Stepped Substrate Coating Composition for Planar Underlayers
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Solution Overview
Problem
Conventional photo-crosslinkable materials for resist underlayer films face issues with insufficient pattern filling and impaired planarity due to increased viscosity and thermal shrinkage caused by crosslinking reactions and degassing during heating or photoirradiation.
Innovation Solution
A stepped substrate coating composition comprising a main agent with specific compounds that undergo photocrosslinking or thermal curing, preventing viscosity increase and thermal shrinkage, and ensuring planarity by forming a crosslinked structure through epoxy groups or unsaturated bonds, without relying on thermally crosslinkable moieties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional photo-crosslinkable material containing a polymer with thermally crosslinkable functional groups (e.g., hydroxy groups), crosslinking agent, and acid catalyst is heated to fill a pattern, then the crosslinking reaction proceeds, but viscosity increases resulting in insufficient pattern filling
Solution Approach 1:
The patent changes the crosslinking mechanism from thermal to photo-induced. The composition uses a photoacid generator that decomposes upon light irradiation to produce acid, which then catalyzes crosslinking of epoxy groups. This parameter change allows crosslinking to occur at lower temperatures and shorter times, preventing viscosity increase that would block pattern filling
Solution Approach 2:
The patent replaces thermal energy with optical energy to initiate the crosslinking reaction. Instead of using heat to activate the crosslinking process, the invention uses light irradiation to decompose the photoacid generator and produce acid catalysts, thereby substituting a thermal-mechanical process with an optical-chemical process that better controls viscosity
2Stability of the object's composition
If a resist underlayer film-forming composition containing a polymer with cationic polymerizable reactive groups and a large amount of acid generator is used, then photocuring occurs, but thermal shrinkage due to degassing impairs planarity
Solution Approach 1:
The patent uses a composite material system combining epoxy groups (for crosslinking), vinyl groups (for polymerization), and a photoacid generator. This composite approach allows dual functionality: crosslinking provides structural stability while vinyl polymerization can occur without significant gas evolution, maintaining film planarity during curing
Solution Approach 2:
The patent optimizes the type and amount of photoacid generator to control the curing process. By selecting appropriate photoacid generators and controlling their concentration, the invention achieves complete photocuring while minimizing thermal shrinkage and degassing effects that would compromise planarity
3Manufacturing precision
If exposure light with shorter wavelength is used for finer resist pattern formation, then finer patterns can be created, but depth of focus decreases requiring improved film planarity
Solution Approach 1:
The patent applies preliminary planarization by forming a resist underlayer film with excellent flatness before applying the resist pattern. This preliminary action compensates for substrate irregularities and ensures that even when using short-wavelength exposure light with limited depth of focus, the entire pattern area remains within the focal plane, enabling precise pattern formation
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 sufficient pattern filling and excellent planarity by preventing thermal shrinkage and maintaining film flatness, even on substrates with dense and coarse patterns, through controlled photocrosslinking and thermal curing processes.
Implementation Method 1
a photoacid generator which is decomposed by light irradiation to generate acid
Implementation Method 2
the acid generated reacts with epoxy groups to promote crosslinking reaction
Implementation Method 3
the acid generated reacts with vinyl groups to promote polymerization reaction
Data Source
AI summary
A stepped substrate coating composition for forming a coating film having planarity on a substrate, including: a main agent and a solvent, the main agent containing a compound (A), a compound (B), or a mixture thereof, the compound (A) having a partial structure Formula (A-1) or (A-2):and the compound (B) having at least one partial structure selected from Formulae (B-1)-(B-5), or having a partial structure including a combination of a partial structure of Formula (B-6) and a partial structure of Formula (B-7) or (B-8):where the composition is cured by photoirradiation or by heating at 30° C.-300° C.; and the amount of the main agent in the solid content of the composition is 95%-100% by mass.