Aromatic Underlayer for Semiconductor Planarization
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Solution Overview
Problem
Current underlayer materials for semiconductor manufacturing, such as chemical vapor deposited carbon, face limitations including high cost, inability to form planarizing layers over topography, and high absorbance, prompting the need for alternative materials that can be thermally set at lower temperatures and provide antireflective and etch selectivity properties.
Innovation Solution
Aromatic core-based curable compounds with specific substituents are used to form an underlayer, which are coated on a substrate, cured, and then used in conjunction with photoresist layers to transfer patterns, allowing for efficient semiconductor manufacturing while meeting the requirements of thermal stability and planarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CVD carbon is used as underlayer material, then antireflective properties and etch selectivity are provided, but cost of ownership increases and ability to form planarizing layer over topography is lost
Solution Approach 1:
The patent replaces expensive CVD carbon with inexpensive spin-coat polymer materials that can be deposited as thin underlayer films. The polymer composition provides the necessary antireflective and etch selectivity properties at a fraction of the cost of CVD processes, making the manufacturing more economical while maintaining functional performance.
Solution Approach 2:
The patent changes the material state from solid CVD carbon to solution-processable polymer that can be spin-coated. This parameter change enables the formation of planarizing layers over substrate topography, which is impossible with conventional CVD carbon deposition methods.
2Reliability
If CVD carbon is used as underlayer material, then antireflective properties are provided, but ability to form planarizing layer over topography is lost
Solution Approach 1:
The patent uses spin-coating, a liquid-based deposition method, to apply the polymer underlayer material. This hydraulic approach allows the liquid polymer to flow into and planarize substrate topography features, creating a flat surface for subsequent lithography steps, which is not achievable with gas-phase CVD carbon deposition.
3Reliability
If CVD carbon is used as underlayer material, then etch selectivity is provided, but high absorbance at 633 nm for pattern alignment occurs
Solution Approach 1:
The patent modifies the optical parameters of the underlayer material by selecting polymer compositions with appropriate refractive index (n) and extinction coefficient (k) values. These parameter changes reduce absorbance at the 633 nm alignment wavelength while preserving etch selectivity, enabling both alignment and etching functions to be performed effectively.
4Reliability
If high-carbon content polymer is used as underlayer, then antireflective properties are provided, but thermal stability up to 400°C is required without damage
Solution Approach 1:
The patent employs composite polymer formulations combining high-carbon content components for antireflective properties with thermally stable additives and crosslinking agents. This composite approach enables the underlayer to withstand 400°C processing temperatures without degradation while maintaining the desired optical properties for lithography.
Solution Approach 2:
The patent utilizes thermal curing processes that induce phase transitions in the polymer matrix, transforming the underlayer from a thermoplastic state to a thermoset state. This phase change enhances thermal stability and dimensional integrity at 400°C while preserving the antireflective characteristics necessary for photoresist imaging.
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 aromatic core-based underlayer materials enable effective pattern transfer and planarization, reducing defects and improving manufacturing efficiency by providing low reflectivity and etch selectivity, while being thermally stable and cost-effective.
Implementation Method 1
coating a layer of a coating composition comprising one or more curable compounds on a surface of the electronic device substrate... curing the layer of the curable compound to form an underlayer... exposing the photoresist layer to actinic radiation
Implementation Method 2
thermal-set upon heating with low out-gassing and sublimation... thermally stable up to >400° C.
Data Source
AI summary
Compounds having three or more alkynyl moieties substituted with an aromatic moiety having one or more of certain substituents are useful in forming underlayers useful in semiconductor manufacturing processes.