Semiconductors, microcircuits, and microchips manufacturing requires very precise condition to be maintained in the manufacturing/ processing area. Components used in assembly or processing of semiconductors are generally hygroscopic and thus are highly susceptible to high humidity conditions.
Effects of Uncontrolled Humidity
The hygroscopic components can lead to:
- Corrosion of circuits points
- Operational failure of semiconductor assembly
- Improper adhesion of photo resists
- Condensation on the microchips’ circuit surface
Ingress of corrosive gases into semiconductor assembly or manufacturing area can lead to:
- Corrosion of silver contacts by strong oxidising properties of S compounds, especially H₂S
- Corrosion of Cu/Al by SO42-
- Crystal formation by neutralisation with SO42 and NO3 with NH4+
General Recommendation
Relative Humidity in Semiconductor Assembly Manufacturing Areas should be maintained at 30% RH at 20°C (70°F). Additionally, it is important to remove any corrosive gases to protect electronic equipment and devices from the threat of abrupt failures.
Bry-Air Solution
In the assembly area, during the production of semiconductors and integrated circuits, excessive moisture adversely effects the bonding process and increases defects. Photosensitive polymer compounds called photoresists are used to mask circuit lines for etching process. Due to their hygroscopic nature, they absorb moisture resulting in the microscopic circuit lines being cut or bridged, leading to circuit failure.
Wafer Fabrication Area: During wafer manufacture the spinners spray developer on the wafer surface, causing the solvent present on the wafer to evaporate rapidly, thereby cooling the wafer surface. This results in condensation of water vapour from the air on the wafer surface. This extra water on the wafer causes characteristics of the developer to change. The resist also absorbs the moisture causing the polymer to swell. Controlling relative humidity at 30% eliminates the possibility of the cooling the wafer surface lower than the dewpoint of the air surrounding the wafer surface, thus preventing failure and spoilage.
Photo Lithography Room: Conditions in photolithography room needs to be maintained between 20% to 35% RH at about 70°F. Excessive moisture causes the silica to absorb moisture, resulting in improper adhesion of photoresist leading to stress fracture and surface defects.
Faster Vacuum Pump Down: If humidity levels are high, operation of vacuum equipment like cryopump slows down due to large load of water vapour.
Protection of EPI equipment: Water vapour or moisture condenses on chilled surfaces of epitaxial equipment corroding of components resulting in operation failure and slowdown of the process.
Bry-Air Desiccant Dehumidifiers can effectively maintain the most stringent humidity conditions required for semiconductor manufacturing areas, since they are capable of maintaining RH as low as 1% or even lower at a constant level, regardless of ambient conditions.
To avoid abrupt failures due to corrosive gases, Bry-Air Gas Phase Filtration (GPF) Systems are the ideal solution. They remove corrosive gases through the process of adsorption and chemisorption. Besides, the GPF systems neutralise odourous gases and make the environment comfortable for humans.
