Printing carrier tray processing

Printed circuit board (PCB) trays are specialized support devices used in semiconductor packaging and testing. They are primarily used to support and transport PCBs, ensuring positioning accuracy and structural stability during chip mounting, bonding, and testing processes. Widely applicable to the large-scale packaging production of integrated circuits, power semiconductors, and other devices, their processing quality directly impacts semiconductor packaging yield and production efficiency.

The processing of PCB trays places specific requirements on raw materials, balancing rigidity, wear resistance, and dimensional stability. Mainstream materials include fiberglass reinforced epoxy resin boards, engineering plastics (such as PEEK and POM), and aluminum alloy profiles. Fiberglass reinforced epoxy resin boards are suitable for high-precision packaging scenarios, possessing excellent insulation and deformation resistance; aluminum alloy profiles are suitable for supporting large-size PCBs, offering better heat dissipation; and engineering plastic trays, with their lightweight and corrosion-resistant characteristics, meet the transport needs of flexible production lines.

The processing flow encompasses four core stages: blank preparation, precision machining, surface treatment, and assembly testing. The entire process must be completed in a cleanroom to prevent dust and impurities from affecting subsequent semiconductor packaging processes. In the blank preparation stage, CNC cutting machines cut the boards to preset dimensions and chamfering removes edge burrs to prevent debris generation during processing. Precision machining is a crucial step in pallet manufacturing. High-speed CNC milling machines and CNC machining centers are used to mill the pallet's positioning holes, support grooves, guide grooves, and other structures. Positioning holes must precisely match the positioning pins of the printed circuit board (PCB), with hole tolerances controlled to a minimum. The flatness of the support grooves must be strictly calibrated to prevent tilting of the PCB after placement, which would affect chip mounting accuracy. Some high-precision pallets also require vacuum adsorption holes to fix the PCB using negative pressure, further improving stability during transport.

Two key points must be carefully controlled during processing: first, dimensional consistency—critical dimensional deviations within the same batch of pallets must be kept within a minimal range to ensure compatibility with production line equipment; second, stress relief—after processing, the boards undergo aging treatment, such as constant temperature placement or annealing, to eliminate residual stress generated during processing and prevent deformation after long-term use.

The surface treatment process requires selecting appropriate processes based on the material properties. Plastic trays are typically sandblasted to improve surface abrasion resistance and remove machining marks; aluminum alloy trays undergo anodizing to form a dense oxide film, enhancing corrosion resistance and insulation; fiberglass epoxy resin trays require grinding and polishing to ensure a smooth load-bearing surface and prevent scratches on the printed circuit board (PCB) surface.

During the assembly and inspection phase, locating pins, guide blocks, and other accessories must be installed in place. Then, a coordinate measuring machine (CMM) is used to inspect key indicators such as hole accuracy and flatness of the tray. Simultaneously, simulated load tests are conducted to verify the structural stability of the tray under load. Trays that pass inspection undergo anti-static treatment, either by spraying an anti-static coating or embedding anti-static fibers, to prevent electrostatic damage to semiconductor devices.

As semiconductor packaging technology advances towards high density and miniaturization, PCB tray processing is upgrading towards customization and high precision. Dedicated load-bearing structures can be designed and manufactured according to the needs of different PCB specifications. Furthermore, the integration of digital processing technology enables precise control of processing parameters, contributing to the efficient operation of semiconductor packaging production lines.