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Thin films of copper oxide and copper grown by atomic layer deposition for applications in metallization systems of microelectronic devices

Abstract

Copper-based multi-level metallization systems in today's ultralarge-scale integrated electronic circuits require the fabrication of diffusion barriers and conductive seed layers for the electrochemical metal deposition. Such films of only several nanometers in thickness have to be deposited void-free and conformal in patterned dielectrics. The envisaged further reduction of the geometric dimensions of the interconnect system calls for coating techniques that circumvent the drawbacks of the well-established physical vapor deposition. The atomic layer deposition method (ALD) allows depositing films on the nanometer scale conformally both on three-dimensional objects as well as on large-area substrates. The present work therefore is concerned with the development of an ALD process to grow copper oxide films based on the metal-organic precursor bis(trin- butylphosphane)copper(I)acetylacetonate [({sup n}Bu{sub 3}P){sub 2}Cu(acac)]. This liquid, non-fluorinated {beta}-diketonate is brought to react with a mixture of water vapor and oxygen at temperatures from 100 to 160 C. Typical ALD-like growth behavior arises between 100 and 130 C, depending on the respective substrate used. On tantalum nitride and silicon dioxide substrates, smooth films and selfsaturating film growth, typical for ALD, are obtained. On ruthenium substrates, positive deposition results are obtained as well. However, a considerable intermixing of the ALD copper oxide with the  More>>
Publication Date:
May 25, 2010
Product Type:
Thesis/Dissertation
Report Number:
ETDE-DE-2319
Resource Relation:
Other Information: TH: Diss. (Dr.-Ing.)
Subject:
36 MATERIALS SCIENCE; CARBOXYLIC ACID SALTS; COPPER; COPPER OXIDES; DECOMPOSITION; ELECTRON SPECTRA; ELECTROPLATING; ENERGY LOSSES; ENERGY SPECTRA; FORMIC ACID; LAYERS; MIXING; REDUCTION; ROUGHNESS; RUTHENIUM; SCANNING ELECTRON MICROSCOPY; SILICON OXIDES; SUBSTRATES; TANTALUM NITRIDES; TEMPERATURE RANGE 0273-0400 K; TEMPERATURE RANGE 0400-1000 K; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY
OSTI ID:
21350290
Research Organizations:
Technische Univ. Chemnitz (Germany). Fakultaet fuer Elektronik und Informationstechnik
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
TRN: DE10GC656
Availability:
Commercial reproduction prohibited; OSTI as DE21350290
Submitting Site:
DE
Size:
245 pages
Announcement Date:
Dec 01, 2010

Citation Formats

Waechtler, Thomas. Thin films of copper oxide and copper grown by atomic layer deposition for applications in metallization systems of microelectronic devices. Germany: N. p., 2010. Web.
Waechtler, Thomas. Thin films of copper oxide and copper grown by atomic layer deposition for applications in metallization systems of microelectronic devices. Germany.
Waechtler, Thomas. 2010. "Thin films of copper oxide and copper grown by atomic layer deposition for applications in metallization systems of microelectronic devices." Germany.
@misc{etde_21350290,
title = {Thin films of copper oxide and copper grown by atomic layer deposition for applications in metallization systems of microelectronic devices}
author = {Waechtler, Thomas}
abstractNote = {Copper-based multi-level metallization systems in today's ultralarge-scale integrated electronic circuits require the fabrication of diffusion barriers and conductive seed layers for the electrochemical metal deposition. Such films of only several nanometers in thickness have to be deposited void-free and conformal in patterned dielectrics. The envisaged further reduction of the geometric dimensions of the interconnect system calls for coating techniques that circumvent the drawbacks of the well-established physical vapor deposition. The atomic layer deposition method (ALD) allows depositing films on the nanometer scale conformally both on three-dimensional objects as well as on large-area substrates. The present work therefore is concerned with the development of an ALD process to grow copper oxide films based on the metal-organic precursor bis(trin- butylphosphane)copper(I)acetylacetonate [({sup n}Bu{sub 3}P){sub 2}Cu(acac)]. This liquid, non-fluorinated {beta}-diketonate is brought to react with a mixture of water vapor and oxygen at temperatures from 100 to 160 C. Typical ALD-like growth behavior arises between 100 and 130 C, depending on the respective substrate used. On tantalum nitride and silicon dioxide substrates, smooth films and selfsaturating film growth, typical for ALD, are obtained. On ruthenium substrates, positive deposition results are obtained as well. However, a considerable intermixing of the ALD copper oxide with the underlying films takes place. Tantalum substrates lead to a fast self-decomposition of the copper precursor. As a consequence, isolated nuclei or larger particles are always obtained together with continuous films. The copper oxide films grown by ALD can be reduced to copper by vapor-phase processes. If formic acid is used as the reducing agent, these processes can already be carried out at similar temperatures as the ALD, so that agglomeration of the films is largely avoided. Also for an integration with subsequent electrochemical copper deposition, the combination of ALD copper and ruthenium proves advantageous, especially with respect to the quality of the electroplated films and their filling behavior in interconnect structures. Furthermore, the ALD process developed also bears potential for an integration with carbon nanotubes. (orig.)}
place = {Germany}
year = {2010}
month = {May}
}