The present invention discloses a three-axis accelerometer. The three-axis accelerometer comprises: a substrate; at least one anchor block fixedly disposed on the substrate; a first X-axis electrode, a second X-axis electrode, a first Y-axis electrode, a second Y-axis electrode, a first Z-axis electrode and a second Z-axis electrode all fixedly disposed on the substrate; a framework suspended above the substrate and comprising a first beam column, a second beam column disposed opposite to the first beam column and at least one connecting beam connecting the first beam column and the second beam column; a proof mass suspended above the substrate; and at least one elastic connection component configured to elastically connect to the at least anchor block, the connecting beam, and the proof mass. The three-axis accelerometer can realize high-precision acceleration detection on three axes with only one proof mass, and in particular, can provide a fully differential detection signal for the Z axis, thereby greatly improving detection precision.

The present invention discloses a three-axis accelerometer. The three-axis accelerometer comprises: a substrate; at least one anchor block fixedly disposed on the substrate; a first X-axis electrode, a second X-axis electrode, a first Y-axis electrode, a second Y-axis electrode, a first Z-axis electrode and a second Z-axis electrode all fixedly disposed on the substrate; a framework suspended above the substrate and comprising a first beam column, a second beam column disposed opposite to the first beam column and at least one connecting beam connecting the first beam column and the second beam column; a proof mass suspended above the substrate; and at least one elastic connection component configured to elastically connect to the at least anchor block, the connecting beam, and the proof mass. The three-axis accelerometer can realize high-precision acceleration detection on three axes with only one proof mass, and in particular, can provide a fully differential detection signal for the Z axis, thereby greatly improving detection precision.

Described herein are accelerometers, apparatus and systems incorporating accelerometers, and techniques for electrostatically adjusting a stiffness of a spring system in an accelerometer. Embodiments featuring resonant and/or quasi-static accelerometers are described. In certain embodiments, an accelerometer is a microelectromechanical systems (MEMS) device including a proof mass, an anchor, a spring attached to the proof mass, a sense electrode, and a tuning electrode. The spring and the proof mass form a spring system suspended from the anchor. The sense electrode is configured to generate a signal indicating movement of the proof mass based on application of a first signal. The tuning electrode is configured to receive an electrostatic tuning signal, the electrostatic tuning signal being separate from the first signal and providing a negative contribution to an overall stiffness of the spring system. The electrostatic tuning signal can be used to adjust the stiffness based on a measured acceleration.

Described herein are accelerometers, apparatus and systems incorporating accelerometers, and techniques for electrostatically adjusting a stiffness of a spring system in an accelerometer. Embodiments featuring resonant and/or quasi-static accelerometers are described. In certain embodiments, an accelerometer is a microelectromechanical systems (MEMS) device including a proof mass, an anchor, a spring attached to the proof mass, a sense electrode, and a tuning electrode. The spring and the proof mass form a spring system suspended from the anchor. The sense electrode is configured to generate a signal indicating movement of the proof mass based on application of a first signal. The tuning electrode is configured to receive an electrostatic tuning signal, the electrostatic tuning signal being separate from the first signal and providing a negative contribution to an overall stiffness of the spring system. The electrostatic tuning signal can be used to adjust the stiffness based on a measured acceleration.

A MEMS includes, in part, a parallel plate capacitor, a proofmass adapted to be displaced by a first distance from a rest state in response to a first voltage applied to the capacitor, and a piezoelectric material adapted to generate a second voltage in response to an external force applied to the MEMS. The second voltage causes the MEMS to transition from a standby mode to an active mode of operation. The proofmass is displaced by a second distance in response to the external force thereby causing the piezoelectric material to generate the second voltage. A spring couples the proofmass to the piezoelectric material, and a transistor turns on in response to the second voltage thereby causing the MEMS to transition to the active mode of operation. The proofmass returns to the rest state when the MEMS is in the active mode of operation.

This disclosure is related to devices, systems, and techniques for determining an acceleration. For example, an accelerometer system includes a proof mass, a pole piece connected to the proof mass, and a coil disposed around the pole piece and connected to the proof mass, where the coil is rectangular in shape. Additionally, the accelerometer system includes circuitry configured to deliver an electrical signal to the coil in order to maintain the proof mass at a null position and determine an electrical current value corresponding to the electrical signal. Additionally, the circuit is configured to identify, based on the electrical current value, an acceleration of the accelerometer system.

In a MEMS electrostatic capacitor type acceleration sensor, the manufacturing costs of MEMS elements are reduced, and at the same time, the variations of the electrical and mechanical characteristics of the MEMS elements are reduced. A detection circuit generates a voltage signal corresponding to the product of a difference between the two capacitance values of a pair of MEMS capacitors and a servo signal. A modulation circuit outputs a signal corresponding to the difference between the capacitance values using the servo signal. The control circuit outputs the servo signal on the basis of a signal corresponding to the difference between the capacitance values.

In a MEMS electrostatic capacitor type acceleration sensor, the manufacturing costs of MEMS elements are reduced, and at the same time, the variations of the electrical and mechanical characteristics of the MEMS elements are reduced. A detection circuit generates a voltage signal corresponding to the product of a difference between the two capacitance values of a pair of MEMS capacitors and a servo signal. A modulation circuit outputs a signal corresponding to the difference between the capacitance values using the servo signal. The control circuit outputs the servo signal on the basis of a signal corresponding to the difference between the capacitance values.

The disclosure describes a magnetic circuit assembly that includes a magnet assembly and an excitation ring. The magnet assembly defines a central axis and includes a pole piece and a magnet underlying the pole piece. The excitation ring includes a base and an outer ring positioned around the magnet assembly. The base includes a platform layer underlying the magnet, an upper base layer underlying the platform layer, and a lower base layer underlying the upper base layer. The outer ring overlies the upper base layer and is configured to couple to an outer radial portion of a proof mass assembly. The platform layer and lower base layer are made from high coefficient of thermal expansion (CTE) materials, while the upper base layer and outer ring are made from low CTE materials. Each relatively high CTE material has a higher CTE than each relatively low CTE material.

A method includes holding a mask using an electrostatic chuck. The mask includes a substrate having a first bump and a second bump separated from the first bump and a patterned layer. The first bump and the second bump face the electrostatic chuck. The substrate is between the patterned layer and the electrostatic chuck. The first bump and the second bump are spaced apart from the patterned layer. The first bump and the second bump are ring strips in a top view, and the first bump has a rectangular cross section and the second bump has a triangular cross section. The method further includes generating extreme ultraviolet (EUV) radiation using an EUV light source; and directing the EUV radiation toward the mask, such that the EUV radiation is reflected by the mask.