Dec 8, 2015 | Atlanta, GA
Georgia Tech proposed glass packaging five years ago as the next generation packaging platform technology after plastic packaging starting in 1970s, ceramic starting in 80s and organic build-up starting in 1990s, because of its superior electrical properties such as low electrical loss, thermal expansion matching Si, smooth surface finish, no-moisture absorption, and availability in ultra-thin and large form factors without having to grind. Georgia Tech identified and addressed three fundamental limitations of glass that included low thermal conductivity, through-silicon-via (TSV)-like through-via formation at fine pitch at low cost, and mechanical brittleness.
Georgia Tech and its partners developed high throughput small through-package-vias (TPV) holes and metallization processes as well as low-cost RDLs with 2-5 micron wiring leading to 20-40 micron I/O pitch on both sides of thin glass. With these basic research demonstrations, Georgia Tech began to pioneer a new 3D system package architecture, interconnecting chips with shortest interconnect lengths and potentially unlimited I/O density enabled by TSV-like Cu TPVs but at system level.
As a result of these co-developments, substrate companies such as Shinko in Japan and Unimicron in Taiwan are beginning to be ready for prototypes and low volume production. Shinko and Unimicron demonstrated manufacturing readiness of 100 micron thin glass panels by demonstrating first set of panels ranging in size from 250mm to 510mm with 2 micron RDL wiring technology. In addition, Georgia Tech and its partner Amkor demonstrated glass package assembly both with reflow for RF and TCB for digital applications. While Georgia Tech’s research team is focusing on 2 micron RDL with 3-8 micron micro vias at 20 micron pitch, Corning and Asahi Glass demonstrated manufacturing readiness of glass with through-vias.
In contrast, organic interposers are being developed with 200 micron core thickness, 80 micron pitch through vias, 5-6 micron RDL wiring with 20 micron diameter micro vias. The Georgia Tech glass interposers achieve the same I/O pitch as silicon interposers, but on much larger panels for lower cost, and much higher electrical performance enabled by the ultra-low loss of glass compared to ultra-high loss of silicon.
Georgia Tech developed a variety of 3D glass-based digital, photonic and RF and modules.
Digital Modules: Both single-chip application processor module and 2.5D logic-memory multichip modules, with superior attributes over Si interposers for cost and performance and over organic interposers in ground rules and I/O pitch.
Photonic Modules: The Georgia Tech team in partnership with TE Connectivity and Ciena demonstrated 3D glass photonic-electronic modules with both transmit and receive capability in multi- and single-mode, enabling ultra-high bandwidth for cloud computing and automotive applications.
RF Applications: Georgia Tech and its partner TDK and Qualcomm demonstrated RF modules, both WLAN and LTE modules, with superior attributes over the current ceramic and organic modules. Georgia Tech’s glass-based 3D RF modules are 2X smaller in X-Y form factor and 2X smaller in thickness than organic modules. The glass modules offer high-Q LC integration with better than 5% tolerance compared to ceramic modules. Georgia Tech’s glass RF R&D includes superior diplexers at < 0.5 dB insertion loss, inductors with high-Q factors from lower-loss substrates and dielectrics, and ultra-thin 3D IPDs with shortest interconnection length between components. Georgia Tech’s 3D Package concept integrates, components with precision lithography, very high-Q factor, thin EMI shielding and improved thermal management.
Power Modules: The Georgia Tech team is developing power modules with both capacitors with capacitance density of 1 µF/mm² and inductors with inductance density of 1000nH/mm².
These unparalleled R&D demonstrations are setting the stage for glass as the next device and system packaging platform technology. The current co-developing global partners contributing to these R&D and manufacturing-readiness are many, and include:
- Materials: Ajinomoto, Asashi Glass, Brewer Science, Corning Glass, HC Stark, Mitsubishi Gas Chemical, Schott, and TOK
- Tools: Applied Materials, Asahi Glass, Atotech, Coherent, Disco, ESI, K&S, Mitsubishi Electric, MKS, Orbotech, Suss, Tango, Ushio, Veeco, and XYZtec
- Substrates: Shinko, NGK/NTK, and Unimicron
- Assembly: Amkor, ASE, JCET, Namics and QualiTau
- Components: AVX, GigaLane, TDK Epcos and TI
- IC & System: Ciena, Global Foundries, Intel, Qualcomm, TE Connectivity and TSMC
For more information about Georgia Tech’s glass packaging technology, please contact Prof. Rao Tummala at email@example.com.