Backside Imaging Inspection with a Light-Transmitting Stage
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Solution Overview
Problem
Existing imaging devices with laminated structures suffer from reduced detection sensitivity due to inspection light being affected by the wiring layer, and increased dead space on the wafer due to probe placement on the on-chip lens side.
Innovation Solution
The use of a backside irradiation type imaging device with a light-transmitting placing table and an inspection apparatus that moves the placing table vertically and horizontally to adjust the relative position of the irradiation device, allowing inspection light to enter the photodiodes without being affected by the wiring layer and reducing dead space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inspection light is irradiated from the front side (on-chip lens side), then the imaging device can be inspected, but the detection sensitivity is reduced due to the wiring layer affecting the inspection light
Solution Approach 1:
The patent inverts the traditional inspection approach by irradiating inspection light from the backside of the substrate (opposite to the wiring layer) rather than from the front side. This allows the inspection light to reach the photodiodes directly without being blocked or distorted by the wiring layer, thereby improving detection sensitivity while eliminating the harmful interference from the wiring layer.
Solution Approach 2:
The patent introduces a light-transmitting placing table as an intermediary component between the inspection light source and the imaging device. This placing table allows the inspection light to pass through while supporting the substrate, enabling backside irradiation without direct contact between the light source and the device, thus maintaining detection sensitivity while avoiding wiring layer interference.
2Measurement precision
If probes are placed on the on-chip lens side for inspection, then the imaging device can be tested, but the dead space on the wafer increases
Solution Approach 1:
The patent inverts the probe placement location from the front side (on-chip lens side) to the back side of the substrate. By placing probes on the backside where there are no obstructions, the patent eliminates the need to reserve space on the front side for probes, thereby reducing dead space on the wafer while maintaining inspection accuracy.
3Measurement precision
If a light-transmitting placing table is used for backside irradiation, then detection sensitivity is improved, but the device complexity increases
Solution Approach 1:
The patent designs the placing table to serve multiple functions: it supports the substrate during inspection, enables backside irradiation by transmitting light, and facilitates probe contact on the backside. By consolidating these functions into a single component, the patent improves detection sensitivity without proportionally increasing device complexity.
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
Improves detection sensitivity and reduces wafer space by enabling inspection light to directly reach the photodiodes, facilitating accurate defect detection and efficient use of the wafer surface.
Implementation Method 1
a light-transmitting placing table having a placing surface on which the inspection object is placed
Data Source
AI summary
An inspection apparatus for an inspection object having an imaging device to which light is incident from a surface opposite to a wiring layer is provided. The inspection apparatus includes a light-transmitting placing table having a placing surface on which the inspection object is placed so that the surface opposite the wiring layer of the imaging device faces the placing surface, a placing table operating part configured to move the placing table vertically and horizontally, and an irradiation device configured to irradiate inspection light to the imaging device through the placing surface. The placing table operating part changes a relative position of the irradiation device with respect to the inspection object placed on the placing surface by moving the placing table.