Charged Particle Beam Blanking Restart After Abnormality Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Charged particle beam writing apparatuses face issues with pattern formation defects due to electromagnetic field variations during writing operations, leading to potential mask scraps, especially when multiple irradiations occur in multi-beam writing processes.
Innovation Solution
A charged particle beam writing apparatus and method that includes a writing mechanism for irradiating multiple beams with blanking control, a control circuit for managing shot data, and a detector for interrupting writing upon abnormality detection, generating interrupt position information to minimize mask scraps by restarting from the interrupted position based on stored shot data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multi-writing is performed to reduce positional accuracy errors and connection accuracy errors, then manufacturing precision is improved, but the time required for writing increases and the risk of mask scrap due to electromagnetic field variations increases
Solution Approach 1:
The system performs preliminary actions by storing shot data and control data in advance before writing operations. When an electromagnetic field variation is detected, the system can immediately interrupt and restart from the stored data without losing progress, enabling multi-writing to be performed efficiently with reduced time loss.
Solution Approach 2:
The system implements feedback mechanisms by detecting electromagnetic field variations during writing operations and using this information to interrupt and restart writing as needed. This feedback loop ensures that multi-writing maintains high precision while minimizing time loss through intelligent interruption and resumption based on real-time conditions.
2Reliability
If the number of multi-writing shots is increased to reduce mask scrap, then reliability is improved, but the writing time increases
Solution Approach 1:
Shot data and control data are stored in advance, allowing the system to perform multiple writing shots reliably while maintaining high productivity. When interruptions occur, the pre-stored data enables rapid resumption without significant time loss, thus improving reliability without sacrificing productivity.
3Reliability
If writing is interrupted and restarted to suppress mask scrap, then reliability is improved, but the complexity of the control system increases
Solution Approach 1:
The system creates copies of shot data and control data in storage memory. These data copies enable reliable interruption and restart operations without requiring complex real-time calculations or control mechanisms, thus improving reliability while keeping the control system relatively simple.
4Reliability
If electromagnetic field monitoring is implemented to detect abnormalities, then reliability is improved, but the device complexity increases
Solution Approach 1:
The system replaces complex mechanical monitoring mechanisms with electronic detection methods. By using electronic means to detect electromagnetic field variations and automatically interrupting writing when abnormalities are detected, the system achieves high reliability with relatively simple implementation, avoiding the need for complex mechanical monitoring 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
This approach effectively reduces the occurrence of mask scraps by immediately interrupting writing upon abnormality detection and restarting from the precise interrupt position, thereby minimizing defects in pattern formation.
Implementation Method 1
accelerate thermal electrons emitted from the cathode
Implementation Method 2
A comparatively high voltage of several tens of kV or higher is applied across a cathode and an anode of the electron gun to accelerate thermal electrons
Implementation Method 3
The electron beams emitted from the electron gun are imaged on the mask via an electro-optical system including a plurality of apertures, deflectors, lenses, etc.
Implementation Method 4
Multibeams are blanking-controlled by a blanker (electrode pair) corresponding to each electron beam
Data Source
AI summary
According to one embodiment, a charged particle beam writing apparatus includes, a writing mechanism, a writing control circuit, a deflection operation control circuit configured to generate control data for controlling the blanking of each of the charged particle beams based on the shot data, a storage, a blanking control circuit configured to control the blanking based on the control data, and a detector. The writing control circuit is configured to, when the detector detects the abnormality during the writing, interrupt the writing, and generate interrupt position information at a position where the writing is interrupted based on the shot data which has been stored at the storage and is related to the control data that has not been used for controlling the blanking.