIONS Experience in heterogeneous integration, fan-out packaging, chiplet architectures. Knowledge of electrical reliability mechanisms (e.g., electromigration, time-dependent dielectric breakdown). Expertise in AI-driven reliability modeling or machine learning for failure prediction. LOCATION : Santa Clara, CA For California Location: As an early stage start up, we offer an extremely attractive total compensation package inclusive of competitive base salary, bonus and a generous grant of our valuable early-stage equity. The target base salary for this role is approximately $185,000.00 - $225,000.00. The base salary offered may be slightly higher or lower than the target base salary, based on the final scope as determined by the depth of the experience and skills demonstrated by candidate in the interviews. We offer great benefits (health, vision, dental and life insurance), collaborative and continuous learning work environment, where you will get a chance to work with smart and dedicated people engaged in developing the next generation architecture for high performance computing. Celestial AI Inc. is proud to be an equal opportunity workplace and is an affirmative action employer. LI-Onsite

Keywords: Celestial AI, Oakland , Package Reliability Engineer, Engineering , Santa Clara, California