Characteristics and Impact of COPs (Pits) on Substrate Surface for ULSI Deep Submicron Process Integrity
The effect of crystal-originated particles (COPs) on ultra-thin gate oxide for recent ultra large-scale integration (ULSI) devices were studied. Various Czochralski (CZ) silicon wafers were prepared by controlling the pulling speed of silicon ingots to determine the relationships between COPs and the breakdown characteristics of the ultra thin-gate oxide. The distribution of COPs, measured by optical shallow defect analysis and the use of a particle counter, was compared with the results of timeindependent dielectric brea kdown (TZDB), timedependent dielectric breakdown (TDDB) and stressinduced leakage current (SILC) for gate oxides with thicknesses of 2.5 -5 nm. The results reveal no appreciable oxide degradation below an oxide thickness of approximately 3 nm; above this threshold value, the defect density depends strongly on the presence of crystal-originated particles. The COPs are a major factor in the degradation of ultra-thin gate oxide (less than 5 nm) in ULSI devices. The I-V measurements are readily explained by invoking Fowler-Nordheim tunneling effect. It was recently revealed that singularities (crystal-originated particles) formed on Si wafers after SCI cleaning originate from some defects in crystals and were perceived by laser particle counters. In this paper, the size distribution of crystal-originated particles is examined in detail by means of repeated SCI cleanings. It is shown that, as the crystal pulling rate becomes faster, the size distribution of crystal-originated particles shifts toward smaller size, and the total number of origins of crystal-originatedparticlesincreases. Crystal-originated particle (COP) side-wall angles and rates of change in width were measured after treatment in an SC-1 solution by atomic force microscopy (AFM) to determine the shape, size and type of the particles on a polished (100) Si wafer surface. The etched silicon tips maximum measurable slope angles were used to determine whether a COP originated from either the upper or the lower portion of an octahedral void. If the COP sidewall angle is equal to the maximum measurable slope angle of around 72°, the COP originated from the upper portion of the void.
Po-Ying Chen Shih-Chun Hung Wen-Kuan Yeh I-Fen Chen Wei-Chou Chen Kang-Ping Li Pei-Chen Yeh Hsin-Ying Huang
Department of Information Engineering,I-Shou University, No. 1, Sec. 1, Syuecheng Road., Dashu Towns Department of Information Engineering, I-Shou University, No. 1, Sec. 1, Syuecheng Road., Dashu Town Department of Electronic Engineering, National University of Kaohsiung, No. 700, Kaohsiung Universit
国际会议
上海
英文
78-83
2010-11-01（万方平台首次上网日期，不代表论文的发表时间）