C2H4 reductive plasma treatment on copper surface for copper bonding
This study investigated the effects of C _2 H _4 plasma treatment on a Cu surface and its influence on the quality of Cu–to–Cu bonding. C _2 H _4 plasma is applied to enhance Cu bonding by producing reactive hydrogen for effective oxide removal and activation, while forming a protective carbon layer...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | Materials Research Express |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/2053-1591/addc3c |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | This study investigated the effects of C _2 H _4 plasma treatment on a Cu surface and its influence on the quality of Cu–to–Cu bonding. C _2 H _4 plasma is applied to enhance Cu bonding by producing reactive hydrogen for effective oxide removal and activation, while forming a protective carbon layer at lower temperatures with simpler processing than forming gas. An 8-inch Si wafer with a 700 nm thick SiO _2 layer was used as the substrate, onto which 50 nm Ti and 1 μm Cu layers were deposited by DC magnetron sputtering. The Cu surface was treated with C _2 H _4 plasma for varying durations (10 ∼ 90 s) to modify its surface characteristics. XPS (x-ray photoelectron spectroscopy) analysis showed that plasma treatment reduced the surface oxides and contaminants, with a noticeable increase in Cu _2 O. AFM (atomic force microscopy) measurements indicated that the plasma treatment decreased the surface roughness by over 40%, with the roughness decreasing as the plasma-treatment time increased. Cu-to-Cu bonding was performed at 260 °C, followed by annealing at 200 °C. A bonding quality was assessed using SAT (scanning acoustic tomography), FE-SEM (field emission scanning electron microscopy), and TEM (transmission electron microscopy), revealing that the plasma-treated sample exhibited fewer voids and a diffused Cu interface, suggesting improved bonding compared to the non-plasma-treated sample. The results indicate that C _2 H _4 plasma treatment enhances the Cu surface, leading to improved Cu-to-Cu bonding quality. |
|---|---|
| ISSN: | 2053-1591 |