KCTech’s supercritical fluid cleaner was being evaluated by SK Hynix for use in its DRAM production line, TheElec has learned.

SK Hynix has been procuring this equipment from Tokyo Electron, so if KCTech passes the evaluation it will become a secondary supplier, sources said.

KCTech is expected to pass the evaluation within the year, but as the use of supercritical fluid in cleaners is a sophisticated technology, it could take longer, they said.

Supercritical refers to a state where temperature and pressure are above their critical point. Fluids in supercritical states hold properties between those of liquid and gas.

This means these fluids in this state can easily dissolve unwanted residue and containment on wafers. In addition, because they have gas properties, they can go inside deep into the circuit patterns on the wafer to remove residue and containment there as well.

Supercritical fluids have been used in wafer cleaners since the production of 10-nanometer (nm) class DRAMs. Only a few fab equipment makers have commercialized the technology, such as Semes in South Korea and Tokyo Electron in Japan.

Prior to their adoption, wafers were spun around when the cleaning fluids were dried. However, this method could cause patterns to warp and patterns to mesh with nearby patterns in 10nm class chips. Supercritical fluid wafer cleaners don’t require the wafers to be spun, which helps with the yield rate of the production line.

KCTech has been collaborating on the new cleaner in secret for the past three years with SK Hynix, the sources said.

Each unit is expected to cost over 10 billion won easily, which means it was a costly investment on KCTech’s part when in came to research and development, they said.