Charged Particle Beam Writing Deflection Correction
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Solution Overview
Problem
Conventional charged particle beam writing techniques face challenges in achieving precise deflection position correction due to substrate height distribution irregularities, leading to residual errors that are not adequately addressed by conventional methods, especially as pattern miniaturization requires sub-nanometer accuracy.
Innovation Solution
A charged particle beam writing apparatus and method that includes a measurement unit for substrate height position measurement, a height distribution correction unit to input position-dependent and time-dependent errors, and a deflection shift calculation unit to correct the beam's deflection amount, enabling precise pattern writing by adjusting the beam's path based on calculated corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deflection position correction is performed based on substrate height distribution, then writing dimension deviation is corrected, but residual position errors remain that cannot satisfy sub-nanometer accuracy requirements
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual written pattern position, calculating the deviation from the target position, and using this deviation information to correct the deflection position for subsequent writing. The measurement unit measures the written pattern, the calculation unit computes position deviations, and the deflection position correction unit adjusts based on these computations, creating a closed-loop feedback system that progressively reduces position errors to achieve sub-nanometer accuracy.
Solution Approach 2:
The patent replaces conventional mechanical/optical deflection position correction methods with a computational approach. Instead of relying solely on physical deflection adjustments based on height distribution, the system uses calculation units to compute position deviations from actual measurements and applies computational corrections to the deflection positions, substituting physical correction mechanisms with information-processing-based correction.
2Manufacturing precision
If multiple writing methods (e.g., double patterning) are used to achieve higher precision, then dimension accuracy improves, but writing time and process complexity increase
Solution Approach 1:
The patent enables the writing system to perform self-correction by measuring its own writing results and automatically adjusting deflection positions based on measured deviations. The measurement unit measures the written pattern, the calculation unit computes corrections, and the system applies these corrections autonomously without requiring external intervention or multiple writing passes, allowing single-step writing to achieve high precision.
Solution Approach 2:
By implementing real-time measurement and feedback correction within a single writing process, the system eliminates the need for multiple sequential writing operations. The feedback loop measures writing results and corrects position errors during the same writing cycle, reducing total writing time while maintaining high dimension accuracy.
3Productivity
If single writing is performed to reduce writing time, then productivity improves, but position accuracy becomes insufficient for miniaturized patterns
Solution Approach 1:
The patent replaces multi-step mechanical writing processes with a single writing operation enhanced by computational correction. The system performs position deviation calculations and applies deflection corrections during single writing, substituting the need for multiple writing passes with information-processing-based precision enhancement that maintains high accuracy while improving productivity.
Solution Approach 2:
The patent performs preliminary measurement of the substrate or reference patterns before writing, calculates expected position deviations in advance, and pre-adjusts deflection positions to compensate for anticipated errors. This preliminary correction action enables single writing to achieve high precision without requiring subsequent correction passes.
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 enhances deflection precision by correcting both position-dependent and time-dependent residual errors, ensuring accurate pattern formation on substrates with improved dimension accuracy, particularly in miniaturized semiconductor manufacturing.
Implementation Method 1
a charged particle source that emits a charged particle beam
Implementation Method 2
a deflector configured to deflect the charged particle beam from the charged particle source
Implementation Method 3
an objective lens configured to focus the charged particle beam from the deflector on a focal point
Data Source
AI summary
A charged particle beam writing apparatus includes an unit to measure height positions of a substrate, an unit to input a position dependent height distribution obtained by converting each position error of a pattern generated depending on each corresponding writing position of the substrate into a value in a height direction, and to add the position dependent height distribution to a height distribution obtained based on the height positions in order to correct the height distribution of the substrate, an unit to calculate a deflection shift amount of a pattern to be written by using a corrected height distribution, an unit to calculate a deflection amount for deflecting a beam to a position where a calculated deflection shift amount has been corrected, and an unit to write a pattern on the substrate by deflecting the beam by a calculated deflection amount.