Bonded Wafer Optical Crack Detection for Bonding Energy Measurement
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Solution Overview
Problem
Conventional methods for measuring bonding energy in semiconductor manufacturing are inaccurate due to the influence of ambient humidity, which causes stress corrosion, and the use of glove boxes introduces additional challenges such as limited workspace, ergonomic issues, and increased costs.
Innovation Solution
A method and system that uses a light detector to record video of the bonded wafer during the test, determining crack length through peak finding algorithms and interferometry, allowing for accurate bonding energy measurements without a glove box, by measuring the bonding energy before ambient humidity affects the results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional spectroscopy or tensiometry methods are used to measure bonding energy, then measurement accuracy is improved under controlled conditions, but the cost increases and the ability to simulate real-world conditions is lost
Solution Approach 1:
The patent replaces complex mechanical measurement systems (spectroscopy equipment, tensiometry devices) with a simple optical detection system using a light detector and camera to measure crack propagation. This substitution maintains measurement capability while dramatically reducing system complexity and cost, allowing measurements in ambient conditions without requiring controlled environments.
Solution Approach 2:
The patent changes the measurement parameter from direct bonding energy measurement under controlled conditions to crack length measurement under ambient conditions. By using optical detection to track crack propagation and applying fracture mechanics principles, the system determines bonding energy indirectly through crack behavior, enabling measurements in real-world environments.
2Reliability
If glove boxes are used to control ambient humidity during measurement, then measurement reliability is improved, but workspace limitations and productivity decrease
Solution Approach 1:
The patent performs the critical measurement action quickly before ambient humidity can affect the bonded wafer. By using high-speed optical detection to capture crack propagation immediately after blade insertion, the system obtains reliable bonding energy data before stress corrosion from humidity degrades the bond, eliminating the need for glove boxes and increasing productivity.
Solution Approach 2:
The patent rushes through the measurement process by capturing crack length data in real-time during rapid crack propagation, completing the measurement before environmental factors like humidity can influence the results. This approach skips the need for prolonged controlled environment exposure while maintaining measurement reliability.
3Device complexity
If crack length is measured manually or with less precise methods, then device complexity is reduced, but measurement precision of crack length and bonding energy decreases
Solution Approach 1:
The patent replaces manual or simple mechanical crack measurement methods with optical detection using a light detector and camera. This substitution provides precise crack length measurement by detecting light intensity changes across the crack, achieving high measurement precision while keeping the overall device relatively simple and avoiding the need for complex controlled environment equipment.
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
The method provides accurate and reproducible bonding energy measurements in ambient conditions, reducing costs and increasing throughput by avoiding the limitations of glove boxes and improving the precision of crack length determination.
Implementation Method 1
passing light beams through the crack at an outer edge of the bonded wafer, and collecting light beams transmitting through the crack at a light detector
Implementation Method 2
determining the bonding energy of the bonded wafer based on a light intensity of the collected light beams
Implementation Method 3
determining crack length through peak finding algorithms and interferometry
Data Source
AI summary
A method of determining a bonding energy of a bonded wafer includes receiving the bonded wafer including a first wafer bonded with a second wafer, and inserting a blade between the first wafer and the second wafer to form a crack between the first wafer and the second wafer, the crack extending from a portion of the blade contacting the first wafer and the second wafer to a point where the first wafer and the second wafer are still bonded. The method further includes passing light beams through the crack at an outer edge of the bonded wafer, and collecting light beams transmitting through the crack at a light detector. And the method further includes determining the bonding energy of the bonded wafer based on a light intensity of the collected light beams.