Janggil Kim

Design, Fabrication, and Characterization of a Wideband 60 GHz Bandpass Filter Based on a Flexible PerMX Polymer Substrate

This paper presents a wideband 60 GHz bandpass filter fabricated on a flexible PerMX polymer substrate. A conventional parallel-coupled half-wavelength resonator filter is selected as an embedded passive device. A narrow gap of 5 μm between 750- μm-long resonators is successfully fabricated thanks to a Si support substrate. Surface modification is used to release the flexible polymer substrate from the Si substrate after the filter fabrication. A wideband filter is achieved through the optimization of the narrow gaps between the adjacent resonators. The designed filters are implemented in two different types, without a cover and with a cover. The filter without a cover shows an insertion loss of 4 dB at the center frequency of 63.5 GHz and a return loss of better than 10 dB including two CPW pads, while the filter with a cover has an insertion loss of 3.8 dB at 59 GHz and a return loss of better than 13 dB. In addition, the uncovered filter has a 3-dB bandwidth of 24% at 63.5 GHz, while the covered filter shows 28% at 59 GHz.

A novel wafer level bonding/debonding technique using an anti-adhesion layer for polymer-based zero-level packaging of RF device

This paper reports on a simple wafer scale transfer technology for polymer-based zero-level packaging. By controlling the adhesive strength of the interface between the packaging material and the carrier wafer, the ablation process of carrier wafer is substituted with the mechanical separation of it. Surface modification technique using hydrophobic SAM is selected for the formation of an anti-adhesion layer. Prefabricated BCB packaging caps on the carrier wafer is wafer-level bonded with a Si substrate and released from the carrier wafer by mechanical detachment using a razor blade. In order to confirm the validity of the technique in RF applications, the insertion loss of BCB-encapsulated CPW lines is measured from DC to 70 GHz.

BCB Cap Packaging of MEMS Switches Integrated With 100-

This paper presents benzocyclobutene (BCB) cap packaging of Microelectromechanical systems (MEMS) switches integrated with a thin monolithic microwave integrated circuit (MMIC) wafer. To prevent a possible breakage during BCB bonding process, the 100-μm-thick MMIC wafer is bonded to 680-μm-thick GaAs support before the release of MEMS switches. BCB cap packaging has been performed through BCB cap transfer technique based on antiadhesion monolayered Si carrier wafer. The thick GaAs support wafer has been separated by polymethyl methacrylate (PMMA) sacrificial etching through perforated access holes. The packaged MMIC wafer has been successfully diced using conventional dicing machine. The implemented BCB caps on the target MMIC have the height of 25 μm and the cavity of 12 μm for the housing of MEMS switches. The achieved success rate of BCB caps transfer is ~ 95%. The BCB cap packaging effect to microstrip line has been investigated through the S-parameters measurement before and after the packaging. In addition, the packaged MEMS switch shows the insertion loss of 0.7 dB, the return loss of 25 dB, and the isolation of 20 dB at 30 GHz.

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This paper presents a BCB cap packaging of MEMS switches integrated with MMIC and its electrical and mechanical effects to the packaged devices have been also investigated. To prevent a possible breakage during BCB bonding process, the 100 µm-thick MMIC wafer is bonded to 680 µm-thick GaAs support that will be finally released using PMMA sacrificial etching. The implemented BCB caps on the target MMIC have the height of 28 µm and the cavity of 13 µm for the housing of MEMS switches. The achieved success rate of BCB caps transfer is approximately 80 %. The BCB cap packaging effect to microstrip line has been investigated through the S-parameters measurement before and after the packaging. Also, the packaged MEMS switch shows the insertion loss of 0.7 dB, the return loss of 25 dB and the isolation of 18 dB at 30 GHz.

MMIC Wafer

This paper presents a new tuning mechanism for millimetre-wave BPF based on deflection of the BCB membrane of BCB packaging cap. A 3-pole parallel-coupled microstrip filter operating at 60 GHz is first implemented on 30 µm-thick BCB polymer substrate and then BCB-capped through our new anti-adhesion layer assisted wafer-level transfer technique. Gold electrodes are fabricated on top of the BCB cap for DC actuation. The implemented BCB capped BPF showed the tuning range of 1.49 GHz from 63.36 GHz to 64.85 GHz with the associated insertion losses of −9.7 dB and −9.4 dB and the return losses better than −11 dB over the tuning range.

Wafer-level BCB CAP packaging of integrated MEMS switches with MMIC

The design and fabrication of an Ultra-Wide-Band (UWB) millimeter-wave stacked-patch antenna is presented. The antenna is fabricated on silicon and takes advantage of cavity etching and BCB membranes to achieve high efficiency (>;90%), large bandwidth (30% around 57 GHz) and high gain (6-8 dBi) performances in a small area (7 mm2). The feasibility of antenna arrays is also investigated.

A Study on Millimetre-Wave Tunable Bandpass Filter Based on Polymer Cap Deflection

This paper presents a wideband 60 GHz bandpass filter fabricated on flexible 50 µm-thick PerMX polymer substrate. The implemented filter is based on conventional parallel-coupled half-wavelength resonators. Thanks to the support substrate that will be finally released, the process precision can be maintained at microfabrication level. A wideband filter has been achieved through optimization of the narrow gaps between the adjacent resonators. The implemented filter shows insertion loss of 4.2 dB at the center frequency of 63.5 GHz while its return loss is better than 14 dB including two microstrip-to-CPW transitions. In addition, 3-dB bandwidth of 19 % at the center frequency of 63.5 GHz is demonstrated.

Millimeter-wave Ultra-Wide-Band antenna array integrated on silicon with BCB membranes

This paper presents a film type PerMX polymer-based low temperature zero-level packaging technique for RF devices. PerMX polymer capping technique was developed in two different types; 1) PerMX ring and PerMX membrane, 2) SU8 ring and PerMX membrane. The height of the implemented cap was 100 µm having 50 µm thick sealing ring and 50 µm thick membrane and the implemented dimensions were 1.4×1.1 mm2, 2.1×2.1 mm2 and 5.1×5.1 mm2. Firstly, the electrical parameters of PerMX were extracted from the measured S-parameter of microstrip line. The extracted dielectric constant and loss tangent of PerMX were 2.99, 0.049 at 30 GHz respectively. Also, the effect of the PerMX package on coplanar was found to be negligible insertion loss change of the packaged transmission line while its return loss is better than 20 dB at the measured frequency range.

Wideband 60 GHz bandpass filter based on flexible PerMX polymer substrate

This paper presents the investigation of the behaviour of BCB thin-film package based on the ANSYS FEM analysis. This kind of zero-level packaging has some stress effects on a packaged device causing deformation of chip and package cap itself. BCB cap deformation and device chip deformation as a function of its residual stress are significant due to the reliablity of the packaged devices. It was found that the deformation of the two parameters worsened as BCB residual stress increases. In addition, the BCB package deformation will be presented as a function of some physical parameters of the package such as BCB sealing ring width, BCB sealing ring height and BCB membrane height.