Substrate Transfer Hand Offset Control for Wafer Deflection
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Solution Overview
Problem
Existing substrate transfer systems face challenges in preventing damage to substrates due to contact when the substrate state changes, such as during stacking or deflection, as the existing systems do not effectively adjust for variations in substrate thickness or deflection.
Innovation Solution
A substrate transfer apparatus equipped with a hand, movement mechanism, and controller that includes a detection unit to adjust the offset amount of the hand's movement up and down from the substrate support height based on detected thickness or deflection, ensuring safe loading and unloading by determining planned advance and retreat heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed offset amount is used for hand movement, then the device complexity is reduced, but substrate damage risk increases when substrate thickness or deflection changes
Solution Approach 1:
The offset amount is changed dynamically based on detected substrate thickness or deflection. The controller adjusts the offset amount in real-time according to the actual substrate state, transforming a static control parameter into a dynamic one that adapts to varying substrate conditions, thereby preventing contact damage while maintaining operational simplicity.
Solution Approach 2:
The offset amount parameter is modified according to detected substrate characteristics (thickness or deflection). By changing this critical parameter based on actual substrate state, the system achieves adaptive control without requiring complex mechanical structures, resolving the contradiction between simplicity and safety.
2Manufacturing precision
If the hand moves closer to the substrate to improve transfer precision, then manufacturing precision is improved, but the risk of contact damage increases when substrate state varies
Solution Approach 1:
The detection unit measures substrate thickness or deflection, and the controller uses this feedback information to adjust the offset amount. This closed-loop feedback mechanism enables the hand to move precisely close to the substrate while automatically compensating for substrate state variations, achieving high precision transfer without contact damage.
Solution Approach 2:
The offset amount is adjusted in advance based on detected substrate characteristics before the hand approaches the substrate. This preliminary adjustment ensures that the hand is positioned at the optimal distance considering the specific substrate state, achieving precise transfer while preventing contact damage from the outset.
3Productivity
If substrate processing such as stacking is performed, then productivity is improved, but substrate deflection increases causing contact risk
Solution Approach 1:
Before substrate transfer operations, the detection unit measures the substrate state including any deflection from stacking processing. The controller then adjusts the offset amount in advance based on these measurements, enabling safe transfer operations even when substrates have undergone stacking or other processing that may cause deflection, thereby maintaining high productivity without contact damage.
Data Source
AI summary
A substrate transfer apparatus includes a hand that transfers a substrate from a cassette that accommodates substrates in multiple stages in a vertical direction; a movement mechanism that moves the hand; a controller that controls the movement mechanism; and a first detection unit that detects the substrate. The controller includes an offset amount change unit that changes an offset amount by which the hand is moved up and down from a substrate support height of the cassette when the hand loads and unloads the substrate with respect to the cassette, according to a thickness or a deflection amount of the substrate detected by the first detection unit.