skip to main content

Title: Quantum cascade laser based monitoring of CF{sub 2} radical concentration as a diagnostic tool of dielectric etching plasma processes

Dielectric etching plasma processes for modern interlevel dielectrics become more and more complex by the introduction of new ultra low-k dielectrics. One challenge is the minimization of sidewall damage, while etching ultra low-k porous SiCOH by fluorocarbon plasmas. The optimization of this process requires a deeper understanding of the concentration of the CF{sub 2} radical, which acts as precursor in the polymerization of the etch sample surfaces. In an industrial dielectric etching plasma reactor, the CF{sub 2} radical was measured in situ using a continuous wave quantum cascade laser (cw-QCL) around 1106.2 cm{sup −1}. We measured Doppler-resolved ro-vibrational absorption lines and determined absolute densities using transitions in the ν{sub 3} fundamental band of CF{sub 2} with the aid of an improved simulation of the line strengths. We found that the CF{sub 2} radical concentration during the etching plasma process directly correlates to the layer structure of the etched wafer. Hence, this correlation can serve as a diagnostic tool of dielectric etching plasma processes. Applying QCL based absorption spectroscopy opens up the way for advanced process monitoring and etching controlling in semiconductor manufacturing.
Authors:
; ; ;  [1] ; ;  [2] ;  [3]
  1. Leibniz Institute for Plasma Science and Technology (INP Greifswald), Felix-Hausdorff Str. 2, 17489 Greifswald (Germany)
  2. Fraunhofer Institute for Electronic Nano Systems, Technologie-Campus 3, 09126 Chemnitz (Germany)
  3. GLOBALFOUNDRIES Dresden Module One LLC and Co. KG, Wilschdorfer Landstr. 101, 01109 Dresden (Germany)
Publication Date:
OSTI Identifier:
22415113
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARBENES; CARBON COMPOUNDS; CONCENTRATION RATIO; DIELECTRIC MATERIALS; ETCHING; FLUORINE COMPOUNDS; HYDROGEN COMPOUNDS; MINIMIZATION; OXYGEN COMPOUNDS; PLASMA; SEMICONDUCTOR LASERS; SEMICONDUCTOR MATERIALS; SILICON COMPOUNDS