Cu CMP Dishing in High Density Cu Pad for Fine Pitch Wafer-to-Wafer (W2W) Hybrid Bonding

Cu CMP Dishing in High Density Cu Pad for Fine Pitch Wafer-to-Wafer (W2W) Hybrid Bonding

2021 IEEE 23rd Electronics Packaging Technology Conference (EPTC)

10.1109/EPTC53413.2021.9663921

http://dx.doi.org/10.1109/eptc53413.2021.9663921

Hongmiao Ji, King-Jien Chui

05 January 2022

Ji, H., & Chui, K.-J. (2021). Cu CMP Dishing in High Density Cu Pad for Fine Pitch Wafer-to-Wafer (W2W) Hybrid Bonding. 2021 IEEE 23rd Electronics Packaging Technology Conference (EPTC). https://doi.org/10.1109/eptc53413.2021.9663921

Wafer-to-wafer (W2W) hybrid bonding is a key process technology in advance heterogeneous integration. Electrical connections between top surface metal lines of different wafers (e.g. memory, logic) can be made by means of wafer-to-wafer stacking to enable reduced latency and data-bandwidth between different wafers.Successful implementation of this key process technology requires good bonding interfaces with controlled surface roughness and precise control of dishing/protrusion on both the dielectric and Cu pad surfaces.This paper characterizes the chemical mechanical planarization (CMP) process on hybrid bonding Cu surfaces for different Cu pad designs. It provides the guidelines in design of Cu pad/spacing, line/spacing pattern to achieve desired bonding surfaces after CMP polishing. This simplifies the layout design and reduces the process tuning cost.

Publisher Copyright

This research / project is supported by the A*STAR - Programmatic
Grant Reference no. : A1892b0026

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Institute of Microelectronics