Electrostatic Chuck Gas Release for Accurate Substrate Bonding
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Solution Overview
Problem
The existing substrate bonding devices suffer from non-uniform force distribution and varying expansion speeds during substrate contact, leading to decreased bonding position accuracy due to electrostatic adhesion and gravity effects.
Innovation Solution
A substrate bonding system with first and second electrostatic chucks, a gas discharge unit, and a controller to manage gas discharge, allowing controlled release of substrates for uniform contact and high-precision bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the vacuum chuck releases the peripheral portion of the substrate, then the substrate can expand radially outward for bonding, but the vacuum chuck may attach to the attachment surface due to electrostatic force, causing non-uniform force distribution and varying expansion speeds
Solution Approach 1:
The electrostatic chuck is divided into multiple independent electrode regions (central electrode and peripheral electrodes) that can be controlled separately. This segmentation allows the central portion to be released while peripheral portions remain held, creating non-uniform holding forces that guide controlled radial expansion and prevent unwanted adhesion to the attachment surface.
Solution Approach 2:
Different regions of the electrostatic chuck apply different holding forces to different regions of the substrate. The peripheral electrodes maintain strong holding forces to prevent adhesion to the attachment surface, while the central electrode releases to allow expansion. This local differentiation of holding quality enables precise control of the expansion process and maintains bonding position accuracy.
2Stability of the object's composition
If the vacuum chuck holds the peripheral portion strongly, then the substrate remains stable, but the electrostatic force causes adhesion to the attachment surface when released
Solution Approach 1:
The harmful electrostatic adhesion effect is extracted and isolated to specific peripheral electrode regions that remain active during release. By concentrating the holding force in peripheral regions rather than uniformly across the entire chuck surface, the design allows the central substrate to expand freely while peripheral electrodes prevent adhesion to the attachment surface.
Solution Approach 2:
The peripheral electrodes act as intermediary elements that mediate between the vacuum chuck and the substrate peripheral portion. These electrodes maintain a controlled electrostatic field that prevents the substrate from adhering to the attachment surface while allowing the central portion to expand, thus eliminating the harmful adhesion effect.
3Productivity
If the substrate expands radially outward due to restoring force and gravity, then bonding is achieved, but the force distribution becomes non-uniform and expansion speed varies
Solution Approach 1:
The electrostatic chuck transitions from a static uniform holding state to a dynamic non-uniform holding state during release. By progressively deactivating electrodes from center to periphery, the system creates a dynamic expansion process where the substrate expands in a controlled wave pattern, maintaining uniform force distribution and consistent expansion speed across different regions.
Solution Approach 2:
The electrode release process follows a periodic or sequential pattern where electrodes are deactivated in a specific sequence (e.g., central electrode first, then peripheral electrodes progressively). This periodic action creates a controlled expansion rhythm that ensures uniform force distribution and prevents variations in expansion speed, thereby maintaining bonding position accuracy.
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 system ensures high positional accuracy and uniform bonding by using electrostatic chucks and controlled gas discharge, preventing adhesion forces and enabling precise contact without distortion.
Implementation Method 1
at least one first electrostatic chuck provided in a first region facing a peripheral portion of the first substrate
Implementation Method 2
at least one second electrostatic chuck that is provided in a second region inside the first region in the first substrate holding unit and holds a portion facing the second region in the first substrate
Implementation Method 3
a gas discharge unit that is provided in the second region of the first substrate holding unit and discharges gas toward the first substrate
Data Source
AI summary
A substrate bonder includes a gas discharge hole (1413c, 1423c) provided in a second region in a stage and a head, and a controller that controls a chuck drive unit and a gas supply unit (1492) to release holding of a substrate with an electrostatic chuck (1413, 1423) and discharge gas from the gas discharge hole (1413c, 1423c) in a state where a peripheral portion of the substrate is held by the electrostatic chuck before bringing central portions of the substrates into contact with each other. The stage and the head include grooves (1413d, 1423d) provided in the second region and communicating with the gas discharge holes (1413c, 1423c).