Ionic Salt Resist Composition for EUV Lithography
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Solution Overview
Problem
Current chemically amplified resists used in semiconductor lithography face challenges in achieving linewidths of 10 nm or less due to low extreme ultraviolet (EUV) absorbance and sensitivity limitations, particularly with organic materials.
Innovation Solution
Development of an ionic salt comprising a polyvalent ion with a metal cluster structure, such as tin, indium, antimony, or bismuth, combined with an organic ion like a carboxylate or sulfonate anion, which enhances EUV absorbance, sensitivity, and resolution, forming a radiation-sensitive resist composition and pattern forming method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chemically amplified resists use organic materials, then sensitivity and resolution are improved, but EUV absorbance decreases
Solution Approach 1:
The patent employs composite materials by combining organic ions with metal cluster ions (tin, indium, antimony, tellurium, or bismuth) to create ionic salts that integrate both the high sensitivity/resolution benefits of organic materials and the high EUV absorbance properties of metal clusters, thereby resolving the contradiction between improved resolution and reduced EUV absorbance
Solution Approach 2:
The patent changes the chemical composition parameters by incorporating metal clusters with specific atomic numbers (Sn: 50, In: 49, Sb: 51, Te: 52, Bi: 83) into the resist material structure, which fundamentally alters the EUV absorption characteristics while maintaining the desired resolution properties through controlled synthesis of the ionic salt composition
2Measurement precision
If chemically amplified resists are used for miniaturization, then sensitivity is improved, but EUV absorbance is insufficient
Solution Approach 1:
The patent uses composite materials strategy by creating ionic salts that combine organic ions (providing sensitivity) with metal cluster ions (providing EUV absorbance), achieving a synergistic effect where the composite structure delivers both high sensitivity and adequate EUV absorbance simultaneously
Solution Approach 2:
The patent merges the functional properties of organic materials (sensitivity) and metal clusters (EUV absorbance) into a single integrated ionic salt structure, allowing the resist composition to exhibit both high sensitivity for pattern formation and sufficient EUV absorbance for effective lithography
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 ionic salt improves EUV absorption, sensitivity, and development properties, enabling the formation of resist patterns with improved resolution and uniformity, addressing the limitations of existing chemically amplified resists in achieving sub-10 nm linewidths.
Implementation Method 1
the ionic salt has characteristics including improved radiation (EUV in particular) absorbance
Data Source
AI summary
An ionic salt includes a polyvalent ion (a) having a metal cluster structure or a metal oxide cluster structure and an organic ion (b), a radiation-sensitive resist composition including the ionic salt, and a pattern forming method, wherein the polyvalent ion (a) includes at least one metal atom selected from the group consisting of tin, indium, antimony, tellurium, and bismuth, and the organic ion (b) is at least one selected from the group consisting of: a carboxylate anion having 4 or more carbon atoms; a sulfonate anion having 4 or more carbon atoms; a phosphonate anion having 4 or more carbon atoms; a phenoxide anion having 6 or more carbon atoms; an iodonium cation having 4 or more carbon atoms; a sulfonium cation having 4 or more carbon atoms; an ammonium cation having 4 or more carbon atoms; and a pyridinium cation having 5 or more carbon atoms.