access icon free Process enabling highly accurate die position for fan-out package applications

© The Institution of Engineering and Technology
Received 02/02/2017, Published 11/05/2017
Errata or comment

A new process that can improve die shift issue in process utilising back-sided under bump metallurgy (UBM) via a self-alignment effect for fan-out package applications is proposed. The die and the pad of the substrate are spontaneously aligned and the degree of accuracy is very high after reflow. For the experiment, two kinds of UBM pads were prepared on glass dies and the SAC305 solder was formed on the copper pads of an frame retardent (FR)-based substrate. The die shift value was from 20 to 50 μm after pick-and-placement. After reflow, the maximum die shift value was <1 μm. An initially misaligned die with a large shift was aligned with a high degree of accuracy during reflow due to the surface tension of the molten solder. The proposed process improves the die shift issue in the fabrication of fan-out wafer-level packaging and the active die embedded substrate.

Inspec keywords: position control; wafer level packaging

Other keywords: fan out wafer level packaging; SAC305 solder; die shift issue; die shift value; glass dies; process enabling highly accurate die position; back-sided under bump metallurgy; self-alignment effect; FR-4-based substrate; active die embedded substrate; fan-out package applications; UBM pads; copper pads

Subjects: Semiconductor integrated circuits; Product packaging

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