Electrostatic Substrate Holder Stator Electrode Design
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Solution Overview
Problem
Existing electrostatic substrate holders in the semiconductor industry face challenges with particle abrasion during rotation, limited movement sequences, and contamination in high-vacuum systems due to sliding contacts used for electrostatic holding forces.
Innovation Solution
An electrostatic substrate holder design with non-rotating electrodes located on the stator, decoupling electrostatic holding forces from mechanical movement, eliminating sliding contacts and minimizing particle emission, and enhancing mobility with a mechanical assembly that includes conductive bearings for efficient force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If sliding contacts are used to supply electrostatic holding force to the rotating substrate holder, then the substrate can be held and moved, but particle abrasion and contamination occur in vacuum systems
Solution Approach 1:
The patent extracts the electrostatic holding function from the rotating substrate holder and relocates it to the stationary stator. The stator now contains the electrostatic actuators that generate holding forces, while the rotor becomes a passive mechanical structure without electrical contacts. This separation eliminates sliding contacts and their associated particle generation.
Solution Approach 2:
The patent replaces the mechanical sliding contact system with an electrostatic field-based system. Instead of physical contacts that wear and generate particles, the invention uses electrostatic actuators in the stator to generate holding and movement forces through electric fields, eliminating mechanical wear.
2Duration of action of moving object
If the substrate holder rotates with electrodes, then electrostatic holding force can be maintained during movement, but sliding contacts generate particle abrasion
Solution Approach 1:
The electrostatic actuating function is extracted from the rotating rotor and placed in the stationary stator. The stator's electrostatic actuators remain fixed while the rotor rotates passively, eliminating the need for sliding contacts to supply power during rotation and thus preventing particle abrasion.
Solution Approach 2:
The patent introduces magnetic coupling as an intermediary mechanism to transmit rotational motion from the rotor to the substrate without requiring direct electrical contacts. The magnetic coupling allows the rotor to rotate while the stator's electrostatic actuators remain stationary, maintaining holding force without sliding contacts.
3Volume of moving object
If thinned substrates are used to reduce chip volume, then volume reduction is achieved, but substrate brittleness increases making handling difficult
Solution Approach 1:
The patent replaces mechanical gripping and handling methods with electrostatic holding forces. The electrostatic actuators in the stator generate distributed holding forces across the substrate surface, avoiding mechanical stress concentration points that could cause brittle thinned substrates to break during handling.
Solution Approach 2:
The patent changes the holding mechanism from mechanical contact forces to electrostatic field forces. This parameter change allows for uniform distribution of holding forces across the substrate, preventing localized stress that would cause brittle substrates to fracture during handling and processing.
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 solution reduces particle contamination, allows for more reproducible and extended movement sequences, and maintains cleanliness in high-vacuum systems by separating electrostatic and mechanical functions, thereby improving the handling and processing of substrates.
Implementation Method 1
electrodes for generating an electrostatic holding force for fixing the substrate
Data Source
Figure 1~2c
Figure 3a~5
AI summary
The invention relates to an electrostatic substrate retainer (2) for holding and retaining a substrate (4), having: a rotor (6, 6', 6'', 6'''), which has a retainer (7, 7', 7'') for fastening the substrate (4) on a retaining surface (7h, 7h', 7h''), a stator (5, 5', 5'', 5''', 5iv) for holding and supporting the rotor (6, 6', 6'', 6'''), electrodes (11, 11', 11'') for producing an electrostatic retaining force for fastening the substrate (4), the stator (5, 5', 5'', 5''', 5iv) comprising the electrodes (11, 11', 11'').