Remote microwave plasma source for cleaning chemical vapor deposition chambers: Technology for reducing global warming gas emissions

Abstract

The semiconductor industry uses a large amount of perfluoro compounds (PFCs), and their impact on global warming has become a major environmental concern. In the semiconductor industry, PFC are used to periodically remove deposits from the chamber walls of chemical vapor deposition (CVD) reactors after film deposition. These chamber clean processes account for typically 50%–70% of the PFC usage in a semiconductor wafer fabrication site, the rest being mainly used for wafer-etching processes. With a conventional parallel plate radio frequency (rf) plasma reactor, the PFC gas utilization is incomplete and a large fraction of unreacted gas can be emitted in the atmosphere. This paper describes a microwave plasma source that provides as high as 99.9% utilization removal efficiency (URE) of the reactant gas (NF3) during chamber clean. This technology brings the million metric tons carbon equivalent (MMTCE) of a chamber clean to negligible levels and also enhances the chamber clean efficiency and the system throughput. Here we review the requirements for the manufacturability of a remote plasma clean process. Gaseous Fourier transform infrared and quadrupole mass spectroscopy techniques have been used to characterize the clean process, the by-products of the reaction, and the efficiency in reducing the MMTCE of CVD chamber cleans.

A Hybrid Life Cycle Inventory of Nano-Scale Semiconductor Manufacturing

“…In our inventory, we consider chamber cleaning technologies that use NF 3 remote plasma formation (plasma is formed external to the process chamber). This technology is increasingly finding adoption, because it helps reduce both GHG emissions and clean times (12). Despite this improvement, PE-CVD (a deposition process) still remains the largest contributor to GHG emissions ( Figure 4).…”

VUV photoabsorption in CF3X (X=Cl, Br, I) fluoro-alkanes

“…CF 3 I has attracted considerable interest as an alternative to environmentally unfriendly feed gases used in the plasma etching of silicon dioxide [8]. Due to the weak C-I bond it should be possible to produce high yields of CF 3 in an industrial plasma by direct electron impact dissociation of CF 3 I [9].…”

Life-Cycle Assessment of Semiconductors

“…The process change which has allowed the greatest reduction in GWP from one technology node to the next is the switch from in-situ plasma generation to remote plasma generation for etch and post-dielectric deposition chamber cleaning. (The impact of this particular technology change is not described in further detail in this thesis as it has been well-documented in previous literature [78].) …”