Charged Particle Beam Optical System Magnetic Field Cancellation
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Solution Overview
Problem
The exposure accuracy of charged particle beam systems, such as electron beam exposure apparatuses, deteriorates due to leaked magnetic fields generated by magnetic field controllers, which affect the precision of pattern formation on substrates during the lithography process.
Innovation Solution
The implementation of a charged particle beam optical system with multiple irradiation optical systems, where each generates a magnetic field with distinct characteristics, specifically by controlling the polarity of the magnetic fields to weaken the leaked magnetic fields, thereby reducing their impact on the exposure process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a magnetic field generator is used to control the charged particle beam, then the beam control capability is improved, but the exposure accuracy deteriorates due to leaked magnetic fields
Solution Approach 1:
Multiple irradiation optical systems are combined in a single exposure apparatus. Each optical system includes a magnetic field generator that produces magnetic fields with different characteristics (particularly different polarities). The leaked magnetic fields from these multiple systems interact and cancel each other out, reducing the net harmful magnetic field leakage while maintaining effective beam control capability.
Solution Approach 2:
The invention converts the harmful leaked magnetic fields into a beneficial effect by strategically designing multiple optical systems to generate magnetic fields with different characteristics. The leaked fields that would normally cause exposure errors instead cancel each other through destructive interference, transforming a harmful phenomenon into a mechanism that improves exposure accuracy.
2Manufacturing precision
If multiple irradiation optical systems are used, then the leaked magnetic fields are weakened through cancellation, but the device complexity increases
Solution Approach 1:
The exposure apparatus is segmented into multiple independent irradiation optical systems, each capable of generating charged particle beams with controlled magnetic fields. This segmentation allows each subsystem to be optimized independently while their combined operation achieves magnetic field cancellation, reducing overall exposure errors despite the increased number of components.
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
This approach effectively minimizes the influence of leaked magnetic fields, ensuring that the charged particle beam is accurately irradiated onto the substrate, thereby enhancing exposure accuracy and maintaining high precision in pattern formation.
Implementation Method 1
an exposure apparatus that is configured to control the charged particle beam by using a magnetic field generator (for example, an electromagnetic lens) configured to generate a magnetic field
Implementation Method 2
the plurality of irradiation optical system including a first irradiation optical system and a second irradiation optical system that generates a second magnetic field having a characteristics different from a characteristics of a first magnetic field generated by the first irradiation optical system
Data Source
AI summary
A charged particle beam optical system is provided with a plurality of irradiation optical systems each of which irradiates an object W with a charged particle beam EB, the plurality of irradiation optical system includes a first irradiation optical system and a second irradiation optical system that generates a second magnetic field having a characteristics different from a characteristics of a first magnetic field generated by the first irradiation optical system.