Charged Particle Beam Writing Apparatus Distortion Correction
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Solution Overview
Problem
Current charged particle beam writing techniques face challenges in accurately correcting global position errors due to distortion and flexure in the electron optical system and mask surfaces, leading to insufficient precision in pattern formation, especially with the miniaturization of semiconductor devices.
Innovation Solution
A charged particle beam writing apparatus and method that utilize a dummy target workpiece to measure and correct global position errors by adjusting the reference position and relative distance using correction equations, incorporating a main deflector and sub deflector to precisely align and write patterns on the target workpiece, accounting for distortion and flexure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional distortion correction methods are used that only correct reference positions of subfields, then the correction process is simple, but global position errors and distortion within subfields remain uncorrected
Solution Approach 1:
The correction system is segmented into two independent correction units: a first correction unit that corrects reference positions of subfields, and a second correction unit that corrects relative distances within subfields. This segmentation allows each unit to focus on specific correction tasks, improving overall precision without requiring a completely complex redesign of the entire correction system.
Solution Approach 2:
The first correction unit performs preliminary correction of reference positions before the second correction unit adjusts relative distances within subfields. This sequential preliminary action ensures that corrections are applied in a systematic manner, addressing global position errors first and then local distortion, thereby improving manufacturing precision through staged correction.
2Manufacturing precision
If only reference positions of subfields are corrected, then the correction process is fast and simple, but distortion within subfields cannot be corrected
Solution Approach 1:
The correction process is divided into two segmented stages: reference position correction and relative distance correction. This segmentation allows the system to address different types of errors (global position errors and local distortion) separately, ensuring that subfield distortion is corrected without requiring a complete redesign that would significantly increase correction time.
Solution Approach 2:
The first correction unit performs preliminary correction of reference positions, and then the second correction unit performs relative distance correction within subfields. This preliminary action approach ensures that time-consuming corrections are performed in a systematic sequence, addressing distortion while minimizing overall correction time through efficient staged processing.
3Manufacturing precision
If correction equations are applied to both reference positions and relative distances, then comprehensive distortion correction is achieved, but the calculation complexity increases
Solution Approach 1:
The correction calculation is segmented into two independent sets of equations: one for reference position correction and another for relative distance correction. This segmentation reduces calculation complexity by breaking down the comprehensive correction task into manageable parts, while still achieving thorough distortion correction through the combination of both correction sets.
Solution Approach 2:
Correction equations are applied in a preliminary sequence: first to reference positions, then to relative distances within subfields. This preliminary action approach ensures that complex calculations are performed in a systematic order, reducing overall computational burden while achieving comprehensive distortion correction through staged mathematical processing.
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 enables highly accurate correction of global position errors and distortion, enhancing the precision of pattern writing and addressing the limitations of existing methods by using a combination of main and sub deflection corrections.
Implementation Method 1
a charged particle beam writing apparatus includes a main deflector configured to deflect the charged particle beam, based on a corrected reference position, and a sub deflector configured to further deflect the charged particle beam
Data Source
AI summary
A charged particle beam writing apparatus includes a unit emitting a charged particle beam, a stage on which a target workpiece to be written is placed, a unit correcting a reference position of a small region in a writing region, based on a pattern distortion obtained from positions of figures spread over substantially all writing region of a dummy target workpiece and written without correcting, a first deflector deflecting the beam, based on a corrected reference position obtained by correcting the reference position, a correction unit correcting a relative distance from the corrected reference position to an arbitrary position in the small region, based on a pattern distortion of the dummy, by using the reference position and a coefficient of a correction equation for correcting the reference position, and a second deflector further deflecting the beam from a position deflected by the first deflector, based on the relative distance corrected.