5 million USD ultra-clean laboratory for strategic technology research

Science

(Dan Tri) - During the manufacturing process of semiconductor components, even a microscopic dust particle can cause defects in the product. Therefore, every element that ensures cleanliness in this space is strictly controlled.

The clean room of the Nano and Energy Center, Faculty of Physics, University of Natural Sciences, Hanoi National University is invested with a total budget of about 5 million USD with the goal of serving research, training human resources and gradually mastering technologies related to semiconductors and microchips.

The name "clean room" comes from the requirement for almost absolute control of dust particles in the air. With microscopic semiconductor structures, even a single grain of dust can cause defects, affecting the entire component manufacturing process.

Dr. Dang Van Son, Center for Nano and Energy, Faculty of Physics, University of Natural Sciences (VNU) said: "The amount of dust in the clean room is strictly controlled by a system of machines and sensors, which are periodically inspected and maintained."

To maintain cleanliness, the air in the room is organized in a one-way flow, going from the ceiling to the floor or in a fixed direction to remove dust particles from the work area.

Before being brought into the room, air must pass through a HEPA or ULPA filtration system. In particular, HEPA filter is capable of removing at least 99.97% of dust particles from 0.3 micrometers in size, while ULPA can filter at least 99.999% of particles from 0.12 micrometers; At the same time, factors such as pressure, wall, floor and ceiling materials are also designed to limit dust intrusion and make cleaning easy.

Before entering the main area, workers must also go through the buffer room, change into specialized protective clothing and perform cleaning steps according to regulations.

After wearing specialized clothing, masks, gloves, and protective shoes properly, workers must go through the dust filter blowing chamber before entering the main space.

The main space is divided into areas with different functions, notably the white and yellow rooms.

The white room is where many equipment are arranged for thin film material fabrication, chemical processing, measurement and evaluation of materials and components characteristics such as multi-gun sputtering system, Thermal Evaporation equipment, plasma-assisted multi-chamber deep corrosion and chemical vapor thin film forming equipment (PECVD), oxidation and diffusion furnace system,...

At the Nano and Energy Center, the white room meets ISO Class 4 standards, which allows less than 10,000 dust particles of 0.1 micrometer size in one cubic meter of air.

From the layers of material formed here, the sample will continue to go through many stages before becoming a complete micro-component.

Inside the clean room there is a space with a completely different color - called the "yellow room". The entire room is covered with yellow light, light sources from outside must also be filtered to only retain the wavelength range in the yellow light region - this is a technical requirement stemming from the semiconductor device manufacturing process.

At the Nano and Energy Center, the gold room meets ISO Class 3 standards, which allows less than 1,000 dust particles of 0.1 micrometer size in one cubic meter of air.

The photolithography system is considered the central device in the entire system, responsible for shaping microscopic structures on the surface of materials to form semiconductor components.

One of the most outstanding products that the Center has successfully researched is a thermal imaging chip with the smallest size reaching 2 micrometers, equivalent to 2,000 nanometers and pixel size of 25x25 micrometers, with potential applications in many fields such as epidemiological control, smart control..., especially useful in security and defense applications, detecting the movement of objects with temperatures higher than the environment.

The gold room is also one of the areas requiring the strictest safety regulations in the clean room.

Many chemicals used in photolithography, cleaning and surface treatment processes are corrosive or toxic such as Piranha (a mixture of H2O2 with concentrated H2SO4 in a 1:3 ratio), concentrated H2SO4, HCl... Therefore, operations must be carried out inside a specialized cabinet with a toxic gas suction pipe above and a chemical discharge tank below.

Operators must also be especially careful, strictly complying with regulations on use, storage of chemicals and troubleshooting.

Unlike highly automated industrial lines, many steps in the Center's clean room are performed manually. According to Prof. Dr. Nguyen Hoang Nam, Deputy Dean of the Department of Physics, Director of the Center for Nano and Energy, this is an advantage in training.

By directly performing each step from material creation, photolithography to chemical processing, learners can clearly understand the process of making components, have skills in operating equipment, detect abnormalities and handle problems that arise during the manufacturing process.

"Students, graduate students, and graduate students can directly participate in lecturers' topics after completing training and safety control requirements. There was a time when the total number of researchers, graduate students, trainees and students participating in activities in the clean room was up to 60-70 people," Professor Nam said.

In addition to thermal imaging chips, research directions being implemented in clean rooms also include biofluidic sensor chips, memory chips that simulate brain activity and new materials for thin-film transistors... Some products have reached high levels of completion and are gradually moving towards commercialization.