Processes and Technologies for Micro and Nanoelectronics

Atomic Layer Deposition (ALD)

Fraunhofer ENAS has been researching and developing ALD processes for various applications together with the Center for Microtechnologies (ZfM) at Chemnitz University of Technology since 2006. The available processes include metallic cobalt, copper and copper-oxide films. Additionally, high-k dielectrics like aluminium oxide, hafnium oxide, and titanium oxide are available as well.

Expertise:

Materials:

  • High-k dielectrics: Al2O3, HfO2, TiO2
  • Metals: Co, Cu, (Cu2O)
  • Others on request

Equipment:

ALD system FlexAl from Oxford Instruments.
© Fraunhofer ENAS
ALD system FlexAl from Oxford Instruments.
Scia Atol200 system from scia Systems GmbH.
© Fraunhofer ENAS
Scia Atol200 system from scia Systems GmbH.
Microcluster (Roth&Rau) with two ALD-chambers and one XPS system (Prevac).
© Fraunhofer ENAS
Microcluster (Roth&Rau) with two ALD-chambers and one XPS system (Prevac).

The available tools for atomic layer deposition are, a FlexAl-chamber (Oxford Instruments), an Atol200 (scia Systems), and two chambers at the Microcluster (Roth&Rau Microsystems).

This equipment offers common standardized processes (especially at the Oxford FlexAl) with conventional bubbler evaporators for precursors revealing high vapor pressure. On the other hand, the Microcluster offers a wide flexibility for the evaluation of new precursors with its direct liquid evaporation systems. Here, precursors with a low vapor pressure can be processed, too, and further analyzed. The analysis is done using e.g. the in-vacuo XPS (x-ray photoelectron spectroscopy).

The Atol200 closes the gap between the other tools: equipped with bubblers and direct evaporation systems, ALD processes can be evaluated, developed and optimized, for a wide range of precursor systems. This is supported by integrated spectroscopic ellipsometry, and the non-contact resistance measurement chamber. All tools are designed to process 200 mm wafers. Smaller substrates can be handled and processed on request.

 

Publications and Patents

Geßner, T.; Schulz, S.E. ; Wächtler, T.; Lang, H.; Jakob, A.: Substrat mit einer Kupfer enthaltenden Beschichtung und Verfahren zu deren Herstellung mittels Atomic Layer Deposition und Verwendung des Verfahrens. DE 10 2007 058 571 B4. Chemnitz, filed 5 December 2007, and issued 16 February 2012.

Wächtler, T.; Schulz, S.E.; Gessner, T.; Mueller, S.; Tuchscherer, A.; Lang, H.: Method for the production of a substrate having a coating comprising copper and coated substrate and device prepared by this method. US 2013/0062768 A1, filed 14 September 2011, and issued 14 March 2013.

Wächtler, T.; Gessner, T.; Schulz, S.E.; Lang, H.; Jakob, A.: Substrate Having a Coating Comprising Copper and Method for the Production Thereof by Means of Atomic Layer Deposition. US 8,507,038 B2, filed 4 June 2010, and issued 13 August 2013.

Melzer, M.; Wächtler, T.; Müller, S.; Fiedler, H.; Hermann, S.; Rodriguez, R.D.; Villabona, A.: Copper Oxide Atomic Layer Deposition on Thermally Pretreated Multi-Walled Carbon Nanotubes for Interconnect Applications. Microelectronic Engineering 107 (2013) p 223–28. https://doi.org/10.1016/j.mee.2012.10.026.

Georgi, C.; Hildebrandt, A.; Wächtler, T.; Schulz, S. E.; Gessner, T.; Lang, H.: A Cobalt Layer Deposition Study: Dicobaltatetrahedranes as Convenient MOCVD Precursor Systems. Journal of Materials Chemistry C 2, 23 (2014) p 4676–82. https://doi.org/10.1039/c4tc00288a

Hu, X.; Schuster, J.; Schulz, S.E.; Gessner, T.: Simulation of ALD Chemistry of (NBu3P)2Cu(Acac) and Cu(Acac)2 Precursors on Ta(110) Surface. Microelectronic Engineering 137 (2015) p 23–31. https://doi.org/10.1016/j.mee.2015.02.017

Dhakal, D.; Khaybar A.; Lang, H.; Bruener, P.; Grehl, T.; Georgi, C.; Waechtler, T.; Ecke, R.; Schulz, S.E.; Gessner, T.: Atomic Layer Deposition of Ultrathin Cu2O and Subsequent Reduction to Cu Studied by in Situ X-Ray Photoelectron Spectroscopy. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 34, 1 (2016) p 01A111. https://doi.org/10.1116/1.4933088