SiOCN Adhesion Layer for Metal Oxide Resist in High-NA EUV Lithography
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Solution Overview
Problem
Current methods for forming fine patterns on substrates using metal oxide resist (MOR) face challenges such as metal contamination, critical dimension control, and defect control, particularly in high-numerical aperture extreme ultraviolet lithography, which require improved adhesion and etch selectivity.
Innovation Solution
A method involving a nonmetallic photoresist adhesion layer with tunable surface properties, formed using a cyclic deposition process, to promote adhesion between the carbon hard mask and MOR, and include nitrogen to enhance secondary electron emission, reducing radiation dose and improving pattern transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thin photoresist film is used for High-NA EUV lithography, then the resolution for smaller pitch patterns is improved, but line-edge and line-width roughness increase
Solution Approach 1:
An adhesion layer is introduced as an intermediary between the substrate and the thin photoresist film. This adhesion layer promotes uniform photoresist adhesion to the substrate, preventing pinholes and ensuring consistent film quality across the entire substrate surface, thereby reducing line-edge and line-width roughness while maintaining the benefits of thin film resolution
Solution Approach 2:
The composition and properties of the adhesion layer are optimized by adjusting parameters such as silicon oxide content (5-50 at%), carbon content (5-50 at%), and nitrogen content (5-50 at%). These parameter changes enable the adhesion layer to provide both strong substrate bonding and compatible surface properties for the photoresist, reducing roughness while preserving resolution
2Manufacturing precision
If metal oxide resist is used for High-NA EUV lithography, then resolution and local critical dimension uniformity are improved, but metal contamination control becomes more difficult
Solution Approach 1:
A nonmetallic adhesion layer is introduced as a barrier between the metal oxide resist and the substrate. This adhesion layer, composed of silicon oxide, carbon, and nitrogen, provides the necessary adhesion without introducing metal contamination, thereby maintaining the high resolution and dimensional uniformity benefits of metal oxide resist while preventing metal contamination
Solution Approach 2:
The adhesion layer acts as an inert barrier that prevents interaction between the metal oxide resist and the substrate environment. This protective layer blocks metal atoms from migrating to the photoresist, creating a contamination-free environment that preserves the quality of metal oxide resist patterns
3Manufacturing precision
If a carbon hard mask layer is used with metal oxide resist, then pattern transfer is improved, but adhesion between the mask and resist becomes insufficient
Solution Approach 1:
The adhesion layer serves as an intermediary between the carbon hard mask and the metal oxide resist. It provides a bonding interface that promotes strong adhesion between these two layers, preventing delamination and ensuring stable pattern transfer while maintaining the optical and etching properties of both the carbon mask and metal oxide resist
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 adhesion layer reduces metal contamination, enhances etch selectivity, and increases manufacturing throughput by minimizing defects and radiation exposure, making it suitable for high aspect ratio patterns and smaller feature sizes.
Implementation Method 1
use of a photoresist adhesion layer to promote adhesion between, for example, a carbon hard mask (CHM) and a MOR
Implementation Method 2
forming an adhesion layer using a (e.g., first) cyclic deposition process overlying the substrate surface
Implementation Method 3
the inclusion of nitrogen in the adhesion layer can increase a source of secondary electrons during a lithography process
Data Source
AI summary
Methods of forming structures including an adhesion layer and structures including the adhesion layer are disclosed. The adhesion layer may include nitrogen. The method can include forming a metal oxide resist overlying and in contact with the adhesion layer. Exemplary methods further include forming the photoresist underlayer.