VSB Reticle Fracturing for Curvilinear Mask Pattern Precision
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Solution Overview
Problem
Current reticle enhancement technologies face challenges in achieving precise and resilient mask patterns for semiconductor lithography, particularly in handling curvilinear shapes and managing computational demands, which results in increased costs and complexity due to the need for extensive computation and laborious OPC feature addition.
Innovation Solution
The implementation of Mask Wafer Co-optimization (MWCO) techniques that combine inverse lithography technology (ILT) for mask manufacturability and model-based Mask Data Preparation (MDP) for wafer quality optimization, reducing the number of shots required and improving process window resilience without substantial increases in compute time or runtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional OPC techniques are used to enhance mask patterns, then manufacturing precision is improved, but device complexity and computational demands increase significantly
Solution Approach 1:
The patent extracts and removes OPC features from the mask pattern after they have served their purpose of enhancing manufacturing precision during lithography. This extraction eliminates the complexity burden of OPC features while preserving the precision benefits they provided during the critical manufacturing phase.
Solution Approach 2:
The patent applies OPC techniques in advance during the mask design phase to pre-enhance pattern precision. By performing OPC computations beforehand and then removing the added features, the system achieves precision improvement without carrying the ongoing complexity burden through subsequent manufacturing stages.
2Manufacturing precision
If extensive OPC computation is performed to achieve precise mask patterns, then manufacturing precision is improved, but loss of time increases due to laborious computation
Solution Approach 1:
The patent removes OPC features after they have fulfilled their precision-enhancing function during lithography exposure. This extraction allows the system to achieve high manufacturing precision through comprehensive OPC computation while minimizing the time burden by eliminating the need to process and manage complex OPC features through subsequent manufacturing stages.
Solution Approach 2:
The patent performs all necessary OPC computations in advance during mask design, then removes the added complexity. This preliminary action concentrates the computational time burden to a specific phase rather than distributing it throughout the entire manufacturing process, improving overall efficiency while maintaining precision.
3Manufacturing precision
If curvilinear shapes are handled with conventional methods, then manufacturing precision is maintained, but device complexity increases due to extensive computation requirements
Solution Approach 1:
The patent extracts OPC features from curvilinear shape patterns after they have enhanced manufacturing precision during lithography. This approach allows complex curvilinear shapes to be rendered with high precision through OPC while removing the computational complexity burden that would otherwise persist through subsequent manufacturing stages.
Solution Approach 2:
The patent applies OPC computations to curvilinear shapes in advance during mask design, then removes the added OPC features. This preliminary action enables high-precision curvilinear pattern formation while concentrating the computational complexity to a specific design phase rather than requiring ongoing complex computations throughout manufacturing.
Data Source
AI summary
Methods for fracturing a pattern to be exposed on a surface using variable shaped beam (VSB) lithography include inputting an initial pattern; calculating a first substrate pattern from the initial pattern; overlaying the initial pattern with a two-dimensional grid, wherein an initial set of VSB shots are formed by a union of the initial pattern with locations on the grid; and merging two or more adjacent shots in the initial set of VSB shots to create a larger shot in a modified set of VSB shots; and outputting the modified set of VSB shots. The method also includes calculating a calculated pattern to be exposed on the surface with the modified set of VSB shots; and calculating a second substrate pattern from the calculated pattern to be exposed on the surface.