Many semiconductor and electronics manufacturing processes and operations require closely controlled dry conditions. The presence of excessive humidity / moisture causes corrosion of 'circuit points', condensation on a microchip's circuit surface and improper adhesion of photoresists causing operational failure of the semiconductor assembly process. To provide the right working conditions in dry rooms and clean rooms, desiccant dehumidifiers are used.
Humidity Control — an important variable to:
- Prevent corrosion of 'Circuit Points'.
- Prevent condensation on microchips circuit surface.
- Protect equipment.
- Provide better adhesion of photoresists.
Thus humidity control becomes a must in the following areas:
Assembly Area
In 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 the 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 vapor 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 eliminates the possibility of cooling the wafer's surface lower than the dewpoint of the surrounding air, thus preventing failure and spoilage.
Photo Lithography Room
Conditions in a photolithography room need to be maintained. 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, is slowed down due to large load of water vapor. If the RH levels can be reduced considerably, it will result in increased batch-processing speed.
For Protection of EPI equipment
Water vapor or moisture condenses on chilled surfaces of epitaxial equipment, causing components to corrode, resulting in operation failure and slow down of the process.
Munters 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.
Next to creating optimal and dry conditions, Munters has a range of Zeol VOC Abatement products to clean exhaust air laden with Volatile Organic Compounds (VOC).