Silicon wafers are fundamental components in the semiconductor industry, serving as the substrate for most electronic devices. Ensuring their cleanliness is crucial for the performance and reliability of these devices. This blog post explores the importance of silicon wafer cleanliness and how contact angle measurements can be used to evaluate it.
Silicon wafers undergo several processing steps, including ingot growth, slicing, cleaning, and polishing. Among these, the cleaning and purification processes are critical to ensuring the wafers are suitable for use in semiconductor applications. Contaminants on the wafer surface can lead to defects in electronic circuits, affecting device performance and yield.
The cleaning process typically involves removing organic, inorganic, and metallic contaminants. Techniques such as RCA cleaning, which uses a mixture of chemicals, are commonly employed to achieve ultraclean surfaces. These methods are continually evolving to meet the increasing demands for cleaner surfaces in advanced semiconductor manufacturing.
Contact angle measurements provide a quantitative method for assessing the cleanliness of silicon wafers.
This technique involves measuring the angle formed by a liquid droplet on the wafer surface. The contact angle indicates the wettability of the surface, which is influenced by its cleanliness. Example of water contact drop on dirty (upper image) and cleaned (lower image) glass slide can be seen here.
One advantage of contact angle measurement is that it is non-destructive, allowing for the continuation of the processing after the measurement is done. Contact angle also provides a quantitative measure of surface cleanliness, which is crucial for quality control in semiconductor manufacturing. In addition, contact angle measurements can be performed quickly, facilitating rapid assessment of wafer cleanliness during production.
The cleanliness of silicon wafers is a critical factor in the semiconductor industry, directly impacting device performance and reliability. Contact angle measurements offer a reliable and efficient method for evaluating surface cleanliness, ensuring that wafers meet the stringent requirements of modern electronic applications. As technology advances, maintaining ultraclean wafer surfaces will remain a priority, and techniques like contact angle measurement will continue to play a vital role in achieving this goal.
Susanna is an Application Scientist at Biolin Scientific. In her PhD thesis, she developed fabrication methods for a new type of inorganic-organic polymers. Microfabricated polymer chips were utilized as tool for biomolecule separation in analytical chemistry.
