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The changes in diffusion rates of Sb, As, and P resulting from nitridation of SiO2 and direct nitridation of the silicon surface in NH3 ambient at 1100 °C are studied for times ranging from 7 min to 4.5 h. From analysis of these data we conclude that P must diffuse almost entirely by an interstitialcy mechanism at this temperature, and that previous formulations of dopant diffusion under nonequilibrium conditions may not be complete. We also determine that the effects seen during direct nitridation are better explained by a pure vacancy injection process than a pure self-interstitial depletion process, contrary to previous assertions by us and others.

The use of copper interconnects enables higher speed, enhanced electromigration lifetime reliability, reduced power consumption, and ultimately reduced manufacturing cost for silicon integrated circuits. The formation of planarized inlaid copper interconnects requires sequential deposition of a continuous diffusion barrier layer followed by copper seed/fill deposition and chemical-mechanical polishing (CMP). In this article we present a vacuum-integrated cluster tool technology for deposition of a TaN barrier and copper seed/fill layers using metalorganic chemical vapor deposition (MOCVD). The MOCVD-based TaN layers deposited at substrate temperatures below 430 °C are highly conformal, have 800–1000 μΩ cm resistivity, have satisfactory adhesion to silicon dioxide, and provide superior diffusion barrier properties compared to Ta and TaN layers deposited by physical vapor deposition. The cluster MOCVD-Cu process is capable of depositing conformal and low-resistivity copper seed layers with satisfactory adhesion for subsequent copper filling by either electrochemical deposition or MOCVD. The cluster MOCVD technology has been used to fabricate inlaid copper metallization lines and plugs based on CMP damascene processing. The combination of MOCVD TaN and MOCVD copper is expected to provide an extendable multigenerational copper metallization solution for 0.18–0.10 μm technology nodes and beyond.

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A wafer temperature control system is developed for rapid thermal processing (RTP) semiconductor manufacturing equipment. The control algorithm is based on a physical model describing the heat transfer effects in advanced RTP equipment. A model identification procedure is proposed to estimate the uncertain parameters of the model from a set of experiments. Through singular value analysis, the impact of equipment design on feedback controller development is studied. An internal model control (IMC) design methodology is used to develop a low-order multivariable feedback control algorithm. The feedback controller is coordinated with additional modules including feedforward control and gain scheduling to achieve improved performance and flexibility. The algorithms are applied to three different multizone RTP systems. Temperature controlled ramps are demonstrated from 20 to 900~ at 45~ with less than +_5~ during the ramp at high temperatures and less than +-I~ average nonuniformity during steady state as measured by three radially distributed temperature sensors.Rapid thermal processing (RTP) is a semiconductor manufacturing technology that performs single-wafer thermal processing operations including annealing, oxidation, and chemical vapor deposition./3 In order to achieve slip-free and uniform processing, it is necessary to maintain a uniform temperature distribution over the wafer during both steady-state and transient (fast ramping of wafer temperature) situations. Furthermore, this uniform distribution must be achieved for a range of operating conditions including different pressures, gasses, and processing temperatures. In this manner, an RTP system is available for flexible manufacturing applications that can adapt and optimize to changes in the processing specifications.Recent innovations in the design of RTP systems have provided the ability for achieving temperature uniformity over a range of processing conditions. The basic requirement of the equipment is the ability to vary the spatial energy flux distribution radiating to the wafer as the necessities for wafer temperature uniformity change as a function of operating conditions. To achieve this requirement, one approach involves the use of multiple concentric circular rings (or zones) of lamps that can be manipulated independently.In this paper, we describe the development of a multivariable automatic control system for multizone RTP systems. The controller is used to compute the set of powers to the lamp zones in response to feedback information provided by an array of sensors measuring temperature at multiple points on the wafer. The objective of the control system is to minimize temperature nonuniformity while tracking a desired temperature trajectory.The control strategy is based on a first-principles model of the energy transport mechanisms in RTP systems. The nonlinear model is developed specifically for the purpose of control design as opposed to ones developed for simulation applications ~'~ or developed from a black-box approach. 8-n The model re...

The surface plasmon spectroscopy (SPS) technique is used in the characterization of dielectric-coated metal mirrors. Experiments performed on a MgF(2)-coated aluminum mirror indicate good agreement between SPS and ellipsometry techniques for the determination of coating thickness. In addition, the optical constants of aluminum obtained from the same experiment agree well with values presented in the literature. Advantages of SPS are that it is a simple procedure providing a high degree of accuracy, and only a single measurement is required to yield both the film thickness and the complex permittivity of the substrate.

The vapor-phase hydrogen fluoride etch of oxides and nitride of silicon have been studied. A new mode of oxide selectivity, not possible with aqueous HF-based processes, gives rise to novel processes with practical applications. The inherent cleanliness and the resulting four to five times improvement in the electrical stress endurance of thin oxides make the vapor-phase process a viable substitute for the traditional processes based on aqueous HF.