Polymer Hardmask for Ultra-Fine Lithography
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Solution Overview
Problem
Current lithographic techniques face challenges in forming fine patterns with excellent profiles on semiconductor substrates, particularly due to limitations in heat resistance and etch resistance of hardmask layers, especially when using the spin-on coating method for gap-fill and planarization in ultra-fine techniques.
Innovation Solution
A novel polymer with specific structural units, represented by Chemical Formulae 1 and 2, is developed, which provides improved heat resistance and etch resistance, used in an organic layer composition that forms a hardmask layer through spin-on coating, enabling enhanced film density and planarization, and is applied in a method involving heat-treating, forming a silicon-containing thin layer, and selective etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hardmask layer is formed using conventional materials and methods, then the basic pattern transfer function is achieved, but the heat resistance and etch resistance are insufficient for ultra-fine patterning
Solution Approach 1:
The patent employs a composite polymer structure combining aromatic rings (for heat/etch resistance) with aliphatic chains and polar groups (for solubility). Specifically, the polymer includes rigid aromatic moieties like naphthalene or anthracene units linked with flexible chains containing ester groups, creating a material that simultaneously achieves high thermal stability, etch resistance, and sufficient solubility for spin-on coating processing.
Solution Approach 2:
The patent systematically varies polymer parameters including molecular weight (5,000-100,000), aromatic ring substitution patterns, chain length, and functional group types to optimize the balance between resistance properties and solubility. By controlling the weight ratio of aromatic to aliphatic portions and adjusting molecular weight distribution, the material achieves the required performance window for ultra-fine patterning applications.
2Ease of manufacture
If the spin-on coating method is used to form the hardmask layer, then ease of manufacture and gap-fill characteristics are improved, but film density and planarization are insufficient
Solution Approach 1:
The patent optimizes coating parameters including solution concentration (0.1-10 wt%), spin speed (1,000-5,000 rpm), and thermal treatment conditions (80-200°C for 1-60 minutes) to achieve dense, planarized films. The polymer's specific molecular structure enables proper chain packing and intermolecular interactions during spin-on coating and annealing, resulting in films with high density and excellent surface flatness despite the simplicity of the spin-on method.
Solution Approach 2:
The patent designs the polymer with localized functional regions: aromatic rings provide local rigidity and resistance, while aliphatic chains with polar groups provide local flexibility and intermolecular bonding. This local quality differentiation enables the film to simultaneously achieve density, planarization, and resistance properties through the spin-on coating process.
3Manufacturing precision
If conventional photoresist and etching processes are used, then the basic lithographic workflow is maintained, but fine pattern profile and precision are insufficient
Solution Approach 1:
The patent designs the polymer to perform multiple functions simultaneously: it serves as the hardmask layer providing etch resistance, as a planarization layer ensuring surface flatness, and as a gap-fill material achieving void-free pattern formation. This multi-functionality eliminates the need for separate dedicated layers, maintaining a relatively simple process while achieving superior pattern precision through the polymer's integrated performance.
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 polymer-based hardmask layer exhibits improved etch resistance and film density, allowing for precise pattern formation without voids or thickness distribution issues, even on substrates with steps or patterned regions, thereby overcoming the limitations of existing hardmask materials.
Implementation Method 1
a spin-on coating method instead of a chemical vapor deposition (CVD) method has recently been suggested to form the hardmask layer
Implementation Method 2
heat-treating the organic layer composition to form a hardmask layer
Implementation Method 3
exposing and developing the same to provide a photoresist pattern
Implementation Method 4
etching a material layer using the photoresist pattern as a mask
Data Source
AI summary
Disclosed are a polymer including a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2, an organic layer composition including the polymer, and a method of forming patterns using the organic layer composition.The Chemical Formulae 1 and 2 are the same as defined in the specification.