Semiconductor Module Inspection Using Coaxial and Ring Illumination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical visual inspection apparatuses struggle to accurately detect defects on power semiconductor modules with surface irregularities due to wires, leading to poor defect detection accuracy and inability to completely exclude visually defective products.
Innovation Solution
A semiconductor inspection apparatus employing a combination of coaxial vertical illumination and ring illumination systems, where the coaxial vertical illumination system uses a first light source with a specific wavelength or white light and a half mirror, while the ring illumination system uses oblique light from a ring-shaped light source in various wavelength ranges to effectively inspect surface irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coaxial vertical illumination with single wavelength or white light is used, then the inspection apparatus can detect defects on flat surfaces, but defect detection accuracy deteriorates when inspecting surfaces with irregularities due to wires
Solution Approach 1:
The illumination system is segmented into multiple independent light sources, each emitting light at different wavelengths (blue, green, red, infrared). This allows selective use of appropriate wavelengths for different inspection scenarios - achieving high defect detection accuracy on flat surfaces while also adapting to surfaces with wire irregularities
Solution Approach 2:
The illumination system is designed with multi-functional capability to handle both flat surfaces and surfaces with irregularities. By incorporating multiple wavelength light sources and a ring-shaped LED array, the system can adapt its illumination characteristics to suit different inspection requirements, making it universally applicable across various semiconductor device types
2Measurement precision
If only coaxial vertical illumination is used, then the apparatus structure remains simple, but defect detection accuracy on irregular surfaces deteriorates
Solution Approach 1:
The system merges coaxial vertical illumination and ring-shaped oblique illumination into a single integrated inspection apparatus. This combination allows the system to maintain structural simplicity while achieving high defect detection accuracy on both flat and irregular surfaces by utilizing complementary illumination geometries
Solution Approach 2:
The illumination system enables parameter changes by switching between different wavelengths (blue, green, red, infrared) and different illumination geometries (coaxial vs. oblique). This flexibility allows optimization of defect detection accuracy for different surface types without requiring multiple separate apparatuses
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 combined illumination systems enhance defect detection accuracy by providing clear contrast images of flat and irregular surfaces, allowing for the identification of contaminants and flaws on power semiconductor modules, thereby excluding visually defective products.
Implementation Method 1
a half mirror that is arranged inside a second casing joined to the first casing, and that reflects part of light having been emitted from the first light source and having passed through the first casing to generate incident light that normally enters the inspection target
Implementation Method 2
a camera that is arranged on the same axis as an optical axis of the incident light and an optical axis of reflected light resulting from the incident light being reflected by the inspection target, and that images transmitted light having been transmitted through the half mirror
Implementation Method 3
a second light source that obliquely irradiates the inspection target with light in at least one wavelength range among a red band, a blue band, and an infrared range from a light source that is arranged in a ring shape around the optical axis of the incident light
Data Source
AI summary
A semiconductor inspection apparatus of this disclosure is a semiconductor inspection apparatus that performs a visual inspection of, as an inspection target, a semiconductor module on a surface of which a plurality of semiconductor devices connected to one another by a wire is mounted. This semiconductor inspection apparatus includes a first light source that is arranged in a first casing, emits light in a specific wavelength band or white light, and constitutes a part of a coaxial vertical illumination system for the inspection target, and a second light source that obliquely irradiates the inspection target with light in at least one wavelength range among a red band, a blue band, and an infrared range from a light source that is arranged in a ring shape around an optical axis of incident light of the coaxial vertical illumination system.