Lithography Tool Topography Measurement for Wafer Defect Detection
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Solution Overview
Problem
In semiconductor fabrication, detecting microscopic defects in a timely manner is crucial due to shrinking device dimensions, but existing monitoring and inspection methods increase manufacturing costs and delays, and undetected defects can lead to scrapped wafers and reduced yield.
Innovation Solution
A system and method utilizing a lithography exposure tool with a measurement unit that obtains topography data through optical illumination and a processor to generate statistical data, producing a defect notification if the data is outside a control limit, enabling early detection of defects such as dispensing errors in photoresist layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extensive monitoring and inspection methods are used to detect defects, then defect detection capability is improved, but manufacturing time and cost increase
Solution Approach 1:
The system performs preliminary defect detection by measuring topography parameters (such as surface height, roughness, or curvature) immediately after photoresist dispensing but before the wafer enters the lithography exposure tool. This preliminary measurement allows defects to be identified early in the process, preventing wasted lithography exposure on defective wafers and reducing overall manufacturing time while maintaining high defect detection capability
2Reliability
If traditional inspection methods are used, then defect detection is achieved, but process delays increase
Solution Approach 1:
The system combines the lithography exposure tool with an integrated topography measurement capability, allowing defect detection to be performed within the existing lithography tool rather than requiring separate inspection equipment. This merging of functions enables simultaneous or sequential measurement and exposure operations, improving process efficiency while maintaining reliable defect detection
Solution Approach 2:
The lithography exposure tool is equipped with multi-functionality, serving both as a lithography processing device and as a defect detection device through its integrated topography measurement system. This universal device performs multiple functions (lithography exposure and defect inspection) without requiring separate specialized equipment, thereby improving productivity while maintaining detection reliability
3Loss of substance
If defects are not detected early, then manufacturing cost increases due to scrapped wafers, but early detection requires additional measurement equipment
Solution Approach 1:
The system uses the existing lithography exposure tool for dual purposes: both lithography processing and defect detection through integrated topography measurement. This approach reduces wafer scrap rate by enabling early defect detection without adding separate measurement equipment, thereby reducing system complexity while minimizing material loss
Solution Approach 2:
The lithography exposure tool performs self-diagnosis and defect detection on wafers before processing, using its own integrated measurement capabilities. This self-service approach allows the tool to identify defective wafers and prevent their processing, reducing wafer scrap rates without requiring external inspection equipment and maintaining acceptable system complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for timely detection of defects, reducing manufacturing delays and costs by identifying issues before additional wafers are processed, thereby improving yield and process efficiency.
Implementation Method 1
obtain topography data of the specimen by illumination of a surface of the specimen with an optical signal
Data Source
AI summary
The present disclosure generally relates to a system and a method for detecting a defect in a specimen. More particularly, the present disclosure relates to a lithography exposure system and a method for detecting a dispensing error in a wafer The present disclosure provides a system for detecting a defect in a specimen having a lithography exposure tool including a measurement unit and a stage, the measurement unit is configured to obtain topography data of the specimen placed on the stage by illumination of a surface of the specimen with an optical signal, and a processor configured to generate a statistical data from the topography data and produce a defect notification if the statistical data is outside of a control limit.