Membrane stress testing structure and method as well as manufacturing method

Abstract

The invention discloses membrane stress testing structure and method as well as a manufacturing method. The membrane stress testing structure is configured on the surface of a substrate of a micro electro mechanical system and comprises a first fixed base, a second fixed base, a cantilever beam and a main scale, wherein the first fixed base and the second fixed base are both configured on the substrate and consist of a sacrifice layer formed on the substrate and a thin film to be tested, which is formed on the sacrifice layer; the cantilever beam is in a suspended structure formed by the thin film to be tested and comprises a test beam, a slope beam and an indication beam, wherein one end of the indication beam is in a comb structure and forms a vernier; and the main scale consists of the sacrifice layer formed on the substrate and the thin film to be tested, which is formed on the sacrifice layer, and the main scale is in a comb structure configured on the substrate and used for reading the displacement of the indication beam by matching with the vernier. The membrane stress testing structure and method as well as the manufacturing method can accurately measure the membrane stress without using the Poisson ratio of materials to be tested and can also accurately measure the local region stress.

Description

technical field [0001] The invention relates to a micro-electromechanical system (MEMS) testing technology, in particular to a film stress testing structure, testing method and manufacturing method. Background technique [0002] The existing micro-electromechanical system (MEMS) is similar to the integrated circuit (IC). It also prepares a certain circuit or structure on a single crystal silicon wafer through thin film deposition, diffusion, photolithography, etching, hollowing out and other processes. Certain effects of mechanics achieve the purpose of sensing a certain signal or executing it. [0003] However, there are also differences between MEMS and traditional integrated circuits. This difference is mainly reflected in the standardization of its preparation process. The materials and processes used in integrated circuits have reached a high degree of standardization in the industry, while micro-electro-mechanical systems cannot be standardized in a short period of ti...

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Problems solved by technology

[0010] However, many of the materials used in MEMS are non-standard materials, and their Poisson's ratio is often unknown or incompletely determined, and will not be integrated in the software of the stress tester.

Even though the strain gauge can still measure the radius of curvature of the film optically, it cannot calculate the stress of the film using the Stoney formula

[0011] This method has another disadvantage: the measured stress is for the film on the entire wafer and cannot reflect the stress characteristics of a local area

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