Focused Charged Beam Support for Flat Substrate Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing focused charged particle beam processing apparatuses risk foreign object adhesion or damage to the lower surface of substrates like photomasks or circuit substrates, leading to failures in flat panel display production.
Innovation Solution
A focused charged particle beam apparatus with a support system that keeps the substrate horizontal, using a differential pumping device and local depressurizing mechanism to maintain substrate stability and prevent contact with foreign objects, combined with a positive pressure chamber to counteract substrate deflection and a gas ejection system to create a protective gas curtain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the substrate is placed directly on the mount base, then the processing operation can be performed, but foreign objects may be adhered to the lower surface of the substrate or the mount base may cause physical damage to the lower surface
Solution Approach 1:
The patent introduces a differential pumping device as an intermediary component between the substrate and the mount base. This device creates a localized vacuum region that allows the substrate to be processed without direct contact with the mount base, thereby preventing foreign object adhesion and physical damage while maintaining processing capability
Solution Approach 2:
The patent extracts the substrate from direct contact with the mount base by using the differential pumping device to create a suspended state. The substrate is held in position by the vacuum field rather than mechanical support, removing the harmful contact element while preserving the processing function
2Reliability
If a large-sized vacuum chamber is used to accommodate the substrate and focused ion beam device, then the substrate can be processed, but the apparatus size becomes large
Solution Approach 1:
The patent segments the vacuum environment into a large external atmosphere and a small localized vacuum region created by the differential pumping device. Only the immediate processing area around the substrate requires vacuum conditions, while the rest of the chamber remains at atmospheric pressure, dramatically reducing the required chamber size
Solution Approach 2:
The patent applies vacuum conditions locally only where needed for the focused ion beam processing, rather than maintaining vacuum throughout the entire chamber. The differential pumping device creates a localized vacuum zone that encompasses only the substrate and beam interaction region, minimizing the vacuum chamber volume required
3Ease of operation
If the substrate is supported only at the periphery, then the substrate can be accessed by the differential pumping device, but the substrate may deflect due to its own weight
Solution Approach 1:
The patent applies positive pressure to the lower surface of the substrate through the positive pressure chamber to counteract the gravitational force and substrate weight. This upward pressure compensates for the lack of full peripheral support and prevents substrate deflection, maintaining flatness while allowing peripheral access
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 apparatus effectively prevents foreign object adhesion and damage to the substrate surface, ensuring reliable processing without substrate deformation or contamination.
Implementation Method 1
A positive pressure chamber is disposed below the substrate borne by the support. The positive pressure chamber works to exert a positive pressure on a whole of the process target area of the substrate to cancel deflection of the substrate arising from its own weight.
Implementation Method 2
The local depressurizing mechanism works to exert a negative pressure on a lower surface of the substrate to cancel a suction force created by the differential pumping device.
Implementation Method 3
a focused ion beam device equipped with a local exhaust ventilation system. The processing apparatus works to locally create a vacuum space using the local exhaust ventilation system
Implementation Method 4
a first floating pad may be arranged to surround an outer periphery of the differential pumping device and works to eject gas to the process target surface
Data Source
AI summary
A focused charged particle beam apparatus which includes a support which supports a substrate to be processed and a focused charged particle beam column equipped with a differential pumping device movable to a location facing a given area of a process target surface of the substrate. The support bears only a periphery of the substrate while keeping the substrate horizontal. A positive pressure chamber is disposed below the substrate borne by the support and works to exert a positive pressure on the whole of the process target area of the substrate to cancel deflection of the substrate arising from its own weight. A local depressurizing mechanism is arranged in the positive pressure chamber and placed out of contact with the substrate. The local depressurizing mechanism works to exert a negative pressure on a lower surface of the substrate to cancel a suction force created by the differential pumping device. The local depressurizing mechanism is movable relative to the substrate following movement of the differential pumping device while facing the differential pumping device through the substrate.