Electrostatic Chuck Tray Cooling via Segmented Electrodes
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Solution Overview
Problem
In semiconductor manufacturing equipment, the temperature of a tray used to convey wafers can rise significantly during plasma processes, leading to uneven wafer temperatures, decreased etching yields, and reduced throughput due to the tray's lack of electrostatic attraction and subsequent heat absorption.
Innovation Solution
An electrostatic chuck with a concave surface portion and embedded electrodes that attract and cool both wafers and trays, ensuring uniform temperature control and efficient heat transfer via gas channels and protruding portions, preventing tray temperature increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a tray is used to convey wafers on the electrostatic chuck, then wafer conveyance is enabled, but the tray temperature rises considerably higher than the wafer temperature because the tray is not attracted to the electrostatic chuck
Solution Approach 1:
The electrostatic chuck is designed to perform multiple functions: it attracts and holds both wafers in the chuck regions and the tray in the concave surface portion. By making the tray attractive to the electrostatic chuck through electrode arrangement, the system achieves universal attraction capability for different objects (wafer and tray), preventing the tray from overheating while maintaining its conveyance function.
2Productivity
If the tray temperature rises, then wafer peripheral temperature increases, but etching characteristic varies and yield decreases
Solution Approach 1:
The electrostatic chuck acts as an intermediary thermal management device between the heat source (plasma process) and the wafer-tray system. By attracting the tray and providing a controlled thermal environment, the chuck mediates heat transfer, preventing excessive heat from reaching the wafer peripheral regions and thus maintaining uniform etching characteristics.
3Ease of operation
If the tray temperature is high, then wafer conveyance becomes troublesome, but throughput decreases due to waiting for cooling
Solution Approach 1:
The electrostatic chuck performs preliminary cooling action on the tray by attracting it and maintaining it in a cooled state throughout the process. This preliminary thermal management ensures the tray remains at an appropriate temperature for easy wafer conveyance, eliminating the need to wait for cooling and thus maintaining high throughput.
4Force
If electrodes are arranged only in chuck regions, then wafer attraction is achieved, but tray temperature control is insufficient
Solution Approach 1:
The electrode arrangement is segmented into different functional zones: electrodes in the chuck regions for wafer attraction and electrodes in the concave surface portion for tray attraction and temperature control. This segmentation allows independent optimization of wafer handling and tray thermal management, solving the problem of tray overheating while maintaining effective wafer attraction.
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 maintains wafer temperature uniformity, reduces etching variations, and allows for immediate tray conveyance post-process, enhancing production efficiency and reliability by ensuring the tray remains cool and preventing thermal expansion issues.
Implementation Method 1
an electrostatic chuck which has a plurality of chuck regions, and in which a tray for conveying the wafers is arranged on a concave surface portion which is provided to an outer region of the chuck regions
Implementation Method 2
the dry etching equipment has the electrostatic chuck which is cooled such that a wafer temperature does not rise more than a regulation value by the plasma process
Data Source
AI summary
An electrostatic chuck includes, a chuck function portion including a plurality of chuck regions on which an attractable object is placed respectively, and a concave surface portion provided in an outer region of the chuck regions, and electrodes arranged in an inner part of the chuck function portion corresponding to the chuck regions and an inner part of the chuck function portion corresponding to the concave surface portion, respectively.