Colored Grating Structures Using DSA for Low-Defect Patterning
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Solution Overview
Problem
Conventional microelectronic fabrication techniques struggle to reliably pattern small features with low defects, particularly due to limitations in extreme ultraviolet (EUV) lithography, which face challenges in achieving both small feature sizes and low roughness while maintaining resist thickness for effective etch transfer.
Innovation Solution
Employing directed self-assembly (DSA) operations to utilize the self-organizing properties of materials, forming colored gratings with aligned conductive structures and spacers that mitigate edge placement errors and reduce bridging defects, enabling precise patterning of small features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional EUV lithography is used to pattern small features, then feature size is reduced, but roughness increases and bridging defects occur
Solution Approach 1:
The patent applies segmentation by dividing the patterning process into multiple stages: first forming a mandrel pattern, then using spacer deposition and removal cycles to subdivide the features further. This multi-step segmentation approach enables achieving smaller feature sizes with better precision than direct single-step lithography, effectively resolving the contradiction between feature size reduction and maintaining low roughness/defects.
2Manufacturing precision
If higher EUV dose is used to reduce roughness, then resist thickness must be reduced, but etch transfer capability deteriorates
Solution Approach 1:
The patent introduces an intermediary approach by using spacer materials as a mediating layer between the lithography process and the final pattern transfer. The spacers serve as a self-aligned mask that enables precise pattern definition without requiring high EUV doses, thereby maintaining both low roughness and adequate etch transfer capability through the spacer-mediated patterning process.
3Manufacturing precision
If directed self-assembly is used to form colored gratings, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by utilizing the inherent self-organizing properties of block copolymer materials in directed self-assembly. The materials automatically form ordered patterns with high precision alignment when provided with appropriate guidance structures, eliminating the need for complex external alignment systems. This self-service mechanism achieves high manufacturing precision while the modular nature of DSA actually reduces overall process complexity compared to conventional multi-step lithography alignment.
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
DSA-based techniques enable the fabrication of small and accurate microelectronic device features with reduced defects and improved reliability, overcoming the limitations of conventional EUV lithography.
Implementation Method 1
Employing directed self-assembly (DSA) operations to utilize the self-organizing properties of materials, forming colored gratings with aligned conductive structures and spacers
Data Source
Figure 1A~1C
Figure 2~4D
Figure 5A~6B
AI summary
Disclosed herein are colored gratings in microelectronic structures. For example, a microelectronic structure may include first conductive structures alternating with second conductive structures, wherein individual ones of the first conductive structures include a bottom portion and a top portion, individual cap structures are on individual ones of the second conductive structures, the bottom portions of the first conductive structures are laterally spaced apart from and aligned with the second conductive structures, and the top portions of the first conductive structures are laterally spaced apart from and aligned with the cap structures. In some embodiments, a microelectronic structure may include one or more unordered lamellar regions laterally spaced apart from and aligned with the first conductive structures.