Ultra-Thin Surface-Modified Layer for Photoresist Adhesion
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Solution Overview
Problem
Existing resist underlayer films face issues with etching defects such as side etching during the etching step, and it is challenging to uniformly form a thin surface-modified layer that improves photoresist adhesion and resolution without causing these defects.
Innovation Solution
A method involving the application of a surface modifier containing a polymer and a solvent to a semiconductor substrate, followed by baking to form a surface-modified layer precursor, and then thinning it with a thinning liquid to achieve a film thickness of 5 nm or less, using polysiloxane with specific functional groups and ionic bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a known resist underlayer film is used, then adhesion with photoresist is improved, but etching defects such as side etching occur
Solution Approach 1:
The invention changes the film thickness parameter from conventional thicker underlayer films to an ultra-thin film of 5 nm or less. This parameter change allows the film to provide sufficient adhesion for photoresist while being too thin to cause etching defects during the etching process, thus resolving the contradiction between adhesion strength and etching defect prevention
Solution Approach 2:
The invention applies a surface-modified layer with specific local properties (ultra-thin thickness of 5 nm or less, cross-linked polymer structure) only where needed on the semiconductor substrate. This localized application provides adhesion enhancement precisely at the interface with photoresist without extending into regions where it would cause etching defects
2Manufacturing precision
If a thin surface-modified layer is formed to improve photoresist adhesion and resolution, then lithography performance is improved, but uniform formation of the thin layer becomes difficult
Solution Approach 1:
The invention applies a surface modifier containing a polymer and solvent to the substrate, then performs a baking step before the thinning step. This preliminary action of forming a cross-linked polymer layer first ensures that the base structure is established and stabilized, making subsequent thinning to uniform 5 nm thickness more controllable and less prone to defects
Solution Approach 2:
The invention uses a surface modifier composition as an intermediary substance that contains both polymer and solvent. The solvent allows for easy application and uniform distribution, while the polymer forms the cross-linked structure. This intermediary composition facilitates uniform thin layer formation that would be difficult to achieve with pure polymer application
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 method enables the formation of a thin surface-modified layer that enhances photoresist adhesion and resolution, reducing etching defects and improving lithography processes in EUV and electron beam lithography.
Implementation Method 1
baking the semiconductor substrate to cross-link the polymer and to form a surface-modified layer precursor
Implementation Method 2
bringing the surface-modified layer precursor into contact with a thinning liquid to thin the surface-modified layer precursor
Data Source
AI summary
A method for producing a laminate having a surface-modified layer and a semiconductor substrate includes: a first step of applying a surface modifier containing a polymer and a solvent to the semiconductor substrate, and then baking the semiconductor substrate to cross-link the polymer and to form a surface-modified layer precursor; and a second step of bringing the surface-modified layer precursor into contact with a thinning liquid to thin the surface-modified layer precursor and to form a surface-modified layer having a film thickness of 5 nm or less.