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Yoo W.S.,WaferMasters Inc. | Kim J.H.,Korea Advanced Institute of Science and Technology | Kim J.H.,SK hynix | Han S.M.,Korea Advanced Institute of Science and Technology
Journal of Micro/Nanolithography, MEMS, and MOEMS | Year: 2014

Characterization of silicon stress near copper (Cu)-filled through-silicon via(s) (TSVs) was demonstrated using high-resolution micro-Raman spectroscopy. For depth profiling of Si stress distribution near TSVs, a polychromator-based, multiwavelength excitation Raman measurement with different probing depths was used. The design concept of the polychromator-based, multiwavelength micro-Raman spectroscopy system, including the importance of the high-spectral resolution and multiwavelength excitation capability in three-dimensional (3-D) Si stress characterization, was described. Silicon stress near Cu-filled TSVs, with various sizes and layouts, was measured and analyzed before and after Cu annealing steps. Main factors impacting Si stress near Cu-filled TSVs are analyzed based on Raman characterization results on various types of TSV structures, layouts and Cu annealing conditions. Large variations in Si stress in TSV arrays were measured in wafers with poor Cu fill characteristics and in wafers annealed in nonoptimized conditions. The Cu annealing sequence and annealing conditions are found to be significantly important for managing Si stress and the reliability of Cu-filled TSVs. Substantially lower Si stress was measured near Cu-filled TSVs with voids. Multiwavelength micro-Raman spectroscopy can be used as a very effective noncontact, nondestructive, inline TSV process and Si stress monitoring technique. © The Authors. Source

Jian S.-K.J.,Taiwan Semiconductor Manufacturing Company | Jeng C.-C.,Taiwan Semiconductor Manufacturing Company | Wang T.-C.,Taiwan Semiconductor Manufacturing Company | Huang C.-M.,Taiwan Semiconductor Manufacturing Company | And 2 more authors.
ECS Journal of Solid State Science and Technology | Year: 2013

Room temperature photoluminescence (RTPL) and Raman spectroscopy were used for characterizing plasma-induced-damage (PID) of Si during plasma assisted Si processing. Oxide films with thicknesses of ~200 and ~600 nm were grown on 300 mm wafers by plasma enhanced chemical deposition (PECVD). Bare Si wafers with native oxide and PECVD oxide films were plasma etched under different etching and bias radio frequency (RF) power conditions. Oxide etch rate, oxide uniformity and RTPL spectra/intensity were measured and characterized under three excitation wavelengths (532, 650 and 827 nm) with different probing depths. High spectral resolution Raman measurements were performed under various excitation wavelengths from the ultraviolet (UV) to visible (VIS) region to verify the distribution of plasma etching damage in the depth direction as a function of plasma etching condition and structure of specimens. A distinct pattern of PID, corresponding to showerhead patterns, common to a typical plasma etching system, was observed from RTPL wafer mapping results. Multiwavelength Raman characterization revealed that the physical damage to the Si crystalline lattice, from plasma etching, was concentrated at, or near, the Si surface and SiO2/Si interface. Identification and characterization of PID were successfully done by using multiwavelength RTPL and Raman spectroscopy. © 2013 The Electrochemical Society. Source

Yoo W.S.,WaferMasters Inc. | Kang K.,WaferMasters Inc. | Murai G.,Kyoto Institute of Technology | Yoshimoto M.,Kyoto Institute of Technology
ECS Journal of Solid State Science and Technology | Year: 2015

Photoluminescence (PL) spectra from lightly boron (B) doped p--Si(100) under 488.0 nm Ar+ ion laser excitation over the temperature range of 22 Κ-290 K is presented. Change of PL peak height (maximum intensity), peak position, peak area (areal intensity), full-width-at-half-maximum (FWHM: peak width) were determined as a function of temperature. PL intensity was sharply decreased with temperature increase in the temperature range of 22 Κ - 170 Κ and then slowly increased again in the temperature range of 170 Κ-290 Κ. Phonon replicas of a relatively sharp band-to-band (or band edge (BE)) PL peak were clearly measured at low temperatures (≤90 Κ). PL spectra became broader and the phonon replicas were barely distinguishable as the temperature was increased. The envelope of the main PL peak and the broadening of peak width with the Si temperature were qualitatively in good agreement with the Maxell-Boltzmann probability distribution function. The direction of peak position shift with Si temperature change was also in good agreement with the temperature dependence of the Si bandgap. All measured PL spectra were curve fitted using combinations of modified Gaussian function(s) and standard Gaussian function(s). A simplified curve fitting method for broad PL spectra, consisting of the BE peak and band tail peak, using an exponentially modified Gaussian (EMG or ExGaussian) function and a number of standard Gaussian functions, was proposed from a practical usage point of view. Radiative recombination processes in Si and potential industrial applications of the PL characterization technique were discussed. © The Author(s) 2015. Published by ECS. Source

Yoo W.S.,WaferMasters Inc. | Kang K.,WaferMasters Inc.
ECS Journal of Solid State Science and Technology | Year: 2016

A surface heat-treatment method for semiconductor wafers using a xenon arc lamp is described. High absorption coefficients of silicon wafers in ultra violet (UV) region and short process time made selective surface heating possible. The surface melting of entire 150 mm diameter Si wafers was demonstrated in less than 2 s at a lamp power of 15 kW. By focusing UV light into a limited area on Si wafer surface, surface melting of a selectively exposed area was demonstrated at a much lower lamp power. The surface temperature ramp rate is estimated to be on the order of 1000°C/s. Si wafers, with various implanted species (P+, As+, B+ and BF2 +) and energies (1 keV-70 keV), were annealed for implant damage recovery and electrical activation using the Xe lamp under different scanning speeds. Sheet resistance and secondary ion mass spectroscopy (SIMS) depth profiling measurement results from the scanning rapid thermal annealing (RTA) successfully demonstrated the feasibility of the technique in semiconductor RTA processing applications. Electrical activation with desired levels of dopant diffusion can be achieved by optimizing process variables such as lamp power, distance between the lamp and Si wafer, area of light exposure and scanning speed. © The Author(s) 2015. All rights reserved. Source

Yoo W.S.,WaferMasters Inc. | Ueda T.,WaferMasters Inc. | Ishigaki T.,WaferMasters Inc. | Kang K.,WaferMasters Inc.
ECS Transactions | Year: 2010

A multi-wavelength, micro Raman spectroscopy system was designed and used for non-contact and non-destructive thickness and Ge content characterization of Si1-xGex/Si. The thickness and Ge content estimated by Raman measurements were compared to those values obtained from X-ray diffraction (XRD) and X-ray reflectance (XRR) measurements for cross-reference and showed very good agreement. The multi-wavelength excitation capability of the Raman system allows non-contact and non-destructive probing of Ge concentration as well as Si stress in Si1-xGex/Si along the depth direction. The Ge concentration gradient of small size test pads (as small as 10μm x 10μm) in depth direction were successfully measured using the multi-wavelength Raman system. The multi-wavelength Raman system with high spectral and spatial resolution is found to be very attractive and powerful for characterizing advanced semiconductor materials, such as Si1-xGex/Si and strained Si. It is also very useful for monitoring and controlling process equipment and process conditions. ©The Electrochemical Society. Source

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