Eunkee Hong

A highly manufacturable, low-thermal budget, void and seam free pre-metal-dielectric process using new SOG for beyond 60nm DRAM and other devices

New PMD (Pre-Metal Dielectric) process by employing polysilazane based inorganic SOG (spin-on-glass) is suggested for future VLSI devices. Compared with conventional SOG materials, the film made from new SOG has higher wet etch resistance, which is critical in achieving deformation-free contact profile. Additional advantages of using this new SOG process are excellent gap-fill capability upto an aspect ratio (A/R) of 20 and lower thermal budget than BPSG reflow process. Neither detrimental effect of new SOG PMD process on electrical characteristics nor device performance such as refresh characteristic, compared to HDPCVD SiO/sub 2/ was observed, indicating this is a PMD process of choice for the future devices.

Novel flowable CVD process technology for sub-20nm interlayer dielectrics

Flowable CVD (Chemical Vapor Deposition) process having merits in terms of both superior gap-fill performance of SOD (Spin-on Dielectric) and process stability of CVD was introduced for the interlayer dielectric (ILD) in sub-20nm devices based on new concept and precursor. Remote plasma during low temperature deposition and ozone treatment was adopted to stabilize the film. We also developed a novel Flowable CVD process which does not oxidize Si or electrode, resulted in removal of Si3N4 stopper layer as an oxidation or diffusion barrier. After the application of Flowable CVD to 20nm DRAM ILD, we could reduce not only loading capacitance of Bit-line by 15% but also enhance comparable productivity. Through the successful development of sub-20nm DRAM ILD Gap-fill process, Flowable CVD was successful demonstrated as a promising candidate for mass production-worthy ILD in sub-20nm next generation devices.

Robust spin-on glass gap-fill process technology for sub-30nm interlayer dielectrics

A highly robust gap-fill process technology of spin-on glass (SOG) was developed for the interlayer dielectric (ILD) in sub-30nm devices. We revealed that the filling behavior of SOG within gaps during spin-coating is mainly dependent on the capillary effect. The highly wettable surface treatment prior to SOG coating was found to enhance the gap-fill performance remarkably. This technique plays a key role in maximizing capillary effect by raising surface wettability. The filling capability was also improved by optimization of baking temperature to minimize the viscosity of SOG. It was finally found that the defects of contact bridges due to poor filling of SOG were reduced to be almost free by those unique process refinements.