Numerical Modeling of Radiative Properties of Patterned Wafers with Sub-Micron Features

1996 ◽  
Vol 429 ◽  
Author(s):  
Jeffrey B. Hoppert ◽  
Ioannis N. Miaoulis ◽  
Peter Y. Wong

AbstractDecreasing feature sizes in the microelectronics industry have led to numerous processing problems with thin film semiconductors. Non-uniform temperature distributions, due to microscale radiation effects on the radiative properties of the thin film structures, are responsible for wafer defects. These microscale radiation effects become significant as pattern spacing and film thicknesses reach the same order of magnitude as the wavelengths of the heat-source radiation. A numerical model has been developed in which normal emissivities for patterned wafers are calculated, using an effective index of refraction technique. In this study various patterns at temperatures critical to the thermal processing are examined.

1994 ◽  
Vol 342 ◽  
Author(s):  
Peter Y. Wong ◽  
Ioannis N. Miaoulis

ABSTRACTMicroscale radiation effects are responsible for the dependence of absorption and temperature distributions on the geometry of the layering structures and the spectral characteristics of the heat source. The effect of patterned wafers, which may contain several different structures and materials, on the wafer absorption characteristics are investigated for rapid thermal processing. A numerical model to determine the thermal radiative absorptivity of the wafer for different structures and materials is presented for different heating conditions. The resulting transient effects are determined numerically for different rapid thermal processes. The changes in radiative properties for rapid thermal annealing and chemical vapor deposition are investigated for patterned wafers.


1995 ◽  
Vol 387 ◽  
Author(s):  
Peter Y. Wong ◽  
Ioannis N. Miaoulis ◽  
Cynthia G. Madras

AbstractTemperature measurements and processing uniformity continue to be major issues in Rapid Thermal Processing. Spatial and temporal variations in thermal radiative properties of the wafer surface are sources of non-uniformities and dynamic variations. These effects are due to changes in spectral distribution (wafer or heat source), oxidation, epitaxy, silicidation, and other microstructural transformations. Additionally, other variations are induced by the underlying (before processing) and developing (during processing) patterns on the wafer. Numerical simulations of Co silicidation that account for these factors are conducted to determine the radiative properties, heat transfer dynamics, and resultant processing uniformity.


1993 ◽  
Vol 303 ◽  
Author(s):  
Peter Y. Wong ◽  
Christopher K. Hess ◽  
Ioannis N. Miaoulis

ABSTRACTThe individual film thicknesses of multilayered structures processed by rapid thermal processing are of the same order as the wavelengths of the incident radiation. This induces optical interference effects which are responsible for the strong dependency of surface reflectivity, emissivity, and temperature distributions on the geometry of the layering structures, presence of patterns, and thickness of the films. A two-dimensional, finitedifference numerical model has been developed to investigate this microscale radiation phenomena and identify the critical processing parameters which affect rapid thermal processing of multilayer thin films. The uniformity of temperature distributions throughout the wafer during rapid thermal processing is directly affected by incident heater configurations, ramping conditions, wafer-edge effects, and thin-film layering structure. Results from the numerical model for various film structures are presented for chemical vapor deposition of polycrystalline silicon over oxide films on substrate. A novel technique using an edge-enhanced wafer which has a different film structure near its edge is presented as a control over the transient temperature distribution.


1996 ◽  
Vol 429 ◽  
Author(s):  
Jeffrey P. Hebbi ◽  
Klavs F. Jensen

AbstractMultilayer patterns can lead to temperature non-uniformity and undesirable levels of thermal stress in silicon wafers during rapid thermal processing (RTP). Thermal stress can, in turn, cause problems such as photolithography overlay errors and degraded device performance through plastic deformation. In this work, the temperature and stress fields in patterned wafers are simulated using detailed finite-element based reactor transport models coupled with electromagnetic theory for predicting radiative properties of multilayers. The temperature distributions are then used to predict the stress fields in the wafer and the onset of plastic deformation. Results are presented for two generic two-dimensional axi-symmetric reactors employing single and double side illumination. The effect of patterns and processing parameters are explored, and strategies for avoiding pattern induced plastic deformation are evaluated.


1997 ◽  
Vol 470 ◽  
Author(s):  
D. P. DeWitt ◽  
F. Y. Sorrell ◽  
J. K. Elliott

ABSTRACTReliable radiometrie temperature measurement has been a major challenge in making rapid thermal processing (RTP) more widely accepted. In order to meet road map requirements involving temperature uncertainty, uniformity and control, new techniques must be demonstrated and/or existing measurement methods must be substantially improved. Critical aspects of radiometrie methods for temperature measurement are centered about the topics: radiative and optical properties of the wafers including layered systems, surface roughness effects, and reflected irradiation from lamp banks and chamber walls. The systematic method for inferring temperature is rooted in the measurement equation which relates the radiometer output to the exitent spectral radiance from the target which reaches the detector and prescribes the roles that emissivity variability and stray radiation have on the result. An overview is provided on the knowledge base for optical and thermal radiative properties. Methods for reducing emissivity and stray radiation effects are summarized. Calibration procedures necessary to assure that the in-chamber or local temperature scale is traceable to the International Temperature Scale (ITS-90) are discussed. The issues which can impact improved temperature measurement practice are summarized.


1995 ◽  
Vol 389 ◽  
Author(s):  
Peter Y. Wong ◽  
Ioannis N. Miaoulis ◽  
Cynthia G. Madras

ABSTRACTTemperature measurements and processing uniformity continue to be major issues in Rapid Thermal Processing. Spatial and temporal variations in thermal radiative properties of the wafer surface are sources of non-uniformities and dynamic variations. These effects are due to changes in spectral distribution (wafer or heat source), oxidation, epitaxy, silicidation, and other microstructural transformations. Additionally, other variations are induced by the underlying (before processing) and developing (during processing) patterns on the wafer. Numerical simulations of Co silicidation that account for these factors are conducted to determine the radiative properties, heat transfer dynamics, and resultant processing uniformity.


1996 ◽  
Vol 424 ◽  
Author(s):  
R. E. I. Schropp ◽  
K. F. Feenstra ◽  
C. H. M. Van Der Werf ◽  
J. Holleman ◽  
H. Meiling

AbstractWe present the first thin film transistors (TFTs) incorporating a low hydrogen content (5 - 9 at.-%) amorphous silicon (a-Si:H) layer deposited by the Hot-Wire Chemical Vapor Deposition (HWCVD) technique. This demonstrates the possibility of utilizing this material in devices. The deposition rate by Hot-Wire CVD is an order of magnitude higher than by Plasma Enhanced CVD. The switching ratio for TFTs based on HWCVD a-Si:H is better than 5 orders of magnitude. The field-effect mobility as determined from the saturation regime of the transfer characteristics is still quite poor. The interface with the gate dielectric needs further optimization. Current crowding effects, however, could be completely eliminated by a H2 plasma treatment of the HW-deposited intrinsic layer. In contrast to the PECVD reference device, the HWCVD device appears to be almost unsensitive to bias voltage stressing. This shows that HW-deposited material might be an approach to much more stable devices.


2002 ◽  
Vol 745 ◽  
Author(s):  
Erik Haralson ◽  
Tobias Jarmar ◽  
Johan Seger ◽  
Henry H. Radamson ◽  
Shi-Li Zhang ◽  
...  

ABSTRACTThe reactions of Ni with polycrystalline Si, Si0.82Ge0.18 and Si0.818Ge0.18C0.002 films in two different configurations during rapid thermal processing were studied. For the usually studied planar configuration with 20 nm thick Ni on 130–290 nm thick Si1-x-yGexCy, NiSi1-xGex(C) forms at 450°C on either Si0.82Ge0.18 or Si0.818Ge0.18C0.002, comparable to NiSi formed on Si. However, the agglomeration of NiSi1-xGex(C) on Si0.818Ge0.18C0.002 occurs at 625°C, about 50°C higher than that of NiSi1-xGex on Si0.82Ge0.18. For thin-film lateral diffusion couples, a 200-nm thick Ni film was in contact with 80–130 nm thick Si1-x-yGexCy through 1–10 μm sized contact openings in a 170 nm thick SiO2 isolation. While the Ni3Si phase was formed for both the Si0.82Ge0.18 and Si0.818Ge0.18C0.002 samples, the presence of 0.2 at.% C caused a slightly slower lateral growth.


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