Wednesday, September 12, 2018

Thermal Atomic Layer Etching of copper by University of Illinois at Urbana-Champaign

Copper is a wonder metal used in moth integrated circuits but is very difficult to etch by a dry process. That is why copper is typically removed by wet chemistry or rather brutal CMP processes. So now quite fantastic news for all BEOL people who have had all kinds of problem etching copper or for those FEOL people who absolutely do not like copper - now there is a way to thermally etch copper as presented in the publication below by scientists form University of Illinois at Urbana-Champaign in the United States.

Thank you Prof. Pedersen for sharing this article on Twitter using the hashtag #ALEtch (#ALDep for ALD).

According to the abstract, the published ALE method of copper relies on:
  • a cyclic exposure to an oxidant and hexafluoroacetylacetone (Hhfac) at 275°C
  • exposure of a copper surface to molecular oxygen, O2, a weak oxidant, forms a ∼0.3 nm thick layer of Cu2O, which is removed in a subsequent step by exposure to Hhfac. 
  • the process has high selectivity and does not attack dielectrics such as SiO2 or SiNx 
  • the surface reactions are self-limiting
  • the roughness of the copper surface increases slowly over successive etch cycles 
Promising is also that rhermochemical and bulk etching data indicate that the approach should also work for other metals.

Thermal Atomic Layer Etching of Copper by Sequential Steps Involving Oxidation and Exposure to Hexafluoroacetylacetone

doi: 10.1149/2.0211809jss ECS J. Solid State Sci. Technol. 2018 volume 7, issue 9, P491-P495

Screendump from ECS Journal of Solid State Science and Technology ( 2018.12.09)


  1. As for my review of this development, I find it to be an exciting advancement that addresses the challenges associated with etching copper. The ability to etch copper using a thermal ALE method opens up new possibilities for both back-end-of-line (BEOL) and front-end-of-line (FEOL) processes. This innovation could potentially simplify manufacturing processes, improve performance, and reduce costs in the semiconductor industry. On a separate note, I would also suggest trying out Minecraft Pocket Edition Apk as a means of refreshing the mind and enhancing problem-solving abilities. Engaging in recreational activities like gaming can provide a break from technical challenges and stimulate creative thinking, which can further aid in finding innovative solutions to problems.

  2. Thank you for sharing this informative article. I am very interested in the information you have shared.

  3. Social Security Agency (SASSA) sassa status check stand as indispensable pillars in addressing a myriad of socio-economic challenges and fostering the overall well-being of vulnerable individuals and communities. These grants serve as a lifeline for millions of people across the country, offering crucial financial assistance to those who find themselves unable to adequately support themselves due to various circumstances such as unemployment, disability, or old age. By providing essential financial support, these grants not only alleviate immediate financial hardships but also contribute to the broader goal of poverty alleviation and social inclusion. They play a crucial role in ensuring that every member of society, regardless of their circumstances, has access to the resources necessary for a dignified and fulfilling life.