With the number of connected-devices increasing tremendously, communication data rates are projected to be at least 10–100X in the 5G/mm-wave (MMW) technology - much higher than the existing 4G LTE connections.[1], [2] To catch up with the trend, novel packaging technology in the MMW frequency range is required, which will address fundamental MMW technical challenges such as high dielectric loss, degradation of quality factors in passives, increased parasitic, dramatically-enhanced electromagnetic interference, and the reduced radiation efficiency of antenna arrays.
State-of-the-art approaches being pursued include organic-core substrates that have a low dielectric constant (Dk) and low dissipation factor (Df) such as fluorine based or liquid-crystal polymer (LCP) substrates in order to achieve enhanced antenna performance and low signal dissipations. These organic-based substrate technologies, however, can neither miniaturize packages nor handle precision signal routings that enable high density packages. To address these challenges, attention is focused on Fan-Out Wafer Level Package (FOWLP) technologies, like eWLB, InFO, and SWIFT, where integrated circuits (ICs) are embedded in epoxy molding compound. [3]–[6]
Recently, glass-panel embedding (GPE) technology is emerging as an ideal packaging methodology that enables superior performance along with small form factor, ultra-low-loss, high density, ultra-short interconnects, and low cost. [7] These benefits stem from the advantages of using glass which has excellent properties such as ultra-smooth surface for precision redistribution layer (RDL), exceptional dimensional stability for panel-scalability and tailorability of CTE that allow direct board-attach for improved system performance. In addition, utilizing the epoxy molding compounds as encapsulation material allows the GPE package to be thinner and more robust package with small farm factor. Molding of glass cavity panels also helps with the handling of ultra-thin glass which is seen as a bottleneck towards glass based packaging solutions in production. These facilitates enhanced throughput by allowing more cavity cut outs (more coupons) per panel.
This paper presents the first demonstration of ultra-thin GPE with sheet type epoxy molding compound (SMC) for 5G/mm-wave applications. First part of this paper discusses the process-flow used in glass-panel embedding with laminated SMC, including chip placement in glass cavities, lamination of SMC, and the reliability of the package architecture. This paper reports on such a demonstration in 60 μm glass substrates with 40 μm thickness SMC. The second part of this paper focuses on low-loss interconnects for 5G/mm-wave applications and presents the process development of signal routings such as transmission lines and microvias in RDLs as well as through-package vias (TPVs) with via-in-via process. The results suggest that the ultra-thin GPE architecture is a promising packaging technology solution for a variety of applications including high-frequency communications and high-performance computing.
[1]
Chong Ser Choong,et al.
Comprehensive Investigation of Die Shift in Compression Molding Process for 12 Inch Fan-Out Wafer Level Packaging
,
2016,
2016 IEEE 66th Electronic Components and Technology Conference (ECTC).
[2]
Rao Tummala,et al.
Nanostructured miniaturized artificial magnetic conductors (AMC) for high-performance antennas in 5G, IoT, and smart skin applications
,
2017,
2017 IEEE 17th International Conference on Nanotechnology (IEEE-NANO).
[3]
Yasuhito Fujii,et al.
Warpage Control of Liquid Molding Compound for Fan-Out Wafer Level Packaging
,
2018,
2018 IEEE 68th Electronic Components and Technology Conference (ECTC).
[4]
Rao Tummala,et al.
2.5D Glass Panel Embedded (GPE) Packages with Better I/O Density, Performance, Cost and Reliability than Current Silicon Interposers and High-Density Fan-Out Packages
,
2018,
2018 IEEE 68th Electronic Components and Technology Conference (ECTC).
[5]
Curtis Zwenger,et al.
Chip Stackable, Ultra-thin, High-Flexibility 3D FOWLP (3D SWIFT® Technology) for Hetero-Integrated Advanced 3D WL-SiP
,
2018,
2018 IEEE 68th Electronic Components and Technology Conference (ECTC).
[6]
Manos M. Tentzeris,et al.
Leading-Edge and Ultra-Thin 3D Glass-Polymer 5G Modules with Seamless Antenna-to-Transceiver Signal Transmissions
,
2018,
2018 IEEE 68th Electronic Components and Technology Conference (ECTC).
[7]
Fuhan Liu,et al.
Design and demonstration of Glass Panel Embedding for 3D System Packages for heterogeneous integration applications
,
2018
.
[8]
Holger Maune,et al.
Attenuation of high Frequency Signals in Structured Metallization on Glass: Comparing Different Metallization Techniques with 24 GHz, 77 GHz and 100 GHz Structures
,
2019,
2019 IEEE 69th Electronic Components and Technology Conference (ECTC).
[9]
Alexander Tomkins,et al.
Compact 60 GHz Phased-Array Antennas With Enhanced Radiation Properties in Flip-Chip BGA Packages
,
2019,
IEEE Transactions on Antennas and Propagation.