Masayuki Furumiya

A 2.5kV isolation 35kV/us CMR 250Mbps 0.13mA/Mbps digital isolator in standard CMOS with an on-chip small transformer

An on-chip transformer-based digital isolator for intelligent power management (IPM) systems is proposed. It greatly reduces the number of chips in IPM systems by allowing integration of isolators in a CMOS chip together with MPUs or gate drivers. With a proposed pulse generation / detection scheme that enables a 5V standard CMOS transistor to utilize GHz-band signals, transformer area is reduced to 1/4∼1/8 that of conventional transformers. A test chip achieves a 2.5kV isolation voltage, a 35kV/us CMR, a 1.6mA static current and a 250Mbps data rate, all which are equal to or superior to those of photo couplers or conventional digital isolators. The high-speed low-power capability expands the application potential to include isolated serial links, medical devices, displays, sensors, etc.

On-chip vertically coiled solenoid inductors and transformers for RF SoC using 90nm CMOS interconnect technology

This paper presents very small on-chip vertically coiled solenoid inductors (V-solenoid) using 90nm CMOS multilevel interconnect technology. In addition, a variety of areas-saving (10um × 20um) transformers without any additional processing steps are demonstrated: a V-solenoid surrounded by another different inside-diameter V-solenoid (dual-tube transformer), a V-solenoid coiled around another one with same dimensions (a double-helix or DNA-like transformer), and face-to-face V-solenoids (face-to-face transformer). Radio-frequency characteristics were evaluated on the basis of 2-port S-parameter measurements. Measured self-resonance frequencies resulted in higher than 40GHz, and coupling coefficients were larger than 0.6.

Surface Control of Bottom Electrode in Ultra-Thin SiN Metal–Insulator–Metal Decoupling Capacitors for High Speed Processors

Highly reliable metal–insulator–metal (MIM) capacitor with ultra-thin SiN dielectrics is developed on the surface-controlled bottom electrode in nanometer-scales. Coverage of the TiN bottom electrode with a Ta thin layer achieves smooth surface. In addition, this electrode structure exhibits excellent etching controllability even for the MIM with the ultra-thin SiN dielectrics. The smooth surface of the Ta/TiN stacked electrode improves the dielectric characteristics such as leakage, breakdown and time-dependent dielectric breakdown (TDDB) reliability in the MIM capacitors, integrated into Cu dual-damascene interconnects (DDIs). As a result, the SiN-MIM with the Ta/TiN bottom electrode achieves high capacitance of 7 fF/µm2 as well as high reliabilities, which are 20% higher breakdown field and 6000 times longer TDDB lifetime than that without Ta-insertion. These values guarantee the high performance operation for more than 10 years under the environment at 85 °C.

Optimization of metal layers and substrate loss for the 3D solenoid structure inductors

This paper describes the optimization method on choice of the metal layers and the Si substrate structure about the 3-Dimantional(3D) vertical solenoid inductor on the CMOS process. The optimization of metal layers that constituted 3D structure inductors enable inductors, in which the two layers (Al, M6) stacked structure with area ratio of 0.3 and the three layers (Al, M6 and M5~M3) stacked structure with area ratio of 0.17, in comparison with an octagonal planer inductor. In spite of the reduction of area, the peak Q-factor on the inductor is almost equal. As for the constitution under the 3D solenoid inductors, Q-factor of inductor with PGS was lower than that of inductor without PGS, in the case of inductance <;1nH. Furthermore, the self-resonant frequency(fSR) of inductor without PGS was higher than that of inductor with PGS. As a result the inductor without PGS is available in a higher frequency domain than the inductor of PGS type.

Matching characteristics of metal resistors

This paper describes feasibility study on metal wiring resistors. Using 130nm technology node process, matching characteristics of metal wirings are discussed. It is found that precision of tungsten resistor fabricated by damascene process is as high as those of polycrystalline-silicon and polycrystalline-silicon with silicide resistors in the broad temperature. It is likely that tungsten can provide electrical, mechanical robust and highly reliable resistors.