Electrostatic Chuck Residual Charge Dissipation via Photoconductivity
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Solution Overview
Problem
Electrostatic chucks in semiconductor manufacturing face challenges in completely removing residual charges, leading to uneven electrostatic forces, substrate damage, and difficulties in substrate retrieval due to residual electrostatic forces, which interfere with subsequent chucking operations.
Innovation Solution
A method and apparatus that utilize a radiation emitter and diffuser to emit electromagnetic energy onto the substrate support surface, increasing its conductivity through photoconductivity, allowing residual charges to dissipate and facilitating easier substrate release by reducing surface charge density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional grounding or polarity reversal methods are used to remove charge, then substrate release is attempted, but residual charge remains causing uneven electrostatic forces
Solution Approach 1:
The patent changes the electrical state of the electrostatic chuck by applying a high voltage pulse that temporarily alters the charge distribution. This parameter change enables complete charge removal by creating a controlled electrical breakdown that dissipates residual charges uniformly across the chuck surface, resolving the contradiction between ease of substrate release and completeness of charge removal.
2Ease of operation
If high mechanical force is applied to separate substrate from chuck, then substrate removal is achieved, but substrate cracks or damage occurs
Solution Approach 1:
The patent replaces the mechanical force-based separation method with an electrical field-based method. By applying a controlled high voltage pulse to the electrostatic chuck, the substrate is released through electrical charge neutralization rather than mechanical force, eliminating substrate damage while achieving complete separation.
3Manufacturing precision
If residual charge accumulates on chuck, then electrostatic force becomes uneven, but subsequent chucking operations are interfered with
Solution Approach 1:
The patent applies a high voltage pulse to the electrostatic chuck between processing steps as a preliminary action to preemptively remove residual charges. This prevents charge accumulation that would cause uneven electrostatic forces and interferes with subsequent chucking operations, thereby maintaining both force uniformity and processing productivity.
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 approach effectively reduces residual electrostatic forces, minimizing substrate damage and improving de-chucking efficiency, while also extending the service life of the substrate support and reducing mechanical forces required for separation.
Implementation Method 1
A method and apparatus that utilize a radiation emitter and diffuser to emit electromagnetic energy onto the substrate support surface, increasing its conductivity through photoconductivity
Implementation Method 2
an electrostatic chuck is used as the fixture to hold the substrate against a supporting structure with an electrostatic force (clamping force)
Implementation Method 3
an inert gas, such as argon, is introduced into the chamber containing the electrostatic chuck and ionized into a plasma. The plasma may form a conductive path from the surface of the electrostatic chuck to a grounded chamber component
Data Source
AI summary
A method and apparatus for discharging a residual charge from a substrate support. In one example, a substrate support is provided that includes a body, an electrode disposed in the body, a radiation emitter and a diffuser. The body has one or more holes formed in a workpiece support surface, the workpiece support surface configured to accept a substrate thereon. The electrode is configured to electrostatically hold a substrate to the workpiece support surface. The radiation emitter is disposed in a first hole of the one or more holes formed in the workpiece support surface. The radiation emitter is configured to emit electromagnetic energy out of the first hole. The diffuser is disposed in first hole over the radiation emitter.