Stress test structure based on electrostatic force driving and test method

Abstract

The invention relates to a collision stress test structure based on electrostatic force driving. The structure comprises a substrate, an oxide layer, an anchor area, a bulge structure, a stop structure, a spring structure, a cantilever beam, a mass block and an electrode. An oxidation layer is arranged on the substrate, an anchor area is arranged on the oxidation layer, the protruding structure is fixed above the substrate through the position of the anchor area, the mass block is connected with the anchor area through a spring structure and can move along the symmetric center line, the stop structure is connected with the mass block, and a plurality of cantilever beams are arranged on the two sides of the mass block and form a group of comb tooth structures with the cantilever beams on the anchor area. When voltage is applied, the electrostatic force effect enables the mass block to move downwards, when the mass block moves to a preset position, the voltage is cut off, and the spring structure elastically rebounds to rise and strikes the protruding structure. Due to the fact that the distance between the comb teeth is larger than the distance between the movable structure and the bottom anchor area blocking structure, the mass block can fully obtain the motion space, and therefore controllable collision force is applied to the protruding structures during springback collision. The test structure can be used for accurately testing the impact resistance of areas such as cantilever beams, microbridges or films in the field of micro-nano processing.

Description

Technical Field

[0001] The present invention relates to the field of MEMS (micro-mechanical electronic systems) testing technology, and in particular to a microstructure stress testing structure based on electrostatic drive, which is particularly suitable for measuring the dynamic stress bearing capacity of local weak areas in micro-nano structures. Background Art

[0002] With the widespread application of MEMS devices in inertial sensing, biosensing, optoelectronic systems, and other fields, the mechanical reliability of device structures has become a key factor limiting their performance and lifespan. Especially at the micro- and nanoscale, structures contain numerous localized stress concentration areas, such as sharp corners, thin films, and connecting bridges. These areas are often the initial points of device failure. Therefore, accurate and reliable stress testing of these areas has become a crucial step in device development and reliability assessment.

[0003] In existing technologies, static mechanical testing of microstructures is often performed using methods such as nanoindentation, atomic force microscopy (AFM) loading, and piezoelectric loading platforms. However, these testing methods have the following limitations:

[0004] 1. Limited loading methods: Traditional methods are mostly static loading or quasi-static pressing, which makes it difficult to simulate structural responses under high-speed or sudden impact conditions;

[0005] 2. The loading area is not concentrated: Due to the probe size or control accuracy issues, it is difficult to achieve precise loading of micron-level sharp corners and small areas;

[0006] 3. Low device integration: Some test devices are difficult to be compatible with the MEMS processing flow, the test process is complicated, and they are not suitable for batch testing.

[0007] To address these issues, electrostatic actuation, a low-power, high-precision, and easily integrated microstructure actuation method, is widely used in MEMS actuators and sensors. This invention, based on this principle, achieves rapid displacement and rebound impact of the structure by controlling the voltage application and release process, thereby completing stress loading testing of the target microstructure area. Summary of the Invention

[0008] Purpose of the invention: The purpose of the present invention is to overcome the problems existing in existing microstructure stress testing means, such as single testing method, weak impact simulation capability, and insufficient testing accuracy of local areas, and to provide a microstructure stress testing structure based on electrostatic drive. The structure can achieve rapid acceleration and rebound of the movable structure through voltage control, thereby performing a directional impact on the set target area on its rebound path, thereby realizing the stress bearing capacity test of the local area of the microstructure under dynamic load.

[0009] Technical solution: In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is:

[0010] The present invention discloses an electrostatically driven impact stress test structure designed to test the maximum stress that a specific structural area can withstand. The structure includes a substrate, an oxide layer, an anchor region, a protrusion structure, a stop structure, a spring structure, a cantilever beam, a mass, and electrodes. The substrate is provided with an oxide layer, and the oxide layer is provided with an anchor region. The protrusion structure is fixed above the substrate by the anchor region. The mass is connected to the anchor region by a spring structure and is located in the middle of the structure, movable along a symmetrical midline. The stop structure is connected to the mass. Multiple cantilever beams are provided on both sides of the mass, forming a comb structure with the cantilever beams on the anchor region. When voltage is applied, the electrostatic force causes the mass to move downward. When the mass moves to a preset position, the voltage is disconnected, causing the spring structure to elastically rebound and rise, impacting the protrusion structure. Because the comb teeth spacing is much larger than the distance between the movable structure and the bottom anchor region blocking structure, the mass has ample space for movement, thereby applying a controllable impact force to the protrusion structure during rebound impact. This test structure can be used in the field of micro-nano processing to accurately test the impact resistance of areas such as cantilever beams, microbridges, or thin films.

[0011] Beneficial effects: The present invention realizes dynamic stress loading in local areas of microstructures through electrostatic drive, which can effectively simulate the collision stress conditions of micro-nano devices when subjected to instantaneous impact or vibration in actual work. Compared with existing nanoindentation or quasi-static loading methods, this structure can achieve precise adjustment of impact energy by controlling the size and mass of the mass block, the voltage and the loading time. It is suitable for testing microstructure areas of different shapes and materials. The structure can be tested repeatedly, and can achieve precise repeated collisions and thus realize the detection of collision fatigue. The device has a compact structure and is easy to integrate into the MEMS process flow. It has high repeatability and high-precision testing capabilities, and can be combined with optical, capacitance or strain detection methods for multi-dimensional analysis. It has high testing efficiency and a wide range of applications, and has good promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the present invention;

[0013] Figure 2 This is a schematic diagram of the split structure of the present invention;

[0014] Figure 3 It is a side view of the present invention. DETAILED DESCRIPTION

[0015] In order to deepen the knowledge and understanding of the present invention, the present invention is further described below with reference to the accompanying drawings.

[0016] Example: Figure 1-Figure 3 As shown, a collision stress test structure driven by electrostatic force is shown. The test structure includes a substrate 1, an oxide layer 2, an anchor area 3, a protruding structure 4, a stop structure 5, a spring structure 6, a cantilever beam 7, a mass block 8, an electrode A9, an electrode B10 and an electrode C11. The substrate 1 is provided with an oxide layer 2, and the oxide layer 2 is provided with an anchor area 3. The protruding structure 4 is fixed above the substrate 1 through the anchor area 3. The mass block 8 is connected to the anchor area 3 through the spring structure 6, is located in the middle of the structure, and can move along the symmetrical midline. The stop structure 5 is connected to the mass block 8. A plurality of cantilever beams 7 are provided on both sides of the mass block 8, forming a group of comb tooth structures with the cantilever beams 7 on the anchor area 3. A limiting structure anchor area 3 is provided at the bottom of the mass block 8 for limiting its maximum downward position. Electrode A9, electrode B10 and electrode C11 are all provided on the anchor area 3.

[0017] Example 2: See Figure 1-Figure 3 , a test method based on electrostatic force driven collision stress test structure, the specific steps are as follows:

[0018] Step 1: Fix the completed test device on the test platform and use probes or leads to correctly connect electrodes A, B and C.

[0019] Step 2: Apply a control voltage between electrode A and electrode B to make the mass 8 move downward in the vertical direction under the action of electrostatic force. At the same time, monitor the resistance change between electrode A and electrode C.

[0020] Step 3: When the resistance between electrode A and electrode C changes, the applied voltage is quickly disconnected, and the elastic restoring force of the spring structure 6 is used to make the mass block 8 rebound upward quickly, and the top stop structure 5 hits the protruding structure 4.

[0021] Step 4: Observe the fatigue condition of the protruding structure 4. The voltage or loading times can be adjusted as needed, and multiple impact tests can be performed on the same structure to evaluate its fatigue characteristics or critical failure strength.

[0022] It should be noted that the above embodiments are not intended to limit the scope of protection of the present invention, and equivalent changes or substitutions made on the basis of the above technical solutions fall within the scope of protection of the claims of the present invention.

Claims

1. A collision stress test structure based on electrostatic force driving, characterized by: The test structure comprises a substrate (1), an oxide layer (2), an anchoring area (3), a protruding structure (4), a stopper structure (5), a spring structure (6), a cantilever beam (7), a mass block (8), an electrode A (9), an electrode B (10), and an electrode C (11). The substrate (1) is provided with an oxide layer (2), the oxide layer (2) is provided with an anchoring area (3), the protruding structure (4) is fixed above the substrate (1) via the anchoring area (3), the mass block (8) is connected to the anchoring area (3) via the spring structure (6), a plurality of cantilever beams (7) are provided on both sides of the mass block (8), and a group of comb teeth structures are formed with the cantilever beams (7) on the anchoring area (3), a limiting structure anchoring area (3) is provided at the bottom of the mass block (8) for limiting its maximum downward displacement position, and the electrode A (9), the electrode B (10), and the electrode C (11) are all provided on the anchoring area (3).

2. The electrostatic force driven impact stress testing structure according to claim 1, characterized in that: The mass block (8) achieves rapid rebound after power failure through the spring structure (6).

3. The electrostatic force driven impact stress testing structure according to claim 1, characterized in that: The mass block (8) is located in the middle of the test structure and can move along the symmetrical center line. The stop structure (5) is connected to the mass block (8).

4. The electrostatic force driven impact stress testing structure according to claim 1, characterized in that: The anchor area (3) is located at the bottom of the test structure and is used to protect the device structure and ensure that the displacement amplitude is consistent.

5. The electrostatic force driven impact stress testing structure according to claim 1, characterized in that: The shape of the protruding structure (4) is adjusted according to requirements.

6. A test method based on an electrostatic force driven impact stress test structure, characterized in that: Using the test structure according to any one of claims 1 to 5, the method is as follows: Step 1: Fix the completed test device on the test platform and use probes or leads to correctly connect electrode A (9), electrode B (10) and electrode C (11). Step 2: Apply a control voltage between electrode A (9) and electrode B (10) to make the mass (8) move downward in the vertical direction under the action of electrostatic force, and monitor the resistance change between electrode A (9) and electrode C (11) at the same time. Step 3: When the resistance between electrode A (9) and electrode C (11) changes, the applied voltage is quickly disconnected, and the elastic restoring force of the spring structure (6) is used to make the mass block (8) rebound upward quickly, and the top stop structure (5) hits the protruding structure (4). Step 4: Observe the fatigue condition of the protruding structure (4). According to the requirements, the voltage or the number of loading times can be adjusted. Multiple impact tests can be performed on the same structure to evaluate its fatigue characteristics or critical failure strength.

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