摘要:

The recent commercialization of Vacuum Ultraviolet spectroscopic ellipsometry (VUV SE) instruments means that it is now possible to routinely perform SE measurements at wavelengths below 190 nm. This new capability has obvious implications for lithographic work but also for the characterization of other materials of importance to the Si industry. These are materials that are nominally transparent at long wavelengths but that possess unique absorption signatures in the VUV, such as newly emerging high‐k gate materials (e.g. Al2O3, HfO2, ZrO2, Y2O3) and low k materials (porous SiO2, organo‐silicate glasses), as well as more familiar dielectrics (e.g. SiOxNy, Si3N4, SiOF, and TEOS). We provide a review of recent progress and a critical assessment of the capabilities of VUV SE with respect to a selected examples of these materials, with special emphasis on low k and high k materials. These capabilities include increased access to unique VUV spectral features as a means of tuning process parameters and increased ability to determine the thickness of thin films grown on Si. We also address the initial challenges that had to be overcome in order to develop optical constants at short wavelengths and to enable this sort of materials characterization. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622551

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Raman spectroscopy is a powerful technique for characterization of microelectronic materials and device structures. However, the commonly used visible Raman spectroscopy technique is severely limited in both lateral and depth resolution in applications to rapidly shrinking ULSI device structures. The UV micro‐Raman technique can greatly enhance the spatial resolution by taking advantage of the shorter wavelength and much smaller optical penetration depth (<10 nm in Si at 325 nm versus 400 nm in the visible). We present UV micro‐Raman mapping of stress and crystallinity in shallow trench isolated (STI) CMOS devices. The shorter optical penetration depth in Si and other wide‐gap materials also makes UV‐Raman spectroscopy very appealing in characterizing thin films of such materials. Examples will be given in characterization of ultrathin strained Si channels on SiGe buffer and thin SrTiO3and SiN dielectric films on Si. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622552

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Non‐contact, non‐intrusive photo‐thermal radiometry (PTR) was used for monitoring the ion implantation of (p‐type) industrial‐grade silicon wafers. The silicon wafers were implanted with Boron in the dose range of 1×1011‐to‐1×1016ions/cm2at different implantation energies (10 keV‐to‐180 keV). The results indicated excellent sensitivity to the implantation doses and energies. This laser‐based photothermal technique monitors harmonically photoexcited and recombining carriers and shows great potential advantages over existing methodologies for characterization of multiple semiconductor processes such as ion implantation and other device fabrication steps in the Si wafer processing industry. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622553

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

During silicon thermal chemical vapor deposition, reactions occurring in the gas phase above the wafer surface can strongly influence the deposited film quality. Depending on process conditions (e.g., temperature, silicon precursor, carrier gas, pressure) gas phase reactions can include not only precursor decomposition but also nucleation of silicon nano‐particles above the wafer surface. Optical diagnostics were employed to investigate such processes during silicon chemical vapor deposition via silane pyrolysis. Measurements were performed in a vertical flow, rotating disk reactor under various process conditions. Gas phase silicon particle spatial distributions were determined with elastic light scattering. Chemical composition of the particles was investigatedin situwith vibrational Raman spectroscopy. Raman spectra showed that the particles were composed of amorphous silicon and/or crystalline silicon, depending on growth temperature. Raman spectral features of the crystalline silicon also indicated crystalline domain sizes in the ca. 3 nm to ca. 10 nm size range. Gas phase temperature measurements (in the absence of particles) were used to estimate an amorphous‐to‐crystalline silicon transition temperature of ca. 866 K. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622554

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A novel spectral imaging ellipsometer based on a mono‐axial power spectrograph has been developed for one‐dimensional spectroscopic measurement of patterned structures. To obtain the imaging data of a patterned sample using ellipsometry can be realized by conventional ellipsometers with 2‐dimesional (2D) scanning sample stage or 2D imaging ellipsometers with imaging optics. The former has major advantage of high precision, but it has disadvantage in the measurement speed due to mechanical scanning. The latter uses a 2D imaging detector to extract 3D spatial information. So it must be the type of a single‐wavelength ellipsometer. Analyzing the spatial structure of a multi‐layered sample needs the spectroscopic measurement at each spatial point. Therefore we have developed a real‐time spectral imaging ellipsometer base on a mono‐axial spectrograph which can give not only 1D spatial information but also 1D spectroscopic information. The mono‐axial spectrograph is simply composed of entrance slit, holographic transmission grating, and cylindrical doublet as shown in Figure. The custom‐built spectral imaging ellipsometer has the spectral resolution of 10 nm and the spatial resolution of 200 &mgr;m. In the near future the spatial resolution will be enhanced by adopting a focusing optics. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622555

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The Carrier Illumination™ (CI) method is an optical technique for non‐destructive in‐line monitoring of post‐anneal junction depth, pre‐anneal pre‐amorphisation implant (PAI) depth, and dose. This work describes the sensitivity of the CI‐signal to the as‐implant dose and demonstrates that a universal response function can be derived for doses below the amorphisation limit. For the implants where the elements/doses cause amorphisation, the CI‐signal reflects directly the thickness of the amorphous depth. In the case of annealed structures, it is shown that CI provides important information on the electrical activation of the dopant. This is illustrated by the analysis of CVD‐layers subsequently annealed and of junction profiles produced by laser annealing. In both cases nearly identical dopant profiles are observed with secondary ion mass spectrometry while the electrical activation as derived from sheet resistance measurements is very different. This very different activation level is clearly reflected in the CI‐signal. This indicates that the CI‐signal is not solely related to the junction depth and the profile abruptness but also to the electrical activation of the dopants. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622556

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A unique analytical methodology has recently been developed to perform real‐time, on‐line chemical analysis of bath solutions in semiconductor fabrication tools. A novel, patented fiber optic sensor is used to transmit infrared light directly through the tube walls of the circulating bath solutions within the fabrication tool in a completely non‐invasive, non‐extractive way. The sensor simply “clips” onto the tubing, thus permitting immediate analysis of the bath composition by Fourier Transform infrared (FTIR) spectroscopy. The infrared spectrometer is capable of multiplexing up to eight “Clippir™” sensor heads to a single interferometer using fiber optic cables. The instrument can analyze almost any bath solution utilized today. The analysis is performed using the near‐infrared (NIR) portion of the electromagnetic spectrum, where absorption bands related to molecular vibrations can be found. The Fourier Transform infrared spectrometer gives access to absorption bands over a wide range of frequencies (or wavelengths), and the absorptions are correlated to concentrations using a chemometric approach employing a partial least‐squares algorithm. Models are generated from this approach for each chemistry to be analyzed. This paper will review the analytical technology necessary to make such measurements, and discuss the instrument performance criteria required to achieve accurate and precise measurements of bath chemistries. The ability to measure non‐infrared absorbing compounds will be discussed, as will the nature of the influence of sample temperature on measurement. Issues critical to the development of robust models and their direct implementation on multiple channels and even different instruments will be considered. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622557

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Experimental measurements and simulations are used to provide an overview of key issues with the electrical characterization of metal‐oxide‐semiconductor (MOS) devices with ultra‐thin oxide and alternate gate dielectrics. Experimental issues associated with the most common electrical characterization method, capacitance‐voltage (C‐V), are first described. Issues associated with equivalent oxide thickness extraction and comparison, interface state measurement, extrinsic defects, and defect generation are then overviewed. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622558

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Non‐contact electrical metrology includes a variety of characterization techniques used to determine a number of material/device electrical parameters. These powerful methods, used on full wafers at various processing stages, complement the traditional device‐based contact electrical (capacitance‐voltage and current‐voltage) measurements of MOS‐based structures. The non‐contact electrical techniques are usually built around measurements of surface photovoltage and surface voltage in combination with illumination and corona charge deposited on a sample. In principle this allows recombination lifetime, minority carrier diffusion length, and iron contamination density to be determined for bulk silicon; generation lifetime, doping density and doping profile to be measured for near‐surface silicon; and equivalent oxide thickness, oxide charge density, mobile charge density, total charge density, flat band voltage, dielectric integrity and other parameters to be obtained for dielectric films. Interface trap density can be used for qualification of the interface between silicon and dielectric. The non‐contact nature of these measurement techniques is particularly attractive because it makes most of them non‐destructive, non‐invasive and allows for diagnostics in the wafer processing stages, rather than waiting for final device characterization. Some methods offer high‐resolution full‐wafer mapping capabilities. A few of them are destructive by design such as the soft‐breakdown field measurements. Most of the non‐contact electrical measurements offer excellent process step isolation, and opportunity for integrated metrology. They are less expensive, do not require fabrication of the test structures, and require significantly less preparation and measurement time compared to the traditional MOS‐device based analogues. This early and short loop measurement capability is the most important feature. In some circumstances the fast turn‐around of the product characterization has so high priority that it makes a lower accuracy and/or frequent calibrations, necessary for some non‐contact electrical techniques, tolerable (however, if there is no final correlation to device performance they are useless!). In this paper we review the non‐contact electrical measurement techniques most often used in the semiconductor industry for characterization of bulk silicon, near‐surface silicon, dielectrics and interface between silicon and dielectric films. We provide a comparison of the experimental data with the theory derived from widely accepted publications [1–5], and discuss the potential sources of discrepancies between the theory of some non‐contact measurements and their implementation in commercial products. These potential discrepancies could cause systematic inaccuracy in measurements and disagreement between metrology using equipment fabricated by different vendors, resulting in considerable standardization challenges for the semiconductor industry. We highlight concerns when applying ASTM standards developed for non‐contact electrical measurements [6 – 8] to current characterization of new semiconductor and dielectric materials. The goal of this paper is to demonstrate advantages and also the challenges in the non‐contact electrical measurements, to define the problem areas and to provide recommendations for possible improvements and directions to overcome existing problems. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622559

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Highly sensitive, accurate and precise methods for measuring the properties of dielectrics used in sub 0.13 &mgr;m technology are required. It is particularly critical to monitor the electrical properties of the gate dielectric. The electrical properties of thin dielectrics are assessed with a new, non‐contaminating, non‐damaging elastic probe. This probe forms a small diameter (∼30 &mgr;m to 50 &mgr;m ) Elastic Metal gate (EM‐gate) on the surface of a dielectric. Subsequent electrical measurements are made with advanced Capacitance‐Voltage (CV), Conductance‐Voltage (GV), and Current‐Voltage (IV) techniques. Valuable and essential information about the dielectric thickness and quality, leakage current, Si‐SiO2interface quality, and channel carrier density profile is obtained. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622560

出版商:AIP    

年代:1903

数据来源: AIP