Customer background

A major semiconductor packaging house in Penang, Malaysia, required a reliable, high-throughput wafer-level dispensing solution to support mass production of Fan-Out Wafer-Level Packaging (FOWLP). Their production roadmap demanded an in‑fab system that could run underfill, coating, flux spray, and dam & fill processes with strict cleanliness, thermal stability, and anti-warp control for mixed 8‑inch and 12‑inch wafer lots.

Technical challenge 

FOWLP underfill at wafer level exposes delicate redistribution layers (RDLs) and bump structures to particulate and thermal stress. Key production constraints included:

• Maintaining Class 10 clean dispensing to avoid contamination on exposed wafer surfaces.
• Controlling wafer warpage during preheat and dispense cycles (target anti-warp ±3 mm) to preserve nozzle standoff and capillary flow behavior.
• Delivering sub-10 µm positional accuracy and repeatable dispense volumes across full 8/12‑inch wafer formats.
• Integrating with factory MES/AMHS for traceability and unmanned operation.

Mingseal solution 

Mingseal deployed the SS101 — the first domestically developed wafer-level dispensing cell qualified for FOWLP underfill mass production. System highlights and process adaptations for the Penang line included:

• Class 10 cleanroom-compatible enclosure with automated FOUP and open cassette handling to support both 12‑inch and 8‑inch wafers without cross‑contamination risk.
• Robotic wafer transfer and high-precision aligner for sub-10 µm placement accuracy; code scanning and MES logging provide per‑wafer traceability for recipes, images, and event history.
• Zoned preheating and closed‑loop thermal control to bring wafers to optimal dispensing temperature while minimizing thermal gradients that cause warpage.
• Dual GS600SWA/SWB dispensing stations within the SS101 cell to run underfill, conformal coating, flux spray, and dam & fill operations in a configurable sequence with ±10 µm positional control.
• Mechanical anti‑warp fixture and process tuning capable of compensating wafer deformation up to ±3 mm, preserving nozzle standoff and preventing tailing or void formation during capillary underfill.
• Post‑dispense heat dissipation station to control cool‑down rate and protect bump integrity before FOUP return, enabling consistent cure profiles and reduced stress.

Production outcomes

• Successful FOWLP mass production: The SS101 cell enabled the customer’s transition from pilot to full-rate production for wafer-level underfill and associated processes, supporting both 8‑inch and 12‑inch wafer programs.
• Improved process stability: Active anti‑warp control and precise thermal management reduced underfill voiding and edge overflow, improving first-pass yield and lowering scrap.
• High precision and throughput: Dual dispensing stations and automated wafer handling preserved cycle time targets while maintaining sub‑10 µm positioning and repeatable dispense volumes across large wafer batches.
• Seamless fab integration: SEMI‑compliant communication and AMHS/MES connectivity allowed lights‑out operation, full traceability, and rapid fault diagnosis through logged process data and imaging.

Conclusion 

As the first domestically produced wafer-level dispensing system validated for FOWLP underfill in Penang, the SS101 delivered a production‑grade solution combining cleanroom compatibility, precise thermal and anti‑warp controls, and full factory integration. Mingseal continues to support on‑site process optimization, DOE-based recipe tuning, and MES integration to help fabs scale FOWLP production with predictable yield and throughput. Contact Mingseal to arrange a pilot run or qualification plan tailored to your wafer sizes and process mix.