Electrostatic Clamp Charge Control for Clean Substrate Release
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Solution Overview
Problem
Existing electrostatic clamps for substrate processing face issues with charge buildup on substrates, leading to hindered declamping and potential contamination due to conductive materials exposed to process gases, and a less than robust conductive side coating over gaps between metal and ceramic components.
Innovation Solution
An electrostatic clamp system with a charge control assembly that includes a conductive structure isolated from the electrode assembly, extending through the conductive base to an upper surface of the ceramic body, allowing for reversible electrical connection to an external ground or voltage source, which helps in managing and monitoring substrate charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive material is provided on the outside sides of the electrostatic clamp to address substrate charge buildup, then substrate charge control is improved, but the conductive material is exposed to process gases leading to erosion and contamination
Solution Approach 1:
The patent introduces a charge control assembly as an intermediary component that provides conductive material only where necessary for charge control, isolated from direct exposure to process gases. This assembly acts as a mediator between the substrate and the electrostatic clamp body, allowing charge management functionality while protecting the conductive material from harmful gas exposure through strategic placement and isolation.
Solution Approach 2:
The electrostatic clamp is segmented into distinct functional zones: the electrode assembly for electrostatic clamping, the charge control assembly for charge management, and the ceramic body for structural support and gas barrier. This segmentation allows each component to perform its specific function optimally without interfering with or being damaged by other functions, particularly protecting conductive materials from gas exposure.
2Reliability
If side conductive material is used to cover the gap region between metal base and ceramic, then electrical continuity is improved, but the adhesive-based construction results in a less than robust conductive side coating
Solution Approach 1:
The patent replaces the mechanical/adhesive-based construction (using silicone or other adhesives to attach conductive material) with an integrated construction approach. The charge control assembly is formed as part of the ceramic body structure itself, eliminating the need for adhesives and providing a more robust, reliable connection that maintains electrical continuity without the weaknesses of adhesive-based joints.
3Force
If electrostatic clamp is used for substrate processing, then substrate holding capability is improved, but undue charge accumulates on the substrate hindering declamping
Solution Approach 1:
The charge control assembly provides feedback control of substrate charge by continuously monitoring and adjusting charge levels during the substrate processing cycle. This feedback mechanism allows the system to maintain optimal charge levels for strong substrate holding during processing, then reduce or neutralize charge when declamping is required, ensuring easy substrate release without manual intervention.
Solution Approach 2:
The electrostatic clamp system transitions from a static charge state to a dynamic charge control system. The charge control assembly enables real-time adjustment of substrate charge levels, allowing the system to adapt charge characteristics during different processing stages - maintaining high charge for secure holding during processing, then dynamically reducing charge for easy declamping, making the holding force controllable rather than fixed.
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 effectively reduces substrate sticking, improves positioning, prevents discharge or microarcs, and minimizes particle generation and yield loss by efficiently managing substrate charge during processing.
Implementation Method 1
electrostatic clamp system may include a conductive base and a ceramic body... The ceramic body may include an electrode assembly
Implementation Method 2
charge control assembly may define an electrically conductive structure that is isolated from the electrode assembly and extends through the conductive base
Data Source
AI summary
An electrostatic clamp system may include a conductive base; a ceramic body, having an inner side that is attached to the conductive base, and an outer side to face a substrate, the ceramic body including an electrode assembly; and a charge control assembly, the charge control assembly defining an electrically conductive structure that is isolated from the electrode assembly and extends through the conductive base to an upper surface of the outer side of the ceramic body.