Inspection / metrology evaluation of fine pitch test vehicles for advanced packages

Abstract

The demand for integrated silicon packages is driving packaging advancements for increasingly fine circuit pattern designs. Due to the thinner copper and finer features required for advanced packaging, copper line defects can significantly impact yield and reliability. Industry Automated Optical Inspection (AOI) capabilities for packaging features are reaching detection limits.Phase One of the iNEMI metrology project surveyed industry capability and completed a gap analysis. This work established the basis for the current activities in Phase Two. A fine featured test vehicle was designed and fabricated using thin film processing technologies on both glass and silicon substrates to evaluate and assess the limits of today's AOI metrology equipment. The test vehicle also provided a platform to develop future metrology capability required to close the technical gaps with respect to product requirements and process and material capabilities.The test vehicle samples were provided to various industrial AOI equipment suppliers to evaluate their capabilities in evaluating fine lines and spaces. The integrity of the fine wiring lines and spaces was compared between a control pattern and known defects utilizing wiring patterns from 10 μm lines and spaces to 1 μm lines and spaces. Various types of features including different orientations were evaluated: A) Line width violations; b) Spacing violations; c) Excess copper or missing copper; d) Shorts; e) Opens. This paper will review the details of the Phase Two test vehicle and the results from the AOI evaluations, and present a roadmap for the next phase of the study with test vehicles on organic substrates.