Preparation and analysis of amorphous carbon films deposited from (C6H12)/Ar/He chemistry for application as the dry etch hard mask in the semiconductor manufacturing process

Abstract

Amorphous carbon layers (ACL) were deposited on Si (100) wafers by plasma enhanced chemical vapor deposition (PECVD) by using 1-hexene (C6H12) as a carbon source for dry etch hard mask of semiconductor devices manufacturing process. The deposition characteristics and film properties were investigated by means of ellipsometry, Raman spectroscopy, X-ray photo electron spectroscopy (XPS) and stress analysis. Hardness, Young's modulus, and surface roughness of ACL deposited at 550 degrees C were investigated by using nano-indentation and AFM. The deposition rate was decreased from 5050 angstrom/min to 2160 angstrom/min, and dry etch rate was decreased from 2090 angstrom/min to 1770 angstrom/min, and extinction coefficient was increased from 0.1 to 0.5. Raman analysis revealed a higher shift of the G-peak and a lower shift of the D-peak and the increase of I(D)/I(G) ratio as the deposition temperature was increased from 350 degrees C to 550 degrees C. XPS results of ACL deposited at 550 degrees C revealed a carbon 1s binding energy of 284.4 eV. The compressive film stress was decreased from 2.95 GPa to 1.28 GPa with increasing deposition temperature. The hardness and Young's modulus of ACL deposited at 550 degrees C were 5.8 GPa and 48.7 GPa respectively. The surface roughness RMS of ACL deposited at 550 degrees C was 2.24 angstrom, and that after cleaning in diluted HF solution (H2O:HF = 200:1), SC1 (NH4OH:H2O2:H2O = 1:4:20) solution, and sulfuric acid solution (H2SO4:H2O2= 6:1) was 2.28 angstrom, 2.30 angstrom and 7.34 angstrom. respectively. The removal amount of ACL deposited at 550 degrees C in diluted HF solution, SC1 solution and sulfuric acid solution was 6 angstrom, 36 angstrom and 110 angstrom, respectively. These results demonstrated the viability of ACL deposited by PECVD from C6H12 at 550 degrees C for application as the dry etch hard mask in fabrication of semiconductor devices. (C) 2011 Elsevier B.V. All rights reserved.