Bonded Wafer Inspection Using Diffuse Reflection and Dual-Path Radiation
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Solution Overview
Problem
Current semiconductor manufacturing methods lack effective means to monitor the quality of bonded wafer arrangements during production, leading to inefficiencies and defects in high-quality semiconductor device yield.
Innovation Solution
A method and system for inspecting bonded wafer arrangements using measuring radiation that interacts with the wafer and substrate, allowing for detection of defects and irregularities through imaging and analysis, including the use of a diffuse reflector and limited wavelength range to enhance image contrast and visibility of interferences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional manufacturing methods are used without inspection, then manufacturing process is simple and fast, but quality monitoring capability is poor leading to defects
Solution Approach 1:
A diffuse reflector is introduced as an intermediary component between the light source and the bonded wafer arrangement. The reflector diffuses the measuring light to illuminate the wafer from multiple angles, enabling detection of defects such as particles, voids, and adhesive layer issues without requiring complex multi-source illumination systems
Solution Approach 2:
The patent replaces complex mechanical inspection systems with an optical measurement system. By using measuring radiation (light) that interacts with the bonded wafer arrangement and detecting the emerging radiation, the system achieves quality monitoring through optical properties rather than mechanical contact or complex mechanical scanning
2Reliability
If comprehensive quality inspection is implemented, then defect detection capability is improved, but manufacturing time increases
Solution Approach 1:
The inspection is performed at an early stage in the manufacturing process, immediately after bonding the wafer to the substrate. This preliminary inspection identifies defects before subsequent processing steps, preventing waste of time and resources on defective wafers while maintaining fast overall manufacturing throughput
Solution Approach 2:
The optical measurement system enables continuous or near-continuous inspection during the manufacturing process. By using a diffuse reflector to illuminate the entire wafer surface uniformly and detecting radiation simultaneously across multiple locations, the system achieves comprehensive quality monitoring without requiring sequential scanning that would increase inspection time
3Measurement precision
If measuring radiation traverses the bonded wafer arrangement twice, then image contrast and visibility of defects is enhanced, but radiation intensity reaching detector is reduced
Solution Approach 1:
The patent changes the parameters of the measuring radiation by using a diffuse reflector to alter the illumination geometry. The diffused light provides multi-angle illumination that enhances interference patterns and image contrast when radiation traverses the wafer twice, while the increased path length is compensated by the distributed illumination from the diffuse reflector
Solution Approach 2:
The patent converts the potential harm of reduced radiation intensity into a benefit by using the double traversal to enhance image contrast and defect visibility. The measuring radiation that would normally be lost or weakened is instead used to create enhanced interference patterns that reveal defects, particles, and adhesive layer variations more clearly
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
Enables the identification of defects and irregularities in bonded wafer arrangements, allowing for informed decision-making in manufacturing processes, such as de-bonding defective wafers and avoiding unnecessary processing steps, thereby improving the yield of high-quality semiconductor devices.
Implementation Method 1
directing measuring radiation onto the bonded wafer arrangement, imaging at least a portion of the bonded wafer arrangement onto a detector using the measuring radiation emerging from the bonded wafer arrangement
Implementation Method 2
reflecting measuring radiation having traversed the bonded wafer arrangement and emerging from the back face of the bonded wafer arrangement back through the bonded wafer arrangement
Data Source
AI summary
A method of inspecting a bonded wafer 3 arrangement comprises:directing measuring radiation through the bonded wafer arrangement 3; imaging at least a portion of the bonded wafer arrangement onto a detector 19 using the measuring radiation having traversed the bonded wafer arrangement, wherein an object side numerical aperture δ of the imaging 16, 18 is less than 0.05; andsimultaneously detecting, using the detector 19, at least a portion of the measuring radiation having traversed the bonded wafer arrangement at a multitude of different spaced apart locations 23 within the field of view;wherein the detected radiation has an intensity spectrum such that an intensity of the detected radiation having wavelengths less than 700 nm is less than 10% of a total intensity of the detected radiation and an intensity of the detected radiation having wavelengths greater than 1200 nm is less than 10% of the total intensity of the detected radiation.