Single crystals for 300 mm wafer are grown by horizontal magnetic Czochralski method. 300 mm wafers are made from the vertical samples cut from crystal along ingot axial direction. Micro defects in various defect regions are investigated with various measurement methods. In order to investigate the size of the defects, the locations of defects are identified, the wafers with the defects are cut in cross-sectional direction, and the sizes of the defects are measured by transmission electron microscopy (TEM). The voids more than 20 nm size exist in vacancy-rich region. Any as-grown defect is not observed by any available measurement tools in the region having nuclei of oxidation-induced stacking fault (P-band), pure silicon in a vacancy-dominant crystal region (Pv), and pure silicon in an interstitial-silicon-dominant crystal region (Pi). High sensitive laser scattering tomography system with the detection limit of 20 nm size is used to investigate as-grown defects in P-band, Pi, and Pv regions. It is concluded that there are no as-grown defects more than 20 nm size in P-band, Pi, and Pv regions.

Gettering property of Cu and Ni was investigated after MCP thinned process wafer. The test samples were prepared to various dopant concentration types of CZ or Epitaxial wafer, and various processed thinning conditions corresponding with a total remaining thickness of 100 µm, 50 µm, and 30 µm by backside grinding. It was found that the 30 µm thinned wafer maintains its Cu gettering ability for heavily boron doped samples but Ni contamination decrease the gettering ability for all samples.

The influence of molecular weight of hydroxyethyl cellulose (HEC) on the surface qualities of a silicon wafer during final-touch polishing was investigated. Using electro-light scattering, contact-angle measurement, force-distance measurement in AFM, and X-ray photoelectron spectroscopy, confirmed that HEC is adsorbed onto the colloidal-silica-abrasive surface and the silicon-wafer surface and that the adsorption amount increases in accordance with HEC molecular weight. With the increase in HEC molecular weight in the slurry, the number of remaining particles and surface roughness on the silicon wafer are greatly reduced by a firmly adsorbed thick polymer layers on the colloidal-silica-abrasive and silicon-wafer surface that forms with the addition of 250K-molecular-weight HEC to the slurry.

A novel concept of MCP substrates that shows the enhanced internal gettering ability even in thinned state was proposed. To achieve the concept, RTA treatment in high temperature was applied to the CZ-Si substrate with a high initial oxygen concentration. It was confirmed that precipitates were formed as high density even in the near surface shallower than 100 μm, where major portion of internal gettering should take place in the MCP process. Moreover, comparable gettering ability to the EPI wafer was confirmed in our concept after thinning, especially in Ni gettering. In conclusion, it was expected that this concept is one of the possible substitutions of EPI wafers in practical MCP process.

The effects of bulk microdefects and metallic impurities on leakage currents at p–n junctions have been evaluated quantitatively by relating leakage currents with bulk defects and metallic impurities, and the results are reported. Bulk defects and metallic impurities, which were introduced by appropriate thermal treatment and intentional contamination by spin-coating metal ion solutions onto the silicon surfaces, were shown to induce heavy leakage currents at p–n junctions, which had been manufactured by boron implantation and phosphorus diffusion. We found the bulk microdefects to be critical in causing leakage currents to flow and propose that their measurements be used as a means for the determination of the bulk defect densities. Die failure rates were also used for the evaluation of the effects of metallic impurities such as Cu, Ni, and Fe on the leakage currents.