Wafer Holding Claw Notch Detection Throughput
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Solution Overview
Problem
Conventional disk holding apparatuses and defect/particle detecting systems face challenges in accurately detecting the notch position on silicon wafers due to obstruction by holding claws, leading to reduced detection efficiency and increased processing time, especially when trying to image both surfaces simultaneously.
Innovation Solution
The apparatus employs movable holding claws that abut to the outer circumference of the disk, allowing light to pass through notches without obstruction, enabling reliable notch detection and simultaneous imaging of both surfaces by rotating the disk with the center as a rotational axis, thus improving throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the slide arms hold the wafer at the notch part, then the wafer can be securely held, but the notch position cannot be detected due to obstruction by the holding part
Solution Approach 1:
The patent inverts the conventional approach by positioning the holding claws above the wafer surface rather than below it. This allows the light source and photodetector to detect the notch without obstruction from the holding mechanism, while the holding claws still securely grip the wafer outer circumference
Solution Approach 2:
The patent transitions the holding claws from a two-dimensional plane below the wafer to a three-dimensional position above the wafer surface. This spatial repositioning enables simultaneous wafer holding and optical access to the notch for detection
2Measurement precision
If the wafer is re-held to detect the notch, then the notch detection accuracy improves, but the processing time increases and throughput decreases
Solution Approach 1:
The patent enables continuous operation by allowing notch detection to occur during the same holding phase that secures the wafer. The holding claws maintain grip while the optical system detects the notch, eliminating the need for release and re-holding cycles
Solution Approach 2:
The patent performs notch detection during the initial holding phase before any wafer manipulation is needed. The holding claws position and secure the wafer, and the notch is detected in the same operational sequence, preparing the system for subsequent processing
3Measurement precision
If the wafer is turned around to image both surfaces, then complete surface inspection is achieved, but the processing time increases significantly
Solution Approach 1:
The patent positions imaging systems in three-dimensional space above and below the wafer, enabling simultaneous capture of both surfaces without physical manipulation. The holding claws maintain wafer position while cameras capture front and back surfaces in parallel
Solution Approach 2:
The patent combines multiple imaging operations into a single simultaneous action. Both front and back surface cameras operate at the same time during one holding phase, merging what would traditionally be separate sequential imaging steps
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 solution ensures reliable notch detection and reduces processing time by eliminating the need for re-holding or repositioning, allowing for simultaneous imaging of both surfaces without obstructing cameras, thereby enhancing detection efficiency and throughput.
Implementation Method 1
the light from the light source is made to pass through the notch (1A) into the light receiving part (91) without being blocked by the holding part (3a)
Data Source
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AI summary
A disc holding apparatus is provided with a plurality of movable holding claws (3), which have a holding section (3a) abutting to the outer circumference of a wafer (1) having a notch (1A) and are arranged in the circumference direction of the wafer (1). Since the wafer (1) is held by having each holding section (3a) on the inner edge side of each movable holding claw (3) abut to the outer circumference of the wafer (1), at the time of detecting the notch by a sensor composed of a light source and a light receiving section, even when one of the holding sections (3a) abuts to the outer circumference of the wafer (1) at a part where the notchexists, light from the light source is permitted to enter the light receiving section through the notch without being blocked by the holding section (3a). Even when the wafer (1) is held at the part where the notch exists, the wafer (1) is not required to be correctly held again and throughput is improved with a shortened process time.