Die Orientation Detection Using Inverted Translucent Imaging
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Solution Overview
Problem
Existing methods for determining the orientation of dies, such as flip chip LED dies, face challenges due to orientation features being located on the bottom surface or within the die, making it difficult to capture clear images as light is refracted or scattered by translucent layers, resulting in poor image quality and inaccurate orientation determination.
Innovation Solution
An apparatus with an imaging device and a light source arranged on opposite sides of the tape, where the light source projects light directly to the imaging device, allowing the orientation feature to obstruct the light and improve image clarity, enabling real-time inspection without removing the die from the tape, and potentially using a holding unit with a diffuser to reduce distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a down-look camera is used to capture images of orientation features on the die, then the imaging setup is simple, but the image quality is poor due to light refraction and scattering by translucent layers
Solution Approach 1:
The patent inverts the traditional imaging arrangement by placing the light source above the die and the camera below the tape, rather than both on the same side. This allows light to pass through the translucent die and be blocked by the opaque orientation features, creating high-contrast images that clearly reveal orientation markers despite the die's translucency
Solution Approach 2:
The patent introduces the tape as an intermediary medium that supports the die during inspection. The tape provides a stable backing that allows the inverted imaging setup to work effectively, as the camera captures images through the tape and die from below, while the light source illuminates from above
2Illumination intensity
If light is projected onto the die to illuminate orientation features, then the features become visible, but light refraction and scattering by translucent layers reduce image quality
Solution Approach 1:
The patent reverses the traditional illumination-imaging configuration by placing the light source above the die and the camera below the tape. This inversion allows light to pass through the translucent die structure, and the opaque orientation features to block and define the light path, creating sharp, high-contrast images that clearly show orientation markers without the degradation caused by multiple refractions and scatterings
Solution Approach 2:
The patent extracts the essential function of orientation feature detection by using the inverted setup to create high-contrast silhouettes of the features. Rather than relying on reflected light that undergoes multiple refractions, the system captures the direct shadow pattern of the opaque features against the translucent die, isolating the orientation information from the complicating optical effects
3Measurement precision
If the die is removed from the tape for inspection, then clear images can be captured, but productivity decreases due to additional handling time
Solution Approach 1:
The patent enables the inspection system to work with the die in its existing mounted state on the tape. The inverted imaging configuration allows the camera to capture clear images of orientation features through the translucent die and tape from below, eliminating the need to remove or reposition the die for inspection, thus maintaining continuous production flow
Solution Approach 2:
The patent inverts the imaging approach to accommodate the die's mounted state on the tape. By placing the camera below the tape and illuminating from above, the system can capture high-quality images of orientation features without requiring the die to be removed, enabling in-line inspection that maintains productivity
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 setup enhances image quality by increasing light intensity and reducing noise, allowing for accurate orientation determination of dies during manufacturing, thereby increasing productivity.
Implementation Method 1
the projected light from the light source passing through the die is obstructed by the at least one orientation feature of the die to cause the captured image to include an image of the at least one orientation feature
Implementation Method 2
it may be more difficult to capture a clear image of the orientation features as the line of vision between the camera and the die may be blocked by the other parts of the die and/or by the tape on which the die is mounted
Implementation Method 3
the orientation features are located on a bottom surface of the die or within the die. In these cases, it may be more difficult to capture a clear image of the orientation features as the line of vision between the camera and the die may be blocked
Data Source
AI summary
An apparatus for determining an orientation of a die mounted on a tape includes an imaging device, a light source and a conveying mechanism. The die is at least partially translucent and includes at least one orientation feature indicative of the orientation of the die. In use, the conveying mechanism conveys the tape to position the die at an inspection position between the imaging device and the light source. The light source projects light to the imaging device and the imaging device captures an image. The projected light from the light source passing through the die is obstructed by the at least one orientation feature of the die to cause the captured image to include an image of the at least one orientation feature, whereby the orientation of the die may be determined.