We attempt to design and fabricate of a 4×4 Butler matrix for short-millimeter-wave frequencies by using the microfabrication process for a polytetrafluoroethylene (PTFE) substrate-integrated waveguide (SIW) by the synchrotron radiation (SR) direct etching of PTFE and the addition of a metal film by sputter deposition. First, the dimensions of the PTFE SIW using rectangular through-holes for G-band (140-220 GHz) operation are determined, and a cruciform 90 ° hybrid coupler and an intersection circuit are connected by the PTFE SIW to design the Butler matrix. Then, a trial fabrication is performed. Finally, the validity of the design result and the fabrication process is verified by measuring the radiation pattern.

The microfabrication technique based on synchrotron radiation (SR) direct etching process has recently been applied to construct PTFE microstructures. This paper proposes a PTFE substrate integrated waveguide (PTFE SIW). It is expected that the PTFE SIW contributes to the improvement of the structural strength. A rectangular through-hole is introduced taking the advantage of the SR direct etching process. First, a PTFE SIW for the Q-band is designed. Then, a cruciform 3-dB directional coupler consisting of the PTFE SIW is designed and fabricated by the SR direct etching process. The validity of the PTFE SIW coupler is confirmed by measuring the frequency characteristics of the S-parameters. The mechanical strength of the PTFE SIW and the peeling strength of its Au film are also additionally investigated.

The microfabrication technique based on SR (Synchrotron Radiation) direct etching process has recently been applied to construct PTFE microstructures. This paper attempts to fabricate an integrated PTFE-filled waveguide Butler matrix for short millimeter-wave by SR direct etching. First, a cruciform 3-dB directional coupler and an intersection circuit (0-dB coupler) are designed at 180 GHz. Then, a 4×4 Butler matrix with horn antennas is designed and fabricated. Finally, the measured radiation patterns of the Butler matrix are shown.

The metallic waveguide is one of many effective media for millimeter- and submillimeter-waves because of the advantage of its low-loss nature. This paper describes the fabrication method of PTFE-filled waveguide components with the use of the SR (synchrotron radiation) direct etching process of PTFE, sputter deposition of metal, and electroplating. PTFE is known as a difficult material to process with high precision. However, it has been reported that PTFE microstructures can be fabricated by the direct exposure to SR. First, an iris-coupled waveguide BPF with 5-stage Chebyshev response is designed and fabricated for the Q-band. It is demonstrated that the present process is applicable for the fabrication of the practical components inclusive of narrow patterns. Then, a cruciform 3 dB coupler with air-filled posts is designed and fabricated for the Q-band. Directivity and matched state of the coupler can be realized by “holes” in the dielectric material. The measurement results are also shown.

An ultra-deep polymer cavity structure exposed using deep X-ray lithography is used as a template for metal electroforming to produce a 24-GHz cavity resonator. The metal cavity is 1.8 mm deep and has impressive structure, including extremely vertical and smooth sidewalls, resulting in low conductor loss. The measured resonator has an unloaded quality factor of above 1800 at a resonant frequency of 23.89 GHz.

A 0.25-µm BiCMOS technology has been developed using three sophisticated technologies; the HSST/BiCMOS device, synchrotron orbital radiation (SOR) X-ray lithography, and an advanced two-level metallization. The HSST/BiCMOS provides a 25.4-ps double-poly bipolar device using High-performance Super Self-Aligned Process Technology (HSST), and a 42 ps/2 V CMOS inverter. SOR lithography allows a 0.18 µm gate and 0.2 µm via-hole patternings by using single-level resists. The metallization process features a new planarization technique of the 0.3-µm first wire, and a selective CVD aluminum plug for a 0.25 µm via-hole with contact resistance lower than 1Ω. These 0.25-µm technologies are used to successfully fabricate a 4 KG 0.25 µm CMOS gate-array LSI on a BiCMOS test chip of 12 mm square, which operates at 58 ps/G at 2 V. This result demonstrates that SOR lithography will pave the way for the fabrication of sub-0.25-µm BiCMOS ULSIs.

The minimum transferable linewidth by X-ray is derived using waveguide analysis. The minimum width is determined by the refractive index of the absorber and does not depend on the X-ray wavelength. Therefore there is an optimum mask aperture size which provides the minimum linewidth. By using Au as the absorber, 8 nm linewidth is attainable.