Electrostatic Chuck Multi-Zone Dielectric Warped Workpiece Clamping
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Solution Overview
Problem
Conventional electrostatic chucks face difficulties in properly attracting and clamping warped workpieces due to variations in warpage caused by previous processing, which affects the uniformity of the electrostatic attraction force.
Innovation Solution
The electrostatic chuck features a dielectric layer with multiple zones of different dielectric materials, where the electrostatic attraction force varies based on the composition of these zones, providing a greater clamping force in specific zones to effectively attract and clamp warped workpieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform dielectric layer is used in the electrostatic chuck, then the structure is simple and easy to manufacture, but the electrostatic attraction force is uniform and cannot properly clamp warped workpieces
Solution Approach 1:
The dielectric layer is divided into multiple zones with different dielectric materials or properties. Specifically, a first dielectric material is used in a first zone and a second dielectric material is used in a second zone, creating local variations in dielectric properties. This allows different regions to provide different electrostatic attraction forces, enabling reliable clamping of warped workpieces while maintaining a relatively simple overall structure.
2Force
If the electrostatic attraction force is increased to clamp warped workpieces, then the clamping force is sufficient, but the workpiece may be damaged or the uniformity of processing is affected
Solution Approach 1:
Different zones of the dielectric layer provide different electrostatic attraction forces tailored to the specific clamping needs of warped workpieces. The first dielectric material in the first zone and the second dielectric material in the second zone create localized force variations that clamp warped regions effectively without applying excessive uniform force that could damage the workpiece or affect processing uniformity.
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 clamping of warped workpieces by varying the electrostatic attraction force across the surface, effectively addressing the challenge of warpage-induced unevenness, allowing for secure holding during processing.
Implementation Method 1
the workpiece is attracted to a surface of the electrostatic chuck by an electrostatic attraction force developed between the workpiece and a dielectric layer of the ESC via an application of voltage applied to one or more electrodes residing below the dielectric layer
Data Source
AI summary
An electrostatic chuck for clamping a warped workpiece has a clamping surface comprising a dielectric layer. The dielectric layer has a field and one or more zones formed of differing dielectric materials. One or more electrodes are coupled to a power supply, and a controller controls a clamping voltage supplied to the one or more electrodes via the power supply. An electrostatic attraction force associated with each of the field and one or more zones of the dielectric layer of the electrostatic chuck is induced, wherein the electrostatic attraction force varies based on the dielectric material of each of the field and one or more zones. The electrostatic attraction force is greater in the one or more zones than in the field, therein attracting warped regions of the workpiece to the clamping surface and clamping the warped workpiece to the clamping surface across a surface of the warped workpiece.