Annular Holding Table for Wafer Edge Suction
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Solution Overview
Problem
Existing holding tables for platelike workpieces, such as wafers, face issues with contaminants adhering to the workpiece and support plates, leading to potential contamination of transporting units and storage cassettes, and support plates with flaws cannot be reused due to suction failure and risk of breakage during processing.
Innovation Solution
A holding table design featuring an annular holding member with a suction opening and a discharge opening, where only the outer circumferential portion of the support plate is held under suction, reducing the risk of contamination and flawing, and using a conductive resin to prevent static adhesion, with a vacuum line connected to a vacuum source and a fluid line connected to a fluid source for cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the entire support plate contacts the holding surface, then handling is facilitated, but contaminants adhere to the support plate and workpiece
Solution Approach 1:
The holding table applies suction only to the annular holding surface at the outer circumference, while the central recess remains free of suction. This local quality approach allows the support plate to be held securely at its edges while the central area (prone to contaminant adhesion) remains uncontaminated, preventing contamination of transporting units and cassettes.
2Productivity
If heat processing is applied to a support plate with flaws, then processing is completed, but the support plate and workpiece may break
Solution Approach 1:
The holding table design prevents flaw formation in the support plate by avoiding suction application to the central recess area during holding. This beforehand protection eliminates the root cause (suction-induced flaws) that would later lead to breakage during heat processing, ensuring support plate strength is maintained throughout the entire process including heat treatment.
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 design effectively reduces the risk of contamination and support plate flawing, allowing for the reuse of support plates and preventing contamination of transporting units and cassettes, while maintaining the rigidity of the holding table through a metal base and resin annular holding member.
Implementation Method 1
an annular holding member having an annular holding surface for holding the outer circumferential portion of the platelike workpiece thereon... a suction opening exposed to the annular holding surface, a vacuum line having one end communicating with the suction opening and the other end connected to a vacuum source
Data Source
AI summary
A holding table for holding a platelike workpiece which includes a base and an annular holding member attached to the base. The annular holding member has an annular holding surface for holding the outer circumferential portion of the platelike workpiece thereon. Accordingly, a central recess is defined by the base and the annular holding member so as to be surrounded by the annular holding member. The annular holding member is formed with a suction opening exposed to the annular holding surface, a vacuum line having one end communicating with the suction opening and the other end connected to a vacuum source, a discharge opening exposed to the annular holding surface at a position radially outside of the suction opening, and a fluid line having one end communicating with the discharge opening and the other end connected to a fluid source.