Immersion Lithography Resist Composition for Defect Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Immersion lithography in semiconductor manufacturing faces challenges with development defects due to the interaction between chemical amplification resists and immersion liquids, leading to uneven chemical reactions and poor pattern quality.
Innovation Solution
A pattern forming method using a positive resist composition comprising a silicon-free resin, a compound generating acid upon irradiation, a silicon-containing resin with specific groups for increased solubility, and a solvent, which involves steps of applying the resist, exposing to light through an immersion liquid, removing the liquid, heating, and developing, with optional cleaning and specific solvent usage to prevent liquid permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical amplification resist is used in immersion lithography, then sensitivity is improved, but development defects occur due to interaction with immersion liquid
Solution Approach 1:
The patent introduces a specific resist composition as an intermediary layer between the immersion liquid and the substrate. This resist composition contains specific components (silicon-free resin, silicon-containing resin with alkali-soluble groups, acid generator) that mediate the interaction with the immersion liquid, allowing chemical amplification to occur while preventing harmful interactions that cause development defects.
Solution Approach 2:
The patent modifies the chemical parameters of the resist composition by incorporating specific ratios of silicon-free resin (50-99.7 mass%), silicon-containing resin (0.1-5 mass%), and acid generator (1-20 mass%). These parameter changes enable the resist to maintain chemical amplification capability while being resistant to the immersion liquid's harmful effects during development.
2Manufacturing precision
If immersion liquid is used to enhance resolution, then focal depth is increased, but resist layer quality is altered and ingredients ooze from the resist layer
Solution Approach 1:
The patent extracts and removes harmful ingredients from the resist layer through a specific development process. The resist composition is designed so that after exposure and PEB, the unwanted ingredients can be selectively removed by the alkaline developer, leaving only the necessary components for pattern formation while maintaining resist layer integrity.
Solution Approach 2:
The patent uses a composite resist composition combining silicon-free resin, silicon-containing resin with specific groups, and acid generator. This composite material structure provides both the chemical amplification needed for high resolution and the stability to prevent ingredient oozing when in contact with immersion liquid during exposure and development.
3Reliability
If ArF excimer laser is used for exposure, then existing immersion liquid (water) is safe and transparent, but F2 excimer laser requires fluorine-containing solvents with limited environmental safety
Solution Approach 1:
The patent adapts the resist composition parameters for different exposure wavelengths. For F2 excimer laser (157 nm), the resist contains fluorine-containing components that maintain compatibility with fluorine-containing immersion liquids, ensuring both environmental safety and effective immersion lithography performance.
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
This method improves development defect reduction and ensures uniform chemical reactions, resulting in higher quality resist patterns by controlling the immersion liquid's impact on the resist coating.
Implementation Method 1
a compound capable of generating an acid upon irradiation with an actinic ray or radiation
Implementation Method 2
the method of filling the space between a projection lens and a test specimen with a liquid having a high refractive index (hereinafter referred to as an immersion liquid), or the so-called immersion method
Implementation Method 3
a silicon-containing resin having at least one group selected from the group of consisting (X) an alkali-soluble group, (XI) a group capable of decomposing under action of an alkaline developer and increasing solubility of the resin (C) in an alkaline developer
Implementation Method 4
conversion of alkali-insoluble groups into an alkali-soluble groups by utilizing the generated acid as a reaction catalyst is caused by bake after exposure (PEB: Post Exposure Bake)
Data Source
AI summary
A pattern forming method which uses a positive resist composition comprises: (A) a silicon-free resin capable of increasing its solubility in an alkaline developer under action of an acid; (B) a compound capable of generating an acid upon irradiation with an actinic ray or radiation; (C) a silicon-containing resin having at least one group selected from the group of consisting (X) an alkali-soluble group, (XI) a group capable of decomposing under action of an alkaline developer and increasing solubility of the resin (C) in an alkaline developer, and (XII) a group capable of decomposing under action of an acid and increasing solubility of the resin (C) in an alkaline developer, and (D) a solvent, the method comprising: (i) a step of applying the positive resist composition to a substrate to form a resist coating, (ii) a step of exposing the resist coating to light via an immersion liquid, (iii) a step of removing the immersion liquid remaining on the resist coating, (iv) a step of heating the resist coating, and (v) a step of developing the resist coating.