Lithography Probe Modulation for Sub-Pixel Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithography systems face challenges in accurately positioning pattern features on a substrate due to limitations in grid size and the need for complex and costly blanker structures, leading to inefficiencies and inaccuracies, especially in multi-beam systems where proximity effects and throughput are critical.
Innovation Solution
The system employs a virtual grid with a point spread function larger than the grid cell size, allowing for sub-pixel positioning of features and edges by modulating multiple grid cells and adjusting the dose, enabling precise and smooth edge placement without increasing data processing or requiring complex blanker structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the grid size is reduced to improve positioning accuracy, then manufacturing precision is improved, but device complexity increases due to the need for complex and costly blanker structures capable of swift switching
Solution Approach 1:
The patent segments the writing process into multiple passes, where each pass writes a portion of the pattern. This allows the use of a larger grid size with simpler blanker structures while achieving high positioning accuracy through cumulative writing. The pattern is divided into sub-regions that are written sequentially, eliminating the need for complex fast-switching blankers required by fine-grid single-pass systems.
Solution Approach 2:
The patent performs preliminary positioning calculations and pattern division before the actual writing process. The control unit pre-calculates the multi-pass writing strategy, determining which grid cells to write in each pass. This preliminary planning enables the system to achieve high precision without requiring complex real-time switching mechanisms during writing.
2Manufacturing precision
If the grid size is reduced to improve positioning accuracy, then manufacturing precision is improved, but data processing load increases
Solution Approach 1:
The patent segments both the physical writing process and the data processing workload across multiple passes. Each pass processes a subset of grid cells, reducing the data processing load per pass while maintaining overall positioning accuracy. The control unit manages the segmented data flow, processing only the necessary subset of pattern data for each pass rather than handling the entire pattern at once.
3Productivity
If multiple writing beams are used to increase throughput, then productivity is improved, but positioning accuracy deteriorates due to proximity effects and coordination challenges
Solution Approach 1:
The patent segments the pattern assignment among multiple writing beams, with each beam responsible for specific sub-regions or feature types. This segmentation reduces proximity effects between beams by spatially separating their writing zones. The control unit coordinates the segmented writing tasks, ensuring that each beam writes its assigned portion with high precision while maintaining overall pattern integrity.
Solution Approach 2:
The patent applies local quality control by assigning different writing parameters and strategies to different writing beams based on their specific tasks. Each beam can be optimized for its local writing requirements, with the control unit adjusting parameters such as writing speed, probe positioning, and pass sequences individually for each beam. This localized optimization maintains high positioning accuracy across all beams while maximizing overall throughput.
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 achieves highly accurate and smooth feature placement with reduced sensitivity to inaccuracy, maintaining throughput and avoiding the need for complex blanker systems, while allowing for refined control of feature size and position, even in massive multi-beam systems.
Implementation Method 1
the probe effect in the target surface, which in turn is often described by a so-called point spread function. The point spread function (PSF) generally has a Gaussian distribution.
Data Source
AI summary
The present invention relates a probe forming lithography system for generating a pattern on to a target surface such as a wafer, using a black and white writing strategy, i.e. writing or not writing a grid cell, thereby dividing said pattern over a grid comprising grid cells, said pattern comprising features of a size larger than that of a grid cell, in each of which cells said probe is switched “on” or “off, wherein a probe on said target covers a significantly larger surface area than a grid cell, and wherein within a feature a position dependent distribution of black and white writings is effected within the range of the probe size as well as to a method upon which such system may be based.