Wafer Conveyance Control Based on Contact-Region Particle Detection
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Solution Overview
Problem
Existing lithography apparatuses face challenges in accurately conveying objects at high speeds due to foreign particles adhering to the suction holding region, leading to potential slippage and distortion, which affects positioning and productivity.
Innovation Solution
A measurement device measures foreign particles on the object's surface, and a conveyer holds the object while contacting a part of its surface, with a controller controlling the conveyance based on specific foreign particles detected to ensure accurate positioning and prevent slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the object is conveyed at a high speed by the suction holding means, then the productivity is improved, but the object may slip off the suction holding means due to reduced frictional force from foreign particles
Solution Approach 1:
The system performs preliminary measurement of foreign particles on the object surface before conveyance. Based on the measurement results, the conveyance speed is predetermined and set in advance. This preliminary action allows the system to prepare appropriate conveyance parameters before the actual high-speed conveyance, preventing slippage while maintaining productivity.
Solution Approach 2:
The system uses measurement results of foreign particles as feedback to control the conveyance speed. The foreign particle measurement unit detects particles, and this information feeds back to the control unit, which then adjusts the conveyance speed accordingly. This closed-loop feedback mechanism ensures that conveyance parameters are optimized based on actual surface conditions, preventing slippage while maintaining high productivity.
2Loss of time
If the object is conveyed at a high speed, then the time taken to convey the object is shortened, but the relative position between the suction holding means and the object deviates
Solution Approach 1:
The system performs preliminary measurement of foreign particles and predetermined the conveyance speed before actual conveyance. This advance preparation ensures that the conveyance parameters are optimized for the specific object surface conditions, allowing high-speed conveyance without position deviation.
Solution Approach 2:
The system changes the conveyance speed parameter based on foreign particle measurement results. When foreign particles are detected, the conveyance speed is adjusted to appropriate levels. This dynamic parameter adjustment allows the system to maintain positioning precision while minimizing conveyance time, resolving the contradiction between speed and accuracy.
3Reliability
If foreign particles are sandwiched between the suction holding means and the object, then the object may be distorted, but measuring all foreign particles increases device complexity
Solution Approach 1:
The system applies foreign particle measurement specifically to the contact region where the suction holding means contacts the object, rather than measuring the entire object surface. This localized measurement approach focuses resources on the critical area where particles would cause distortion, maintaining object integrity while minimizing device complexity.
Solution Approach 2:
The system uses an intermediary measurement approach where the foreign particle measurement unit detects particles in the contact region, and this measurement information mediates the control of conveyance speed. This intermediary measurement and control strategy prevents object distortion without requiring complex comprehensive measurement systems.
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 enables precise and efficient conveyance of objects by adjusting conveyance speed based on foreign particle distribution, preventing slippage and distortion, thereby enhancing productivity and accuracy.
Implementation Method 1
a conveyance apparatus that conveys an object such as an original or a substrate while holding the object by vacuum suction
Data Source
AI summary
The aspect of the embodiments, provides an apparatus comprising: a measurement device configured to measure foreign particles on a surface of an object; a conveyer including a holder configured to hold the object while contacting a part of the surface of the object, and configured to convey the object for which the foreign particles have been measured, while holding the object by the holder; and a controller configured to control conveying the object by the conveyer, in accordance with specific foreign particles in a contact region to which the holder contacts among the surface of the object, wherein the specific foreign particles are obtained from a measurement result of the measurement device.