Resist Underlayer Polymer End Groups for Thin EUV Film Uniformity
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Solution Overview
Problem
In the lithography process for semiconductor device manufacturing, forming a uniform resist underlayer film without defects at thin film thicknesses is challenging due to substrate surface influences and polymer properties, leading to issues like pinholes and agglomeration, while maintaining resist pattern adhesiveness and reducing Line Width Roughness (LWR) and improving resist sensitivity, especially with EUV exposure.
Innovation Solution
A resist underlayer film-forming composition containing a polymer with specific structural units, such as those represented by formulas (1) and (2), and an organic solvent, optionally with cross-linking agents or catalysts, to enhance film uniformity and adhesiveness, and improve etching rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the film thickness of the resist underlayer is reduced to enable EUV exposure with line width of 32 nm or less, then the resolution and sensitivity for fine patterning are improved, but film uniformity deteriorates due to pinholes and agglomeration caused by substrate surface influences and polymer properties
Solution Approach 1:
The patent changes the chemical parameters of the polymer by introducing specific functional groups (carboxyl, hydroxyl, or amine groups) at the terminal positions. This modifies the polymer's interaction with the substrate surface and its self-assembly behavior, enabling uniform film formation at reduced thicknesses without pinholes or agglomeration, thus resolving the contradiction between fine line width precision and film uniformity
Solution Approach 2:
The patent creates a composite structure by combining the polymer main chain with specific terminal functional groups that have different properties from the main chain. These terminal groups specifically interact with the substrate surface or resist film, creating a composite material that simultaneously achieves thin film uniformity and prevents defects like pinholes and agglomeration
2Strength
If a resist pattern is formed using a negative development process to improve adhesiveness, then the adhesiveness of the resist pattern is improved, but Line Width Roughness (LWR) deteriorates and resist sensitivity decreases
Solution Approach 1:
The patent applies local quality by placing specific functional groups only at the terminal positions of the polymer chains, rather than throughout the entire polymer structure. These terminal groups locally provide adhesiveness enhancement at the substrate interface while leaving the main polymer structure unchanged, thus improving adhesiveness without negatively affecting LWR or sensitivity
Solution Approach 2:
The patent segments the polymer structure into two functional parts: the main chain that provides mechanical properties and the terminal groups that provide chemical functionality for adhesion. This segmentation allows the terminal groups to specifically enhance adhesiveness through their functional groups while the main chain maintains the film's structural integrity, preventing LWR deterioration
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 effectively prevents LWR deterioration and enhances resist sensitivity, ensuring the formation of desired resist patterns with improved uniformity and reduced defects, particularly in EUV lithography.
Implementation Method 1
a polymer having a structure represented by formula (1) or (2) at an end of a polymer chain... forming a uniform film without defects, because pinholes, agglomeration, etc., are likely to occur due to the influence of the substrate surface
Data Source
AI summary
A composition for forming a resist underlayer film enables the formation of a desired resist pattern; and a method for forming a resist pattern using this resist underlayer film forming composition. A resist underlayer film forming composition contains an organic solvent and a polymer that has a structure represented by formula (1) or (2) at an end of the polymer chain. (In formula (1) and formula (2), X represents a divalent organic group; A represents an aryl group having 6-40 carbon atoms; R1 represents a halogen atom, an alkyl group having 1-40 carbon atoms or an alkoxy group having 1-40 carbon atoms; each of R2 and R3 independently represents a hydrogen atom, an optionally substituted alkyl group having 1-10 carbon atoms, an aryl group having 6-40 carbon atoms or a halogen atom; each of n1 and n3 independently represents an integer of 1-12; and n2 represents an integer of 0-11.)