Low-cost DIY nano-level lithography machine! This post-95s boy is popular...
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Recently, a video of an undergraduate student making his own lithography machine went viral. Yes, you heard it right. Peng Yifeng, a student at the School of Chemical Engineering of Dalian University of Technology, successfully built a nanoscale lithography machine at home with just a blueprint , and successfully lithographyed an aperture of ~75 microns (75,000 nanometers).
This student is still an undergraduate student. The entire manufacturing process is completed on a very simple small desk. All mathematical calculations rely on a whiteboard, and all materials are piled on the table and the floor. It is simply a "model home laboratory."
It looks like this, very down-to-earth.
In the video, Peng said that the blueprint for making the lithography machine came from his classmates at Xidian University. The blueprint looks like the one below. It was with this blueprint that Peng completely replicated the entire nanoscale lithography machine.
Xiao Peng’s first reaction when he got the drawings was: Aren’t these two microscopes?
In fact, as early as May this year, Peng has released a semiconductor lithography tutorial - 1CM process tutorial . The current 75μm process was developed based on the 1cm research. Due to limited time at that time, he had only completed one layer. The truly mass-produced chips have more than one layer. Here is a simple demonstration.
In his other videos, there is preparation work, such as growing a single crystal silicon wafer , which requires covering the entire surface of the silicon wafer with an oxide layer. The photolithography mask also needs to be placed carefully, as it is very fragile and can easily break. The masked part of the NMOS board also needs to be glued.
He spent about half a year to come up with the current research results. His earliest interest came from high school. At that time, there were no videos or materials, but he just wanted to develop his own chips.
And Peng also wants to prove to everyone through the video that the environment is not important, as long as you have hands-on ability and interest!
Professional technology, ultra-low cost, challenging the limits of homemade lithography machines
Student Xiao Peng presented the entire process of making his own lithography machine in a 21-minute fast-forward video.
First, he built a micro-nano platform, with two microscopes and a laser engraving machine. The power of the engraving machine is 500 milliwatts. Because silicon wafers are reflective, goggles must be worn when engraving.
The microscope with a screen on the left was borrowed from a classmate and is mainly used to observe experimental results.
There is also a suspension coating device, which is used to coat larger equipment. A microscope is converted into a microlithography machine, and ordinary lenses are used to focus first, and then the lithography lens is used to operate after focusing.
The photolithography lens is modified with tin foil to dissipate heat and shield leaking ultraviolet rays. The connecting wire plus the LED ultraviolet lamp has a power of about 10 watts. Since ultraviolet rays can easily cause harm to the human body, it is necessary to use tin foil to cover it. The lens also needs a mask, a vernier caliper, and a yellow light to cooperate.
Photoresist is an indispensable raw material for chips. Xiao Peng spent a lot of effort and finally found a small bottle of photoresist (150 yuan). The outer bag of the photoresist is black and light-shielding, but the bug is that the bottle of photoresist is transparent, so you can't open it as soon as you get it. Once you open it casually, it will be easily exposed. It is best to open it under the background of yellow light (specific area). You also need to divide the photoresist into subpackages, about 3-4ml each time, take the glue and developer and prepare to debug it yourself.
Since the bottles of photoresist are all imported from Japan, Xiao Peng couldn't help but sigh: We still have a lot to learn and there is still a long way to go compared to the existing technology.
Why didn't we use the finished developer when preparing the developer? Xiao Peng was still a student and didn't have enough money. He used the only money he had to buy photoresist. He used distilled water from a certain company. Although it was not chain-level ultrapure water or deionized water, distilled water was fine. After repeated adjustments, the pH value of the developer was about 9.3, and about 500 ml was needed.
Then preheat the heating table to 110°C and turn on the purifier for dehumidification.
Read the photoresist instructions carefully. Before hanging the glass slide, use nitrogen to remove dust from the surface.
Then start dripping some photoresist, and then you can start the suspension coating. The details are also sufficient, and the fan speed needs to reach more than 4000 revolutions, otherwise the effect will not be achieved.
After the suspension coating is completed, place it on the preheated heating table for 90 seconds. During the process, it is best to cover it with tin foil to prevent dust and foreign matter from falling on the glass.
Next, you can set the process parameters, adjust the speed to about 2000, adjust the power to 40%, select point engraving, and select two points per mm, the dwell time is 2 milliseconds, and after all settings are completed, turn on the thermal light mode.
Then focus and start photolithography.
Then take out the developer you just prepared, but don't pour too much to prevent the concentration from being too high and leaving no space for dilution and replenishing alkali solution.
After the configuration is complete, the reflection can begin. A red substance will form on the surface of the glass, which is the redissolved photoresist.
Since it is a self-prepared developer, the positions of some parameters are not well controlled.
The location of the image is not very obvious, and only a piece of Bose development can be seen.
If you want to see the details, you can only look at it under a microscope. Some places are not well etched. In the case of the middle position, you can see that the effect is OK. The black shadow position is not processed enough and lacks some etching time.
At the highest resolution, the structure of a point is:
Based on the measurement of the pore size, it is approximately 75μm in diameter.
Netizen comments: Try the most interesting things with the most rudimentary equipment
At present, Xiao Peng's video has been played 200,000 times and has received high praise from netizens.
Some netizens advised Xiao Peng to apply for a job at Shanghai Microelectronics directly after graduation, and there were also professionals in the comment section inviting him to collaborate on research and development.
When will China be able to take off this "industrial crown"?
Photolithography technology has always been hailed as the "light of industry" and the "crown of industry."
The technologies for successfully producing semiconductor chips are mainly divided into wet cleaning, photolithography, ion implantation, dry etching, wet etching, plasma washing, heat treatment, rapid thermal annealing, annealing, thermal oxidation, chemical vapor deposition (CVD), physical vapor deposition (PVD), molecular beam epitaxy (MBE), electroplating, chemical/mechanical treatment, wafer testing and wafer polishing. Only after all these steps are successfully completed can the chips be shipped out for packaging.
It seems like there are a lot of steps, but if we look at the production process again, the second step is photolithography. That is to say, if we have not yet mastered the technical processes of 5 nanometers and 7 nanometers, the subsequent processes will basically be unable to continue .
In order to develop our own chips, countless outstanding talents are working hard day and night. It is the wish of every Chinese to localize them as soon as possible.
Just like what Xiao Peng said in his comment: He posted this step-by-step assembly instruction video of the micro-nano processing platform, challenging the limit of homemade lithography machines - 75μm process with professional technology and ultra-low cost, just to awaken more new forces to pursue and explore science and technology!
Source: Big Data Digest ID: BigDataDigest Author: Da Jieqiong The original text has been deleted
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