Flexible Circuit Board Package Embedded With Multi-Stack Dies

2020 ◽  
Author(s):  
Nobuki Ueta ◽  
Shunsuke Sato ◽  
Masakazu Sato ◽  
Yoshio Nakao ◽  
Joshua Magnuson ◽  
...  
Keyword(s):  
Hearing Aids ◽  
High Reliability ◽  
Polyimide Film ◽  
High Density ◽  
Circuit Board ◽  
Electrical Measurements ◽  
Test Vehicle ◽  
One Step ◽  
Lamination Process ◽  
High Density Packaging

Abstract Miniaturization of electronics modules is always required for various medical applications including wearable technology, such as hearing aids, and implantable devices. Many types of high-density packaging technologies, such as package-on-package, bare-die stack, flex folded package and Through Si Via (TSV) technologies, have been proposed and used to fulfill the request. Among them, embedded die technology is one of the promising technologies to realize miniaturization and high-density packaging. We have developed WABE™ (wafer and board level device embedded) technology for embedding dies into multilayer flexible printed circuit (FPC) boards. The WABE package is comprised of thin dies (85 μm thickness), multi-layer polyimide, adhesive films and conductive paste. The dies are sandwiched by polyimide films with Cu circuits (FPCs). The conductive paste provides electrical connections between the layers as well as the layer and embedded die. First, each FPC layer is fabricated individually, and via holes are filled with conductive paste, and the dies are mounted on certain layers. Then, all layers undergo a one-step co-lamination process, and they are pressed to cure the adhesive material and conductive paste at the same time. This WABE technology has enabled multiple dies to be embedded by the one-step lamination process. Even if multiple dies are embedded, the footprint of a package can be reduced drastically by embedding multiple dies vertically in stacks. This paper describes the details of the results of fabricating a test vehicle with six embedded dies (three-dies in two stacks side-by-side). The fabricated test vehicle had 14 copper layers with less than 0.9 mm thickness. This paper also reports the results of various reliability testing on the package. These results were obtained by electrical measurements of daisy chain patterns formed between some of the layers. The fabricated test vehicle showed high reliability based on the results of a moisture and heat test and heat-shock test. These results show that the WABE technology to embed multiple dies vertically in polyimide film is one of the most promising packaging technologies to significantly miniaturize electronic circuits such as medical electronics.

Development of High Reliability Via on IVH (VONI) for High Density Interconnect Circuit Boards

2007 ◽  
Vol 4 (2) ◽  
pp. 78-85
Author(s):  
Jong-Won Park ◽  
Yun-Seok Hwang ◽  
Il-Kyoon Jeun ◽  
Da-Hee Joung ◽  
Myung-Gun Chong ◽  
...  
Keyword(s):  
Water Adsorption ◽  
High Reliability ◽  
Chemical Properties ◽  
High Density ◽  
Circuit Boards ◽  
Shock Testing ◽  
Via Holes ◽  
Via Hole ◽  
The Relationship ◽  
High Density Packaging

Via on interstitial via hole (VONI) technique is a complex set of technologies for blind and buried vias in traditional sequential lamination cycles with external layers, and micro via holes (MVH) for true high-density packaging. However, when VONI is repeatedly subjected to thermal stress, the interstitial via hole (IVH) in its structure often creates problems such as IVH barrel cracks, and layer-layer delamination. To solve VONI's reliability problems, such as IVH barrel crack and layer-layer delamination, the authors have investigated the relationship between the CTE difference and the effect of moisture. Through using different types of plugging inks, it was clearly indicated that delamination was related to the chemical properties of the plugging inks. For example delamination was dominated by the inks property of water adsorption, which induced vapor pressure when it undergoes thermal shock testing. The authors have solved the delamination problem by reducing the ratio of water adsorption in the plugging ink.

Evaluation of die to organic laminate to PCB interconnects up to 50GHz

2019 ◽  
Vol 2019 (1) ◽  
pp. 000223-000227
Author(s):  
Selaka Bulumulla ◽  
Koushik Ramachandran
Keyword(s):  
High Frequency ◽  
Printed Circuit Board ◽  
Substrate Material ◽  
Circuit Board ◽  
Test Vehicle ◽  
Ceramic Substrates ◽  
High Frequencies ◽  
Multiple Levels ◽  
High Frequency Performance ◽  
High Density Packaging

Abstract Ceramic substrates have traditionally been used in RF and microwave packaging applications because of the electrical properties at high frequencies. However, there is significant interest in using organic laminates due to its tighter wiring ground rules for high density packaging and lower cost of fabrication. The high frequency performance of interconnection from die to PCB using an organic packaging substrate has not yet been studied in detail. In this work, the interconnect performance of die to organic laminate to PCB up to 50 GHz was modeled and characterized using a test vehicle assembly. The test vehicle was specifically designed with test pads to characterize the interconnect performance at multiple levels of interconnection. A comparison study using a ceramic package substrate was also carried out. The modeling and hardware testing results from this study showed −3dB bandwidth of more than 50GHz for printed circuit board (PCB) to organic laminate and a bandwidth of 40GHz for the die to organic laminate to PCB interconnection. The results from this study showed that the organic laminate demonstrated a high frequency performance comparable to that of the ceramic substrate, which makes it suitable as a packaging substrate material for high frequency applications.

Development of High Permeability Core Materials for Embeddable Inductors in Flexible Organic Substrates

2003 ◽  
Vol 769 ◽  
Author(s):  
C. K. Liu ◽  
P. L. Cheng ◽  
S. Y. Y. Leung ◽  
T. W. Law ◽  
D. C. C. Lam
Keyword(s):  
Low Temperature ◽  
Sol Gel ◽  
Circuit Board ◽  
Organic Substrates ◽  
Circuit Boards ◽  
High Permeability ◽  
Electrical Measurements ◽  
Different Temperatures ◽  
Spiral Inductors ◽  
Ceramic Tape

AbstractCapacitors, resistors and inductors are surface mounted components on circuit boards, which occupy up to 70% of the circuit board area. For selected applications, these passives are packaged inside green ceramic tape substrates and sintered at temperatures over 700°C in a co-fired process. These high temperature processes are incompatible with organic substrates, and low temperature processes are needed if passives are to be embedded into organic substrates. A new high permeability dual-phase Nickel Zinc Ferrite (DP NZF) core fabricated using a low temperature sol-gel route was developed for use in embedded inductors in organic substrates. Crystalline NZF powder was added to the sol-gel precursor of NZF. The solution was deposited onto the substrates as thin films and heat-treated at different temperatures. The changes in the microstructures were characterized using XRD and SEM. Results showed that addition of NZF powder induced low temperature transformation of the sol-gel NZF phase to high permeability phase at 250°C, which is approximately 350°C lower than transformation temperature for pure NZF sol gel films. Electrical measurements of DP NZF cored two-layered spiral inductors indicated that the inductance increased by three times compared to inductors without the DP NZF cores. From microstructural observations, the increase is correlated with the changes in microstructural connectivity of the powder phase.

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