Spin-Coated Curable Film Planarization for Nanometer Flatness
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Solution Overview
Problem
Existing photolithography techniques, particularly extreme ultraviolet exposure, face challenges in achieving sufficient surface planarization of substrates due to the decrease in depth of focus with miniaturization, necessitating a method to flatten substrate surfaces to a few nanometers or less.
Innovation Solution
A film forming method using a curable composition containing a polymerizable compound and solvent, applied via spin coating, where the viscosity of the composition after solvent removal is controlled to form a film with high flatness, utilizing a specific viscosity function based on substrate concave-convex shape and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spin coating method is used to form underlayer film, then film formation is achieved, but sufficient flatness cannot be obtained
Solution Approach 1:
The patent changes the viscosity parameter of the curable composition by controlling the solvent content and composition type. By adjusting these parameters, the composition achieves optimal flowability during spin coating to fill substrate concave-convex shapes, thereby obtaining flat films without requiring additional heating steps.
Solution Approach 2:
The patent introduces a specifically designed curable composition as an intermediary material between the spin coating process and the final flat film. This composition acts as a mediator that enables the spin coating method to achieve flatness by its unique viscosity and flow characteristics.
2Manufacturing precision
If viscosity is lowered by heating to promote flowability, then flatter film is formed, but process complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-formulating the curable composition with optimized solvent content and type before the spin coating process. This preliminary preparation ensures the composition has the correct viscosity and flowability built-in, eliminating the need for subsequent heating steps to achieve flatness.
Solution Approach 2:
The patent extracts and removes the heating step from the conventional process sequence. By incorporating the flowability enhancement directly into the composition formulation itself, the patent eliminates the need for separate thermal processing steps.
3Measurement precision
If depth of focus is increased for photolithography, then imaging quality improves, but requires stricter surface flatness control
Solution Approach 1:
The patent applies self-service by designing the curable composition to automatically adapt to substrate surface conditions during spin coating. The composition's specific viscosity and flow characteristics enable it to self-level and fill concave-convex shapes without external intervention, thereby achieving the required flatness for enhanced depth of focus.
Solution Approach 2:
The patent changes the composition parameters (solvent content, composition type) to achieve optimal flowability that matches the substrate surface conditions. This parameter optimization enables the composition to naturally conform to and flatten the substrate surface, providing the flatness required for improved photolithography depth of focus.
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 achieves high flatness of the film at room temperature, improving planarization and enhancing the depth of focus in photolithography processes.
Implementation Method 1
a viscosity μ [mPa·s] of a composition obtained by removing the solvent from the curable composition is smaller than a value of a function f determined by a period λ [μm] of a concave-convex shape of the substrate and a thickness df [nm] of the curable composition after curing
Implementation Method 2
arranging a curable composition containing a polymerizable compound and a solvent on a substrate using a spin coating method
Implementation Method 3
curable composition containing a polymerizable compound
Data Source
AI summary
A film forming method including arranging a curable composition containing a polymerizable compound and a solvent on a substrate using a spin coating method, and planarizing the curable composition arranged on the substrate to form a film, wherein a viscosity μ [mPa·s] of a composition obtained by removing the solvent from the curable composition is smaller than a value of a function f determined by a period λ [μm] of a concave-convex shape of the substrate and a thickness df [nm] of the curable composition after curing.