Silsesquioxane Mixture for Resist Etching Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing silsesquioxane compound mixtures used in positive resist compositions for semiconductor fabrication suffer from low shelf stability due to residual silanol groups and difficulty in incorporating bulky substituent groups, leading to reduced etching resistance and pattern collapse during microfabrication.
Innovation Solution
A method involving a two-stage condensation process of trifunctional silanes with bulky substituent groups, where the first stage involves hydrolysis and the second stage uses a strong base catalyst to achieve a high degree of condensation of 100%, allowing for the introduction of functional groups that enhance stability and etching resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single layer positive resist composition is used with thinner film for finer pattern, then pattern resolution is improved, but etching resistance becomes insufficient leading to pattern collapse
Solution Approach 1:
The invention divides the resist system into two functional layers: a thin positive resist layer for high-resolution patterning and a silsesquioxane-based intermediate film for etching resistance. This segmentation allows each layer to optimize its specific function without compromise.
Solution Approach 2:
The silsesquioxane compound combines organic functional groups with inorganic silicon oxide framework to create a composite material that simultaneously provides etching resistance, adhesion, and compatibility with photoresist materials.
2Strength
If silsesquioxane compounds with bulky substituent groups are used to improve etching resistance, then etching resistance is enhanced, but degree of condensation decreases due to steric hindrance
Solution Approach 1:
The patent performs preliminary hydrolysis of silane groups before condensation, converting them to more reactive silanol groups. This preliminary action reduces steric hindrance effects during the subsequent condensation reaction, enabling higher degree of condensation even with bulky substituent groups.
Solution Approach 2:
The invention changes the reaction parameters by using a two-stage process with controlled water content and temperature. The first stage uses excess water for hydrolysis, while the second stage controls water removal to promote complete condensation despite bulky groups.
3Ease of manufacture
If silsesquioxane compounds with silanol groups are used, then ease of manufacture is improved, but shelf stability deteriorates
Solution Approach 1:
The invention changes the condensation parameter by driving the reaction to complete condensation (100% degree) through controlled water removal and temperature management. This eliminates residual silanol groups that cause shelf instability while maintaining ease of manufacture.
Solution Approach 2:
The patent uses strong base catalysts (such as alkali metal hydroxides or quaternary ammonium hydroxides) to accelerate the condensation reaction, ensuring complete reaction and elimination of silanol groups that would otherwise remain and cause shelf stability problems.
4Strength
If intermediate film is added to provide etching resistance, then etching resistance is improved, but device complexity increases
Solution Approach 1:
The silsesquoxane intermediate film serves multiple functions simultaneously: it provides etching resistance, ensures good adhesion between the positive resist and substrate, and maintains compatibility with standard photolithography processes. This multi-functionality reduces the need for additional specialized layers.
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 resulting silsesquioxane compound mixture exhibits improved stability, increased proportion of 100% condensed species, and enhanced etching resistance, enabling finer pattern resolution and improved shelf stability in resist compositions.
Implementation Method 1
a first stage wherein a silane feed is hydrolyzed in the presence of an acid or base catalyst
Implementation Method 2
a second stage wherein dehydrating condensation reaction is carried out in the presence of at least 0.5 mol % based on the silane feed of a strong base catalyst
Data Source
AI summary
A silsesquioxane compound mixture having a high proportion of silsesquioxane compounds bearing bulky substituent groups on side chain and having a degree of condensation of substantially 100% is prepared by a first stage wherein a silane feed comprising a trifunctional silane bearing a bulky substituent group on side chain represented by formula (1):wherein Y is an aliphatic or aromatic organic group optionally having a functional group, X1, X2 and X3 are H, halogen, alkoxy or aryloxy is hydrolyzed in the presence of an acid or base catalyst, and a second stage wherein dehydrating condensation is carried out in the presence of a strong base catalyst while removing the water resulting from condensation out of the reaction system.