Wafer Crack Detection via Multi-Axis Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor manufacturing, the increasing number of interconnection layers leads to surface irregularities, which complicates film coating and photolithographic processes, and undetected wafer cracks during polishing can result in breakage and contamination, causing downtime and increased costs due to damage to cleaning equipment.
Innovation Solution
A substrate processing apparatus equipped with a substrate abnormality detection unit that uses an imaging device and output monitoring system to detect cracks or chipping by comparing signal thresholds, preventing broken wafers from being transported to the cleaning unit and reducing downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical sensor is used to detect wafer presence, then the wafer presence can be detected, but wafer cracks cannot be detected unless the optical axis passes through the cracked portion
Solution Approach 1:
The patent transitions from a single optical axis detection method to a multi-axis imaging system. By arranging multiple imaging devices at different positions and angles around the wafer, the system achieves comprehensive crack detection without requiring the optical axis to precisely align with crack locations, thereby resolving the limitation of traditional optical sensors.
Solution Approach 2:
The detection system is divided into multiple independent imaging devices positioned at different locations. Each imaging device captures a specific portion or angle of the wafer, and the combined data from all segments provides complete crack detection coverage, overcoming the single-point detection limitation.
2Productivity
If wafer cleaning is performed without detecting cracks, then the cleaning process can be completed, but the wafer may break into pieces causing damage to cleaning members and increasing downtime
Solution Approach 1:
The imaging detection is performed before the wafer enters the cleaning unit, allowing cracks to be identified in advance. This preliminary detection enables the system to prevent damaged wafers from undergoing cleaning, thereby avoiding wafer breakage and subsequent damage to cleaning members while maintaining overall productivity.
Solution Approach 2:
By detecting cracks before cleaning, the system takes preventive action to stop the processing of damaged wafers. This preliminary anti-action counteracts the potential harmful effect of cleaning cracked wafers, which would otherwise lead to wafer fragmentation and equipment damage.
3Reliability
If the substrate abnormality detection unit is added between polishing and cleaning, then wafer cracks can be detected, but the device complexity increases
Solution Approach 1:
The imaging devices are positioned to serve multiple functions: they detect wafer presence, identify crack locations, and assess wafer orientation. This multi-functionality reduces the need for separate specialized sensors, thereby limiting the increase in device complexity while achieving comprehensive defect detection.
Solution Approach 2:
The detection function is merged into the existing transport mechanism by utilizing the space and structure already present in the polishing-cleaning workflow. The imaging devices are integrated into the wafer transfer path, combining detection capabilities with the existing apparatus structure rather than adding completely separate systems.
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
Prevents wafer breakage during cleaning, reduces damage to equipment, and minimizes restoration time by detecting substrate abnormalities before they cause further damage, thus maintaining operational efficiency and reducing costs.
Implementation Method 1
an imaging device configured to image the substrate
Data Source
AI summary
A substrate processing apparatus having a detecting unit that can detect an abnormality of a substrate such as a crack of the substrate or chipping of the substrate is disclosed. The substrate processing apparatus includes a polishing unit configured to polish a substrate, a cleaning unit configured to clean the polished substrate, a substrate abnormality detection unit configured to detect an abnormality of the substrate, and a substrate transporting mechanism configured to transport the substrate in the order of the polishing unit, the substrate abnormality detection unit, and the cleaning unit. The substrate abnormality detection unit includes an imaging device configured to image the substrate, and an output monitoring unit configured to determine a status of the substrate by comparing a signal obtained from the imaging device with a predetermined threshold.