Multi Beam Writing Defect Control via Orthogonal Blankers
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Solution Overview
Problem
Multi-beam writing apparatuses face challenges with defective beams that are continuously 'beam on' due to ineffective beam-off control or uncontrolled beam current, leading to inaccurate pattern writing and reduced throughput.
Innovation Solution
A multi-charged particle beam writing apparatus and method that includes a stage for mounting a target object, an emission unit for forming multiple beams, blankers for deflecting defective beams orthogonally, and a detection processing unit to identify and manage defective beams, allowing for position shifting during writing to avoid defective beam positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple beams are formed by passing a charged particle beam through an aperture member with multiple openings, then throughput is greatly increased, but the risk of defective beams increases due to structural complexity
Solution Approach 1:
The system divides the beam control into multiple independent blanking units, each corresponding to a specific beam direction or group of beams. Each blanking unit can independently deflect its associated beams, allowing selective elimination of defective beams while maintaining operational beams. This segmentation enables the system to handle beam defects locally without affecting the entire multi-beam system, thus maintaining high throughput while improving reliability.
Solution Approach 2:
The patent introduces blanking units as intermediary components between the aperture member and the target object. These blanking units act as mediators that can intercept and deflect defective beams before they reach the target, while allowing good beams to pass through unchanged. This intermediary mechanism provides a buffer that protects the writing process from defective beams without requiring complete system shutdown or reconfiguration.
2Manufacturing precision
If beam-off control is performed for each beam in a multi-beam system, then pattern writing accuracy is maintained, but complexity of the control system increases
Solution Approach 1:
The patent combines multiple blanking control functions into integrated blanking units that can handle multiple beams simultaneously. Instead of requiring separate control mechanisms for each individual beam, the system uses blanking units that can deflect groups of beams or specific beam directions through unified control. This merging approach maintains the ability to perform precise beam-off control for pattern accuracy while reducing the overall complexity of the control system.
Solution Approach 2:
The blanking units are designed with multi-functionality, serving both as beam deflectors for blanking control and as detection targets for defective beam identification. The same structural elements that perform beam deflection also facilitate the detection process, eliminating the need for separate dedicated components for each function. This universality reduces system complexity while maintaining precise control capabilities.
3Productivity
If a defective beam is continuously beam on, then throughput is maintained, but pattern writing accuracy deteriorates
Solution Approach 1:
The system incorporates detection units that continuously monitor beams for defects and provide feedback to the control system. When a defective beam is detected (such as a beam that should be off but remains on), the system receives immediate feedback and activates the corresponding blanking unit to deflect the defective beam. This feedback mechanism ensures that throughput is maintained by quickly identifying and correcting beam defects rather than shutting down the entire system, while pattern accuracy is preserved by eliminating the harmful continuous beam exposure.
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
Ensures accurate writing by eliminating defective beams and maintaining throughput by controlling and compensating for insufficient doses, preventing pattern inaccuracies and reducing the need for additional passes.
Implementation Method 1
an emission unit that emits a charged particle beam; an aperture member in which a plurality of openings are formed, and configured to form multiple beams by letting a region including a whole of the plurality of openings be irradiated by the charged particle beam
Implementation Method 2
a plurality of first blankers that respectively perform blanking deflection of a corresponding beam in multiple beams having passed through the plurality of openings of the aperture member
Data Source
AI summary
A multi charged particle beam writing apparatus according to one aspect of the present invention includes a plurality of first blankers to respectively perform blanking deflection of a corresponding beam in multiple beams having passed through the plurality of openings of the aperture member, a plurality of second blankers to deflect a defective beam in the multiple beams having passed through the plurality of openings of the aperture member to be in a direction orthogonal to a deflection direction of the plurality of first blankers, a blanking aperture member to block each of beams which were deflected to be in a beam off state by at least one of the plurality of first blankers and the plurality of second blankers, and a detection processing unit to detect a defective beam in the multiple beams having passed through the plurality of openings of the aperture member.