Robert W. Fiordalice

Thin film properties of low‐pressure chemical vapor deposition TiN barrier for ultra‐large‐scale integration applications

Titanium nitride films deposited by low‐pressure chemical vapor deposition (LPCVD) on Si(100) using TiCl4 and NH3 as reactants, were investigated as a function of deposition temperature between 400 and 700 °C. LPCVD TiN depositions were carried out in a rapid thermal chemical vapor deposition system with a total deposition pressure of 155 mTorr. Stoichiometric TiN films were formed regardless of the deposition temperature and composition was uniform across the entire film. Depending on deposition temperature, varying amounts of chlorine (Cl) and oxygen (O) impurities are found in the TiN films. Films deposited at lower temperatures (400 and 550 °C) contained more than 5 at. % Cl, while the films produced at 700 °C contained as little as 1 at. % Cl. For the films deposited at 650 and 700 °C, the bulk of the TiN films is oxygen‐free. LPCVD TiN deposition rates of 400 A/min with no appreciable incubation time were routinely achieved. The LPCVD TiN deposition process is surface reaction controlled with an act...

TiNCl formation during low‐temperature, low‐pressure chemical vapor deposition of TiN

We report for the first time the existence of the titanium nitride chloride (TiNCl) compound in low‐temperature (400 °C) low‐pressure chemical vapor deposition (LPCVD) TiN films deposited using TiCl4/NH3 chemistry. Thin‐film x‐ray diffraction and Auger electron spectroscopy was used in the film characterization. Physical, chemical, and electrical properties of the resulting low‐temperature LPCVD TiN films are discussed.

Orientation Control of Chemical Vapor Deposition TiN Film for Barrier Applications

A chemical vapor deposition (CVD) TiN film with preferred crystal orientation was developed using an in situ two-step process scheme. A thin CVD TiN layer is deposited first under low TiCl 4 partial pressure. This layer has poor step coverage, but acts as a crystallographic seed layer for the subsequent CVD TiN layer deposited under high TiCl 4 partial pressure. This layer, deposited sequentially without breaking vacuum, shows a TiN preferred orientation when deposited under these conditions and provides excellent step coverage. This CVD TiN layer stack has shown both excellent diffusion barrier properties to CVD Cu, and improved electromigration reliability relative to conventional CVD TiN using TiCl 4 /NH 3 chemistry.

Nucleation and growth of chemical vapor deposition TiN films on Si (100) as studied by total reflection x‐ray fluorescence, atomic force microscopy, and Auger electron spectroscopy

We report for the first time the characteristics of the early growth of chemical vapor deposition (CVD) TiN films on Si (100) in the surface reaction limited regime, using total reflection x‐ray fluorescence (TXRF), atomic force microscopy (AFM), and Auger electron spectroscopy (AES). Small amounts of CVD TiN from TiCl4 and NH3 reactants were deposited on Si (100) at 650 °C using a rapid thermal CVD system, at a total pressure of 155 mTorr. We examined these small amounts of CVD TiN by introducing TXRF as a tool for observing the initial stages of growth, and AFM for characterizing changes in the overall surface morphology. The nucleation and growth of the resulting CVD TiN films as determined by TXRF, AFM, and AES will be discussed.

Ti/borophosphosilicate glass interfacial reactions and their effects on adhesion

The interfacial reaction of sputtered Ti films with borophosphosilicate glass (BPSG) sublayers has been studied using primarily Auger electron spectroscopy depth profiling techniques. Thin interfacial layers formed during rapid thermal annealing in N2 ambients were studied as a function of temperature, time, BPSG composition, and sublayer preclean treatment. A P‐rich (phosphide) layer was found to accumulate at the Ti/BPSG interface during the reactions and in so doing inhibited the Ti/SiO2 reduction reaction. B accumulated only when the consumption of the entire Ti film neared completion. In some cases, adhesion failures could be generated following the deposition of an Al metallization over the reacted Ti/BPSG films. These failures were found to occur between the P‐rich (phosphide) interfacial layer and the BPSG sublayer and could be prevented by backsputtering the BPSG prior to Ti depositon.

A Low Temperature Collimated Titanium Deposition Process

By depositing collimated titanium at near room temperature, a preferred (002) oriented Ti film is formed. These (002) Ti films showed uniform grain size distributions and a smooth surface topography. In contrast, collimated Ti using conventional deposition temperatures (175°C) results in a (101) Ti and (002) Ti mixed orientation, bimodal grain size distributions, and a rough surface topography. The measured resistivity of the low temperature film is 63 μΩ cm which is close to that of 60 μΩ cm, attained by collimated processing at elevated temperatures. The film stress for the low temperature collimated Ti layer is 1.0 E9 dynes/cm 2 compressive, while it is 1.3 E9 dynes/cm 2 tensile for the conventional collimated Ti layers. Low temperature collimated Ti deposited as a contact layer at the bottom of deep contacts with an aspect ratio of 3:1 showed excellent bottom surface coverage. In addition, lower via resistance values have been obtained using the low temperature collimated Ti process.

Thin Film Properties of LPCVD TiN Barrier for Silicon Device Technology

Thin film properties of LPCVD TiN barriers deposited on Si(100), using TiCl 4 and NH 3 as reactants, were investigated as a function of deposition temperature between 400 °C and 700 °C. The TiN film chemistry and film composition were studied by AES and RBS techniques, while the microstructural properties (grain size, lattice parameter and texture) were evaluated by XRD. The TiN deposition rates and film resistivities were also determined. Finally the film properties of the TiN barriers as determined by surface analysis were related to the process parameters.

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.

A low temperature CVD Al plug and interconnect process for 0.25 /spl mu/m metallization technologies

This report describes the development and integration of a blanket CVD aluminum module into advanced microprocessor devices. The in situ deposition of sputter deposited nucleation layers and PVD Al overlayers has been demonstrated to improve film morphology and ultimate reliability. Full integration into 5 level metal microprocessors has been achieved.

PVD Ti-Si-N Films Process Development for Copper Interconnect Applications

A process has been developed for the deposition of amorphous Ti-Si-N films using reactive ion sputtering of a TiSi target. The Ti-Si-N films have been extensively characterized over a wide range of process parameters. Resistivities of the films less than 300 μΩ-cm have been achieved. Stress measurements on Ti-Si-N films indicate that the film stress changes from tensile to compressive as the nitrogen composition is increased. Near-zero film stresses were achieved by choice of optimum nitrogen N 2 flow. SIMS analysis of Cu diffusion through blanket PVD Ti-Si-N (300A) after an anneal at 390°C/3 hour showed a near overlap of the Cu profile compared to the profile of an unannealed SiO 2 /PVD Ti-Si-N /Cu film stack, indicating that the Cu did not diffuse significantly through the barrier after anneal. Low contact resistance (0.8 Ω) and low ( −11 A) leakage were obtained using a dual inlaid structure with a 300 A Ti-Si-N processed with optimized conditions. These results showed that Ti-Si-N could be used as a potential barrier for copper metallization.