Resist Underlayer Film Material for Planarization and Etching Resistance
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Solution Overview
Problem
In semiconductor-device manufacturing, the miniaturization of patterns leads to reduced photoresist film thickness, lower resolution performance, and increased aspect ratios, resulting in pattern collapse and insufficient etching resistance, especially when using monolayer resist compositions. Additionally, existing resist underlayer films fail to provide adequate planarization, particularly on substrates with wide trench structures.
Innovation Solution
A resist underlayer film material comprising specific compounds with linear ether and aromatic moieties, combined with an organic solvent and optional additives like acid generators, surfactants, crosslinking agents, and pigments, is used to form a film with enhanced etching and optical properties, improved planarization, and filling capabilities, suitable for multilayer resist methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photoresist film thickness is reduced to maintain aspect ratio during pattern miniaturization, then pattern collapse is reduced, but etching resistance deteriorates
Solution Approach 1:
The patent divides the single photoresist film into multiple layers: a lower photoresist film directly on the substrate providing etching resistance, and an upper photoresist film for high-resolution patterning. This segmentation allows each layer to optimize for its specific function, resolving the contradiction between pattern stability and etching resistance.
Solution Approach 2:
The patent introduces a resist underlayer film as an intermediary between the substrate and the photoresist films. This underlayer provides additional etching resistance and planarization without interfering with the patterning function of the upper photoresist film, thereby maintaining both pattern stability and etching resistance.
2Manufacturing precision
If photoresist film thickness is reduced for finer patterning, then aspect ratio is reduced, but resolution performance deteriorates
Solution Approach 1:
The patent segments the photoresist system into upper and lower layers with different thicknesses optimized for different functions. The upper photoresist film can be thinner for fine patterning while the lower film provides additional thickness for resolution, resolving the contradiction between pattern fineness and resolution performance.
Solution Approach 2:
The patent applies different photoresist compositions and thicknesses to different locations in the resist stack. The upper photoresist film uses composition optimized for resolution with appropriate thickness for fine patterning, while the lower photoresist film provides supplementary thickness for resolution without compromising pattern fineness.
3Measurement precision
If resin is shifted to novolak resins or polyhydroxystyrene for higher resolution at shorter wavelengths, then resolution is improved, but etching resistance deteriorates
Solution Approach 1:
The patent assigns different resin types to different layers based on their optimal properties. The upper photoresist film uses novolak resins or polyhydroxystyrene optimized for high resolution at short wavelengths, while the lower photoresist film uses resins with high etching resistance, thereby achieving both high resolution and sufficient etching resistance.
Solution Approach 2:
The patent creates a composite resist structure combining different resin types in separate layers. The upper layer uses resolution-optimized resins (novolak, polyhydroxystyrene) while the lower layer uses etching-resistant resins, forming a composite system that achieves both high resolution and adequate etching resistance.
4Strength
If resist underlayer film is formed to improve etching resistance, then etching resistance is enhanced, but planarization capability deteriorates on wide trench substrates
Solution Approach 1:
The patent modifies the molecular structure parameters of the resist underlayer film by incorporating specific compounds with linear ether moieties and aromatic groups. These structural changes improve both the flow properties for planarization and the etching resistance, resolving the contradiction between etching resistance and planarization capability.
Solution Approach 2:
The patent creates a composite resist underlayer film combining compounds with specific molecular structures (linear ether moieties, aromatic groups) that provide both planarization capability through improved flow and etching resistance through enhanced chemical stability, achieving both planarization and etching resistance simultaneously.
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 resist underlayer film material effectively addresses the challenges of pattern miniaturization by providing excellent planarization and filling properties, reducing pattern collapse, and enhancing etching resistance, even on substrates with complex structures like wide trenches, while maintaining suitable optical properties for fine patterning in semiconductor manufacturing.
Implementation Method 1
heating to form a resist underlayer film
Implementation Method 2
optional additives like acid generators
Implementation Method 3
optional additives like crosslinking agents
Data Source
AI summary
A resist underlayer film material used in multilayer resist method contains (A) compound shown by following general formula (1), and (B) organic solvent, where X independently represents monovalent organic group shown by following general formula (2); W contains an “m” number of partial structures each independently shown by following formula (3); “m” and “n” each represent an integer of 1 to 10; broken lines represent bonding arms; Z represents aromatic group; A represents single bond or —O—(CH2)p—; “k” represents integer of 1 to 5; “p” represents integer of 1 to 10; R01 represents hydrogen atom or monovalent organic group having 1 to 10 carbon atoms. Material is capable of forming resist underlayer film excellent in planarizing property in fine patterning process by multilayer resist method in semiconductor-device manufacturing process; and patterning processes and methods for forming resist underlayer film use material.