Characterization and Electrical Performance of Glass Diplexer Modules
Citation
Woychik, C., Lauffer, J., Pollard, S., Parmar, R., Gaige, M., Wilson, W., Carey, J., Neely, M., Ling, F., & Chen, L. (2019). Characterization and Electrical Performance of Glass Diplexer Modules. International Symposium on Microelectronics, 2019(1), 1-8.
Keywords
- Glass interposer
- Through glass via (TGV)
- Diplexer module
- Semi-additive plating (SAP)
- Ajinomoto Buildup Film (ABF)
- Quality factor (Q)
- RF loss
- Form factor
- Capacitors and inductors
- Electrical characterization
Brief
This article describes a novel process for manufacturing a glass diplexer module using conventional circuit board processes, highlighting the advantages of glass interposers in achieving superior RF filter performance with lower loss and smaller form factor.
Summary
This article presents a novel approach to building diplexer modules using a glass substrate with through glass vias (TGVs). Here are the key takeaways:
- Glass interposers are shown to offer superior performance compared to silicon and ceramic alternatives in RF filter applications, particularly for achieving high-quality factors (Q) in inductors essential for low insertion loss and high adjacent band attenuation. This is especially important for 5G technology that utilizes a wider frequency range.
- The article outlines a detailed process of manufacturing a glass diplexer module using existing circuit board processes adapted for glass substrates. The researchers highlight copper plating as their preferred method for creating robust TGVs in a manufacturing setting over electrically conductive adhesives (ECAs).
- A significant part of the process involves using a semi-additive plating (SAP) technique to create fine copper circuitry on both sides of the glass substrate. An Ajinomoto Buildup Film (ABF) is then laminated to both sides, filling the vias and ensuring a smooth and flat surface for subsequent copper plating.
- The researchers successfully fabricated a diplexer module using the described process with 100µm diameter vias on a 300µm thick glass substrate. The article includes a description of the diplexer test vehicle and presents electrical data measurements confirming the viability of their approach.
- Measured data from fabricated diplexer modules demonstrate a close correlation with simulated results, indicating the potential for real-world applications. The authors also emphasize the importance of meticulous handling of glass substrates throughout the manufacturing process to prevent defects and achieve acceptable yields.