ACM Research Shanghai wins first order for Ultra C megasonic cleaning tool from leading Korean memory manufacturer

SHANGHAI, CHINA: ACM Research Shanghai Ltd has sold its first Ultra C 12-inch, single-wafer megasonic cleaning tool to a leading memory manufacturer based in Korea. Implementing ACM’s space alternated phase shift (SAPS) technology, the Ultra C delivers superior particle removal efficiency (PRE) with minimum material loss and uses extremely low chemical concentration functional water with no harsh chemicals. The tool will be implemented as part of the customer’s manufacturing process for its most advanced devices.

ACM’s Ultra C advanced SAPS technology shows an overwhelming improvement over alternative solutions, achieving an industry best PRE of 96 percent for particles 65 nm and above and 74 percent for particles between 44 nm and 65 nm, with material loss of less than 0.2 angstrom/cleaning step. By comparison, a competitive solution demonstrated a PRE of 84 percent for particles 65 nm and above and only 13 percent for particles between 44 nm and 65 nm in size according to customer data. With its superior PRE performance, the Ultra C offers customers a 1.3 percent increase in production yield at the 45nm node.

“This order clearly validates our cleaning technology,” said David Wang, founder and CEO of ACM Research. “Smaller device nodes have a very tight window for material loss, and the critical particle diameter is smaller, meaning that the small particles are more difficult to remove. Our SAPS megasonic technology has been proven and accepted by a leading IC manufacturer as a viable solution for removing these nano-scale particles. A clear breakthrough technology, the Ultra C is well positioned to displace current cleaning technologies at the 45 nm manufacturing node and beyond.”

The Ultra C targets advanced cleans in post-gate etch, pre-mask, post-implant, pre-oxidation, post-etch and pre-metal processes. The tool has shipped and final acceptance is expected shortly.

ACM’s proprietary space alternated phase shift (SAPS) megasonic technology enables highly uniform megasonic power density to achieve within wafer (WIW) and wafer-to-wafer (WTW) non-uniformity of less than 2 percent, compared to 10-20 percent non-uniformity offered by other single-wafer megasonic cleaning tools currently on the market.

Megasonic power is effective because the process causes cavitation (the formation of bubbles), which helps remove particles and bring them to the surface. The key is to control the mechanical process window of the megasonic energy so that there is enough energy to cause cavitation, but not so much that it causes damage to a patterned wafer.

As the process window for achieving a high PRE without causing damage is so narrow, it is critical to have excellent uniformity of energy distribution across the entire wafer. When megasonic power is not uniformly distributed, ‘hot spots’ form on the wafer where megasonic energy is higher, causing bubbles to collapse. ACM’s SAPS megasonic technology uses a stable cavitation bubble oscillation method, allowing the bubbles to continuously inflate and deflate without collapsing. SAPS technology enables damage-free megasonic cleaning with ultra-uniform energy distribution for optimal particle removal efficiencies.