Silicon Underlayer Wet-Stripping via Local Quality
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Solution Overview
Problem
Conventional silicon-containing underlayers in photolithographic processes face challenges in pattern transfer due to their high silicon content, making them difficult to remove without damaging the substrate, especially when using fluorine-containing plasma or hydrofluoric acid, which also affect other materials.
Innovation Solution
A composition comprising solvents, a condensate or hydrolyzate of organic polymers with unsaturated monomers having acidic protons and condensable silicon-containing moieties, allowing for the formation of a wet-strippable polymeric underlayer that can be easily removed without damaging the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fluorine-containing plasma or hydrofluoric acid is used to remove the silicon-containing underlayer, then the underlayer can be removed, but the substrate and other materials are also damaged
Solution Approach 1:
The patent applies local quality by creating a underlayer with non-uniform silicon content distribution. The underlayer has a first region with higher silicon content (40-80%) providing etch resistance, and a second region with lower silicon content (0-20%) that is selectively removable. This spatial variation in composition allows different regions to serve different functions: one for protection during etching, another for easy removal after patterning.
Solution Approach 2:
The underlayer is segmented into functionally distinct regions with different silicon contents. The higher silicon content region segments the function of etch resistance, while the lower silicon content region segments the function of removability. This segmentation allows the underlayer to be removed selectively without damaging the substrate or other sensitive materials.
2Ease of manufacture
If higher concentrations of TMAH are used to remove the silicon-containing underlayer, then the underlayer can be removed, but the substrate is damaged
Solution Approach 1:
The patent changes the chemical composition parameter of the underlayer by controlling silicon content in different regions. The lower silicon content region (0-20%) changes the chemical resistance parameters, making it susceptible to removal by mild TMAH solutions (0.25-5%) without requiring high concentrations that would damage the substrate. This parameter change enables selective removal under gentler conditions.
3Manufacturing precision
If the silicon content in the underlayer is increased to improve etch resistance, then pattern transfer precision is improved, but the underlayer becomes difficult to remove
Solution Approach 1:
The patent applies local quality by creating a underlayer with non-uniform silicon content distribution. The underlayer has a first region with higher silicon content (40-80%) providing etch resistance, and a second region with lower silicon content (0-20%) that is selectively removable. This spatial variation in composition allows different regions to serve different functions: one for protection during etching, another for easy removal after patterning.
4Ease of manufacture
If the silicon content in the underlayer is decreased to make removal easier, then the underlayer can be removed more easily, but etch resistance is reduced
Solution Approach 1:
The underlayer is segmented into functionally distinct regions with different silicon contents. The higher silicon content region segments the function of etch resistance, while the lower silicon content region segments the function of removability. This segmentation allows the underlayer to be removed selectively without damaging the substrate or other sensitive materials.
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 solution enables efficient removal of the silicon-containing underlayer while protecting the substrate, maintaining high silicon content and etch resistance, and allowing for precise pattern transfer in photolithographic processes.
Implementation Method 1
a condensate or hydrolyzate of organic polymers with unsaturated monomers having acidic protons and condensable silicon-containing moieties
Implementation Method 2
a condensate or hydrolyzate of organic polymers with unsaturated monomers having acidic protons and condensable silicon-containing moieties
Implementation Method 3
The resistance of the silicon-containing underlayer toward oxide-etch chemistry allows this layer to function as an etch mask
Implementation Method 4
Fluorine-containing plasma and hydrofluoric acid (HF) can both be used to remove (or strip) these silicon-containing layers
Implementation Method 5
Fluorine-containing plasma and hydrofluoric acid (HF) can both be used to remove (or strip) these silicon-containing layers
Implementation Method 6
Wet stripping using tetramethylammonium hydroxide (TMAH) in higher concentrations, such as ≥5 wt %, can be used to remove at least some of these silicon-containing layers
Implementation Method 7
Silicon-containing layers having a relatively lower amount of silicon (≤17%) can sometimes be removed using 'piranha acid' (concentrated H2SO4+30% H2O2)
Data Source
AI summary
Methods of manufacturing electronic devices employing wet-strippable underlayer compositions comprising one or more condensed polymers having an organic polymer chain having pendently-bound moieties having an acidic proton and a pKa in water from −5 to 13 and having pendently-bound siloxane moieties are provided.