As semiconductor process nodes shrink below 10nm, the definition of "clean" has fundamentally changed. Traditional HEPA and ULPA filters handle particulates effectively, but they are virtually useless against a more insidious threat: Airborne Molecular Contamination (AMC).
AMC refers to gas-phase contaminants that can condense on wafer surfaces, react with process chemicals, or corrode delicate metal features. The consequences are disastrous for fab yield rates: base contaminants cause photoresist "T-topping" in lithography, acids lead to metallic corrosion, and organics create wafer haze.
Combating this requires integrating specialized Chemical Filters directly into the ceiling Fan Filter Units (FFUs), creating mini-environments of molecular purity right above the process tools. This guide outlines how to select the right filters for specific threats.
Understanding the Target: The ABCs of AMC
To select the correct filter, you must identify the enemy. AMC is generally categorized into three primary families affecting wafer production:
Acids (MA Series): Including SOx, NOx, HCl, and HF. These cause rapid corrosion of copper interconnects and aluminum features.
Bases/Amines (MB Series): primarily Ammonia (NH3) and various amines. These are the primary culprits behind DUV photoresist T-topping defects, leading to lithography failures.
Condensable Organics/VOCs (MV Series): Volatile Organic Compounds from sealants, cleaning solvents, and off-gassing materials. These deposit on wafers, causing haze and interfering with deposition processes.
The Selection Guide: MA, MB, and MV Filters
At Deshengxin, we supply specialized chemical filters designed to target these specific spectrums. They are typically installed on the intake side of the FFU.
MA Series (Acid Removal): Utilizes treated activated carbon or ion-exchange resins specifically impregnated to neutralize acidic gases chemically. Recommended for: Etch bays, copper plating areas.
MB Series (Base/Amine Removal): Uses media treated with acidic impregnants to react rapidly with ammonia and amines. Recommended for: Lithography scanners, track/coater zones.
MV Series (VOC/Organic Removal): Features high-surface-area activated carbon with specific pore structures tuned to adsorb a wide range of organic molecules. Recommended for: General cleanroom circulation areas, deposition zones.
MAB/MAV (Combination Filters): For areas with mixed contamination profiles, multi-layered filters are available to tackle acids and bases simultaneously.
The Critical Engineering Challenge: Static Pressure
Adding a dense bed of activated carbon media (the chemical filter) on top of an existing HEPA/ULPA filter introduces a significant new problem: high resistance to airflow (static pressure drop).
A standard, off-the-shelf FFU designed only for particulate filtration will choke under this added load. The airflow velocity will drop below the required 0.45 m/s, compromising the cleanroom's integrity.
The Deshengxin Solution: High-Torque, Full-Chain Manufacturing
This pressure challenge is why Deshengxin’s "full industry chain" approach is critical for AMC control.
Unlike suppliers who assemble FFUs with generic third-party motors, we leverage over 20 years of experience to design and manufacture our own high-performance EC and AC motors in-house.
Weengineer our High-Static Pressure FFUs with specialized high-torque motors and optimized impeller geometries specifically to punch through the combined resistance of both chemical and particulate filters. This guarantees that your critical wafer production zones receive both molecularly clean air and the required airflow velocity to maintain yield.
Conclusion
Controlling AMC is no longer optional; it is a prerequisite for advanced wafer production. By selecting the correct MA, MB, or MV chemical filters and pairing them with Deshengxin’s high-torque FFUs, fabs can effectively eliminate defects like corrosion and T-topping, securing yield in the sub-nanometer era.
