Silane-Based Resist Underlayer Composition for High Etching Rate
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Solution Overview
Problem
In the production of semiconductor devices, the reduction in resist film thickness in tri-layer processes leads to a decrease in etching rate of the resist underlayer film, which hampers the transfer of fine patterns to the underlayer film during dry etching.
Innovation Solution
A resist underlayer film-forming composition is used, which includes a hydrolysis condensate (polysiloxane) prepared through the hydrolysis and condensation of a hydrolyzable silane in a non-alcoholic solvent in the presence of a strong acid. This composition forms a resist underlayer film that can be removed chemically after substrate processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of organic component (functional groups and photoacid generator) is increased to improve lithographic properties, then adhesion to resist and resolution are improved, but etching rate is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the underlayer film by using silane compounds with specific organic groups (amino, carboxyl, hydroxyl, or a combination) instead of conventional organic components. This parameter change maintains lithographic properties while preserving high etching rate during dry etching process
Solution Approach 2:
The patent creates a composite underlayer film by combining silane-based inorganic components with specific organic functional groups. This composite structure provides both the necessary adhesion and chemical stability for lithography and the required etching rate for pattern transfer
2Manufacturing precision
If resist film thickness is reduced for fine processing, then resolution is improved, but etching rate of underlayer film is reduced
Solution Approach 1:
The patent modifies the chemical composition parameters of the underlayer film using silane compounds with specific organic functional groups, enabling the film to maintain high etching rate even when resist film thickness is reduced for fine pattern processing
3Reliability
If conventional silane compounds with onium groups are used, then adhesion is improved, but etching rate is reduced due to hydrolysis in alcoholic solvent
Solution Approach 1:
The patent extracts the problematic onium group (ammonium, sulfonium, iodonium, or phosphonium) from the silane compound structure and replaces it with alternative organic groups (amino, carboxyl, hydroxyl, or combinations) that do not cause hydrolysis in alcoholic solvents, thereby maintaining adhesion while preserving etching rate
Solution Approach 2:
The patent changes the functional group parameters of the silane compound from onium groups to non-onium organic groups, fundamentally altering the chemical behavior during hydrolysis and eliminating the etching rate reduction problem
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 a high etching rate during halogen gas etching, ensuring effective pattern transfer to the underlayer film while allowing for chemical removal of the resist underlayer film after processing, thus maintaining substrate integrity.
Implementation Method 1
a hydrolysis condensate prepared through hydrolysis and condensation of a hydrolyzable silane in a non-alcoholic solvent in the presence of a strong acid
Implementation Method 2
hydrolysis and condensation of a hydrolyzable silane in a non-alcoholic solvent in the presence of a strong acid
Implementation Method 3
removing the patterned resist film, the patterned resist underlayer film, and/or particles with a sulfuric acid-hydrogen peroxide mixture (SPM) prepared by mixing of aqueous hydrogen peroxide with sulfuric acid and/or an ammonia-hydrogen peroxide mixture (SC1) prepared by mixing of aqueous hydrogen peroxide with aqueous ammonia
Data Source
AI summary
A composition for forming a resist underlayer film containing a hydrolysis condensate prepared through hydrolysis and condensation of a hydrolyzable silane, wherein the hydrolyzable silane contains a hydrolyzable silane of Formula (1):R1aR2bSi(R3)4−(a+b) Formula (1)wherein R1 is an organic group having a primary amino group, a secondary amino group, or a tertiary amino group and is bonded to a silicon atom via an Si—C bond; R2 is an alkyl group, an aryl group, a halogenated alkyl group, a halogenated aryl group, an alkoxyaryl group, an alkenyl group, an acyloxyalkyl group, or an organic group having an acryloyl group, a methacryloyl group, a mercapto group, an amino group, an amide group, a hydroxyl group, an alkoxy group, an ester group, a sulfonyl group, or a cyano group, or any combination of these groups, and is bonded to a silicon atom via an Si—C bond; R1 and R2 are optionally bonded together to form a ring structure; R3 is an alkoxy group, an acyloxy group, or a halogen group; a is an integer of 1; b is an integer of 0 to 2; and a+b is an integer of 1 to 3; and the hydrolysis condensate contains an organic group having a salt structure formed between a counter anion derived from a nitric acid and a counter cation derived from a primary ammonium group, a secondary ammonium group, or a tertiary ammonium group.