Semiconductors are integral to global connectivity, from the devices in our pockets to technological breakthroughs in sustainability across the globe. One article goes as far as claiming they ‘are what make Industry 4.0 possible’. At Flusso, we are excited by the major role flow and air velocity sensors can play in this pivotal industry, helping to stabilise semiconductor manufacturing, transfer, and maintenance.

Protecting wafers from contamination

The semiconductor manufacturing process is highly complex, requiring precise control over various environmental and process parameters to ensure the production of high-quality wafers. These wafers are thin slices of semiconductor material, such as silicon, that serve as the foundation for integrated circuits and other electronic components to be built upon.

Semiconductor wafers are extremely delicate and susceptible to contamination and physical damage. They are also often prone to oxidation when exposed to oxygen-containing environments. During manufacturing, these wafers undergo numerous processes such as photolithography, etching, doping, and chemical vapour deposition.

Each step involves using various gases and/or liquids that must be delivered at precise flow rates. Accurately measuring the flow of such matter is therefore critical, which is where flow sensors come in. Sensors help manage the environment in which the wafers are produced and transferred through measuring the gas flow that makes up almost the entirety of the wafer containers.

Semiconductor Transportation

What are FOUPs

The transfer of wafers between different stages of the manufacturing process must be conducted with precision and care. It’s paramount not only to protect the semiconductor wafers during transportation (so the products are market-viable), but to reduce the risk of handling errors and streamline the entire production line.

Semiconductor wafers are typically transported and stored in specialised plastic enclosures known as Front Opening Unified Pods — FOUPs. These specialised containers protect the wafers from contamination (such as due to outgassing), handling damage, and other environmental factors, ensuring the purity and integrity essential for high-yield semiconductor production.

As semiconductor processes advance and chip sizes decrease — such as with 5nm technology — the number of masks and processing steps increases, heightening the demand for FOUPs.

Specialised carriers: a use case concept

Controlling flow rates within the FOUPs

When wafers are within the FOUP, either on the move or awaiting the next step in the production line, even the slightest deviations in environmental quality can profoundly affect wafer stability and yield.

Nitrogen gas is commonly used to provide a stable, clean, inert atmosphere within the FOUPs. By accurately monitoring its flow, manufacturers can ensure process consistency and minimise oxygen levels, thereby protecting the integrity of the wafers.

Integrating airflow sensors within the FOUPs facilitates the implementation of advanced filtration systems such as high-efficiency particulate air (HEPA) filters or ultra-low penetration air (ULPA) filters, both of which effectively capture and remove airborne contaminants, ensuring a clean environment for semiconductor manufacturing processes.

Flusso’s flow sensors offer outstanding accuracy and repeatability; they represent a crucial addition to FOUPs by enabling the controlled environments required for semiconductor manufacturing.

Without sensors, oxygen, nitrogen and other gas levels may fluctuate uncontrollably, leading to uneven coating, adverse reactions, or deposition of impurities on the wafers, thereby compromising the manufacturing process going forward.

Alternative contamination control across the manufacturing environment

Airflow sensors also assist in managing contaminants in other ways:

• Bolstering the efficiency of HVAC and other environmental controlling technologies within manufacturing cleanrooms — by providing real-time feedback, airflow sensors enable precise control of ventilation systems, ensuring that clean air is effectively circulated throughout the cleanroom or production facility.
• Guaranteeing temperature uniformity throughout the wafer production process itself — by monitoring airflow velocity, patterns and temperature gradients across the facility, sensors will help minimise temperature variations that would otherwise impact wafer development, yield, and performance.

 

Other ways sensors can stabilise semiconductor manufacturing

Uniform processing

Semiconductor wafers must be of a uniform thickness and composition during manufacturing. An inconsistent environment — whether because of differing gases at differing rates or the impact of other contaminants — can cause variations in wafer formation, defects, and reduced yield.

Flow sensors enable real-time monitoring and adjustment of flow rates within the manufacturing environments, ensuring each wafer is processed and formed under the same conditions. This consistency is essential for producing high-performance semiconductor devices and maintaining the reliability of the end products.]

Resource optimisation

Semiconductors are pillars of modern technology and rely on a host of expensive, sometimes hazardous materials. Using these resources with utmost care is paramount, not only for yield and cost-effectiveness but also for environmental responsibility.

Flow sensors help to regulate and optimise the flow of gases (and liquids, though Flusso’s sensors don’t apply to these use cases) across the production environment. Effective resource management helps to minimise waste and reduce overall material costs, making the manufacturing process more sustainable and economically viable.

Improving overall control

The crux of it is this: Flusso’s sensors provide accurate, real-time flow data that can then facilitate the adjustment of flow parameters and other environmental conditions. Whether within the FOUP or in the broader manufacturing environment, such control helps to optimise conditions for high-yield, high-quality semiconductor wafers. Advanced flow sensors also help to detect anomalies and mitigate losses in the manufacturing process.

As with other industry applications and prospective use cases, we are enjoying working alongside partners in the semiconductor industry to refine integration and ensure our sensors directly address a range of current pain points.

Flow sensors are indispensable tools to stabilise semiconductor manufacturing, protecting delicate materials from contamination, imbalance, and damage. From smooth product transfers to uniform processing, sensors will only become more critical as already nuanced semiconductor technology continues to advance.

To learn more about the advanced capabilities of flow sensors (and how they’ll continue to evolve), feel free to get in touch with one of our experts.