Structure and method for detecting whether narrow trench isolation grooves are etched to oxide layers based on silicon-on-insulator (SOI) silicon chip

Abstract

The invention discloses a structure and a method for detecting whether narrow trench isolation grooves are etched to oxide layers based on a silicon-on-insulator (SOI) silicon chip, and belongs to the field of micro-opto-electro-mechanical system (MOEMS) devices. The detection structure comprises a plurality of test units 2, wherein one test unit 2 is arranged in the center of the SOI silicon chip on which devices are distributed, and the other test units 2 are distributed in the circumferential direction; and each test unit 2 is divided into two test areas 4 by narrow grooves 3. The method comprises the following steps of: during etching, measuring a resistance value between the two test areas 4, and if the resistance value is more than 0, continuously etching; and if the resistance value between the two test areas 4 in each test unit 2 tends to be infinite, indicating that the trench isolation grooves on the devices are etched to the oxide layers. The structure and the method have the advantages that the inductively coupled plasma (ICP) etching condition is reflected by the change of the resistance value which is measured in real time, and the condition of severe over etching is avoided.

Description

[0001] Field: [0002] The invention belongs to the field of micro-opto-electro-mechanical (MOEMS) devices, and mainly relates to micro-electro-mechanical systems (MEMS) technology, micro-processing technology and the like. technical background: [0003] At present, in the processing technology of MEMS devices, SOI technology is one of the most widely used technologies, and many devices often require electrical isolation. To achieve this, isolation of the various parts can be achieved on the SOI wafer by means of narrow trench isolation trenches etched deep into the oxide layer. This process is used in many devices. [0004] In the paper "Two-dimensional position detection system with MEMS accelerometer for MOUSE applications" proposed by Seungbae Lee et al., for the micro accelerometer used in the mouse, if the analog and digital circuits share the same substrate, even if the substrate has a high resistance, it still cannot achieve complete detection. isolation, which would...

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Problems solved by technology

However, because the rate of ICP is not stable, the same etching rate cannot be guaranteed each time, so the repeatability of this method is not strong

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