Characterization of high-resistivity polycrystalline silicon substrates for wafer-level packaging and integration of RF passives

High-resistivity polycrystalline silicon (HRPS) wafers are explored as a novel low-cost and low-loss substrate for radio-frequency (RF) passive components in wafer-level packaging (WLP) and integrated passive networks. A record quality factor (Q=11; 1 GHz; 34 nH) and very low loss (0.65 dB/cm; 17 GHz) are demonstrated for inductors and coplanar wave guides, respectively. The waferlevel packaging solution is based on an adhesive bonding of a passive HRPS wafer to an active silicon IC wafer, where the HRPS wafer serves as a mechanical carrier and vertical spacer. This enables integration of large RF passives with a vertical spacing of >150 µm to the conductive silicon substrate containing the circuitry, while providing mechanical stability, reducing form factor and avoiding any additional RF loss. The HRPS substrates have high dielectric constant, low RF loss, high thermal conductivity, perfect thermal matching, and processing similar to the single-crystalline silicon.Philips Semiconductors and Philips Research in the context of the Philips Associate Centre at DIMES (PACD); Fundação para a Ciência e Tecnogia (FCT) (SFRH/BD/4717/2001, POCTI/ESE/38468/2001, FEDER), and the European Commission (project Blue Whale IST-2000-3006)

RF Based Remote Control for Electrical Appliances

This work presented here is to control electrical appliances through RF based remote system. From anywhere without any line of sight, RF based wireless remote control system can change the state of the electrical appliances either in off state or in on state. The controlling circuit is built around RF transmitter and RF Receiver modules which are operating at certain frequency along with a encoder and a decoder with few passive components. The four different channels at the encoder IC are used as input switches and the four channels at the decoder output are connected to the electrical devices through a relay. Here the transmission technique is amplitude shift keying (ASK) and the circuit is powered with 9 Volt. The main objective of this work is to control electrical appliances without line of sight requirement using the RF technology. It has many applications like we can control any independent electrical appliance such as T.V, room light, fan just from a remote. Operating them manually is a tedious job and become hectic sometimes. If one can control devices like fan, TV, lights and music system with a remote from a distance place just by pressing the button, life will become simpler. This will make our life more comfortable and easier

IN-SITU APPROACH FOR CHARACTERIZATION AND MODELING OF TRANSPONDER PACKAGING TECHNIQUES IN RADIO FREQUENCY INDENTIFICATION SYSTEMS

In a typical Radio Frequency Identification system, the tag-reader communication is the most important characteristic of success or failure. In this system, the tag represents the weakest link in the equation and must be selected with great care. It is also important to recognize that a passive RFID tag derives its power from the RF energy generated by the reader. In turn, it communicates to the reader by modulation of the incident RF energy to create a backscatter signal, where any power loss between the antenna and the integrated circuit chip limits the maximum distance from which the tag can be read. Because the typical assembly flow of the RFID labels requires multiple steps, different assembly methodologies are being used to lower the final cost of the RFID label. Packaged parasitic components can significantly degrade the performance of the RFID tags. Today, the most insidious problem is the loss of energy due to the mismatch between the antenna and the IC chip. The final cost and fabrication requirements for the RFID tag impose a set of criteria on the assembly of the tag, where the typical methods for extracting and characterizing parasitic components of the packaging are not feasible. This research develops the theoretical mechanism for measuring and modeling the packaging parasitic components of the passive Ultra High Frequency RFID tags. The research is based on proven antenna theory and antenna measurement methods, which in turn will provide a benchmark for the current and future assembly methods for manufacturing of the RFID labels

Substrate transfer for RF technologies

The constant pressure on performance improvement in RF processes is aimed at higher frequencies, less power consumption, and a higher integration level of high quality passives with digital active devices. Although excellent for the fabrication of active devices, it is the silicon substrate as a carrier that is blocking breakthroughs. Since all devices on a silicon wafer have a capacitive coupling to the resistive substrate, this results in a dissipation of RF energy, poor quality passives, cross-talk, and injection of thermal noise. We have developed a low-cost wafer-scale post-processing technology for transferring circuits, fabricated with standard IC processing, to an alternative substrate, e.g., glass. This technique comprises the gluing of a fully processed wafer, top down, to an alternative carrier followed by either partial or complete removal of the original silicon substrate. This effectively removes the drawbacks of silicon as a circuit carrier and enables the integration of high-quality passive components and eliminates cross-talk between circuit parts. A considerable development effort has brought this technology to a production-ready level of maturity. Batch-to-batch production equipment is now available and the technology and know-how are being licensed. In this paper, we present four examples to demonstrate the versatility of substrate transfer for RF applications

Design and modeling of a completely CMOS compatible RF varactor and a MUMPs varactor

Micro electro mechanical system (MEMS) technology has shown its bright future in many different fields, especially in space and radio frequency (RF) systems. In wireless communication systems, passive elements including tunable capacitors and inductors often need a high quality factor and high self-resonant frequency. High-quality tunable capacitors and inductors can lead to improved power or figure of merit in low noise amplifiers, low insertion loss in band-pass filters, and better phase noise and power in voltage-controlled oscillators (VCOs). By using MEMS technology, we can greatly shrink the cost and the footprint of RF circuits since all the off-chip components such as inductors and capacitors can be fabricated and integrated into a whole single chip at one time. Our research is directed by the purpose of developing more powerful RF components. The goal of this project is to build a completely on-chip IC-compatible, high-Q variable capacitor using vertical electro-thermal actuators. The variable capacitor has been accomplished through building an all-Polysilicon microstructure. The fabrication procedure is fully compatible with a standard IC integration. The research results presented at the figure1 shows an SEM of the top-view of a fabricated capacitor with a nominal capacitance value of 1900 fF

A Comparative Study Between a Micromechanical Cantilever Resonator and MEMS-based Passives for Band-pass Filtering Application

Over the past few years, significant growth has been observed in using MEMS based passive components in the RF microelectronics domain, especially in transceiver components. This is due to some excellent properties of the MEMS devices like low loss, excellent isolation etc. in the microwave frequency domain where the on-chip passives normally tend to become leakier and degrades the transceiver performance. This paper presents a comparative analysis between MEMS-resonator based and MEMS-passives based band-pass filter configurations for RF applications, along with their design, simulation, fabrication and characterization. The filters were designed to have a center frequency of 455 kHz, meant for use as the intermediate frequency (IF) filter in superheterodyne receivers. The filter structures have been fabricated in PolyMUMPs process, a three-polysilicon layer surface micromachining process.Comment: 6 pages, 15 figure

Wafer-Level Parylene Packaging With Integrated RF Electronics for Wireless Retinal Prostheses

This paper presents an embedded chip integration technology that incorporates silicon housings and flexible Parylene-based microelectromechanical systems (MEMS) devices. Accelerated-lifetime soak testing is performed in saline at elevated temperatures to study the packaging performance of Parylene C thin films. Experimental results show that the silicon chip under test is well protected by Parylene, and the lifetime of Parylenecoated metal at body temperature (37°C) is more than 60 years, indicating that Parylene C is an excellent structural and packaging material for biomedical applications. To demonstrate the proposed packaging technology, a flexible MEMS radio-frequency (RF) coil has been integrated with an RF identification (RFID) circuit die. The coil has an inductance of 16 μH with two layers of metal completely encapsulated in Parylene C, which is microfabricated using a Parylene–metal–Parylene thin-film technology. The chip is a commercially available read-only RFID chip with a typical operating frequency of 125 kHz. The functionality of the embedded chip has been tested using an RFID reader module in both air and saline, demonstrating successful power and data transmission through the MEMS coil