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Packaging Engineer- Bump Interconnect

Volantis · Volantis is a semiconductor manufacturing company that designs and manufactures AI chips optimized for high-performance computing needs.

Hybrid Remote/SF Bay Area/Austin/Boston (Remote)1-10 employeesPosted 3 months ago
Undisclosedraised 50 days agoled by Alumni Ventures, Unpopular Ventures, 7percent Ventures

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<p>We’re seeking an experienced engineer to lead bump interconnect development for advanced semiconductor devices&nbsp; (2.5D/3D/chiplet/fan-out).&nbsp;</p> <p>&nbsp;</p> <p>This role spans ubump and C4 bump metallurgy, RDL design and</p> <p>plating, chip-side and interposer capture pad design rules, OSAT engagement, reliability,</p> <p>failure analysis,&nbsp;and cross-functional support through package and system productization.</p> <p>&nbsp;</p> <p><strong>Core Responsibilities</strong></p> <ul> <li>Own end-to-end bump interconnect development for both ubump (micro-bump) and C4</li> </ul> <p>processes, including bump formation, and reflow for use with mass reflow, TCB, and LAB chip</p> <p>attach for high-performance semiconductor packages.</p> <ul> <li>Define and own bump metallurgy stacks for ubump (e.g., Cu pillar/SnAg) and C4 (e.g., SAC alloys)</li> </ul> <p>interconnects, including UBM selection and pad finish specifications for both chip-side and</p> <p>interposer capture pads.</p> <ul> <li>Develop and own design rules for bump interconnects including pitch, bump diameter, standoff</li> </ul> <p>height, keep-outs, and land pad geometry for both the chip side and interposer or substrate</p> <p>capture pads.</p> <ul> <li>Lead RDL (redistribution layer) process development including electroplating of Cu RDL traces,</li> </ul> <p>via fills, and pad finishes; define RDL design rules for line/space, via diameter, and layer stack-up</p> <p>to meet electrical and reliability requirements.</p> <ul> <li>Collaborate with OSATs and bumping foundries to qualify ubump and C4 bumping processes,</li> </ul> <p>drive design rule alignment, and manage process transfers into production.</p> <p>&nbsp;</p> <ul> <li>Evaluate and mitigate bump interconnect assembly risks including non-wet opens, voiding, head-</li> </ul> <p>in-pillow, intermetallic growth, and joint fatigue failures across both ubump and C4 interconnect&nbsp;types.</p> <ul> <li>Perform root cause analysis of assembly and reliability failures using cross-sectioning, SEM,</li> </ul> <p>CSAM, and other failure analysis techniques.</p> <ul> <li>Support reliability qualification including thermal cycling, drop, mechanical shock, and power cycling.</li> </ul> <ul> <li>Work cross-functionally with design, reliability, thermal, and manufacturing teams to ensure</li> </ul> <p>robust package performance from concept through high-volume production.</p> <p>&nbsp;</p> <p><strong>Required Technical Skills</strong></p> <ul> <li>Strong experience in bump interconnect processes including ubump (Cu pillar, micro-bump) and</li> </ul> <p>C4 bumping for semiconductor devices.</p> <p>&nbsp;</p> <ul> <li>Deep understanding of bumping metallurgy including UBM stacks, solder alloy systems (SnAg),</li> </ul> <p>intermetallic compound (IMC) formation and growth kinetics, and their impact on joint reliability.</p> <ul> <li>Experience with RDL plating processes including Cu electroplating, photoresist patterning, seed</li> </ul> <p>layer deposition, and associated design rules for line/space, via geometry, and pad stack.</p> <ul> <li>Understanding of thermo-mechanical behavior in bump interconnect assemblies including CTE</li> </ul> <p>mismatch, warpage, solder joint fatigue, and IMC-driven reliability risks for both ubump and C4</p> <p>configurations.</p> <ul> <li>Hands-on experience with failure analysis and reliability testing (cross-sections, SEM, CSAM,</li> </ul> <p>thermal cycling).</p> <ul> <li>Ability to work with OSATs and suppliers to develop and transfer assembly processes into</li> </ul> <p>production.</p> <ul> <li>Strong problem-solving skills with ability to debug yield and reliability issues in manufacturing</li> </ul> <p>environments.</p> <p>&nbsp;</p> <p><strong>Preferred / Differentiating Skills</strong></p> <ul> <li>Experience with III-V packaging, photonics packaging, and precision chip attach.</li> <li>Experience with advanced packaging technologies including 2.5D interposers, 3D stacking,</li> </ul> <p>chiplets, and CoWoS-like architectures.</p> <ul> <li>Familiarity with fine-pitch micro-bump and hybrid bonding approaches.</li> <li>Experience integrating high-power or high-TDP devices with tight warpage and thermal</li> </ul> <p>constraints.</p> <ul> <li>Exposure to thermo-mechanical modeling or collaboration with simulation teams for warpage</li> </ul> <p>and reliability prediction.</p> <ul> <li>Understanding of system-level interactions (warpage, second-level interconnect reliability).</li> <li>Deep expertise in bump metallurgy fundamentals including UBM stack design (Ti/Cu, etc.), solder</li> </ul> <p>alloy selection, wetting behavior, and the influence of plating chemistry and process conditions</p> <p>on bump morphology and composition.</p> <ul> <li>Fundamental knowledge of intermetallic compound (IMC) formation, growth kinetics, and phase</li> </ul> <p>behavior in Cu/Sn, Ni/Sn, and Au/Sn systems; understanding of how IMC thickness, morphology,</p> <p>and composition affect joint strength, electromigration resistance, and long-term reliability.</p> <p><br><br></p> <p><strong>Education &amp; Experience:</strong></p> <p>Industry experience in semiconductor packaging with strong emphasis on bump interconnect</p> <p>processes, RDL development, and productization.</p>
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