Wafer Inspection Using Shaped Wavefronts for Bulge Defect Detection
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Solution Overview
Problem
The challenge in semiconductor manufacturing is the formation of voids or bulge defects during wafer-to-wafer bonding, which affect electrical connections and surface integrity, requiring high-throughput detection methods.
Innovation Solution
An inspection method using coherent light with a shaped wavefront to detect bulge defects by capturing and analyzing reflection beam images, employing a probe beam generation device, imaging apparatus, and data processing system to identify and classify defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional inspection methods are used to detect bulge defects, then detection capability is provided, but throughput is insufficient for high-volume manufacturing
Solution Approach 1:
The inspection system segments the wafer inspection into multiple parallel detection channels, each handling a specific region or type of defect detection. This allows simultaneous processing of multiple areas, increasing throughput while maintaining detection precision through dedicated optimization of each segment.
Solution Approach 2:
The system transitions from conventional two-dimensional optical inspection to three-dimensional surface profiling by measuring height variations. This dimensional addition enables detection of bulge defects that are invisible in planar views, improving detection capability while the parallel processing of multiple height points maintains high throughput.
2Measurement precision
If high-resolution imaging is used to detect small bulge defects, then measurement precision is improved, but inspection time increases reducing throughput
Solution Approach 1:
The system replaces conventional mechanical scanning or sequential optical focusing with a non-contact optical field-based measurement approach. Multiple measurement points are captured simultaneously using optical interference or focusing techniques, achieving high-resolution height mapping without the time penalty of mechanical scanning or sequential imaging.
Solution Approach 2:
The system performs preliminary focusing and alignment operations before the actual measurement, and uses reference surfaces to pre-calibrate the measurement field. This preliminary preparation enables rapid subsequent measurements without repeated adjustment, reducing inspection time while maintaining precision through pre-optimized optical paths.
3Measurement precision
If multiple inspection parameters are measured to classify defects, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The inspection system uses a single optical measurement platform that can extract multiple defect parameters (height, area, shape, position) from the same set of measurements. This multi-functional approach eliminates the need for separate inspection devices for different parameters, reducing overall system complexity while improving defect classification accuracy through comprehensive parameter sets.
Solution Approach 2:
The system combines multiple measurement functions and data processing operations into a unified inspection workflow. Height measurements, area calculations, and defect classification are performed in an integrated manner using shared hardware and software resources, reducing complexity through consolidation while maintaining comprehensive defect analysis capabilities.
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
High-throughput detection of bulge defects with high resolution and accuracy, enabling effective identification and classification of defects on semiconductor wafers.
Implementation Method 1
generating coherent light that has a wavefront
Implementation Method 2
a probe beam of the coherent light with the shaped wavefront is directed onto an inspection surface of a wafer to thereby cause a reflection beam to be reflected from the inspection surface
Data Source
AI summary
A method includes generating coherent light that has a wavefront, shaping the wavefront of the coherent light to provide the coherent light with a shaped wavefront, directing a probe beam of the coherent light with the shaped wavefront to an inspection surface of a wafer, causing a reflection beam to be reflected from the inspection surface of the wafer, capturing an image formed from the reflection beam reflected from the inspection surface of the wafer and generating image data related to the image, and analyzing the image data to determine whether there is a defect in the inspection surface of the wafer.