Wafer Edge Imaging With Mirror Reflection and Single-Camera Inspection
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Solution Overview
Problem
Existing wafer inspection methods require large apparatus sizes and increased costs due to the use of multiple cameras and complex mechanisms, leading to potential equipment failures and inefficient inspection times.
Innovation Solution
A substrate imaging apparatus utilizing a rotary holding unit with a mirror member and a single camera to simultaneously image both the peripheral portion and end face of a substrate, eliminating the need for multiple cameras and complex mechanisms, thereby reducing size and cost while enhancing inspection precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple cameras are used to inspect peripheral portions of a wafer, then inspection coverage is improved, but apparatus size and cost increase
Solution Approach 1:
The patent combines multiple imaging functions into a single camera by using a mirror member that reflects light from different wafer surfaces (front surface, back surface, end face) to the same imaging device. This merging approach eliminates the need for multiple cameras while maintaining comprehensive inspection coverage of all wafer surfaces.
Solution Approach 2:
A single camera system is designed to perform multiple inspection functions by capturing images of different wafer surfaces through optical reflection. The imaging device universally inspects the front surface, back surface, and end face by receiving reflected light from appropriately positioned mirror members, making one device perform the work of multiple specialized cameras.
2Measurement precision
If multiple cameras are used for wafer inspection, then inspection completeness is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple imaging functions into a single camera system, eliminating the need for complex mechanisms to assemble and coordinate multiple cameras. The mirror members are positioned to reflect light from different wafer surfaces to the single imaging device, simplifying the overall system architecture while maintaining comprehensive inspection capability.
3Device complexity
If one camera is moved to inspect multiple surfaces, then apparatus complexity is reduced, but inspection time increases
Solution Approach 1:
The patent replaces mechanical movement of the camera with optical reflection using mirror members. The camera remains stationary while mirrors positioned at different angles reflect light from various wafer surfaces to the fixed imaging device. This substitution of mechanical positioning with optical path routing enables simultaneous multi-surface inspection without moving parts, maintaining both simplicity and speed.
4Area of stationary object
If a compact design is achieved with one camera, then apparatus size is reduced, but imaging capability may be compromised
Solution Approach 1:
The patent uses mirror members positioned at different spatial angles to reflect light from various wafer surfaces to the single camera. By utilizing three-dimensional optical path routing through strategically placed mirrors, the system captures images of the front surface, back surface, and end face simultaneously with a compact single-camera design, maintaining full imaging capability while reducing apparatus size.
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 achieves a compact design, decreases costs, and ensures efficient and precise inspection of substrate surfaces by using a single camera to image both the peripheral and end faces, minimizing equipment failures and improving inspection efficiency.
Implementation Method 1
a mirror member 43 having a reflecting surface 432 that opposes an end face We of the substrate W and a peripheral portion Wd of a back surface Wb, the reflecting surface 432 being inclined with respect to a rotation axis of the holding table 201
Data Source
AI summary
In one embodiment, a substrate imaging apparatus includes: a rotary holding unit that holds and rotates a substrate; a mirror member having a reflecting surface that opposes an end face of the substrate and a peripheral portion of a back surface of the substrate held by the rotary holding unit, the reflecting surface being inclined with respect to a rotation axis of the rotary holding unit; and a camera having an imaging device that receives both first light and second light through a lens, the first light coming from a peripheral portion of a front surface of the substrate held by the rotary holding unit, and the second light being a reflected light of second light which comes from the end face of the substrate held by the rotary holding unit and is reflected by the reflecting surface.