Damage-Free Design of a Megasonic Waveguide for Single-Wafer Processing

Abstract

Megasonic cleaning process as a wet cleaning process is routinely used in the semiconductor industry for the removal of contaminant particles from wafer surfaces. The wafer surfaces can be cleaned effectively by choosing the proper chemicals, acoustic pressure, and the frequency of acoustic field. In the present study, we propose the design improvement of a megasonic waveguide to minimize wafer damage from the bubble cavitation. The conventional direct-type waveguide is compared with the newly designed and developed indirect-type waveguide in terms of its performance in minimizing the damage of wafers having 70 nm poly-Si patterns.

Lattice Boltzmann Simulation of Cavitation and Particle Behavior Induced by Sonication Transducer

“…Higher power and frequency, however, may not give optimistic result based on result of ref. [2] which implies optimum frequency is exist for particle removal efficiency of megasonic cleaning process.…”

“…Also, resultant effect of varying transducer power and frequency on pattern damage and particle removal efficiency (PRE) is reported elsewhere [2]. For the removal of nanoparticles, however, its mechanism is not revealed clear yet.…”

“…It is reported that the cleaning of submicron particles by megasonic process is dominated by fluid pressure gradient and gas-liquid interface which are induced by oscillating motion of bubble [1]. Also, resultant effect of varying transducer power and frequency on pattern damage and particle removal efficiency (PRE) is reported elsewhere [2]. For the removal of nanoparticles, however, its mechanism is not revealed clear yet.…”

Optimization of CO2 Gas Cluster Generation for Cleaning Application

“…Generally, surface contaminants have been removed from substrate surfaces by wet cleaning processes. Although wet cleaning processes efficiently remove contaminants, they have several undesirable effects (1). So, dry damage-free cleaning processes have been investigated extensively, and of these processes, cryogenic aerosol cleaning, has been used successfully to remove contaminant particles from the surface of semiconductor wafers (2).…”

Dependency of the Underlying Surface Condition on Dielectric Film Removal at Wafer Edge

“…6 Until recently, many semiconductor companies had been using batch cleaning systems [7][8][9][10] that are used for a wet process. However, the adoption of a single wafer spin tool 6,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] has become mainstream for the cleaning process on the back side, frontside, and wafer edge etching because the process control and flexibility are considered to be superior to that of batch systems. 6,11,12 For edge etching using a single wafer spin tool, chemical liquids are supplied toward the edge of the front of the wafer from the wafer back side by diffraction.…”