Low-Loss, High-Linearity RF Interposers Enabled by Through Glass Vias

Shah, Umer; Liljeholm, Jessica; Campion, James; Ebefors, Thorbjörn; Oberhammer, Joachim

doi:10.1109/lmwc.2018.2869285

Cited by 25 publications

(8 citation statements)

References 11 publications

(15 reference statements)

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“…Being inexpensive, transparent, electrically insulating, chemically inert, biocompatible, of high mechanical stiffness, and reusable, glass is a natural choice for the fabrication of interposing layers [30]. For example, it was recently shown that the use of TGVs can lead to low-loss and high-linearity radio frequency interposers [31]. Moreover, the properties of glass are strongly tunable.…”

Section: Introductionmentioning

confidence: 99%

Nanocrystalline diamond-glass platform for the development of three-dimensional micro- and nanodevices

Janssens

Vázquez-Cortés

Giussani

et al. 2019

Diamond and Related Materials

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Low-cost and robust platforms are key for the development of next-generation 3D micro-and nanodevices. To fabricate such platforms, nanocrystalline diamond (NCD) is a highly appealing material due to its biocompatibility, robustness, and mechanical, electrical, electrochemical, and optical properties, while glass substrates with through vias are ideal interposers for 3D integration due to the excellent properties of glass. However, developing devices that are comprised of NCD films and through glass vias (TGVs) has rarely been attempted due to a lack of effective process strategies. In this work, a low-cost process -free of photolithography and transfer-printing -for fabricating arrays of TGVs that are sealed with suspended portions of an ultra-thin NCD film on one side is presented. These highly transparent structures may serve as a platform for the development of microwells for single-cell culture and analysis, 3D integrated devices such as microelectrodes, and quantum technologies. The process is demonstrated by fabricating TGVs that are sealed with an NCD film of thickness 175 nm and diameter 60 µm. The technology described can be extended by replacing NCD with silicon nitride or silicon carbide, allowing for the development of complex heterogenous structures on the small scale.

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Section: Introductionmentioning

confidence: 99%

Nanocrystalline diamond-glass platform for the development of three-dimensional micro- and nanodevices

Janssens

Vázquez-Cortés

Giussani

et al. 2019

Diamond and Related Materials

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“…Another disadvantage can be found in nonlinearity of conventional TSVs through the formation of a metal-oxidesemiconductor capacitor. Hence, silicon substrates are very unfavorable for high-linearity and low-insertion loss RF applications [20].…”

Section: Introductionmentioning

confidence: 99%

RF Glass Technology Is Going Mainstream: Review and Future Applications

Chaloun¹,

Brandl²,

Ambrosius³

et al. 2023

IEEE J. Microw.

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Driven by the increasing demand for high-throughput communication links and high-resolution radar sensors, the development of future wireless systems pushes at ever greater operating frequencies. By analogy, high-performance computing (HPC) systems with high-bandwidth I/Os have become a mainstream solution to address multi Gbit/s data rates. Heterogeneous integration technologies play a vital role here in enhancing the performance and functional density, along with reducing the size and costs of such RF systems. In line with this trend, many passive components, which have once been monolithically integrated, are now implemented on ceramic or polymer-based packages. Besides these long-established material and process technologies, considerable efforts have also recently been devoted to the development of RF components on glass and glass-ceramics. Spurred by their low dielectric losses, extremely smooth surfaces, and excellent dimensional stability, glass technologies are emerging as a promising alternative for high-volume and high-performance RF applications. In this article, relevant glass materials and key enabling technologies are reviewed and put into context with well-established RF substrate technologies. Another focus is set on the latest glass-based packaging and interposer solutions ranging from MHz-to-THz frequencies. To showcase the development activities and practical accomplishments of the RF glass technology, also a large variety of key components is presented. Finally, the paper concludes by discussing future research and development directions of RF glass devices.INDEX TERMS MTT 70th Anniversary Special Issue, glass technology, dielectrics, packaging, interposer, system-on-package, interconnects, filters, antennas, antenna-in-package, millimeter wave (mm-wave).

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“…As an alternative to resolve these challenges, glass substrate with through glass vias (TGVs) has recently been used for the packaging substrate or interposers for high-frequency applications [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Glass, as a substrate material, is emerging because of its low electrical loss, ability to form fine-pitch metal lines and spaces, machineability to create micro-size TGVs, high dimensional stability, a closely matched coefficient of thermal expansion (CTE) to silicon dies, and productivity in thin and large panels.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Substrate-Integrated Waveguide Using Micromachining of Photoetchable Glass Substrate for 5G Millimeter-Wave Applications

et al. 2023

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A millimeter-wave substrate-integrated waveguide (SIW) was firstly demonstrated using the micromachining of photoetchable glass (PEG) for 5G applications. A PEG substrate was used as a dielectric material of the SIW, and its photoetchable properties were used to fabricate through glass via (TGV) holes. Instead of the conventional metallic through glass via (TGV) array structures that are typically used for the SIW, two continuous empty TGV holes with metallized sidewalls connecting the top metal layer to the bottom ground plane were used as waveguide walls. The proposed TGV walls were fabricated by using optical exposure, heat development and anisotropic HF (hydrofluoric acid) etching of the PEG substrate, followed by a metal sputtering technique. The SIW was fed by microstrip lines connected to the waveguide through tapered microstrip-to-waveguide transitions. The top metal layer, including these feedlines and transitions, was fabricated by selective metal sputtering through a silicon shadow mask, which was prefabricated by a silicon deep-reactive ion-etching (DRIE) technique. The developed PEG-based process provides a relatively simple, wafer-level manufacturing method to fabricate the SIW in a low-cost glass dielectric substrate, without the formation of individual of TGV holes, complex time-consuming TGV filling processes and repeated photolithographic steps. The fabricated SIW had a dimension of 6 × 10 × 0.42 mm3 and showed an average insertion loss of 2.53 ± 0.55 dB in the Ka-band frequency range from 26.5 GHz to 40 GHz, with a return loss better than 13.86 dB. The proposed process could be used not only for SIW-based devices, but also for various millimeter-wave applications where a glass substrate with TGV structures is required.

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Low-Loss, High-Linearity RF Interposers Enabled by Through Glass Vias

Abstract: This is the accepted version of a paper published in IEEE Microwave and Wireless Components Letters. This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination.

Cited by 25 publications

References 11 publications

Nanocrystalline diamond-glass platform for the development of three-dimensional micro- and nanodevices

Nanocrystalline diamond-glass platform for the development of three-dimensional micro- and nanodevices

RF Glass Technology Is Going Mainstream: Review and Future Applications

Fabrication of Substrate-Integrated Waveguide Using Micromachining of Photoetchable Glass Substrate for 5G Millimeter-Wave Applications

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