Roderick Craig Mosely

Resistivity reduction and chemical stabilization of organometallic chemical vapor deposited titanium nitride by nitrogen rf plasma

In situ, nitrogen rf plasma treatment of organometallic chemical vapor deposited (OMCVD) TiN, synthesized by thermal decomposition of tetrakis(dimethylamido) titanium, yielded films with low resistivity and enhanced chemical stability. A sequential OMCVD‐plasma treatment process allowed deposition of films with bulk resistivity as low as 400 μΩ cm. The nitridation resulted in reduction of the carbon concentration in the films, and crystallization of TiN. The composition and electrical properties of the nitridized films were found to be stable upon air exposure. The films possess excellent step coverage (≳70% in 0.35 μm device structures with aspect ratio ∼3) and low defect density (∼0.06 cm−2 for defect size ≥0.2 μm).

Nucleation and growth of CVD Al on different types of TiN

Abstract The deposition of Al by CVD on top of a Ti/TiN liner is a very promising approach for filling gaps with a high aspect ratio. In this work we have studied the nucleation and growth of CVD Al and its bulk properties as a function of the type of TiN used. For a given type of TiN we deposited films over a wide range of thickness (5–300 nm). The depositions were carried out in a cluster tool (Endura™) where in some cases we deliberately allowed for a vacuum break prior to the Al deposition. Auger electron spectroscopy was used to measure the amount of Al deposited, thus yielding the kinetics of the Al growth. X-ray diffraction was used to determine the preferred orientation of the Al, which is important for electromigration resistance. The microstructure was studied by scanning and transmission electron microscopy and atomic force microscopy. We found that air exposure affects the nucleation, the rate of growth at the early stages, and the resultant morphology. A correlation exists between the nucleation stages of the growth and the bulk properties.

Barrier crystallographic texture control and its impact on copper interconnect reliability

The impacts of barrier micro-structure on Cu seed and electro copper plating (ECP) film have been investigated in terms of seed sheet resistance (R/sub s/) stability, crystal orientation, and wetting properties; ECP film surface morphology and CMP defects. We have studied the effect of these parameters using 4-point probe, X-ray diffraction (XRD), scanning electron microscopy (SEM), and SEM vision. We also studied barrier impact on via resistance and interconnect reliability using E-test measurement and stress migration test. It was found that barrier layer micro-structure can manipulate seed layer and ECP film properties, which affect E-test performance. The seed layer deposited on highly <110>-oriented /spl alpha/-Ta underlayer shows better Cu <111> orientation, resulting in a seed with stable R/sub s/, better wetting properties, smoother ECP film, and lower defects. In addition, it shows lower via resistance and better interconnection reliability.

Void-free chemically vapor-deposited aluminum dual inlaid metallization schemes for ultra-large-scale-integrated via and interconnect applications

This letter reports an investigation of two unique dual inlaid metallization approaches with low pressure chemical vapor deposition (LPCVD) of aluminum (Al) for sub-0.35 μm ultra-large-scale-integration interconnect technology: (1) warm Al/CVD Al/coherent (coh.) PVD Al/coh. PVD Ti and (2) warm PVD Al/CVD Al/coh. PVD Ti or Al/selective CVD Al. The integration of thin coh. PVD Al, deposited with a physical collimator or a variation of ionized metal plasma technique, was found to be the unique and simple solution in providing void-free via and interconnect structures, which have not been reported elsewhere. Excellent electrical and electromigration results have been obtained.

Cu barrier/seed technology development for sub-0.10 micron copper chips

Advanced PVD technologies have been reviewed for copper barrier-seed applications for different device nodes. Each new device generation requires improved step coverage and reduced overhang. With each shift in deposition technology, there have been process and hardware advancements to meet decreasing feature sizes and increasing aspect ratios. The extension of PVD to 0.1 /spl mu/m has delayed the need for a CVD barrier and seed solution. However, PVDs limitations in step coverage, and the introduction of porous low-k dielectrics may necessitate a transition to CVD barriers below 0.10 /spl mu/m. The process integration of SIP-Cu and a proven barrier solution TDMAT (tetrakis dimethyl amino titanium)-based CVD TiSiN is also discussed in this paper.