Wafer Edge Scanning With Droplet Sampling for Metal Contamination
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Solution Overview
Problem
Conventional devices for detecting metallic contaminants primarily focus on central regions of wafers, neglecting the edge regions, leading to incomplete detection and potential contamination issues.
Innovation Solution
An apparatus for edge scanning and sampling, comprising a rotating component, scanning-liquid supplying-drawing component, and supporting component, which enables thorough scanning and sampling on the edge of a sample by rotating the droplet along the edge and using a cleaning component to maintain cleanliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser beam is introduced into a measurement space to measure metal contamination, then metal contamination can be detected, but dust particles located on the way of the laser beam are also detected as metal contamination, causing measurement errors
Solution Approach 1:
The detection process is segmented into two distinct stages: first detecting all particles (dust and metal) using light scattering, then selectively identifying metal particles through eddy current detection. This segmentation allows differentiation between dust particles and actual metal contamination, eliminating false detections while maintaining comprehensive detection capability.
Solution Approach 2:
An eddy current detector is introduced as an intermediary device between the laser detection system and the final measurement result. This intermediary selectively detects metal particles by generating eddy currents in conductive materials, thereby filtering out non-conductive dust particles from the detection results and improving measurement precision.
2Measurement precision
If the entire surface of a large substrate is scanned to ensure complete contamination detection, then detection coverage is improved, but the measurement time increases significantly
Solution Approach 1:
The system performs preliminary detection using light scattering to identify all particle locations across the substrate surface before conducting eddy current detection. This preliminary action creates a map of particle positions, allowing the system to focus subsequent time-consuming eddy current measurements only on suspected metal contamination areas rather than scanning the entire surface, thereby reducing overall measurement time while maintaining detection coverage.
Solution Approach 2:
Instead of performing exhaustive eddy current detection across the entire substrate surface, the system applies partial detection by focusing eddy current measurements only on regions where particles are detected by the faster light scattering method. This partial action approach maintains adequate detection coverage for metal contamination while significantly reducing the time required compared to complete surface scanning.
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
Facilitates comprehensive sampling and detection on the edge of samples, enhancing detection accuracy and preventing cross-contamination, thereby improving the completeness and reliability of the detection process.
Implementation Method 1
When particles are located on the way of a laser beam introduced into a measurement space, light is scattered
Implementation Method 2
an eddy current detector that measures a signal generated by eddy currents
Data Source
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AI summary
An edge scanning apparatus and a metal contamination measurement device. The edge scanning apparatus comprises: a rotating component (1), which comprises a carrying portion (11), the carrying portion (11) being used for carrying a sample (A) to be tested, wherein the rotating component (1) can drive the sample (A) to be tested to rotate; a scanning liquid supplying and recycling component, which comprises a nozzle (2) used for discharging and recycling scanning liquid droplets; and a bearing component (3), which comprises a supporting arm (31), wherein the scanning liquid droplets are accommodated between the nozzle (2) and the supporting arm (31), and the scanning liquid droplets can surround an edge portion of the sample (A) to be detected. By means of the edge scanning apparatus, the edge portion of the sample (A) to be detected can be scanned and sampled, so as to provide conditions for sampling and measuring the edge portion of the sample (A) to be detected.