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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A yaw-rate sensor having a substrate and a plurality of movable substructures that are mounted over a surface of the substrate, the movable substructures being coupled to a shared, in particular, central spring element, means being provided for exciting the movable substructures into a coupled oscillation in a plane that extends parallel to the surface of the substrate, the movable substructures having Coriolis elements, means being provided for detecting deflections of the Coriolis elements induced by a Coriolis force, a first Coriolis element being provided for detecting a yaw rate about a first axis, a second Coriolis element being provided for detecting a yaw rate about a second axis, the second axis being oriented perpendicularly to the first axis.

Yaw rate sensor

An integrated MEMS gyroscope, is provided with: at least a first driving mass driven with a first driving movement along a first axis upon biasing of an assembly of driving electrodes, the first driving movement generating at least one sensing movement, in the presence of rotations of the integrated MEMS gyroscope; and at least a second driving mass driven with a second driving movement along a second axis, transverse to the first axis, the second driving movement generating at least a respective sensing movement, in the presence of rotations of the integrated MEMS gyroscope The integrated MEMS gyroscope is moreover provided with a first elastic coupling element, which elastically couples the first driving mass and the second driving mass in such a way as to couple the first driving movement to the second driving movement with a given ratio of movement

Integrated microelectromechanical gyroscope with improved driving structure

An integrated microelectromechanical structure is provided with a driving mass, anchored to a substrate via elastic anchorage elements and designed to be actuated in a plane with a driving movement; and a first sensing mass and a second sensing mass, suspended within, and coupled to, the driving mass via respective elastic supporting elements so as to be fixed with respect thereto in said driving movement and to perform a respective detection movement in response to an angular velocity. In particular, the first and the second sensing masses are connected together via elastic coupling elements, configured to couple their modes of vibration.

Microelectromechanical gyroscope with enhanced rejection of acceleration noises

Motivated by the increasing demand of integrated inertial-sensing solutions for motion processing and dead-reckoning navigation in handheld devices and low-cost GPS navigators, this paper reports the details of a 3-axis silicon MEMS vibratory gyroscope that fulfills the pressing market requirements for low power consumption, small size and low cost. Thanks to a compact mechanical design that combines a triple tuning-fork structure within a single vibrating element, our solution achieves satisfactory performance in terms of thermal stability, cross-axis error, and acoustic noise immunity by using a small die size. Furthermore, the presence of a single primary vibration mode for the excitation of the 3 tuning-forks, together with the possibility of sensing the pickoff modes in a multiplexing fashion, allows to design a small-area, low-power ASIC.

A low-power 3-axis digital-output MEMS gyroscope with single drive and multiplexed angular rate readout

An integrated microelectromechanical structure is provided with: a die, having a substrate and a frame, defining inside it a detection region and having a first side extending along a first axis; a driving mass, anchored to the substrate, set in the detection region, and designed to be rotated in a plane with a movement of actuation about a vertical axis; and a first pair and a second pair of first sensing masses, suspended inside the driving mass via elastic supporting elements so as to be fixed with respect thereto in the movement of actuation and so as to perform a detection movement of rotation out of the plane in response to a first angular velocity; wherein the first sensing masses of the first pair and the first sensing masses of the second pair are aligned in respective directions, having non-zero inclinations of opposite sign with respect to the first axis.

Microelectromechanical gyroscope with rotary driving motion and improved electrical properties

A MEMS detection structure is provided with: a substrate having a top surface, on which a first fixed-electrode arrangement is set; a sensing mass, extending in a plane and suspended above the substrate and above the first fixed-electrode arrangement at a separation distance; and connection elastic elements that support the sensing mass so that it is free to rotate out of the plane about an axis of rotation, modifying the separation distance, as a function of a quantity to be detected along an axis orthogonal to the plane. The MEMS detection structure also includes: a coupling mass, suspended above the substrate and connected to the sensing mass via the connection elastic elements; and an anchoring arrangement, which anchors the coupling mass to the substrate with a first point of constraint, set at a distance from the axis of rotation and in a position corresponding to the first fixed-electrode arrangement.

Gabriele Cazzaniga

Papers

Integrated microelectromechanical gyroscope with improved driving structure

A low-power 3-axis digital-output MEMS gyroscope with single drive and multiplexed angular rate readout

Microelectromechanical gyroscope with enhanced rejection of acceleration noises

Microelectromechanical gyroscope with rotary driving motion and improved electrical properties

Microelectromechanical z-axis detection structure with low thermal drifts