Electron Beam Writing with Fixed-Potential Secondary Electron Suppression
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Solution Overview
Problem
In electron beam writing, positional deviations occur due to secondary electrons returning to the target object, causing irradiation position deviations, which existing methods struggle to correct effectively, especially with changing potential distributions and charge effects.
Innovation Solution
An electron beam writing apparatus and method that employs a potential regulating member with a fixed positive potential, preventing secondary electrons from returning to the target object by maintaining a constant electric field, and using correction circuits to accurately correct positional deviations during writing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an electrostatic lens with variable positive potential is used to prevent secondary electron return, then secondary electron return is reduced, but the potential distribution changes during writing, making positional deviation correction difficult
Solution Approach 1:
The patent divides the potential regulation function into two independent parts: a potential regulating member with fixed positive potential to prevent secondary electron return, and a separate correction circuit to correct positional deviations. This segmentation allows each component to perform its function independently without interfering with the other, resolving the contradiction between preventing electron return and maintaining correction accuracy.
Solution Approach 2:
The potential regulating member is set to a fixed positive potential to create an equipotential region that prevents secondary electrons from returning to the target object. By maintaining a constant potential rather than a variable one, the electric field remains stable, enabling accurate positional deviation correction while still preventing electron return.
2Productivity
If multiple beams are used to increase writing throughput, then productivity is improved, but positional deviations occur due to charging effects that are difficult to correct
Solution Approach 1:
The patent introduces a potential regulating member as an intermediary component between the electron beams and the target object. This intermediary creates a stable electric field that prevents charging effects from causing positional deviations, allowing multiple beams to operate simultaneously without the precision problems that would otherwise occur with high-speed writing.
3Object-affected harmful factors
If a fixed positive potential is applied to prevent secondary electron return, then secondary electron return is prevented, but positional deviations still occur due to charge effects
Solution Approach 1:
The patent employs a correction circuit that measures the actual positions of electron beams and applies feedback corrections to compensate for positional deviations caused by charge effects. This feedback mechanism works in conjunction with the fixed potential system, allowing both functions to coexist: the fixed potential prevents secondary electron return while the feedback correction maintains positioning 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
Precise correction of positional deviations is achieved while preventing secondary electrons from returning, stabilizing the potential distribution and improving the accuracy of electron beam positioning on the target object.
Implementation Method 1
a potential regulating member arranged to be upstream of the target object in a case where the target object is placed on the stage, and configured to be set to have a fixed potential being positive with respect to the target object
Implementation Method 2
an emission source configured to emit an electron beam
Data Source
AI summary
An electron beam writing apparatus according to the present invention includes a potential regulating member arranged to be upstream of a target object in the case where the target object is placed on a stage, and configured to be set to have a fixed potential being positive with respect to the target object, a potential applying circuit configured to apply a voltage to the target object or the potential regulating member so that the potential regulating member has the fixed potential, and a correction circuit configured to correct a positional deviation of the electron beam on a surface of the target object which occurs in the case where the target object is irradiated with the electron beam in the state in which the potential regulating member has the fixed potential.