Jong-Min Yook

30 Gbps High-Speed Characterization and Channel Performance of Coaxial Through Silicon Via

Coaxial through silicon via (TSV) technique allows reduction of high frequency loss due to conductivity in silicon substrate and flexibility in impedance by controlling the ratio of shield to center radii. For the first time, we measured and analyzed the high-speed channel performance of coaxial TSV. This letter presents the measurement results of the fabricated test vehicle in S-parameter and eye-diagram. The eye-diagram measurement results prove that coaxial TSV is capable of supporting signal transmission up to bit rate of 30 Gbps. The equivalent circuit model is suggested and experimentally verified by S-parameter comparison. Furthermore, the superiority of coaxial TSV over conventional TSV is confirmed by comparison of S-parameter results from equivalent circuit model simulation.

High density and low-cost silicon interposer using thin-film and organic lamination processes

In this paper, a new low-cost silicon interposer technology is introduced. Organic lamination processes are used for multi-layer signals and through via-holes are made by adjusting UV laser drilling. It is possible to make a 80 μm minimum through via using laser drilling. The fabricated interposer has an only 230 μm thickness and it has more than 6 metal layers including thin film metal. In this interposer, thin film spiral inductors and MIM capacitors can be integrated in the silicon substrate. For low-loss and high isolation, a TOLV (Through Organic Lining Via) and COLV (Coaxial Lining Via) can be made. The fabricated coaxial via has very low loss, 0.07 dB at 10 GHz, and high isolation properties for a wide frequency range, more than 40 dB at 0~40 GHz.

Suspended Spiral Inductor and Band-Pass Filter on Thick Anodized Aluminum Oxide

We make suspended inductors and 2.45 GHz BPFs on the selectively anodized aluminum. The thick anodized alumina is used as the supporting dielectric and it is easily removed by using chemical wet-etching. The thickness of anodized alumina is 80 mum and the depth of the total air-cavity is 200 mum. The fabricated inductor over an air cavity has a 25% greater Q factor and 21% higher inductance at 2 GHz compared to an inductor on anodized aluminum. The 2.45 GHz BPF adjusting the suspended inductors has 2.8 dB of insertion loss with a narrow bandwidth.

High performance IPDs (Integrated passive devices) and TGV (Through glass via) interposer technology using the photosensitive glass

In this paper, a new TGV interposer technology is introduced in which the through via could be made by using a photolithography and chemical wet-etching. To make fine and accuracy via-holes, etching properties of the glass are studied in various UV-exposure times. It is possible to make TGVs from 60 μm to 20 μm with a 4:1 aspect ratio. Based on the TGV process, a high-aspect-ratio metal is made and high-Q spiral inductors can be realized by using the technology. The fabricated inductor has a very thick signal height more than 80 μm and its Q factor is more than 30 at 2 GHz. To demonstrate the process technology, a 0.9 GHz LPF, which is can be used for the RF front-end of the GSM band, is designed and fabricated using the inductor. The realized LPF has very low insertion loss of only 0.31 dB at the pass band, and this value is an improvement of more than 32% compared with the normal LPF.

High-Q trenched spiral inductors and low-loss low pass filters using through silicon via processes

In this study, a high-aspect-ratio metal is made by the standard through silicon via (TSV) process, and high-Q trenched spiral inductors can be realized by using the technology. The fabricated inductor has 60 µm signal height and its Q factor is more than 30 at 2 GHz. As a result, the Q factor of the trench inductor depends on signal spacing rather than signal width. The peak Q factor is maximized when the signal spacing is increased. To demonstrate the process technology, a 0.9 GHz low pass filter (LPF), which is can be used for the RF front-end of the GSM band, is designed and fabricated using the inductor. The realized LPF has very low insertion loss of only 0.355 dB at the pass band, and this value is an improvement of more than 28% compared with the normal LPF.

High-quality solenoid inductor using dielectric film for multichip modules

For multilayer applications, we made high-quality and easily fabricated solenoid inductors using a dielectric material (UPILEX-S, UBE Industries, Tokyo, Japan). These inductors fabricated on UPILEX-S had a larger Q factor compared to that of a spiral inductor fabricated on a silicon or GaAs substrate. Furthermore, it is possible to stack these inductors to make multichip modules using solder or gold stud bumps. From the measurement, solenoid inductors fabricated on 50-/spl mu/m-thick film showed very high Q factors and stable inductances.

Air-Cavity Transmission Lines on Anodized Aluminum for High-Performance RF Modules

In this study, we form air-cavity transmission lines on anodized aluminum substrates. The fabricated transmission lines are microstrip, grounded CPW, and microshield structures. Thick anodized alumina is used as the post of the suspending structures, and it is realized very easily using selective chemical wet-etching. The insertion losses of the fabricated transmission lines on the anodized aluminum are within a range of 0.2-0.26 dB/mm, and they improve greatly after realizing air-cavity structures to 0.043-0.076 dB/mm at 40 GHz.

Spiral Inductors Using Polymer-Core Conductors

We made thick spiral inductors using a polymer-core conductor. The proposed fabrication process to make the polymer-core conductor is very easy and cost effective compared with other radio frequency microelectromechanical systems processes. SU-8 photoresist was used as the core. The fabricated spiral inductors on a high resistivity silicon, 2500 Omega have a very high Q factor of more than 40 at 2 GHz.

High-Performance RF Inductors and Capacitors Using the Reverse Trench Structure of Silicon

We propose new passive device structures using deep silicon trenches. High-aspect-ratio reverse trench structures coated with copper can be used to make signal lines of the spiral inductor, and a deep trench around the MIM capacitor can be used as a signal isolation wall after back-side thinning. A laminated organic is used to fill the trench. It is possible to make a 10:1 ratio metal pattern maximally, and all signal lines are fixed and isolated due to the laminated organic. Though the spiral inductor is realized on lossy silicon, its Q-factor is higher than 40 at 2 GHz. The fabricated 0.9 GHz LPF adjusting the reverse trench process has only 0.5 dB insertion loss with a very small size.

An X-band high power amplifier module package using selectively anodized aluminum substrate

In this paper, we made a high power amplifier module package using a selectively anodized aluminum substrate for the X-band radar T/R modules. The proposed solution of package is based on thick anodized aluminum oxide (Al2O3) layers and power chips mounted on aluminum for an effective heat sink. The fabricated high power amplifier module has a maximum output power of 39.49 dBm and maximum gain of 32 dB over 9-10 GHz frequency band. This package method can be further contributed to decreasing cost, reducing module size and managing thermal problem for the microwave high power T/R modules.