Direct copper metallization on TGV (Thru-Glass-Via) for high performance glass substrate
Citation
Onitake, S., Inoue, K., & Takayama, M. (2017). Direct copper metallization on TGV (Thru-Glass-Via) for high performance glass substrate. 2017 International Symposium on Microelectronics, 1-4. International Microelectronics Assembly and Packaging Society (IMAPS). https://doi.org/10.4071/isom-2017-wp52_085
Keywords
- Glass substrate
- TGV (Through-Glass Via)
- Copper metallization
- Adhesion strength
- Wet plating process
- High-frequency applications
- IoT (Internet of Things)
Brief
This article presents a new wet plating process for direct copper metallization on glass substrates with through-glass vias (TGVs), eliminating the need for adhesion layers and enabling cost-effective manufacturing of high-performance electronic devices.
Summary
This article from the 2017 International Symposium on Microelectronics, authored by Shigeo Onitake, Kotoku Inoue, and Masatoshi Takayama, proposes a novel method for direct copper plating on glass substrates for use in high-frequency electronic devices.
The main argument is that glass, with its superior properties like low conductivity and dielectric loss, is ideal for next-generation communication devices exceeding 20 GHz signal frequency.
Here are some key findings from the article:
- Traditional materials like plastic and ceramics are reaching their performance limits, while silicon interposers, though effective, are expensive and have scalability limitations.
- Glass offers numerous advantages over silicon:
- Cost-effectiveness: Glass is significantly cheaper than silicon, making it a more viable option for large-scale production.
- Superior properties: Glass boasts high insulation, low dielectric loss, better thermal and chemical resistance, high transparency, excellent surface smoothness, and a thermal expansion coefficient similar to silicon.
- Scalability: Glass substrates can be easily scaled to larger areas, unlike silicon wafers, enhancing productivity and throughput.
- Direct copper plating on glass is challenging due to adhesion issues. Existing methods using seed layers or sol-gel techniques are complex, expensive, and often impractical for mass production.
- The authors present a new wet plating process that eliminates the need for intermediary layers like nickel, chromium, or titanium.
- This method has been proven successful, achieving a direct copper-to-glass adhesion strength of 0.42 kN/m.
- The process ensures uniform copper film formation on large glass substrates and within through-holes.
- Importantly, the surface smoothness of the glass is retained even after plating, ensuring high-quality circuit fabrication.
- The article provides evidence of successful circuit formation with 75μm line/space dimensions using this method.
The authors conclude that this novel wet plating technique holds significant promise for manufacturing next-generation electronic devices that require 3D glass substrates.