Electron Beam Lithography Stitching With In-Situ Drift Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electron beam lithography systems face challenges in achieving high-precision stitching alignment due to mechanical movement errors and electron beam drift, leading to significant stitching errors and limited accuracy, especially in large-area pattern lithography, where traditional open-loop control systems cannot compensate for these errors in real-time.
Innovation Solution
A sub-nano-level high-precision lithography writing field stitching method using in-situ alignment coordinate marks and nano-contact sensors for real-time exposure deviation detection and closed-loop control, allowing for precise correction of electron beam exposure coordinates across multiple writing fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional open-loop control systems are used in electron beam lithography, then the system structure remains simple, but stitching alignment accuracy deteriorates due to inability to compensate for mechanical movement errors and electron beam drift in real-time
Solution Approach 1:
The patent implements a closed-loop control system that uses alignment marks and sensors to detect position deviations in real-time during wafer stage movement and electron beam scanning. The detected deviations are fed back to the control system, which automatically compensates for mechanical movement errors and electron beam drift by adjusting the beam position or stage movement, thereby achieving sub-nanometer stitching alignment accuracy without requiring extremely high-precision mechanical systems
Solution Approach 2:
The patent replaces reliance on high-precision mechanical positioning systems with a combination of alignment marks, optical/electrical sensing, and software-based closed-loop control. Instead of depending solely on mechanical precision, the system uses in-situ detection and computational correction to achieve high stitching accuracy, substituting mechanical complexity with sensor and control system intelligence
2Manufacturing precision
If high-precision electromechanical systems are used to achieve sub-nanometer stitching accuracy, then manufacturing precision improves, but production costs increase significantly
Solution Approach 1:
The patent replaces expensive high-precision electromechanical positioning systems with a more economical combination of standard-resolution sensors, alignment marks, and closed-loop control software. This substitution achieves the same sub-nanometer stitching accuracy at lower cost by using intelligent correction rather than purely mechanical precision
Solution Approach 2:
The system performs self-correction of positioning errors through in-situ detection of alignment marks and automatic feedback control. The lithography system monitors and compensates for its own mechanical and beam drift errors during operation, eliminating the need for external high-precision mechanical support systems and reducing overall system cost
3Area of stationary object
If multiple writing fields are exposed sequentially by moving the wafer workbench, then large-area pattern lithography becomes feasible, but stitching errors increase due to mechanical movement and electron beam drift
Solution Approach 1:
The patent places alignment marks at the boundaries between adjacent writing fields and uses sensors to detect their positions in real-time during sequential exposure. The detected position deviations are fed back to the control system, which compensates for cumulative stitching errors by adjusting subsequent writing field positions, enabling large-area lithography with maintained sub-nanometer precision across the entire area
Solution Approach 2:
The system performs preliminary detection and measurement of alignment mark positions before completing the exposure of each writing field. By detecting position deviations early in the sequential exposure process, the system can pre-calculate and apply correction values for subsequent writing fields, preventing error accumulation and maintaining high stitching accuracy across large areas
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 method enables seamless stitching of writing fields with sub-nanometer precision, reducing stitching errors and improving overall lithography accuracy without relying on high-precision electromechanical systems, thus lowering production costs and enhancing the capability of existing lithography systems.
Implementation Method 1
By scanning and exposing with the electron beam on the layer of the photosensitive resist layer based on a preset pattern, a chemical reaction is generated in the photosensitive resist layer
Implementation Method 2
each on the photosensitive resist layer the writing field is provided with a specific in-situ alignment coordinate mark that will show a predetermined shape after exposure
Data Source
AI summary
The invention discloses a sub-nanoscale high-precision lithography writing field stitching method. A photosensitive resist layer is coated on the surface of the wafer to be exposed; after the surface of the photosensitive resist layer is exposed, the exposed pattern will generate a tiny concave-convex structure; the concave-convex structure patterns are identified with a nano contact sensor and can be used as in-situ alignment coordinate markers; by comparing the position coordinates of the writing field before and after exposure and wafer moving, the deviations of stitching can be calculated, and an high-precision lithography stitching of the wafer is performed in a negative feedback control mode, so that the disadvantages of the existing non-in-situ, far-from-writing field and the poor performance of stitching precision in blind type open-loop lithography technology due to the influence of mechanical motion precision of a wafer workbench and long-time drift of an electron beam are overcome.