ACM Research (Shanghai), Inc. has announced that it has solved the problem of patterned wafer cleaning. This is another breakthrough at ACM after it developed Space Alternating Phase Shift (SAPS) megasonic cleaning in 2011.
Compared to flat wafer cleaning, patterned wafer cleaning is much more complicated and challenging. With the decreasing line width and increasing aspect ratio, cleaning a patterned wafer without damage is much more difficult than ever. Meanwhile, as the feature size continues to shrink, the impact of fine particles (less than 30 nm) and contaminates to final device yields are much more significant.
“Finding the solution for patterned wafer cleaning has been an urgent challenge for the semiconductor equipment industry in recent years,” Dr. David Wang, President and CEO of ACM, mentioned. “When it comes to 1X nm and below manufacturing nodes, you must be capable of cleaning particle sizes smaller than tens of nm, and one cleaning step is used on average after every two non-clean processing steps in order to achieve high yield. This is where ACM’s proprietary megasonic cleaning technologies areuniquely effective.”
ACM’s newly-developed, proprietary Timely Energized Bubble Oscillation (TEBO) technology solved the problem of pattern damages caused by transit cavitation in the conventional megsonic clean process. By using TEBO, the cavitation becomes stable without bubble implosion or collapse during megasonic cleaning processing. The damage-free physical cleaning capability of TEBO with high Particle Removal Efficiency (PRE) has been demonstrated on 1X nm patterned wafers. The TEBO cleaning technology can be applied not only in FinFet manufacturing processes, but also in the high aspect ratio of DRAM and 3D NAND manufacture processes. (Aspect ratio of 30:1 or even 60:1.)