This work aims to systematically gain an understanding of the effects of multilayer patterns on wafer temperature uniformity during rapid thermal processing, and explore possible solutions to the problem. Steady state and transient wafer temperature distributions are simulated by combining a detailed reactor transport model with multilayer electromagnetic theory to predict wafer radiative properties. A generic axisymmetric RTP system with single-side illumination is used as a testbed to explore pattern effects for a simulated source/drain implant anneal.

The directional reflectance and approximate emissivity of rough silicon wafers were measured by reflection measurements using a single point detector and a broad area illumination source. Experiments were also performed to determine the cone angle of the incident light required to properly measure the emissivity of rough backsides. Based on surface roughness parameters acquired with an Atomic Force Microscope, reflectance calculations were performed within the framework of the Beckmann-Spizzichino model. The results are qualitatively consistent with experimental observations.

A highly flexible Rapid Thermal Multiprocessing (RTM) reactor is described. This flexibility is the result of several new innovations: a lamp system, an acoustic thermometer and a real-time control system. The new lamp has been optimally designed through the use of a “virtual reactor” methodology to obtain the best possible wafer temperature uniformity. It consists of multiple concentric rings composed of light bulbs with horizontal filaments. Each ring is independently and dynamically controlled providing better control over the spatial and temporal optical flux profile resulting in excellent temperature uniformity over a wide range of process conditions. An acoustic thermometer non-invasively allows complete wafer temperature tomography under all process conditions - a critically important measurement never obtained before. For real-time equipment and process control a model based multivariable control system has been developed. Extensive integration of computers and related technology for specification, communication, execution, monitoring, control, and diagnosis demonstrates the programmability of the RTM.

Measurement of resistance in-situ during rapid thermal annealing is a powerful technique for process characterization and optimization. A major advantage of in-situ resistance measurements is the very rapid process learning. With silicides, in-situ resistance measurements can quickly determine an appropriate thermal process in which a low resistance silicide phase is formed without the agglomeration or inversion of silicide/polycrystalline silicon structures. One example is an optimized two step anneal for CoSi2 formation which was developed in less than one clay. Examples of process characterization include determining the phase formation kinetics of TiSi2 (C49 and C54), Co2Si, and CoSi2 using in-situ ramped resistance measurements. The stability of TiSi2 or CoSi2/poly-Si structures has also been characterized by isothermal measurements. Resistance measurements have been made at heating rates from 1 to 100°C/s and temperatures up to 1000°C. The sample temperature was calibrated by melting Ag, Al, or Au/Si eutectics.

Starting with basic physical radiation principles and with Beers law formulas for the radiation characteristics of arrays of pointlike radiation sources and tubular halogen lamps are analytically derived. Different arrangements of tubular halogen lamps are considered and compared with each other. Homogeneity criteria are worked out and it is demonstrated that the minimum homogeneity distance between a plane in which all filaments are arranged parallel to each other, and an object depends only on the distance between two neighbouring filaments and thus can be given by a simple number. Interesting aspects for RTP equipment manufacturers as well as for users are demonstrated by comparing different lamp arrangements with each other: In crossed lamp fields latticelike inhomogeneity knots arise in the object plane at points where the lamp filaments of the upper and the lower lamp plane cross. If the filaments are arranged parallel to each other in two filament planes, very homogeneous results are obtained when the filaments of the two planes interlace.

The cost of a fabrication line, such as one in a semiconductor house, has increased dramatically over the years, and it is possibly already past the point that some new start-up company can have sufficient capital to build a new fabrication line. Such capital-intensive manufacturing needs better utilization of resources and management of equipment to maximize its productivity. In order to maximize the return from such a capital-intensive manufacturing line, we need to work on the following: 1) increasing the yield, 2) enhancing the flexibility of the fabrication line, 3) improving quality, and finally 4) minimizing the down time of the processing equipment. Because of the significant advances now made in the fields of artificial neural networks, fuzzy logic, machine learning and genetic algorithms, we advocate the use of these new tools in manufacturing. We term the applications to manufacturing of these and other such tools that mimic human intelligence neural manufacturing. This paper describes the effort at the Lawrence Livermore National Laboratory (LLNL) [1] to use artificial neural networks to address certain semiconductor process modeling, monitoring and control questions.*

A new approach to semiconductor manufacturing is necessary to decouple end product cost from factory volume. The economy of scale model for manufacturing semiconductor integrated circuits is leading to factories that cost in excess of $1 billion and with costs anticipated to increase nonlinearly. Perhaps of greater concern is that process development and integration costs are of the same magnitude. The Advanced Research Projects Agency (ARPA) has funded several stand-alone research programs to explore new ways of designing and fabricating leading-edge semiconductors. The next steps are to tightly couple design and manufacturing through powerful new frameworks and embedded intelligence with tools. This new manufacturing capability based on flexible, intelligent equipment coupled to a powerful design framework could lead to a leading-edge manufacturing capability, but at a fraction of the cost of a conventional factory. Furthermore, this manufacturing model supports innovation and could lead to a new generation of ICs and systems. The key elements necessary to enable this new semiconductor fabrication environment is described.

A concurrent-engineering approach is applied to the development of an axisymmetric rapidthermal-processing (RTP) reactor and its associated temperature controller. Using a detailed finiteelement thermal model as a surrogate for actual hardware, we have developed and tested a multi-input multi-output (MIMO) controller. Closed-loop simulations are performed by linking the control algorithm with the finite-element code. Simulations show that good temperature uniformity is maintained on the wafer during both steady and transient conditions. A numerical study shows the effect of ramp rate, feedback gain, sensor placement, and wafer-emissivity patterns on system performance.

The Magnetron Sputter Ion Plating (MSIP) technology has been applied in a wide range of modem technological fields, due to the virtually unlimited potential of coating and substrate materials. However, up to now, the development of optimization has been depending mainly on empiricism and experiments.

Energies and the directions of the particles sputtered with various ejection angles and initial energies from the target surface are changed due to collisions with gas atoms during their movement within the sputtering chamber. Therefore the particles have a distribution of incident energies and angles which have a great influence on structure and properties of thin film coatings. This paper describes computer investigations to simulate the motions of the particles from target to substrate using a Monte-Carlo method and a binary collision approximation. The applied model takes into account non-uniform sputtering effects of the target in the MSIP process due to the magnetic field and the erosion zone.

The Direct Simulation Monte Carlo (DSMC) method is applied to the problem of pulsed laser deposition in both ID and 2D axisymmetric simulations. A source of target atoms expands into a cylindrical volume containing a background gas at room temperature and pressures up to 100 mTorr in the presence of a diffusely reflecting substrate. At regular intervals, the density and temperature of each species are computed. Particle flux and energy per particle incident on the substrate are also monitored as functions of time. The simulation results qualitatively compare, well with experimental plume diagnostics, with measured film growth rates as a function of background gas pressure, and with measured changes in film growth stoichiometry resulting from the introduction of a background gas into a two-component PLD system.

Collimated sputtering has been successful in providing good contact barriers for sub-half micron contacts with aspect ratios of 3 and greater. This approach does present drawbacks however, particularly in terms of reduced deposition rates and degraded film uniformity. The flux collected on the collimator leads to closing off of the cells, further reducing deposition rate on the wafer and limiting the life of the collimator. This paper demonstrates simulation of the filling of the collimator with different system configurations and pressures using the SIMSPUD vapor transport and SIMBAD thin film growth simulators. The model can determine collimator filling uniformity, blanket film uniformity, angular distribution of collimated sputter flux, and lifetime of the collimator. Given the target erosion profile, system geometry, and deposition rate, collimator lifetime can be predicted. The model indicates that for a 300 mm diameter source a drop in operating pressure from 0.67 Pa to 0.27 Pa has little effect on collimator life in terms of kWh, while increasing collimator life in terms of wafers by about 50%. The increase in the number of wafers processed comes at the expense of a small loss of uniformity.