Thomas R. Omstead

Chemical additives for improved copper chemical vapour deposition processing

Abstract Techniques for improved copper chemical vapour deposition (CVD) processing by the addition of trimethylvinylsilane (tmvs) and hexafluoroacetylacetone (Hhfac) during copper deposition from the volatile liquid precursor Cu(hfac)(tmvs) are described. The tmvs enables stable high vaporization rates of precursor by direct liquid injection and the Hhfac permits higher deposition rates of smoother copper films. The resistivity of the copper films averages approximately 1.8 μΩcm as deposited. Combined together, these results mark an important advance toward a manufacturable copper CVD process.

Enhanced Chemical Vapor Deposition of Copper from ( hfac ) Cu ( TMVS ) Using Liquid Coinjection of TMVS

A direct liquid connection system has been applied to the chemical vapor deposition of copper using the commercially available Cu(I) precursor (hfac)Cu(TMVS), where hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate and TMVS = trimethylvinyl-silane. Precursor delivery was enhanced through the use of a coinjection system wherein additional TMVS was mixed with tire copper precursor before injection into the vaporization chamber. The results reported here demonstrate the capability of depositing blanket cooper for high purity (on the order of 99.99% copper) and low resistivity (1.85 {+-} 0.1 {mu}{Omega}-cm). These copper films have been deposited at rates up to and exceeding 1,500 {angstrom}/min. The effects of temperature and carrier gas on deposition rate and resistivity are examined. The as-deposited films demonstrate and dependence of grain size with thickness and little structural or morphological change with annealing. This study suggests that liquid coinjection is an effective method for enhancing deposition rates and for producing high quality copper films from copper(I) precursors.

Chemical vapor deposition of copper from CuI hexafluoroacetylacetonate trimethylvinylsilane for ultralarge scale integration applications

In this article, the authors report the results of a study aimed at optimizing a manufacturable thermal copper‐chemical vapor deposition process, using (tmvs) CuI (hfac) as the source, where tmvs=trimethylvinylsilane and hfac=hexafluoroacetylacetonate, and establishing associated material and process characteristics and performance. This study employed a two‐stage design of experiments approach in conjunction with actual deposition runs on unpatterned silicon (Si) and titanium nitride (TiN) surfaces, as well as SEMATECH patterned TiN structures with feature sizes as small as 0.30 μm with aspect ratio 6:1. All samples were analyzed by Auger electron spectroscopy, Rutherford backscattering, four‐point resistivity probe, and cross‐section scanning electron microscopy. The results of these analyses showed that precursor concentration, substrate temperature, and in situ predeposition substrate surface plasma treatment play a key role in achieving good conformality and complete filling at high growth rates in a...

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

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 increase...

Single-Wafer Process Integration and Process Control Techniques

State-of-the-art semiconductor technologies employ thermal processing steps for various anneal, oxidation, and chemical vapor deposition (CVD) processes. Most of these fabrication processes have been dominated by hot-wall batch furnaces. Many other unit processes, however, are already performed in single-wafer processors. These include plasma etch, plasma-enhanced dielectric deposition, metal deposition, ion implantation, and microlithography. The advantages of single-wafer processing have been discussed elsewhere [1]. They have been primarily related to enhanced control of processing individual wafers, particularly as the diameter of silicon wafers has increased to 200 mm.