Wafer Position Detection Using a Fluid-Pressure Trigger Assembly
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Solution Overview
Problem
Existing wafer position detection methods, such as lever braking type sensors and optical sensors, cause surface defects, are limited in application scope and accuracy, leading to yield rate issues and potential wafer breakage during handling.
Innovation Solution
A wafer position detection device using a trigger component with a top cover that moves to block or open a fluid delivery port based on wafer presence, combined with a fluid pressure detection component to determine proper positioning, ensuring indirect contact and reducing contact area and rotation to prevent scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lever braking type sensors are used for indirect detection, then wafer position detection is achieved, but surface defects occur due to component friction and complex structure
Solution Approach 1:
The patent introduces a magnetic field as an intermediary between the sensor and the wafer. The magnetic sensor detects changes in magnetic field distribution caused by the wafer's position, rather than directly contacting the wafer. This intermediary approach enables position detection while avoiding direct mechanical contact that would cause surface defects.
Solution Approach 2:
The patent replaces the mechanical lever braking type sensor with a magnetic sensor system. Instead of using mechanical components that physically contact the wafer, the system uses magnetic field detection to sense wafer position, thereby eliminating mechanical friction and associated surface damage.
2Measurement precision
If optical sensors are used for direct detection, then detection accuracy is improved, but application scope is limited for light-sensitive processes and false alarms occur due to polishing fluids
Solution Approach 1:
The patent substitutes optical detection with magnetic field detection. The magnetic sensor system is insensitive to polishing fluids and splashing droplets that interfere with optical sensors, while also being suitable for light-sensitive semiconductor processes. This substitution maintains detection accuracy while significantly expanding application versatility.
3Stability of the object's composition
If top cover contact area with wafer is increased, then stability is improved, but surface defects occur due to scratching
Solution Approach 1:
The patent uses air cushion technology to create a non-contact support system between the top cover and the wafer. Compressed air forms a cushion layer that provides stable support while eliminating direct mechanical contact, thereby preventing surface scratching while maintaining positional stability during wafer transfer.
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 improves yield rates by preventing surface defects and expanding application range to light-sensitive processes, while maintaining stability and reliability through linear movement guidance and pressure-based positioning adjustments.
Implementation Method 1
a fluid delivery pipeline arranged in a hollow cavity formed in an inner wall of the top cover; when a wafer is arranged on the top cover, the top cover moves in the direction close to the fluid delivery pipeline to block a fluid delivery port of the fluid delivery pipeline; and when no wafer is arranged on the top cover, the top cover moves in the direction away from the fluid delivery pipeline under fluid pressure
Implementation Method 2
a fluid pressure detection component connected with a control device and used for detecting the fluid pressure of the fluid delivery pipeline
Data Source
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AI summary
Disclosed in the present invention is a wafer position detection device. The wafer position detection device comprises a mounting seat, a trigger assembly and a fluid pressure measurement assembly. The trigger assembly arranged on the mounting seat comprises a top cover that protrudes out of a surface of the mounting seat and is used for supporting a wafer, and a fluid conveying pipeline arranged in a hollow cavity formed by an inner wall of the top cover, wherein when a wafer is arranged on the top cover, the top cover can move close to the fluid conveying pipeline to block a fluid conveying port of the fluid conveying pipeline; and when no wafer is arranged on the top cover, the top cover can move away from the fluid conveying pipeline under the action of a fluid pressure to be in communication with the fluid conveying port of the fluid conveying pipeline. The fluid pressure measurement assembly is in indirect contact with a wafer by means of the top cover, so as to indirectly detect the in-place condition of the wafer, and therefore, the problem of the influence on the yield caused by defects generated on the surface of a wafer due to direct contact is prevented. Compared with an optical sensor, the wafer position detection device can realize in-place detection of a wafer which is sensitive to illumination, and has a wide application range, and the universality of the device is improved.