Panel Level Packaging (PLP)

Panel-Level Packaging Advanced Photoresist Coating Solutions for Semiconductor Panels

With advanced packaging technology shifting from wafer-based processing to oversized panel manufacturing formats, conventional spin coating can no longer deliver even photoresist coverage on expansive rectangular substrates. Ultrasonic spray coating technology delivers an accurate, mass-producible deposition method to form evenly distributed photoresist thin films on panel packaging substrates, applicable to fan-out packaging, redistribution layer fabrication and other sophisticated semiconductor packaging workflows.

Ultrasonic spray technology lays down regulated, thin photoresist layers covering entire panel surfaces, individual packaging units, vias, circuit traces and uneven surface structures while cutting raw material consumption significantly. Switching from spin coating to contact-free ultrasonic spraying helps fabrication facilities cut photoresist consumption, stabilize coating homogeneity, and sustain stable photolithography outcomes on oversized panels—where consistent coating thickness and process reproducibility stand as core production demands.

Photoresist Deposition for Panel-Level Packaging

Panel packaging relies on precise photoresist layering over large substrates integrated with hundreds to thousands of separate packaging units. Ultrasonic spraying delivers consistent photoresist coverage atop redistribution layers, bonding pads, dielectric surfaces and pre-patterned structures, laying a solid foundation for precise lithography operations in high-end packaging manufacturing.

Compared with traditional coating techniques, the ultrasonic spraying process maintains steady coating thickness across the full panel surface and suppresses common defects such as liquid accumulation, streaks and edge unevenness. This strength is particularly prominent for large rectangular panels, as spin coating typically generates massive material loss and uneven film thickness distribution on such formats.

Fan-Out Packaging and Redistribution Layer Fabrication

Photoresist serves as a key patterning material for redistribution layers, vias and interconnection frameworks in fan-out panel packaging. Ultrasonic spray coating realizes controllable material deposition on panels with intricate surface geometries, ensuring intact film layers over both protruding and recessed microstructures.

Low-speed, mild atomized mist output from ultrasonic spray heads achieves full uniform coverage without overflowing tiny microstructures. This stable photoresist layer maintains steady performance throughout exposure, development, metal deposition and etching follow-up procedures.

Coating for Oversized Substrates

Panel packaging substrates feature far larger dimensions than traditional silicon wafers, making photoresist uniformity and material utilization efficiency critical production indicators. Ultrasonic coating equipment adopts precise motion control and accurate liquid feeding structures, delivering repeatable coating effects for large rectangular panels with high material transfer rates.

This technical route allows manufacturers to seamlessly expand lab-scale coating parameters to mass production lines, while retaining stable film thickness, robust coating adhesion and lower chemical raw material usage.

Integration with Advanced Packaging Production Lines

Panel packaging ultrasonic coating equipment can be customized to meet cleanroom standards and seamlessly incorporated into full advanced packaging production chains. The equipment supports mixed photoresist solvent formulations and dielectric-compatible coating liquids, with customizable process parameters matching diverse customer substrates and panel specifications.

Covering laboratory research, pilot trial runs and fully automated inline mass production, ultrasonic coating platforms offer flexible performance to meet continuously upgraded advanced packaging demands, including fan-out packaging, heterogeneous integration, chiplet assembly and cutting-edge microelectronic component manufacturing.

Core Technical Merits

• Homogeneous photoresist layering across large rectangular panel substrates
• Expandable alternative to spin coating for panel packaging production
• Elevated material transfer efficiency to cut photoresist and solvent waste
  Adjustable coating thickness adaptable to redistribution layer structures, vias, bonding pads and packaging units
• Mild low-speed ultrasonic atomization to avoid liquid pooling and streaking defects
• Strong coating adhesion and outstanding repeatability on complex uneven panel surfaces
• Fully compliant with cleanroom manufacturing standards
• Flexible scalability from lab process testing to automated mass production lines

Core Ultrasonic Spray Atomization Technology

Ultrasonic spray coating equipment centers on proprietary ultrasonic atomization spray heads. The devices utilize high-frequency acoustic vibration to generate soft atomized mist with tightly controlled droplet sizes. Unlike pressure-driven atomization methods, ultrasonic atomization produces gentle, evenly dispersed spray streams that resist nozzle blockages.

The narrow droplet size distribution and low-impact spray flow enable precise photoresist deposition on large-area substrates. This helps advanced packaging manufacturers secure uniform film quality, slash raw material waste and guarantee stable, reproducible production processes.

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