http://antonirogalski.com/wp-content/uploads/2011/12/Infrared-detectors-Status-and-trends.pdf

Infrared detectors: status and trends

An integrated circuit (IC) approach to thermal microsensors is presented. The focus is on thermal sensors with on-chip bias and signal conditioning circuits made by industrial complementary metal-oxide-semiconductor (CMOS) IC technology in combination with post-CMOS micromachining or deposition techniques. CMOS materials and physical effects pertinent to thermal sensors are summarized together with basic structures used for microheaters, thermistors, thermocouples, thermal isolation, and heat sinks. As examples of sensors using temperature measurement, we present micromachined CMOS radiation sensors and thermal converters. Examples for sensors based on thermal actuation include thermal flow and pressure sensors, as well as thermally excited microresonators for position and chemical sensing. We also address sensors for the characterization of process-dependent thermal properties of CMOS materials, such as thermal conductivity, Seebeck coefficient, and heat capacity, whose knowledge is indispensable for thermal sensor design. Last, two complete packaged microsystems-a thermoelectric air-flow sensor and a thermoelectric infrared intrusion detector-are reported as demonstrators.

Micromachined thermally based CMOS microsensors

The majority of microelectromechanical system (MEMS) devices must be combined with integrated circuits (ICs) for operation in larger electronic systems. While MEMS transducers sense or control phys ...

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Integrating MEMS and ICs

The majority of microelectromechanical system (MEMS) devices must be combined with integrated circuits (ICs) for operation in larger electronic systems. While MEMS transducers sense or control physical, optical or chemical quantities, ICs typically provide functionalities related to the signals of these transducers, such as analog-to-digital conversion, amplification, filtering and information processing as well as communication between the MEMS transducer and the outside world. Thus, the vast majority of commercial MEMS products, such as accelerometers, gyroscopes and micro-mirror arrays, are integrated and packaged together with ICs. There are a variety of possible methods of integrating and packaging MEMS and IC components, and the technology of choice strongly depends on the device, the field of application and the commercial requirements. In this review paper, traditional as well as innovative and emerging approaches to MEMS and IC integration are reviewed. These include approaches based on the hybrid integration of multiple chips (multi-chip solutions) as well as system-on-chip solutions based on wafer-level monolithic integration and heterogeneous integration techniques. These are important technological building blocks for the More-Than-Moore paradigm described in the International Technology Roadmap for Semiconductors. In this paper, the various approaches are categorized in a coherent manner, their merits are discussed, and suitable application areas and implementations are critically investigated. The implications of the different MEMS and IC integration approaches for packaging, testing and final system costs are reviewed.

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Sensing systems-on-chip (SSoCs), combining micromachined sensing structures and microelectronic building blocks on a single chip, are reviewed. While single-chip pressure and inertial sensing systems have been commercially available for more than a decade, the recent expansion of SSoC into new application areas, ranging from chemical and biochemical sensing to atomic force microscopy, demonstrates the full potential of this microsensor integration approach. Available fabrication processes for integrated sensing systems are summarized, categorizing them into pre-, intra-, and post-CMOS approaches depending on the way the micromachining module is merged with the integrated circuit (IC) technology. Examples of SSoCs are presented to highlight the different integration options, ranging from cointegration of micromachined sensors with purely analog signal chains to microsystems with cointegrated digital signal processors and digital interfaces.

Microsensor Integration Into Systems-on-Chip

This paper reports on a bulk-micromachined silicon uncooled thermal imager intended for use in automated semiconductor process control. The device has a responsivity of 15 V/W, a thermal time constant of 1 ms, and a D* of 1.6×107 cm Hz1/2/W. It is organized as a 32×32-element area array with on-chip address generation, multiplexing, and self-test circuitry. The overall chip size is 16 mm×16 mm, with a 12 mm×12 mm imaging area. Each detector consists of 32 n–p polysilicon thermocouples supported on a dielectric window and is micromachined using a novel combined front-undercut and back-etched process. An infrared camera system using the imager is also described.

A 1024-element bulk-micromachined thermopile infrared imaging array

This paper reports a bulk-micromachined silicon uncooled thermal imager intended for applications in automated process control. The device is organized as a 32x32-element area array with on-chip address generation and multiplexing. Both front-undercut and back-etched pixel structures have been explored. The pixel size in both imagers is 375pm x 375pm with a pixel area of 12" x 12" and an overall chip size of 16" x 16". The pixels consist of 32 and 36 n-p polysilicon thermocouples, respectively, and produce typical responsivities of 3 0 V N with thermal time constants of less than Smsec. Each pixel is self-testing using an embedded resistor network. The imager has an on-chip bandgap ambient temperature sensor and an optional opamp for signal amplification. The imager forms the front-end of a microprocessorcontrolled camera system that features automatic per-pixel ranging and gain control. The devices should resolve wafer temperature nonuniformities of less than 1°C in semiconductor manufacturing applications such as rapid thermal processing.

A Bulk-micromachined 1024-element Uncooled Infrared Imager

SUMMARY This paper reports a bulk-micromachined silicon uncooled thermal imager intended for applications in automated process control. The device is organized as a 32x32-element area array with on-chip address generation and multiplexing. Both front-undercut and back-etched pixel structures have been explored. The pixel size in both imagers is 375pm x 375pm with a pixel area of 12" x 12" and an overall chip size of 16" x 16". The pixels consist of 32 and 36 n-p polysilicon thermocouples, respectively, and produce typical responsivities of 30VN with thermal time constants of less than Smsec. Each pixel is self-testing using an embedded resistor network. The imager has an on-chip bandgap ambient temperature sensor and an optional opamp for signal amplification. The imager forms the front-end of a microprocessorcontrolled camera system that features automatic per-pixel ranging and gain control. The devices should resolve wafer temperature nonuniformities of less than 1°C in semiconductor manufacturing applications such as rapid thermal processing.

Andrew D. Oliver

Papers

A 1024-element bulk-micromachined thermopile infrared imaging array

A Bulk-micromachined 1024-element Uncooled Infrared Imager

A bulk-mic