Sung-Ku Yeo

A 3-D X-Band T/R Module Package With an Anodized Aluminum Multilayer Substrate for Phased Array Radar Applications

This paper presents the design and development of a compact 3-D transmit/receive (T/R) module with a selectively anodized aluminum multilayer package for X-band phased array radar applications. The proposed multilayer package consists of anodized aluminum substrates and vertical interconnects with embedded vias. The proposed package platform is based on thick anodized aluminum oxide layers and active bare chips directly mounted on bulk aluminum substrates for high electrical isolation and an effective heat sink. With its combination of thin-film embedded passive components and multilayer structure, the proposed module features a compact size of 20 mm × 20 mm, with a package height of 3.7 mm. To transfer radio-frequency (RF) signals vertically, we used coaxial hermetic seal vias with characteristic 50 Ω impedances and embedded anodized aluminum vias with a solder ball attachment and flip-chip bonding. The optimized vertical interconnect structure demonstrates RF characteristics with an insertion loss of less than 1.55 dB and a return loss of less than 12.25 dB over a broad bandwidth ranging from 0.1 to 10 GHz. The fabricated X-band 3-D T/R module has a maximum transmit output power of 39.81 dBm (9.5 W), a maximum transmit gain of 41.25 dB, and a receive gain of 19.15 dB over the 9-10 GHz frequency band. The RF-signal phase amplitude control is achieved by means of a 6 bit phase shifter with an rms accuracy of more than 5° and a gain setting range of 24 dB with an rms accuracy of more than 1.5 dB. The proposed multilayer aluminum package has the advantages of reducing the module size, decreasing the cost, and managing the thermal problem for X-band high-power T/R module package applications.

Quasi-Coaxial Vertical via Transitions for 3-D Packages Using Anodized Aluminum Substrates

This letter reports on the use of quasi-coaxial vertical via transitions fabricated with a selectively anodized aluminum substrate for 3-D packages to evaluate high frequency performances. The proposed method of fabricating quasi-coaxial vertical via transitions is easier and more cost-effective than other RF MEMS processes. Vertical interconnects with embedded anodized aluminum vias are first designed and fabricated. The optimized interconnect structure demonstrated RF characteristics with an insertion loss of less than 0.75 dB and a return loss of greater than 12.4 dB over a broad bandwidth ranging from 0.1 to 10 GHz. The experimental results suggest that the developed fabrication method, which is based on the use of a selectively anodized aluminum substrate, can be used in reasonable 3-D interconnect solutions.

An oxidized porous silicon (OPS) microlens implemented on thick OPS membrane for a silicon-based optoelectronic-multichip module (OE-MCM)

Using the silicon bulk micromachining and selectively oxidized porous silicon (SOPS) technology, a silicon dioxide microlens was implemented on thick oxidized porous silicon (OPS) membrane. Because the surface of microlens was the interface of OPS-Si, the surface roughness of lens was directly affected by the anodization current density, substrate resistivity, and high-frequency percent in ethanol-contained electrolyte. In the SOPS technology, the porous silicon layer (PSL) was formed under the mask layer with its horizontal-vertical ratio of about 0.8. During the formation of lens part, Si/sub 3/N/sub 4/ mask layer was also etched with constant etch rate and the PSL formed on the masked area was used as a membrane supporter. The initial open area and the thickness of the mask layer controlled the focal length of the OPS lens and its range was from 20 to 110 /spl mu/m. By using these microlenses, a new silicon-based optoelectronic-multichip module configuration was proposed.

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.

Fabrication of the tile type transceiver module package for X-band phase array radar using selectively anodized aluminum substrate

In this paper, we proposed a tile type transceiver module package for X-band phase array radar system using a selectively anodized aluminum substrate. The proposed solution of package is based on thick anodized aluminum oxide (Al2O3) layers and bare chips mounted on aluminum for an effective heat sink. 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.

Grating metal structure with low-K benzocyclobutene and electroplated copper for high-Q spiral inductors

In this paper, we propose a grating metal structure with low-K benzocyclobutene (BCB) and electroplated copper to increase the Q-factor of a spiral inductor. The grating metal structure was fabricated using simple electroplated copper and showed a maximum quality factor (Qmax) of 4 nH in spiral inductors, which is 15% more than that in normal spiral inductors with the same metal thickness. From the proposed equivalent lumped element model, the enhancement in quality factor was found to result from the reduction in series resistance, which was caused by the increase in effective current area. This technique can be applied to increasing the Q-factor of a spiral inductor in a silicon-based radio-frequency-integrated circuit (RFIC).