Semiconductor Lead Notch Inspection via Laser Height Measurement
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Solution Overview
Problem
The existing technologies fail to accurately inspect and manage the shape of the notch region at the distal end of semiconductor leads with a wettable flank structure, leading to inconsistent solder bonding characteristics and potential connection failures during mounting on circuit boards.
Innovation Solution
A semiconductor inspection apparatus that includes a light source, an imaging device, and calculators to capture and analyze the silhouette images of the leads, calculating the areas and ratios of notch regions to ensure proper shape management and area balance, thereby determining the quality of the semiconductor package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection is performed on the notch region of the lead, then the shape management capability is improved, but the measurement precision is insufficient to accurately capture the notch region geometry
Solution Approach 1:
The patent transitions from conventional 2D imaging to 3D measurement by introducing a laser displacement meter that measures height information. The laser beam is irradiated onto the notch region from the upper surface side, and the displacement meter detects the height of the notch region bottom surface, thereby obtaining three-dimensional geometric information that cannot be captured by traditional visual inspection systems.
Solution Approach 2:
The patent replaces conventional optical imaging systems with a laser-based measurement system. Instead of using cameras and image processing to infer notch geometry, the system directly measures the physical height of the notch region bottom surface using a laser displacement meter, providing more accurate and direct measurement data.
2Reliability
If the notch region shape is not properly controlled, then the manufacturing process is simpler, but the solder bonding reliability deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the measured height of the notch region bottom surface is compared against a predetermined standard value. The inspection apparatus determines whether the semiconductor device passes or fails based on whether the measured height falls within the acceptable range, providing closed-loop quality control that ensures consistent solder bonding reliability.
Solution Approach 2:
The patent replaces subjective visual inspection with objective laser-based height measurement. By directly measuring the physical dimension of the notch region and comparing it to predetermined standards, the system eliminates variability in human judgment and provides consistent, reliable quality assessment that directly correlates with solder bonding performance.
3Measurement precision
If conventional imaging methods are used, then the inspection system is simpler, but the area balance of notch regions cannot be accurately calculated
Solution Approach 1:
The patent adds the height dimension to the inspection process by using a laser displacement meter to measure the depth of the notch region bottom surface from the upper surface. This three-dimensional measurement capability enables accurate calculation of notch region volume and area balance, which cannot be achieved with conventional two-dimensional imaging methods alone.
Solution Approach 2:
The patent integrates multiple measurement functions into a single inspection apparatus. The system can measure both the planar dimensions (width and length) of the notch region using imaging methods and the height/d depth of the notch bottom surface using laser displacement measurement, providing comprehensive geometric characterization in one unified system.
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 enables accurate measurement and management of the notch region shape, ensuring stable bonding characteristics and preventing connection failures by maintaining the appropriate area balance of the notch regions, thus enhancing the reliability of solder bonding.
Implementation Method 1
a light source irradiating a semiconductor package with inspection light
Implementation Method 2
an imaging device capturing a first image of the first lead, the semiconductor package being interposed between the imaging device and the light source
Data Source
AI summary
A semiconductor inspection apparatus of embodiments includes: a light source irradiating a semiconductor package, the semiconductor package including: a sealing portion having an upper surface, a lower surface, a first side surface, and a second side surface; and a first lead extending from the first side surface, the first lead having a first wide width portion and a first narrow width portion, the first wide width portion being between the first side surface and the first narrow width portion; an imaging device capturing a first image of the first lead; a first calculator calculating a first area of a first notch region located on one side of the first narrow width portion and a second area of a second notch region located on the other side of the first narrow width portion; and a second calculator calculating a ratio of the first area and the second area.