Fast, exact and non-destructive diagnoses of contact failures in nano-scale semiconductor device using conductive AFM

Abstract

We fabricated a novel in-line conductive atomic force microscopy (C-AFM), which can analyze the resistive failures and examine process variance with an exact-positioning capability across the whole wafer scale in in-line DRAM fabrication process. Using this in-line C-AFM, we introduced a new, non-destructive diagnosis for resistive failure in mobile DRAM structures. Specially, we focused on the self-aligned contact (SAC) process, because the failure of the SAC process is one of the dominant factors that induces the degradation of yield performance, and is a physically invisible defect. We successfully suggested the accurate pass mark for resistive-failure screening in the fabrication of SAC structures and established that the cause of SAC failures is the bottom silicon oxide layer. Through the accurate pass mark for the SAC process configured by the in-line C-AFM analyses, we secured a good potential method for preventing the yield loss caused by failures in DRAM fabrication.

Advanced measurement and diagnosis of the effect on the underlayer roughness for industrial standard metrology

“…Other examples include: scanning of the channel holes of flash memory devices and the surfaces of solder or copper pillar bump materials, measurements of the critical dimensions of the mask after development inspection (ADI) processes, and inspections to determine electrical failures in self-aligned contact (SAC) or landing pad (LP) processes in DRAM modules. In addition, roughness examinations of the ultrathin films without any interference from the lower membrane have been implemented 12,14 .…”

A Microstructural Analysis of 2D Halide Perovskites: Stability and Functionality

“…By accurate adjustment of the tip work function on the reference sample, the other materials' surface work function can be determined (Shao et al, 2016). In high-resolution C-AFM (Yang et al, 2009;Shin et al, 2013), the current-voltage characteristics of the sample surface could be easily captured by the mapping of the topography. A large current flow points toward high conductivity of the sample and a strategic character of the charge transport (Bristowe et al, 2015;Wang et al, 2016;Si et al, 2017;Lee et al, 2018;Xu et al, 2018;Eichhorn et al, 2018).…”

Current-Limited Conductive Atomic Force Microscopy

“…With continuously shrinking electronic device dimensions, − precise knowledge about the electrical behavior of different materials at the nanoscale is indispensable. Conductive atomic force microscopy (CAFM) was originally invented in 1993 and nowadays has become the standard technique used by the semiconductors industry to evaluate the electronic properties of materials and devices at the nanoscale. − In brief, CAFM is a modification of standard AFM that relies on three components: a conductive and sharp nanoprobe (often referred to as tip), a voltage source to apply a potential difference between the nanoprobe and the sample, and a current preamplifier that converts analog currents (picoamperes) into digital signals readable by standard integrated circuits (volts) . Early studies in this field were focused on analyzing the reliability of thin dielectric films, − although today the use of CAFM has widespread to many other fields, , such as ferroelectricity, lithography and nanopatterning, , and biology …”