Motoshi Ono

Design, fabrication and characterization of low-cost glass interposers with fine-pitch through-package-vias

This paper demonstrates thin glass interposers with fine pitch through package vias (TPV) as a low cost and high I/O substrate for 3D integration. Interposers for packaging of ULK and 3D-ICs need to support large numbers of die to die interconnections with I/O pitch below 50 μm. Current organic substrates are limited by CTE mismatch, wiring density, and poor dimensional stability. Wafer based silicon interposers can achieve high I/Os at fine pitch, but are limited by high cost. Glass is an ideal interposer material due to its insulating property, large panel availability and CTE match to silicon. The main focus of this work is on a) electrical and mechanical design, b) TPV and fine line formation and c) integration process and electrical characterization of thin glass interposers. This work for the first time demonstrates high throughput formation of 30 μm pitch TPVs in ultrathin glass using a parallel laser process. An integration process was demonstrated for glass interposer with polymer build-up layers on both sides. The glass interposer had stable electrical properties up to 20GHz and low insertion loss of less than 0.15dB was measured for TPVs at 9GHz.

Development of Through Glass Via (TGV) formation technology using electrical discharging for 2.5/3D integrated packaging

This study explored Through Glass Via (TGV) Formation Technology by using Focused Electrical Discharging Method for alkali-fee glass which has well matched CTE with Si. 2.5D/3D Packaging has presently attracted lots of attention, an interposer is recognized as one of key materials, and its development of new fine pitch, high dense, and low cost interposer are accelerated. Glass is expected as one of candidates as a substrate material of future interposer substrate. This study demonstrates TGV formation showed capabilities of fine pitch and high dense, and TGV formation for standard thick glass aiming varied applications for packaging such as MEMS, Optical device, and RF device. This study discussed further challenges related to metalization technique and carrying methods for glass interposer. Necessary future development and subjects were pointed out.

Ultra-miniaturized and surface-mountable glass-based 3D IPAC packages for RF modules

This paper demonstrates ultra-miniaturized RF passive components integrated on thin glass substrate with small Through Package Vias (TPVs) to realize 3D Integrated Passive and Actives Component (IPAC) concept. Miniaturization is achieved through; a) ultra-thin glass, b) low-loss thin dielectrics and c) small TPVs. Inductors, capacitors and low pass filters functioning in the frequency range of 0.8 GHz to 5.4 GHz were modeled and fabricated between thin dielectric layers on 100 μm thin glass, and then assembled on PCB through BGA interconnections. The simulated results corroborated well with measured results, providing guidelines for RF module fabrication.

Optical Burst Switching Node with Sub-millisecond Granularity Equipped with Agile Tunable Wavelength Converter and Waveguide Amplifier

An optical switching node with sub-millisecond granularity is demonstrated. The node is equipped with shared wavelength converter for contention resolution with microsecond tuning speed and compact gain block for loss compensation based on erbium-doped waveguide.

Multi-hop Transmission with Wavelength Conversion for Collision Resolution in PLZT Matrix Switch-based Optical Burst Switching Node Prototype

Multi-hop cascadibility of a PLZT matrix switch-based optical burst switching node prototype is presented. Using a 50 km recirculating loop setup and a 4times4 matrix switch, more than 10 hop transparency at 10 Gb/s was achieved. Hop-by-hop wavelength conversion for contention resolution and signal reshaping effect was confirmed.

Over 19-dB Amplification at Whole C-band of 8-Channels Er-doped Waveguide Array with 15 × 15 mm 2 Foot Print

Gain characteristics of 8-channels Er-doped bismuthate waveguide array are measured under bidirectional pumping at 1480 nm. Over 19-dB gain with flatness of 2 dB at whole C-band has been obtained using a 25-cm long waveguide.

TGV technology for Glass interposer

This study explored glass microfabrication technologies for TGV (Through Glass Via) formation can be applied interposer substrate of 3D packaging. Two TGV formation methods were studied and compared such as optical approach using Excimer laser and electrical approach using focused electrical discharging. Demonstration of laser microfabrication showed the result of 40um pitch of TGVs which is able to be fine pitch solution. And demonstration of focused electrical discharging method showed the result of ultrafast TGV process with 75um pitch. In this study, we compared characteristic of both technologies and pointed necessary future development for glass interposer application.

Application of DuPont photopolymer films to automotive holographic display

Automotive holographic head-up display (HUD) systems employing DuPont holographic photopolymer films are presented. Holographic materials for automotive application are exposed to severe environmental conditions and are required high performance. This paper describes the improvement of DuPont photopolymer films for the automotive use, critical technical issues such as optical design, external color and stray light. The holographic HUD combiner embedded in a windshield of an automobile has peculiar problems called external color. Diffraction light from holographic combiner makes its external color tone stimulative. We have introduced RGB three color recording and color simulation in order to improve the external color. A moderate external color tone was realized by the optimization in terms of wavelengths and diffraction efficiencies of the combiner hologram. The stray light called flare arises from a reflection by glass surface of windshield. We have developed two techniques to avoid the flare. First is a diffuser type trap beam guard hologram which reduces the intensity of the flare. Second is the optimization of the design of hologram so that the incident direction of flare is lower than the horizon line. As an example of automotive display a stand-alone type holographic HUD system attached on the dashboard of an automobile is demonstrated, which provides useful driving information such as route guidance. The display has a very simple optical system that consists of only a holographic combiner and a vacuum fluorescent display. Its thin body is only 35 mm high and does not obstruct drivers view. The display gives high contrast and wide image.

Development of through glass vias (TGV) and through quartz vias (TQV) for advanced packaging

Through via formation is definitely the key for coming the advanced packaging which includes heterogeneous integration and high speed wireless communication. Glass and fused silica are well known as a great candidate for a core material for high frequency application as a result of high bulk resistance and lower dielectric loss. One of the important subjects in order to use through glass vias (TGV) and through quartz vias (TQV) substrates is “handling” due to a brittleness of glass. However, the mechanical strength of TGV substrate and its evaluation approach is not enough reported so far. This study shows the latest TGV/TQV formation and the mechanical strength of glass as well as methodological investigation.

Development of High Frequency Device Using Glass or Fused Silica with 3D Integration

Glass and fused silica are promising material used as a substrate for RF components because of good electrical properties such as low permittivity and low dielectric loss tangent. Whats more, glass and fused silica have higher bulk resistance because of insulation material, and superior stabilities against environmental changes as packaging level. This study explores, firstly a methodology and measurement results of high frequency characteristic of glass and fused silica up to 110 GHz, secondly, microfabrication technologies for glass and fused silica and those demonstration work especially about through via formation and metallization in prospect of 3D integrated RF packaging. Lastly, future development subjects related to RF components using glass or fused silica are discussed.