Acceleration sensor and manufacturing method for the same

Abstract

The present invention easily achieves an accurate control structure for limiting displacement of a weight. An SOI substrate with a trilaminar structure including a silicon layer, a silicon oxide layer, and a silicon layer is prepared, and slits are opened by applying induced coupling plasma etching which can selectively remove only silicon from the upper side. Then, the same etching is applied from the lower side to form grooves, whereby the lower silicon layer is separated into a weight and a pedestal. Next, the structure is immersed in an etchant which can selectively remove only silicon oxide, whereby the vicinities of exposed portions of the silicon oxide layer are removed to form joint layers. A glass substrate is joined to the bottom surface of the pedestal. Piezo resistor elements are formed on the upper surface of the silicon layer to detect bending. The degree of freedom of upward displacements of the weight is accurately set based on the thickness of the joint layer.

Description

technical field [0001] The invention relates to an acceleration sensor and a manufacturing method thereof, in particular to an acceleration sensor used in mass production of small civil electronic equipment and a manufacturing method thereof. Background technique [0002] Small consumer electronic devices with built-in microprocessors, such as mobile phones, digital cameras, video games, and PDAs, are spreading rapidly. Recently, the demand for acceleration sensors built in these electronic devices or their input devices has also increased. In electronic devices with built-in acceleration sensors, accelerations such as shocks and vibrations acting on the body can be captured as digital data on a microprocessor, so it is possible to grasp the physical environment around the electronic device and perform appropriate processing. For example, in a digital camera, by detecting the acceleration acting at the moment the shutter button is pressed, it is possible to perform correctio...

AI Technical Summary

Problems solved by technology

For this reason, in order to manufacture an acceleration sensor with a control structure, an additional etching process and mechanical cutting process are required, thereby complicating the manufacturing process

In particular, in order to ensure that each batch manufactured as mass production has the same performance, it is necessary to precisely design the distance between the inertial hammer and the control structure. Among them, the technical burden is heavy, and there are also big problems from the perspective of cost reduction

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