COMPARISON OF EFFECTS OF PROCESS TECHNOLOGY-DERIVED INPUT PARAMETERS OF DIE-LEVEL FAILURE MODELS

Abstract

In integrated circuits, time-dependent dielectric breakdown, hot carrier injection, andelectromigration are primary die-level wear-out failure mechanisms. Failure models for these mechanisms can be used to assess and compare the parts based on their ability to withstand these failure mechanisms. The failure models require electrical input parameters: gate voltage, drain current, and current through interconnect, as well as dimensional input parameters: gate oxide thickness, gate length, and die metallization dimensions. These input parameters are unavailable in traditional documentation, such as datasheets and application notes. As a result, part users face difficulty using the failure model for part assessment. This thesis presents methodologies to obtain die-level electrical and dimensional input parameters for individual parts. The approach developed to find the input parameters uses the process technology information of a part and literature on process technology. The electrical input parameters for the time-dependent dielectric breakdown and hot carrier injection failure model are determined from transistor-level voltage-current characteristic curves provided in the literature on process technologies. The methodologies to determine the electrical input parameters are developed by utilizing transistor circuit information and the associated characteristic curves. Part manufacturers use different technologies and design rules, leading to differences in inputparameters such as die-level dimensions and electrical and environmental loads. These variations affect the ability of parts to withstand die-level failure mechanisms. Therefore, a die-level comparative assessment should be performed to compare and select the parts. Comparative assessment refers to quantifying and comparing the influence of die-level input parameters on time-to-failure of parts for individual die-level failure mechanisms using simulation-based design of experiments. Identifying the parameters that affect the part’s time-to-failure using a simulation-based design of experiments supports decision-making for derating considerations, acceptable manufacturing variations, and part selection. This thesis provides guidelines for extracting input parameters for die-level failure mechanisms and a methodology to perform comparative part assessment based on the application load condition of the system.