Composite Multiple-Patterning Mask for Overlay Control
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Solution Overview
Problem
Current photolithographic techniques face challenges in achieving accurate feature formation and increased complexity as device size decreases, leading to overlay issues and increased costs with multiple-patterning processes, which affect yield and throughput in IC manufacturing.
Innovation Solution
The use of a composite multiple-patterning mask with sub-reticles allows for improved overlay control and reduced costs by eliminating inter-mask variations, reducing the number of masks needed, and minimizing alignment and exposure time, thereby enhancing yield and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple separate masks are used for patterning, then feature size can be reduced, but overlay errors and alignment time increase
Solution Approach 1:
The patent combines multiple sub-reticles containing different pattern sets onto a single mask substrate, creating a composite mask. This merging eliminates the need for multiple separate mask alignment operations, thereby reducing alignment time and overlay errors while maintaining the ability to form small features through multiple patterning sequences.
Solution Approach 2:
The mask is segmented into multiple sub-reticles, each containing specific pattern sets for different exposure sequences. This segmentation allows the single mask to deliver multiple pattern sets through different orientations and exposures, enabling reduced feature sizes without requiring multiple physical masks.
2Manufacturing precision
If multiple separate masks are used for patterning, then feature size can be reduced, but manufacturing complexity and costs increase
Solution Approach 1:
The patent merges multiple pattern sets that would traditionally require separate masks into a single composite mask with multiple sub-reticles. This reduces the total number of masks needed in the manufacturing process, simplifying inventory management, mask handling, and overall process complexity while maintaining the capability to form small features.
3Manufacturing precision
If multiple separate masks are used for patterning, then feature size can be reduced, but yield decreases due to overlay errors
Solution Approach 1:
By combining all required pattern sets into a single composite mask, the invention eliminates inter-mask overlay errors that occur when multiple separate masks are used. The single mask ensures consistent alignment reference across all pattern sets, improving yield while maintaining the ability to form small features through multiple exposure sequences.
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 composite multiple-patterning mask improves yield and reduces costs by minimizing overlay errors, alignment time, and mask-related expenses, while maintaining the advantages of multiple-patterning processes such as smaller feature sizes and increased circuit reliability.
Implementation Method 1
performing a first photolithographic process including exposing the substrate using the mask to form a first exposed area on the substrate
Data Source
AI summary
A composite mask suitable for multiple-patterning lithographic processes and a multiple-patterning photolithographic process utilizing the mask are disclosed. An exemplary embodiment includes receiving a mask having a plurality of sub-reticles and a substrate having one or more regions. A first sub-reticle of the plurality of sub-reticles is aligned with a first region of the one or more regions. A movement pattern is designated relative to the substrate. A first photolithographic process is performed including exposing the substrate using the mask to form a first exposed area on the substrate. An alignment of the mask relative to the substrate is shifted according to a first direction determined by the movement pattern. A second photolithographic process is performed including exposing the substrate using the mask to form a second exposed area on the substrate such that the second exposed area overlaps the first.