Resist Underlayer Film Composition for Lithography Etching Selectivity
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Solution Overview
Problem
In semiconductor manufacturing, the increasing complexity of devices requires a resist underlayer film that can function as a mask with a dry etching selection ratio close to that of the resist or semiconductor substrate, while also addressing issues of pattern resolution and anti-reflective coating, without intermixing with inorganic hard mask layers and maintaining thermal stability.
Innovation Solution
A resist underlayer film-forming composition comprising a polymer with an acrylamide or acrylic acid ester structure, a blocked isocyanate polymer, and a solvent, which forms a film that can be dry-etched and removed with an alkaline aqueous solution, providing anti-reflective properties and preventing contamination during high-temperature processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional high etch rate resist underlayer film is used, then the etching speed is improved, but the selection ratio of dry etching rate becomes too high compared to the resist and semiconductor substrate
Solution Approach 1:
The patent changes the chemical composition parameters of the resist underlayer film by incorporating specific polymers (polymer A with acrylamide or acrylic acid ester structure, polymer B with blocked isocyanate structure) and controlling their ratios, to adjust the dry etching rate selection ratio to be close to or lower than that of the resist and semiconductor substrate
Solution Approach 2:
The patent uses a composite material system consisting of polymer A (acrylamide or acrylic acid ester structure), polymer B (blocked isocyanate structure), and solvent C, where the interaction between these components creates a resist underlayer film with optimized etching properties and selection ratio
2Manufacturing precision
If the film thickness of resist is reduced to improve resolution, then the resolution is improved, but the film thickness becomes insufficient for processing the substrate
Solution Approach 1:
The patent makes the resist underlayer film serve multiple functions: it acts as both an anti-reflective coating to improve resolution and as a functional mask for substrate processing, eliminating the need for separate layers and allowing thinner resist films to be used effectively
3Manufacturing precision
If a resist underlayer film is used to improve anti-reflective performance, then the anti-reflective performance is improved, but intermixing with inorganic hard mask layer occurs
Solution Approach 1:
The patent optimizes the compositional parameters by selecting specific polymer types and ratios (polymer A with acrylamide or acrylic acid ester structure, polymer B with blocked isocyanate structure) to achieve a film that provides anti-reflective performance while maintaining compositional stability and preventing intermixing with inorganic hard mask 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 composition enables the formation of a resist pattern with excellent shape retention, dry etching selectivity, and anti-reflective performance, facilitating precise lithography and preventing contamination during substrate processing.
Implementation Method 1
the polymer (B) has a blocked isocyanate structure... the polymer (A) and the polymer (B) are included such that a molar ratio of the hydroxy group or the carboxy group to the blocked isocyanate group is 1:0.005 to 1.0
Implementation Method 2
impart, to a resist underlayer film, the performance of effectively absorbing light reflected on a substrate when irradiated light having a wavelength of, for example, 248 nm, 193 nm, or 157 nm is used for fine processing
Implementation Method 3
capable of being dry-etched during pattern transfer from the upper layer or during substrate processing and capable of being removed with an alkaline aqueous solution after the substrate processing
Data Source
AI summary
A resist underlayer film-forming composition for lithography capable of being dry-etched during pattern transfer from the upper layer or during substrate processing and capable of being removed with an alkaline aqueous solution after the substrate processing. The composition includes a polymer (A) having an acrylamide structure or an acrylic acid ester structure; a polymer (B) having a blocked isocyanate structure; and a solvent (C). The polymer (A) is a polymer including a unit structure of Formula (1). The polymer (B) is a polymer including a unit structure of Formula (2). A method for manufacturing a semiconductor device includes steps for: forming a resist pattern; etching an inorganic hard mask layer with use of the resist pattern; etching a resist underlayer film with use of the pattered inorganic hard mask layer; and processing a semiconductor substrate with use of the pattered resist underlayer film.