Multi-Transmission Rate Optical Mask for Lithography
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Solution Overview
Problem
The existing methods for manufacturing semiconductor devices face challenges in achieving high circuit density and complexity due to limitations in mask set procurement, which are expensive and time-consuming, and there is a need for improved techniques to efficiently produce custom integrated circuits with smaller device features.
Innovation Solution
A multi-transmission rate optical mask structure is introduced, comprising a quartz substrate with regions of binary and attenuated phase shift mask patterns, allowing for different optical characteristics and enabling the use of a single light source and mask structure to create various pattern sizes, thereby enhancing device yields and process compatibility with conventional technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If custom mask sets are procured for each integrated circuit design, then manufacturing precision is improved, but loss of time and manufacturing cost increase significantly
Solution Approach 1:
The patent creates a universal mask set that can be used across multiple integrated circuit designs and generations. By establishing standard library cells and modular mask structures, the same physical mask can serve multiple purposes and be reused for different circuit configurations, eliminating the need for custom mask fabrication for each design while maintaining manufacturing precision
Solution Approach 2:
The mask set is divided into standardized library cells and modular components that can be independently designed and reused. This segmentation allows different circuit designs to be constructed by combining standardized mask elements, reducing the need for complete custom mask sets while preserving the ability to achieve precise pattern fabrication
2Productivity
If device geometry is reduced to increase circuit density, then productivity is improved, but manufacturing precision becomes more difficult to achieve
Solution Approach 1:
The patent employs parameter changes in the mask design, including varying transmission rates (binary, attenuated phase shift with different attenuation percentages) and dimensional adjustments in mask features. These parameter variations allow optimization of the lithographic process for different device geometries, enabling precise control of smaller features while maintaining high circuit density
Solution Approach 2:
Different regions of the mask are assigned different optical properties (binary regions, attenuated phase shift regions with varying attenuation levels) to optimize pattern formation for specific feature sizes and densities. This local differentiation allows the same mask to produce high-precision patterns across varying device geometries and circuit density requirements
3Device complexity
If conventional mask sets are used for multiple pattern sizes, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The mask set is designed with multi-functionality to produce multiple pattern sizes and geometries using a single physical mask. By incorporating standardized library cells and modular structures with varying transmission characteristics, the same mask can generate different pattern resolutions and device complexities without requiring multiple specialized mask sets
Solution Approach 2:
The mask incorporates regions with different transmission parameters (binary, attenuated phase shift at various attenuation levels) that can be selectively used to produce different pattern sizes and resolutions. This parameter diversity within a single mask structure allows maintenance of manufacturing precision across varying device complexities
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
The multi-transmission rate optical mask structure improves device yields, provides better resolution and depth of focus, and allows for the production of different pattern sizes using conventional technology without substantial equipment modifications, addressing the limitations of conventional mask sets.
Implementation Method 1
A second region comprising a plurality of first attenuated phase shift mask patterns is formed on a second portion of the surface region. A third region comprising a plurality of second attenuated phase shift mask patterns is formed on a third portion of the surface region
Implementation Method 2
The multi-transmission rate optical mask structure improves device yields, provides better resolution and depth of focus
Data Source
AI summary
A reticle device. The device has a quartz substrate, which has a surface region. A first region comprising a plurality of binary mask patterns is formed on a first portion of the surface region. A second region comprising a plurality of first phase shift mask patterns is formed on a second portion of the surface region. A third region comprising a plurality of second phase shift mask patterns is formed on a third portion of the surface region. Accordingly, the reticle device has at least three different regions corresponding to different optical characteristics.