Dual-Tone Resist Composition for High-Resolution Lithography
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Solution Overview
Problem
Current microprocessing technologies for miniaturization, such as self-aligned double and quadruple patterning, and EUV lithography, face challenges in achieving high resolution and productivity while being costly, and existing dual-tone resist materials suffer from edge roughness and low contrast, limiting their effectiveness in forming patterns at small feature sizes.
Innovation Solution
A chemically amplified dual-tone resist composition is developed, utilizing a polymer with recurring units that form carboxyl groups for increased alkaline solubility and lactam cyclization to reduce dissolution rates, along with an acid generator to suppress acid diffusion, resulting in high resolution and minimal edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If self-aligned quadruple patterning (SAQP) process is used to achieve high resolution, then manufacturing precision is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent changes the chemical parameters of the resist material by incorporating specific polymer components (carboxyl-containing polymer and lactam-containing polymer) that respond differently to acid diffusion. This allows the resist to self-differentiate into high-resolution patterns through controlled acid propagation, eliminating the need for complex multi-step patterning processes while achieving comparable or superior resolution
Solution Approach 2:
The invention extracts the essential function of high-resolution patterning from the complex SAQP process and achieves it through a simplified single-exposure resist formulation. By taking out the core requirement (high resolution) and achieving it through material science rather than process complexity, the patent eliminates unnecessary process steps
2Manufacturing precision
If EUV lithography is used to achieve high resolution, then manufacturing precision is improved, but productivity decreases due to low laser power
Solution Approach 1:
The patent changes the resist material parameters to be highly sensitive to acid generation, allowing effective patterning with lower exposure energies. The specific polymer composition (including carboxyl groups and lactam structures) enables high-resolution patterning at reduced laser power while maintaining fast processing speeds, thus improving both resolution and productivity
3Manufacturing precision
If existing dual-tone resist materials are used to increase resolution, then manufacturing precision is improved, but contrast and resolution are insufficient
Solution Approach 1:
The patent uses a composite resist formulation containing multiple polymer components with complementary functions: carboxyl-containing polymer for acid sensitivity, lactam-containing polymer for contrast enhancement through acid-induced cyclization, and additional polymers for solubility control. This composite material approach achieves superior contrast and resolution compared to single-component dual-tone resists
Solution Approach 2:
The invention creates local quality differences within the resist film through spatially varying acid concentration after exposure. The acid diffusion creates a gradient that selectively triggers deprotection and cyclization reactions in specific regions, producing high-contrast patterns with excellent resolution. Different regions of the resist respond differently to the same exposure based on local acid concentration
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 resist composition achieves high resolution and minimal edge roughness, enabling effective pattern formation with improved contrast and reduced acid diffusion, suitable for VLSI and photomask fabrication.
Implementation Method 1
As the exposure dose increases, the acid generator having a high generation efficiency generates acid so that positive response manifests via deprotection
Implementation Method 2
a region receiving an increased exposure dose displays negative response because the base generator having a low generation efficiency generates an amount of base surpassing the amount of acid so that deprotection reaction may not occur
Implementation Method 3
recurring units that form carboxyl groups for increased alkaline solubility
Implementation Method 4
acid-induced lactam cyclization to reduce dissolution rate
Implementation Method 5
achieves high resolution, minimal edge roughness, and improved pattern formation with reduced acid diffusion
Data Source
AI summary
A resist composition comprising a polymer comprising recurring units (a) of formula (1) and having a Mw of 1,000-500,000 as base resin is provided. R1 is H or methyl, X is a single bond or —C(═O)—O—R5—, R2 is a single bond or C1-C4 alkylene, R3 is C2-C8 alkylene, R4 is an acid labile group, R5 is a single bond or C1-C4 alkylene, and 0<a≦̸1.0. The composition is of dual-tone type in that an intermediate dose region of resist film is dissolved in a developer, but unexposed and over-exposed regions of resist film are insoluble.