Method for monitoring corrosion depth of silicon in real time

Abstract

The invention discloses a method for monitoring the corrosion depth of silicon in real time, belonging to the technical field of micro-electronics mechanical system processes. The method comprises the following steps of: simultaneously corroding a silicon-corroding slice and an auxiliary silicon slice for monitoring the corrosion depth of the silicon-corroding slice under the same condition, wherein the auxiliary silicon slice comprises a corrosion groove, a corrosion surface and a monitoring surface, the corrosion groove is positioned on the surface of the auxiliary silicon slice, the corrosion surface is positioned at the bottom of the corrosion groove, the monitoring surface is positioned on the side surface of the corrosion groove, the corrosion surface and the monitoring surface have identical crystal orientations, and corrosive liquid is contained in the corrosion groove; and immersing the corrosion surface, the monitoring surface and a monitoring line formed by crossing the monitoring surface and the surface in the corrosive liquid, and then determining the corrosion depth by using the displacement of the monitoring line in a corrosion process or after the corrosion process. The method can be used for the micro-electronics mechanical system processes.

Description

technical field [0001] The invention belongs to the technical field of micro-electro-mechanical system (MEMS) processing technology, and relates to the monitoring of the anisotropic wet etching depth of silicon, in particular to a method for real-time monitoring by using a pre-patterned companion chip. Background technique [0002] As an interdisciplinary emerging advanced technology developed in the 1990s, Micro Electro Mechanical Systems (MEMS) technology has played an important role in improving people's living standards and enhancing national strength. The interdisciplinary characteristics of MEMS make it involve a wide variety of research fields and processing technologies in the development process. In recent years, with the continuous development of novelty and diversification of MEMS devices, the integration and complexity of devices have continued to increase, and the design and processing of devices are no longer limited to two-dimensional scale, but further expand...

AI Technical Summary

Problems solved by technology

However, the rate of this kind of wet etching is fast, and it is greatly affected by the concentration of local reactants and temperature, that is, the fluctuation of corrosion rate may be large, which brings difficulties to the control of corrosion depth.

[0004] Generally speaking, there are two main ways to control the etching depth: the first way is to use the characteristics of different etching rates of silicon with different doping types and doping concentrations to perform self-stop etching. This method can accurately Control the depth of corrosion accurately, but increase the complexity of the process and equipment, the change of material properties may cause incompatibility with other process steps, or introduce other unfavorable factors (such as stress); the second way is to control the reaction time In the corrosion process, it is necessary to take out the corrosion sheet several times, and use tools such as a step meter to measure the corrosion depth. When using this method, the corrosion sheet is in contact with air, and a natural oxide layer with a thickness of about 1nm will be formed. , while KOH and other anisotropic wet etchant etch silicon and silicon oxide at very different rates, this layer of uneven natural oxide layer will not only lead to deviations in corrosion uniformity, but also seriously affect the detection accuracy of corrosion rate, and Each etching depth measurement of a silicon wafer must go through multiple steps, which is very inefficient

Images