Semiconductor Lead Floating Measurement Using Dual-Angle Imaging
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Solution Overview
Problem
Existing semiconductor inspection systems face challenges in accurately measuring the amount of floating of leads on semiconductor packages, leading to potential connection failures during mounting on printed circuit boards, as they rely solely on oblique length measurements which can result in errors due to lead length variations.
Innovation Solution
A semiconductor inspection system comprising a first imaging unit capturing images of leads from a perpendicular direction, a second imaging unit capturing images from an inclined direction, and a third calculation unit determining the amount of floating using both front and oblique lengths, along with mirrors and a camera to capture silhouette images, thereby accurately measuring lead displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only oblique length measurement is used, then inspection process is simple, but measurement precision deteriorates due to lead length variations
Solution Approach 1:
The patent transitions from single-dimension (oblique length only) to two-dimension (front length + oblique length) measurement by adding a perpendicular imaging unit. This dimensional expansion enables accurate floating amount calculation through geometric relationships, resolving the measurement precision issue while maintaining reasonable system complexity.
Solution Approach 2:
The patent introduces calculation units as intermediaries that process front length and oblique length measurements to compute the floating amount. These calculation units serve as mediators between raw measurement data and the final inspection result, enabling precise floating detection without directly increasing physical measurement complexity.
2Measurement precision
If perpendicular and inclined imaging units are added, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent designs imaging units with multi-functionality: the perpendicular imaging unit captures both front length and silhouette information, while the inclined imaging unit captures oblique length and floating characteristics. This universal design reduces overall system complexity by making each component perform multiple measurement functions simultaneously.
Solution Approach 2:
The patent uses optical copying through imaging units to create two-dimensional representations of the three-dimensional lead structure. By capturing silhouette images and length measurements from different angles, the system creates computational models that simplify the actual measurement process and reduce the need for complex physical measurement apparatus.
3Measurement precision
If dual-directional imaging is implemented, then inspection accuracy improves, but inspection time increases
Solution Approach 1:
The patent performs preliminary actions by capturing both perpendicular and inclined images simultaneously or in rapid succession before the inspection decision is made. The calculation units pre-process the image data to extract front length and oblique length, preparing the information needed for floating amount calculation, thereby reducing total inspection time.
Solution Approach 2:
The patent maintains continuous useful action by implementing an integrated imaging and calculation system that processes measurements without interruption. The perpendicular and inclined imaging units operate in coordination with calculation units to continuously monitor and determine lead floating, ensuring uninterrupted inspection flow and minimizing time loss.
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 system accurately measures the amount of floating of semiconductor leads, reducing errors associated with lead length variations and improving inspection throughput by using a combination of perpendicular and inclined imaging to calculate floating amounts accurately.
Implementation Method 1
a first imaging unit capturing an image of a first lead of a semiconductor package from a first direction perpendicular to an upper surface and a lower surface
Implementation Method 2
a second imaging unit capturing an image of the first lead from a second direction inclined with respect to the upper surface and the lower surface
Implementation Method 3
a first mirror provided on a lower surface side and the second side surface side of the semiconductor package, the first mirror reflecting a silhouette image of the first lead illuminated by the first light source
Data Source
AI summary
A semiconductor inspection system according to an embodiment includes first imaging unit capturing an image of a first lead of a semiconductor package from a first direction perpendicular to an upper surface, the semiconductor package including a sealing portion and the first lead, the sealing portion having the upper surface, the first lead extending sideward from the sealing portion; first calculation unit calculating a front length of the first lead from the image captured by the first imaging unit; second imaging unit capturing an image of the first lead from a second direction inclined to the upper surface; second calculation unit calculating an oblique length of the first lead from the image captured by the second imaging unit; and third calculation unit calculating an amount of floating of the first lead from a reference plane parallel to the upper surface, using the front length and the oblique length.