Semiconductor components exhibit a high sensitivity to moisture due to their intricate and delicate designs. Maintaining a dry and clean environment throughout all phases of production is essential to prevent defects and ensure optimal product quality, reliability, and performance.
Moisture can lead to oxidation and corrosion of metal layers and connections, resulting in short circuits and increased electrical resistance. It can also interfere with the lithography process, which is crucial for transferring patterns onto silicon wafers. Furthermore, moisture can undermine the integrity of packaging materials that safeguard semiconductor chips.
Desiccants play a vital role by absorbing excess moisture and maintaining dry conditions within cleanrooms and storage environments. Their effectiveness in mitigating moisture-related issues has been well established. The following sections will delve into the various types of desiccants utilized in the semiconductor industry, their specific applications, and the benefits they provide.
Common Types of Desiccants Used With Semiconductors
|
Desiccant Type |
Composition |
Applications |
Advantages |
|
Silica Gel |
Silicon dioxide |
Storage and transportation |
Non-toxic, stable, reusable after regeneration, absorbs up to 40% of its weight in moisture |
|
Molecular Sieves |
Crystalline aluminosilicates |
Lithography, etching processes |
High adsorption capacity, rapid moisture uptake, stability under extreme conditions |
|
Activated Alumina |
Porous aluminium oxide |
Air and gas drying systems |
High adsorption capacity, resistant to thermal shock, reusable after regeneration |
|
Montmorillonite Clay |
Natural clay |
Packaging and storage |
Good adsorption capacity, cost-effective |
|
Desiccant Bags |
Blend of various desiccants |
Tailored moisture control for semiconductor components |
Customisable to specific requirements, versatile in application |
Applications of Desiccants for Different Stages
Wafer Fabrication
During wafer fabrication, it is critical to maintain low humidity to ensure the accuracy of the lithography process and the integrity of chemical treatments. Desiccants, such as molecular sieves, are employed in cleanrooms to effectively control moisture levels, preventing defects that can arise from humidity fluctuations.
Packaging
In the packaging stage, semiconductor chips are enclosed in protective materials to safeguard them from physical damage and environmental factors. Desiccants like silica gel and desiccant packs are incorporated into moisture barrier bags to create a dry environment, ensuring that the chips remain free from moisture-related issues during storage and handling.
Storage and Transport
During storage and transport, semiconductor components face the risk of exposure to varying environmental conditions, which can compromise their integrity. Container desiccants are utilized in shipping containers to regulate moisture levels, providing an additional layer of protection for the components. This helps to mitigate risks associated with humidity and maintain the quality of the semiconductors throughout their supply chain journey.
