Effect of Surfactant in Gas Dissolved Cleaning Solutions on Acoustic Bubble Dynamics

Megasonic cleaning is one of the promising technologies to remove the particles during semiconductor processing. Acoustic bubble cavitation plays a key role in removing the particles. In this work, the effect of an anionic surfactant sodium dodecyl sulfate (SDS) on a bubble in the presence of hydrogen dissolved DIW water was studied. The bubble dynamics were observed using a high-speed camera. It was found that with the increase of surfactant the bubble characteristics were changed very significantly. Several parameters affecting the bubble dynamics were investigated.

Interaction between Free-Surface Oscillation and Bubble Translation in a Megasonic Cleaning Bath

Visualization experiments were performed to study the relation between free-surface motion and bubble translation in a 1-MHz ultrasonic cleaning bath. From the visualization with a video camera, the characteristic frequencies of the free-surface oscillation (under the acoustic radiation force) and the translational velocity of cavitation bubbles (trapped via the primary Bjerknes force) were extracted, showing that there is a strong correlation between the free-surface oscillation and bubble translation. From the context of megasonic cleaning, such free-surface oscillation is expected to contribute to uniform cleaning performance with cavitation bubbles.

Scalable Particle Removal for sub-5 nm Nodes

Wet cleaning has become challenging as the feature size of semiconductor devices decreased to sub-5 nm nodes. One of the key challenges is removing various types and sizes of particles and contamination from complex and fragile 3D structures without pattern damage and film loss. Conventional physical cleaning methods, such as dual-fluid spray or megasonic cleaning, are being used for the particle removal process. However, in advanced device nodes, these methods induce pattern damage and film loss. In this paper, we describe a novel particle removal technology called Nanolift which uses a polymer film consisting of two organic resins with different functions and achieved high particle removal efficiency on various types and sizes of particles with no pattern damage and minimum film loss.