Resist Topcoat Composition for EUV Lithography Pattern Uniformity
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Solution Overview
Problem
In photolithographic processes for semiconductor manufacturing, extreme ultraviolet (EUV) exposure leads to pattern distribution deterioration due to uneven light irradiation and absorption differences within the photoresist, resulting in increased line edge roughness (LER), line width roughness (LWR), and in-point uniformity (IPU) issues.
Innovation Solution
A resist topcoat composition comprising a copolymer with specific structural units and an ether-based solvent is applied to the photoresist film, which enhances EUV absorption, reduces acid concentration, and improves solubility, thereby minimizing pattern roughness and uniformity issues by removing excessive activated acid and controlling etching during development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If EUV irradiation is applied to photoresist, then pattern formation capability is improved, but pattern distribution deterioration occurs due to uneven light absorption and photo shot noise
Solution Approach 1:
A topcoat layer comprising a copolymer of formula (1) is applied over the photoresist layer as an intermediary substance. This topcoat absorbs excess EUV energy and regulates acid generation, preventing uneven light absorption effects in the underlying photoresist and thereby maintaining pattern distribution uniformity while enabling EUV-based pattern formation
Solution Approach 2:
The copolymer in the topcoat is specifically designed with adjustable compositional parameters ( ratios of structural units A and B, molecular weight, functional group content) to optimize EUV absorption characteristics and acid generation regulation, allowing precise control over the energy distribution and pattern formation process
2Area of stationary object
If photoresist layer thickness is increased to improve pattern coverage, then LER and LWR increase due to greater EUV absorption differences between top and bottom regions
Solution Approach 1:
The topcoat serves as a protective intermediary layer that uniformly distributes EUV-induced acid generation across the photoresist thickness, preventing the exacerbation of LER and LWR that would normally occur with increased photoresist thickness
Solution Approach 2:
The topcoat is applied beforehand to cushion and regulate the EUV energy distribution across the photoresist layer, preventing excessive acid generation at the top surface and ensuring uniform exposure throughout the thickness, thereby maintaining low LER and LWR values
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 solution significantly improves in-point uniformity and reduces LER/LWR of patterns, enhancing the formation of fine patterns and preventing defects during the photolithography process.
Implementation Method 1
enhances EUV absorption, reduces acid concentration
Implementation Method 2
improves solubility, thereby minimizing pattern roughness
Data Source
AI summary
A resist topcoat composition and a method of forming (or providing) patterns utilizing the resist topcoat composition are provided. The resist topcoat composition includes a copolymer including a first structural unit represented by Chemical Formula M-1, a second structural unit represented by Chemical Formula M-2, and a third structural unit represented by Chemical Formula M-3A or Chemical Formula M-3B; and a solvent. Details about the above chemical formulas are as described in the specification.