Charged Particle Beam Writing Misregistration Correction
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Solution Overview
Problem
Current charged particle beam writing technologies face challenges in accurately aligning and correcting misregistration between substrates and their covers, leading to errors in pattern writing due to variations in mask shapes and diffraction conditions, which are not adequately addressed by existing methods.
Innovation Solution
A charged particle beam writing apparatus and method that utilizes a laser displacement meter to measure the position of the substrate and substrate cover, a correction unit to adjust for misregistration, and a substrate cover mounting/removal mechanism to ensure accurate alignment and positioning, allowing for precise pattern writing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a CCD camera is used to measure mask position, then an image of the mask can be captured, but illumination toward the camera across the mask is needed which causes diffraction conditions to change and measured results to vary
Solution Approach 1:
The patent replaces the optical measurement system (CCD camera with illumination) with a mechanical measurement system (laser displacement meter). The laser displacement meter measures the mask position by detecting the position of the mask's end face mechanically/optically without requiring illumination through the mask, thereby eliminating diffraction-related measurement variations and improving measurement reliability.
2Measurement precision
If a CCD camera with lighting system is used for mask alignment, then position can be found, but the measuring time is long due to operations to turn on and turn off the lighting system
Solution Approach 1:
The patent replaces the CCD camera-based optical measurement system with a laser displacement meter that uses a laser beam to directly measure the mask position. This eliminates the need for complex illumination systems that require turning on and off, significantly reducing measurement time while maintaining position detection capability.
3Manufacturing precision
If alignment of mask cover is performed by separately providing fulcrums for supporting and alignment, then misregistration between mask and mask cover can be reduced, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical fulcrum-based alignment system with a laser displacement meter-based measurement and correction system. The laser displacement meter measures the actual position of the mask cover, and a correction value is applied to the stage position to compensate for misregistration. This reduces the need for complex mechanical alignment mechanisms while improving alignment 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
This solution significantly reduces misregistration errors, achieving high accuracy in positioning and pattern writing by eliminating the need for illumination and minimizing measurement time, thereby improving the reliability of the charged particle beam writing process.
Implementation Method 1
a laser displacement meter to measure a position of a substrate to be written
Implementation Method 2
utilizes a laser displacement meter to measure the position of the substrate and substrate cover
Implementation Method 3
a writing unit to write a pattern onto the substrate corrected for the misregistration amount by using a charged particle beam
Data Source
AI summary
A charged particle beam writing apparatus according to an embodiment, includes a laser displacement meter configured to measure a position of a substrate to be written; a correction unit configured to correct a misregistration amount of the position of the substrate measured by the laser displacement meter from a reference position of the substrate; and a writing unit configured to write a pattern onto the substrate corrected for the misregistration amount by using a charged particle beam.