Non-Contact Semiconductor Package Testing Using Multi-Angle Illumination
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Solution Overview
Problem
Current semiconductor package testing methods fail to accurately detect non-wet defects between solder balls and ball lands in stacked semiconductor packages, which are critical for ensuring proper electrical connections and device performance.
Innovation Solution
A semiconductor package testing apparatus utilizing vertical and inclined illuminators and image capture units, along with color information from a color camera, to capture stereoscopic images and determine bonding states between solder balls and ball lands, enabling non-contact detection of defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional testing methods are used for stacked semiconductor packages, then the testing process is simple, but the detection accuracy of non-wet defects between solder balls and ball lands is insufficient
Solution Approach 1:
The testing apparatus is segmented into multiple independent illumination units (vertical illuminator and inclined illuminators) and multiple image capture units positioned at different angles. Each unit performs a specific function, and their combined data provides comprehensive defect detection capability without requiring a single complex testing system.
Solution Approach 2:
The patent introduces multi-dimensional imaging by capturing images from vertical and inclined directions simultaneously. This multi-angle approach adds spatial dimensionality to the inspection process, enabling detection of non-wet defects that cannot be detected from a single viewpoint, thereby improving measurement precision without excessive complexity.
2Loss of information
If single-angle imaging is used, then the imaging system is simple, but 3D information and bonding state detection capability are insufficient
Solution Approach 1:
The patent merges multiple image capture units positioned at different angles (vertical and inclined) to simultaneously capture images of the same target. By combining the information from these multiple viewpoints, the system reconstructs 3D information and bonding states without requiring an overly complex single-unit system.
Solution Approach 2:
The patent uses color information as an intermediary to infer bonding states. By analyzing color characteristics from multi-angle images, the system can determine whether solder balls are properly bonded to ball lands, converting visual information into diagnostic data without direct physical contact or complex measurement instruments.
3Productivity
If non-contact testing is implemented, then the testing process is fast and non-invasive, but the ability to detect subtle bonding defects is reduced
Solution Approach 1:
The patent employs periodic illumination from multiple angles with different characteristics (vertical and inclined illuminators alternating or simultaneously illuminating). This periodic multi-angle illumination enables rapid capture of comprehensive information, maintaining high productivity while improving defect detection precision through the accumulated multi-perspective data.
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 apparatus enhances test reliability by providing detailed 3D information and minimizing measurement errors, allowing for the accurate detection of non-wet defects and improving the overall testing process.
Implementation Method 1
a vertical illuminator to supply vertical illumination in the same axial direction as a measurement target
Implementation Method 2
an inclined illuminator to supply inclined illumination in a different axial direction from the measurement target
Implementation Method 3
the vertical illumination to illuminate the measurement target may travel along the same light path as the light reflected by the measurement target
Data Source
AI summary
An apparatus to test a semiconductor package includes a vertical illuminator to supply vertical illumination in the same axial direction as a measurement target and a vertical image unit to capture a vertical image of the measurement target so that a testing apparatus may 2-dimensionally determine information on the shape, size, or position of a solder ball. An inclined illuminator may supply inclined illumination in a different axial direction from the measurement target, and an inclined image capture unit may capture a side image of the measurement target so that the testing apparatus may 3-dimensionally determine information on a state of contact of the solder ball with the ball land. The inclined image capture unit may include a color camera using color information, thereby markedly increasing test reliability and yield.