Variable Shaped Beam Lithography Shot Optimization
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Solution Overview
Problem
The existing methods for manufacturing reticles using variable shaped beam lithography are time-consuming and expensive due to the need for numerous non-overlapping simple shapes, which increases the complexity and cost of producing reticles with complex optical proximity correction features.
Innovation Solution
Allowing overlapping variable shaped beam shots with varying dosages to form patterns, using optimization techniques to minimize the shot count and utilizing pre-computed glyphs to reduce the number of shots required, while deviating from the desired pattern within a predetermined tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If non-overlapping simple shapes are used to manufacture reticles using variable shaped beam lithography, then manufacturing precision is maintained, but productivity decreases and manufacturing cost increases
Solution Approach 1:
The patent segments the reticle pattern into multiple simple shapes (rectangles, triangles, polygons) that can be formed by variable shaped beam lithography shots. These segmented shapes are then combined to create the final complex pattern, allowing the use of simple geometric primitives while achieving complex design outcomes.
Solution Approach 2:
The patent merges multiple VSB shots that overlap spatially to form the final pattern. By allowing shots to overlap and combining their effects, the method reduces the total number of shots required compared to using only non-overlapping simple shapes, thereby improving manufacturing productivity while maintaining pattern precision.
2Ease of manufacture
If non-overlapping simple shapes are used to manufacture reticles, then ease of manufacture is maintained, but loss of time increases
Solution Approach 1:
The patent performs preliminary computational optimization to determine the optimal set of VSB shots and their overlapping arrangements before manufacturing. This pre-computation of shot patterns and overlap configurations streamlines the actual manufacturing process, reducing the time required during production while maintaining ease of manufacture through automated shot generation.
3Manufacturing precision
If numerous shots are used to create complex optical proximity correction features, then manufacturing precision is improved, but device complexity increases and productivity decreases
Solution Approach 1:
The patent changes the parameters of the VSB shots, specifically allowing overlap between shots and varying shot dosages. This parameter modification enables the formation of complex optical proximity correction features with fewer shots, reducing device complexity while maintaining or improving manufacturing precision through optimized shot combinations.
4Manufacturing precision
If numerous shots are used to create complex optical proximity correction features, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent uses pre-computed shot patterns and glyph libraries that can be reused and copied for similar features in the reticle design. This copying approach reduces the computational and manufacturing time required for complex optical proximity correction features, improving productivity while maintaining pattern formation accuracy through proven shot configurations.
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 significantly reduces the time and expense of manufacturing reticles by enabling the creation of patterns with fewer shots, improving efficiency and reducing the computational complexity involved in particle beam simulation and shot optimization.
Implementation Method 1
maskless direct write is a printing process in which charged particle beam lithography is used to transfer patterns to a substrate such as a semiconductor or silicon wafer
Implementation Method 2
optical lithography is a printing process in which a lithographic mask manufactured from a reticle is used to transfer patterns to a substrate such as a semiconductor or silicon wafer
Data Source
Figure 1
Figure 2
Figure 3A~4C
AI summary
The present invention describes a method for using variable shaped beam (VSB) shots to form a desired pattern on a surface, where the union of the plurality of VSB shots deviates from the desired pattern. Additionally, the VSB shots are allowed to overlap each other, and the dosages of the shots are allowed to vary. Similar methods are disclosed for optical proximity correction (OPC), fracturing, mask data preparation, and proximity effect correction. A method for creating glyphs is also disclosed, in which patterns that would result on a surface from one or a group of VSB shots are pre-calculated. In some embodiments, an optimization technique may be used to minimize shot count. The method of the present disclosure may be used, for example, in the process of manufacturing an integrated circuit by optical lithography using a reticle, or in the process of manufacturing an integrated circuit using direct write.