US20250257465
2025-08-14
Chemistry; metallurgy
C23C16/56
A novel process is introduced for forming a vapor-deposited ZIF-8 metal organic framework (MOF) with potential applications in low-k dielectric materials. This process involves conducting a gas surface reaction between atomic layer deposited (ALD) zinc oxide (ZnO) and 2-methylimidazole. The reaction occurs at temperatures exceeding 140°C and pressures below 1000 mTorr, with a particular focus on a temperature of 160°C. The method aims to fully convert ZnO to MOF, optimizing the process to achieve desirable electrical, mechanical, and thermal properties for seamless high aspect ratio gap fill applications.
The significance of MOFs as low-k dielectrics is highlighted by their ability to reduce interconnect capacitance due to their structured material with an open fraction up to 70%. This is particularly useful in semi-damascene processing where low-k dielectrics are needed for high aspect ratio features. Previous methods for MOF thin films relied on powder synthesis, which was unsuitable for microelectronics due to scaling challenges. However, vapor-phase deposition techniques have made it feasible to incorporate MOFs into microelectronic infrastructure.
Recent studies have shown that vapor-deposited ZIF-8 MOF films can achieve k-values as low as approximately 2.2 with modest gap fill properties. The breakthrough in this patent application is the reduction in process time to just 15 minutes at a CVD temperature of 160°C. This rapid conversion process results in complete transformation of ZnO to MOF, yielding films with improved breakdown fields and thermal stability up to 450°C under vacuum conditions.
The application outlines various embodiments where vapor-deposited ZIF-8 MOFs can be used as ultra-low-k dielectrics in back-end-of-line (BEOL) interconnects. These MOFs have the potential to fill narrow trenches with sub-100 nm thickness, offering reduced interconnect capacitance while maintaining mechanical strength. By optimizing the process conditions, this technology could significantly enhance the performance and efficiency of semiconductor devices.
Several embodiments detail specific conditions for the gas surface reaction, such as temperature ranges between 140°C and 180°C and pressures up to 900 mTorr. The process can be repeated multiple times to form nanolaminate structures, further enhancing its versatility. Overall, this patent application presents a robust method for producing high-quality MOF films suitable for advanced microelectronics applications.