A Korean memory manufacturer has purchased ACM Research Shanghai’s Ultra C 12-inch, single-wafer megasonic cleaning device that uses its space-alternated phase shift (SAPS) technology. This is the company’s first order for its proprietary technology suitable for removing nanoparticles at the 45 nm production node and beyond.
The Ultra C provides higher particle removal efficiency (PRE) with less material loss and utilizes functional water having ultra-low chemical concentration without adverse chemicals. It delivers 74% PRE for removing particles between 44 and 65 nm and 96% PRE for particles at 65 nm and beyond, with material loss of below 0.2 Å/cleaning step. Thus, it offers an increase of 1.3% in production output at the 45 nm node.
ACM’s proprietary SAPS megasonic technology delivers extremely consistent megasonic power density to obtain wafer-to-wafer and within wafer non-uniformity of below 2%. Megasonic power is efficient, as the process produces cavitation or the creation of bubbles, which facilitates the removal of particles and causes them to reach the surface. It is important to control the megasonic energy’s mechanical process window in order to limit the energy to create only cavitation without damaging the patterned wafer.
Maintaining extremely consistent energy distribution throughout the wafer is highly important, as the process window for obtaining a superior PRE without producing damage is very narrow. If uniform distribution of megasonic power does not occur, the wafer will get hot spots, where megasonic power is more, thus making the bubbles to burst. ACM’s SAPS megasonic technology employs a stable cavitation bubble oscillation process, which makes the bubbles to constantly deflate and inflate without bursting.
SAPS technology offers zero-damage megasonic cleaning with extremely consistent energy distribution of 2% at 1s for superior PREs. The Founder and Chief Executive Officer of ACM Research, David Wang stated that the SAPS megasonic technology is widely acknowledged by major IC producers as a feasible tool for removing nanoparticles. The Ultra C is a better alternative to competitive cleaning technologies at the 45nm production node and above, he added. The Ultra C offers sophisticated cleaning in pre-metal, post-etch, pre-oxidation, post-implant, pre-mask and post-gate etch processes.
Source: ACM Research Inc.