Polyether Resin Underlayer Film for Lithography Anti-Reflection
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Solution Overview
Problem
In semiconductor device production, the high integration of devices and use of shorter wavelength active rays in lithography processes lead to issues with diffused reflection and standing waves, requiring a resist underlayer film that can prevent intermixing with the resist layer, provide excellent resist patterns, and offer specific dry etching rate selection ratios, while also absorbing light effectively and offering heat resistance.
Innovation Solution
A resist underlayer film forming composition containing polymers with specific unit structures, such as those with arylene or fluorene groups, which form a film that acts as an anti-reflective coating and has a dry etching rate selection ratio close to or less than that of the resist or semiconductor substrate, and provides heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional high etching rate resist underlayer film is used, then the dry etching rate selection ratio is high, but the film cannot provide sufficient heat resistance and may cause intermixing with the resist layer
Solution Approach 1:
The patent employs composite material strategy by combining specific polymer components (polymer A containing sulfonic acid groups, polymer B containing carboxylic acid groups, and polymer C containing hydroxyl groups) in defined ratios to create a resist underlayer film that simultaneously achieves heat resistance, prevents intermixing, and provides appropriate etching selectivity. The composite composition allows the film to maintain structural integrity at high temperatures while controlling chemical interactions with the overlying resist layer.
2Manufacturing precision
If the resist film thickness is reduced to prevent pattern collapse, then the resolution is improved, but the resist pattern film thickness becomes insufficient for processing the substrate
Solution Approach 1:
The patent divides the protective function into two segments: the thin resist pattern layer provides high-resolution patterning, while the separately applied resist underlayer film provides the necessary mechanical strength and etching protection. This segmentation allows the resist pattern to be thin enough for high resolution while the underlayer compensates for the reduced thickness by providing the required film integrity during substrate processing.
3Reliability
If a resist underlayer film with etching rate matching the resist is used, then the selection ratio is optimized, but the film may not provide sufficient anti-reflective coating performance
Solution Approach 1:
The patent designs the resist underlayer film to perform multiple functions simultaneously: (1) providing appropriate dry etching rate selection ratio for pattern transfer, (2) acting as an anti-reflective coating to suppress standing waves during lithography, (3) offering heat resistance to prevent intermixing, and (4) ensuring mechanical stability. The multi-functional composition achieves these diverse requirements through the synergistic combination of polymer components with specific chemical groups and their controlled ratios.
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 composition effectively suppresses reflection, prevents pattern collapse, and allows for accurate resist pattern formation with high thermal stability, enabling precise processing of semiconductor substrates.
Implementation Method 1
capable of imparting performance of effectively absorbing light reflected on the substrate when irradiated light having a wavelength of 248 nm, 193 nm, 157 nm, or the like is used for fine processing
Implementation Method 2
providing heat resistance and allowing for accurate resist pattern formation with high thermal stability
Data Source
AI summary
A method for producing a semiconductor device, which includes forming an underlayer film on a semiconductor substrate with a resist underlayer film forming composition that contains a solvent, and a polymer containing a unit structure of Formula (2):O—Ar2—O—Ar3-T-Ar4 Formula (2)where Ar2, Ar3, and Ar4 are individually a C6-50 arylene group or an organic group containing a heterocyclic group; at least one of Ar3 and Ar4 is a phenylene group; and T is a carbonyl group. The resist underlayer film forming composition has a solid content of 0.1 to 70 mass % of a total mass of the composition.