Mask Reticle Boundary Overlay Mark Arrangement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing mask reticle designs have a large boundary area that restricts the number of exposure pattern areas and the integration density, limiting the precision and efficiency of chip production due to the fixed arrangement of overlay marks.
Innovation Solution
A mask reticle design with a first boundary area and multiple exposure pattern areas, where the boundary area includes symmetrically arranged overlay mark units with overlay marks aligned along transversal or longitudinal lines, allowing for reduced boundary width and increased exposure pattern area utilization by displacing overlay marks, thereby reducing the distance between exposure fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the boundary area is reduced to increase the number of exposure pattern areas, then the productivity and utilization ratio improve, but the arrangement of overlay marks becomes more difficult and overlay precision may deteriorate
Solution Approach 1:
The overlay mark units are segmented into multiple individual overlay marks within each unit. Each overlay mark unit contains multiple overlay marks that can be independently arranged, allowing the boundary area to be efficiently utilized while maintaining sufficient overlay marks for precision alignment. This segmentation enables the system to fit more overlay marks into the reduced boundary area without compromising overlay precision.
Solution Approach 2:
The overlay marks are arranged not only in one dimension but in two dimensions within the boundary area. The first boundary lines extend in a first direction and the second boundary lines extend in a second direction perpendicular to the first direction, creating a grid-like structure that maximizes the utilization of the boundary area. This two-dimensional arrangement allows more overlay marks to be packed into the reduced boundary area while maintaining proper spacing for precision.
2Quantity of substance
If the boundary area dimension is reduced, then the number of exposure pattern areas increases, but the area ratio of boundary area increases
Solution Approach 1:
The boundary area is designed with non-uniform characteristics where different regions serve different functions. The first boundary area contains the first overlay mark units with specific arrangement patterns, while the second boundary area contains the second overlay mark units. This local differentiation allows each region to be optimized for its specific purpose, maximizing the information density and functionality within the reduced overall boundary area.
Solution Approach 2:
Multiple overlay mark units are merged into a compact arrangement within the reduced boundary area. The first and second overlay mark units are positioned adjacent to each other, sharing common boundary lines and space. This merging reduces the total area required for boundary structures while maintaining the functionality of multiple overlay mark units for precise alignment across different exposure fields.
3Manufacturing precision
If overlay marks are displaced to reduce distance between exposure fields, then the integration density improves, but the arrangement complexity increases
Solution Approach 1:
The overlay marks within each overlay mark unit are arranged asymmetrically rather than in a simple symmetric pattern. The multiple overlay marks are positioned at different locations and orientations within the boundary area, with some marks closer to certain exposure fields than others. This asymmetric arrangement optimizes the displacement relationships between adjacent exposure fields, enabling reduced distance between fields while maintaining precise alignment capabilities.
Solution Approach 2:
The arrangement of overlay marks provides dynamic adjustment capabilities for the displacement between exposure fields. By having multiple overlay marks at different positions and orientations within each overlay mark unit, the system can accommodate various displacement vectors and magnitudes between adjacent exposure fields. This dynamic arrangement flexibility allows optimization of the distance between exposure fields while maintaining alignment precision across different field pairs.
Data Source
AI summary
A mask includes a first boundary area and a plurality of exposure pattern areas, the first boundary area including a region surrounding the plurality of exposure pattern areas; in the first boundary area is disposed a plurality of first overlay mark units, each of which includes a plurality of overlay marks; the plurality of overlay marks are sequentially arranged along extension directions of adjacent transversal or longitudinal first boundary lines; a plurality of first overlay mark units are symmetric in pairs with a central line of the mask as a symmetric axis, and two symmetric first overlay mark units form an overlay mark set; arrangement directions of two overlay marks in the first overlay mark units in the same overlay mark set are parallel to and displaced with respect to each other.