Resist Underlayer Film Composition for Semiconductor Etching Selectivity
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Solution Overview
Problem
In the multi-layer resist process, existing resist underlayer films lack insolubility in photoresist solutions and high etching selectivity, which hinders the formation of suitable patterns in semiconductor substrates.
Innovation Solution
A resist underlayer film-forming composition containing a polymer with specific groups, such as those represented by formula (1), which provides excellent solubility in solvents and high etching selectivity, is developed. This composition includes units like those represented by formulas (1a) and (1b), and is produced using materials like aldehydes, ketones, bisphenols, and heterocyclic compounds, enabling the formation of a resist underlayer film insoluble in photoresist solutions and suitable for high etching resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a novorak resin with specific substituents is used to form a resist underlayer film, then etching selectivity is improved, but solubility in the composition solvent deteriorates
Solution Approach 1:
The patent modifies the chemical structure of the novorak resin by changing parameters such as the types of substituents (introducing groups with formulas (1) and (2)), the degree of substitution, and the molecular weight distribution. These parameter changes optimize the balance between solubility in the composition solvent and insolubility in the photoresist solution, while maintaining high etching selectivity
Solution Approach 2:
The patent creates a composite polymer structure combining novorak resin units with specific aromatic and heterocyclic groups. This composite material approach allows the resist underlayer film to exhibit both good solubility in the composition solvent (due to specific functional groups) and high etching selectivity (due to the aromatic/heterocyclic structure), resolving the contradiction between these two properties
2Manufacturing precision
If the resist underlayer film is made insoluble in photoresist solution, then pattern formation quality is improved, but process complexity increases
Solution Approach 1:
The patent extracts and emphasizes the critical functional requirement of insolubility in photoresist solution by incorporating specific chemical groups (formulas (1) and (2)) that provide this property inherently at the molecular level. This extraction of the essential function into the material structure itself simplifies the overall process by eliminating the need for additional processing steps to achieve insolubility
3Reliability
If high etching selectivity is achieved through specific polymer structure, then etching performance is improved, but ease of synthesis deteriorates
Solution Approach 1:
The patent optimizes synthesis parameters including the choice of starting materials (aldehydes, phenols with specific structures), reaction conditions (catalysts, temperature, solvent), and the ratio of reactants. These parameter changes enable the synthesis of complex high-performance polymers through modified condensation reactions that are more practical and scalable while maintaining the required etching performance
Data Source
AI summary
A polymer to which there is attached a group represented by the following formula (1):(wherein each of Rx, Sy, and Sz represents a hydrogen atom or a monovalent organic group; each of Ry and Rz represents a single bond or a divalent organic group; each of ring Ary and ring Arz represents a C4 to C20 cyclic alkyl group or a C6 to C30 aryl group, and ring Ary and ring Arz may be linked together to form a new ring structure therebetween; ny is an integer of 0 to the maximum number corresponding to allowable substitution to ring Ary; nz is an integer of 0 to the maximum number corresponding to allowable substitution to ring Arz; and * is a polymer bonding site).