Multi-Layer Hardmask Structure for Defect-Reduced EUV Patterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional EUV lithography techniques face challenges in transferring patterns to underlying hardmask films due to resist scumming and local thinning, leading to microbridges and line breaks, especially at sub-30 nm pitch, resulting in high defects and low yield.
Innovation Solution
A multi-layer hardmask is introduced, comprising a lower layer of inorganic dielectric silicon-containing material and an upper layer of metal oxide, metal nitride, or metal oxynitride, which provides improved selectivity and reduces resist scumming by enabling secondary electron generation during EUV exposure, allowing for faithful pattern transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional EUV lithography techniques are used for patterning, then the process is simple, but resist scumming and local thinning occur leading to microbridges and line breaks
Solution Approach 1:
The hardmask is divided into multiple layers (e.g., silicon-containing inorganic dielectric lower layer and metal oxide upper layer) to provide different functions: the lower layer provides adhesion and structural support, while the upper layer enables secondary electron generation during EUV exposure. This segmentation resolves the contradiction by maintaining process simplicity while improving pattern transfer quality through specialized layer functions.
Solution Approach 2:
The patent uses composite material structures combining silicon-containing inorganic dielectric materials with metal oxides, metal nitrides, or metal oxynitrides. This composite approach enables both the adhesion properties needed to prevent line breaks and the secondary electron generation capability needed to prevent resist scumming, thereby improving manufacturing precision without complicating the overall process.
2Device complexity
If a single-layer hardmask is used, then the structure is simple, but selectivity and adhesion are insufficient leading to high defects
Solution Approach 1:
The hardmask is segmented into multiple layers with distinct material compositions and functions. The lower layer (silicon-containing inorganic dielectric) provides adhesion to the underlying substrate, while the upper layer (metal oxide, nitride, or oxynitride) provides high selectivity during etching and enables secondary electron generation. This segmentation improves reliability by ensuring each layer performs its specific function optimally.
Solution Approach 2:
Different regions of the hardmask structure are assigned different material properties: the lower layer has high adhesion quality for bonding to the substrate, while the upper layer has high etch selectivity and secondary electron generation capability. This local quality differentiation resolves the contradiction between structural simplicity and pattern transfer reliability.
3Strength
If additional adhesion layers are added to improve adhesion, then adhesion is improved, but the process complexity increases
Solution Approach 1:
The silicon-containing inorganic dielectric lower layer of the hardmask serves multiple functions simultaneously: it provides strong adhesion to the underlying substrate, acts as a structural support layer, and contributes to the overall etch selectivity. By making this layer multi-functional, the patent eliminates the need for separate dedicated adhesion layers, thereby improving adhesion strength without increasing process complexity.
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-layer hardmask significantly reduces microbridges and defects, enhancing pattern transfer quality and yield by providing high selectivity and adhesion without the need for additional adhesion layers, thus improving the EUV lithography process.
Implementation Method 1
enabling secondary electron generation during EUV exposure
Data Source
AI summary
Various embodiments herein relate to methods, apparatus, and systems that utilize a multi-layer hardmask in the context of patterning a semiconductor substrate using extreme ultraviolet photoresist. The multi-layer hardmask includes (1) an upper layer that includes a metal-containing material such as a metal oxide, a metal nitride, or a metal oxynitride, and (2) a lower layer that includes an inorganic dielectric silicon-containing material. Together, these layers of the multi-layer hardmask provide excellent etch selectivity and reduce formation of defects such as microbridges and line breaks. Certain embodiments relate to deposition of the multi-layer hardmask. Other embodiments relate to etching of the multi-layer hardmask. Some embodiments involve both deposition and etching of the multi-layer hardmask.