Atomic force microscopy: a powerful tool for surface defect and morphology inspection in semiconductor industry

The industrial use of instruments based on Atomic Force Microscopy that started in the mid 1990's has seen a wide spectrum of applications for product and process controls in semiconductor industry where the continuous effort of smaller and smaller size defect reduction is a driving force of the technological development. The paper will examine a subsection of this world, the electronic grade silicon wafer manufacturing and product development. In this area, the technique is applied to the measurement of surface defect geometry down to a size of a few angstroms and a surface micro-roughness at various areas of inspection from 1E-10 cm2 to 1E-4 cm2. First, a brief description of the measurement principle is given in order to discuss aspects related to accuracy and stability of the technique when micro-roughness values are considered. Then, a few examples involving the inspection of crystal related defects detectable on the silicon wafer surface as well as different textures following various surface-finishing processes will be discussed. Finally, examples of the use of Atomic Force Microscopy on Silicon On Insulator and strained silicon materials will give an insight about the relevance of this technique in the field of New Materials development in the electronics industry

The impact of organic contamination on the oxide-silicon interface

This paper collects the results of a study aimed to investigate the impact of organic contamination on the electrical properties of the silicon oxide and of the silicon oxide-silicon interface. Some wafers were contaminated by immersion in solution of diethylphthalate (DEP) in solvent. The wafers were then oxidized to perform surface recombination velocity measurements by Elymat, and capacitors were fabricated for capacitance vs. voltage and capacitance vs time measurements. In addition, the interface state density was measured by the MOS-DLTS technique and the gate oxide integrity was evaluated by constant current stress. Elymat measurements of surface recombination velocity show that surface recombination velocity is increased by organic contamination. From the point-of-view of the intrinsic properties of the silicon oxide-silicon interface, MOS-DLTS showed the most significant effects. These measurements allowed identifying a band of interface states located around E v+0.1eV as related to organic contamination. However, the most relevant effects of organic contamination were observed by electrical stress of the oxide. Indeed, the fraction of capacitors with degraded breakdown voltage increased dramatically in contaminated wafers

Reliable quantification of inorganic contamination by TXRF

The European Integrated Activity of Excellence and Networking for nanoand Micro-Electronics Analysis (ANNA), www.ANNA-i3.net, has addressed the further development and assessment of methodologies for the detection of low concentration inorganic contaminants on and in silicon as well as for novel materials. The comparison of various analytical techniques available to the ANNA partners helped to identify the degree of comparableness of results revealed at different installations. The assessment of improved methodologies as well as the reliability of quantification and calibration procedures of specific analytical techniques such as Total-Reflection X-ray Fluorescence (TXRF) analysis has been of particular interest

Defect structure and strain reduction of 3C-SiC/Si layers obtained with the use of buffer layer and methyltrichlorosilane addition

3C-SiC layers were deposited on Si substrates by using a low temperature buffer layer and the addition of methyl trichloro silane (MTS) to the gas phase during the high temperature thick film growth. Several samples were grown by varying the deposition temperature and the MTS content in order to study how these parameters affect the layer quality and the lattice defects. All of the grown layers are single crystalline and epitaxial to the substrate. The formation of empty voids at the SiC/Si interface was successfully avoided. The surface of the layers grown with MTS addition was smoother and contained less residual strain. A 15 ?m thick 3C-SiC sample was grown with an optimized process in order to evaluate its residual strain and bow

Highly Sensitive Detection of Inorganic Contamination

As the detection of inorganic contaminants is of steadily increasing importance for the improvement of yields in microelectronic applications, the aim of one of the joint research activity within the European Integrated Activity of Excellence and Networking for Nano- and Micro-Electronics Analysis (ANNA, site: www.ANNA-i3.org) is the development and assessment of new methodologies and metrologies for the detection of low concentration inorganic contaminants in silicon and in novel materials. A main objective consist in the benchmarking of various analytical techniques available in the laboratories of the participating ANNA partners, including the improvement of the respective detection limits as well as the quantitation reliablity of selected analytical techniques such as total-reflection x-ray fluorescence (TXRF) analysi