In the clean room of the semiconductor factory, operator Xiao Chen of the scanning electron microscope is observing the key line widths on the surface of the wafer. The screen suddenly showed a slight shake, and the measurement cursor began to drift - this was the low-frequency vibration brought by the ground pumping equipment transmitted to the electron microscope. No matter how he adjusted the focal length, the high magnification image that should have been sharp was still a bit off. And this deviation may mean that the critical process window for this batch of wafers has significantly narrowed, and the yield rate has plummeted accordingly.
This type of scene is not uncommon. In the environment of precision manufacturing and cutting-edge scientific research, vibration is an invisible 'equipment killer'. And to guard the process window,Vibration reduction table performanceIt has become a core issue that must be faced directly. The performance of a vibration reduction table directly determines whether the resolution of the electron microscope can be fully utilized, whether the white light interferometer can detect real sub nanometer level steps, and whether the etching accuracy of the lithography machine is stable and controllable. Unicon Technology has been deeply involved in the fields of precision measurement and laboratory environment optimization for many years. Its active vibration reduction solutions have accumulated a large number of practical cases in semiconductors, universities, and research institutes.
1、 Why traditional passive vibration damping cannot withstand 'low-frequency vibrations'
Many laboratories and factories still use air flotation springs or rubber pads for equipment vibration isolation. These schemes have a certain effect on high-frequency vibrations, but they are powerless in the low frequency range of 1Hz-200Hz. The operation of motors, the start and stop of pumps, and even the footsteps of personnel in semiconductor factories can all produce this low-frequency vibration. After passing through the air floating platform, these vibrations can still interfere with the fine scanning of the AFM probe, causing the roughness data of the profilometer to exhibit unexpected "false peaks".
Passive vibration reduction has a natural weakness - low-frequency resonance. When the input vibration frequency approaches the natural frequency of the air flotation table, it not only does not reduce the vibration, but also amplifies it. This is also why more and more high-end laboratories and production workshops are turning to active vibration reduction solutions, and the HERZ series active vibration reduction table provided by Nikon Technology is a representative product in this field.
2、 AVI-200: A "stabilizer" for desktop precision instruments
The working principle of active vibration reduction is not complicated, but to achieve true practical level vibration reduction performance, it requires a solid technical foundation. The AVI-200 series active vibration reduction table under the Unicon Technology adopts a dual-mode architecture of "active+passive": the system is equipped with a built-in piezoelectric acceleration sensor to detect incoming vibrations in real time, and the controller receives the signal and drives the piezoelectric transducer to generate a set of equal and opposite reverse compensation forces within 5-20 milliseconds, dynamically eliminating input vibrations from the source.
From the technical parameters, the active isolation range of AVI-200 is 1Hz-200Hz, the passive isolation range covers>200Hz, the vibration transmission rate above 10Hz is below -35dB, and the system noise is below 50nG/√ Hz. This means that even if there are frequent motor starts and stops around the electron microscope, the installation of AVI-200 can suppress the shaking of the equipment base to an almost negligible level.
In terms of application scenarios, the small modular design of AVI-200 is very flexible - a single module can bear 200kg, and the number of modules can be freely increased or decreased according to the size and weight of the instrument, supporting a total load of up to 400kg or more. Atomic force microscopy, white light interference profilometer, high-precision film thickness gauge, laser interferometer and other precision equipment with low to medium loads are all its "target users". By selecting the LFS low-frequency stabilizer, the active isolation lower limit of the AVI-200 can be extended to 0.5Hz, further enhancing the vibration reduction performance in the low-frequency range.
3、 AVI-400: providing a safety net for heavy-duty large equipment
When the load rises to the level of electron microscopy or lithography machine, the requirements for the performance of the vibration reduction table also upgrade accordingly. The AVI-400 series active vibration reduction table provided by Unicon Technology lowers the low-frequency isolation starting point to 0.7Hz, with a transmission rate below 0.01 (-40dB) above 10Hz and a vibration recovery time of less than 10 milliseconds.
The AVI-400 adopts a voice coil motor combined with a piezoelectric accelerometer in the driving mode, with a load capacity limit of over 800kg. Through modular expansion, it can even support large transmission electron microscopes of several tons. In the clean room of a semiconductor factory, an AVI-400 can provide active isolation for lithography machines, scanning electron microscopes, and focused ion beam equipment across the entire frequency range from 0.7Hz to 200Hz. In the materials laboratory of universities, the same AVI-400 can transform the lattice stripes of TEM atomic images from a "blurry mass" to "clearly distinguishable".
It is worth mentioning that the AVI-400 module also integrates an LCD display screen, which can monitor the vibration status in X, Y, and Z directions in real time. The vibration levels before and after installation are clearly displayed through multiple signals on the screen. This is also the most intuitive way to evaluate the performance of a vibration reduction platform - using data to verify the effect, rather than guessing based on intuition.
4、 Practical case: When a 3500 kg TEM encounters sub micron level shaking
The true test of the performance of the vibration damping table is not the numbers on the parameter table, but the performance in real scenarios. In the technical service records of Unicon Technology, there is a typical case: a 3500 kilogram FEI Titan transmission electron microscope was originally plagued by low-frequency vibration noise, and the images were not stable enough during high magnification scanning, seriously affecting the output efficiency of atomic level resolution imaging.
Faced with this ton sized behemoth, traditional air flotation vibration reduction solutions are simply powerless. The technical team of Younikon Technology ultimately adopted the modular expansion scheme of the AVI-400 series, with an isolation module placed under each of the four support legs of the electron microscope. The installation process does not even require specialized lifting equipment - simply raise the leveling feet of the electron microscope by about 5 inches to easily insert the vibration reduction module.
The effect after installation is very direct: TEM has achieved unprecedented image stability in high magnification scanning mode, completely eliminating the "image drift" phenomenon that had previously plagued operators. This case fully illustrates that the performance of advanced vibration reduction platforms is not just icing on the cake, but a key link in maintaining the process window and unleashing the full potential of the equipment.
5、 How to evaluate the suitable vibration damping table for you
When choosing a vibration reduction platform, it is recommended to conduct a comprehensive evaluation from four dimensions:
Equipment load and size: First confirm the weight and bottom space of the instrument, and then match the load-bearing capacity and modular expansion plan of different series modules.
Vibration sensitive frequency band: Analyze the main vibration source frequency of the factory or laboratory. If the operation of motors, pumps, and other equipment is concentrated in the low-frequency range (<5Hz), priority should be given to models with stronger low-frequency extension capabilities.
Response speed and recovery time: Rapid recovery capability means that even in the event of transient disturbances (such as overhead crane passing, door switches, etc.), the system can quickly restore stability without affecting continuous operation.
Installation conditions and environmental limitations: In clean room scenarios, priority should be given to selecting active vibration reduction tables that do not require air pressure, electromagnetic interference, or particle pollution risks.
About Us:
Since its establishment, Younikon Technology Co., Ltd. (Yiying Technology) has been focusing on precision thin film measurement and laboratory environment optimization. It is the general agent of Filmetrics film thickness gauge in China. We are committed to providing professional products and attentive services to safeguard your precision instruments.
