Lithography Edge Contrast via Pixel Dosage Redistribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithography systems, particularly charged particle beam lithography, face challenges in achieving enhanced image contrast due to scattering behavior, which results in poor image contrast and resolution issues when forming patterns on wafers, especially at the edge portions of IC features.
Innovation Solution
A charged particle beam lithography system and method that adjusts the exposure dosage by 'robbing' energy from dark pixels and directing it to bright edge pixels, allowing for increased exposure at edge portions without reducing throughput, achieved through a single pass raster scanning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If charged particle beam lithography is used to form IC features smaller than light resolution, then manufacturing precision is improved, but image contrast deteriorates due to scattering behavior
Solution Approach 1:
The patent applies local quality by differentiating exposure dosage based on spatial location within the pattern. Edge portions of IC features receive enhanced exposure dosage compared to interior portions, creating a non-uniform exposure distribution that compensates for scattering effects. This is achieved through algorithms that identify edge pixels and assign them higher dosage values, thereby improving image contrast specifically at critical edge regions without over-exposing interior regions.
Solution Approach 2:
The patent changes the exposure dosage parameter dynamically based on the spatial position and pattern geometry. By adjusting the exposure dosage parameter for different regions (higher at edges, lower in interiors), the system optimizes both manufacturing precision and image contrast. This parameter modification approach allows the lithography process to adapt to the varying requirements different parts of the pattern impose.
2Manufacturing precision
If exposure dosage is increased at edge portions to improve image contrast, then manufacturing precision is improved, but processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating the optimal exposure dosage distribution across the entire pattern before the actual lithography exposure. Algorithms analyze the IC design layout, identify all edge portions, and compute the required dosage adjustments in advance. This preprocessing step creates an optimized exposure map that guides the lithography system, allowing the actual exposure to proceed efficiently without real-time calculations that would slow down processing.
Solution Approach 2:
The patent introduces dynamics by implementing a variable exposure dosage strategy that adapts to different pattern regions. Rather than using a static uniform dosage, the system dynamically adjusts exposure parameters based on the local pattern geometry, particularly distinguishing between edge and interior regions. This dynamic approach allows optimized contrast enhancement at edges while maintaining efficient processing across the entire wafer surface.
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 image contrast and resolution by increasing exposure dosage at edge portions of IC patterns, improving the fidelity of the final wafer patterns without compromising the processing time or efficiency of the lithography system.
Implementation Method 1
charged particle beam lithography, which involves writing an IC pattern on a workpiece using a charged particle beam without a mask
Implementation Method 2
scattering behavior of the charged particle beam as it scans the workpiece limits often results in final wafer patterns having poor image contrast
Data Source
AI summary
Systems and methods are disclosed herein for enhancing lithography printability, and in particular, for enhancing image contrast. An exemplary method includes receiving an integrated circuit (IC) design layout and generating an exposure map based on the IC design layout. The IC design layout includes a target pattern to be formed on a workpiece, and the exposure map includes an exposure grid divided into dark pixels and bright pixels that combine to form the target pattern. The method further includes adjusting the exposure map to increase exposure dosage at edges of the target pattern. In some implementations, the adjusting includes locating an edge portion of the target pattern in the exposure map, where the edge portion has a corresponding bright pixel, and assigning exposure energy from at least one dark pixel to the corresponding bright pixel, thereby generating a modified exposure map.