Spatially Coherent Light Source for Deep Semiconductor Defect Detection
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Solution Overview
Problem
Current defect detection techniques, such as e-beam and bright field inspection, are limited in their ability to penetrate deeply into semiconductor packages, making it difficult to detect defects in advanced semiconductor packaging (ASP) where active circuit elements are buried deep within the substrate or package.
Innovation Solution
The use of a spatially coherent light source combined with a unique projection architecture that allows for unity magnification at any working distance, enabling the detection of defects deep within semiconductor packages by generating electronic maps indicating defects and their characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If e-beam or bright field inspection is used for defect detection, then high resolution sub 100 nm can be achieved at the top surface, but the inspection cannot penetrate deeply into the IC package beyond a few microns
Solution Approach 1:
The patent changes the fundamental parameter of light penetration by using deeply penetrating radiation (X-rays or gamma rays) instead of visible light or e-beam. This parameter change enables the radiation to traverse through the entire IC package including advanced semiconductor packaging with depths exceeding 750 microns, while maintaining defect detection capability through specialized detectors and image processing techniques
Solution Approach 2:
The patent replaces the mechanical/electronic inspection systems (e-beam, bright field microscopy) with a radiation-based inspection system. This substitution uses deeply penetrating electromagnetic radiation that can pass through packaging materials and deep substrate structures, fundamentally changing the inspection approach from surface-level to volumetric defect detection
2Reliability
If traditional front-end inspection methods are used, then defects in outer layers can be detected, but defects in buried active circuit elements deeper than 10 microns cannot be detected
Solution Approach 1:
The patent changes the inspection parameter from surface-optical to deep-penetrating radiation, enabling detection of defects at depths greater than 750 microns in advanced semiconductor packaging. The system uses X-ray or gamma-ray sources with energies selected to optimize penetration through specific packaging materials while maintaining sufficient contrast for defect detection
Solution Approach 2:
The patent introduces deeply penetrating radiation as an intermediary that can traverse through the IC package structure. This radiation acts as a mediator that carries information from deep buried elements through the packaging materials to external detectors, enabling non-destructive inspection of previously inaccessible regions
3Productivity
If advanced semiconductor packaging with deep substrate integration is used, then overall density and bandwidth are increased, but defect detection capability is reduced
Solution Approach 1:
The patent changes the detection parameter to deeply penetrating radiation that can access buried elements in advanced packaging structures. The system accommodates varying package depths (including stacked and bonded chips) by adjusting radiation energy and using computational imaging techniques to maintain detection capability across different structural configurations
Solution Approach 2:
The patent creates a universal inspection system that can handle multiple packaging types and depths. The deeply penetrating radiation system is adaptable to various advanced semiconductor packaging configurations including wafer-level packaging, chip stacking, and embedded devices, providing a single solution that works across different product architectures
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
This approach allows for the detection of minor submicron cracks in solder joints, critical cracks in Si die, and direct metal to metal bonds, as well as defects in copper traces and interconnections, with high accuracy and resolution, even at depths greater than 3 microns from the package surface.
Implementation Method 1
a light emitting device that outputs a light beam capable of penetrating a device under test at least to a first depth, wherein the light beam, upon initial output, comprises spatially coherent light waves
Implementation Method 2
a video detection chain that transforms light waves that were incident on the device under test into visible optical light
Data Source
AI summary
A defect detection system comprising of an incoherent light source and a collimating light source attachment to produce spatially coherent light waves (e.g., X-rays) that are capable of deeply penetrating a device under test (e.g., a semiconductor). Changes in the spatial coherence of the light waves incident upon the device under test may be utilized to generate one or more electronic maps that indicate one or more physical gauges for length, area, or volume, one or more concentration of elements or distributions in space, and one or more defects within the device under test, such as, cracks, breaks, gaps, and/or air pockets within the device under test.