Processing Through Glass Via (TGV) Interposers for Advanced Packaging
Citation
Woychik, Charles, John Lauffer, David Bajkowski, Michael Gaige, Robert Edwards, Gordon Benninger, and William Wilson. "Processing Through Glass Via (TGV) Interposers for Advanced Packaging." International Symposium on Microelectronics, 2018.
Keywords
- Through Glass Vias (TGVs)
- Glass Interposer
- Semi-Additive Plating (SAP)
- Electrically Conductive Adhesives (ECAs)
- Copper Plating
- Integrated Passive Devices (IPDs)
- High-Density Interconnect (HDI)
Brief
This article describes how to create Through Glass Vias (TGVs) on glass interposers using semi-additive plating and copper plating techniques, enabling advanced electronic packaging for applications like integrated passive devices.
Summary
The article focuses on the use of glass as a substrate material for advanced packaging applications, specifically highlighting its advantages in creating Through Glass Vias (TGVs) for high-density interconnects.
Here's a summary of the key findings:
- Advantages of Glass Interposers: Compared to organic materials, glass offers superior properties such as high resistivity, low loss, smooth surface for fine circuitry, and a CTE that can be engineered to match silicon, eliminating the need for underfill.
- Methods for Creating TGVs: The article explores three approaches:
- Filling vias with isotropic Electrically Conductive Adhesives (ECAs).
- Superconformal plating to completely fill the vias with copper.
- Conformal plating to create a conductive pathway along the via walls.
- ECA Approach: Various ECA formulations were tested for their ability to fill glass vias. ECA-B emerged as the most promising candidate after optimizing printing parameters like pressure and speed.
- Copper Plating Approach:
- Research at Binghamton University demonstrated superconformal plating for completely filling TGVs with copper, achieving high aspect ratios (AR) while minimizing surface plating thickness.
- They used additives like TNBT and MTT to control plating rates and achieve bottom-up filling.
- This method allowed them to fill vias with ARs of 6 and 10, significantly reducing the plating time.
- Conformal Plating Approach: The authors developed a process for conformal copper plating to create TGVs with an AR of 3 and 6. This method is compatible with wafers up to 200mm in diameter.
- Glass Interposer Applications:
- The article describes the creation of a glass interposer with double-sided circuitry and TGVs, highlighting the use of Semi-Additive Plating (SAP) for fine-line circuitry.
- It also explains the fabrication of an Integrated Passive Device (IPD) module using a glass interposer with copper TGVs, illustrating the integration of inductors and capacitors.
Overall, the article presents glass as a viable and advantageous material for future electronics packaging, particularly for applications requiring high-density interconnects and miniaturization.