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We have investigated the carbon and fluoride contaminants on silicon wafers during their storage in quartz-glass boxes equipped with carrier cases made of either polypropylene (PP), polybutylene-terephthalate (PBT), or perfluoroalkoxy polymer (PFA). The adsorbed organic contaminants on the wafer surfaces were identified by time-of-flight secondary-ion mass spectrometry (TOF-SIMS). The concentrations of contaminants on the wafer surface have been measured as a function of wafer storage positions as well as carrier case storage time. For quantitative analyses, secondary-ion mass spectrometry (SIMS) combined with the encapsulation method was employed, and carbon ( 12 C − ) and fluorine ( 19 F − ) ions were detected. It has been found that the amount of adsorbed contaminants on the surface of silicon wafers depend on both the wafer storage conditions and the carrier case materials.

Raman spectroscopy is a powerful technique for revealing spatial heterogeneity in solid-state structures but heretofore has not been able to measure spectra from multiple positions on a sample within a short time. Here, we report a novel Raman spectroscopy approach to study the spatial heterogeneity in thermally annealed amorphous silicon (a-Si) thin films. Raman spectroscopy employs both a galvano-mirror and a two-dimensional charge-coupled device detector system, which can measure spectra at 200 nm intervals at every position along a sample in a short time. We analyzed thermally annealed a-Si thin films with different film thicknesses. The experimental results suggest a correlation between the distribution of the average nanocrystal size over different spatial regions and the thickness of the thermally annealed a-Si thin film. The ability to evaluate the average size of the Si nanocrystals through rapid data acquisition is expected to lead to research into new applications of nanocrystals.

Secondary ion mass spectrometry (SIMS) has been a central analytical technique for the microelectronics industry. More precise analysis has become important along with the development and process monitoring of integrated circuits (ICs) production. The level of quantitative analysis is influenced by random and systematic uncertainties. The origin of these uncertainties in SIMS have been well documented by Werner. 1 A number of authors have reported measurement techniques to minimize the contribution of uncertainties to the analytical results. [2][3][4][5][6][7][8][9][10] One of the error factors is related to the specimen holder, itself. It has been reported that the obtained secondary ion intensities are different from those among the windows of the specimen holder, 8,11 or from the tilted holder to the electric field of the extraction space. 6,8 Also, the ion intensities fall off as the analysis location approaches the edge of the holder window. 6,13,14 These detrimental phenomena are attributed to the deviation of secondary ion trajectories by a distortion of the electric field, which is commonly applied above the sample surface in order to effectively collect the emitted secondary ions. It has been accepted that the distortion is caused by warping of the holder faceplate due to pressure from the mounting springs. 9 Besides, it has been demonstrated by a computer simulation that a non-uniform electric field exists near to the window edge of the holder. 14 In the Cameca IMS-type SIMS instrument, a high extraction field, typically 1.0 kV/mm, is used between the sample and a grounded extraction plate (immersion lens cover); therefore, the effect of the specimen holder is more sensitive than for other types of instruments. There are no investigations mentioned in the literature concerning a distorted electric field above various types of specimen holders.In this work, we investigated the distortion area of the electric field near to the edge of the specimen holder window as a function of the faceplate thickness of the specimen holder by a computer simulation after confirming that the computed results was in good agreement with the SIMS experimental results. We also demonstrated the advantage of a specimen holder with a tapered-edge faceplate. ExperimentalThe experiments were conducted using a Cameca IMS-4f ion microscope. A Cs + primary ion beam with an impact energy of 14.5 keV was used. The primary ion current was 100 nA and the raster size was 250 × 250 µm 2 . In the IMS-4f, the specimen holder was biased to -4.5 kV for the detection of negative secondary ions. The distance between the surface of the specimen holder and the grounded extraction plate (immersion lens cover) was 4.5 mm. Thus, an electric field of 1.0 kV/mm was applied above the surface of the specimen holder. 28 Sisecondary ions were detected using a Faraday-cup detector. The diameter of the analyzed area in the center of the crater bottom was 60 µm. The types of specimen holders used in this experiment are summarized in Table 1. The type-B holde...

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