Method and device for detecting termination of etching

Abstract

Disclosed is an etching termination detection method whereby the position of termination of etching of an SOI substrate can be accurately detected irrespective of the aperture width. In a method of etching termination detection when etching an annular aperture wherein, on an SOI substrate where a silicon layer is arranged on an insulating layer, the time point at which the aforementioned insulating layer on the aforementioned silicon layer has been reached is detected, a first electrode layer is formed on the surface of an island region surrounded by the aperture formed by the aforementioned etching, an etching termination detection region is formed by forming a second electrode layer in a region outside the insulating region, the electrical resistance between the aforementioned first electrode layer and the aforementioned second electrode layer is measured, and the time point where the etching termination position has been reached is identified when a preset threshold value of the electrical resistance thereof is exceeded.

Description

technical field [0001] The present invention relates to an etching completion detection method and a device thereof when forming an annular opening reaching the insulating layer by etching the silicon layer of an SOI substrate on which a silicon layer is disposed. Background technique [0002] In a capacitive acceleration sensor in which a movable electrode and a fixed electrode are formed to detect acceleration by a change in capacitance, the movable electrode and the fixed electrode are formed on an SOI substrate. [0003] When manufacturing this capacitive acceleration sensor, a plurality of grooves are formed on the surface of the SOI substrate, for example, by resist etc. to form a pattern, and the silicon layer is dry-etched into shapes corresponding to the movable electrodes and the fixed electrodes. The etching method at this time is to calculate in advance the processing time until the insulating layer under the silicon layer is exposed, and to measure the depth usi...

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Problems solved by technology

[0004] However, if the structure of the part to be processed is miniaturized, it will be difficult to measure the depth using a laser microscope, etc., and the amount of light of a unique wavelength generated by plasma is small, so it is impossible to accurately detect the completion of etching.

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