Metal Sidewall Spacers for Sub-20 Nm EUV Patterning
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Solution Overview
Problem
Conventional extreme ultraviolet (EUV) lithography scanners face resolution limits in printing critical dimensions below 20 nm for isolated structure patterns such as contacts and holes for vias, and Metal Organic Resists (MOR) and Chemically Amplified Resists (CAR) counterparts suffer from similar EUV resolution limitations.
Innovation Solution
A method involving forming a patterned resist with a first metal, partially exposing it, and creating a liner on the sidewalls using a second metal, followed by etching to form spacers, which allows for reducing critical dimensions below 20 nm by employing materials like Sn, In, Sb, Ti, Al, Zn, Hf, and Zr, with similar or identical etch rates to the resist.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional EUV lithography scanners are used, then the manufacturing process is simple, but the critical dimension resolution is limited to about 20 nm for isolated structures
Solution Approach 1:
The patterning process is divided into multiple steps: forming initial patterned resist features, depositing a liner material on sidewalls, and using the liner as a template for final pattern formation. This segmentation allows each step to be optimized independently, achieving sub-20 nm resolution that cannot be obtained through single-step lithography
Solution Approach 2:
The liner is formed on the sidewalls of the patterned resist features before the final pattern transfer. This preliminary action creates a template structure that defines the final critical dimensions, enabling precise control of feature sizes below 20 nm that would be unattainable with conventional direct lithography
2Manufacturing precision
If thinner photoresist layers are used to achieve smaller critical dimensions, then the pattern transfer becomes easier with less defectivity, but the EUV resolution limitation remains at about 20 nm
Solution Approach 1:
The liner material acts as an intermediary between the patterned resist and the final pattern transfer. The liner is deposited on the sidewalls of the resist features and serves as a template that defines the final critical dimensions. This intermediary structure enables sub-20 nm resolution by decoupling the lithography step from the final pattern definition, allowing the resist thickness to be optimized for etch resistance while the liner thickness controls the final CD
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
Enables efficient formation of patterns with critical dimensions less than 20 nm, improving feature uniformity, reducing defects, and lowering costs through the use of spacers formed directly after lithography, with enhanced throughput and low roughness.
Implementation Method 1
partially exposing the substrate to radiation through a mask. Accordingly, exposed resist portions and unexposed resist portions are formed
Implementation Method 2
forming a liner on the sidewalls. The liner comprises a second metal
Implementation Method 3
the step of forming the liner is further followed by etching the liner. Thus, the liner is removed from the patterned features and the bottom portions of the recesses, and forming spacers on the sidewalls
Data Source
AI summary
Methods for patterning and forming structures, as well as related structures and systems are disclosed. The methods comprise forming a liner on sidewalls of a patterned resist. The patterned resist comprises a first metal, and the liner comprises a second metal.