Environmental performance characterization of atomic layer deposition

Abstract

Abstract-Atomic Layer Deposition (ALD) is emerging as a promising nanotechnology for manufacturing dielectrics and insulators on microelectronics devices. Its environmental performance has to be characterized at this early development stage to achieve sustainable manufacturing in the future. In this paper, we report our environmental performance characterization studies on ALD technology through material flow analysis and energy flow analysis. The assessed ALD process is for deposition of Al 2 O 3 high-k dielectric films on a 4 inch silicon wafer. The results show that only 50.4% of input Trimethyl Aluminum (TMA) material is turned into Al 2 O 3 film, while the other half is transformed into toxic emissions into the environment. Material usage efficiency of water is only 2.03% in current ALD processes. ALD is also featured with intensive energy consumption. For the studied ALD process, a total of 4.09 MJ energy is consumed for deposition of a 30 nm Al 2 O 3 film, with averaged energy consumption at 13.6 KJ per cycle.

Comparative Study of the Environmental Impact of Depositing Al2O3 by Atomic Layer Deposition and Spatial Atomic Layer Deposition

“…Inventory for Alumina Deposition Using ALD. Using the process created by Yuan et al 28 and the estimate of the ALD reactor described before, the inventory for alumina deposition using ALD was created.…”

“…The functional unit chosen for this study is the ‘deposition of a 20 nm alumina film from TMA and water on an 80 cm 2 substrate surface’. The process based on TMA and water to prepare alumina has been chosen because it is well known and widely studied in the community. − The area of 80 cm 2 corresponds to a typical 4 in. wafer.…”

Sustainable scale-up studies of Atomic Layer Deposition for microelectronics manufacturing

“…As ALD has to be operated at the vapor phase of precursor materials and requires ultra-high vacuum conditions. It has been demonstrated that the energy consumption of ALD for such process operations as heating, pumping, monitoring, controlling, etc., would contribute not only to the cost of the deposited dielectric films but also to the generation of various pollutant emissions from energy production and supply industry [14]. For the batch size production of ALD Ah03 high-k dielectric gate in semiconductor manufacturing, we have analyzed the following aspects of the ALD process to characterize its sustainability performance: ALD productivity, ALD precursor emissions, ALD process emissions, and ALD nano-wastes generations.…”

“…It has been testified that ALD operations are both material-and energy-intensive, and have a large proportion of waste/emissions generated from precursor chemical use and energy consumptions [14]. The waste and emissions could have a significant impact on the environment and public health if not fully understood and properly handled.…”

“…The environmental impact characterized for ALD Ah03 in our previous studies are also based on single wafer capacity[14][22][23]. But transferring of ALD technology from laboratory to industry scale must be carried out in a batch size production scale.…”