Characterization of thin copper films grown via chemical vapor deposition using liquid coinjection of trimethylvinylsilane and (hexafluoroacetylacetonate) Cu (trimethylvinylsilane)

• Published in: Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Vol. 13; no. 1; pp. 130 - 136
• Main Authors: Parmeter, J. E., Petersen, G. A., Smith, P. M., Apblett, C. A., Reid, J. S., Norman, J. A. T., Hochberg, A. K., Roberts, D. A., Omstead, Thomas R.
• Format: Journal Article
• Language: English
• Published: United States 01-01-1995
• Subjects: ANNEALING; CHEMICAL COATING; CHEMICAL VAPOR DEPOSITION; COPPER; DENSITY; DEPOSITION; DIMENSIONS; ELECTRIC CONDUCTIVITY; ELECTRICAL PROPERTIES; ELEMENTS; GRAIN SIZE; HEAT TREATMENTS; IMPURITIES; MATERIALS SCIENCE; METALS; MICROSTRUCTURE; ORGANIC COMPOUNDS; ORGANIC SILICON COMPOUNDS; ORGANOMETALLIC COMPOUNDS; PHYSICAL PROPERTIES; SIZE; SURFACE COATING; TEMPERATURE RANGE; TEMPERATURE RANGE 0400-1000 K; THICKNESS; THIN FILMS; TRANSITION ELEMENTS 360102 > Metals & Alloys > Structure & Phase Studies; CHEMICAL VAPOR DEPOSITION; ORGANOMETALLIC COMPOUNDS; ORGANIC SILICON COMPOUNDS; THIN FILMS; ANNEALING; GRAIN SIZE; COPPER; IMPURITIES; DENSITY; Cu; ELECTRIC CONDUCTIVITY; THICKNESS; TEMPERATURE RANGE 0400−1000 K
• ISSN: 0734-211X; 1520-8567; 2327-9877
• DOI: 10.1116/1.588005

We have developed a technique recently for copper chemical vapor deposition utilizing direct liquid coinjection of trimethylvinylsilane (TMVS) and the copper (I) precursor (hexafluoroacetylacetonate) Cu (TMVS). We present here an investigation of the properties of copper films deposited using this technique. The films were grown on Si3N4 substrates at temperatures in the range of 220–250 °C and characterized using several experimental techniques, with an emphasis placed on factors influencing copper film resistivity. The average as‐deposited film resistivity is 1.86 μΩ cm; this value is reduced to 1.82 μΩ cm when the effects of surface scattering are taken into account. The resistivity is essentially independent of film thickness for thicknesses between 0.2 and 3.5 μm, and is reduced by less than 0.05 μΩ cm by annealing at 400–600 °C in vacuum. The total impurity content of the films is approximately 100 parts per million. The film density is 97±2% of the bulk copper value. The average grain size increases with film thickness and falls in the range of 0.5–1.5 μm. Morphological defects are the main cause of the resistivities (after adjusting for surface scattering) being approximately 0.14 μΩ cm above the bulk copper value (1.68 μΩ cm). Comparison of thickness and resistivity measurements for rough as‐deposited films and smooth chemical‐mechanical polished films shows that the surface roughness causes surface profilometry to overestimate the thicknesses of the unpolished films by approximately 1300 Å. This effect can lead to both artificially high resistivity values and a false dependence of resistivity on film thickness if profilometry measurements for the unpolished films are not properly corrected.