Alicyclic Epoxy Resist Underlayer for Semiconductor Flattening
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Solution Overview
Problem
Conventional anti-reflective coatings for semiconductor substrates fail to adequately address the need for high embeddability in recesses and flattening properties, often resulting in pattern edge collapse and resolution failures due to standing waves and film shrinkage during curing.
Innovation Solution
A resist underlayer film-forming composition incorporating an alicyclic epoxy compound with multiple epoxy groups and a light absorption moiety, which suppresses film shrinkage and detachment, and does not require a crosslinker, allowing for improved embeddability and flattening of substrates with recesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crosslinker is used to enhance the anti-reflective coating properties, then the light absorbance and radiation resistance are improved, but film shrinkage during curing increases and embeddability in recesses deteriorates
Solution Approach 1:
The patent removes the crosslinker component from the anti-reflective coating formulation. By extracting this problematic element, the coating achieves curing through alternative mechanisms that do not produce film shrinkage, thereby maintaining embeddability in recesses while still providing the necessary anti-reflective properties through carefully selected polymer and additive combinations
Solution Approach 2:
The patent modifies the chemical composition parameters of the coating by selecting specific polymers with appropriate functional groups and controlling the ratios of light-absorbing substances and additives. This parameter optimization allows the coating to achieve sufficient crosslinking density and anti-reflective performance without relying on traditional crosslinkers that cause shrinkage
2Object-affected harmful factors
If the anti-reflective coating is designed to have high light absorbance, then the standing wave suppression is improved, but the intermixing with photoresist layer increases
Solution Approach 1:
The patent applies local quality by creating a coating with spatially differentiated properties: the upper region contains light-absorbing substances and polymers optimized for anti-reflective performance, while the lower region near the photoresist interface uses carefully selected materials with compatible solubility characteristics. This gradient structure allows high light absorbance without causing intermixing with the photoresist layer
Solution Approach 2:
The patent employs composite material design by combining multiple polymers with different functional groups (carboxyl, hydroxy, amino) and light-absorbing substances in a single coating formulation. This composite structure enables the coating to simultaneously achieve high light absorbance for standing wave suppression and chemical compatibility with the photoresist layer through selective interaction mechanisms
3Ease of manufacture
If conventional acrylic resin is used for the anti-reflective coating, then the film-forming simplicity is maintained, but the embeddability in recess and flattening properties are insufficient
Solution Approach 1:
The patent transitions from simple acrylic resin to a composite coating system incorporating multiple polymer types with specific functional groups and light-absorbing substances. This composite formulation maintains ease of manufacture through a single-coat application process while achieving superior embeddability and flattening properties through the synergistic effects of the combined materials
Solution Approach 2:
The patent changes the chemical parameters of the coating by introducing polymers with carboxyl, hydroxy, and amino groups that provide enhanced adhesion and flow characteristics. These parameter modifications enable the coating to effectively fill recesses and flatten substrate irregularities while maintaining a simple single-step application process
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 achieves excellent dry etching rates and uniform film thickness, preventing intermixing with photoresist layers and enabling precise pattern formation on substrates with complex geometries.
Implementation Method 1
containing (A) an alicyclic epoxy compound having an alicyclic skeleton and one or more epoxy groups, and a light absorption moiety, in the molecule, (B) a thermal acid generator
Implementation Method 2
Cationically polymerizable resist underlayer film-forming composition for lithography that functions as an anti-reflective coating during exposure and can flatten a semiconductor substrate having a recess by embedding using a liquid epoxy compound
Implementation Method 3
an organic anti-reflective coating formed from a light absorbing substance, a polymer, and the like has been variously investigated as the anti-reflective coating
Data Source
AI summary
There is provided a composition for forming a resist underlayer film for lithography that can be used as an underlayer anti-reflective coating that decreases the reflection of irradiated light during exposure from a semiconductor substrate toward the photoresist layer that is formed on the semiconductor substrate and in particular, can be suitably used as a flattening film for flattening a semiconductor substrate having a recess and a project by embedding, in a lithography process for production of a semiconductor device. A resist underlayer film-forming composition for lithography comprising (A) an alicyclic epoxy compound having an alicyclic skeleton and one or more epoxy groups, and a light absorption moiety, in the molecule, (B) a thermal acid generator, and (C) a solvent.