Charged Particle Beam Lithography Shot Overlap Control
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Solution Overview
Problem
Charged particle beam lithography faces challenges in reducing sensitivity to beam blur (βf) variations, which affect the accuracy and precision of pattern formation on reticles and wafers, particularly as feature sizes approach sub-100 nm dimensions, leading to increased manufacturing variations and complexity in OPC features.
Innovation Solution
The method involves determining a plurality of shots that overlap to reduce sensitivity to βf variations, either during initial shot determination or in a post-processing step, allowing for expanded process windows and improved pattern accuracy by controlling shot overlap and dosage distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional charged particle beam lithography is used with non-overlapping shots, then the manufacturing process is simpler and faster, but the pattern formation becomes highly sensitive to beam blur (βf) variations, reducing manufacturing precision
Solution Approach 1:
The method performs preliminary determination of overlapping shots and their dosages before actual pattern formation. By pre-calculating the shot configuration that accounts for beam blur effects, the system establishes a robust exposure plan that compensates for βf variations before the lithography process begins, thereby improving pattern accuracy without adding complexity during manufacturing
Solution Approach 2:
The invention changes the parameters of shot overlap and dosage distribution to optimize pattern formation. By adjusting these parameters, the method reduces sensitivity to beam blur variations while maintaining manufacturing simplicity, effectively resolving the contradiction between precision and complexity
2Manufacturing precision
If feature sizes are reduced to sub-100 nm dimensions, then higher resolution patterns are achieved, but sensitivity to beam blur (βf) variations increases, worsening manufacturing precision
Solution Approach 1:
The method optimizes shot overlap parameters and dosage distributions specifically tailored for sub-100 nm feature sizes. By adjusting these parameters, the system compensates for increased beam blur sensitivity at smaller dimensions, maintaining pattern accuracy despite the harmful effects of βf variations
Solution Approach 2:
The invention incorporates feedback mechanisms that account for beam blur effects in the shot determination process. By using information about βf variations to adjust shot configuration and dosage, the system actively compensates for the harmful effects of beam blur on sub-100 nm pattern formation
3Manufacturing precision
If complex OPC features are added to compensate for beam blur effects, then pattern accuracy is improved, but device complexity and manufacturing complexity increase
Solution Approach 1:
Instead of adding complex OPC features as a separate corrective step, the method performs preliminary optimization of shot configuration and dosage that inherently accounts for beam blur effects. This preliminary action achieves pattern accuracy compensation without requiring additional complex OPC features, thereby avoiding increased device and manufacturing complexity
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 results in higher quality patterns with reduced sensitivity to βf variations, enabling more accurate and precise pattern formation on reticles and wafers, even at advanced technology nodes, and reduces the need for complex OPC features.
Implementation Method 1
charged particle beam lithography is used to transfer patterns to a substrate
Implementation Method 2
sensitivity to changes in βf (beam blur)
Data Source
AI summary
In a method for fracturing or mask data preparation or mask process correction for charged particle beam lithography, a plurality of shots are determined that will form a pattern on a surface, where shots are determined so as to reduce sensitivity of the resulting pattern to changes in beam blur (βf). At least some shots in the plurality of shots overlap other shots. In some embodiments, βf is reduced by controlling the amount of shot overlap in the plurality of shots, either during initial shot determination, or in a post-processing step. The reduced sensitivity to βf expands the process window for the charged particle beam lithography process.