Accelerating 32nm BEOL technology development by advanced wafer inspection methodology

Abstract

In the early development stage of 32nm processes, identifying and isolating systematic defects is critical to understanding the issues related to design and process interactions. Conventional inspection methodologies using random review sampling on large defect populations do not provide the information required to take accurate and quick corrective action. This paper demonstrates the successful identification and isolation of systematic defects using a novel methodology that combines Design Based Binning (DBB) and inline Defect Organizer (iDO). This new method of integrating design and defect data produced actionable inspection data, resulting in fewer mask revisions and reduced device development time. INTRODUCTIONEngineers must balance design margins and process windows, while achieving fast development times. In the early development stage, identifying systematic defects accurately and quickly is critical in order to minimize cost and shorten the development cycle. Bright field inspectors are often used to help identify integration defects, but high sensitivity inspections can produce very large defect populations that contain both random and systematic defect types. Limited review sampling on these high defect counts prevents the effective separation of design or processrelated defects from non-relevant defect types. Thus, these conventional inspection methods produce an incomplete picture of issues related to process and design interactions, making it difficult, if not impossible, for engineers to take effective corrective action. DBB is a new technology that classifies defects into groups based on design background [1,2]. In addition, defect critical index (DCI) can be extracted to describe what the impact of defect is [3], while iDO uses design and defect attributes to identify and separate different classes of defects. Using these technologies, systematic defects can be identified and separated from the overall defect population, resulting in improved yield relevance and faster solution of production integration issues. For example, the defect population can be

Systematic defect management by design aware inspection

“…Once all critical defects are detected, binning and prioritization enable users to identify key defect types while optimizing the use of SEM review capacity. This type of approach has been demonstrated in earlier work [3]. To implement such comprehensive design-aware defect management, two major components are required: 1) Use of design layout data (e.g.…”