Solution-Processed Underlayer Coatings for Lithography
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Solution Overview
Problem
Current underlayer materials for semiconductor devices face challenges such as high cost, inability to form planarizing layers over topography, high absorbance, and thermal instability, which affect pattern transfer and reflectivity in lithographic processes.
Innovation Solution
The development of coating compositions comprising a curable compound with an aromatic core and specific substituents, combined with solvents, to form a layer that functions as a photoresist underlayer, planarizing layer, or protective layer, capable of being cured at low temperatures and providing low reflectivity and etch selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CVD carbon materials are used for underlayer formation, then antireflective properties and etch selectivity are improved, but cost of ownership increases and ability to form planarizing layers over topography is lost
Solution Approach 1:
The invention changes the material parameters from CVD carbon to solution-processed polymers with high carbon content (e.g., polycarbonate, polyimide). This substitution maintains the necessary optical and etching properties while enabling spin-coating application, which provides planarization capability and reduces equipment cost.
Solution Approach 2:
The patent employs solution-processed polymer materials that are cheaper alternatives to CVD carbon. These materials can be applied via spin-coating using standard semiconductor manufacturing equipment, eliminating the need for expensive CVD chambers while achieving comparable performance for underlayer formation.
2Reliability
If CVD materials are used for underlayer formation, then etch selectivity is improved, but ability to form planarizing layer over topography is lost
Solution Approach 1:
The invention uses solution-processed materials that can be applied via spin-coating, a process that utilizes centrifugal force and capillary action to deposit and flatten the material conformally over substrate topography. This hydraulic/centrifugal approach enables planarization that gas-phase CVD cannot achieve.
3Ease of manufacture
If high-carbon content polymer materials are used for underlayer, then cost and planarizing capability are improved, but thermal stability above 400°C deteriorates
Solution Approach 1:
The patent employs composite material strategies by selecting or modifying polymer compositions to achieve both low-cost solution processing and high thermal stability. This may involve crosslinked polymer networks or composite structures that maintain integrity at temperatures above 400°C while remaining processable from solution.
4Ease of manufacture
If solution-processed high-carbon content materials are used, then equipment compatibility is improved, but thermal stability and resistance to solvent stripping deteriorates
Solution Approach 1:
The invention modifies the chemical parameters of solution-processed materials through polymer selection and formulation to achieve enhanced thermal stability and solvent resistance. This includes selecting polymers with high glass transition temperatures and strong intermolecular interactions that prevent solvent stripping while maintaining solution processability.
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 solution enables efficient pattern transfer, planarization, and thermal stability, reducing the cost and complexity of underlayer formation while maintaining antireflective properties and etch selectivity, thereby improving the overall lithographic process.
Implementation Method 1
coating compositions useful in forming electronic devices and for methods of using such compositions... a first curable compound... capable of being cured at low temperatures
Data Source
AI summary
Coating compositions comprise: a curable compound comprising: a core chosen from a C6 carbocyclic aromatic ring, a C2-5 heterocyclic aromatic ring, a C9-30 fused carbocyclic aromatic ring system, a C4-30 fused heterocyclic aromatic ring system, C1-20 aliphatic, and C3-20 cycloaliphatic, and three or more substituents of formula (1)wherein at least two substituents of formula (1) are attached to the aromatic core; provided that no substituents of formula (1) are in an ortho position to each other on the same aromatic ring of the core; a polymer; and one or more solvents, wherein the total solvent content is from 50 to 99 wt % based on the coating composition.