Silicon Wafer Side Edge Imaging with Reflective Slit Optics

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Solution Overview

Problem

Existing silicon wafer side edge detection methods using a square prism result in a too bright photographic background due to multiple reflections, interfering with the imaging effect and making it difficult to accurately detect side edges.

Innovation Solution

A silicon wafer side edge detection device with first and second detection units, each comprising a point light source, reflective structure, and a slit, which reflects light from the light source to the side edge of the wafer and allows it to pass through the slit into a camera, improving imaging quality and simplifying mounting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a square prism is used to reflect or transmit light from a light source, then the light can be directed to the silicon wafer side edge, but multiple reflections from the bottom of the square prism result in a too bright photographic background, affecting the imaging effect

Engineering Contradiction:
Improvelight intensityVSAvoidimaging effect
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The optical path is divided into separate components: a reflective structure (such as a mirror or reflective plate) and a slit structure. This segmentation allows the light reflection function and the light filtering function to be separated, preventing multiple reflections from creating excessive background illumination while maintaining sufficient light intensity for imaging the silicon wafer side edge.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The harmful multiple reflections from the bottom of the square prism are eliminated by extracting this function and replacing it with a reflective structure combined with a slit. The slit specifically extracts and allows only the necessary light path while blocking stray light and multiple reflections, thus improving the imaging effect without sacrificing illumination intensity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a square prism is used for side edge detection, then light can be reflected or transmitted, but the mounting process is more complex compared to alternative structures

Engineering Contradiction:
Improvedetection functionVSAvoidmounting convenience
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The detection assembly is segmented into independent components: a reflective structure and a slit structure. This segmentation simplifies the mounting process as each component can be independently positioned and adjusted, reducing the complexity of assembly while maintaining the reliability of the side edge detection function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reflective structure acts as an intermediary element that simplifies the optical path design. Instead of using a complex square prism, the reflective structure directs light in a controlled manner, and the slit further refines the light path, making the overall mounting process simpler while ensuring reliable detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If a square prism is used for side edge detection, then light reflection can be achieved, but the structure is less suitable for large-scale industrial use due to mounting complexity

Engineering Contradiction:
Improveindustrial scalabilityVSAvoidmounting ease
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The detection device is divided into modular components (reflective structure and slit) that can be independently manufactured, tested, and assembled. This modularity significantly improves ease of operation during mounting and facilitates large-scale industrial deployment, as multiple units can be quickly installed and configured without complex alignment procedures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The optical path design is changed from a fixed square prism geometry to a flexible arrangement of reflective structure and slit. This parameter change allows for easier adjustment and optimization during mounting, improving ease of operation and making the system more suitable for large-scale industrial use where quick deployment and maintenance are critical.

Inventive Principle:
Principle #35Parameter changes

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 device enhances imaging effect by reducing excessive illumination, prevents overexposure, and facilitates easier mounting, making it suitable for large-scale industrial use.

Implementation Method 1

the reflective structure is configured to reflect light emitted by the first point light source and reflect the light to a side edge of a silicon wafer to be detected

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

the light is reflected by the side edge of the silicon wafer to be detected and passes through the slit into the camera

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentEP4618137A1Silicon wafer side edge detection device and silicon wafer sorting machine
Publication Date: 2025.09.17 WUXI AUTOWELL TECH
  • EP4618137A1 patent drawingFigure 1~2
  • EP4618137A1 patent drawingFigure 3~4
  • EP4618137A1 patent drawingFigure 5~7

AI summary

The present disclosure discloses a silicon wafer side edge detection device, comprising a first detection unit and a second detection unit, wherein the first detection unit and the second detection unit are of the same structure and are respectively configured to detect two mutually parallel side edges of a silicon wafer; and the first detection unit and the second detection unit each comprises a side edge detection assembly, the side edge detection assembly comprising a first point light source, a first optical path defining element, and a camera, wherein the first optical path defining element comprises a reflective structure and a slit, the reflective structure is configured to reflect light emitted by the first point light source and reflect the light to a side edge of a silicon wafer to be detected, and the light is reflected by the side edge of the silicon wafer to be detected and passes through the slit into the camera. The present disclosure not only solves the problem of an existing square prism affecting an imaging effect, but improves the imaging effect. The mounting of the first optical path defining element is also more convenient than the mounting of the square prism, so that it is more suitable for large-scale industrial use.