Lithography Surface Modification Layer for Water Stain Reduction
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Solution Overview
Problem
In advanced integrated circuit fabrication, the formation of patterned photoresist layers often results in defects such as water stains and solvent remains, which reduce image quality and cause patterning issues, especially in multiple patterning processes used in advanced technology nodes.
Innovation Solution
A lithography method involving a surface modification layer with a hydrophilic top surface is introduced, which is applied on top of a bottom anti-reflective coating layer or a tri-layer photoresist structure, enhancing the hydrophilicity to reduce water stains and solvent retention during the lithography process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a photoresist layer is used to transfer patterns in advanced technology nodes, then pattern density and feature size reduction are achieved, but water stains and solvent remains are formed on the photoresist layer
Solution Approach 1:
A surface modification layer is introduced as an intermediary between the substrate and the photoresist layer. This intermediate layer modifies the surface properties to prevent water and solvent accumulation, thereby eliminating the harmful effects while maintaining the benefits of high pattern density.
Solution Approach 2:
The surface energy parameters of the substrate are changed by applying a surface modification layer. This layer alters the wettability characteristics, making the surface more hydrophilic and less prone to water stain formation, thus resolving the contradiction between high pattern density and defect formation.
2Manufacturing precision
If multiple patterning techniques are used to reduce feature size, then pattern density increases, but the formation of water stains and solvent remains becomes more problematic
Solution Approach 1:
The surface modification layer serves as a mediator that protects the photoresist layer from water and solvent contamination during multiple patterning processes. This intermediary layer enables the execution of multiple patterning techniques without the compounding effect of water stains and solvent remains.
Solution Approach 2:
The surface modification layer is applied in advance before the multiple patterning process begins. This preliminary action prepares the surface to resist water and solvent contamination throughout the subsequent patterning steps, preventing defect accumulation as pattern density increases.
3Strength
If the photoresist layer is made thicker to provide etch resistance, then etching resistance improves, but coating uniformity and defect formation are affected
Solution Approach 1:
The protective function is segmented from the photoresist layer and assigned to a separate surface modification layer. This segmentation allows the photoresist layer to maintain optimal thickness for coating uniformity while the surface modification layer provides the necessary protection against water stains and solvent remains.
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 effectively eliminates or reduces defects in patterned photoresist layers, maintaining the anti-reflective and etching resistance properties of the bottom anti-reflective coating layer while improving coating uniformity and reducing the need for additional cleaning solutions like FIRM or nitrogen purge.
Implementation Method 1
forming a surface modification layer on a substrate, the surface modification layer including a hydrophilic top surface
Implementation Method 2
enhancing the hydrophilicity to reduce water stains and solvent retention during the lithography process
Data Source
AI summary
A lithography method is provided in accordance with some embodiments. The lithography method includes forming a surface modification layer on a substrate, the surface modification layer including a hydrophilic top surface; coating a photoresist layer on the surface modification layer; and developing the photoresist layer, thereby forming a patterned photoresist layer.