KAIST Develops New Catalyst to Reduce Greenhouse Gases in Semiconductor Production

A new catalyst has been developed to reduce powerful greenhouse gases used in semiconductor manufacturing.

A research team led by Professor Choi Min-ki from the Korea Advanced Institute of Science and Technology (KAIST) announced on September 3 that they have created a catalyst capable of efficiently and sustainably removing the greenhouse gas carbon tetrafluoride (CF₄) emitted during semiconductor microcircuit processes, in collaboration with Samsung Electronics.

CF₄ is used in the production of semiconductor wafers, but small amounts remain after the process. It is difficult to decompose due to the strong bond between carbon and fluorine, and once released into the atmosphere, it can persist for about 50,000 years. Its impact on global warming is over 6,000 times greater than that of carbon dioxide.

CF₄ is decomposed using a catalyst that facilitates rapid and easy chemical reactions with steam at high temperatures. However, the hydrofluoric acid (HF) produced during CF₄ decomposition creates a highly corrosive environment when it interacts with moisture, causing the catalyst's fine particles to agglomerate or change structure. As a result, the performance of existing catalysts deteriorated over time.

The research team utilized the 'power of disorder.' By incorporating different types of atoms into a single structure, the arrangement becomes complex, making it less likely to agglomerate or change. The team evenly mixed several metals, including aluminum (Al), zinc (Zn), and gallium (Ga), within a single aluminate crystal structure, which remained stable even in high-temperature, humid, and fluorine-rich environments.

The new catalyst demonstrated a CF₄ decomposition rate approximately 2.3 times higher than that of existing catalysts. In experiments conducted at around 800°C for 150 hours, the CF₄ conversion rate of the existing catalyst dropped from 93% to 48%, while the new catalyst maintained a high level, decreasing from 98% to 92%. The research team stated that this technology could lead to the development of catalysts for processing various semiconductor process gases by altering the types and combinations of metals.

Professor Choi stated, "By applying the principle that disorder in nature can actually stabilize structures to catalyst design, we achieved both high CF₄ decomposition performance and long-term stability. This represents a new material design method that can be expanded to develop catalysts for processing various semiconductor process gases by changing the types and combinations of metals."